WorldWideScience

Sample records for pavement surface distress

  1. Evaluation Model for Pavement Surface Distress on 3d Point Clouds from Mobile Mapping System

    Science.gov (United States)

    Aoki, K.; Yamamoto, K.; Shimamura, H.

    2012-07-01

    This paper proposes a methodology to evaluate the pavement surface distress for maintenance planning of road pavement using 3D point clouds from Mobile Mapping System (MMS). The issue on maintenance planning of road pavement requires scheduled rehabilitation activities for damaged pavement sections to keep high level of services. The importance of this performance-based infrastructure asset management on actual inspection data is globally recognized. Inspection methodology of road pavement surface, a semi-automatic measurement system utilizing inspection vehicles for measuring surface deterioration indexes, such as cracking, rutting and IRI, have already been introduced and capable of continuously archiving the pavement performance data. However, any scheduled inspection using automatic measurement vehicle needs much cost according to the instruments' specification or inspection interval. Therefore, implementation of road maintenance work, especially for the local government, is difficult considering costeffectiveness. Based on this background, in this research, the methodologies for a simplified evaluation for pavement surface and assessment of damaged pavement section are proposed using 3D point clouds data to build urban 3D modelling. The simplified evaluation results of road surface were able to provide useful information for road administrator to find out the pavement section for a detailed examination and for an immediate repair work. In particular, the regularity of enumeration of 3D point clouds was evaluated using Chow-test and F-test model by extracting the section where the structural change of a coordinate value was remarkably achieved. Finally, the validity of the current methodology was investigated by conducting a case study dealing with the actual inspection data of the local roads.

  2. Rigid pavements distresses - pavement condition index evaluation

    OpenAIRE

    Pereira, Tiago David da Costa Prudente

    2014-01-01

    Pavements require maintenance in order to provide good service levels during their life period. Because of the significant costs of this operation and the importance of a proper planning, a pavement evaluation methodology, named Pavement Condition Index (PCI), was created by the U.S. Army Corps of Engineers. This methodology allows for the evaluation of the pavement condition along the life period, generally yearly, with minimum costs and, in this way, it is possible to plan the maintenance a...

  3. LDPE and CRMB Utilization in Bituminous Concrete Pavement Surfaces

    OpenAIRE

    Payal Bakshi

    2013-01-01

    The road traffic and the traffic intensity are also increasing. Thus the load bearing capacities of the road is to be increased. There are two types of roads - flexible pavements (bitumen roads) and rigid pavements (concrete roads). Flexible pavements (bitumen roads) comprise of the major portion of all surfaced roads. In India, bituminous surfaced flexible pavements comprise of majority of the roads. Distress symptoms, such as cracking, rutting, etc., are being increasingly caused earlier by...

  4. Improving a pavement-watering method on the basis of pavement surface temperature measurements

    CERN Document Server

    Hendel, Martin; Diab, Youssef; Royon, Laurent

    2014-01-01

    Pavement-watering has been studied since the 1990's and is currently considered a promising tool for urban heat island reduction and climate change adaptation. However, possible future water resource availability problems require that water consumption be optimized. Although pavement heat flux can be studied to improve pavement-watering methods (frequency and water consumption), these measurements are costly and require invasive construction work to install appropriate sensors in a dense urban environment. Therefore, we analyzed measurements of pavement surface temperatures in search of alternative information relevant to this goal. It was found that high frequency surface temperature measurements (more than every 5 minutes) made by an infrared camera can provide enough information to optimize the watering frequency. Furthermore, if the water retaining capacity of the studied pavement is known, optimization of total water consumption is possible on the sole basis of surface temperature measurements.

  5. Propagation Mechanisms for Surface Initiated Crackingin Composite Pavements

    OpenAIRE

    Duraid Ali Al Khafagy; Zainab Ahmed Alkaissi

    2009-01-01

    The primary objective of this study was to identify the mechanisms for the development and propagation of longitudinal cracks that initiate at the surface of composite pavement. In this study the finite element program ANSYS version (5.4) was used and the model worked out using this program has the ability to analyze a composite pavement structure of different layer properties. Also, the aim of this study was modeling and analyzing of the composite pavement structure with the physical presenc...

  6. Evaluation of multilayered pavement structures from measurements of surface waves

    Science.gov (United States)

    Ryden, N.; Lowe, M.J.S.; Cawley, P.; Park, C.B.

    2006-01-01

    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. ?? 2006 American Institute of Physics.

  7. Development and evaluation of the model for the surface pavement temperature prediction

    Directory of Open Access Journals (Sweden)

    B. Mati?

    2012-07-01

    Full Text Available This paper examines the existing models for predicting pavement temperatures and formulates a new one using a regression equation to predict the minimum and maximum pavement surface temperatures depending on the air temperature. Also, the paper presents a model for pavement temperature prediction according to the Superpave methodology and conducts the validation of the model for measured temperatures.

  8. Use of scrap rubber in asphalt pavement surfaces

    Science.gov (United States)

    Eaton, Robert A.; Roberts, Richard J.; Blackburn, Robert R.

    1991-12-01

    Scrap tire rubber was mixed into an asphalt concrete wearing course to study the effect of ice disbonding from the pavement surface under traffic. Rubber contents of 0, 3, 6, and 12 percent by weight were studied. Initial laboratory ice disbonding test results led to the development of a new paving material, Chunk Rubber Asphalt Concrete (CRAC), that uses larger pieces of rubber in a much denser asphalt concrete mix. Strength values doubled and ice disbonding performance was enhanced.

  9. Pavement Aging Model by Response Surface Modeling

    Directory of Open Access Journals (Sweden)

    Manzano-Ramírez A.

    2011-10-01

    Full Text Available In this work, surface course aging was modeled by Response Surface Methodology (RSM. The Marshall specimens were placed in a conventional oven for time and temperature conditions established on the basis of the environment factors of the region where the surface course is constructed by AC-20 from the Ing. Antonio M. Amor refinery. Volatilized material (VM, load resistance increment (?L and flow resistance increment (?F models were developed by the RSM. Cylindrical specimens with real aging were extracted from the surface course pilot to evaluate the error of the models. The VM model was adequate, in contrast (?L and (?F models were almost adequate with an error of 20 %, that was associated with the other environmental factors, which were not considered at the beginning of the research.

  10. Air Purification Pavement Surface Coating by Atmospheric Pressure Cold Plasma

    Science.gov (United States)

    Westergreen, Joe; Pedrow, Patrick; Shen, Shihui; Jobson, Bertram

    2011-11-01

    This study develops an atmospheric pressure cold plasma (APCP) reactor to produce activated radicals from precursor molecules, and to immobilize nano titanium dioxide (TiO2) powder to substrate pavement materials. TiO2 has photocatalytic properties and under UV light can be used to oxidize and remove volatile organic compounds (VOCs) and nitrogen oxides (NOx) from the atmosphere. Although TiO2 treated paving materials have great potential to improve air quality, current techniques to adhere TiO2 to substrate materials are either not durable or reduce direct contact of TiO2 with UV light, reducing the photocatalytic effect. To solve this technical difficulty, this study introduces APCP techniques to transportation engineering to coat TiO2 to pavement. Preliminary results are promising and show that TiO2 can be incorporated successfully into an APCP environment and can be immobilized at the surface of the asphalt substrate. The TiO2 coated material with APCP shows the ability to reduce nitrogen oxides when exposed to UV light in an environmental chamber. The plasma reactor utilizes high voltage streamers as the plasma source.

  11. Assessment of in-situ compaction degree of HMA pavement surface layers using GPR and novel dielectric properties-based algorithms

    Science.gov (United States)

    Georgiou, Panos; Loizos, Fokion

    2015-04-01

    Field compaction of asphalt pavements is ultimately conducted to achieve layer(s) with suitable mechanical stability. However, the achieved degree of compaction has a significant influence on the performance of asphalt pavements. Providing all desirable mixture design characteristics without adequate compaction could lead to premature permanent deformation, excessive aging, and moisture damage; these distresses reduce the useful life of asphalt pavements. Hence, proper construction of an asphalt pavement is necessary to develop a long lasting roadway that will help minimize future maintenance. This goal is achieved by verifying and confirming that design specifications, in this case density specifications are met through the use of Quality Assurance (QA) practices. With respect to in-situ compaction degree of hot mix asphalt (HMA) pavement surface layers, nearly all agencies specify either cored samples or nuclear/ non nuclear density gauges to provide density measurement of the constructed pavement. Typically, a small number of spot tests (with either cores or nuclear gauges) are run and a judgment about the density level of the entire roadway is made based on the results of this spot testing. Unfortunately, density measurement from a small number of spots may not be representative of the density of the pavement mat. Hence, full coverage evaluation of compaction quality of the pavement mat is needed. The Ground Penetrating Radar (GPR), as a Non Destructive Testing (NDT) technique, is an example of a non-intrusive technique that favors over the methods mentioned above for assessing compaction quality of asphalt pavements, since it allows measurement of all mat areas. Further, research studies in recent years have shown promising results with respect to its capability, coupled with the use of novel algorithms based on the dielectric properties of HMA, to predict the in-situ field density. In view of the above, field experimental surveys were conducted to assess the effectiveness of GPR methodology to estimate the in-situ compaction degree of several test sections. Moreover, considering also the field density results as obtained with traditional methods, comparative evaluation was conducted to assess the potential of using the GPR technique as a surrogate tool for pavement compaction quality purposes. Acknowledgements: This work has been inspired from publications of the COST action TU-1208 funded from EU.

  12. Fusing complementary images for pavement cracking measurements

    Science.gov (United States)

    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.

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

    International Nuclear Information System (INIS)

    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. (paper)

  14. Studies on stress distribution in pavements subjected to surface shear forces.

    Science.gov (United States)

    Kimura, Tsutomu

    2014-01-01

    It has been pointed out by some researchers that road pavements are subjected to vertical stress due to vehicles on them as well as shear stress at the time of braking or acceleration of vehicles. In this paper, the results of elastic analysis to obtain the rigorous solution for an elastic two-layer system subjected to surface shear stress are described and it is shown that the effect of shear stresses applied at the surface gives rise to fairly large stresses in the system. On the basis of these findings, the author attempts to explain why pavement failure takes place frequently at places such as crossings and curved parts where pavements are subjected to high magnitude of surface shear stresses. PMID:24522154

  15. Assessing the potential for restoration of surface permeability for permeable pavements through maintenance.

    Science.gov (United States)

    Drake, Jennifer; Bradford, Andrea

    2013-01-01

    Permeable pavements (PPs) have been in use as stormwater management systems in Canada and the United States for over 20 years. After years of exposure to sediment and debris build-up, surface clogging reduces the infiltration of stormwater and inhibits the hydraulic and environmental functions of the pavement. Removal of surface material has been shown to restore infiltration but the majority of studies have been limited to small-scale testing. This paper presents the results of small- and full-sized equipment testing aimed at restoring surface permeability, including the first testing of regenerative-air and vacuum-sweeping streetsweepers in Ontario. Maintenance achieved partial restoration of PP surface permeability. Post-treatment surface infiltration rates displayed large spatial variability, highlighting that localized conditions throughout the pavement have a confounding influence on the overall effectiveness of maintenance. The impact of maintenance may be improved by establishing regular cleaning intervals and developing instructional guidelines for pavement owners and equipment operators. PMID:24225094

  16. Methods to Use Surface Infiltration Tests in Permeable Pavement Systems to Determine Maintenance Frequency

    Science.gov (United States)

    Currently, there is limited guidance on selecting test sites to measure surface infiltration rates in permeable pavement systems to determine maintenance frequency. The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete suggest to either (1) p...

  17. Influence of changes in surface layer properties on tire/pavement noise:

    OpenAIRE

    Li, M.; Van Keulen, W.; H. CEYLAN; Ven, M.F.C. van de; Molenaar, A.A.A.

    2013-01-01

    This paper investigates changes in tire/pavement noise caused by variations in the road surface characteristics. This research is based on the analysis of noise and surface characteristics collected from sections with 25 mm thickness thin layer surfacings in the Netherlands. Investigations are first performed on the measured noise levels in 1/3rd octave bands, texture levels and the sound absorption curves. The one-way analysis of variance is employed to test the changes of noise caused by va...

  18. Experimental Evaluation of Anti-Stripping Additives Mixing in Road Surface Pavement Materials

    OpenAIRE

    Tienfuan Kerh; Yu-Min Wang; Yulern Lin

    2005-01-01

    Most road surfaces in Taiwan are paved with asphalt concrete but the phenomena of rutting, cracking and stripping of the pavement are frequently occurring due to the effects of traffic flow, thermal variation and water erosion caused by rain. In this study, a series of experiments were performed to examine the effectiveness of anti-stripping fillers, which include; rock flour, rock flour with 1% lime and rock flour with 1% cement, respectively, in the mixture of asphalt concrete. The experime...

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

    Science.gov (United States)

    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

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

    Directory of Open Access Journals (Sweden)

    Gabriele Bitelli

    2012-07-01

    Full Text Available 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.

  1. Visual surveying platform for the automated detection of road surface distresses

    Science.gov (United States)

    Naidoo, Thegaran; Joubert, Deon; Chiwewe, Tapiwa; Tyatyantsi, Ayanda; Rancati, Bruno; Mbizeni, Asanda

    2014-06-01

    Road distresses, such as potholes and edge cracks, are not only a source of frustration to drivers but also negatively impact the economy due to damage to motor vehicles and costly ro6ad repairs. Regular and rapid pavement inspection and maintenance is vital to preventing pothole formation and growth. To improve the efficiency of maintenance and reduce the cost thereof, the Visual Surveying Platform (VSP) is being developed that will automatically detect and analyse road distresses. The VSP consists of a vehicle mounted sensor system, consisting of a high speed camera and a Global Positioning System (GPS) receiver, and an analysis and visualization software suite. The system extracts both a visual image and the coordinates of a detected road defect from recorded video and presents it in an interactive interface for use by technical experts and maintenance schedulers. The VSP automatically detects and classifies road distresses using a two-stage artificial neural network framework. Video frames first undergo hue, saturation and value (HSV) colour space conversion as well as a spatial frequency transformation before being used as inputs to the neural networks. A road detector neural network first classifies which section of the image contains the road, after which a distress detector neural network identifies those road regions containing defects. Although the VSP can be adapted to detect any type of road distress it has been trained to specifically detect potholes. An initial prototype of the VSP was designed and constructed. The prototype was also trained and tested on real-world data collected from provincial roads.

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

    OpenAIRE

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

    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 practice...

  3. Studies on stress distribution in pavements subjected to surface shear forces

    OpenAIRE

    Kimura, Tsutomu

    2014-01-01

    It has been pointed out by some researchers1,2) that road pavements are subjected to vertical stress due to vehicles on them as well as shear stress at the time of braking or acceleration of vehicles. In this paper, the results of elastic analysis to obtain the rigorous solution for an elastic two-layer system subjected to surface shear stress are described and it is shown that the effect of shear stresses applied at the surface gives rise to fairly large stresses in the system. On the basis ...

  4. EFFECTS OF PAVEMENT SURFACE TEMPERATURE ON THE MODIFICATION OF URBAN THERMAL ENVIRONMENT

    Directory of Open Access Journals (Sweden)

    SARAT, Adebayo-Aminu

    2012-01-01

    Full Text Available Urban centres continue to experience escalating average summer temperature over the last fifty years. Temperature in the urban core cites have been rising due to rapid growth of urbanization in the latter half of the twentieth century (Akbari et al., 1989. Outdoor experiments were conducted to investigate the effects of different movement of materials on the urban thermal environment. Meteorological conditions such as air temperature, pavement surface temperature, Relative humidity and wind velocity were recorded to determine temperature differences among Asphalt/concrete, interlocking bricks and grass surfaces.

  5. Shakedown analysis and design of flexible road pavements under moving surface loads

    OpenAIRE

    Wang, Juan

    2011-01-01

    Flexible road pavements often fail due to excessive rutting. as a result of cumulative vertical permanent deformation under repeated traffic loads. The currently used analytical approach to flexible pavement design evaluates the pavement life in terms of critical elastic strain at the top of the subgrade. Hence, the plastic pavement behaviour is not properly considered. Shakedown analysis can take into account the material plasticity and guarantee structure stability under repeated loads. It ...

  6. Evaluation of Surface Infiltration Testing Procedures in Permeable Pavement Systems

    Science.gov (United States)

    The ASTM method (ASTM C1701) for measuring infiltration rate of in-place pervious concrete provides limited guidance on how to select testing locations, so research is needed to evaluate how testing sites should be selected and how results should be interpreted to assess surface ...

  7. Fast simulated annealing inversion of surface waves on pavement using phase-velocity spectra

    Science.gov (United States)

    Ryden, N.; Park, C.B.

    2006-01-01

    The conventional inversion of surface waves depends on modal identification of measured dispersion curves, which can be ambiguous. It is possible to avoid mode-number identification and extraction by inverting the complete phase-velocity spectrum obtained from a multichannel record. We use the fast simulated annealing (FSA) global search algorithm to minimize the difference between the measured phase-velocity spectrum and that calculated from a theoretical layer model, including the field setup geometry. Results show that this algorithm can help one avoid getting trapped in local minima while searching for the best-matching layer model. The entire procedure is demonstrated on synthetic and field data for asphalt pavement. The viscoelastic properties of the top asphalt layer are taken into account, and the inverted asphalt stiffness as a function of frequency compares well with laboratory tests on core samples. The thickness and shear-wave velocity of the deeper embedded layers are resolved within 10% deviation from those values measured separately during pavement construction. The proposed method may be equally applicable to normal soil site investigation and in the field of ultrasonic testing of materials. ?? 2006 Society of Exploration Geophysicists.

  8. Weak interlayers in flexible and semi-flexible road pavements: Part 1

    Scientific Electronic Library Online (English)

    F, Netterberg; M, de Beer.

    2012-04-01

    Full Text Available Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers [...] , it is shown that from experience with heavy vehicle simulator (HVS) and dynamic cone penetrometer (DCP) testing, the presence of such layers and/or conditions at any depth in the structural layers of a flexible or semi-flexible pavement is far more deleterious than is commonly appreciated. In Part 2 the effects of these weak layers are further modelled and discussed using various examples based an HVS testing and mechanistic pavement analyses. In particular, a weak upper base course of a cemented pavement under a thin bituminous surfacing may lead to severe surfacing (and upper base) failure within a matter of weeks to months after opening to traffic, not excluding failure even during construction. In this paper (Part 1), the causes of weak layers, interlayers, laminations and/or interfaces, together with simple methods for their detection during construction and analyses of their effects on the structural capacity of flexible and semi-rigid (cemented) road pavements, are briefly discussed.

  9. Weak interlayers in flexible and semi-flexible road pavements: Part 1

    Directory of Open Access Journals (Sweden)

    F Netterberg

    2012-04-01

    Full Text Available Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers, it is shown that from experience with heavy vehicle simulator (HVS and dynamic cone penetrometer (DCP testing, the presence of such layers and/or conditions at any depth in the structural layers of a flexible or semi-flexible pavement is far more deleterious than is commonly appreciated. In Part 2 the effects of these weak layers are further modelled and discussed using various examples based an HVS testing and mechanistic pavement analyses. In particular, a weak upper base course of a cemented pavement under a thin bituminous surfacing may lead to severe surfacing (and upper base failure within a matter of weeks to months after opening to traffic, not excluding failure even during construction. In this paper (Part 1, the causes of weak layers, interlayers, laminations and/or interfaces, together with simple methods for their detection during construction and analyses of their effects on the structural capacity of flexible and semi-rigid (cemented road pavements, are briefly discussed.

  10. Experimental Evaluation of Anti-Stripping Additives Mixing in Road Surface Pavement Materials

    Directory of Open Access Journals (Sweden)

    Tienfuan Kerh

    2005-01-01

    Full Text Available Most road surfaces in Taiwan are paved with asphalt concrete but the phenomena of rutting, cracking and stripping of the pavement are frequently occurring due to the effects of traffic flow, thermal variation and water erosion caused by rain. In this study, a series of experiments were performed to examine the effectiveness of anti-stripping fillers, which include; rock flour, rock flour with 1% lime and rock flour with 1% cement, respectively, in the mixture of asphalt concrete. The experimental mixing results showed that the case of rock flour with 1% lime has a relatively better performance in several categories including stability value, flow value, retained strength, wrapped asphalt rate in grains, resilient modulus, dynamic stability and rate of rutting deformation. The evaluated information implies that this filler can increase the asphalt concrete’s abilities to resist rutting deformation and stripping of the road surface, thus increasing the durability. The results also provide a good reference for using in road construction with similar regional characteristics to Taiwan.

  11. Quality assessment of the pavement structure

    OpenAIRE

    Kras?ovec, Tibor

    2007-01-01

    Pavement surface as part of road is due to provide as safe, comfortable and economical drive to its user, as possible. Beside aforementioned, the quality level of pavement structure must be high enough to provide an adequate pavement life time. In order to ensure this demands, I prepared the Schedule of providing quality to pavement structures, which is the basic topic of this assignment. The Schedule refers to asphalt mixtures that are installed in asphalt surfacing and asphalt base course o...

  12. The Impact of Cloud Type on Surface Radiation and Road Pavement Temperature

    Science.gov (United States)

    Walker, C. L.; Anderson, A.; Chapman, M.; Drobot, S.

    2012-12-01

    Forecast systems provide decision support for end-users ranging from the solar energy industry to municipalities concerned with winter road maintenance. The racing community also relies on racetrack pavement temperature forecast systems because tire friction decreases as temperature increases, affecting vehicle performance. Race crews perform vehicle maintenance (e.g., tire pressure and suspension adjustments) to maximize traction given a forecasted racetrack temperature. Many forecast systems suffer from inaccurate radiation forecasts resulting in part from a lack of information relating radiation to cloud types. This research seeks to improve the forecasts by determining how cloud type impacts the amount of solar radiation reaching the surface. Cloud type information was obtained from the Naval Research Laboratory Cloud Classifier algorithm and radiation data were obtained from a Davis Weather Station. A theoretical maximum solar radiation distribution was calculated. Cloud type-radiation distribution analyses from Salisbury, North Carolina during May-June 2012 indicated that low clouds allowed approximately 20% of the maximum possible radiation to reach the surface, mid level clouds 32%, high clouds 40% and cumuliform types 34%. A categorical regression analysis revealed 33% of the variation in solar radiation on cloudy case days can be explained by cloud type. Inclusion of clear case days with apparent variability lowered this to 7% suggesting another influence on radiation. A similar bulk statistical analysis is in progress on a much larger data set obtained from the Oklahoma Mesonet. This work lays the foundation for use of satellite cloud type information in order to improve the output of forecast systems. Distribution of mean solar radiation measured at the surface for all nine case studies, sorted by cloud type height characteristics, where n represents the sample size.

  13. Mechanistic-Empirical Modelling of Flexible Pavement Performance : Verifications Using APT Measurements

    OpenAIRE

    Ahmed, Abubeker Worake

    2014-01-01

    Mechanistic-Empirical  (M-E)  pavement  design  procedures  are  composed  of  a  reliable  response model to estimate the state of stress in the pavement and distress models in order to predict the different types of pavement distresses due to the prevailing traffic and environmental conditions. One of the main objectives of this study was to develop a response model based on multilayer elastic  theory   (MLET)  with  improved  computational  performance  by   optimizing?...

  14. A Framework for Quantification of Effect of Drainage Quality on Structural and Functional Performance of Pavement

    OpenAIRE

    Jitendra Gurjar, Pradeep Kumar Agarwal

    2013-01-01

    Drainage quality is an important parameter which affects the highway pavement performance. Excessive water content in the pavement base, sub-base, and sub-grade soils can cause early distress and lead to a structural or functional failure of pavement. Thus, when selecting appropriate maintenance strategies the cost of pavement maintenance needs to be compared with the cost of improving the quality of drainage. Hence, there is a need to quantify the effect of va...

  15. Determination of the heating temperature of potholes surface on road pavement in the process of repairs using hot asphalt concrete mixes

    Directory of Open Access Journals (Sweden)

    Giyasov Botir Iminzhonovich

    2014-12-01

    Full Text Available In the process of roads construction the necessary transport and operational characteristics should be achieved, which depend on the quality of the applied, material and technologies. Under the loads of transport means and the influence of weather conditions on the road pavement deformations and destructions occur, which lead to worsening of transport and operational characteristics, decrease of operational life of the road and they are often the reason of road accidents. According to the data of the Strategic Research Center of "Rosgosstrah" more than 20 % of road accidents in Russia occur due to bad quality of road pavement. One of the main directions in traffic security control and prolongation of operational life for road pavement of non-rigid type is road works, as a result of which defects of pavement are eliminated and in case of timely repairs of high quality the operational life of the road increases for several years. The most widely used material for non-rigid pavement repairs is hot road concrete mixes and in case of adherence to specifications they provide high quality of works. The authors investigate the problems of hot asphalt concrete mixes for repairs of road surfaces of non-rigid type. The results of the study hot asphalt concrete mix’s temperature regimes are offered in case of repair works considering the temperature delivered to the work site and the ambient temperature depending on the type of mix and class of bitumen.

  16. Experimental pavement delineation treatments

    Science.gov (United States)

    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.

  17. Mechanistic interpretation of nondestructive pavement testing deflections

    Science.gov (United States)

    Hoffman, M. S.

    1980-06-01

    A method is proposed for the backcalculation of material properties in flexible pavements based on the interpretation of surface deflection measurements. ILLI-PAVE, a stress dependent finite element pavement model, was used to generate data for developing algorithms and nomographs for deflection basin interpretation. Over 11,000 deflection measurements for 24 different flexible pavement sections were collected and analyzed. Deflections were measured using the Benkelman Beam, the IDOT Road Rater, the Falling Weight Deflectometer, and an accelerometer to measure deflections under moving trucks. Loading mode effects on pavement response were investigated using dynamic and viscous pavement models. The factors controlling the pavement response to different loading modes were explained and identified. Correlations between different devices were developed. The proposed evaluation procedure is illustrated for three different flexible pavements using deflection data collected on several testing dates.

  18. Pavement Performance Modeling – A Case Study

    Directory of Open Access Journals (Sweden)

    Saranya Ullas

    2013-08-01

    Full Text Available Pavement deterioration is a complex process. It involves not only structural fatigue but also many functional distresses of pavement. It results from the interaction between traffic, climate, material and time. Deterioration is the term used to represent the change in pavement performance overtime. The ability of the road to satisfy the demands of traffic and environment over its design life is referred to as performance. Due to the great complexity of the road deterioration process, performance models are the best approximate predictors of expected conditions. In this study main distresses were identified from the selected road stretches. Regression models are then developed using SPSS (Statistical packages for social sciences package. T test is used to check the reliability of the model.

  19. Technical and Economic Sustainability of Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Laura Moretti

    2014-04-01

    Full Text Available Economic evaluation of road pavements is as important as their technical and structural design: often only initial construction costs are calculated to assess economic project sustainability. Instead, forgetting maintenance costs exposes society to unacceptable risks of expensive and incorrect decisions. Road pavements design and construction solutions affect maintenance works during service life, which not only entail economical and financial expenditures, but also damage service regularity for users and affect environmental impact. The analysis of pavement distress and the study of its evolution during service life can contribute to find the financially most advantageous solution. This paper shows a software program developed to analyze structural, functional and financial performances of road concrete pavements both doweled slabs and continuously reinforced.

  20. In situ determination of layer thickness and elastic moduli of asphalt pavement systems by spectral analysis of surface waves (SASW) method

    International Nuclear Information System (INIS)

    Spectral analysis of surface waves (SASW) is a non-destructive and in situ method for determining the stiffness profile of soil and pavement sites. The method consists of generation, measurement, and processing of dispersive elastic waves in layered systems. The test is performed on the pavement surface at strain level below 0.001%, where the elastic properties are considered independent of strain amplitude. During an SASW test, the surface of the medium under investigation is subject to an impact to generate energy at various frequencies. Two vertical acceleration transducers are set up near the impact source to detect the energy transmitted through the testing media. By recording signals in digitised form using a data acquisition system and processing them, surface wave velocities can be determined by constructing a dispersion curve. Through forward modeling, the shear wave velocities can be obtained, which can be related to the variation of stiffness with depth. This paper presents the results of two case studies for near?surface profiling of two different asphalt pavement sites. (Author)

  1. An experience on street pavement maintenance program in small region- (Bafq city

    Directory of Open Access Journals (Sweden)

    Khabiry Mehdi

    2009-05-01

    Full Text Available This paper reports an experience on Pavement Maintenance plan of the Research Team of the Islamic Azad University- Bafq Branch. The City of Bafq streets are failing at a growing rate, despite all the efforts of Pavement Management, improved efficiencies in street maintenance operations, contracted work and sharing equipment with other agencies. Pavements in this range show some form of distress or wear that requires more than a life extending achievement. In this group, a well-designed pavement will have served at least 75% of its life and the authority of the pavement has dropped by about 40%.

  2. A model for the pavement temperature prediction at specified depth

    Directory of Open Access Journals (Sweden)

    B. Mati?

    2013-10-01

    Full Text Available This paper examines the existing models for predicting pavement temperatures at a certain depth and formulates a new one using the regression equation to predict the minimum and maximum pavement temperatures at the specified depth depending on the surface pavement temperature and its depth.

  3. Analysis of pavement serviceability for the Aashto Design Method: The Chilean Case

    International Nuclear Information System (INIS)

    Serviceability is an indicator that represents the level of service a pavement provides to the users. This subjective opinion is closely related to objective aspects, which can be measured on the pavement's surface. This research aims specifically at relating serviceability results obtained by a 9-member evaluation panel, representing general public as closely as possible to parameters (particularly of roughness) measured within instruments on 30, 25 and 11 road sections of asphalt concrete, Portland cement concrete and asphalt overlay respectively. Results show that prediction of serviceability is quite accurate based on roughness evaluation, while also revealing that, by comparison to studies in more developed countries, Chileans are seemingly more tolerant, in that they assign a somewhat high rating to ride quality. Furthermore, visible distress does not have a significant influence on serviceability values for Chilean users. A ratio between International Roughness Index (IRI) and Serviceability, as defined by AASHTO, was developed and may be used in this design method. Results for the final pavement condition of urban pavements were obtained (IRI-asphalt final=5.9, IRI-concrete final=8.1). (author)

  4. Reliability-based Design Procedure for Flexible Pavements

    OpenAIRE

    Dinegdae, Yared Hailegiorgis

    2015-01-01

    Load induced top-down fatigue cracking has been recognized recently as a major distress phenomenon in asphalt pavements. This failure mode has been observed in many parts of the world, and in some regions, it was found to be more prevalent and a primary cause of pavements failure. The main factors which are identified as potential causes of top down fatigue cracking are primarily linked to age hardening, mixtures fracture resistance and unbound layers stiffness. Mechanistic Empirical analytic...

  5. Study on Flexible Pavement Failures in Soft Soil Tropical Regions

    Science.gov (United States)

    Jayakumar, M.; Chee Soon, Lee

    2015-04-01

    Road network system experienced rapid upgrowth since ages ago and it started developing in Malaysia during the colonization of British due to its significant impacts in transportation field. Flexible pavement, the major road network in Malaysia, has been deteriorating by various types of distresses which cause descending serviceability of the pavement structure. This paper discusses the pavement condition assessment carried out in Sarawak and Sabah, Malaysia to have design solutions for flexible pavement failures. Field tests were conducted to examine the subgrade strength of existing roads in Sarawak at various failure locations, to assess the impact of subgrade strength on pavement failures. Research outcomes from field condition assessment and subgrade testing showed that the critical causes of pavement failures are inadequate design and maintenance of drainage system and shoulder cross fall, along with inadequate pavement thickness provided by may be assuming the conservative value of soil strength at optimum moisture content, whereas the exiting and expected subgrade strengths at equilibrium moisture content are far below. Our further research shows that stabilized existing recycled asphalt and base materials to use as a sub-base along with bitumen stabilized open graded base in the pavement composition may be a viable solution for pavement failures.

  6. Measurement of the Cooling Efficiency of Pavement-Watering as an Urban Heat Island Mitigation Technique

    Directory of Open Access Journals (Sweden)

    Martin Hendel

    2015-03-01

    Pavement watering was found to lower pavement surface temperatures by several degrees for several hours after watering, while also strongly reducing its cooling rate a few hours before and after sunset. Heat flux and storage at a depth of 5 cm in the pavement were also found to have been significantly reduced, especially during direct sunlight exposure, but also when the pavement was in the shade. Uninterrupted watering appears necessary during direct sunlight exposure of the pavement to maximize efficiency.

  7. Monitoring the condition of roads pavement surfaces: proposal of methodology using hyperspectral images / Monitoramento das condições das superfícies de pavimentos rodoviários: proposta de metodologia utilizando imagens hiperespectrais

    Scientific Electronic Library Online (English)

    Marcos Ribeiro, Resende; Liedi Legi Bariani, Bernucci; José Alberto, Quintanilha.

    2014-04-01

    Full Text Available No atual sistema de concessões rodoviária do Brasil ambos, concessionárias e agências reguladoras têm a missão de melhorar a qualidade dos pavimentos rodoviários no País. Tal situação requer a pesquisa e a identificação de novas ferramentas que facilitem o levantamento das condições dos pavimentos r [...] odoviários num tempo e custos menores que os métodos usuais. Recentemente, se verificou um grande aumento da disponibilidade de imagens de sensoriamento remoto com alta resolução espacial, seguindo uma tendência do mercado de novos satélites de sensoriamento remoto, e de sensores aerotransportados. De forma similar, imagens multi e hiperespectrais estão disponíveis tanto comercialmente quanto para a pesquisa científica. O artigo apresenta uma nova metodologia para a identificação das condições do asfalto em superfícies pavimentadas e uma classificação dos tipos de defeitos identificáveis a partir de imagens hiperespectrais adquiridas por sensores aerotransportados. O objetivo do artigo é o de mostrar que índices das condições das superfícies dos pavimentos asfaltados gerados via imagens hiperespectrais podem ser comparados com os indicadores vigentes, utilizados pela agência reguladora nacional. Abstract in english With the current system of concession roads in Brazil, both concessionaires and regulatory agents have been charged with improving the quality of the pavement on Brazilian highways. This situation requires the search for new tools that can facilitate the survey of pavement conditions in less time an [...] d at a lower cost than traditional methods. Recently, an increasing number of high-resolution spatial images have become available on the world market following the development of new remote sensing satellites and airborne sensors. Similarly, multispectral images and even hyperspectral images are now available commercially and for scientific research. The paper presents a new methodology for the identification of asphalted pavement surfaces condition and the classification of the main types of asphalt defects using hyperspectral images from airborne digital sensors. The objective of this study was to generate indexes of pavement conditions from images that can be compared with the indicators of pavement surface conditions already used by national regulatory agencies.

  8. Permeable Pavement Research - Edison, New Jersey

    Science.gov (United States)

    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. Effect Of Geopathic Stress On Bituminous Pavement

    Directory of Open Access Journals (Sweden)

    B.H.CHAFEKAR

    2013-06-01

    Full Text Available This paper basically for the investigation of Geopathic Stress Zones along the road. Geopathic stress is detrimental energy emanating from the earth and leading to long-term harm to susceptible humans, animals and plants which are exposed to them in their environment. Detection of geopathic location has been done by Experimental investigations on road alignment of one KM, by performing distresses survey, dowsing and by magnetic field detector to investigate the Geopathic Stress. Due to such energies emitted by the earth distresses may occurs on road pavements. It is found that, where geopathic stress occurs a copper L rod gets deflected, also get abrupt changes in magnetic field where the distresses occurs.

  10. 76 FR 67018 - Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather Information Systems

    Science.gov (United States)

    2011-10-28

    ...in-pavement runway sensor systems comply with the performance...Runway Weather Information System (In-pavement). The SAE specification is available for purchase at...runway surface condition sensor system project that includes any...

  11. Rough thin pavement thickness estimation by GPR

    OpenAIRE

    Pinel, Nicolas; Le Bastard, Ce?dric; Liu, Limei; Bourlier, Christophe; Wang, Yide

    2009-01-01

    In civil engineering, usually the methods used to estimate the thickness of thin pavements consider flat interfaces for simplification. In this paper, the roughness of the surfaces is taken into account. First, the amplitudes of the first two echoes from the rough thin pavement are calculated from a rigorous electromagnetic method, the PILE method. A comparison is then made with the flat interface case, and their differences in the electromagnetic backscattering are highlighted. Eventually, t...

  12. Hybrid green permeable pave with hexagonal modular pavement systems

    International Nuclear Information System (INIS)

    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.h safety factor for daily life vehicles.

  13. Hybrid green permeable pave with hexagonal modular pavement systems

    Science.gov (United States)

    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.

  14. FUEL CONSUMPTION & ENERGY DISSIPATION THROUGH ROAD PAVEMENT CHARACTERISTIC

    Directory of Open Access Journals (Sweden)

    Dipanjan Mukherjee

    2014-06-01

    Full Text Available This thesis estimates the effect of pavement characteristic on energy dissipation of a rolling vehicle tyre. On objective of this study is to compare the relative amount of energy dissipated in pavement by the rolling depending on the pavement materials surface condition & environmental condition also. The study also assesses the effect of the vertical deflection, induced by the tyre, on overall energy dissipation in pavement. A comprehensive literature was carried out to prove a wide background for the study. Field measures and laboratory tests were discussed to provide basis for analyses. Results indicate that energy dissipated in pavement significantly depend on the characteristic of pavement. An obvious influence of speed on energy dissipation can be found only when the stiffness in a low level.

  15. Field Evaluation of Nondestructive Tests in Measuring the Pavement Layers Density

    Directory of Open Access Journals (Sweden)

    H. Divandary

    2010-01-01

    Full Text Available The aim of this study was field evaluation of nondestructive devices in measuring the density of road layers. Density may be considered as a reliable criterion for evaluating pavement quality and has a high level of importance in that it can ensure the proper performance of pavement at least prior the period of life-time. At present time, the most current and also accurate method to determine in-situ density of asphalt mixture is core sample method, however it has some disadvantages. As well as being costly and time consuming, core sample method causes some distress on the pavement surface and it is not possible to repeat the test for a specific location. In view of this, some attempts were made to develop new methods as alternatives for core sample method. And as such, nondestructive tests have grown into a huge area over the last few years. These tests including nuclear and nonnuclear nondestructive tests do not have the limitations of core sample method. In this study, field evaluation in a new constructed part of a highway was conducted using pavement quality indicator (PQI301 and Troxler nuclear gauge (Model HS-5001EZ. According to the results of validation tests for nondestructive devices (PQI and Nuclear devices, PQI device has sufficient reliability to determine density of asphalt mixture layer but Nuclear device is not reliable to determine density. The obtained results from validation of nuclear device revealed that it has sufficient reliability to determine density of soil layers. Also it was found that the role of calibration procedure in obtaining correct readings From PQI device is highly critical.

  16. Modeling the Deflection Basin of Flexible Highway Pavements by Gene Expression Programming

    OpenAIRE

    Serdal Terzi

    2005-01-01

    In this study, Gene Expression Programming (GEP) is used in modeling the deflection basins measured on the surface of the flexible pavements. Backcalculation of the pavement layer moduli are well-accepted procedures for the evaluation of the structural capacity of pavements. The ultimate aim of the backcalculation process from Nondestructive Testing (NDT) results is to estimate the pavement material properties. Using backcalculation analysis, in situ material properties can be backcalculated ...

  17. Some advances/results in monitoring road cracks from 2D pavement images within the scope of the collaborative FP7 TRIMM project

    Science.gov (United States)

    Baltazart, Vincent; Moliard, Jean-Marc; Amhaz, Rabih; Wright, Dean; Jethwa, Manish

    2015-04-01

    Monitoring road surface conditions is an important issue in many countries. Several projects have looked into this issue in recent years, including TRIMM 2011-2014. The objective of such projects has been to detect surface distresses, like cracking, raveling and water ponding, in order to plan effective road maintenance and to afford a better sustainability of the pavement. The monitoring of cracking conventionally focuses on open cracks on the surface of the pavement, as opposed to reflexive cracks embedded in the pavement materials. For monitoring surface condition, in situ human visual inspection has been gradually replaced by automatic image data collection at traffic speed. Off-line image processing techniques have been developed for monitoring surface condition in support of human visual control. Full automation of crack monitoring has been approached with caution, and depends on a proper manual assessment of the performance. This work firstly presents some aspects of the current state of monitoring that have been reported so far in the literature and in previous projects: imaging technology and image processing techniques. Then, the work presents the two image processing techniques that have been developed within the scope of the TRIMM project to automatically detect pavement cracking from images. The first technique is a heuristic approach (HA) based on the search for gradient within the image. It was originally developed to process pavement images from the French imaging device, Aigle-RN. The second technique, the Minimal Path Selection (MPS) method, has been developed within an ongoing PhD work at IFSTTAR. The proposed new technique provides a fine and accurate segmentation of the crack pattern along with the estimation of the crack width. HA has been assessed against the field data collection provided by Yotta and TRL with the imaging device Tempest 2. The performance assessment has been threefold: first it was performed against the reference data set including 130 km of pavement images over UK roads, second over a few selected short sections of contiguous pavement images, and finally over a few sample images as a case study. The performance of MPS has been assessed against an older image data base. Pixel-based PGT was available to provide the most sensitive performance assessment. MPS has shown its ability to provide a very accurate cracking pattern without reducing the image resolution on the segmented images. Thus, it allows measurement of the crack width; it is found to behave more robustly against the image texture and better matched for dealing with low contrast pavement images. The benchmarking of seven automatic segmentation techniques has been provided at both the pixel and the grid levels. The performance assessment includes three minimal path selection algorithms, namely MPS, Free Form Anisotropy (FFA), one geodesic contour with automatic selection of points of interests (GC-POI), HA, and two Markov-based methods. Among others, MPS approach reached the best performance at the pixel level while it is matched to the FFA approach at the grid level. Finally, the project has emphasized the need for a reliable ground truth data collection. Owing to its accuracy, MPS may serve as a reference benchmark for other methods to provide the automatic segmentation of pavement images at the pixel level and beyond. As a counterpart, MPS requires a reduction in the computing time. Keywords: cracking, automatic segmentation, image processing, pavement, surface distress, monitoring, DICE, performance

  18. Vehicle dynamic response due to pavement roughness

    Directory of Open Access Journals (Sweden)

    Roberto Spinola Barbosa

    2011-09-01

    Full Text Available The goal of the present study is the development of a spectral method to obtain the frequency response of the half-vehicle subjected to a measured pavement roughness in the frequency domain. For this purpose, a half-vehicle dynamic model with a two-point delayed base excitation was developed to correlate with the spectral density function of the pavement roughness, to obtain the system spectral transfer function, in the frequency domain. The vertical pavement profile was measured along two roads sections. The surface roughness was here expressed in terms of the spectral density function of the measured vertical pavement profile with respect to the evenness wave number of the pavement roughness. A frequency response analysis was applied to obtain the vertical and angular modal vehicle dynamic response with the excitation of the power spectral density (PSD of the pavement roughness. The results show that at low speed, the vehicle suspension mode is magnified due to the unpaved track signature. At 120 km/h in an undulated asphalted road, the first vehicle vibration mode has a significant motion amplification, which may cause passenger discomfort.

  19. Vehicle dynamic response due to pavement roughness

    Scientific Electronic Library Online (English)

    Roberto Spinola, Barbosa.

    2011-09-01

    Full Text Available The goal of the present study is the development of a spectral method to obtain the frequency response of the half-vehicle subjected to a measured pavement roughness in the frequency domain. For this purpose, a half-vehicle dynamic model with a two-point delayed base excitation was developed to corr [...] elate with the spectral density function of the pavement roughness, to obtain the system spectral transfer function, in the frequency domain. The vertical pavement profile was measured along two roads sections. The surface roughness was here expressed in terms of the spectral density function of the measured vertical pavement profile with respect to the evenness wave number of the pavement roughness. A frequency response analysis was applied to obtain the vertical and angular modal vehicle dynamic response with the excitation of the power spectral density (PSD) of the pavement roughness. The results show that at low speed, the vehicle suspension mode is magnified due to the unpaved track signature. At 120 km/h in an undulated asphalted road, the first vehicle vibration mode has a significant motion amplification, which may cause passenger discomfort.

  20. Weak interlayers in flexible and semi-flexible road pavements: Part 1

    OpenAIRE

    Netterberg, F.; Beer, M.

    2012-01-01

    Weak layers, interlayers, laminations and/or interfaces in the upper structural layers of road pavements are specifically prohibited in most road-building specifications. However, such layers are extremely common and often lead to premature pavement distress. In Part 1 of this two-part set of papers, it is shown that from experience with heavy vehicle simulator (HVS) and dynamic cone penetrometer (DCP) testing, the presence of such layers and/or conditions at any depth in the structural layer...

  1. A Framework for Quantification of Effect of Drainage Quality on Structural and Functional Performance of Pavement

    Directory of Open Access Journals (Sweden)

    Jitendra Gurjar, Pradeep Kumar Agarwal, Manoj Kumar Sharma

    2013-07-01

    Full Text Available Drainage quality is an important parameter which affects the highway pavement performance. Excessive water content in the pavement base, sub-base, and sub-grade soils can cause early distress and lead to a structural or functional failure of pavement. Thus, when selecting appropriate maintenance strategies the cost of pavement maintenance needs to be compared with the cost of improving the quality of drainage. Hence, there is a need to quantify the effect of various types of drainage quality on performance of the pavement. However, very few studies have investigated to what extent quality of drainage affects the performance of pavement. Therefore, this study identifies a simple framework for quantification of effect of drainage quality on structural as well as functional performance of the pavement. The proposed framework presents the structural and functional performance of the pavement is predicted in terms of deflection and roughness respectively. It is expected that this study will useful to reduce the maintenance cost of highway pavement system and hence will be useful to preserve huge highway network in India.

  2. Asphalt in Pavement Maintenance.

    Science.gov (United States)

    Asphalt Inst., College Park, MD.

    Maintenance methods that can be used equally well in all regions of the country have been developed for the use of asphalt in pavement maintenance. Specific information covering methods, equipment and terminology that applies to the use of asphalt in the maintenance of all types of pavement structures, including shoulders, is provided. In many…

  3. Studies of the effect of aging of ``quiet'' pavements on tire/pavement noise

    Science.gov (United States)

    Reyff, James A.; Donavan, Paul

    2005-09-01

    One of the issues with using quieter pavements to abate traffic noise is their continued acoustic performance over the life cycle of the surface. Aging effects can be assessed in two manners: (1) long term monitoring of the noise performance of an individual section of roadway; (2) measurement of multiple sections of pavement of the same construction, but different ages. Long term monitoring of Interstate 80 near Davis (I-80 Davis) began in 1998, just prior to the placement of a dense graded leveling course and open graded asphalt overlay. The pavement surface is now approaching 7 years old and continues to show a traffic noise reduction of about 5 dBA over the existing condition. As support of the Arizona Quiet Pavement Program (QPPP), similarly constructed sections of asphalt rubber friction course (ARFC) on Arizona's interstate highways were measured for tire/pavement performance using the close proximity (CPX) method and the on-board sound intensity method. The construction dates for the pavements ranged from 1988 to 1999. The total range in noise level was 7 dB with some indication of degrading performance with age.

  4. Classificação híbrida: pixel a pixel e baseada em objetos para o monitoramento da condição da superfície dos pavimentos rodoviários / Hybrid classification: pixel by pixel and object based to monitor the surface conditions of road pavements

    Scientific Electronic Library Online (English)

    Marcos Ribeiro, Resende; Liedi Légi Barianni, Bernucci; José Alberto, Quintanilha.

    2012-09-01

    Full Text Available Monitorar a condição de uso de toda a extensão das rodovias brasileiras é tarefa dispendiosa e demorada. Este trabalho trata de novas técnicas que permitem o levantamento da condição da superfície dos pavimentos rodoviários de forma ágil utilizando imagens hiperespectrais de sensor digital aeroembar [...] cado. Nos últimos anos, um número crescente de imagens de alta resolução espacial tem surgido no mercado mundial com o aparecimento dos novos satélites e sensores aeroembarcados de sensoriamento remoto. Propõe-se uma metodologia para identificação dos pavimentos asfálticos e classificação das principais ocorrências dos defeitos na superfície do pavimento. A primeira etapa da metodologia é a identificação da superfície asfáltica na imagem, utilizando uma classificação híbrida baseada inicialmente em pixel e depois refinada por objetos. A segunda etapa da metodologia é a identificação e classificação das ocorrências dos principais defeitos nos pavimentos flexíveis que são observáveis nas imagens de alta resolução espacial. Esta última etapa faz uso intensivo das novas técnicas de classificação de imagens baseadas em objetos. O resultado final é a geração de índices da condição da superfície do pavimento a partir das imagens que possam ser comparados com os indicadores vigentes da condição da superfície do pavimento já normatizados pelos órgãos competentes no país. Abstract in english Monitoring every Brazilian road use condition is an expensive and time consuming task. This research deals with new techniques which will yield a quick survey of road surface pavement condition by using hyperspectral images from airborne remote sensing. Recently, an increasing number of images with [...] high spatial resolution has emerged on the world market with the advent of new remote sensing satellites and airborne sensors. Hyperspectral images from digital airborne sensor have been used in this work. A new identification methodology for a pavement surface and also for classification of the main defects of the surface has been devised. The first step of the methodology is the identification of the asphalt surface in the image, by using hybrid classification based on pixel initially and then improved by objects. The second step of the methodology is the identification and classification of the main defects of pavement surface that are observable in high spatial resolution imagery. This step makes intensive use of new techniques for classification of images based on objects. The goal is the generation of pavement surface condition index from the images which can be compared to quality index of pavement surface already managed by the regulatory agency in the country.

  5. Formulação probabilística para análise de tabuleiros de pontes rodoviárias com irregularidades superficiais / Probabilistic formulation for the analysis of highway bridge decks with irregular pavement surface

    Scientific Electronic Library Online (English)

    José Guilherme Santos da, Silva; João Luís Pascal, Roehl.

    1999-09-01

    Full Text Available Apresenta-se uma metodologia de análise com o objetivo de avaliarem-se os efeitos de irregularidades superficiais no tabuleiro sobre o comportamento de pontes rodoviárias submetidas à passagem de veículos. A resposta do sistema veículo-estrutura é obtida no domínio da freqüência segundo modelo proba [...] bilístico. Simula-se o tabuleiro das pontes com modelo de elementos finitos unidimensionais com massas discretizadas nos nós, o veículo por um sistema de massas, molas e amortecedores, e as irregularidades da pista são definidas por modelo não-determinístico com base na densidade espectral do perfil do pavimento. O carregamento é constituído por uma sucessão infinita de veículos igualmente espaçados deslocando-se com velocidade constante sobre o tabuleiro e a atenção é concentrada na fase permanente da resposta do sistema. Deduzem-se as expressões das densidades espectrais dos elementos da resposta a partir da densidade espectral do perfil irregular do pavimento e integram-se numericamente tais expressões para se chegar às médias quadráticas desses elementos. Observa-se a resposta do modelo matemático, com base em uma ponte rodoviária de concreto armado simplesmente apoiada, com seção tipo caixão e inércia constante, em termos de deslocamentos e esforços nas seções onde ocorrem os efeitos máximos. As conclusões versam sobre a adequação da metodologia desenvolvida e do modelo matemático empregado. Abstract in english An analysis methodology is proposed to evaluate the dynamical effects, displacements and stresses, on highway bridge decks, due to vehicles crossing on the rough pavement surfaces defined by a probabilistic model. To this purpose, the methodology is developed to evaluate the vehicle-structure respon [...] se under a full probabilistic formulation, running in the frequency domain. The mathematical model assumes a finite element representation of the beam like deck and the vehicle simulation uses concentrated parameters of mass, stiffness and damping. The deck surface roughness is defined by a well known power spectrum density of road pavement profiles. The moving load is formed by an infinite succession of equally spaced vehicles moving with constant velocity. Only steady-state response is considered. Response data are produced on concrete box girder elements assembled as a simple beam. Conclusions are concerned with the fitness of the developed analysis methodology and the mathematical model adequacy.

  6. Formulação probabilística para análise de tabuleiros de pontes rodoviárias com irregularidades superficiais Probabilistic formulation for the analysis of highway bridge decks with irregular pavement surface

    Directory of Open Access Journals (Sweden)

    José Guilherme Santos da Silva

    1999-09-01

    Full Text Available Apresenta-se uma metodologia de análise com o objetivo de avaliarem-se os efeitos de irregularidades superficiais no tabuleiro sobre o comportamento de pontes rodoviárias submetidas à passagem de veículos. A resposta do sistema veículo-estrutura é obtida no domínio da freqüência segundo modelo probabilístico. Simula-se o tabuleiro das pontes com modelo de elementos finitos unidimensionais com massas discretizadas nos nós, o veículo por um sistema de massas, molas e amortecedores, e as irregularidades da pista são definidas por modelo não-determinístico com base na densidade espectral do perfil do pavimento. O carregamento é constituído por uma sucessão infinita de veículos igualmente espaçados deslocando-se com velocidade constante sobre o tabuleiro e a atenção é concentrada na fase permanente da resposta do sistema. Deduzem-se as expressões das densidades espectrais dos elementos da resposta a partir da densidade espectral do perfil irregular do pavimento e integram-se numericamente tais expressões para se chegar às médias quadráticas desses elementos. Observa-se a resposta do modelo matemático, com base em uma ponte rodoviária de concreto armado simplesmente apoiada, com seção tipo caixão e inércia constante, em termos de deslocamentos e esforços nas seções onde ocorrem os efeitos máximos. As conclusões versam sobre a adequação da metodologia desenvolvida e do modelo matemático empregado.An analysis methodology is proposed to evaluate the dynamical effects, displacements and stresses, on highway bridge decks, due to vehicles crossing on the rough pavement surfaces defined by a probabilistic model. To this purpose, the methodology is developed to evaluate the vehicle-structure response under a full probabilistic formulation, running in the frequency domain. The mathematical model assumes a finite element representation of the beam like deck and the vehicle simulation uses concentrated parameters of mass, stiffness and damping. The deck surface roughness is defined by a well known power spectrum density of road pavement profiles. The moving load is formed by an infinite succession of equally spaced vehicles moving with constant velocity. Only steady-state response is considered. Response data are produced on concrete box girder elements assembled as a simple beam. Conclusions are concerned with the fitness of the developed analysis methodology and the mathematical model adequacy.

  7. Pavement Evaluation and Maintenance Decisions Based on Fuzzy Inference Systems

    Directory of Open Access Journals (Sweden)

    Beltrán-Calvo Gloria Inés

    2014-07-01

    Full Text Available The remaining service life and maintenance decisions of existing pavements are highly dependent on stiffness and deterioration conditions throughout their operation. A non-conventional fuzzy logic based methodology is proposed in this work to address the stiffness-deterioration condition and conservation decisions, by means of three Fuzzy Inference Systems. Analysis were conducted using a database gathered from field tests performed on three and four layer pavement systems, that included traditional layer structuring and pavements having a subbase stiffer than their granular base. Information about layer thicknesses, magnitude and severity of structural distresses, and parameters and indicators derived from deflection testing by impulse load devices were used. The developed systems, allowed representing expert knowledge and linguistic variables of subjective and qualitative nature, commonly used to describe the severity levels of deterioration; thus they can be involved into structural characterization of pavements. Results were also expressed linguistically, to facilitate their interpretation and understanding. Based on the high quality of results obtained, it seems reasonable to conclude that the proposed systems could be used confidently for assessing and making decisions about pavement conservation, with low computational cost.

  8. Dynamic pavement deflection

    Science.gov (United States)

    Rand, D. W.; Jacobs, K. M.

    1981-06-01

    Dynamic pavement deflection measurements for bituminous concrete pavements of two and three-quarter, five and seven-eights, and seven and one-half inches in thickness under moving axle loads of 15,000, 18,000, and 22,000 pounds were obtained at speeds of 10, 25 and 45 miles per hour. The results were analyzed and compared to Benkelman beam measurements. The data indicate that slow moving loads have greater adverse effect (larger deflections) on the pavement than the high speed loads. The results also show that the bituminous pavement undergoes numerous vertical fluctuations and bending as the front and rear axles approached the point of measurement. The magnitude of the vertical displacement was measured via the means of an accelerometer and double integrator. When values of the dynamic deflections were in the magnitude of 0.07 through 0.10 inches, there was evidence of pavement failure. When the deflection values were above 0.10 inches pavement failures were distinct.

  9. The impact of geology on the performance of a bituminous surfaced pavement—a case study from southeastern Nigeria

    Science.gov (United States)

    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.

  10. A real-time 3D scanning system for pavement distortion inspection

    International Nuclear Information System (INIS)

    Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement

  11. Improvement of the functional pavement quality with asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane P. T. L.; Pereira, Paulo A. A.; Pais, Jorge C.; Trichês, Glicério

    2006-01-01

    Skid resistance and texture are important safety characteristics which need to be considered in flexible pavement design, maintenance and rehabilitation. The main objective of this paper is to optimize surface texture characteristics in asphalt rubber pavements, mainly macrotexture to reduce splash, spray and hydroplaning and microtexture to increase friction at low and high speeds. The objective was accomplished by measuring the friction surface with two different tests: (i) B...

  12. Road Asphalt Pavements Analyzed by Airborne Thermal Remote Sensing: Preliminary Results of the Venice Highway

    OpenAIRE

    Rosa Cavalli; Maurizio Poscolieri; Angelo Palombo; Cristiana Bassani; Simone Pascucci

    2008-01-01

    This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strict...

  13. Subsurface defect detection in first layer of pavement structure and reinforced civil engineering structure by FRP bonding using active infrared thermography

    Science.gov (United States)

    Dumoulin, Jean; Ibos, Laurent

    2010-05-01

    In many countries road network ages while road traffic and maintenance costs increase. Nowadays, thousand and thousand kilometers of roads are each year submitted to surface distress survey. They generally lean on pavement surface imaging measurement techniques, mainly in the visible spectrum, coupled with visual inspection or image processing detection of emergent distresses. Nevertheless, optimisation of maintenance works and costs requires an early detection of defects within the pavement structure when they still are hidden from surface. Accordingly, alternative measurement techniques for pavement monitoring are currently under investigation (seismic methods, step frequency radar). On the other hand, strengthening or retrofitting of reinforced concrete structures by externally bonded Fiber Reinforced Polymer (FRP) systems is now a commonly accepted and widespread technique. However, the use of bonding techniques always implies following rigorous installing procedures. To ensure the durability and long-term performance of the FRP reinforcements, conformance checking through an in situ auscultation of the bonded FRP systems is then highly suitable. The quality-control program should involve a set of adequate inspections and tests. Visual inspection and acoustic sounding (hammer tap) are commonly used to detect delaminations (disbonds) but are unable to provide sufficient information about the depth (in case of multilayered composite) and width of debonded areas. Consequently, rapid and efficient inspection methods are also required. Among the non destructive methods under study, active infrared thermography was investigated both for pavement and civil engineering structures through experiments in laboratory and numerical simulations, because of its ability to be also used on field. Pulse Thermography (PT), Pulse Phase Thermography (PPT) and Principal Component Thermography (PCT) approaches have been tested onto pavement samples and CFRP bonding on concrete samples in laboratory. In parallel numerical simulations have been used to generate a set of time sequence of thermal maps for simulated samples with and without subsurface defect. Using this set of experimental and simulated data different approaches (thermal contrast, FFT analysis, polynomial interpolation, singular value decomposition…) for defect location have been studied and compared. Defect depth retrieval was also studied on such data using different thermal model coupled to a direct or an inverse approach. Trials were conducted both with an uncooled and cooled infrared camera with different measurement performances. Results obtained will be discussed and analysed in the paper we plan to present. Finally, combining numerical simulations and experiments allows us discussing on the sensitivity influence of the infrared camera used to detect subsurface defects.

  14. Modelling of the interaction component's of recycled hot mix asphalt and research its use in the road pavement construction

    OpenAIRE

    Mu?inis, Darjušas

    2012-01-01

    The purpose of the dissertation is to provide a science-based model of the interaction dynamics among the components and the results of this interaction, which shall help to design and to produce high quality hot-mix asphalt mixtures with granules of recycled asphalt pavement of Lithuanian roads. The main objectives of the dissertation: – To conduct the research, to collect, systemized and analyzed scientific works discussing the factors of asphalt pavement distresses and their influence on t...

  15. Modeling Deflection Basin Using Neurofuzzy in Backcaluculating Flexible Pavement Layer Moduli

    Directory of Open Access Journals (Sweden)

    Mehmet Saltan

    2002-01-01

    Full Text Available Flexible pavement surface condition date play a principle role in the evaluation of pavement structural capacity and in the design of pavement rehabilitation programs. Flexible pavements are affected by moving vehicles, climate and other environmental factors. As a result of these factors, the pavement starts to deteriorate. In order to prevent further deterioration, a maintenance program should be carried out at right time and right places. For the determination of the structural carrying capacity of the pavement, non-destructive testing equipments are used. In such a process, the most important thing is to analyse the collected data. A backcalculation procedure is carried out for back-calculation elastic modules for each layer effective in the pavement life. The input data are usually restricted to the pavement surface deflection or its basin obtained by Nondestructive testing as the Falling Weight Deflectometer (FWD. Generally, linear elastic and finite element based programs are used for back-calculating, but they are both time consuming. It is also important to simulate deflection basin realistically in backcalculating pavement layer moduli. For this purpose, NeuroFuzzy method is used for simulation deflection basin during the course of this study. Results indicate that the NeuroFuzzy can be used for backcalculation of flexible pavement layer moduli with great improvement and accuracy.

  16. Pavement Snow Melting

    Energy Technology Data Exchange (ETDEWEB)

    Lund, John W.

    2005-01-01

    The design of pavement snow melting systems is presented based on criteria established by ASHRAE. The heating requirements depends on rate of snow fall, air temperature, relative humidity and wind velocity. Piping materials are either metal or plastic, however, due to corrosion problems, cross-linked polyethylene pipe is now generally used instead of iron. Geothermal energy is supplied to systems through the use of heat pipes, directly from circulating pipes, through a heat exchanger or by allowing water to flow directly over the pavement, by using solar thermal storage. Examples of systems in New Jersey, Wyoming, Virginia, Japan, Argentina, Switzerland and Oregon are presented. Key words: pavement snow melting, geothermal heating, heat pipes, solar storage, Wyoming, Virginia, Japan, Argentina, Klamath Falls.

  17. The impact of material characteristics on tire pavement interaction noise for flexible pavements

    Science.gov (United States)

    Kocak, Salih

    Noise pollution has recently been one of the growing problems all over the world. While there are many sources of the noise, traffic noise is the main contributor to the total environmental noise. Although there are different sources for traffic noise, the tire pavement interaction noise is the most dominant component within most city and highway limits. One of the ways to reduce the tire pavement noise is to improve the material characteristics of the pavements such that they produce less noise. In this study, the relationship between basic material characteristics (e.g., Hot Mix Asphalt (HMA) volumetrics) and sound generation and absorption characteristics of flexible pavements was investigated. In addition, the effect of linear visco-elastic properties (e.g., dynamic modulus (|E*|) and phase angle (delta)) on sound absorption was studied. In order to focus only on impact of material characteristics and overshadow the effect of surface texture, a novel laboratory tire pavement noise measurement simulator (TIPANOS) was developed. The statistical analysis results showed that although the individual material characteristics do not have appreciable influence on sound absorption, there is a significant correlation between sound pressure levels (SPL) and combination of several material and linear visco-elastic parameters.

  18. A model for the pavement temperature prediction at specified depth using neural networks

    Directory of Open Access Journals (Sweden)

    B. Mati?

    2014-10-01

    Full Text Available Earlier researches have established that the ambient temperature is one of the most important factors for pavement temperature analysis.This paper examines the existing models for predicting pavement temperatures at specified depth and formulates a new one using neural networks depending on the surface pavement temperature and depth. It was also conducted the validation of the model comparing predicted with measured temperatures.

  19. Predicting in-service fatigue life of flexible pavements based on accelerated pavement testing

    Science.gov (United States)

    Guo, Runhua

    Pavement performance prediction in terms of fatigue cracking and surface rutting are essential for any mechanistically-based pavement design method. Traditionally, the estimation of the expected fatigue field performance has been based on the laboratory bending beam test. Full-scale Accelerated Pavement Testing (APT) is an alternative to laboratory testing leading to advances in practice and economic savings for the evaluation of new pavement configurations, stress level related factors, new materials and design improvements. This type of testing closely simulates field conditions; however, it does not capture actual performance because of the limited ability to address long-term phenomena. The same pavement structure may exhibit different response and performance under APT than when in-service. Actual field performance is better captured by experiments such as Federal Highway Administration's Long-Term Pavement Performance (LTPP) studies. Therefore, to fully utilize the benefits of APT, there is a need for a methodology to predict the long-term performance of in-service pavement structures from the results of APT tests that will account for such differences. Three models are generally suggested to account for the difference: shift factors, statistical and mechanistic approaches. A reliability based methodology for fatigue cracking prediction is proposed in this research, through which the three models suggested previously are combined into one general approach that builds on their individual strengths to overcome some of the shortcomings when the models are applied individually. The Bias Correction Factor (BCF) should account for all quantifiable differences between the fatigue life of the pavement site under APT and in-service conditions. In addition to the Bias Correction Factor, a marginal shifty factor, M, should be included to account for the unquantifiable differences when predicting the in-service pavement fatigue life from APT. The Bias Correction Factor represents an improvement of the currently used "shift factors" since they are more general and based on laboratory testing or computer simulation. By applying the proposed methodology, APT performance results from a structure similar to an in-service structure can be used to perform four-point bending beam tests and structural analysis to obtain an accurate estimate of the necessary Bias Correction Factor to estimate in-service performance.

  20. The study of road surface micro-texture's effects for the pavement's decontamination by high pressure water washing

    International Nuclear Information System (INIS)

    In the result of “decontamination technical demonstration project” by Ministry of the Environment, it has became clear that the effect variation is larger in high pressure water washing method, compared with others in road surface decontamination technology. In this study, we have hypothesized the fact at the difference of micro-texture of the road surface, by carrying out high pressure water washing method in different kinds of road surfaces and verified the relation between washing efficiency and micro-texture road surface. Positive correlation has admitted between the washing number of times and radiation reduction rate and the trend of primary regression equation (i.e. radiation reduction rate per washing time) is indicating that decreasing tendency of radiation carried by the increasing of micro-texture of the road surface. Here, we proposed the method to estimated essential washing number of times to achieve the targeted radiation reduction rate from the relation of that trend and micro-texture of the road surface. (author)

  1. POROUS PAVEMENT: RESEARCH; DEVELOPMENT; AND DEMONSTRATION

    Science.gov (United States)

    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...

  2. Pervious Pavement System Evaluation

    Science.gov (United States)

    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...

  3. Acute respiratory distress syndrome

    Science.gov (United States)

    Herridge MS. Recovery and long-term outcome in acute respiratory distress syndrome. Crit Care Clin . 2011;27:685–704. Lee WL, Slutsky AS. Acute respiratory distress syndrome. In: Mason RJ, Murray JF, Broaddus VC, ...

  4. Neonatal respiratory distress syndrome

    Science.gov (United States)

    Hyaline membrane disease; Infant respiratory distress syndrome (IRDS); Respiratory distress syndrome in infants; RDS - infants ... breathing machine in many babies. CPAP uses a device that sends air into the nose to help ...

  5. Impact of Vehicle Class and Tire Pressure on Pavement Performance in MEPDG

    Directory of Open Access Journals (Sweden)

    Mohamed I. E. Attia

    2014-10-01

    Full Text Available The new Mechanistic-Empirical Pavement Design Guide (MEPDG design and analysis procedures defines the exact traffic loading by defining the specific number of each vehicle class and the use of axle load distribution factors instead of the equivalent single axle load (ESAL. The number of traffic inputs (parameters in MEPDG was found to be 17024. This research aimed to evaluate the sensitivity of the predicted flexible pavement distress to vehicle class and tire pressure in MEPDG. To evaluate the impact of vehicle (truck class on pavement sections, different cases of loading were analyzed. For each case, the MEPDG Ver. 1.1 was used to evaluate the effect of tire pressure by solving each case for a tire pressure of 120 and 140 psi. The effect of the traffic parameters on asphalt pavement (AC rutting, base rutting, subgrade rutting, international roughness index (IRI, longitudinal cracking and fatigue (alligator cracking were investigated. It was found that vehicle class distribution (VCD would cause clear impact (comparable to the effect of AADTT level only if the major traffic is of specific class (very light or very heavy. If this is not the case, the vehicle class distribution will not be a significant factor that affects the final design because most of the trucks had similar impact on flexible pavement distresses. The impact of tire pressure is clear on longitudinal cracking, fatigue cracking and AC rutting, and have no significant impact on both base and subgrade rutting.

  6. Comparative Study on Pavement Temperature Features of Bridge Deck and Road Pavement

    OpenAIRE

    Yueqin Hou; Nanxiang Zheng; Yiluo Zhang

    2013-01-01

    The objective of this study was to comparatively analyze the difference of pavement temperature of bride deck and road pavement. The asphalt pavement temperature of road pavement and bride deck were tested in Guozigou area of Xinjiang, China. And the air temperature, wind speed, humidness and sunlight radiation were collected. Further, the distribution features of asphalt pavement of bridge deck and road pavement were comparatively analyzed. At last, the predictive model of pavement temperatu...

  7. Towards noise classification of road pavements

    OpenAIRE

    Freitas, Elisabete F.; Paulo, Joel; Coelho, J. L. Bento; Pereira, Paulo A. A.

    2008-01-01

    Noise classification of road surfaces has been addressed in many European countries. This paper presents the first approach towards noise classification of Portuguese road pavements. In this early stage, it aims at establishing guidelines for decision makers to support their noise reduction policies and the development of a classification system adapted to the European recommendations. A ranking to provide guidance on tire-road noise emission levels for immediate use by decisio...

  8. Urban evaporation rates for water-permeable pavements.

    Science.gov (United States)

    Starke, P; Göbel, P; Coldewey, W G

    2010-01-01

    In urban areas the natural water balance is disturbed. Infiltration and evaporation are reduced, resulting in a high surface runoff and a typical city climate, which can lead to floods and damages. Water-permeable pavements have a high infiltration rate that reduces surface runoff by increasing the groundwater recharge. The high water retention capacity of the street body of up to 51 l/m(2) and its connection via pores to the surface lead to higher evaporation rates than impermeable surfaces. A comparison of these two kinds of pavements shows a 16% increase in evaporation levels of water-permeable pavements. Furthermore, the evaporation from impermeable pavements is linked directly to rain events due to fast-drying surfaces. Water-permeable pavements show a more evenly distributed evaporation after a rain event. Cooling effects by evaporative heat loss can improve the city climate even several days after rain events. On a large scale use, uncomfortable weather like sultriness or dry heat can be prevented and the urban water balance can be attenuated towards the natural. PMID:20818060

  9. Toward the acoustical characterization of asphalt pavements: analysis of the tire/road sound from a porous surface.

    Science.gov (United States)

    Paje, S E; Bueno, M; Viñuela, U; Terán, F

    2009-01-01

    Sound level in close proximity to the contact patch of the tire and road (L(CPtr)) is analyzed as a function of the vehicle speed in the acoustic frequency range, showing different behavior depending on frequency. At least two regions are observed; one at low frequencies, where the variation in sound with speed (coefficient B) increases with frequency, and the other at higher frequencies, where such sound/speed variation does not increase significantly with frequency. The dependence of B at low frequencies seems to be correlated with the high sound absorption of this porous surface. PMID:19173385

  10. Use of accelerated aging to predict behavior of recycled materials in concrete pavements. Physical and environmental comparison of laboratory-aged samples with field pavements

    Energy Technology Data Exchange (ETDEWEB)

    Van der Sloot, H.A. [ECN Clean Fossil Fuels, Petten (Netherlands); Eighmy, T.T.; Cook, R.A.; Gress, D.L.; Coviello, A.; Spear, J.C.M. [University of New Hampshire, Durham, NH (United States); Hover, K.; Pinto, R.; Hobbs, S. [Cornell University, Ithaca, NY (United States); Kosson, D.S.; Sanchez, F. [Vanderbilt University, Nashville, TN (United States); Korhonen, C. [US Army Corps of Engineers Cold Regions Research and Engineering Laboratory, Hanover, NH (United States); Simon, M. [Turner-Fairbank Highway Research Center, McLean, VA (United States)

    2002-11-01

    Future behavior of recycled materials in highway applications is often difficult to predict. Accelerated aging is one means of exploring the long-term physical and environmental performance. Coal fly ash (CFA), routinely used as a cementitious replacement in portland cement concrete pavement, was selected as a model system in an accelerated aging approach. US-20 near Fort Dodge, Iowa, was used as a source of field-aged pavement slab material and concrete mixture proportions. This pavement, constructed in 1987, experienced early failure and distress. The role of CFA, if any, in the failure is not known. Three types of accelerated aging treatments were chosen and applied on laboratory prisms made with the US-20 mixture proportions: arrhenius ageing (AA), cyclic loading, and freeze-thaw exposure. Physical and environmental response variables were used to examine the pavement slab and the aged laboratory prisms. The aging protocol affected both physical and chemical properties of the monoliths. It took about 9 months of elapsed time to age specimens to an equivalent age of about 4 years. The equivalent ages matched well with the time frame seen in the field for the onset of early distress. Most response variables for the aged laboratory prisms and the field samples were similar, suggesting that the aging method reasonably produced a pavement of similar age and distress. The AA treatment produced an unexpected loss of strength, suggesting that the accelerated aging promoted the onset of a deleterious reaction. Distinguishing the source of trace metals in leachates was difficult, for all components (CFA, aggregates, cement) had similar elemental compositions and leachability. The use of both physical and environmental response variables showed linkages between compressive strength, microcracking, fine pore structure, Cl diffusive leaching (efflux related to road slating that increases the concentration of Cl in the monolith), and Ca diffusive leaching (related to change in matrix structure and loss of Ca)

  11. Experimental studies of the dilution of vehicle exhaust pollutants by environment-protecting pervious pavement.

    Science.gov (United States)

    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

  12. Photocatalytic pavement blocks. Air purification by pavement blocks. Final results of the research at BRRC

    International Nuclear Information System (INIS)

    The use of materials can influence to a large extent the environmental impact of traffic and of road infrastructure. Especially in urban areas, where the risk on smog formation during hot summer days is high, the use of photocatalytic pavement blocks can reduce the air pollution significantly. A project on environmental friendly concrete pavement blocks is conducted at the Belgian Road Research Centre. The use of photocatalytic material in the surface of pavement blocks to obtain air purifying materials is investigated. In contact with light, TiO2 as photocatalyst, is able to reduce the NO and NO2 content in the air, caused by the exhaust of traffic. The efficiency is tested on pavement blocks, but the technique can as well be applied on other road elements (e.g. noise reducing walls, linear elements) or as a coating on new materials or existing structures. At the previous TRA conference in Gotenborgh, Sweden, the principle of photocatalysis was presented. In this paper, emphasis will be put on the final results of the 4-year project obtained in laboratory as well as on site at the Leien of Antwerp (10,000 m2). The results indicate a durable efficiency towards NOx reduction, which is in favour for the diminishing of the risk on ozone formation. However, the precise translation from the laboratory towards the site is still in question. The results obtained during the project are discussed in this paper

  13. Measuring Clogging with Pressure Transducers in Permeable Pavement Strips

    Science.gov (United States)

    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...

  14. Pavement Subgrade Performance Study : Part II: Modeling Pavement Response and Predicting Pavement Performance

    DEFF Research Database (Denmark)

    Zhang, Wei; Ullidtz, Per

    1998-01-01

    The report describes the second test in the Danish Road Testing Machine (RTM) under the International Pavement Subgrade Performance Study. Pavement response was measured in different layers, and compared to different theroretical values. Performance in terms of plastic strains, rutting and roughness was measured and theoretical prediction models were developed.

  15. Nondestructive testing of pavements and pavement bases (a bibliography with abstracts). Report for 1964--Dec 1975

    International Nuclear Information System (INIS)

    Eighty references on nondestructive methods for quality assurance of pavements and pavement bases are presented. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed

  16. Measurements of the Stiffness and Thickness of the Pavement Asphalt Layer Using the Enhanced Resonance Search Method

    OpenAIRE

    Nur Mustakiza Zakaria; Nur Izzi Md. Yusoff; Sentot Hardwiyono; Khairul Anuar Mohd Nayan; Ahmed El-Shafie

    2014-01-01

    Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic paveme...

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

    Science.gov (United States)

    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

  18. Analysis of Pavement for National Highway-N.H.1

    Directory of Open Access Journals (Sweden)

    Arvind Dewangan

    2012-02-01

    Full Text Available Rigid pavements are those which posses note worthy flexural strength or flexural rigidity. The stresses are not transferred from grain to grain to the lower layers as in the ease of flexible pavements layers the rigid pavements are made of Portland cement concrete-either plain, reinforced or prestressed concrete[1]. This paper shows the required to evaluate the strength characteristics of the soil subgrade, this helps the designer to adopt the suitable values of the strength parameter for design purposes and in case this supporting layer does not come upto the expectations, the same is treated or conditioned to suit the requirementsThe plain cement concrete slabs are expected to take up about 40 kg/cm2 flexural stress. As the rigid pavements slab has tensile strength, tensile stresses are developed due to the bending of the slab under wheel load and temperature variations thus the type of stress develop and their distribution within the cement concrete slab are quit different. The rigid pavement does not get deformed to the shape of the lower surface as it can bridge the minor variation of lower layer[2].

  19. Mechanical impedance and CPX noise of SMA pavements

    OpenAIRE

    Va?zquez, V. F.; Paje, S. E.

    2012-01-01

    CPX noise is the sound measured in close proximity to the tyre/pavement contact patch when a vehicle is rolling. The mechanical impedance or dynamic stiffness of the pavement is one of the factors involved in the generation of this type of noise. The reduction of the impact noise generation mechanism can be achieved with the construction of mixtures with lower dynamic stiffness. On the other hand, SMA mixtures, widely used in Europe, have come into use recently in Spain as a surface layer. Th...

  20. Development of Performance Models for a Typical Flexible Road Pavement in Nigeria

    Directory of Open Access Journals (Sweden)

    Adebayo Oladipo Owolabi

    2012-09-01

    Full Text Available The results of a study conducted to facilitate the development of road pavement performance models that are appropriate for Nigeria and similar developing countries andcould predict the rate of deterioration over their lifespan have been presented. Comprehensive investigations were carried out on the expressway linking Lagos (the economic nerve centre of Nigeria with Ibadan (the largest city in West Africa - apparently one of the most heavily trafficked roads in the country. Data relating to traffic characteristics, pavement condition ratings, distress types, pavement thickness, roughness index, rainfall and temperature, were collected. Models were developed to determine Pavement Condition Score (PCS and International Roughness Index (IRI. Stepwise Regression was used to analyse the data and quantify the impact of key input parameters on the PCS and IRI. Parameters such as depth of ruts and area of pot holes were found to be statistically significant in predicting PCS while number of patches, length of longitudinal cracks and depth of ruts were statistically significant in predicting IRI. The models can be used for planning road maintenance programs, thus minimizing the need for comprehensive data collection on pavement condition before the maintenance exercise, which is costly and time consuming.

  1. Asphalt Pavement Deflection due to a Circular Load and Temperature Modified Coefficient

    Directory of Open Access Journals (Sweden)

    Hu Honglong

    2014-02-01

    Full Text Available This study proposed an approximate computation method of pavement deflection due to a circular and regression formulas among temperature modified coefficient to deflection, the average temperature of surface course and pavement structure parameters. Based on theoretical solution of pavement deflection which is beneath the center of the load due to a circular load applied on a homogeneous half-space, by introducing structure parameter modified coefficient &zeta, approximate computation method of pavement deflection due to a circular applied to a two-layer or multilayer pavement was given. Most regression formulas of temperature modified coefficient to deflection were dependent of testing data, we studied on influence factors of temperature modified coefficient to deflection from a theoretical view and then established an approximate formula among modified coefficient K, the average temperature of surface course T and pavement structure parameters are then established. The results show that temperature modified coefficient to deflection was dependent of the average temperature of surface course and pavement structure parameters. The calculation results using regression formulas in this study can be satisfied with engineering precision requirements.

  2. Pervious Pavement System Evaluation-Poster

    Science.gov (United States)

    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...

  3. Recycling of Asphalt Pavements with Asphalt Rubber

    OpenAIRE

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Baptista, Anto?nio

    2008-01-01

    Pavement recycling has been an important rehabilitation technique to deal with reclaimed materials from old pavements which are usually sent to landfills. The application of this technique contributes to: i) the accomplishment of the requirements defined by the European legislation for the amount of material sent to landfills; ii) the reduction in the use of new raw materials used to produce pavement layers. The reduction of materials to be used in pavement rehabilitation has also been possib...

  4. Pavement recycling : an environmentally sustainable rehabilitation alternative

    OpenAIRE

    Oliveira, Joel; Silva, Hugo Manuel Ribeiro Dias Da; Pereira, Paulo A. A.

    2007-01-01

    The preservation of environment by reducing the use of material and natural resources together with important economic savings have led pavement recycling to be a prime solution for pavement maintenance/rehabilitation. It is based on sustainable development, by reusing materials reclaimed from the pavements and reducing the disposal of asphalt materials. The present paper focuses on the analysis of a heavily trafficked urban road rehabilitation project. The original pavement...

  5. Respiratory Distress Syndrome

    Science.gov (United States)

    ... that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Respiratory Distress Syndrome, visit www.clinicaltrials.gov . Visit Children ...

  6. Making "Magic" Sidewalks of Pervious Pavement

    Science.gov (United States)

    Water Awareness Research and Education (WARE) Research Experience for Teachers (RET),

    Students use everyday building materials—sand, pea gravel, cement and water—to 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.

  7. Pavement Subgrade Performance Study in the Danish Road Testing Machine

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ertman Larsen, Hans JØrgen

    1997-01-01

    Most existing pavement subgrade criteria are based on the AASHO Road Test, where only one material was tested and for only one climatic condition. To study the validity of these criteria and to refine the criteria a co-operative research program entitled the "International Pavement Subgrade Performance Study" was sponsored by the FHWA with American, Finnish and Danish partners. This paper describes the first test series which was carried out in the Danish Road Testing Machine (RTM).The first step in this program is a full scale test on an instrumented pavement in the Danish Road Testing Machine. Pressure gauges and strain cells were installed in the upper part of the subgrade, for measuring stresses and strains in all three directions. During and after construction FWD testing was carried out to evaluate the elastic parameters of the materials. These parameters were then used with the theory of elasticity to calculate the stresses and strains at the position of the gauges and to compare these values to the stresses and strains recorded under the rolling wheel load.Plastic strains resulting from 50 000 applications of each of two load levels (20 kN and 40 kN) were recorded, as well as the permanent deformation of the pavement surface. A simple model describing the plastic strain has been developed.The test showed that currently used subgrade strain criteria are conservative if used with the measured strains in the subgrade. If used with strains calculated from FWD tests using linear elastic theory, however, the strain criteria seem to give a reasonably good prediction of the bearing capacity of the pavement.The differences between measured and theoretical values appear to be due to inhomogeneities in the pavement, to the non-linear elastic subgrade modulus and to a modulus gradient in the subgrade.

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

    International Nuclear Information System (INIS)

    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 separn 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. (letter)

  9. Geo synthetic-reinforced Pavement systems

    International Nuclear Information System (INIS)

    Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

  10. Comparative Study on Pavement Temperature Features of Bridge Deck and Road Pavement

    Directory of Open Access Journals (Sweden)

    Yueqin Hou

    2013-12-01

    Full Text Available The objective of this study was to comparatively analyze the difference of pavement temperature of bride deck and road pavement. The asphalt pavement temperature of road pavement and bride deck were tested in Guozigou area of Xinjiang, China. And the air temperature, wind speed, humidness and sunlight radiation were collected. Further, the distribution features of asphalt pavement of bridge deck and road pavement were comparatively analyzed. At last, the predictive model of pavement temperature field for bridge deck and road pavement was set up. The results show that the pavement temperature and air temperature change synchronously. The pavement temperature of bridge deck is usually 66~13ºC higher than the air temperature and keeps close to it in winter. Compared with road pavement temperature, the temperature of bridge deck is characterized by being higher lowest-temperatures in winter, greater in temperature changes and lasting for longer time when it keeps its high temperature in summer. The predictive model of pavement temperature field for bridge deck and road pavement is proposed utilized linear function with five factors, namely air temperature, wind speed, humidness, sunlight radiation and pavement depth. The developed model was proved to be more accurate and closer to the measured temperature compared with LTPP and SHRP model.

  11. Superfícies estriadas no embasamento granítico e vestígio de pavimento de clastos neopaleozóicos na região de Salto, SP Neopaleozoic striated surfaces in the granitic basement and clast pavement remains of Salto, SP

    Directory of Open Access Journals (Sweden)

    Annabel Pérez-Aguilar

    2009-03-01

    Full Text Available Nas proximidades da Cerâmica Guaraú, localizada a sudoeste da cidade de Salto, Estado de São Paulo, dois afloramentos de granito, distantes algumas dezenas de metros um do outro, exibem superfícies estriadas neopaleozóicas. Essas superfícies estão em contato com diamictitos do Subgrupo Itararé. As estrias correspondem a sulcos subparalelos com espaçamento e profundidade milimétrica, possuindo uma direção média de N48°W e mergulhos variando entre 12° e 42° para SE. As feições observadas e a sua associação com diamictitos indicam uma origem por abrasão glacial devido ao movimento de massas de gelo de sudeste para noroeste. A aproximadamente 1,8 km a este da cidade de Salto foi encontrado, no topo de afloramentos de granito, material inconsolidado contendo abundantes clastos de quartzito facetados e estriados. Esses clastos foram interpretados como vestígios de um pavimento de castos.Near Guaraú Ceramic, localized southwest of Salto city in the State of São Paulo, two granite outcrops, distant some tens of meters from each other, display Neopaleozoic striated surfaces. These surfaces are in contact with diamictites from the Itararé Subgroup. The striae correspond to sub parallel grooves with millimetric spacing and depth, oriented about N48E and dipping 12° to 42° towards SE. Observed features and association with diamictites indicate an origin by glacial abrasion due to ice movement from southeast towards northwest. About 1.8 km east of Salto, unconsolidated material containing flat-iron-shaped and striated clasts was found on top of granite outcrops, interpreted as clast pavement remains.

  12. Cooler reflective pavements give benefits beyond energy savings: durability and illumination

    International Nuclear Information System (INIS)

    City streets are usually paved with asphalt concrete because this material gives good service and is relatively inexpensive to construct and maintain. We show that making asphalt pavements cooler, by increasing their reflection of sunlight, may lead to longer lifetime of the pavement, lower initial costs of the asphalt binder, and savings on street lighting and signs. Excessive glare due to the whiter surface is not likely to be a problem

  13. ICP experiments more durable pavements

    International Nuclear Information System (INIS)

    A new asphalts technology that will make more durable the pavement in the highways and roads of the cities of Colombia investigates the Colombian Institute of the Petroleum ICP. The project that will have important incidence in the solution of one of the main problems in the roads of cities like Bogota, is only one of the 35 investigation programs and application of new technologies that with relationship to the sector of the hydrocarbons and its influence branches the ICP advances. The investigation looks for to elevate the current average of useful life of the pavements, with that it would be reached a standard that has the developed countries in this field

  14. Statistical classification of road pavements using near field vehicle rolling noise measurements.

    Science.gov (United States)

    Paulo, Joel Preto; Coelho, J L Bento; Figueiredo, Mário A T

    2010-10-01

    Low noise surfaces have been increasingly considered as a viable and cost-effective alternative to acoustical barriers. However, road planners and administrators frequently lack information on the correlation between the type of road surface and the resulting noise emission profile. To address this problem, a method to identify and classify different types of road pavements was developed, whereby near field road noise is analyzed using statistical learning methods. The vehicle rolling sound signal near the tires and close to the road surface was acquired by two microphones in a special arrangement which implements the Close-Proximity method. A set of features, characterizing the properties of the road pavement, was extracted from the corresponding sound profiles. A feature selection method was used to automatically select those that are most relevant in predicting the type of pavement, while reducing the computational cost. A set of different types of road pavement segments were tested and the performance of the classifier was evaluated. Results of pavement classification performed during a road journey are presented on a map, together with geographical data. This procedure leads to a considerable improvement in the quality of road pavement noise data, thereby increasing the accuracy of road traffic noise prediction models. PMID:20968348

  15. Validation of theoretical models through measured pavement response

    DEFF Research Database (Denmark)

    Ullidtz, Per

    1999-01-01

    Most models for structural evaluation of pavements are of the analytical-empirical type. An analytical model, derived from solid mechanics, is used to calculate stresses or strains at critical positions, and these stresses or strains are then used with empirical relationships to predict pavement performance. The analytical models are based on a number of simplifications with respect to reality and must be verified experimentally.Different pressure gauges were installed in a sand, assumed to be a semi-infinite halfspace. The surface of the sand was loaded by a Falling Weight Deflectometer (FWD) at different lateral positions with respect to the gauges. An integration of the stresses measured at the plane of the gauges showed that the total load recorded by the gauges was close to the loade imposed by the FWD, cofirming the reliability of the gauges. The theoretical stress calculated using continuum mechanics was quite different from the measured stress, the peak theoretical value being only half of the measured value.On an instrumented pavement structure in the Danish Road Testing Machine, deflections were measured at the surface of the pavement under FWD loading. Different analytical models were then used to derive the elastic parameters of the pavement layeres, that would produce deflections matching the measured deflections. Stresses and strains were then calculated at the position of the gauges and compared to the measured values. It was found that all analytical models would predict the tensile strain at the bottom of the asphalt layer reasonably well, but that the vertical strain at the top of the subgrade could only be predicted with some degree of accuracy if the subgrade was treated as a non-linear elastic material.

  16. Preliminary evaluation of the lifecycle costs and market barriers of reflective pavements; TOPICAL

    International Nuclear Information System (INIS)

    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 fellt-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

  17. Effects of thermal properties on temperature and moisture profiles and the performance of PCC pavements

    Directory of Open Access Journals (Sweden)

    Upender Kodide M.S.

    2011-12-01

    Full Text Available To understand the effects of thermal properties on temperature and the moisture profile in Portland cement concrete (PCC pavements, an Enhanced Integrated Climatic Model (EICM analysis was performed for a typical PCC pavement section in Louisiana. The EICM analysis showed that the temperature in the middle layer of PCC pavement decreased as thermal conductivity increased, and the temperature remained constant for higher thermal conductivity values. Temperature was measured at several depths of a concrete block embedded in soil and was compared to the temperature profile predicted by the EICM. Measured temperatures inside the concrete block were higher than the temperatures predicted by the EICM. The measured temperatures reached a peak hour temperature gradient on the hottest time of day, but the EICM model did not predict the peak hour temperature gradient. MEPDG analysis was performed to estimate the effect of thermal properties on the distress of PCC pavements. From the analysis it was found that thermal cracking increased with the decrease of thermal conductivity. It was also noticed that an Integrated Climatic Model (ICM stability failure occurred for a set of thermal conductivity and heat capacity readings in the MEPDG analysis. A passing line is proposed to separate the ICM stability passing zone and failure zone.

  18. The Concrete and Pavement Challenge

    Science.gov (United States)

    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. Modeling the Deflection Basin of Flexible Highway Pavements by Gene Expression Programming

    Directory of Open Access Journals (Sweden)

    Serdal Terzi

    2005-01-01

    Full Text Available In this study, Gene Expression Programming (GEP is used in modeling the deflection basins measured on the surface of the flexible pavements. Backcalculation of the pavement layer moduli are well-accepted procedures for the evaluation of the structural capacity of pavements. The ultimate aim of the backcalculation process from Nondestructive Testing (NDT results is to estimate the pavement material properties. Using backcalculation analysis, in situ material properties can be backcalculated from the measured field data through appropriate analysis techniques. In order to backcalculate reliable moduli, deflection basin must be realistically modeled. In this study, GEP was used to model the deflection basin characteristics. Experimental deflection data groups from NDT are used to show the capability of the GEP approach in modeling the deflection bowl. This approach can be easily and realistically performed to solve the problems which do not have a formulation or function about the solution.

  20. Girls in Distress in Israel.

    Science.gov (United States)

    Steiner, Yosepha

    The typical girl in distress in Israel comes from a Jewish family of oriental origin. Her distress is partially due to the strains of immigrating to Israel from, in most cases, North Africa. Authority models in distressed girls' families feature either the role of the father as the commanding familial authority figure; the mother as the dominant…

  1. Adult respiratory distress syndrome

    International Nuclear Information System (INIS)

    Our present-day knowledge concerning the clinico-chemical and radiological findings in adult respiratory distress syndrome are described. Three typical case histories have been selected to illustrate this condition; they were due to multiple trauma or sepsis. It is stressed that radiology is in a key position for making the diagnosis and for observing the course of the illness. (orig)

  2. Response of desert pavement to seismic shaking, Hector Mine earthquake, California, 1999

    Science.gov (United States)

    Haff, P. K.

    2005-06-01

    The October 1999 Mw 7.1 Hector Mine earthquake in the Mojave Desert, California, generated characteristic surface disturbances on nearby desert pavements. These disturbances included (1) zones of wholesale gravel displacement interspersed with zones of intact pavement, (2) displaced and rotated cobbles, (3) moats around loosened, embedded boulders, (4) filling of abandoned cobble sockets, boulder moats, and other depressions with gravel, and (5) formation of narrow, subparallel, linear strips of exposed fine-grained subpavement matrix (matrix lineations). Clasts displaced from matrix lineations and from cobble sockets tended to move downslope. Sharp boundaries of matrix lineations and slope-controlled displacement directions on slopes of only a few degrees indicated that clasts remained close to the pavement surface during shaking. The regular, few decimeter spacing of matrix lineations suggests the presence of standing waves during seismic shaking. Boulder moats probably have good preservation potential and, at some desert pavement locations, might provide information on paleoseismic shaking. Although readily produced by coseismic shaking, displaced cobbles are unreliable indicators of past earthquake activity because of potential multiple origins. For an assumed earthquake recurrence interval of 10 ka, seismically driven sediment fluxes similar to those generated by the Hector Mine earthquake at the Lavic Siding pavement study site may be marginally competitive with aseismic smoothing mechanisms driven by bioturbation, rainbeat, and wash. For a 1 ka recurrence interval, seismic smoothing is likely to play a significant role in pavement evolution.

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

    Science.gov (United States)

    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

  4. Runoff on Pavements of Soil-Cement Blocks – an Experimental Boarding

    Directory of Open Access Journals (Sweden)

    Zegarra-Tarqui Jorge Luis

    2015-01-01

    Full Text Available The article evaluates the reduction of runoff in pavements constructed with rectangular blocks of soil-cement. The tests were conducted in a pilot pavement built with soil-cement blocks, seated in a metal box of 50 cm × 50 cm (area = 2500 cm2, with declivities of 1%, 3% and 5%. Mean intensities of 76.9 mm / I 117.7 mm / h were used, values close to the intensities calculated by intensity-frequency-duration (i-f- -d equation of the city of Salvador, Brazil, for return periods of 2 and 5 years, respectively. The medium runoff coefficient was C = 0.61, this value is close to the coefficient of pavement with rectangular blocks (C = 0.6 and it has a lower value than the coefficient for concrete block pavement (C = 0.78. On the other hand, considering that areas with more than 2500 cm2 are constituted by coupling of area units of 50 cm × 50 cm, the splash losses are part of the runoff, obtaining the coefficient Csuperficial + splashing, which showed values in the 0.74 to 0.89 range, these values were found close to the coefficient of concrete block pavement (C = 0.78 and below the concrete pavement (C = 0.95, respectively, but factors such as displacement time of runoff on surface, depressions on the surface, roughness of pavement, evaporation and others, should reduce this value. Then, the pavement of soil-cement blocks can be considered in the category of semi-permeable for the area size used.

  5. Removable Urban Pavements: An innovative, sustainable technology

    OpenAIRE

    Larrard, Franc?ois; Sedran, Thierry; Balay, Jean Maurice

    2012-01-01

    Removable Urban Pavements: An innovative, sustainable technology By definition, a Removable Urban Pavement (RUP) can be quickly opened and closed, using lightweight equipment, for easy access to underground networks. While no such pavement appears to have ever been constructed, the premises of the concept can be found in certain military paths or industrial soils. A survey conducted among French municipal authorities has revealed the potential benefit of the RUP concept in decreasing the publ...

  6. ELLPAG - Economics of Long-Life Pavement

    OpenAIRE

    Bueche, N.

    2008-01-01

    One of the most important research efforts developed to date is the European Project ELLPAG (European Long-Life Pavement Group). It was founded, in 2002, as a FEHRL group to gather the European knowledge. The group has been active since then, and it has been focused on flexible, semi-rigid and rigid pavements. The advantages of this type of pavements can be very significant, either in terms of economy, serviceability or environment. However, important research needs are still required...

  7. Partner discrepancies in distressed marriages.

    Science.gov (United States)

    Kilmann, Peter Richard; Vendemia, Jennifer M C

    2013-01-01

    Spousal discrepancy theory posits that partners with wide personality differences are at risk for marital distress. In this study, we assessed links between partner personality and interpersonal characteristics and marital distress in 244 couples who sought marital therapy. The sample was divided into three subgroups according to marital duration. Longer-married couples reflected significantly less impulsive, exploitive, and insensitive characteristics than couples in either shorter or intermediate marriages. Couples' marital distress was linked to larger discrepancies in personal distress, impulsivity, interpersonal insensitivity, and self-centered characteristics. While husbands' marital distress was linked to partner differences in personal distress and to impulsive, narcissistic, and competitive characteristics, wives' marital distress was primarily linked to partner discrepancies in self-centeredness. PMID:23484347

  8. Generation mechanisms of tire-pavement noise

    Science.gov (United States)

    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.

  9. Superfícies estriadas no embasamento granítico e vestígio de pavimento de clastos neopaleozóicos na região de Salto, SP / Neopaleozoic striated surfaces in the granitic basement and clast pavement remains of Salto, SP

    Scientific Electronic Library Online (English)

    Annabel, Pérez-Aguilar; Setembrino, Petri; Rafhael, Hypólito; Sibele, Ezaki; Paulo Alves de, Souza; Caetano, Juliani; Lena V.S., Monteiro; Francisco A., Moschini.

    2009-03-01

    Full Text Available Nas proximidades da Cerâmica Guaraú, localizada a sudoeste da cidade de Salto, Estado de São Paulo, dois afloramentos de granito, distantes algumas dezenas de metros um do outro, exibem superfícies estriadas neopaleozóicas. Essas superfícies estão em contato com diamictitos do Subgrupo Itararé. As e [...] strias correspondem a sulcos subparalelos com espaçamento e profundidade milimétrica, possuindo uma direção média de N48°W e mergulhos variando entre 12° e 42° para SE. As feições observadas e a sua associação com diamictitos indicam uma origem por abrasão glacial devido ao movimento de massas de gelo de sudeste para noroeste. A aproximadamente 1,8 km a este da cidade de Salto foi encontrado, no topo de afloramentos de granito, material inconsolidado contendo abundantes clastos de quartzito facetados e estriados. Esses clastos foram interpretados como vestígios de um pavimento de castos. Abstract in english Near Guaraú Ceramic, localized southwest of Salto city in the State of São Paulo, two granite outcrops, distant some tens of meters from each other, display Neopaleozoic striated surfaces. These surfaces are in contact with diamictites from the Itararé Subgroup. The striae correspond to sub parallel [...] grooves with millimetric spacing and depth, oriented about N48E and dipping 12° to 42° towards SE. Observed features and association with diamictites indicate an origin by glacial abrasion due to ice movement from southeast towards northwest. About 1.8 km east of Salto, unconsolidated material containing flat-iron-shaped and striated clasts was found on top of granite outcrops, interpreted as clast pavement remains.

  10. Recycling of water-susceptible pavements

    Science.gov (United States)

    Maupin, G. W.

    1980-05-01

    Several bituminous concrete interstate pavements that experienced failures suspected to have been caused by stripping were investigated. On two projects, the degree of deterioration, potential serviceability, and possible remedial measures were studied. Cores were taken to determine the degreee of stripping and tensile strength, and dynaflect tests were performed. An emulsion mix design was developed for stripped bituminous concrete removed from another project with the expectation that it could be used as a surface mix on a highway with a low traffic volume. While this expectation was not realized, it was concluded that the material is suitable for use in a base mix. A maintenance resurfacing on a fourth project that experienced stripping failure is being monitored and the performance is being evaluated.

  11. Study of the Effect of Temperature Changes on the Elastic Modulus of Flexible Pavement Layers

    Directory of Open Access Journals (Sweden)

    Mohd Raihan Taha

    2013-02-01

    Full Text Available In general, the stiffness of flexible pavement is influenced by environmental changes, whereby temperature and rainfall affect the asphalt layer and non-asphalt layer, such as the subgrade, respectively. Normally, the effect of temperature on flexible pavement can be measured using two methods. The first is a destructive test whereby core samples are tested in a laboratory using a Universal Testing Machine (UTM. The second is a non-destructive in situ test using equipment such as a Falling Weight Deflectometer (FWD and Spectral Analysis of Surface Waves (SASW. This study was conducted to investigate the effect of temperature at different tensile levels on the Soekarno-Hatta and Purwakarta Cikampek roads in Bandung, West Java, Indonesia. It is observed that different tensile levels and testing methods result in various elastic modulus values of flexible pavement. The higher the temperature applied to the flexible pavement layer, the more the elastic modulus values decrease. In contrast, the lower the temperature imposed on the flexible pavement layer, the more the elastic modulus values increase. Different testing methods (FWD, UTM and SASW on the flexible pavement layer are also affected by temperature changes.

  12. Enhancing pavements for thermal applications

    OpenAIRE

    Keikhaei Dehdezi, Pejman

    2012-01-01

    Renewable energy combined with energy efficiency can offer a viable and influential solution to minimise the harmful consequences of both fossil fuel depletion and increases in the cost of power generation. However, in most cases renewable energy technologies require high initial investments that may deter potential users. Pavement Energy Systems (PES) potentially offer a low-cost solution to sustainable and clean energy generation by utilising the thermo-physical properties and design featur...

  13. Moral distress in perinatal nursing.

    Science.gov (United States)

    Tiedje, L B

    2000-09-01

    This work focuses on an emerging concept in nursing ethics--moral distress. Unlike an ethical dilemma where one does not know the right thing to do, in contrast, moral distress occurs when one knows the right thing to do but is constrained by the institution or one's coworkers in doing it. Moral distress is a process that involves recognition that a decision is difficult to act upon; the experience of emotional distress inherent in that situation; choosing strategies; and then acting. Whistle blowing and collaborative practice models both provide strategies for moral action in moral distress situations. Less dramatic and quieter forms of moral action will also be examined. Finally, developing the strength to move from moral distress to moral action will be discussed, as well as research implications for this emerging ethical issue. PMID:11930459

  14. Pervious Pavement System Evaluation-Paper

    Science.gov (United States)

    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...

  15. Pavement Crack Detection Using Spectral Clustering Method

    Directory of Open Access Journals (Sweden)

    Jin Huazhong

    2015-01-01

    Full Text Available Pavement crack detection plays an important role in pavement maintaining and management, nowadays, which could be performed through remote image analysis. Thus, edges of pavement crack should be extracted in advance; in general, traditional edge detection methods don’t consider phase information and the spatial relationship between the adjacent image areas to extract the edges. To overcome the deficiency of the traditional approaches, this paper proposes a pavement crack detection algorithm based on spectral clustering method. Firstly, a measure of similarity between pairs of pixels is taken into account through orientation energy. Then, spatial relationship is needed to find regions where similarity between pixels in a given region is high and similarity between pixels in different regions is low. After that, crack edge detection is completed with spectral clustering method. The presented method has been run on some real life images of pavement crack, experimental results display that the crack detection method of this paper could obtain ideal result.

  16. Volatilization of polycyclic aromatic hydrocarbons from coal-tar-sealed pavement

    Science.gov (United States)

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, are a potential source of volatile PAHs to the atmosphere. An initial assessment of volatilization of PAHs from coal-tar-sealed pavement is presented here in which we measured summertime gas-phase PAH concentrations 0.03 m and 1.28 m above the pavement surface of seven sealed (six with coal-tar-based sealant and one with asphalt-based sealant) and three unsealed (two asphalt and one concrete) parking lots in central Texas. PAHs also were measured in parking lot dust. The geometric mean concentration of the sum of eight frequently detected PAHs (?PAH8) in the 0.03-m samples above sealed lots (1320 ng m-3) during the hottest part of the day was 20 times greater than that above unsealed lots (66.5 ng m-3). The geometric mean concentration in the 1.28-m samples above sealed lots (138 ng m-3) was five times greater than above unsealed lots (26.0 ng m-3). Estimated PAH flux from the sealed lots was 60 times greater than that from unsealed lots (geometric means of 88 and 1.4 ?g m-2 h-1, respectively). Although the data set presented here is small, the much higher estimated fluxes from sealed pavement than from unsealed pavement indicate that coal-tar-based sealants are emitting PAHs to urban air at high rates compared to other paved surfaces.

  17. Modelación del envejecimiento de los pavimentos asfálticos con la metodología de la superficie de respuesta / Pavement Aging Model by Response Surface Modeling

    Scientific Electronic Library Online (English)

    L.E., Chávez-Valencia; C, Hernández-Barriga; A, Manzano-Ramírez.

    2011-12-01

    Full Text Available En la presente investigación se realizó la modelación del envejecimiento de una carpeta asfáltica por medio de la Metodología de Superficie de Respuesta (MSR). Se elaboraron muestras cilíndricas tipo Marshall, que fueron colocadas en un horno bajo las condiciones de tiempo y temperatura establecidos [...] por las condiciones ambientales de la región geográfica donde se construyen pavimentos asfálticos con el AC-20 de la Refinería Ing. Antonio M. Amor, los cuales fueron codificados en la MSR, con esto se determinaron los modelos que predicen el cambio de la estabilidad Marshall (?L) y del flujo (?F), así como la volatilización del material (VM). Además, se extrajeron muestras cilíndricas de una carpeta asfáltica piloto para determinar el error de modelación, observando que el material volatilizado predicho por el modelo VM fue muy cercano al real, no así para los modelos de ?Ly ?F, posiblemente asociado a los factores ambientales que no fueron considerados al inicio de la investigación. Abstract in english In this work, surface course aging was modeled by Response Surface Methodology (RSM). The Marshall specimens were placed in a conventional oven for time and temperature conditions established on the basis of the environment factors of the region where the surface course is constructed by AC-20 from [...] the Ing. Antonio M. Amor refinery. Volatilized material (VM), load resistance increment (?L) and flow resistance increment (?F) models were developed by the RSM. Cylindrical specimens with real aging were extracted from the surface course pilot to evaluate the error of the models. The VM model was adequate, in contrast (?L) and (?F) models were almost adequate with an error of 20 %, that was associated with the other environmental factors, which were not considered at the beginning of the research.

  18. Effective flow resistivity of highway pavements.

    Science.gov (United States)

    Rochat, Judith L; Read, David R

    2013-12-01

    In the case of highway traffic noise, propagating sound is influenced by the ground over which it travels, whether it is the pavement itself or the ground between the highway and nearby communities. Properly accounting for ground type in modeling can increase accuracy in noise impact determinations and noise abatement design. Pavement-specific effective flow resistivity values are being investigated for inclusion in the Federal Highway Administration Traffic Noise Model, which uses these values in the sound propagation algorithms and currently applies a single effective flow resistivity value to all pavement. Pavement-specific effective flow resistivity values were obtained by applying a modified version of the American National Standards Institute S1.18 standard. The data analysis process was tailored to allow for increased sensitivity and extraction of effective flow resistivity values for a broad range of pavements (sound absorptive to reflective). For porous pavements (sound absorptive), it was determined that examination of the measured data can reveal influence from an underlying structure. Use of such techniques can aid in the design of quieter pavements. PMID:25669283

  19. Application of the portable pavement seismic analyser (PSPA) for pavement analysis

    OpenAIRE

    Steyn, Wynand J.vdM.; Sadzik, E.

    2007-01-01

    Paper presented at the 26th Annual Southern African Transport Conference 9 - 12 July 2007 "The challenges of implementing policy?", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT:The Portable Seismic Pavement Analyser (PSPA) is a non-destructive device used for the evaluation of the seismic stiffness of a pavement structure. The device can be used to obtain basic information on the condition of the pavement structure, including parameters such as the seismic stiffness ...

  20. Definition of in situ pavement instrumentation for data collection to develop a pavement performance model

    OpenAIRE

    Salini, Reus; Pais, Jorge C.; Pereira, Paulo A. A.; Santos, Lui?s Picado

    2008-01-01

    After the implementation of the AASHTO Road Test many researches have been carried out regarding material and pavement performance, both in laboratory and in situ. Many methods for pavement evaluation and design were obtained based on empirical or empirical-mechanistic approaches. Nowadays these methods are used in pavement analysis and design supported by a set of shift factors which consider the variables not included in their definition. At the present time, the development of economica...

  1. Assessment of highway pavements using GPR

    Science.gov (United States)

    Plati, Christina; Loizos, Andreas

    2015-04-01

    Highway infrastructure is a prerequisite for a functioning economy and social life. Highways, often prone to congestion and disruption, are one of the aspects of a modern transport network that require maximum efficiency if an integrated transport network, and sustainable mobility, is to be achieved. Assessing the condition of highway structures, to plan subsequent maintenance, is essential to allow the long-term functioning of a road network. Optimizing the methods used for such assessment will lead to better information being obtained about the road and underlying ground conditions. The condition of highway structures will be affected by a number of factors, including the properties of the highway pavement, the supporting sub-base and the subgrade (natural ground), and the ability to obtain good information about the entire road structure, from pavement to subgrade, allows appropriate maintenance programs to be planned. The maintenance of highway pavements causes considerable cost and in many cases obstruction to traffic flow. In this situation, methods that provide information on the present condition of pavement structure non-destructively and economically are of great interest. It has been shown that Ground-Penetrating-Radar (GPR), which is a Non Destructive Technique (NDT), can deliver information that is useful for the planning of pavement maintenance activities. More specifically GPR is used by pavement engineers in order to determine physical properties and characteristics of the pavement structure, information that is valuable for the assessment of pavement condition. This work gives an overview on the practical application of GPR using examples from highway asphalt pavements monitoring. The presented individual applications of GPR pavement diagnostics concern structure homogeneity, thickness of pavement layers, dielectric properties of asphalt materials etc. It is worthwhile mentioning that a number of applications are standard procedures, either separately or in combination with other NDT methods, but even for them there is still a room for improvement and there is still need to set stricter regulations Comparisons between radar results and ground truth data produce evidence in support of the statement that the accuracy and reliability of radar results is sufficient for facing many issues related to the evaluation of asphalt pavements. Thus, benefits and limits of this method are shown and recommendations for GPR inspections are presented. Acknowledgments: This work benefited from networking activities carried out within the EU funded COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar."

  2. Nonlinear Responses of a Two Dimensional Vehicle-pavement System

    Directory of Open Access Journals (Sweden)

    Shaohua Li

    2013-09-01

    Full Text Available The vehicle and pavement are usually investigated separately in vehicle dynamics and pavement dynamics. In this work, a new research scheme is proposed to link the vehicle and pavement model by tire loads and compute the nonlinear dynamic responses by analytical methods. A two-DOF nonlinear vehicle and a Bernoulli-Euler beam on a nonlinear elastic foundation with two simply supported ends compose the nonlinear vehicle-pavement system. The nonlinear tire loads are analytically gained using the averaging method. Then the nonlinear vibration equation of the pavement is obtained using Galerkin method and solved using the multiple scales method. The theoretical solutions are verified by numerical results and the effects of system parameters on pavement vibration are also studied. It is found that the pavement responses excited by tire loads attenuate quickly and small pavement mass, large foundation damping or foundation stiffness may decrease the pavement vibration.

  3. Global warming potential of pavements

    Energy Technology Data Exchange (ETDEWEB)

    Santero, Nicholas J [Department of Civil and Environmental Engineering, 407 McLaughlin Hall, University of California, Berkeley, CA 94720-1712 (United States); Horvath, Arpad, E-mail: njsantero@cal.berkeley.ed, E-mail: horvath@ce.berkeley.ed [Department of Civil and Environmental Engineering, 215B McLaughlin Hall, University of California, Berkeley, CA 94720-1712 (United States)

    2009-09-15

    Pavements comprise an essential and vast infrastructure system supporting our transportation network, yet their impact on the environment is largely unquantified. Previous life-cycle assessments have only included a limited number of the applicable life-cycle components in their analysis. This research expands the current view to include eight different components: materials extraction and production, transportation, onsite equipment, traffic delay, carbonation, lighting, albedo, and rolling resistance. Using global warming potential as the environmental indicator, ranges of potential impact for each component are calculated and compared based on the information uncovered in the existing research. The relative impacts between components are found to be orders of magnitude different in some cases. Context-related factors, such as traffic level and location, are also important elements affecting the impacts of a given component. A strategic method for lowering the global warming potential of a pavement is developed based on the concept that environmental performance is improved most effectively by focusing on components with high impact potentials. This system takes advantage of the fact that small changes in high-impact components will have more effect than large changes in low-impact components.

  4. Global warming potential of pavements

    International Nuclear Information System (INIS)

    Pavements comprise an essential and vast infrastructure system supporting our transportation network, yet their impact on the environment is largely unquantified. Previous life-cycle assessments have only included a limited number of the applicable life-cycle components in their analysis. This research expands the current view to include eight different components: materials extraction and production, transportation, onsite equipment, traffic delay, carbonation, lighting, albedo, and rolling resistance. Using global warming potential as the environmental indicator, ranges of potential impact for each component are calculated and compared based on the information uncovered in the existing research. The relative impacts between components are found to be orders of magnitude different in some cases. Context-related factors, such as traffic level and location, are also important elements affecting the impacts of a given component. A strategic method for lowering the global warming potential of a pavement is developed based on the concept that environmental performance is improved most effectively by focusing on components with high impact potentials. This system takes advantage of the fact that small changes in high-impact components will have more effect than large changes in low-impact components.

  5. Research on tensile strength characteristics of bridge deck pavement bonding layers

    Science.gov (United States)

    Wu, Shaopeng; Han, Jun

    2010-03-01

    As the development of the traffic in the world, the bridge deck pavement is playing a more and more important role in the whole traffic system. Big span bridge has become more and more especially cement concrete bridge, therefore the bridge deck pavement bonding layers are emphasized as an important part of bridge traffic system, which can mitigate travel impact to bridge and magnify stationary or traffic amenity. The quality and durability of deck pavement bonding layer has directly effect on traffic safety, comfort, durability and investment of bridge. It represents the first line of defence against the ingress of water, road de-icing salts and aggressive chemicals. In real project, many early age damage of bridge deck pavement has become serious disease that affecting the function of bridge. During the construction of the bridge deck, many types of asphalt binders were used, such as styrene-butadiene-styrene (SBS) modified asphalt, styrene-butadiene rubber (SBR) modified asphalt, neoprene latex asphalt, etc. In this paper UTM-25 was used to test the tensile strength of different bridge deck pavement bonding layers with the different treatment methods to inter-surface.

  6. Effects on evaporation rates from different water-permeable pavement designs.

    Science.gov (United States)

    Starke, P; Göbel, P; Coldewey, W G

    2011-01-01

    The urban water balance can be attenuated to the natural by water-permeable pavements (WPPs). Furthermore, WPPs have a 16% higher evaporation rate than impermeable pavements, which can lead to a better urban climate. Evaporation rates from pavements are influenced by the pavement surface and by the deeper layers. By a compared evaporation measurement between different WPP designs, the grain size distribution of the sub-base shows no influence on the evaporation rates in a significant way. On the contrary, a sub-base made of a twin-layer decreases the evaporation by 16% compared to a homogeneous sub-base. By a change in the colour of the paving stone, 19% higher evaporation rates could be achieved. A further comparison shows that the transpiration-effect of the grass in grass pavers increases the evaporation rates more than threefold to pervious concrete pavements. These high evapotranspiration rates can not be achieved with a pervious concrete paving stone. In spite of this, the broad field of application of the pervious concrete paving stone increases the importance in regard to the urban climate. PMID:22049757

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

    Science.gov (United States)

    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

  8. Modelling Flexible Pavement Response and Performance

    DEFF Research Database (Denmark)

    Ullidtz, Per

    1998-01-01

    This textbook is primarily concerned with models for predicting the future condition of flexible pavements, as a function of traffic loading, climate, materials, etc., using analytical-empirical methods.

  9. Laboratory assessment of pavement foundation materials

    OpenAIRE

    Cheung, Lam Wah

    1994-01-01

    The main aim of this research was to improve laboratory test methods for describing pavement foundation materials so that analytical design based on appropriate mechanical parameters of materials could be performed in practice. The study started by assessing the relevance of currently available methods to describe materials in pavement foundations and reviewing factors influencing the responses of these materials to repeated loading. Two simplified repeated load triaxial apparatuses of d...

  10. Technical and Economic Sustainability of Concrete Pavements

    OpenAIRE

    Laura Moretti

    2014-01-01

    Economic evaluation of road pavements is as important as their technical and structural design: often only initial construction costs are calculated to assess economic project sustainability. Instead, forgetting maintenance costs exposes society to unacceptable risks of expensive and incorrect decisions. Road pavements design and construction solutions affect maintenance works during service life, which not only entail economical and financial expenditures, but also damage service regularity ...

  11. The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells

    Directory of Open Access Journals (Sweden)

    Halsey Leah E

    2011-02-01

    Full Text Available Abstract Background The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticlinal wall; however, the relationships between these arrays and cell morphogenesis are unclear. Results We developed new quantitative tools to compare population-level growth statistics with time-lapse imaging of cotyledon pavement cells in an intact tissue. The analysis revealed alternating waves of lobe initiation and a phase of lateral isotropic expansion that persisted for days. During lateral isotropic diffuse growth, microtubule organization varied greatly between cell surfaces. Parallel microtubule bundles were distributed unevenly along the anticlinal surface, with subsets marking stable cortical domains at cell indentations and others clearly populating the cortex within convex cell protrusions. Conclusions Pavement cell morphogenesis is discontinuous, and includes punctuated phases of lobe initiation and lateral isotropic expansion. In the epidermis, lateral isotropic growth is independent of pavement cell size and shape. Cortical microtubules along the upper cell surface and stable cortical patches of anticlinal microtubules may coordinate the growth behaviors of orthogonal cell walls. This work illustrates the importance of directly linking protein localization data to the growth behavior of leaf epidermal cells.

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

    Science.gov (United States)

    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

  13. Nondestructive testing of pavements and pavement bases. (a bibliography with abstracts). Report for 1964-Jan 78

    International Nuclear Information System (INIS)

    Nondestructive methods for quality assurance of pavements and pavement bases are investigated in these Government-sponsored research reports. Vibration, nuclear activation, radiometry, and acoustic detection are among the various techniques employed. The updated bibliography contains 114 abstracts, 17 of which are new entries to the previous edition

  14. ARDS (Acute Respiratory Distress Syndrome)

    Science.gov (United States)

    ... on Twitter. What Is ARDS? ARDS, or acute respiratory distress syndrome, is a lung condition that leads ... that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find ...

  15. Back Pain and Emotional Distress

    Science.gov (United States)

    North American Spine Society Public Education Series Back Pain and Emotional Distress Common Reactions to Back Pain Four out of five adults will experience an episode of significant back pain sometime during ...

  16. GPR in Nondestructive Quality Assurance of New Asphalt Pavements

    Science.gov (United States)

    Poikajärvi, J.; Peisa, K.; Narbro, A.

    2012-04-01

    Mara Nord is an international cooperation project financed by Interreg IVA Nord funding program with partners from Finland, Sweden and Norway. One of the objectives in Mara Nord project has been to research the quality assurance of new asphalt pavement. Ground penetrating radar (GPR) survey is used as an alternative method for coring in quality assurance. There exist numerous advantages for the use of GPR. For example, the fluent measuring arrangements without closing the traffic on the road and the extensive continuous profile that can be constructed from the measuring data. Within the framework of Mara Nord Project field tests were organized in Seinäjoki region in Finland on August 2011. The tests were done by four consulting companies from Finland and Rovaniemi University of Applied Sciences. The aim of these tests was to compare the measured dielectric value profiles and the calculated void content profiles of the equipment. The tested equipment was GSSI manufactured SIR-20 and 1 GHz horn antennas. Void content values were calculated using the model presented by Mr. Roimela (1997). All core samples were taken from the right wheel path. The same reference core samples were used when analyzing the data of each GPR equipment. Some samples were taken right after the pavement work was completed with the rest three weeks after during the test measurements. The tests indicated that GPRs have very good repeatability in measuring dielectric changes on top surface layers of asphalt pavements. Furthermore, different GPRs locate the same detectable longitudinal dielectric changes with high accuracy. Some differences were found in the dielectric value levels, yet reproducibility of the calculated void content values was quite good. The test data was also used to evaluate the reliability of the regression model between the dielectric values measured through GPR and the void content of the pavement determined from reference cores. Test data indicated that accurate regression model could not be validated by using test data because of too wide variation. The variation of void content in core sample results was not always registered by GPR with corresponding variation in dielectric value. There was some moisture present in test conditions and this might have influenced the GPR results. There are some reference data from dry conditions which will be used later on for analyzing the influence of moisture. There was also quite wide variation in void content determined from core samples taken close to each other during field tests. However, wide variation was not seen in core samples taken right after the pavement work. It is possible that traffic load had its effect on the asphalt pavement compaction. The results indicate that when using only one survey line it should be located between wheel paths. Another option is GPR void content measurements should be done right after the pavement work.

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

    Science.gov (United States)

    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 ...

  18. Adult respiratory distress syndrome

    International Nuclear Information System (INIS)

    Due to improved emergency resuscitation procedures, and with advancing medical technology in the field of critical care, an increasing number of patients survive the acute phase of shock and catastrophic trauma. Patients who previously died of massive sepsis, hypovolemic or hypotensive shock, multiple fractures, aspiration, toxic inhalation, and massive embolism are now surviving long enough to develop previously unsuspected and unrecognized secondary effects. With increasing frequency, clinicians are recognizing the clinical and radiographic manifestations of pathologic changes in the lungs occurring secondary to various types of massive insult. This paper gives a list of diseases that have been shown to precipitate or predispose to diffuse lung damage. Various terms have been used to describe the lung damage and respiratory failure secondary to these conditions. The term adult respiratory distress syndrome (ARDS) is applied to several cases of sudden respiratory failure in patients with previously healthy lungs following various types of trauma or shock. Numerous investigations and experiments have studied the pathologic changes in ARDS, and, while there is still no clear indication of why it develops, there is now some correlation of the sequential pathologic developments with the clinical and radiographic changes

  19. An Innovative Strategy for Maintenance of Highway Pavement

    OpenAIRE

    Sandeep Choudhary, Dr. P. K. Agarwal

    2013-01-01

    Highway pavement are deteriorating fast due to lack of timely maintenance, leading to higher vehicle operating costs, increasing number of accidents etc. Thus, timely maintenance of the highway pavement is essential. Because, once pavements start to deteriorate; they deteriorate rapidly beyond the point where maintenance is effective. Thus, there is an urgent need to develop a strategy for maintenance of pavement in a huge highway network. In this study, an innovative strategy for maintenance...

  20. Benefits of including hot mix recycled materials in pavement design

    OpenAIRE

    Oliveira, Joel; Pereira, Paulo A. A.; Pais, Jorge C.; Santos, Luís Picado

    2005-01-01

    Pavement recycling is becoming more acceptable among the available techniques for pavement maintenance/rehabilitation. It is based on sustainable development, by reusing materials reclaimed from the pavements and reducing the disposal of asphalt materials. Based on the results obtained from laboratory tests carried out on two bituminous mixtures, one of which including 50% of recycled asphalt, some simulations were made for the design of a pavement where those mixtures would be used as a bitu...

  1. Calculation method for permanent deformation of unbound pavement materials

    OpenAIRE

    Korkiala-Tanttu, Leena

    2009-01-01

    An analytical-mechanistic method for the calculation of permanent deformations of pavements has been developed at the Technical Research Centre of Finland (VTT) over some years by the author. The calculation method is needed in the analytical design procedure of pavements. This research concentrated on the calculation method for permanent deformations in unbound pavement materials. The calculation method was generated based on the results of full-scale accelerated pavement tests along with th...

  2. Effects of traffic loading on portuguese and brazilian pavements performance

    OpenAIRE

    Fernandes Junior, Jose? Leomar; Pais, Jorge C.; Pereira, Paulo A. A.

    2006-01-01

    This work investigated the effects of traffic loading on the performance of Portuguese and Brazilian pavements, aiming to contribute to a better technical regulation of heavy vehicles and cost allocation related to the pavement deterioration. Among the traffic loading factors, this work considered axle load, axle type, tire inflation pressure, and wheel type. Six pavement structures were analyzed where three of them are representative of Portuguese pavements, and three are representative of B...

  3. 47 CFR 80.1109 - Distress, urgency, and safety communications.

    Science.gov (United States)

    2010-10-01

    ...Distress, urgency, and safety communications. 80.1109 Section 80.1109 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) ...Procedures for Distress and Safety Communications § 80.1109 Distress,...

  4. Pavement Design for Curved Road Sections: Fatigue Performance of Interfaces and Longitudinal Top-down Cracking in Multilayered Pavements

    OpenAIRE

    Petit, Christophe; Diakhate?, Malick; Millien, Anne; Phelipot-mardele?, Annabelle; Pouteau, Bertrand

    2009-01-01

    This paper focuses on damage processes other than the main one observed and studied in pavement design. Previous research has targeted the experimental fatigue performance of tack coats. The French Pavement Design method has been chosen herein to illustrate how interface fatigue performance can lead to improved design, especially when pavements are subjected to repeated horizontal loadings. In a curved pavement section, longitudinal top-down cracking is observed, and this damage process may a...

  5. Pavement Sealcoat, PAHs, and the Environment

    Science.gov (United States)

    Van Metre, P. C.; Mahler, B. J.

    2011-12-01

    Recent research by the USGS has identified coal-tar-based pavement sealants as a major source of polycyclic aromatic hydrocarbons (PAHs) to the environment. Coal-tar-based sealcoat is commonly used to coat parking lots and driveways and is typically is 20-35 percent coal tar pitch, a known human carcinogen. Several PAHs are suspected mutagens, carcinogens, and (or) teratogens. In the central and eastern U.S. where the coal-tar-based sealants dominate use, sum-PAH concentration in dust particles from sealcoated pavement is about 1,000 times higher than in the western U.S. where the asphalt-based formulation is prevalent. Source apportionment modeling indicates that particles from sealcoated pavement are contributing the majority of the PAHs to recent lake sediment in 35 U.S. urban lakes and are the primary cause of upward trends in PAHs in many of these lakes. Mobile particles from parking lots with coal-tar-based sealcoat are tracked indoors, resulting in elevated PAH concentrations in house dust. In a recently completed study, volatilization fluxes of PAHs from sealcoated pavement were estimated to be about 60 times fluxes from unsealed pavement. Using a wide variety of methods, the author and colleagues have shown that coal-tar-based sealcoat is a major source of PAHs to the urban environment and might pose risks to aquatic life and human health.

  6. Finite Deformation Analysis of Layered Asphalt Pavement

    Directory of Open Access Journals (Sweden)

    Ming-Jian Li

    2013-01-01

    Full Text Available Layered asphalt pavement structures are usually analyzed applying small deformation theory. In this study, finite deformation theory was employed to achieve more accurate results. The response of pavement structure under vertical and horizontal loads was investigated by three-dimensional finite element method. The calculating results, especially for deflection, on the basis of finite deformation theory are very different from that according to the small deformation theory. And the difference will increase while the stiffness of pavement structure decrease. With only vertical loads, asphalt layer is mainly under compressive stress in three directions. With horizontal loads and vertical loads, shear stress contributes to accumulated plastic deformation in the asphalt layer. Sliding between layers could occur due to the shear stress. Tensile strain can cause fatigue cracking in asphalt layer under low temperature. Due to a small modulus of resilience, there exists a large compressive strain and visible deflection in soil base.

  7. Quantitative analysis of microtubule orientation in interdigitated leaf pavement cells.

    Science.gov (United States)

    Akita, Kae; Higaki, Takumi; Kutsuna, Natsumaro; Hasezawa, Seiichiro

    2015-05-01

    Leaf pavement cells are shaped like a jigsaw puzzle in most dicotyledon species. Molecular genetic studies have identified several genes required for pavement cells morphogenesis and proposed that microtubules play crucial roles in the interdigitation of pavement cells. In this study, we performed quantitative analysis of cortical microtubule orientation in leaf pavement cells in Arabidopsis thaliana. We captured confocal images of cortical microtubules in cotyledon leaf epidermis expressing GFP-tubulin? and quantitatively evaluated the microtubule orientations relative to the pavement cell growth axis using original image processing techniques. Our results showed that microtubules kept parallel orientations to the growth axis during pavement cell growth. In addition, we showed that immersion treatment of seed cotyledons in solutions containing tubulin polymerization and depolymerization inhibitors decreased pavement cell complexity. Treatment with oryzalin and colchicine inhibited the symmetric division of guard mother cells. PMID:26039484

  8. PERCEPTION OF DISTRESS BY OBSESSIVE COMPULSIVE PATIENTS

    OpenAIRE

    Lal, Narottam; Ashok K. Agarwal; Sinha, P. K.

    1986-01-01

    A life event inventory has been used to compare forty obsessive compulsive neurosis patients with equal number of non-psychiatric normal controls which were matched in terms of age, sex and, economic status. Ratings by the obsessionals of the degree of happiness or distress produced by their life experiences revealed that obsessionals have significantly greater mean distress rating i.e., higher mean distress score and significantly more mean numbers of distressing events than non-psychiatric ...

  9. Financial Distress Comparison Across Three Global Regions

    OpenAIRE

    Platt, Harlan D.; Platt, Marjorie B.

    2008-01-01

    Globalization has precipitated movement of output and employment between regions. We examine factors related to corporate financial distress across three continents. Using a multidimensional definition of financial distress we test three hypotheses to explain financial distress using historical financial data. A null hypothesis of a single global model was rejected in favor of a fully relaxed model which created individual financial distress models for each region. This result suggests that d...

  10. Mechanistic - empirical pavement design guide implementation and pavement preservation strategies with asphalt rubber

    OpenAIRE

    Kaloush, Kamil, E.; Way, George B.; Belshe, Mark; Rodezno, Maria Carolina

    2011-01-01

    Asphalt-Rubber (AR) mixtures, with their great fleld performance, have received great attention from many transportation agencies world-wide. Current pavement design procedures do not specifically address the unique engineering properties that these mixtures offer. For example, the Mechanistic-Empirical Pavement Design Guide (MEPDG) did not include asphalt-rubber mixes as part of its calibration and Implementation in the USA. This paper addresses some issues on asphalt rubber mixture...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Application of CalME incremental-recursive method to the evaluation of the structural condition as asphalt pavements

    International Nuclear Information System (INIS)

    CalME procedure represents one of the most advanced tools for the design, of flexible pavements world-wide. IT is an incremental-recursive method, which means that pavements service life must be divided into many time intervals where both structural integrity and environmental conditions can be regarded as constants. It also means that the damage calculated at the end of each interval must be considered as initial condition for the next one. The goal of this type of models is the prediction of the evolution of the different distress mechanisms. The advantages of incremental-recursive procedures versus classical analytical design are shown in this paper. Advantages are shown not only in terms of design, but also as a tool in order to support structural evaluation. In particular, the potential of asphalt fatigue model incorporated in CalME is presented. this model is initially calibrated in the laboratory, and it is then re-calibrated based on the actual performance observed from field deflection testing. The model provides a reliable prediction of the future evolution of the damage of the asphalt mixture. Fatigue model validation has been conducted based on the performance from several flexible sections evaluated in CEDEX full-scale pavements test track. (Author) 14 refs.

  13. A study of tire/pavement interaction noise using near- field acoustical holography

    Science.gov (United States)

    Ruhala, Richard James

    1999-12-01

    In this thesis, Nearfield Acoustical Holography (NAH) is applied as a tool to study the mechanisms of tire/pavement interaction noise-a major contributor to highway noise. NAH is a technique that reconstructs the three-dimensional acoustic field from a two- dimensional measurement of the complex pressure. Since NAH measurements are conducted in the acoustic nearfield, areas of maximum radiation from the tire may be localized with a much finer resolution than with conventional measurements. Not only can acoustic pressure be reconstructed, but also sound intensity vectors and sound power. To extend NAH from controlled, laboratory experiments to harsh realistic conditions of a rolling tire, NAH is modified to incorporate the effects of a moving medium and multiple partially coherent sources. Tire/pavement interaction noise is composed of several sources, e.g. interactions of the leading and trailing edges of the tire with the pavement, and sidewall vibration. Therefore, NAH is modified to improve separation of acoustic fields associated with multiple partially coherent sources. These techniques are used to visualize the acoustic field of a rolling tire on real pavements. A scanning mechanism is attached to an automobile trailer for measurements of tire noise under realistic conditions. Several types of tires are evaluated, including a blank tire, a tire with equally spaced transverse grooves, a tire with only circumferential grooves, and two commercial passenger car tire. The tires are tested on both smooth and rough pavements, and at two speeds (56 km/hr and 80 km/hr). Wavenumber spectra of the tire and pavement surfaces are computed when possible to quantify the roughness levels. Although the measurements were made along a plane 10 cm from the tire sidewall, sound pressure and intensity are reconstructed along a plane touching the surface of the tire to localize noise source. In addition to the side plane, front and rear planes were evaluated for two configurations to enhance the study of leading and trailing edge noise generation. Finally, sound power for each configuration was calculated to evaluate global trends. These results provide further insight into the sources and mechanisms of tire/pavement interaction noise.

  14. Perfectionism, Procrastination, and Psychological Distress

    Science.gov (United States)

    Rice, Kenneth G.; Richardson, Clarissa M. E.; Clark, Dustin

    2012-01-01

    Using a cross-panel design and data from 2 successive cohorts of college students ( N = 357), we examined the stability of maladaptive perfectionism, procrastination, and psychological distress across 3 time points within a college semester. Each construct was substantially stable over time, with procrastination being especially stable. We also…

  15. Over the Edge and Back: What to Do If You Drive Off the Pavement Edge

    Science.gov (United States)

    ... crashes on similar roads. AAA Foundationfor Traffic Safety Pavement edge drop-off “ Pavement edge drop-off crashes are over twice as ... What to do if you drive off the pavement edge • • IF THERE ARE NO OBSTACLES DIRECTLY IN ...

  16. Permeable pavement research ? Edison, New Jersey

    Science.gov (United States)

    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...

  17. Pavement Sealcoat, PAHs, and Water Quality of Urban Water Bodies: An Overview

    Science.gov (United States)

    Mahler, B. J.; Van Metre, P. C.; Ingersoll, C.; Kunz, J. L.; Kienzler, A.; Devaux, A.; Bony, S.

    2014-12-01

    Coal-tar-based (CT) sealcoat is used to protect and beautify the asphalt pavement of driveways and parking lots primarily in the central, southern, and northeastern U.S. and in Canada. CT sealcoat typically is 20 to 35 percent crude coal tar or coal-tar pitch and contains from 50,000 to 100,000 mg/kg PAHs, about 1,000 times more than asphalt-based (AS) sealcoat or asphalt itself. Tires and snowplows abrade the friable sealcoat surface into fine particles—PAH concentrations in fine particles (dust) from CT-sealcoated pavement are about 1,000 times higher than in dust from AS-sealcoated pavement (median total PAH concentrations 2,200 and 2.1 mg/kg, respectively). Use of CT sealcoat has several implications for urban streams and lakes. Source apportionment modeling has indicated that, in regions where CT sealcoat is prevalent, particles from sealcoated pavement are contributing the majority of the PAHs to recently deposited lake sediment, with implications for ecological health. Acute 2-d toxicity of runoff from CT-sealcoated pavement to stream biota, demonstrated for a cladoceran (Ceriodaphnia dubia) and fathead minnows (Pimephales promelas), continues for samples collected as long as weeks or months following sealcoat application. Using the fish-liver cell line RGL-W1, runoff collected as much as 36 days following CT-sealcoat application has been demonstrated to cause DNA damage and impair DNA repair capacity. These results demonstrate that CT runoff is a potential hazard to aquatic ecosystems for at least several weeks after sealant application, and that exposure to sunlight can enhance toxicity and genetic damage. Recent research has provided direct evidence that restricting use of CT sealcoat in a watershed can lead to a substantial reduction in PAH concentrations in receiving water bodies.

  18. Analysis of Asphalt Pavement under Nonuniform Tire-pavement Contact Stress using Finite Element Method

    Directory of Open Access Journals (Sweden)

    A.K. Ariffin

    2011-01-01

    Full Text Available Tire-pavement contact stress is traditionally assumed to be uniformly distributed over a circular contact area. In this study, the tire-pavement contact pressure has been modeled to be nonuniform. A new tire model is developed for the analysis based on the geometry of the tire footprint because the contact area between the tire and the pavement is not exactly rectangular or circular. The objective of this study is to develop a finite element model based on viscoplastic theory for simulating the laboratory testing of asphalt mixes in Hamburg Wheel Rut Tester (HWRT for rutting and to model in-situ pavement performance. The creep parameters C1, C2 and C2 are developed from the triaxial repeated load creep test at 50C and at frequency of 1 Hz. Viscoplastic model (creep model is adopted and a commercially available Finite Element (FE program, ANSYS, is used in this study, in order to predict the rutting for in-situ pavement under nonuniform contact pressure. In the simulation, the used element has an eight-node with a three degrees of freedom per node translations in the nodal x, y and z directions. Dual wheel system of a standard axle load of 80 kN is used in the 2D pavement in-situ performance analysis. Reasonable agreement has been obtained between the predicted rut depths and the measured one. Moreover, it is found that creep model parameter C1, strongly influences rutting than the parameter C3. Finally it can be concluded that creep model based on finite element method can be used as an effective tools to analyze rutting of asphalt pavements.

  19. Global Cooling: Policies to Cool the World and Offset Global Warming from CO2 Using Reflective Roofs and Pavements

    Energy Technology Data Exchange (ETDEWEB)

    Akbari, Hashem; Levinson, Ronnen; Rosenfeld, Arthur; Elliot, Matthew

    2009-08-28

    Increasing the solar reflectance of the urban surface reduce its solar heat gain, lowers its temperatures, and decreases its outflow of thermal infrared radiation into the atmosphere. This process of 'negative radiative forcing' can help counter the effects of global warming. In addition, cool roofs reduce cooling-energy use in air conditioned buildings and increase comfort in unconditioned buildings; and cool roofs and cool pavements mitigate summer urban heat islands, improving outdoor air quality and comfort. Installing cool roofs and cool pavements in cities worldwide is a compelling win-win-win activity that can be undertaken immediately, outside of international negotiations to cap CO{sub 2} emissions. We propose an international campaign to use solar reflective materials when roofs and pavements are built or resurfaced in temperate and tropical regions.

  20. INVESTIGATION OF SKID RESISTANCE PROPERTIES OF AGGREGATES USED IN AFYONKARAHISAR CITY PAVEMENTS

    Directory of Open Access Journals (Sweden)

    Cahit GÜRER

    2007-02-01

    Full Text Available For a safe driving, pavement surface aggregates must have superior physical and mechanical properties. Although high rate of accidents is mainly due to drivers errors, pavement surface properties affect significantly occurance of traffic accidents. The most important factor in the highways leading to traffic accidents are the skid resistance. In this study, adherence test with Vialit plate, Nicholson stripping test, accelerated polishing test (PSV were carried out on four aggregate samples which were used in seal coats and hot mix asphalt in Afyonkarahisar City. Results were compared with values of specification limits. The results showed that particularly limestone aggregates polishing stone values are poorer than volcanic aggregates sample. Especially, use of aggregates having a good polishing resistance, will be an important factor increasing driving safety.

  1. Evaluating Pavement Cracks with Bidimensional Empirical Mode Decomposition

    OpenAIRE

    Nii Attoh-Okine; Albert Ayenu-Prah

    2008-01-01

    Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD), a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decomposition (EMD), which can decompose nonlinear and nonstationary signals into basis functions called ...

  2. Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete

    OpenAIRE

    Fidelis O. OKAFOR

    2010-01-01

    Recycled asphalt pavement (RAP) is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely...

  3. Pervious Concrete: New Era For Rural Road Pavement

    OpenAIRE

    Darshan S Shah, Prof Jayeshkumar Pitroda Prof J. J. Bhavsar

    2013-01-01

    Pervious concrete is a relatively new concept for rural road pavement, with increase into the problems in rural areas related to the low ground water level, agricultural problem. Pervious concrete has introduced in rural road as a road pavement material. Pervious concrete as a paving material has seen renewed interest due to its ability to allow waterto flow through itself to recharge groundwater level and minimize storm water runoff. This introduction topervious concrete pavements reviews it...

  4. Evaluation of Road Pavement Density Using Ground Penetrating Radar

    OpenAIRE

    Rsa, Raja Abdullah; Shafri, H. Zulhaidi M.; Mardeni, R.; Sabira Khatun; Muniandy, R.

    2009-01-01

    This study describes an analysis of Ground Penetrating Radar (GPR) measurements at frequency range of 1.7-2.6 GHz to get a relationship between attenuation and density for nine road pavements slabs with different densities. There are about four different frequencies had been tested. The method is simple, fast, non-destructive and accurate way to determine the density of road pavement. Density is a one of the important parameter in order to determine the compressive strength of road pavement f...

  5. Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements

    OpenAIRE

    Tarefder R.; Ahmed M.U.; Rahman M.M.

    2013-01-01

    This study evaluates airfield pavements’ functional- and structural-condition to determine the most economical maintenance method. As a part of the analysis, Pavement Condition Index (PCI) for several runways, taxiways, and aprons has been determined by MicroPAVER. Structural evaluation of airport pavements has been performed by Falling Weight Deflectometer (FWD) test. Evaluation of Layer Moduli and Overlay Design (ELMOD) also determines the required overlay thickness based on the E-values,...

  6. Artificial Neural Network Application for Flexible Pavement Thickness Modeling

    OpenAIRE

    Saltan, Mehmet; Tig?demi?r, Mesut; Karas?ahi?n, Mustafa

    2002-01-01

    Flexible pavements are affected by moving vehicles, climate and other environmental factors. As a result of these factors, the pavement starts to deteriorate. In order to prevent further deterioration, a maintenance program should be carried out at right time and right places. For the determination of the structural carrying capacity of the pavement, non-destructive testing equipments are used. These are mainly Benkelman Beam, dynaflect, road rater and falling weight deflectometer (FWD). In...

  7. Unconventional Banking System in Distress

    OpenAIRE

    Wassim Rajhi; Slim Ahmed Hassairi

    2011-01-01

    AbstractWith the proliferation of banking sector problems around the world, in the last few years the empirical literature on systemic banking crises has grown significantly. This literature has frequently focused attention on the factors connected with the onset of conventional banking distress, in order to identify the determinants of the crises or to look for “early warning indicators” of difficulty. In fact a number of studies have relied on factors determining bank failures related t...

  8. Stabilization of Black Cotton Soil With Sand and Cement as a Subgrade for Pavement

    OpenAIRE

    Mrs. Neetu B. Ramteke *1 ,; Prof. Anilkumar Saxena 2 ,; , Prof. T. R. Arora 3

    2014-01-01

    Expansive soil (Black cotton soil) is very weak and does not have enough stability for any type of construction work. In pavement, subgrade layer is the bottommost layer underlying the base course or surface course. To make the subgrade soil stable, by improving its engineering properties is very essential. In the present work, stabilization of subgrade soil by using sand and cement (varying percentage of sand and constant percentage of cement by weight of soil) is used to enh...

  9. Incidence of respiratory distress syndrome

    International Nuclear Information System (INIS)

    Objective: To determine the incidence of respiratory distress syndrome (RDS) in hospital born babies. Subjects and Methods: All live born infants delivered at the hospital and who fulfilled the diagnostic criteria of respiratory distress syndrome (RDS) were included in the study. Results: Ninety-four neonates developed RDS. Out of these, 88 (93.61%) were preterm and 06 (6.38%) were term infants. There was a male preponderance (65.95%). RDS was documented in 1.72% of total live births. 37.28% of preterm and 0.11% of term neonates born at the hospital. The incidence of RDS was 100% at 26 or less weeks of gestation, 57.14% at 32 weeks, and 3.70% at 36 weeks. The mortality with RDS was 41 (43.61%). Conclusion: RDS is the commonest cause of respiratory distress in the newborn, particularly, in preterm infants. It carries a high mortality rate and the incidence is more than that documented in the Western world. (author)

  10. Unconventional Banking System in Distress

    Directory of Open Access Journals (Sweden)

    Wassim Rajhi

    2011-08-01

    Full Text Available AbstractWith the proliferation of banking sector problems around the world, in the last few years the empirical literature on systemic banking crises has grown significantly. This literature has frequently focused attention on the factors connected with the onset of conventional banking distress, in order to identify the determinants of the crises or to look for “early warning indicators” of difficulty. In fact a number of studies have relied on factors determining bank failures related to conventional rather than Islamic information. A lack of study and comprehension therefore has been a major challenge. Regrettably Islamic banking still remains enigmatic. The central aim of this paper is to elucidate the sense of Islamic banking distress and expose collapse. This study contributes to this ongoing debate over the Banking Distress of Islamic bank with the following distinct features. First, we pay attention to size and the factors determining bank failures for the unconventional. Second, we try to identify some cases of banks facing these problems. As mentioned below banks face difficulties in the present-day environment, and Islamic banks are no exception. Given all these constraints, it would be necessary to adopt measures to ovoid collapse which will be treated in the last part.

  11. Desempeño de pavimentos estabilizado con asfalto espumado en una prueba de pavimentos a escala real y carga acelerada Performance of foamed bitumen pavements in accelerated testing facility

    Directory of Open Access Journals (Sweden)

    Alvaro Gonzalez

    2012-08-01

    Full Text Available Uno de los objetivos claves de la gestión de pavimentos es desarrollar e implementar una estrategia de construcción y mantenimiento rentables, con el fin de alcanzar niveles requeridos de servicio y desempeño. Una técnica rentable y sustentable para la rehabilitación de pavimentos es la de estabilización o reciclado con asfalto espumado (AE. Este artículo presenta un estudio sobre el desempeño de pavimentos estabilizados con asfalto espumado en el Canterbury Accelerated Pavement Testing Indoor Facility CAPTIF. CAPTIF es un laboratorio a escala real para pavimentos ubicado en Nueva Zelandia, que permite aplicar un gran número de cargas de tráfico en un breve período de tiempo. Seis secciones de pavimentos con distintos contenidos de asfalto y cemento fueron ensayadas en CAPTIF. Los resultados del experimento mostraron que las deflexiones disminuyen en las secciones con mayor contenido de asfalto espumado. Luego de aplicar más de un millón de ciclos de carga, las secciones estabilizadas sólo con cemento, sólo con asfalto y la sección sin estabilizar mostraron un deterioro significativo en forma de ahuellamiento. Por otro lado, las secciones que fueron estabilizadas con AE y cemento mostraron un buen desempeño, demostrando que el cemento y el AE juntos mejoran significativamente el desempeño del pavimento. Los resultados de ahuellamiento fueron empleados para desarrollar modelos y describir el deterioro estable y acelerado de los pavimentos en estudio, lo que puede ser utilizado para una mejor gestión de los pavimentos estabilizados con asfalto espumado.One of the key principal goals of pavement asset management is to develop and implement cost-effective pavement construction and maintenance strategies that achieve the required levels of service and performance. A sustainable, cost-effective technique for rehabilitating pavements is foamed bitumen stabilization. This paper presents a study on the performance of foamed bitumen pavements tested in the Canterbury Accelerated Pavement Testing indoor Facility (CAPTiF, for full scale testing of pavements. Six pavement sections were tested; the variables were bitumen and cement content; one control section with the untreated unbound material was tested. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs, the sections stabilised with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilised with foamed bitumen and 1.0% cement, showing that cement and FB together significantly improve pavement performance. The rutting results were used to develop models to describe the stable and unstable performance of the tested pavements. The paper concludes by outlining some of the practical benefits of utilising this technology in pavement asset management.

  12. Desempeño de pavimentos estabilizado con asfalto espumado en una prueba de pavimentos a escala real y carga acelerada / Performance of foamed bitumen pavements in accelerated testing facility

    Scientific Electronic Library Online (English)

    Alvaro, Gonzalez; Misko, Cubrinovski; Bryan, Pidwerbesky; David, Alabaster.

    2012-08-01

    Full Text Available Uno de los objetivos claves de la gestión de pavimentos es desarrollar e implementar una estrategia de construcción y mantenimiento rentables, con el fin de alcanzar niveles requeridos de servicio y desempeño. Una técnica rentable y sustentable para la rehabilitación de pavimentos es la de estabiliz [...] ación o reciclado con asfalto espumado (AE). Este artículo presenta un estudio sobre el desempeño de pavimentos estabilizados con asfalto espumado en el Canterbury Accelerated Pavement Testing Indoor Facility CAPTIF. CAPTIF es un laboratorio a escala real para pavimentos ubicado en Nueva Zelandia, que permite aplicar un gran número de cargas de tráfico en un breve período de tiempo. Seis secciones de pavimentos con distintos contenidos de asfalto y cemento fueron ensayadas en CAPTIF. Los resultados del experimento mostraron que las deflexiones disminuyen en las secciones con mayor contenido de asfalto espumado. Luego de aplicar más de un millón de ciclos de carga, las secciones estabilizadas sólo con cemento, sólo con asfalto y la sección sin estabilizar mostraron un deterioro significativo en forma de ahuellamiento. Por otro lado, las secciones que fueron estabilizadas con AE y cemento mostraron un buen desempeño, demostrando que el cemento y el AE juntos mejoran significativamente el desempeño del pavimento. Los resultados de ahuellamiento fueron empleados para desarrollar modelos y describir el deterioro estable y acelerado de los pavimentos en estudio, lo que puede ser utilizado para una mejor gestión de los pavimentos estabilizados con asfalto espumado. Abstract in english One of the key principal goals of pavement asset management is to develop and implement cost-effective pavement construction and maintenance strategies that achieve the required levels of service and performance. A sustainable, cost-effective technique for rehabilitating pavements is foamed bitumen [...] stabilization. This paper presents a study on the performance of foamed bitumen pavements tested in the Canterbury Accelerated Pavement Testing indoor Facility (CAPTiF), for full scale testing of pavements. Six pavement sections were tested; the variables were bitumen and cement content; one control section with the untreated unbound material was tested. Results showed that surface deflections decreased at sections with higher bitumen contents. After the application of 5,710,000 Equivalent Standard Axles (ESAs), the sections stabilised with cement only, bitumen only, and the control section all showed large amounts of rutting. Conversely, little rutting was observed in the three sections stabilised with foamed bitumen and 1.0% cement, showing that cement and FB together significantly improve pavement performance. The rutting results were used to develop models to describe the stable and unstable performance of the tested pavements. The paper concludes by outlining some of the practical benefits of utilising this technology in pavement asset management.

  13. Smart Road Pavement Research HomePage

    Science.gov (United States)

    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.

  14. Measurements of the stiffness and thickness of the pavement asphalt layer using the enhanced resonance search method.

    Science.gov (United States)

    Zakaria, Nur Mustakiza; Yusoff, Nur Izzi Md; Hardwiyono, Sentot; Nayan, Khairul Anuar Mohd; El-Shafie, Ahmed

    2014-01-01

    Enhanced resonance search (ERS) is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner). This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard. PMID:25276854

  15. Ultra thin reinforced concrete pavement: practical applications

    OpenAIRE

    Brink, J. H.

    2012-01-01

    Over the last decade considerable research effort has led to the development of Ultra Thin Reinforced Concrete Pavements (UTRCP). The objective of this paper is to present practical refinements to the original concepts and theories. This paper will briefly discuss the development of UTRCP, and problems encountered during the implementation of UTRCP technology. Refinements were proposed and implemented in a number of projects. These projects are discussed and illustrated to demonstrate the use...

  16. Designing of asphalt pavements on parking lots

    OpenAIRE

    Bratina, Laura

    2013-01-01

    A parking lot is the first part of a building complex to be viewed by the user. It is important that those areas are properly designed to provide the designed service life expectency, low maintainance costs and aestetic pavement. In Slovenia, specifications for designing the parking lots do not exist. There exists Tehnical specifications which are used on classified roads exposed to dynamic loadings. There are several analitical, empirical and standardised procedures in designing paveme...

  17. A "wreckers theory" of financial distress

    OpenAIRE

    von Kalckreuth, Ulf

    2005-01-01

    In recent years, a number of papers have established a new empirical regularity. Stocks of distressed firms vastly underperform those of financially healthy firms. It is not necessary to attribute the negative excess returns of distressed firms to inefficient or irrational markets. We show that negative excess returns are the equilibrium outcome when a subset of participants is able to draw returns "in kind" from distressed companies. For firms close to bankruptcy, non-cash returns to ownersh...

  18. Financial Distress Comparison Across Three Global Regions

    Directory of Open Access Journals (Sweden)

    Harlan D. Platt

    2008-12-01

    Full Text Available Globalization has precipitated movement of output and employment between regions. We examine factors related to corporate financial distress across three continents. Using a multidimensional definition of financial distress we test three hypotheses to explain financial distress using historical financial data. A null hypothesis of a single global model was rejected in favor of a fully relaxed model which created individual financial distress models for each region. This result suggests that despite other indications of worldwide convergence, international differences in accounting rules, lending practices, managements skill levels, and legal requirements among others has kept corporate decline from becoming commoditized.

  19. Work flow of signal processing data of ground penetrating radar case of rigid pavement measurements

    Science.gov (United States)

    Handayani, Gunawan

    2015-04-01

    The signal processing of Ground Penetrating Radar (GPR) requires a certain work flow to obtain good results. Even though the Ground Penetrating Radar data looks similar with seismic reflection data, but the GPR data has particular signatures that the seismic reflection data does not have. This is something to do with coupling between antennae and the ground surface. Because of this, the GPR data should be treated differently from the seismic signal data processing work flow. Even though most of the processing steps still follow the same work flow of seismic reflection data such as: filtering, predictive deconvolution etc. This paper presents the work flow of GPR processing data on rigid pavement measurements. The processing steps start from raw data, de-Wow process, remove DC and continue with the standard process to get rid of noises i.e. filtering process. Some radargram particular features of rigid pavement along with pile foundations are presented.

  20. Characterization of nanoparticles released during construction of photocatalytic pavements using engineered nanoparticles

    International Nuclear Information System (INIS)

    With the increasing use of titanium dioxide (TiO2) nanoparticles in self-cleaning materials such as photocatalytic concrete pavements, the release of nanoparticles into the environment is inevitable. Nanoparticle concentration, particle size, surface area, elemental composition, and surface morphology are pertinent to determine the associated risks. In this study, the potential of exposure to synthetic nanoparticles released during construction activities for application of photocatalytic pavements was measured during laboratory-simulated construction activities of photocatalytic mortar overlays and in an actual field application of photocatalytic spray coat. A scanning mobility particle sizer system measured the size distribution of nanoparticles released during laboratory and field activities. Since incidental nanoparticles are released during construction activities, nanoparticle emissions were compared to those from similar activities without nano-TiO2. Nanoparticle counts and size distribution suggest that synthetic nanoparticles are released during application of photocatalytic pavements. In order to identify the nanoparticle source, nanoparticles were also collected for offline characterization using transmission electron microscopy. However, positive identification of synthetic nanoparticles was not possible due to difficulties in obtaining high-resolution images. As a result, further research is recommended to identify nanoparticle comporecommended to identify nanoparticle composition and sources.

  1. The acute respiratory distress syndrome.

    Science.gov (United States)

    Modrykamien, Ariel M; Gupta, Pooja

    2015-04-01

    The acute respiratory distress syndrome (ARDS) is a major cause of acute respiratory failure. Its development leads to high rates of mortality, as well as short- and long-term complications, such as physical and cognitive impairment. Therefore, early recognition of this syndrome and application of demonstrated therapeutic interventions are essential to change the natural course of this devastating entity. In this review article, we describe updated concepts in ARDS. Specifically, we discuss the new definition of ARDS, its risk factors and pathophysiology, and current evidence regarding ventilation management, adjunctive therapies, and intervention required in refractory hypoxemia. PMID:25829644

  2. Permeable pavement demonstration at the Edison Environmental Center

    Science.gov (United States)

    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...

  3. Permeable Pavement Research at the Edison Environmental Center

    Science.gov (United States)

    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...

  4. Modeling the Hydrologic Processes of a Permeable Pavement System

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

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

    Science.gov (United States)

    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...

  7. Full-Depth Asphalt Pavements for Parking Lots and Driveways.

    Science.gov (United States)

    Asphalt Inst., College Park, MD.

    The latest information for designing full-depth asphalt pavements for parking lots and driveways is covered in relationship to the continued increase in vehicle registration. It is based on The Asphalt Institute's Thickness Design Manual, Series No. 1 (MS-1), Seventh Edition, which covers all aspects of asphalt pavement thickness design in detail,…

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

    Science.gov (United States)

    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. Comparative Study of French and Chinese Asphalt Pavement Design Methods

    Directory of Open Access Journals (Sweden)

    Pierre Guy Atangana Njock

    2015-01-01

    Full Text Available This study deals with the comparison of French and Chinese approaches for the design of flexible pavement. The Finite Element Analysis (FEA using ANSYS was used to compute and compare the mechanical responses in four typical pavement structures used in France and China, for respective axle type and loads. The study concluded that the maximum deflection in typical structure of stabilized asphalt pavement in China is greater than that obtained in the typical treated bases asphalt pavement in France. Therefore, the high modulus materials used in the French method allows the structure to have a high rutting resistance compared to Chinese pavement structures whose the values of the elastic modulus of materials are relatively lower. The results also shown that, the Chinese methodology is advantageous for the design of semi-rigid asphalt pavement, in terms of the mechanical response at the bottom of treated base layer. There are considerable differences between the equivalent axle load conversion methods and the reference axles loads used in France and in China and both methodologies pavement design indexes are established on the criterion of fatigue at the bottom of asphaltic concrete layer for acceptable pavement performance at the end of the design period (i.e., acceptable levels of rutting, fatigue cracking and thermal cracking.

  10. Evaluation of a highway pavement using non destructive tests: Falling Weight Deflectometer and Ground Penetrating Radar

    Science.gov (United States)

    Marecos, Vania; Fontul, Simona; de Lurdes Antunes, Maria

    2015-04-01

    This paper presents the results of the application of Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) to assess the bearing capacity of a rehabilitated flexible highway pavement that began to show the occurrence of cracks in the surface layer, about one year after the improvement works. A visual inspection of the surface of the pavement was performed to identify and characterize the cracks. Several core drills were done to analyse the cracks propagation in depth, these cores were also used for GPR data calibration. From the visual inspection it was concluded that the development of the cracks were top-down and that the cracks were located predominantly in the wheel paths. To determine the thickness of the bituminous and granular layers GPR tests were carried out using two horn antennas of 1,0 GHz and 1,8 GHz and a radar control unit SIR-20, both from GSSI. FWD load tests were performed on the wheel paths and structural models were established, based on the deflections measured, through back calculation. The deformation modulus of the layers was calculated and the bearing capacity of the pavement was determined. Summing up, within this study the GPR was used to continuously detect the layer thickness and the GPR survey data was calibrated with core drills. The results showed variations in the bituminous layer thickness in comparison to project data. From the load tests it was concluded that the deformation modulus of the bituminous layers were also vary variable. Limitations on the pavement bearing capacity were detected in the areas with the lower deformation modulus. This abstract is of interest for COST Action TU1208 Civil Engineering Applications of Ground Penetrating Radar.

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

    Science.gov (United States)

    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 (2-6 mm 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 (10-15 mm) 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

  12. 46 CFR 169.553 - Pyrotechnic distress signals.

    Science.gov (United States)

    2010-10-01

    ...2010-10-01 2010-10-01 false Pyrotechnic distress signals. 169.553 Section...Additional Lifesaving Equipment § 169.553 Pyrotechnic distress signals. (a) All pyrotechnic distress signals must be of an...

  13. Pervious Concrete: New Era For Rural Road Pavement

    Directory of Open Access Journals (Sweden)

    Darshan S. Shah 1 , Prof. Jayeshkumar Pitroda2Prof.J.J.Bhavsar

    2013-08-01

    Full Text Available Pervious concrete is a relatively new concept for rural road pavement, with increase into the problems in rural areas related to the low ground water level, agricultural problem. Pervious concrete has introduced in rural road as a road pavement material. Pervious concrete as a paving material has seen renewed interest due to its ability to allow waterto flow through itself to recharge groundwater level and minimize storm water runoff. This introduction topervious concrete pavements reviews its applications and engineering properties, including environmentalbenefits, structural properties, and durability.In rural area cost consideration is the primary factor which must be kept in mind. So that in rural areas costly storm water management practices is not applicable. Pervious concrete pavement is unique and effective means to meet growing environmental demands. By capturing rainwater and allowing it to seep into the ground. This pavement technology createsmore efficient land use by eliminating the need for retention ponds, swell, and other costly stormwater management devices.

  14. Rehabilitation of heavy duty concrete pavements prediction of foamed bitumen mixtures

    OpenAIRE

    Du Plessis, B. M.; Visser, Alex T.

    2001-01-01

    In container ports pavements are subjected to ultra heavy wheel loads that may greatly exceed those of highway trucks, but often fewer repetitions are applied. These pavements are typically termed heavy duty pavements. The heavy duty pavement at the Transnet Container holding area at City Deep, Johannesburg had been in service for about 20 years and it showed severe cracking. The pavement was still serviceable and in operation, but rehabilitation or rebuilding had to be done in order to preve...

  15. Full scale tests on grid reinforced flexible pavements on the French fatigue carrousel

    OpenAIRE

    Hornych, Pierre; Kerzreho, Jean Pierre; Chabot, Armelle; Trichet, Ste?phane; Sohm, Juliette; Joutang, Jean-luc; Bastard, Nicolas

    2012-01-01

    Grids are increasingly used. They have proved their efficiency, but there is presently no widely accepted design method to predict the long term life of grid reinforced pavements. This paper describes a full scale experiment carried out on the large pavement fatigue carrousel of IFSTTAR, to test simultaneously 3 pavement sections with different types of grids, in comparison with an unreinforced pavement structure. The tests are carried out on typical French low traffic pavement structures. Re...

  16. Permeable Pavement Research ? Edison, NJ

    Science.gov (United States)

    This presentation gives the rationale behind NRMRL?s decision to construct and test a permeable surface parking lot the Edison Environmental Center. It also describes the monitoring program and gives preliminary results. The presentation is being given at the request of the New...

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

    Science.gov (United States)

    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.

  18. Depletion of E. coli in permeable pavement mineral aggregate storage and reuse systems.

    Science.gov (United States)

    Myers, B R; Beecham, S; van Leeuwen, J A; Keegan, A

    2009-01-01

    Permeable pavement reservoirs provide an important opportunity for the harvesting and storage of stormwater for reuse. This research aims to determine whether storage in dolomite, calcite and quartzite mineral aggregates in the base course of a permeable pavement impacts on the survival of the pathogen indicator organism Escherichia coli (E. coli) in storage. The reasons for depletion were also investigated. Twelve model permeable pavement storage reservoirs were filled, in triplicate, with dolomite, calcite and quartzite. Three reservoirs contained no aggregate. After filling with pathogen spiked rainwater, the concentration of E. coli was examined for 22 days in the reservoirs. The reservoirs were then agitated to determine if there was E. coli present which was not in aqueous suspension. The results of the experiments show that there is no significant difference in the depletion of E. coli found in reservoirs without aggregate, and those filled with dolomite or calcite. The rate of depletion was found to be significantly lower in the quartzite filled reservoirs. Agitation of the reservoirs yielded increases in the aqueous concentration of E. coli in all reservoir types, suggesting that the bacteria are adhering to the surface of the mineral aggregate and to the reservoir walls. PMID:19955632

  19. An Innovative Strategy for Maintenance of Highway Pavement

    Directory of Open Access Journals (Sweden)

    Sandeep Choudhary, Dr. P. K. Agarwal

    2013-05-01

    Full Text Available Highway pavement are deteriorating fast due to lack of timely maintenance, leading to higher vehicle operating costs, increasing number of accidents etc. Thus, timely maintenance of the highway pavement is essential. Because, once pavements start to deteriorate; they deteriorate rapidly beyond the point where maintenance is effective. Thus, there is an urgent need to develop a strategy for maintenance of pavement in a huge highway network. In this study, an innovative strategy for maintenance of highway pavement is proposed. A two stage maintenance strategy is proposed. In stage I, it is proposed to determine priority of highway sections. In Stage II, priority of various maintenance activities to be carried out on various sections will be determined. Maintenance priority of the pavement is based on importance of the road sections, present road conditions, and future road conditions. The methodology proposed in this study is illustrated with the help of example of some hypothetical highway network consisting of 4 sections. Analysis results indicated that the proposed strategy is considered to be more rational, innovative & logical. Some strategies for maintenance of urban roads are also presented in this study. Therefore, it is expected that this study will be useful for maintenance of huge highway network in India and thus will be useful for preserving huge asset of pavement infrastructure.

  20. Liquidity Risk and Distressed Equity

    DEFF Research Database (Denmark)

    Medhat, Mamdouh

    I show theoretically and empirically that cash holdings can help rationalize the low returns to distressed equity. In my model, levered firms with financing constraints optimally choose their cash holdings to eliminate liquidity risk and optimally default when insolvent. Using data on solvency, liquidity, and returns for US firms, I find evidence consistent with the model’s predictions: (1) In all solvency levels, the average firm holds enough liquid assets to cover its short-term liabilities; less solvent firms have (2) a higher fraction of their total assets in liquid assets and therefore (3) lower conditional betas and (4) lower returns; (5) the profits of long-short solvency strategies are highest among firms with low liquidity; and (6) the profits of long-short liquidity strategies are highest among firms with low solvency.

  1. Time series observations of marsh recovery and pavement persistence at three Metula spill sites after 30.5 years

    International Nuclear Information System (INIS)

    In 1974, the oil tanker Metula ran aground in the Strait of Magellan, Chile and spilled about 50,000 tons of light Arabian crude and 2,000 tons of Bunker C fuel. No attempt was made to recover or treat the stranded oil and the coast was left to recover by natural attenuation. Field visits to the coastal sites affected by the spill were conducted 30 years after the incident. The survey in 2005 repeated observations and measurements made in 1998 in the heavily affected Punta Espora area that documented salt marsh recovery at 2 sites, and changes in asphalt pavement at a third site. The 1998 survey also indicated that tilling was responsible for a significant increase in the number of plants that recolonized the area. A comparison of the plant counts between 1998 and 2005 showed that the number of plants in tilled plots was reduced because of fewer larger plants. A comparison of oil distribution in the west marsh from 1998 to 2005 showed that recolonization was evident. A large 550 m-long asphalt pavement on a mixed sediment beach showed very little changes in pavement area in the aftermath of the spill. However, the upper edge of the pavement showed signs of erosion by backwash action of waves during high-tide. The presence of surface oil cover continues to dominate the physical character of the upper intertidal and supratidal zones. 11 refs., 6 tabs., 3 figs

  2. "Comparison of some Structural Analyses Methods used for the Test Pavement in the Danish Road Testing Machine

    DEFF Research Database (Denmark)

    Baltzer, S.; Zhang, W.

    1998-01-01

    A flexible test pavement, instrumented to measure stresses and strains in the three primary axes with the upper 400 mm of the subgrade, has been constructed and load tested in the Danish Road Testing Machine (RTM). One objective of this research, which is part of the International Pavement Subgrade Performance Study, is to develop an improved mechanistic subgrade failure criterion.Simulated traffic loads were applied between June and December 1997 by a dual tyre loading cart within a climate chamber maintained at a constant temperature. Three load levels (40 kN, 50 kN and 60 kN) were applied. In all three test series, 50000 load repetitions were applied at each load level, and the test chamber temperature was maintained at approximately 25 degree C.Instruments installed in the test pavement included: Strain measuring sensors (LVDT Soil Strain Deformation Transducers and Asphalt Strain Gauges), Soil Pressure Cells, Thermistors and Pore Pressure Sensors. Routine monitoring of instrument responses and surface profiles with a Profilometer and FWD/LWD structural testing were undertaken at regular intervals during the construction and load testing programmes.This paper compares various structural analysis methods used for the RTM test pavement with data from FWD testing undertaken after the construction and loading programmes. Multilayer linear elastic forward and backcalculation methods, a finite element program and MS Excel spreadsheet based methods are compared.

  3. The impact of light-colored pavements on active layer dynamics revealed by Ground-Penetrating Radar monitoring

    DEFF Research Database (Denmark)

    JØrgensen, Anders Stuhr; Ingeman-Nielsen, Thomas

    2008-01-01

    Ground-penetrating radar (GPR) has been used to study the variations in the depth of the frost table throughout a complete thaw-freeze season in Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white on the parking area of the airport in order to reduce further development of depressions in the asphalt pavement. One of these areas has been used in the GPR investigations to compare the variations of the frost table underneath a normal dark asphalt surface to that below a more reflective surface. The GPR results have shown a clear correlation between the use of the reflective surface and a reduced depth to frost table. In late summer the difference in the depths to the frost table is approximately 0.9 m. The results should promote the interest in the development and use of light colored pavement materials in order to reduce the effect of a warming climate on arctic infrastructures.

  4. Laboratory analysis of the infiltration capacity of interlocking concrete block pavements in car parks.

    Science.gov (United States)

    Sañudo-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

  5. Development of Improved Mechanistic Deterioration Models for Flexible Pavements

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ertman, Hans Larsen

    1998-01-01

    The paper describes a pilot study in Denmark with the main objective of developing improved mechanistic deterioration models for flexible pavements based on an accelerated full scale test on an instrumented pavement in the Danish Road Tessting Machine. The study was the first in "International Pavement Subgrade Performance Study" sponsored by the Federal Highway Administration (FHWA), USA. The paper describes in detail the data analysis and the resulting models for rutting, roughness, and a model for the plastic strain in the subgrade.The reader will get an understanding of the work needed to be done to be succesful in establishing mechanistic models based on Accelerated Load Testing (ALT) complemented by laboratory testing.

  6. Development of Mechanistic-Empirical Flexible Pavement Design in Iran

    Directory of Open Access Journals (Sweden)

    M. Ameri

    2009-01-01

    Full Text Available Recent advances in flexible pavement design have prompted agencies to move toward the development and use of Mechanistic-Empirical (M-E design procedures. Mechanistic-Empirical (M-E design combine the elements of mechanical modeling and performance observation in determining the required pavement thickness for a set of design condition. In this study, a Mechanistic-Empirical (M-E design procedures and algorithm based on KENLAYER software with regard to Iran climatic and traffic conditions is developed. This study also explores present relationships and diagrams based on effective variable on pavement design to facilitate design process.

  7. Climate change, energy, sustainability and pavements

    International Nuclear Information System (INIS)

    Provides an integrated perspective on understanding the impacts of climate change, energy and sustainable development on transportation infrastructure systems. Presents recent technological innovations and emerging concepts in the field of green and sustainable transportation infrastructure systems with a special focus on highway and airport pavements. Written by leading experts in the field. Climate change, energy production and consumption, and the need to improve the sustainability of all aspects of human activity are key inter-related issues for which solutions must be found and implemented quickly and efficiently. To be successfully implemented, solutions must recognize the rapidly changing socio-techno-political environment and multi-dimensional constraints presented by today's interconnected world. As part of this global effort, considerations of climate change impacts, energy demands, and incorporation of sustainability concepts have increasing importance in the design, construction, and maintenance of highway and airport pavement systems. To prepare the human capacity to develop and implement these solutions, many educators, policy-makers and practitioners have stressed the paramount importance of formally incorporating sustainability concepts in the civil engineering curriculum to educate and train future civil engineers well-equipped to address our current and future sustainability challenges. This book will prove a valuable resource in the hands of researchers, educators and future engineering leaders, most of whom will be working in multidisciplinary environments to address a host of next-generation sustainable transportation infrastructure challenges.

  8. Climate change, energy, sustainability and pavements

    Energy Technology Data Exchange (ETDEWEB)

    Gopalakrishnan, Kasthurirangan [Iowa State Univ., Ames, IA (United States). Dept. of Civil, Construction and Environmental Engineering; Steyn, Wynand JvdM [Pretoria Univ. (South Africa). Dept. of Civil Engineering; Harvey, John (ed.) [California Univ., Davis, CA (United States). Dept. of Civil and Environmental Engineering

    2014-07-01

    Provides an integrated perspective on understanding the impacts of climate change, energy and sustainable development on transportation infrastructure systems. Presents recent technological innovations and emerging concepts in the field of green and sustainable transportation infrastructure systems with a special focus on highway and airport pavements. Written by leading experts in the field. Climate change, energy production and consumption, and the need to improve the sustainability of all aspects of human activity are key inter-related issues for which solutions must be found and implemented quickly and efficiently. To be successfully implemented, solutions must recognize the rapidly changing socio-techno-political environment and multi-dimensional constraints presented by today's interconnected world. As part of this global effort, considerations of climate change impacts, energy demands, and incorporation of sustainability concepts have increasing importance in the design, construction, and maintenance of highway and airport pavement systems. To prepare the human capacity to develop and implement these solutions, many educators, policy-makers and practitioners have stressed the paramount importance of formally incorporating sustainability concepts in the civil engineering curriculum to educate and train future civil engineers well-equipped to address our current and future sustainability challenges. This book will prove a valuable resource in the hands of researchers, educators and future engineering leaders, most of whom will be working in multidisciplinary environments to address a host of next-generation sustainable transportation infrastructure challenges.

  9. "Full-Scale Testing of Pavement Response"

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ekdahl, Peter

    1998-01-01

    Three pavement sections in southern Sweden were instrumented in late 1991. Each section have instruments for measuring the strain at the bottom of the asphalt layer, vertical stress and strains in the subgrade and temperatures at different depths. The purpose was to evaluate different theoretical methods for determining stresses, strains and deflections in pavement structurers.Falling Weight Deflectometer (FWD) test were done on the test sections, and stresses and strains were measured both under FWD loading and under a rolling wheel load. Different back-analysis procedures were used to derive layer moduli from FWD testing. The forward calculated stresses and strains were then compared to the measured values. The tests were done under different climatic conditions, the latest in November 1996, where almost all of the gauges were still functioning.Of the different methods used for back-analysing FWD data and for calculating the stresses and the strains, the simple method based on Odemark's transformations and Boussinesq's equations appeared to be as good as, or better than, the more sophisticated methods using layered elastic theory or the Finite Element Method.

  10. Data Analysis Report : Preliminary Test Pavement Danish Road Testing Machine

    DEFF Research Database (Denmark)

    Ullidtz, Per; Zhang, Wei

    1997-01-01

    Main conclusions: 1) The Asphalt Strain Gauges (ASG), the Soil Deformation Transducers (SDT) and the Soil Pressure Cells (SPC) performed well during the experiment, but the SPCs need frequent in situ calibration. A different installation procedure for the SPCs should be considered. Due to the variability of the soil more instruments (than two) are needed for each response value to be determined. 2) Strains measured using the emu coils did not have a satisfactory degree of accuracy. Laboratory tests showed the Kulite pressure cells to be dependent upon loading history and soil stiffness. For this reason the cells were not used in the RTM experiment. The volumetric moisture content recorded by the VITEL moisture probes did not appear to be reliable. 3) Linear elastic theory did not give a satisfactory agreement with measured stresses and strains. The measured vertical strains could be several times larger than the theoretical values. Elsym5 seems to produce incorrect deflections in some cases. 4) Satisfactory agreement between measured and theoretical stresses and strains could be obtained using the Finite Element Method and appropriate non-linear relationships for the moduli of the unbound materials. 5) The variation of stresses and strains with distance from the load was found to be in very good agreement with Boussinesgs equations, with the exception of the horizontal stress. The relationship between the depth used with Boussinesq's equations the the actual depth needs further study. 6) The subgrade showed thixotropyc behavior with strains increasing with the number of load repetitions and decreasing after a rest period. This behavior was only observed under the wheel load, not under the FWD. 7) Existing design criteria for subgrades appear to be reasonable when used with strains calculated using linear elastic theory and moduli determined from FWD tests, but ar much too conservative if used with measured strains. 8) Plastic strain in the subgrade, surface rutting and roughness could all be related to the measured resilient strain at the top of the subgrade, with damage being proportional to the load raised to a power between 6.23 and 6.67. These relationships can be used to calculate the pavement condition after a given number of loads or to determine the permissible number of loads for a given terminal condition of the pavement. For surface rutting and roughness the contribution from the individual layers could not be established.

  11. Cortico-limbic morphology separates tinnitus from tinnitus distress

    Directory of Open Access Journals (Sweden)

    AmberMLeaver

    2012-04-01

    Full Text Available Tinnitus is a common auditory disorder characterized by a chronic ringing or buzzing “in the ear.” Despite the auditory-perceptual nature of this disorder, a growing number of studies have reported neuroanatomical differences in tinnitus patients outside the auditory-perceptual system. Some have used this evidence to characterize chronic tinnitus as dysregulation of the auditory system, either resulting from inefficient inhibitory control or through the formation of aversive associations with tinnitus. It remains unclear, however, whether these “non-auditory” anatomical markers of tinnitus are related to the tinnitus signal itself, or merely to negative emotional reactions to tinnitus (i.e., tinnitus distress. In the current study, we used anatomical MRI to identify neural markers of tinnitus, and measured their relationship to a variety of tinnitus characteristics and other factors often linked to tinnitus, such as hearing loss, depression, anxiety, and noise sensitivity. In a new cohort of participants, we confirmed that people with chronic tinnitus exhibit reduced grey matter in ventromedial prefrontal cortex (vmPFC compared to controls matched for age and hearing loss. This effect was driven by reduced cortical surface area, and was not related to tinnitus distress, symptoms of depression or anxiety, noise sensitivity, or other factors. Instead, tinnitus distress was positively correlated with cortical thickness in the anterior insula in tinnitus patients, while symptoms of anxiety and depression were negatively correlated with cortical thickness in subcallosal anterior cingulate cortex (scACC across all groups. Tinnitus patients also exhibited increased gyrification of dorsomedial prefrontal cortex (dmPFC, which was more severe in those patients with constant (vs. intermittent tinnitus. Our data suggest that the neural systems associated with chronic tinnitus are different from those involved in aversive or distressed reactions to tinnitus.

  12. How Is Respiratory Distress Syndrome Treated?

    Science.gov (United States)

    ... that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Respiratory Distress Syndrome, visit www.clinicaltrials.gov . Visit Children ...

  13. 46 CFR 28.145 - Distress signals.

    Science.gov (United States)

    2010-10-01

    ...VESSELS REQUIREMENTS FOR COMMERCIAL FISHING INDUSTRY VESSELS Requirements for All...of the coastline on the Great Lakes Night visual distress signals consisting...counted toward meeting both the day and night requirement. [CGD 88-079, 56...

  14. CAUSES OF RESPIRATORY DISTRESS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    M M Karambin

    2008-11-01

    Full Text Available "nThere is a lack of large, prospective epidemiologic studies concerning acute lung injury (ALI and acute respiratory distress syndrome (ARDS in pediatric population. To determine the different causes of respiratory distress in children, we prepared a retrospective study and included the whole 567 children with respiratory distress referred to 17-Shahrivar Hospital, Rasht, Guilan. Using their medical files, data including age, sex, and causes of respiratory distress were collected. SPSS 13.0 (statistical software applied for statistical analysis. Pneumonia, asthma, and croup were the major causes of ARDS in children with a rate of 38.4, 19.04, and 16.5 percent, respectively. It seems that infectious factors are at the top of the list of ARDS causing factors which can be helpful to approach and manage such patients. We suggest vaccinating these at risk groups against common infectious factors such as H. Influenza and RSV which can cause either pneumonia or inducing asthma.

  15. Permeable Pavement Demonstration at the Edison Environmental Center - Poster

    Science.gov (United States)

    Poster for the SAB Review detailing the porous pavement parking lot project. The poster describes the design of the parking lot, the research components that were incorporated into the design, and the monitoring plan....

  16. Interpersonal relationships and emotional distress in adolescence

    OpenAIRE

    Kenny, Rachel; Dooley, Barbara A.; Fitzgerald, Amanda

    2013-01-01

    The aim of this study was to examine positive and negative qualities in adolescents' interpersonal relationships and their relative importance in predicting emotional distress. Participants were 260 students from three schools in the Dublin area (119 girls; 141 boys), aged 12-18 years (M = 15.32, SD = 1.91). Students completed questionnaires assessing qualities in important interpersonal relationships in their lives and emotional distress. Girls reported more p...

  17. Deposit Withdrawals from Distressed Commercial Banks

    OpenAIRE

    Martin Brown; Stefan Morkötter; Benjamin Guin

    2014-01-01

    We study retail deposit withdrawals from European commercial banks which incurred investment losses in the wake of the U.S. subprime crisis. We document a strong propensity of households to withdraw deposits from distressed banks, especially when a bank receives a public bailout. However, the withdrawal risk for a distressed bank is mitigated by strong bank-client relationships and household-level switching costs: Households which rely on a single deposit account, which do not live close to a...

  18. Effect Of Geopathic Stress On Bituminous Pavement

    OpenAIRE

    Chafekar, B. H.; Jarad, G. P.; Pimplikar, S. S.; Kharat, A. G.; Dharmadhikari, N. P.; Sorate, R. R.

    2013-01-01

    This paper basically for the investigation of Geopathic Stress Zones along the road. Geopathic stress is detrimental energy emanating from the earth and leading to long-term harm to susceptible humans, animals and plants which are exposed to them in their environment. Detection of geopathic location has been done by Experimental investigations on road alignment of one KM, by performing distresses survey, dowsing and by magnetic field detector to investigate the Geopathic Stress. Due to such e...

  19. Pavement macrotexture estimation using principal component analysis of tire/road noise

    Science.gov (United States)

    Zhang, Yiying; McDaniel, J. Gregory; Wang, Ming L.

    2014-04-01

    An investigation on the prediction of macrotexture Mean Texture Depth (MTD) of pavement from a moving vehicle is conducted. The MTD was predicted by using the tire/road noise measured from a microphone mounted underneath a moving vehicle. Principal Component Analysis (PCA) is used to filter noise from microphone data prioer to estimating its energy over an optimally selected bandwidth. Energy obtained using this method is named PCA energy, hence the developed method for MTD estimation is termed as PCA Energy Method. The acoustic energy is assumed to have positive linear correlation with MTD of pavement. Moreover, PCA was used to differentiate important information about the road surface from noisy data while vehicle is moving, yielding a set of principal component vectors representing the conditions of each road section. This principal component vector was used to compute the PCA energy that is to be used for MTD prediction. The frequency band most relative to pavement macrotexture was determined to be 140 to 700 Hz through theoretical and statistical research. Then, a MTD prediction model was built based on a Taylor series expansion with two variables, PCA energy and the driving speed of the vehicle. The model parameters were obtained from an engineered track (interstate highway) with known MTD, and then applied to urban roads for the feasibility test. The accuracy of the model is 83.61% for the engineered track, which is 10% higher than the previous energy-based methods without PCA treatment. Moreover, applicability of the model is increased by the extended MTD prediction range between 0.2 and 3 mm compared to that of the engineered track having 0.4 to 1.5 mm. In addition, the MTD could be predicted every 7.8 meters and with good repeatability in the urban road test, which proves the feasibility of the proposed approach. Therefore, the PCA Energy Method is a reliable, efficient, and cost effective way to predict MTD for engineering applications as an important index for pavement friction prediction and pavement segregation identification.

  20. Finite Element Investigation of the Deterioration of Doweled Rigid Pavements

    OpenAIRE

    Ghauch, Ziad G.

    2011-01-01

    The purpose of this study is to describe the failure of concrete around dowel bars in jointed rigid pavements, and the resulting effect on the pavement performance. In fact, under repetitive vehicle loading, concrete in contact with the dowel bar deteriorates, particularly at the joint face. The degradation of concrete around the dowel negatively affects the latter's performance in terms of transferring wheel loads through vertical shear action. In this context, a nonlinear ...

  1. Technical-economical evaluation of pavement recycling alternatives

    OpenAIRE

    Pereira, Paulo A. A.; Santos, Luís Picado

    2006-01-01

    Pavement recycling is becoming an increasingly important alternative worldwide for maintenance of highways, once sustainability and environmental issues have continued to receive more attention. The reference point is that of considering the use of road materials in a closed cycle, in which a natural material, previously used in road construction, should not be rejected in the following life-cycle. The objective of this paper is that of analysing flexible pavement recycling alternatives techn...

  2. Shear Fatigue Behaviour of Tack Coats in Pavements

    OpenAIRE

    Diakhaté, Malick; Phelipot-Mardelé, Annabelle; Millien, Anne; Petit, Christophe

    2006-01-01

    For many years, pavement engineers use mechanistic design methods that are based on algorithms to compute stresses, strains and displacements in a flexible pavement structure, or in a multi-layered structure in general. Most of these methods assume, to ease the modelling of the structure and the computation process, that the layers are fully bonded or completely unbounded to each other. Moreover, determining the effectiveness of the bonding between two layers is difficult since there is no st...

  3. A contribution to assess he structural vulnerability timber pavements

    OpenAIRE

    Teixeira, Marcos; Ferreira, De?bora; Cunha, Victor; Feio, Artur; Lousada, Jose?; Varum, Humberto; Guedes, Miranda; Pinto, Jorge

    2013-01-01

    In general, timber pavements are the main horizontal structural elements of the Portuguese traditional buildings. Since these types of buildings required to be preserved, the maintenance of timber pavements is crucial. However and unfortunately, the demolition of the interior of traditional buildings still is a current building option in rehabilitation processes. This building scenario is more expressive in private estate, in particular, in private dwellings. This option may be due to the ...

  4. Evaluation of Common Maintenance Methods for Flexible Pavements

    OpenAIRE

    Ibraheem, Asma T.; Gani, Suda M.

    2011-01-01

    Problem statement: With the increasing use and awareness of pavement management systems and the growing emphasis on asset management of pavement infrastructure, it is important to strengthen the maintenance components of these systems and particularly the preventive maintenance component. Iraqi Roads don?t receive an effective and proper maintenance during their service life until they reach the state of major failure that requires rehabilitation. Roads in Iraq are being lost. Approach: In t...

  5. / Distress, demoralization and psychopathology: Diagnostic boundaries

    Scientific Electronic Library Online (English)

    John M. de, Figueiredo.

    2013-03-01

    Full Text Available Background and Objectives: The objectives of the manuscript are: (a) to review the understanding of demoralization and its assessment; (b) to describe its clinical progression; (c) to explain the differences between demoralization and other form of psychological distress; (d) to propose a set of cri [...] teria for future research on demoralization. Methods: A MEDLINE search using the keywords distress, subjective incompetence, depression, demoralization, helplessness, hopelessness and psychopathology was conducted. This was supplemented by a manual search of the literature. Results: Demoralization can be distinguished from passing or transient distress, non-specific distress, sub-threshold depression or anxiety, and certain mental disorders. Demoralization can be a risk factor for the manifestation of psychopathology, the prodromal phase of a mental disorder, or a trigger for exacerbation or recurrence of psychiatric distress symptoms. The domains of distress and demoralization are described and research diagnostic criteria for demoralization are presented. Conclusions: The scales discussed in this article differ in their time frames and have not yet been applied to the same population at the same time. The role of demoralization as a risk factor for mental disorders is just beginning to be understood. The domains and the diagnostic criteria for demoralization presented in this article need to be confirmed by epidemiological and empirical studies. Future research should continue to clarify its role in the pathogenesis of both mental disorders and physical illnesses and identify appropriate interventions for its arrest or prevention.

  6. Pulmonary distress following attempted suicidal hanging

    Directory of Open Access Journals (Sweden)

    Nair Shalini

    2009-02-01

    Full Text Available Objective : To assess the incidence of post-hanging pulmonary distress in cases of attempted suicidal hanging and predictors of outcome among these patients. Design : Five-year retrospective analysis. Setting: Tertiary care center in south India. Patients :A total of 335 patients who attempted suicidal hanging, aged above 16 years, were admitted during this period. Thirty-eight of them with pulmonary distress established clinically and with radiological evidence of pulmonary injury post hanging met the inclusion criteria. Measurements : Data from ICU records of 5 years, X-rays and laboratory investigations were reviewed. In patients identified to have post-hanging pulmonary distress, the neurological status, chest x-rays, arterial blood gas values and outcome data were collected and analyzed. Results : Eleven percent (n = 38 of the 335 patients admitted following attempted suicidal hanging were diagnosed to have post-hanging pulmonary distress. The overall mortality among post-hanging patients was 5%, which increased to 34.2% (n = 13 in the presence of pulmonary distress (P ? 0.001. Among the prognostic factors evaluated, a PaO 2 / FiO 2 (P/F ratio of < 100 at admission predicted a poor outcome (P ? 0.001. Conclusion : Post-hanging pulmonary distress is a relatively common complication of hanging and is associated with increased mortality. P/F ratio from arterial blood gas at admission was the only significant predictor of outcome in this group of patients.

  7. Effects of rejuvenator seal and fog seal on performance of open-graded friction course pavement

    Directory of Open Access Journals (Sweden)

    Nadeem A. Qureshi

    2013-05-01

    Full Text Available An open-graded friction course (OGFC is a special-purpose surface layer of hot-mix asphalt (HMA pavement that is increasingly being used around the world. Owing to its numerous benefits, OGFC is being regularly used as a final riding surface on interstate and high-traffic expressways by different highway agencies in the United States. However, some OGFC sections have experienced premature failure due to ravelling only after 6-8 years of service life. To maintain an effective, longer service life and enhanced performance of OGFC, preventive maintenance has been considered essential. There are several approaches to maintaining OGFC, one of which is the application of a fog seal and rejuvenator seal. A fog seal can reduce ravelling and extend the service life of OGFC while a rejuvenator seal can revitalise the existing aged asphalt binder in the top OGFC layer. This research focuses on optimising the fog and rejuvenator seal application rates by evaluating their effectiveness in terms of surface friction and durability. Three types of seal material were evaluated: Pavegaard (PG and Pavepreserve (PP asphalt rejuvenators and a cationic slow-setting asphalt emulsion (CSS-1H as a fog seal. Improvement in abrasion resistance of OGFC pavement was observed on application of fog and rejuvenator seals but surface friction was reduced to some extent. Hamburg test clearly shows a trend that the medium application rate of 0.10 gallon/square yard is better in enhancing resistance to rutting/moisture susceptibility of OGFC.

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

    Science.gov (United States)

    Sañudo-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

  9. The development and geometry of shape change in Arabidopsis thaliana cotyledon pavement cells

    OpenAIRE

    Halsey Leah E; Zhang Chunhua; Szymanski Daniel B

    2011-01-01

    Abstract Background The leaf epidermis is an important architectural control element that influences the growth properties of underlying tissues and the overall form of the organ. In dicots, interdigitated pavement cells are the building blocks of the tissue, and their morphogenesis includes the assembly of specialized cell walls that surround the apical, basal, and lateral (anticlinal) cell surfaces. The microtubule and actin cytoskeletons are highly polarized along the cortex of the anticli...

  10. Depression storage capacities of different ideal pavements as quantified by a terrestrial laser scanning-based method.

    Science.gov (United States)

    Nehls, T; Menzel, M; Wessolek, G

    2015-01-01

    Rainfall partition on paved urban surfaces is governed to a great extent by depression storage. This is especially the case for small rainfall events, which are often ignored in urban hydrology. If storage, infiltration and evaporation (important for urban heat island mitigation), rather than storm water run-off, are of interest, high-resolution simulations with exact values for depression storage capacities are required. Terrestrial laser scanners deliver fast, high-resolution surveys of pavement surface morphology. The depression storage capacity can be quantified from 3D points by generating digital elevation models and applying cut-and-fill algorithms in a geographic information system. The method was validated using a test model. It was possible to quantify depressions with a depth of at least 1.4 × 10(-3) m and a surface of at least 15 × 10(-6) m(2) with an uncertainty below 30%. Applying this method, the depression storage capacities for 11 ideal, typical pavement designs were found to vary from 0.07 to 1.4 mm. Realistic urban pavements must also be surveyed, as cracks and puddles from their use history can have a major impact on the depression storage capacities and thus on infiltration, evaporation and, finally, the annual run-off. PMID:25812095

  11. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 970.208 Section...National Park Service Management Systems § 970.208 Federal lands pavement management system (PMS). In addition to...

  12. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 972.208 Section...and Wildlife Service Management Systems § 972.208 Federal lands pavement management system (PMS). In addition to...

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

    Science.gov (United States)

    2010-04-01

    ...2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 971.208 Section...Forest Highway Program Management Systems § 971.208 Federal lands pavement management system (PMS). In addition to...

  14. POROUS PAVEMENT PHASE I DESIGN AND OPERATIONAL CRITERIA (EPA/600/2-80/135)

    Science.gov (United States)

    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 ...

  15. PAH volatilization following application of coal-tar-based pavement sealant

    Science.gov (United States)

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-05-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (?PAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 lost to the atmosphere on the basis of air sampling (2-3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ?PAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (?1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  16. PAH volatilization following application of coal-tar-based pavement sealant

    Science.gov (United States)

    Van Metre, Peter C.; Majewski, Michael S.; Mahler, Barbara J.; Foreman, William T.; Braun, Christopher L.; Wilson, Jennifer T.; Burbank, Teresa L.

    2012-01-01

    Coal-tar-based pavement sealants, a major source of PAHs to urban water bodies, have recently been identified as a source of volatile PAHs to the atmosphere. We tracked the volatilization of PAHs for 1 year after application of a coal-tar-based pavement sealant by measuring gas-phase PAH concentrations above the pavement surface and solid-phase PAH concentrations in sealant scraped from the surface. Gas-phase concentrations at two heights (0.03 and 1.28 m) and wind speed were used to estimate volatilization flux. The sum of the concentrations of eight frequently detected PAHs (?PAH8) in the 0.03-m sample 1.6 h after application (297,000 ng m-3) was about 5000 times greater than that previously reported for the same height above unsealed parking lots (66 ng m-3). Flux at 1.6 h after application was estimated at 45,000 ?g m-2 h-1 and decreased rapidly during the 45 days after application to 160 ?g m-2 h-1. Loss of PAHs from the adhered sealant also was rapid, with about a 50% decrease in solid-phase ?PAH8 concentration over the 45 days after application. There was general agreement, given the uncertainties, in the estimated mass of ?PAH8 lost to the atmosphere on the basis of air sampling (2–3 g m-2) and adhered sealant sampling (6 g m-2) during the first 16 days after application, translating to a loss to the atmosphere of one-quarter to one-half of the PAHs in the sealcoat product. Combining the estimated mass of ?PAH8 released to the atmosphere with a national-use estimate of coal-tar-based sealant suggests that PAH emissions from new coal-tar-based sealcoat applications each year (~1000 Mg) are larger than annual vehicle emissions of PAHs for the United States.

  17. Design of Rigid and Flexible Pavements by Various Methods & Their Cost Analysis of Each Method

    OpenAIRE

    Saurabh Jain

    2013-01-01

    Highway and pavement design plays an important role in the DPR projects. The satisfactory performance of the pavement will result in higher savings in terms of vehicle operating costs and travel time, which has a bearing on the overall economic feasibility of the project. This paper discusses about the design methods that are traditionally being followed and examines the “Design of rigid and flexible pavements by various methods & their cost analysis by each method”. Flexible pavement are...

  18. Moisture Influence on Structural Behaviour of Pavements : Field and Laboratory Investigations

    OpenAIRE

    Salour, Farhad

    2015-01-01

    The structural behaviour of pavements in cold regions can considerably be affected by seasonal variation in environmental factors such as temperature and moisture content. Along with the destructive effect of heavy traffic loads, climatic and environmental factors can considerably contribute to pavement deterioration. These factors can influence the structural and functional capacity of the pavement structures which, as a result, can trigger and accelerate pavement deterioration mechanisms. S...

  19. Deterioration Forecasting in Flexible Pavements Due to Floods and Snow Storms

    OpenAIRE

    Shahini Shamsabadi, Salar; Hashemi Tari, Yasamin Sadat; Birken, Ralf; Wang, Ming

    2014-01-01

    Roadway agencies and state DOTs utilize Pavement Management Systems (PMS) to implement cost-effective maintenance strategies. A reliable yet easily applicable model for deterioration process of pavements is an integral part of any Pavement Management System. As pavement condition grows to be one of the crucial problems facing our nation, the reliability of these deterioration prediction models becomes more important. While numerous endevours have been made to capture the effect of the environ...

  20. Evaluation of Road Pavement Density Using Ground Penetrating Radar

    Directory of Open Access Journals (Sweden)

    RSA Raja Abdullah

    2009-01-01

    Full Text Available This study describes an analysis of Ground Penetrating Radar (GPR measurements at frequency range of 1.7-2.6 GHz to get a relationship between attenuation and density for nine road pavements slabs with different densities. There are about four different frequencies had been tested. The method is simple, fast, non-destructive and accurate way to determine the density of road pavement. Density is a one of the important parameter in order to determine the compressive strength of road pavement for road user safety. In laboratory, the measurement system consists of a signal generator (250 kHz-3 GHz as a source, spectrum analyzer (100 Hz-8 GHz, directional coupler with adapter and horn antenna. The first part of the measurement system setup is to determine the amplitude of transmitted wave (received signal strength. A few of received signal strength and attenuation for nine road pavement slab samples were taken at four different frequencies. An instantaneous method for measuring the density of road pavement was developed by using microwave reflection technique and free space method. The MATLAB software is used to analyze the measurement data and also for the graphs comparisons. At the end of this study, it is found that density plays an important factor in causing a major in the recorded signal strength as well as the differences of attenuation of the GPR signal.

  1. Bearing capacity evaluation of rubblized concrete pavements

    Directory of Open Access Journals (Sweden)

    González, M.

    2009-03-01

    Full Text Available The paper presents the findings of a research work performed on a real scale concrete pavement project where Rubblizing technology was used for its structural rehabilitation. Rubblizing may be defined as a fracture technique in which a concrete pavement slab is transformed in a granular base with a very high Modulus. This technique, fractures the concrete slab in angular pieces by using a concentrated dynamic load of low amplitude and high frequency. The research work was based on field study on the rehabilitation of 5 km motorway. The structural evaluations where made, before, during and after one year construction. Measurements and site evaluation where made by using DCP, Light Weight Deflectometer and FWD (on top of asphalt layer and excavating inside pits. The structural capacity of the Rubblized layer was evaluated through theoretical analysis. Because of the anisotropic properties of the Rubblized layer the results are presented using AASHTO structural layer coefficient. The structural layer coefficients recommended are between the range of 0.25 and 0.30 for concrete slabs with thickness grater than 220 mm.El trabajo presenta los resultados de un estudio a escala real de la capacidad estructural de un firme de hormigón rehabilitado utilizando la técnica de Rubblizing. La técnica de Rubblizing ha sido traducida como el pulverizado del firme de hormigón pero, es más bien un efecto combinado de trituración y fracturación de la losa de hormigón en todo su espesor para convertir esta en una base granular de alto módulo. Esta tecnica fractura la losa de hormigón en trozos angulares y entrelazados empleando una carga dinámica concentrada, de baja amplitud y alta frecuencia. La investigación se basó en el estudio de la rehabilitación de 5 km de autopista. Los estudios de la capacidad estructural fueron realizados durante, al término y un año después de la construcción. Para las mediciones y evaluaciones de terreno se utilizó, el DCP, Deflectómetro de Impacto Liviano, FWD (sobre carpeta asfáltica y excavando calicatas bajo el material triturado. La capacidad estructural del material triturado se realizó a través de un análisis teórico. Debido al las características anisotrópicas del material triturado, los resultados son presentados utilizando el coeficiente estructural AASHTO. Los resultados del estudio permiten recomendar un rango para el coeficiente estructural del pavimento sometido al proceso de Rubblizing el cual para espesores de losa superior a 22 cm está entre 0,25 a 0,30.

  2. Seismic monitoring of roadbeds for traffic flow, vehicle characterization, and pavement deterioration

    Energy Technology Data Exchange (ETDEWEB)

    Elbring, G.J.; Ormesher, R.C.; Holcomb, D.J.

    1998-01-01

    A road-side seismic monitoring system has been developed that includes not only instrumentation and fielding methods, but also data analysis methods and codes. The system can be used as either a passive or active monitoring system. In the passive mode, seismic signals generated by passing vehicles are recorded. Analysis of these signals provides information on the location, speed, length, and weight of the vehicle. In the active mode, designed for monitoring pavement degradation, a vibrating magnetostrictive source is coupled to the shoulder of the road and signals generated are recorded on the opposite side of the road. Analysis of the variation in surface wave velocity at various frequencies (dispersion) is used in an attempt to develop models of the near-surface pavement velocity structure. The monitoring system was tested at two sites in New Mexico, an older two-lane road and a newly-paved section of interstate highway. At the older site, the system was able to determine information about vehicle velocity, wheel-base length and weight. The sites showed significant differences in response and the results indicate the need for further development of the method to extract the most information possible for each site investigated.

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

    Science.gov (United States)

    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

  4. Artificial intelligence modeling to evaluate field performance of photocatalytic asphalt pavement for ambient air purification.

    Science.gov (United States)

    Asadi, Somayeh; Hassan, Marwa; Nadiri, Ataallah; Dylla, Heather

    2014-01-01

    In recent years, the application of titanium dioxide (TiO?) as a photocatalyst in asphalt pavement has received considerable attention for purifying ambient air from traffic-emitted pollutants via photocatalytic processes. In order to control the increasing deterioration of ambient air quality, urgent and proper risk assessment tools are deemed necessary. However, in practice, monitoring all process parameters for various operating conditions is difficult due to the complex and non-linear nature of air pollution-based problems. Therefore, the development of models to predict air pollutant concentrations is very useful because it can provide early warnings to the population and also reduce the number of measuring sites. This study used artificial neural network (ANN) and neuro-fuzzy (NF) models to predict NOx concentration in the air as a function of traffic count (Tr) and climatic conditions including humidity (H), temperature (T), solar radiation (S), and wind speed (W) before and after the application of TiO? on the pavement surface. These models are useful for modeling because of their ability to be trained using historical data and because of their capability for modeling highly non-linear relationships. To build these models, data were collected from a field study where an aqueous nano TiO? solution was sprayed on a 0.2-mile of asphalt pavement in Baton Rouge, LA. Results of this study showed that the NF model provided a better fitting to NOx measurements than the ANN model in the training, validation, and test steps. Results of a parametric study indicated that traffic level, relative humidity, and solar radiation had the most influence on photocatalytic efficiency. PMID:24699867

  5. Geo synthetic-reinforced Pavement systems; Sistemas de pavimentos reforzados con geosinteticos

    Energy Technology Data Exchange (ETDEWEB)

    Zornberg, J. G.

    2014-02-01

    Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

  6. Reduction in mental distress among substance users receiving inpatient treatment

    OpenAIRE

    Friborg Oddgeir; Benum Vår; Hoxmark Ellen; Wynn Rolf

    2010-01-01

    Abstract Background Substance users being admitted to inpatient treatment experience a high level of mental distress. In this study we explored changes in mental distress during treatment. Methods Mental distress, as measured by the HSCL-10, was registered at admission and at discharge among 164 substance users in inpatient treatment in Northern Norway. Predictors of reduction in mental distress were examined utilizing hierarchical regression analysis. Results We found a significant reduction...

  7. Development of a distress inventory for cancer: preliminary results.

    OpenAIRE

    Thomas B; Mohan V; Thomas I; Pandey M

    2002-01-01

    CONTEXT: Advances in cancer treatment have led to cure and prolongation of patients? lives; however associated psychosocial problems, including distress, can detrimentally affect patients? compliance with treatment and ultimately, their outcome. Symptom distress has been well addressed in many studies; however, psychological distress has only been quantified by using depression or anxiety scales/checklists or quality of life scales containing a distress sub scale/component or by...

  8. Proportioning of Steel Fibre Reinforced Concrete Mixes for Pavement Construction and Their Impact on Environment and Cost

    OpenAIRE

    Stelios Kallis; Neophytou, Pavlos O.; Kypros Pilakoutas; Kyriacos Neocleous; Diofantos Hadjimitsis; Constantia Achilleos

    2011-01-01

    Steel fibre reinforced concrete (SFRC) is a construction material investigated for more than 40 years including for pavement applications. A number of studies have demonstrated the technical merits of SFRC pavements over conventional concrete pavements; however little work has been carried out on the environmental and economical impact of SFRC during the pavement’s life cycle. Therefore, extended research was undertaken within the framework of the EU funded project “EcoLanes” to estimat...

  9. Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements

    Directory of Open Access Journals (Sweden)

    Tarefder R.

    2013-01-01

    Full Text Available This study evaluates airfield pavements’ functional- and structural-condition to determine the most economical maintenance method. As a part of the analysis, Pavement Condition Index (PCI for several runways, taxiways, and aprons has been determined by MicroPAVER. Structural evaluation of airport pavements has been performed by Falling Weight Deflectometer (FWD test. Evaluation of Layer Moduli and Overlay Design (ELMOD also determines the required overlay thickness based on the E-values, i.e. FWD data analysis. Damage analysis determines the time of repeated overlay application. In addition, functional parameters have been included to determine the time of functional maintenance. Maintenance and rehabilitation alternatives have been selected to develop different program strategies. Life Cycle Cost Analysis (LCCA has been performed to determine the maintenance cost. Structural condition based maintenance cost is compared to functional condition based maintenance cost. Comparison shows that structural condition based approach yields cheaper maintenance strategies than functional condition based maintenance approach.

  10. Asphalt Pavement Material Improvement: A Review

    Directory of Open Access Journals (Sweden)

    Mohamed Sulyman

    2014-10-01

    Full Text Available The recycling of solid industrial wastes (SIW such as waste rubber tires and plastics will not only solve the global environmental problem of these SIW but also act as very promising modifiers for the improvement of engineering characteristics of the asphalt pavement material. The present work was concerned with assisting the interested readers to be familiarized with the paving material asphalt-modifiers obtained from SIW by providing historical perspective on its first invention and development. The paper has also provided highlights on common processes of asphalt mixture production. It was also worth mentioning that there are two asphalt production technologies: the warm mix asphalt (WMA and hot mix asphalt (HMA technologies, and the various advantages of using each one. Additionally, the paper has provided the reader with an overview of a number of case studies which were conducted by scientists and researchers for serious attempting to reach development and capturing significant properties of incorporating SIWs in civil engineering represented by scarp tires in form of crumb rubber (CR, plastics (polymers in their different forms.

  11. Negative Emotions and Behaviors are Markers of Breakup Distress

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeanette

    2013-01-01

    Method: University students who experienced a recent romantic breakup were given several self-report measures and were then divided into high versus low breakup distress groups. Results: The high breakup distress versus the low breakup distress groups had higher scores on negative emotions scales including depression, anxiety and anger and…

  12. Emotional Distress in College Students: Faculty Guide for Referrals.

    Science.gov (United States)

    Western Carolina Univ., Cullowhee, NC. Counseling and Psychological Services.

    This guide presents advice for university faculty and professional staff members to help them understand and respond when students are in emotional distress. It includes a reference for signs of extreme stress and advice on how to intervene. Common causes of emotional distress are listed and warning signs of distress are given. Suggestions are…

  13. Evaluación de pavimentos y decisiones de conservación con base en sistemas de inferencia difusos / Pavement Evaluation and Maintenance Decisions Based on Fuzzy Inference Systems

    Scientific Electronic Library Online (English)

    Gloria Inés, Beltrán-Calvo; Miguel Pedro, Romo-Organista.

    2014-09-01

    Full Text Available Las decisiones de conservación y la vida remanente de pavimentos en servicio, dependen en buena parte de la condición estructural que exhiben durante su operación. Con el ánimo de proveer una metodología que permita caracterizar el pavimento de manera rápida, con los niveles de detalle que se deseen [...] , en este trabajo se plantean tres sistemas basados en la lógica difusa, para inferir la condición de rigidez y deterioro, así como las decisiones de conservación. Para esos fines, se utilizaron datos de auscultación no destructiva registrados en sistemas de pavimento de tres y cuatro capas, incluyendo estructuras tradicionales y estructuras invertidas (con capa de sub-base rigidizada). Las bases de datos incluyen información sobre magnitud y severidad de daños estructurales y parámetros e indicadores de rigidez, derivados de pruebas de deflexión por impacto. Los sistemas desarrollados, permitieron integrar directamente en la caracterización estructural de los pavimentos, tanto el conocimiento y criterios de expertos, como las variables de carácter subjetivo y cualitativo, que se utilizan comúnmente para describir los niveles de severidad del deterioro. Asimismo, permitieron expresar los resultados mediante palabras o adjetivos cuantificadores del lenguaje, facilitando su interpretación y comprensión. En virtud de los resultados alcanzados, resulta razonable concluir que los sistemas propuestos pueden utilizarse con confianza para evaluaciones rápidas y toma de decisiones a nivel global o detallado en corredores viales. Abstract in english The remaining service life and maintenance decisions of existing pavements are highly dependent on stiffness and deterioration conditions throughout their operation. A non-conventional fuzzy logic based methodology is proposed in this work to address the stiffness-deterioration condition and conserv [...] ation decisions, by means of three Fuzzy Inference Systems. Analysis were conducted using a database gathered from field tests performed on three and four layer pavement systems, that included traditional layer structuring and pavements having a subbase stiffer than their granular base. Information about layer thicknesses, magnitude and severity of structural distresses, and parameters and indicators derived from deflection testing by impulse load devices were used. The developed systems, allowed representing expert knowledge and linguistic variables of subjective and qualitative nature, commonly used to describe the severity levels of deterioration; thus they can be involved into structural characterization of pavements. Results were also expressed linguistically, to facilitate their interpretation and understanding. Based on the high quality of results obtained, it seems reasonable to conclude that the proposed systems could be used confidently for assessing and making decisions about pavement conservation, with low computational cost.

  14. Evaluation of Common Maintenance Methods for Flexible Pavements

    Directory of Open Access Journals (Sweden)

    Asma T. Ibraheem

    2011-01-01

    Full Text Available Problem statement: With the increasing use and awareness of pavement management systems and the growing emphasis on asset management of pavement infrastructure, it is important to strengthen the maintenance components of these systems and particularly the preventive maintenance component. Iraqi Roads don?t receive an effective and proper maintenance during their service life until they reach the state of major failure that requires rehabilitation. Roads in Iraq are being lost. Approach: In this study, a study of the status of maintenance methods for road pavements in Iraq with special reference to flexible pavements is presented. For this purpose, open and closed questionnaires were executed in Baghdad to investigate the status of road pavement maintenance in Iraq. Road maintenance offices as (Ministry of construction and Housing, State Corporation for Roads and Bridges, Amanat Baghdad, Project office, were included in the questionnaire to arrive at the level of maintenance and techniques followed to maintain paved road in Iraq. Results: The interviews carried out reveal that maintenance in Iraq has secondary importance, apparently with no special budget allocated for such important works. In addition the maintenance methods and techniques followed do not comply the developments and modern techniques. Conclusion/Recommendations: Poor and miss-management of maintenance works and activities leading to delays and accumulation of failure in the highway network that require unusual expenditures to repair and maintain the accumulated damages. Also shortages in resources allocated for maintenance works and this leads to the diversion of significant portion of the allocated fund for maintenance works toward purchasing of new, or additional equipment to be used for the construction of new roads. It is strongly recommended to design a planning system for management pavement maintenance of road network in Iraq and develop a particular failure criterion for roads in Iraq.

  15. Functionality Enhancement of Industrialized Optical Fiber Sensors and System Developed for Full-Scale Pavement Monitoring

    Directory of Open Access Journals (Sweden)

    Huaping Wang

    2014-05-01

    Full Text Available Pavements always play a predominant role in transportation. Health monitoring of pavements is becoming more and more significant, as frequently suffering from cracks, rutting, and slippage renders them prematurely out of service. Effective and reliable sensing elements are thus in high demand to make prognosis on the mechanical properties and occurrence of damage to pavements. Therefore, in this paper, various types of functionality enhancement of industrialized optical fiber sensors for pavement monitoring are developed, with the corresponding operational principles clarified in theory and the performance double checked by basic experiments. Furthermore, a self-healing optical fiber sensing network system is adopted to accomplish full-scale monitoring of pavements. The application of optical fiber sensors assembly and self-healing network system in pavement has been carried out to validate the feasibility. It has been proved that the research in this article provides a valuable method and meaningful guidance for the integrity monitoring of civil structures, especially pavements.

  16. Young children's representations of peers' distress: associations to children's social functioning and acceptance of distressed peers.

    Science.gov (United States)

    Bengtsson, Hans; Persson, Gun E B

    2007-06-01

    Children's mental representations of situations involving another child's distress were examined in two studies. Study 1 examined 3- to 7-year-old children's (n= 44) ideas about what victims and bystanders would think, feel and do in hypothetical situations. In Study 2, 7- to 8-year-olds (n= 40) described their own cognitive response to situations in which they were confronted with another's distress. In both studies, representational bias was examined in relation to children's display of prosocial and aggressive behavior and in relation to their acceptance of distressed peers. Although not entirely consistent, findings indicate that three types of representational biases are associated with low levels of considerate behavior and with relatively low acceptance of distressed peers: (a) mentally representing the victim's problem without giving thought to its implications for the victim, (b) significantly reducing the emotional significance of the problem and (c) exaggerating negative aspects of the problem. PMID:17518913

  17. Differences Between Experienced and Anticipatory Distress.

    Science.gov (United States)

    Sowa, Claudia J.; Barsanti, Anne, N.

    1986-01-01

    Examined differences between distress ratings of anticipated and experienced life events in 168 college students. Found gender differences and significant differences between perceived and experienced aversion across events predicting symptoms of stress, depression, anxiety, and somatic discomfort in occupational, social and familial situations.…

  18. Spiritual distress: integrative review of literature

    Directory of Open Access Journals (Sweden)

    Cristina Maria Galvão

    2008-07-01

    Full Text Available This study aims to identify concepts and clinical indicators that evidence spiritual distress in patients. Integrative review was the method adopted for the development of the study. In the initial stage, 82 studies were found in the following databases PUBMED, COCHRANE, CINAHL, LILACS and North American Nursing Diagnosis Association Conference Proceedings and 18 were selected. The descriptors used were spirituality and nursing diagnosis in addition to the term spiritual distress. Literature review (38.9% and articles with level of evidence IV (27.8% were the predominant types of study. The analysis of the articles revealed that the identified concepts of spiritual distress presented common and related elements to the human being subjective and individual response to life experiences, which harm the human spiritual dimension. Defining spiritual distress is a complex task since it depends on the perspective of those evaluating it, limiting in this way, its generalization. However, knowledge regarding the constructs that guide the understanding of human spirituality can base the nursing care in its spiritual dimension, thus providing theoretical support for the diagnosis.

  19. Spiritual distress: integrative review of literature

    Directory of Open Access Journals (Sweden)

    Erika Cássia Lopes Chaves

    2008-08-01

    Full Text Available This study aims to identify concepts and clinical indicators that evidence spiritual distress in patients. Integrative review was the method adopted for the development of the study. In the initial stage, 82 studies were found in the following databases PUBMED, COCHRANE, CINAHL, LILACS and North American Nursing Diagnosis Association Conference Proceedings and 18 were selected. The descriptors used were spirituality and nursing diagnosis in addition to the term spiritual distress. Literature review (38.9% and articles with level of evidence IV (27.8% were the predominant types of study. The analysis of the articles revealed that the identified concepts of spiritual distress presented common and related elements to the human being subjective and individual response to life experiences, which harm the human spiritual dimension. Defining spiritual distress is a complex task since it depends on the perspective of those evaluating it, limiting in this way, its generalization. However, knowledge regarding the constructs that guide the understanding of human spirituality can base the nursing care in its spiritual dimension, thus providing theoretical support for the diagnosis.

  20. Happiness and Death Distress: Two Separate Factors

    Science.gov (United States)

    Abdel-Khalek, Ahmed M.

    2005-01-01

    The aim of the present study was to explore the relationship between happiness and death distress (death anxiety, death depression, and death obsession) in 275 volunteer Kuwaiti undergraduates. They responded to the Oxford Happiness Inventory, the Death Anxiety Scale, the Arabic Scale of Death Anxiety, the Death Depression Scale-Revised, and the…

  1. Women's Feminist Consciousness, Anger, and Psychological Distress

    Science.gov (United States)

    Fischer, Ann R.; Good, Glenn E.

    2004-01-01

    The goal of this study was to bring together several lines of research and theory on women's feminist consciousness from psychology, sociology, and philosophy. Past literatures had suggested bivariate links between feminist identity development and psychological distress, feminist identity and anger, feminist identity and interpersonal conflict,…

  2. Disordered Eating and Psychological Distress among Adults

    Science.gov (United States)

    Patrick, Julie Hicks; Stahl, Sarah T.; Sundaram, Murali

    2011-01-01

    The majority of our knowledge about eating disorders derives from adolescent and young adult samples; knowledge regarding disordered eating in middle and later adulthood is limited. We examined the associations among known predictors of eating disorders for younger adults in an age-diverse sample and within the context of psychological distress.…

  3. Interlocking Paving Stones Pavement as a Solution to Marshy Roads

    Directory of Open Access Journals (Sweden)

    Oluwapelumi O. Ojuri

    2012-04-01

    Full Text Available This study is focused on the use of interlocking paving stones pavement for marshy roads and high groundwater table terrain. The permeable interlocking paving type of stones was used to combat intrusion of underground/saline water for the road of case study (Akin-Adesola Street, Victoria Island, Lagos. Hydrogeologic data, i.e., groundwater level information for marshy roads terrain including the area of case study was obtained in form of investigation hole/borehole data. Different scientific tests and researches put together show the effectiveness and durability of the modified exfiltration system type of permeable pavement for high ground water table terrain.

  4. Performance of waste tyre rubber on model flexible pavement

    Directory of Open Access Journals (Sweden)

    D. S. V. Prasad

    2009-08-01

    Full Text Available This paper investigates the performance of flexible pavement on expansive soil subgrade using gravel/flyash as subbase course with waste tyre rubber as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the gravel subbase shows better performance as compared to flyash subbase with different percentages of waste tyre rubber as reinforcing material. Cyclic load tests are also carried out in the laboratory by placing a circular metal plate on the model flexible pavements. It is observed that the maximum load carrying capacity associated with less value of rebound deflection is obtained for gravel reinforced subbase compared to flyash reinforced subbase.

  5. The use of the S.A.S.W. to evaluate the deterioration of pavement properties with increase in wheel loads

    OpenAIRE

    Engelbrecht, Johann C. (Johannes Cornelis), 1946-; Van de Ven, M.F.C.; Sadzik, E.

    2001-01-01

    Paper presented at the 20th Annual South African Transport Conference 16 - 20 July 2001 "Meeting the transport challenges in Southern Africa", CSIR International Convention Centre, Pretoria, South Africa. ABSTRACT: The application of a non-destructive test method for the determination of elastic properties of pavement layers and soil layers is being discussed. This method makes use of the seismic wave theory through the analysis of surface waves S A S W (Spectral analysis of surface waves....

  6. Mechanistic-empirical pavement design guide: features and distinctive elements / Mechanistic-empirical pavement design guide: características y elementos distintivos

    Scientific Electronic Library Online (English)

    Margarita, Martínez Díaz; Ignacio, Pérez.

    2015-04-01

    Full Text Available El objetivo de este artículo es describir los rasgos más característicos del método de diseño de firmes conocido como Mechanistic-Empirical Pavement Design Guide, así como compararlo con otras metodologías de renombre, destacando sus ventajas y desventajas. El MEPDG puede predecir con precisión la e [...] volución de los deterioros, ayudando por tanto a elegir el diseño más adecuado para el caso de firmes de nueva construcción, o a programar la conservación de los ya existentes. Tras analizar diferentes métodos de diseño y gestión de firmes, el MEPDG destaca como el más completo al ser el que tiene en cuenta un mayor número de factores que afectan al firme. Por ello algunos países fuera de EEUU ya han importado y calibrado este método, lo que al mismo tiempo permite a la comunidad científica llevar a cabo estudios comparativos y mejorar sus pequeñas deficiencias. Abstract in english This paper is aimed at describing the most distinctive features of the pavement design method known as Mechanistic-Empirical Pavement Design Guide and to compare it with other renowned methodologies, while emphasizing its advantages and disadvantages. The MEPDG can accurately predict damage evolutio [...] n, thus helping to choose the most appropriate design for new pavements or to schedule the conservation of the already existing ones. After analyzing different pavement design and management methods, the MEPDG stands out as the most comprehensive one as it takes into account and properly combines the greatest number of factors that affect the pavement. Therefore, some countries outside the USA have already imported and calibrated this method, what, at the same time, allows the scientific community to carry out comparative studies and improve its small deficiencies.

  7. Application of CalME incremental-recursive method to the evaluation of the structural condition as asphalt pavements; Aplicacion del metodo recursivo-incremental CalME a la evaluacion del estado estructural de los pavimentos bituminosas

    Energy Technology Data Exchange (ETDEWEB)

    Mateos Moreno, A.; Perez Ayuso, J.; Cadavid Jauregui, B.; Marron Fernandez, J. O.

    2011-07-01

    CalME procedure represents one of the most advanced tools for the design, of flexible pavements world-wide. It is an incremental-recursive method, which means that pavements service life must be divided into many time intervals where both structural integrity and environmental conditions can be regarded as constants. It also means that the damage calculated at the end of each interval must be considered as initial condition for the next one. The goal of this type of models is the prediction of the evolution of the different distress mechanisms. The advantages of incremental-recursive procedures versus classical analytical design are shown in this paper. Advantages are shown not only in terms of design, but also as a tool in order to support structural evaluation. In particular, the potential of asphalt fatigue model incorporated in CalME is presented. this model is initially calibrated in the laboratory, and it is then re-calibrated based on the actual performance observed from field deflection testing. The model provides a reliable prediction of the future evolution of the damage of the asphalt mixture. Fatigue model validation has been conducted based on the performance from several flexible sections evaluated in CEDEX full-scale pavements test track. (Author) 14 refs.

  8. Acute Toxicity of Runoff from Sealcoated Pavement to Ceriodaphnia dubia and Pimephales promelas.

    Science.gov (United States)

    Mahler, Barbara J; Ingersoll, Christopher G; Van Metre, Peter C; Kunz, James L; Little, Edward E

    2015-04-21

    Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ?10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application. PMID:25860716

  9. Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas

    Science.gov (United States)

    Mahler, Barbara J.; Ingersoll, Christopher G.; VanMetre, Peter C.; Kunz, James L.; Little, Edward E.

    2015-01-01

    Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ?10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application.

  10. Long-term salt marsh recovery and pavement persistence at Metula' spill sites

    International Nuclear Information System (INIS)

    Three coastal sites oiled from the 1974 'Metula' oil spill in the Strait of Magellan were revisited in May 1998 to document oiling conditions 23.5 years after the spill. The sites revisited are in the Punta Espora area. Two are salt marshes and the third, an inter-tidal asphalt pavement. It was found that the marshes were still oil covered and bare of vegetation in most sections, although the tilling conducted in 1993 resulted in substantial increases in the number of plants that were able to recolonize. Application of fertilizer without tilling of the surface of the oil had no effect. By 1998 the oil, although still present, was weathered to a rubbery consistency. The large, 550 m. long asphalt pavement that had formed on the mixed-sediment beach remained, and showed relatively little change. Chemical analysis of the asphalt indicated extremely high degradation, including even some of the highly biodegradation-resistant biomarker compounds. The experimental treatment plots that were tilled in 1993 showed the highest level of weathered oil, and the highest degree of plant recolonization, suggesting that recolonization of the marshes could have been accelerated had tilling been conducted on these sites soon after the spill. 15 refs., 5 tabs., 6 figs

  11. Psychological distress among women with newly diagnosed breast cancer

    DEFF Research Database (Denmark)

    Mertz, Birgitte; Bistrup, Pernille Envold

    2012-01-01

    PURPOSE: Psychological distress is common in the cancer continuum. Our objectives were to determine the prevalence of distress and to investigate the related problems and the characteristics of women with breast cancer who experienced psychological distress at the time of diagnosis. METHODS: We used cross-sectional data from a questionnaire study. Women with newly diagnosed breast cancer were consecutively invited to respond before breast surgery. Between October 2008 and October 2009, a total of 357 responded out of 426 (84%) invited. Among these, 343 patients completed the 'distress thermometer' to measure psychological distress and the accompanying 'problem list' to identify related problems. Logistic regression models with 95% confidence intervals were used to estimate the associations between psychological distress, age, social support and domains on the problem list. RESULTS: With a cut-off of 3 on the distress thermometer, 77% of women with breast cancer reported distress, whereas when the cut-off was 7, 43% were distressed. The mean distress score was 5.4 (SD, 3.1). The most frequently reported problems were worry (77%) and nervousness (71%). Distress was significantly associated with the total score and three domains on the problem list. Younger women (

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

    Science.gov (United States)

    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.

  13. Evaluation of the visco-elastic properties in asphalt rubber in conventional mixtures

    OpenAIRE

    Minhoto, Manuel; Pereira, Paulo; Pais, Jorge

    2007-01-01

    Flexible pavements are subjected to a set of degradations on the pavement surface, such as cracks and other specific types of distress which arise from traffic and temperature variations and which are responsible for the users’ unsafety and discomfort. The occurrence of temperature variations in the pavement leads to a severe aggravation of the reflective cracking phenomenon what implies a premature distress of the overlays. In this way, a theoretical study about the influ...

  14. Exploring pavement crack evaluation with bidimensional empirical mode decomposition

    Science.gov (United States)

    Ayenu-Prah, Albert; Attoh-Okine, Nii

    2007-04-01

    Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD), a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decomposition (EMD), which can decompose non-linear and non-stationary signals into basis functions called intrinsic mode functions (IMF). IMFs are monocomponent functions that have well defined instantaneous frequencies. EMD is a sifting process that is non-parametric and data-driven; it does not depend on an a priori basis set. It is able to remove noise from signals without complicated convolution processes. BEMD decomposes an image into two-dimensional IMFs. The present paper explores pavement crack detection using BEMD together with the Sobel edge detector. A number of images are filtered with BEMD to remove noise, and the residual image analyzed with the Sobel edge detector for crack detection. The results are compared with results from the Canny edge detector, which uses a Gaussian filter for image smoothing before performing edge detection. The objective is to qualitatively explore how well BEMD is able to smooth an image for more effective and speedier edge detection with the Sobel method.

  15. Evaluating Pavement Cracks with Bidimensional Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Nii Attoh-Okine

    2008-05-01

    Full Text Available Crack evaluation is essential for effective classification of pavement cracks. Digital images of pavement cracks have been analyzed using techniques such as fuzzy set theory and neural networks. Bidimensional empirical mode decomposition (BEMD, a new image analysis method recently developed, can potentially be used for pavement crack evaluation. BEMD is an extension of the empirical mode decomposition (EMD, which can decompose nonlinear and nonstationary signals into basis functions called intrinsic mode functions (IMFs. IMFs are monocomponent functions that have well-defined instantaneous frequencies. EMD is a sifting process that is nonparametric and data driven; it does not depend on an a priori basis set. It is able to remove noise from signals without complicated convolution processes. BEMD decomposes an image into two-dimensional IMFs. The present paper explores pavement crack detection using BEMD together with the Sobel edge detector. A number of images are filtered with BEMD to remove noise, and the residual image analyzed with the Sobel edge detector for crack detection. The results are compared with results from the Canny edge detector, which uses a Gaussian filter for image smoothing before performing edge detection. The objective is to qualitatively explore how well BEMD is able to smooth an image for more effective edge detection with the Sobel method.

  16. DEVELOPMENT OF A HYDROPHOBIC SUBSTANCE TO MITIGATE PAVEMENT ICE ADHESION

    Science.gov (United States)

    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...

  17. A Detailed Study of Cbr Method for Flexible Pavement Design

    Directory of Open Access Journals (Sweden)

    Er. Devendra Kumar Choudhary

    2014-06-01

    Full Text Available As per IRC recommendation, California Bearing Ratio (CBR value of subgrade is used for design of flexible pavements. California Bearing Ratio (CBR value is an important soil parameter for design of flexible pavements and runway of air fields. It can also be used for determination of sub grade reaction of soil by using correlation. It is one of the most important engineering properties of soil for design of sub grade of roads. CBR value of soil may depends on many factors like maximum dry density (MDD, optimum moisture content (OMC, liquid limit (LL, plastic limit (PL, plasticity index (PI, type of soil, permeability of soil etc. Besides, soaked or unsoaked condition of soil also affects the value. These tests can easily be performed in the laboratory. the estimation of the CBR could be done on the basis of these tests which are quick to perform, less time consuming and cheap, then it will be easy to get the information about the strength of subgrade over the length of roads, By considering this aspect, a number of investigators in the past made their investigations in this field and designed different pavements by determining the CBR value on the basis of results of low cost, less time consuming and easy to perform tests. In this study, attempts have been made to seek the values of CBR of different soil samples and correlate their CBR values for the design purpose of flexible pavement as per guidelines of IRC: SP: 37-2001.

  18. Nitrogen Transformations in Three Types of Permeable Pavement

    Science.gov (United States)

    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...

  19. Modeling Recycling Asphalt Pavement Processing Technologies in Asphalt Mixing Plants

    Directory of Open Access Journals (Sweden)

    Simonas Tamali?nas

    2011-04-01

    Full Text Available The article presents reclaimed asphalt pavement (RAP processing technologies and equipment models used in the asphalt mixing plant (AMP. The schematic model indicating all possible ways to process RAP in AMP is shown. The model calculating the needed temperature of mineral materials used for heating RAP is given and an example of such calculation is provided.Article in Lithuanian

  20. Mechanistic modelling of weak interlayers in flexible and semi-flexible road pavements: Part 2

    Directory of Open Access Journals (Sweden)

    M de Beer

    2012-04-01

    Full Text Available This paper (Part 2 of a two-part set of papers discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are available to detect and investigate the existence of these weak layers in cemented pavement layers. In Part 2, several cases of the above conditions for different road pavement types are discussed, with field examples. Mechanistic analyses were done on a typical hot mix asphalt (HMA, several cases of a cemented base pavement and a granular base pavement, with and without these weak layers and interface conditions to demonstrate their adverse effects. The analyses focus on the strain energy of distortion (SED as a pavement response parameter to indicate the potential for structural damage expected within the pavement structure or layer. Generally, the higher the SED, the higher the potential damage in the pavement layer. SED shows some potential for quantifying the relative effects of these weak layers, interlayers, laminations and/or weak interfaces within flexible and semi-flexible pavements.

  1. Mechanistic modelling of weak interlayers in flexible and semi-flexible road pavements: Part 2

    Scientific Electronic Library Online (English)

    M, de Beer; J W, Maina; F, Netterberg.

    2012-04-01

    Full Text Available This paper (Part 2 of a two-part set of papers) discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for [...] pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are available to detect and investigate the existence of these weak layers in cemented pavement layers. In Part 2, several cases of the above conditions for different road pavement types are discussed, with field examples. Mechanistic analyses were done on a typical hot mix asphalt (HMA), several cases of a cemented base pavement and a granular base pavement, with and without these weak layers and interface conditions to demonstrate their adverse effects. The analyses focus on the strain energy of distortion (SED) as a pavement response parameter to indicate the potential for structural damage expected within the pavement structure or layer. Generally, the higher the SED, the higher the potential damage in the pavement layer. SED shows some potential for quantifying the relative effects of these weak layers, interlayers, laminations and/or weak interfaces within flexible and semi-flexible pavements.

  2. Coal-tar based pavement sealant toxicity to freshwater macroinvertebrates

    International Nuclear Information System (INIS)

    Non-point-source pollution is a major source of ecological impairment in urban stream systems. Recent work suggests that coal-tar pavement sealants, used extensively to protect parking areas, may be contributing a large portion of the polycyclic aromatic hydrocarbon (PAH) loading seen in urban stream sediments. The hypothesis that dried coal-tar pavement sealant flake could alter the macroinvertebrate communities native to streams in Austin, TX was tested using a controlled outdoor laboratory type approach. The treatment groups were: control, low, medium, and high with total PAH concentrations (TPAH = sum of 16 EPA priority pollutant PAHs) of 0.1, 7.5, 18.4, and 300 mg/kg respectively. The low, medium, and high treatments were created via the addition of dried coal-tar pavement sealant to a sterile soil. At the start of the 24-day exposure, sediment from a minimally impacted local reference site containing a community of live sediment-dwelling benthic macroinvertebrates was added to each replicate. An exposure-dependent response was found for several stream health measures and for several individual taxa. There were community differences in abundance (P = 0.0004) and richness (P < 0.0001) between treatments in addition to specific taxa responses, displaying a clear negative relationship with the amount of coal-tar sealant flake. These results support the hypothesis that coal-tar pavement sealants contain bioavailable PAHs that may harm aquatic environments. - Coal-tar may harm aquatic environments. - Coal-tar pavement sealants degrade stream invertebrate communities.

  3. Acute respiratory distress syndrome and pneumothorax

    OpenAIRE

    Terzi, Eirini; Zarogoulidis, Konstantinos; Kougioumtzi, Ioanna; Dryllis, Georgios; Kioumis, Ioannis; Pitsiou, Georgia; Machairiotis, Nikolaos; Katsikogiannis, Nikolaos; LAMPAKI, SOFIA; Papaiwannou, Antonis; Tsiouda, Theodora; Madesis, Athanasios; Karaiskos, Theodoros; Zaric, Bojan; Branislav, Perin

    2014-01-01

    Acute respiratory distress syndrome (ARDS) can occur during the treatment of several diseases and in several interventional procedures as a complication. It is a difficult situation to handle and special care should be applied to the patients. Mechanical ventilation is used for these patients and several parameters are changed constantly until compliance is achieved. However, a complication that is observed during the application of positive airway pressure is pneumothorax. In our current wor...

  4. Acute Respiratory Distress Syndrome: A Historical Perspective

    OpenAIRE

    Bernard, Gordon R

    2005-01-01

    Though well described even in ancient writings, the acute respiratory distress syndrome (ARDS) gained major medical attention with the availability of mechanical ventilation and establishment of intensive care units. In the 50 years since this beginning there have been remarkable advances in the understanding of the etiology, physiology, histology, and epidemiology of this often lethal complication of common human maladies. Until recently, improvements in outcome have mainly followed improvem...

  5. Update in acute respiratory distress syndrome

    OpenAIRE

    Koh, Younsuck

    2014-01-01

    Acute respiratory distress syndrome (ARDS) is characterized by permeability pulmonary edema and refractory hypoxemia. Recently, the new definition of ARDS has been published, and this definition suggested severity-oriented respiratory treatment by introducing three levels of severity according to PaO2/FiO2 and positive end-expiratory pressure. Lung-protective ventilation is still the key of better outcome in ARDS. Through randomized trials, short-term use of neuromuscular blockade at initial ...

  6. An Unusual Cause of Recurrent Respiratory Distress

    OpenAIRE

    Joshi Neha

    2010-01-01

    A one and a half years old boy presented with recurrent episodes of respiratory distress, accompanied by dry non spasmodic cough and characterized by appearance of a continuous stridor showing no positional variation. The child was symptomatic since early infancy. Parents also complained of inability to gain weight as compared to other siblings.  There was no history of foreign body ingestion or complaints of asthma or tuberculosis in the family. General physical examination revealed tachypne...

  7. Substance Use, Distress, and Adolescent School Networks

    OpenAIRE

    McLeod, Jane D.; Uemura, Ryotaro

    2012-01-01

    This study examined the associations of substance use, psychological distress, and mental health services receipt with the structure and content of adolescent school-based networks. Using data from the National Longitudinal Study of Adolescent Health, we found that substance use was associated with receiving more, but making fewer, peer nominations. It also was associated with less favorable network characteristics, such as low GPA. Services receipt was associated with receiving and making fe...

  8. System influences on posthomicide beliefs and distress.

    Science.gov (United States)

    Thompson, M P; Norris, F H; Ruback, R B

    1996-12-01

    Criminal justice system experiences in 150 family members of homicide victims were investigated. The study had two goals: (a) to document the experiences of homicide survivors in the criminal justice system, including case outcomes, criminal justice system activities, and satisfaction with system personnel; and (b) to determine if experiences with the police impacted posthomicide beliefs (cognitive assumptions about the world and one's relationship to it) and psychological distress. The sample, which was identified through the Medical Examiner's Office, was drawn from all criminal homicides from 1.5 to 5 years prior to selection. Results showed that family members of homicide victims were very dissatisfied with their experiences in the criminal justice system. Additionally, whereas objective system outcomes (e.g., arrest) did not directly affect posthomicide beliefs and distress, subjective system outcomes (e.g., police satisfaction) directly affected beliefs and indirectly affected distress. There was some support for both equity theory and a cognitive theory of change, the two theories that guided the model specification. PMID:9194330

  9. Psychosocial distress and periodontitis in adolescents

    DEFF Research Database (Denmark)

    Lopez, Rodrigo; Ramírez, Valeria

    2012-01-01

    Periodontitis is an inflammatory disease associated with predominantly gram negative biofilms and characterized by the progressive destruction of the supporting tissues of the teeth. Some studies conducted among adults have found a significant association between periodontitis and dimensions of psychosocial distress and it is unclear whether this association can be found among younger subjects in which destruction of periodontal tissues as a result of periodontitis are less severe. Purpose: The main aim of this study was to assess whether adolescents with periodontitis presented with higher scores for non-psychotic psychosocial disorders than control subjects without periodontitis. Materials and Methods: We used a case control study (n=160) nested in a well-defined adolescent population (n=9,163) and the 28-item Spanish version of the General Health Questionnaire. The inclusion criterion for being a case was clinical attachment level ? 3 mm in at least two teeth. Multiple logistic regression analyses were used to assess the association between periodontitis and psychosocial distress. Results: The response rate was high and 94% of the participants answered all the items of the questionnaire. Similarly, the internal consistency of the instrument was high (Cronbach’s ? = 0.91). The results of multiple logistic regression analyses, adjusted for age and gender, suggested an association between case status and higher total scoring for psychosocial distress (OR=1.69). Among the four subdomains of General Health Questionnaire, the dimensions ‘somatic symptoms’ and ‘severe depression’ appeared positively associated with periodontal case status though not significantly.

  10. Neural circuits underlying emotional distress in humans.

    Science.gov (United States)

    Sinha, Rajita; Lacadie, Cheryl; Skudlarski, Pawel; Wexler, Bruce E

    2004-12-01

    Difficulties in the experiences and regulation of emotional stress have been associated with the development of psychiatric and substance use disorders. This study examined neural circuits underlying emotional distress in healthy volunteers using functional magnetic resonance imaging (fMRI) techniques. Recall of personal nontraumatic, highly stressful life events with script-driven guided imagery was used to induce moderate levels of emotional distress in eight healthy volunteers. Subjects participated in six guided imagery trials (3 separate stress and 3 separate neutral-relaxing scripts each) interspersed by rest periods in a 1.5T scanner. Results indicated significant activation in the medial prefrontal, anterior cingulate, caudate, putamen, thalamus, hippocampus, parahippocampal gyrus, and posterior cingulate regions during emotional distress relative to brain activation during neutral-relaxing imagery. These findings suggest that specific striatal-limbic-prefrontal cortical circuits are involved in the experience and regulation of emotional stress in humans. The study also provides a feasible method to study brain correlates of emotional stress processing in healthy individuals and clinical samples. PMID:15677422

  11. Research on the characteristics of temperature field of asphalt pavement in seasonal frozen region

    Science.gov (United States)

    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.

  12. Characterising the Deformation Behaviour of Unbound Granular Materials in Pavement Structures

    OpenAIRE

    Rahman, Mohammad Shafiqur

    2015-01-01

    Unbound granular materials (UGMs) used in the base and sub-base layers of flexible pavements play a significant role in the overall performance of the structure. Proper understanding and characterization of the deformation behaviour of UGMs in pavement structures are, therefore, vital for the design and maintenance of flexible pavements. In this study, the resilient deformation (RD) and the permanent deformation (PD) behaviour of UGMs were investigated for the better understanding and improve...

  13. Socio-economic aspects of the Byzantine mosaic pavements of Phoenicia and northern Palestine

    OpenAIRE

    Merrony, Mark W.; Dr Claudine Dauphin, Dr Julian Raby

    2002-01-01

    ?The present thesis analyzes the Byzantine mosaic pavements of Phoenicia and Northern Palcatine from a socio-economic perspective, primarily by examining the laying of pavements including technical aspects and bedding, the quality of decoration, the distribution of pavements in time and space, as well as inscriptions which provide names of donors and artists as well as dates. The approach adopted represents a novel alternative and complement to typical interpretations of mosaic floor decora...

  14. Evaluation of the Structure-induced Rolling Resistance (SRR) for pavements including viscoelastic material layers

    OpenAIRE

    Chupin, Olivier; Piau, Jean Michel; Chabot, Armelle

    2013-01-01

    This article addresses the question of whether the viscoelastic behavior of asphalt pavements, as part of the factors that impact the rolling resistance, might lead to substantially higher energy consumption of road traffic, as compared to non-dissipative pavements. In the context of sustainable development (fuel consumption, gas emission), this is a current issue for the pavement design community. This problem is tackled by a theoretical approach which consists in computing the Structure-ind...

  15. Effects of thermal properties on temperature and moisture profiles and the performance of PCC pavements

    OpenAIRE

    Upender Kodide M.S.; Alex Hak-Chul Shin

    2011-01-01

    To understand the effects of thermal properties on temperature and the moisture profile in Portland cement concrete (PCC) pavements, an Enhanced Integrated Climatic Model (EICM) analysis was performed for a typical PCC pavement section in Louisiana. The EICM analysis showed that the temperature in the middle layer of PCC pavement decreased as thermal conductivity increased, and the temperature remained constant for higher thermal conductivity values. Temperature was measured at several depths...

  16. Functionality Enhancement of Industrialized Optical Fiber Sensors and System Developed for Full-Scale Pavement Monitoring

    OpenAIRE

    Huaping Wang; Wanqiu Liu; Jianping He; Xiaoying Xing; Dandan Cao; Xipeng Gao; Xiaowei Hao; Hongwei Cheng; Zhi Zhou

    2014-01-01

    Pavements always play a predominant role in transportation. Health monitoring of pavements is becoming more and more significant, as frequently suffering from cracks, rutting, and slippage renders them prematurely out of service. Effective and reliable sensing elements are thus in high demand to make prognosis on the mechanical properties and occurrence of damage to pavements. Therefore, in this paper, various types of functionality enhancement of industrialized optical fiber sensors for pav...

  17. The influence of construction quality control data variability on pavements evolution

    OpenAIRE

    Freitas, Elisabete F.; Pereira, Paulo A. A.; Santos, Lui?s Picado

    2005-01-01

    Predicting pavement evolution is a fundamental component in pavement maintenance and rehabilitation management work. However, it is very complex to carry out due to several drawbacks, namely a common use of inadequate quality control procedures or a lack of reproducibility of quality control data. This paper describes the main conclusions of a study on the influence of construction quality control data on pavement evolution. It was possible to develop a methodology for this purpose based on s...

  18. Assessment of Distress Associated to Psychopathology in Children and Adolescents

    Directory of Open Access Journals (Sweden)

    Wendy Reich

    2009-04-01

    Full Text Available The aim of this paper was to study the distress associated to psychopathology in children and adolescents. The sample included 330 children aged 8 to 17 years attending outpatient mental health services of the public network in Barcelona(Spain assessed using a structured diagnostic interview. A substantial part of children brought to treatment suffered distress associated to internalizing and externalizing psychological symptoms. Psychological distress was most frequent among girls and among adolescents, and was more frequently reported by children and adolescents than by their parents. It was also a marker of perception of need of psychological help, and it was significantly related to diagnosis, subthreshold conditions and functional impairment. Individual symptoms of depression, dysthymia, generalized anxiety disorder and oppositional defiant disorder were most associated with psychological distress. Given the potential importance of subjective distress as well as impairment for the identification and definition of psychopathology and planning of treatment, diagnostic assessment should include questions related to distress.

  19. A demedicalized view of maternal distress: conceptualization and instrument development.

    Science.gov (United States)

    Arditti, Joyce A; Grzywacz, Jospeh G; Gallimore, Sara Wang

    2013-11-01

    The goal of this article was to describe instrument development of a demedicalized, multidomain view of maternal distress, with psychological, relational, and situational manifestations. We developed a pilot instrument derived from our previous grounded theory conceptualization of maternal distress and administered it to a purposive sample of 100 low-income single mothers. Analyses testing the relationship between maternal distress and depressive symptoms, guilt, child rearing stress, and community needs variables suggested that the maternal distress inventory had convergent, discriminant, and concurrent validity. Not only was maternal distress distinct from depressive symptomology and generalized child rearing stress, it appeared to be more meaningfully associated with "real world" outcomes of interest to psychological service providers than purely psychological measures of the distress. PMID:22984879

  20. Psychological and physical distress of cancer patients during radiotherapy

    CERN Document Server

    König, A

    2001-01-01

    Purpose: patients undergoing radiotherapy have physical and psychological symptoms related to the underlying disease and the treatment. In order to give the best possible support to the patients, more knowledge about the amount and the changing of distress in the course of radiotherapy is of essentially importance. Methods: The distress was measured in a consecutive sample of cancer patients (n=82) undergoing radiotherapy. Each patient was given the EORTC-QLQ-C30, the HADS and a special questionnaire which ascertain radiotherapy-specific items before starting the radiotherapy, at the onset of radiotherapy, in the third week of radiotherapy and 3 weeks after the end of radiotherapy. Results: within the first week of treatment the psychological distress of the patients is increasing; 98.8 % of the patients are 'moderate distressed', 46 % 'severe distressed'. General physical symptoms seem not to be affected by the radiotherapy, there is no changing. The distress caused by the organization of the radiotherapy is...

  1. Financial Distress Prediction in Emerging Market: Empirical Evidences from Iran

    Directory of Open Access Journals (Sweden)

    Mahdi Salehi

    2009-08-01

    Full Text Available In this article the ability of financial ratios for prediction of financial distress of the listed companies in Tehran Stock Exchange (TES was investigated. For this reason, the multiple regression models were used and a model was presented for prediction of financial distress in listed companies in TES. The assessment of the model was done by utilizing the data of two groups. The first group contained 30 companies which don't have any financial distress, and the second group, similarly, contained 30 companies which have financial distress. The presented model was according to five the ratios, namely; ratios indicate liquidity, profitability, managing of debt and managing of property. The statistical results of the model indicate the validity of that model and the selected ratios. The results of the test of the ability of model prediction indicate the reality that the model designed four years before financial distress in companies; present a correct prediction about the financial distress.

  2. Performance of pervious pavement parking bays storing rainwater in the north of Spain.

    Science.gov (United States)

    Gomez-Ullate, E; Bayon, J R; Coupe, S; Castro-Fresno, D

    2010-01-01

    Pervious pavements are drainage techniques that improve urban water management in a sustainable manner. An experimental pervious pavement parking area has been constructed in the north of Spain (Santander), with the aim of harvesting good quality rainwater. Forty-five pervious pavement structures have been designed and constructed to measure stored water quantity and quality simultaneously. Ten of these structures are specifically constructed with different geotextile layers for improving water storage within the pavements. Following the confirmation in previous laboratory experiments that the geotextile influenced on water storage, two different geosynthetics (Inbitex and a One Way evaporation control membrane) and control pervious pavements with no geotextile layers were tested in the field. Weather conditions were monitored in order to find correlations with the water storage within the pervious pavement models tested. During one year of monitoring the three different pervious pavement types tested remained at their maximum storage capacity. The heavy rain events which occurred during the experimental period caused evaporation rates within the pervious pavements to be not significant, but allowed the researchers to observe certain trends in the water storage. Temperature was the most closely correlated weather factor with the level of the water stored within the pervious pavements tested. PMID:20706008

  3. Assessment of Distress Associated to Psychopathology in Children and Adolescents

    OpenAIRE

    Wendy Reich; Lourdes Ezpeleta; Roser Granero

    2009-01-01

    The aim of this paper was to study the distress associated to psychopathology in children and adolescents. The sample included 330 children aged 8 to 17 years attending outpatient mental health services of the public network in Barcelona(Spain) assessed using a structured diagnostic interview. A substantial part of children brought to treatment suffered distress associated to internalizing and externalizing psychological symptoms. Psychological distress was most frequent among girls and among...

  4. Distress, anxiety, and depression in cancer patients undergoing chemotherapy

    OpenAIRE

    Thomas Bejoy C; Devi Nandkumar; Sarita Gangadharan P; Pandey Manoj; Hussain Badridien M; Krishnan Rita

    2006-01-01

    Abstract Background Chemotherapy for cancer is an intense and cyclic treatment associated with number of side-effects. The present study evaluated the effect of chemotherapy on distress, anxiety and depression. Patients and methods A total of 117 patients were evaluated by using distress inventory for cancer (DIC2) and hospital anxiety and depression scale (HADS). Majority of the patients were taking chemotherapy for solid tumors (52; 44.4%). Results The mean distress score was 24, 18 (15.38%...

  5. Psychological distress in morbid obesity in relation to weight history

    OpenAIRE

    Petroni, Maria Letizia; Villanova, Nicola; Avagnina, Sebastiano; Fusco, Maria Antonia; Fatati, Giuseppe; Compare, Angelo; Marchesini, Giulio

    2007-01-01

    Background: Very few data are available on psychological distress in morbidly obese subjects in relation to the history of their weight. In subjects with childhood obesity, psychological distress might be better than in adult-onset obesity, because of progressive adaptation to the social stigma. Methods: Psychological distress was tested in relation to BMI at age 20 years (BMI-20), weight history and somatic co-morbidities in 632 treatment-seeking, morbidly obese participants from the QUOV...

  6. Financial Distress Prediction in Emerging Market: Empirical Evidences from Iran

    OpenAIRE

    Mahdi Salehi; Bizhan Abedini

    2009-01-01

    In this article the ability of financial ratios for prediction of financial distress of the listed companies in Tehran Stock Exchange (TES) was investigated. For this reason, the multiple regression models were used and a model was presented for prediction of financial distress in listed companies in TES. The assessment of the model was done by utilizing the data of two groups. The first group contained 30 companies which don't have any financial distress, and the second group, similarly, con...

  7. The impact of light-colored pavements on active layer dynamics revealed by Ground-Penetrating Radar monitoring

    OpenAIRE

    Jørgensen, Anders Stuhr; Ingeman-nielsen, Thomas

    2008-01-01

    Ground-penetrating radar (GPR) has been used to study the variations in the depth of the frost table throughout a complete thaw-freeze season in Kangerlussuaq Airport, western Greenland. In autumn 2000, three test areas were painted white on the parking area of the airport in order to reduce further development of depressions in the asphalt pavement. One of these areas has been used in the GPR investigations to compare the variations of the frost table underneath a normal dark asphalt surface...

  8. The Effects of Desert Pavements (Gravel Mulch) on Soil Micro-Hydrology

    Science.gov (United States)

    Kaseke, K. F.; Mills, A. J.; Henschel, J.; Seely, M. K.; Esler, K.; Brown, R.

    2012-05-01

    The effect of desert pavements (gravel mulch) on near surface soil micro-hydrology has been inadequately studied. Micro-hydrology in arid ecosystems occurs due to a daily non rainfall atmospheric water cycle, consisting of an input phase (dew, fog, vapour adsorption) and an evaporation phase. A winter comparative study between a bare soil (control) and gravel mulch using the automated microlysimeter approach was conducted in Stellenbosch, South Africa in 2008. Results showed that dew deposition and direct water vapour adsorption were significantly higher into bare soil compared to gravel mulch. In contrast, however, soil moisture from rain persists for a longer time under gravel mulch compared to bare soil. This result suggests that the greatest impact of gravel mulch on soil micro-hydrology is towards conserving moisture and could explain why the treatment is used in dry-land agriculture in Mediterranean regions.

  9. Desert pavement development on the lake shorelines of Lake Eyre (South), South Australia

    Science.gov (United States)

    Al-Farraj, Asma

    2008-08-01

    To the southwest of Lake Eyre (South), South Australia, silcrete boulders exposed by the erosion of the surrounding fine sediments undergo mechanical weathering to form desert pavement. Successive palaeoshorelines of Lake Eyre have exposed an age-related sequence of different stages in the weathering of the boulders. This study investigates desert pavement development in this saline environment. In addition, it attempts to develop a model for the development of desert pavement following exposure of the silcrete boulders, based on palaeo-lake shorelines dated from previous studies. Seven stages can be recognised corresponding to stages of soil and pavement development. Prior to stage one is the actual exposure of the boulder as the result of erosion by wave action at the lake shoreline or by erosion as the lake level falls during desiccation. At stage-1 the upper surface of the boulder breaks up through mechanical weathering (salt weathering), while the rest of the boulder is still buried. At stage-2 the surface fragments fall to the edge of the stone and expose more of the stone, which continues to break-up. There is no soil development in stages 1 and 2. By stage-3 most of the stone is exposed and broken up, making a mini-hill. At this stage soil development begins with the accumulation of sandy soil between the rock fragments. At stage-4 the stones form small cones and the soil is more developed. It is sandy with a typical of colour 10 YR 6/6. At stage-5 the stones forming the small cone are completely fragmented. Stone fragments at the centre are very angular but smoother at the edges of the mini-hill as the result of weathering (etching by chemical processes?). Soil texture is silty/sand and soil colour is 7.5 YR 6/6. At stage-6 the surface is nearly flat. The soil is sandy/silt and soil colour is between 7.5 YR 5/6 and 7.5 YR 5/8. Stage-7a is the gibber plain phase, composed of small well rounded stones, as a result of continued etching of the edges of the fragmented stones. The soil is silty, and the soil colour is between 5 YR 5/6 and 5 YR 5/8. Stage-7b is also gibber plain, with small well rounded stone fragments but where the soil has been replaced by crystalline gypsum. This sequence differs from sequences described in other areas, especially on alluvial fan or terrace surfaces. This may be partly due to the different origin of the clasts, as "pre-weathered" silcrete boulders, and partly due to the importance of chemical weathering by "etching" in this salt-rich environment.

  10. In-situ determination of moisture in road pavement by nuclear methods

    International Nuclear Information System (INIS)

    The use of neutron moisture probes to determine moisture in compacted pavement layers has been studied on samples representative of those used by the New South Wales Department of Main Roads for roadway construction. The aim of this work was to measure the average moisture content of the upper layer (15-20 cm thick) with minimum interference from moisture in underlying layers. Sub-surface probes using high (?-Be) and low (?-Li) energy neutron sources were examined; conventional ?-Be sources in specially designed compact probes should result in an error due to base moisture and density variations of less than 0.4 wt % moisture. As this error is probably less than those due to sampling and geometry variations in the field, such a probe should be sufficiently accurate for DMR requirements. If less sensitivity to base moisture is required, the ?-Li source will reduce this sensitivity by a factor of about 1.4

  11. Accuracy of the Danish version of the 'distress thermometer'

    DEFF Research Database (Denmark)

    Bidstrup, Pernille Envold; Mertz, Birgitte Goldschmidt

    2012-01-01

    Objective: Short screening instruments have been suggested to improve the detection of psychological symptoms. We examined the accuracy of the Danish version of the 'Distress Thermometer'. Methods: Between October 2008 and October 2009, 426 women with newly diagnosed primary breast cancer who were operated at the Breast Surgery Clinic of the Rigshospitalet, Copenhagen, were eligible for this study. Of these, 357 participated (84%) and 333 completed a questionnaire. The distress thermometer was evaluated against the 'hospital anxiety and depression scale' (HADS). We also examined the women's wish for referral for psychological support. Results: A cut-off score of 6 vs 7 (low:?6, high:?7) on the distress thermometer was optimal for confirming distress, with a sensitivity of 42%, a specificity of 93%, a positive predictive value (PPV) of 78% and a negative predictive value (NPV) of 73%. A cut-off score of 2 vs 3 was optimal for screening, with a sensitivity of 99%, a specificity of 36%, a PPV of 47% and a NPV of99%. Of those who were distressed using the cut-off score of 2 vs 3 on the distress thermometer, 17% (n = 41) wished to be referred for psychological support and 57% (n = 140) potentially wanted a later referral. Conclusion: The distress thermometer performed satisfactorily relative to the HADS in detecting distress in our study. A screening procedure in which application of the distress thermometer is a first step could be useful for identifying persons in need of support. Copyright © 2011 John Wiley & Sons, Ltd.

  12. Development of a distress inventory for cancer: preliminary results.

    Directory of Open Access Journals (Sweden)

    Thomas B

    2002-01-01

    Full Text Available CONTEXT: Advances in cancer treatment have led to cure and prolongation of patients? lives; however associated psychosocial problems, including distress, can detrimentally affect patients? compliance with treatment and ultimately, their outcome. Symptom distress has been well addressed in many studies; however, psychological distress has only been quantified by using depression or anxiety scales/checklists or quality of life scales containing a distress sub scale/component or by the use of scales that are not psychological distress-specific. AIMS: The present study is an attempt to construct a psychological distress inventory for specific use with cancer patients. SETTINGS AND DESIGN: The standardisation sample consisted of 63 randomly selected patients with head and neck cancer who had undergone/ were undergoing curative treatment at the Regional Cancer Centre, Trivandrum. PATIENTS AND METHODS: The Distress Inventory for Cancer contained 57 positively and negatively toned items. An item analysis was conducted, followed by a factor analysis, thereby identifying the domains influencing distress. RESULTS: The final questionnaire contained 26 items subdivided into four domains viz. the personal, spiritual, physical, and the family domains, with each domain providing a sub score. The reliability coefficient (Cronbach?s alpha of the scale was found to be 0.85. CONCLUSIONS: These are the preliminary results of an ongoing study on global distress and tool development process. Reported here is the first step towards development of such tool.

  13. Reduction in mental distress among substance users receiving inpatient treatment

    Directory of Open Access Journals (Sweden)

    Friborg Oddgeir

    2010-12-01

    Full Text Available Abstract Background Substance users being admitted to inpatient treatment experience a high level of mental distress. In this study we explored changes in mental distress during treatment. Methods Mental distress, as measured by the HSCL-10, was registered at admission and at discharge among 164 substance users in inpatient treatment in Northern Norway. Predictors of reduction in mental distress were examined utilizing hierarchical regression analysis. Results We found a significant reduction in mental distress in the sample, but the number of patients scoring above cut-off on the HSCL-10 at discharge was still much higher than in the general population. A more severe use of substances as measured by the AUDIT and the DUDIT, and being female, predicted a higher level of mental distress at admission to treatment as well as greater reduction in mental distress during treatment. Holding no education beyond 10 year compulsory school only predicted a reduction in mental distress. Conclusions The toxic and withdrawal effects of substances, level of education as well as gender, contributed to the differences in change in mental distress during treatment. Regression to the mean may in part explain some of the findings.

  14. Permeability measurement and scan imaging to assess clogging of pervious concrete pavements in parking lots.

    Science.gov (United States)

    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 30°C 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

  15. Protein permeability in the adult respiratory distress syndrome. Loss of size selectivity of the alveolar epithelium.

    OpenAIRE

    Holter, J. F.; Weiland, J. E.; Pacht, E. R.; Gadek, J. E.; Davis, W. B.

    1986-01-01

    Small amounts of plasma protein normally reach the alveolar epithelial surface by a size-selective process that restricts the passage of very large molecules. Size selectivity may be compromised in the lungs of patients with the adult respiratory distress syndrome (ARDS). To assess this question, bronchoalveolar lavage fluid (BALF) from normal volunteers (n = 11), cardiac edema patients (n = 3), and ARDS patients (n = 8) was compared. Mean total protein in ARDS BALF was greater than 12 times ...

  16. Design Methodologies of Asphalt Pavement Used in China and Mozambique

    Directory of Open Access Journals (Sweden)

    Jose Francisco Rufino Diogo

    2007-01-01

    Full Text Available 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.

  17. Full scale demonstration of air-purifying pavement.

    Science.gov (United States)

    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

  18. Making the Grade but Feeling Distressed: Gender Differences in Academic Performance and Internal Distress.

    Science.gov (United States)

    Pomerantz, Eva M.; Altermatt, Ellen Rydell; Saxon, Jill L.

    2002-01-01

    There is disagreement over whether girls or boys are at risk in the context of school. Girls outperform boys in school, particularly in stereotypically feminine subjects. However, girls are also more vulnerable to internal distress than boys are. The aim of this research was to understand this pattern of gender differences. (Author)

  19. Acute respiratory distress syndrome and pneumothorax.

    Science.gov (United States)

    Terzi, Eirini; Zarogoulidis, Konstantinos; Kougioumtzi, Ioanna; Dryllis, Georgios; Kioumis, Ioannis; Pitsiou, Georgia; Machairiotis, Nikolaos; Katsikogiannis, Nikolaos; Lampaki, Sofia; Papaiwannou, Antonis; Tsiouda, Theodora; Madesis, Athanasios; Karaiskos, Theodoros; Zaric, Bojan; Branislav, Perin; Zarogoulidis, Paul

    2014-10-01

    Acute respiratory distress syndrome (ARDS) can occur during the treatment of several diseases and in several interventional procedures as a complication. It is a difficult situation to handle and special care should be applied to the patients. Mechanical ventilation is used for these patients and several parameters are changed constantly until compliance is achieved. However, a complication that is observed during the application of positive airway pressure is pneumothorax. In our current work we will present definition and causes of pneumothorax in the setting of intensive care unit (ICU). We will identify differences and similarities of this situation and present treatment options. PMID:25337400

  20. Acute respiratory distress caused by Neosartorya udagawae

    Directory of Open Access Journals (Sweden)

    John J. Farrell

    2014-10-01

    Full Text Available We describe the first reported case of acute respiratory distress syndrome (ARDS attributed to Neosartorya udagawae infection. This mold grew rapidly in cultures of multiple respiratory specimens from a previously healthy 43-year-old woman. Neosartorya spp. are a recently recognized cause of invasive disease in immunocompromised patients that can be mistaken for their sexual teleomorph, Aspergillus fumigatus. Because the cultures were sterile, phenotypic identification was not possible. DNA sequencing of ITS, calmodulin and ?-tubulin genes supported identification of Neosartorya udagawae. Our case is the first report of ARDS associated with Neosartorya sp. infection and defines a new clinical entity.

  1. Adult respiratory distress syndrome: CT findings

    International Nuclear Information System (INIS)

    Adult respiratory distress syndrome (ARDS) is associated with a mortality in excess of 50%. The authors performed CT examinations on 26 patients with ARDS. The test was needed to rule out intra-abdominal abscesses, empyemas, or additional pathology not imaged on chest radiographs. The pattern of lung disease was analyzed according to distribution. Diffuse consolidation, multifocal patch involvement, and lobar or segmental disease were detected. Over half of the patients developed cystic lung spaces. Pleural effusions, pneumothoraces, and unexpected abscesses and empyemas were discovered. The authors conclude that CT in ARDS can disclose additional complications not visible on bedside chest radiographs, thus improving the management of selected patients

  2. Surfactant treatment for acute respiratory distress syndrome

    OpenAIRE

    Lopez-herce, J.; Lucas, N.; Carrillo, A.; Bustinza, A.; Moral, R.

    1999-01-01

    OBJECTIVE—To determine prospectively the efficacy of surfactant in acute respiratory distress syndrome.?STUDY DESIGN—Twenty patients, 1 month to 16 years of age, diagnosed with an acute pulmonary disease with severe hypoxaemia (PaO2/FiO2 < 100) (13 with systemic or pulmonary disease and seven with cardiac disease) were treated with one to six doses of 50-200 mg/kg of porcine surfactant administered directly into the trachea. The surfactant was considered to be ef...

  3. A Statistical Analysis to Predict Financial Distress

    Directory of Open Access Journals (Sweden)

    Nicolas Emanuel Monti

    2010-09-01

    Full Text Available The aim of this study is to apply the statistical inference to identify if a firm is likely to become financially distressed in the short term. To do this, we decided to collect data from the firms’ financial statements. The analyses performed were based on a group of 45 financial ratios observed from a sample of 86 firms operating in Argentina. First, we used the principal component analysis to turn the information in the 45 original ratios into two new global variables named as ?Risk and ?Return. In this way, we can easily represent and compare in a graph the firms’ risk and return variations. By the computation of these new variables it is possible to quickly financially categorize a certain firm based on the risk the company has with regard to the nature of its business and the risk involved in the amount of debt it has taken in comparison to the profits that were generated during the last two fiscal years. Second, we performed a logistic regression analysis to estimate the probability that a firm becomes financially distressed in the short term. The model finally selected managed to successfully identify 85% of the companies from the sample and it explains 65% of the total sample variability. The model is represented by the following variables: 1 Current Debt Ratio, 2 Total Cost of Debt, 3 Operating Profit Margin, and 4 ?ROE. The outcomes from this study are two tools that were developed based on the statistical inference from which we can quickly asses the financial status of a firm based on its risks and return’s variation as well as to estimate the probability that a firm becomes financially distressed in the short term. There are different ways of taking these tools into practice such as: 1 to control and follow up the financial performance of a company, 2 to support the decision of lending money to a company, 3 to support the decision of investing money or the decision of merging with a company, 4 to support market analysis from a financial perspective, and 5 to support actions or decisions related to the financial assessment of a company that declares itself to be financially distressed.

  4. A Statistical Analysis to Predict Financial Distress

    OpenAIRE

    Nicolas Emanuel Monti; Roberto Mariano Garcia

    2010-01-01

    The aim of this study is to apply the statistical inference to identify if a firm is likely to become financially distressed in the short term. To do this, we decided to collect data from the firms’ financial statements. The analyses performed were based on a group of 45 financial ratios observed from a sample of 86 firms operating in Argentina. First, we used the principal component analysis to turn the information in the 45 original ratios into two new global variables named as ?Risk and ...

  5. Assessment of work intensification by managers and psychological distressed and non-distressed employees : a multilevel comparison

    DEFF Research Database (Denmark)

    Bamberger, Simon Grandjean; Larsen, Anelia

    2015-01-01

    Work intensification is a popular management strategy to increase productivity, but at the possible expense of employee mental stress. This study examines associations between ratings of work intensification and psychological distress, and the level of agreement between compared employee-rated and manager-rated work intensification. Multi-source survey data were collected from 3,064 employees and 573 company managers from the private sector in 2010. Multilevel regression models were used to compare different work intensification ratings across psychological distress strata. Distressed employees rated higher degree of total work intensification compared to non-distressed employees, and on three out of five sub ratings there were an increased prevalence of work intensification in the case group. In general, there was poor agreement between employee and company work intensification rating. Neither manager-rated work intensification nor employee/manager discrepancy in work intensification ratings was associated with psychological distress. Distressed employees had a higher total score of employee/manager agreed work intensification, and a higher prevalence of increased demands of labour productivity. This study demonstrates higher ratings of employee/manager agreed work intensification in distressed employees compared to non-distressed employees, challenging previous findings of reporting bias in distressed employees' assessment of work environment.

  6. DYNAMIC JOINT LOAD TRANSFER EFFICIENCY OF RIGID PAVEMENT

    Directory of Open Access Journals (Sweden)

    YU Xinhua

    2011-02-01

    Full Text Available the mechanistic analysis presented in this paper is only the beginning of new approach for understanding the real joint load transfer capability on airport and highway concrete pavements. It gives up the two major assumptions those have been popularly adopted by hundreds of published papers: the load is transferred under a wheel with zero speed and with fixed position. The real load transfer in field is always under wheels with non-zero speed and with varied position at any moment. The objective of this study focuses on quantifying the dynamic effects of a moving wheel while it is crossing a joint on a pavement. The analysis is conducted using a model of two-slab system on Kelvin foundation under a moving wheel with variable speed v, different pavement damping Cs, foundation reaction modulus k and foundation damping Ck. The dynamic joint load transfer efficiency is temporarily and empirically defined by the peak strain ratio LTE(S on the two sides of a joint. The primary findings include: (1 The higher speed of a moving wheel leads to the higher LTE(S;(2 The larger the pavement damping Cs leads to the higher LTE(S;(3 The numerical ratio c(=LTE(Sdynamic/ LTE(Sstatic varies in the range 1 to 2 mainly depending on speed v and damping Cs;(4 The LTE(Sdynamic is not sensitive to foundation reaction modulus k and foundation damping Ck. Further researches are needed for appropriate applications of the new model in practice.

  7. Performance of waste tyre rubber on model flexible pavement

    OpenAIRE

    D. S. V. Prasad; G. V. R. Prasada Raju

    2009-01-01

    This paper investigates the performance of flexible pavement on expansive soil subgrade using gravel/flyash as subbase course with waste tyre rubber as a reinforcing material. It was observed that from the laboratory test results of direct shear and CBR, the gravel subbase shows better performance as compared to flyash subbase with different percentages of waste tyre rubber as reinforcing material. Cyclic load tests are also carried out in the laboratory by placing a circular metal plate on t...

  8. Pavement Image Segmentation Based on FCM Algorithm Using Neighborhood Information

    OpenAIRE

    Guofeng Qin; Xinsong Wang

    2012-01-01

    Standard FCM algorithm takes the pixel gray-scale information into account only, while ignoring the spatial location of pixels, so the standard FCM algorithm is sensitive to noise. This paper present a pavement image segmentation algorithm based on FCM algorithm using neighborhood information. The presented algorithm introduces neighborhood information into membership function to improve the standard FCM algorithm. It can eliminate noise effectively and retain the boundary information. The ex...

  9. The improvement of pavement performance using asphalt rubber hot mixes

    OpenAIRE

    Pais, Jorge C.; Pereira, Paulo A. A.

    2007-01-01

    The need of a better pavement performance has led researchers to develop new road materials, mainly for the asphalt layers, where the modification of the asphalt is the main example. This modification usually forces the use of polymers and fibers and, more recently, the use of crumb rubber from ground tires, where the modified asphalt is known as asphalt rubber. This asphalt rubber used in asphalt mixtures produces a superior performance if compared to the asphalt mixtures with...

  10. Injuries due to falls as a result of uneven pavements.

    OpenAIRE

    Hunt, M. T.; Chapman, M.; Lloyd, G.

    1991-01-01

    At least one person per day attending the A&E department at King's College Hospital has sustained injuries from uneven pavements. The injuries have a significant morbidity as well as mortality of 1%. A&E records can be a source of useful information to aid local authorities in identifying areas associated with these injuries in order to reduce their frequency and subsequent claims for compensation.

  11. Should we be gritting pavements to prevent pedestrian injuries?

    Science.gov (United States)

    Atenstaedt, Rob; Rees, Michael

    2013-05-01

    Unintentional injuries are an important public health issue, and are a significant burden on health and social services, especially during the winter months. Dr Rob Atenstaedt, Consultant in Public Health Medicine, Public Health Wales & Honorary Senior Lecturer, Bangor University and Professor Michael Rees, University Director of Medical Development & Professor of Cardiovascular Studies, Bangor University look at the importance of pavement gritting in preventing injuries and falls in pedestrians. PMID:23657235

  12. Road Performance of Fiber Reinforced Asphalt Concrete Bridge Deck Pavement

    OpenAIRE

    Xiu Liu; Zhaojie Sun; Decheng Feng; Yixiang Cao

    2013-01-01

    As the problem of asphalt concrete bridge deck pavement is becoming more and more serious, how to improve its road performance has become the focus of the study. Considering fiber is widely used in road engineering, wheel tracking test, flexural test, immersion marshall test and freeze-thaw splitting test were carried out to study road performance of asphalt mixture with different fiber contents, analyzing the function mechanism of fiber reinforced asphalt ...

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

    Science.gov (United States)

    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."

  14. Performance of Recycled Asphalt Pavement as Coarse Aggregate in Concrete

    Directory of Open Access Journals (Sweden)

    Fidelis O. OKAFOR

    2010-12-01

    Full Text Available Recycled asphalt pavement (RAP is the reclaimed and reprocessed pavement material containing asphalt and aggregate. Most RAP is recycled back into pavements, and as a result there is a general lack of data pertaining to the mechanical properties for RAP in other possible applications such as Portland cement concrete. In the present study, some mechanical properties of Portland cement concrete containing RAP as coarse aggregate were investigated in the laboratory. Six concrete mixes of widely differing water/cement ratios and mix proportions were made using RAP as coarse aggregate. The properties tested include the physical properties of the RAP aggregate, the compressive and flexural strengths of the concrete. These properties were compared with those of similar concretes made with natural gravel aggregate. Results of the tests suggest that the strength of concrete made from RAP is dependent on the bond strength of the ?asphalt-mortar? (asphalt binder-sand-filler matrix coatings on the aggregates and may not produce concrete with compressive strength above 25 MPa. However, for middle and low strength concrete, the material was found to compare favorably with natural gravel aggregate.

  15. Full scale demonstration of air-purifying pavement

    International Nuclear Information System (INIS)

    Highlights: ? The results of a demonstration project for photocatalytic pavement are shown. ? The photocatalytic performance was studied in a street as well as on lab scale. ? The outdoor monitoring was performed in different seasons and weather conditions. ? The NOx concentration was in average 19% lowered by the photocatalytic street. ? Under ideal weather conditions the NOx reduction reached up to 45%. -- Abstract: 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 TiO2 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, NO2 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

  16. Numerical Simulation of Moving Load on Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Laj?áková Gabriela

    2015-06-01

    Full Text Available The knowledge of the development with time of the strain and stress states in pavement structures is needed in the solution of various engineering tasks as the design fatigue lifetime reliability maintenance and structure development. The space computing model of the truck TATRA 815 is introduced. The pavement computing model is created in the sense of Kirchhof theory of the thin slab on elastic foundation. The goal of the calculation is to obtain the vertical deflection in the middle of the slab and the time courses of vertical tire forces. The equations of motion are derived in the form of differential equations. The assumption about the shape of the slab deflection area is adopted. The equations of the motion are solved numerically in the environment of program system MATLAB. The dependences following the influence of various parameters (speed of vehicle motion, stiffness of subgrade, slab thickness, road profile on the pavement vertical deflections and the vertical tire forces are introduced. The results obtained from the plate computing model are compared with the results obtained by the FEM analysis. The outputs of the numerical solution in the time domain can be transformed into a frequency domain and subsequently used to solve various engineering tasks.

  17. Reliability-based performance simulation for optimized pavement maintenance

    International Nuclear Information System (INIS)

    Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: ?A novel algorithm using multi-objective particle swarm optimization technique. ? Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. ? A probabilistic model for regression parameters is employed to assess reliability-based performance. ? The proposed approach can help decision makers to optimize roadway maintenance plans.imize roadway maintenance plans.

  18. Reliability-based performance simulation for optimized pavement maintenance

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Jui-Sheng, E-mail: jschou@mail.ntust.edu.tw [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China); Le, Thanh-Son [Department of Construction Engineering, National Taiwan University of Science and Technology (Taiwan Tech), 43 Sec. 4, Keelung Rd., Taipei 106, Taiwan (China)

    2011-10-15

    Roadway pavement maintenance is essential for driver safety and highway infrastructure efficiency. However, regular preventive maintenance and rehabilitation (M and R) activities are extremely costly. Unfortunately, the funds available for the M and R of highway pavement are often given lower priority compared to other national development policies, therefore, available funds must be allocated wisely. Maintenance strategies are typically implemented by optimizing only the cost whilst the reliability of facility performance is neglected. This study proposes a novel algorithm using multi-objective particle swarm optimization (MOPSO) technique to evaluate the cost-reliability tradeoff in a flexible maintenance strategy based on non-dominant solutions. Moreover, a probabilistic model for regression parameters is employed to assess reliability-based performance. A numerical example of a highway pavement project is illustrated to demonstrate the efficacy of the proposed MOPSO algorithms. The analytical results show that the proposed approach can help decision makers to optimize roadway maintenance plans. - Highlights: > A novel algorithm using multi-objective particle swarm optimization technique. > Evaluation of the cost-reliability tradeoff in a flexible maintenance strategy. > A probabilistic model for regression parameters is employed to assess reliability-based performance. > The proposed approach can help decision makers to optimize roadway maintenance plans.

  19. Full scale demonstration of air-purifying pavement

    Energy Technology Data Exchange (ETDEWEB)

    Ballari, M.M., E-mail: ballari@santafe-conicet.gov.ar [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands); Brouwers, H.J.H., E-mail: jos.brouwers@tue.nl [Department of the Built Environment, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven (Netherlands)

    2013-06-15

    Highlights: ? The results of a demonstration project for photocatalytic pavement are shown. ? The photocatalytic performance was studied in a street as well as on lab scale. ? The outdoor monitoring was performed in different seasons and weather conditions. ? The NO{sub x} concentration was in average 19% lowered by the photocatalytic street. ? Under ideal weather conditions the NO{sub x} reduction reached up to 45%. -- Abstract: 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{sub 2} over a length of 150 m (“DeNO{sub x} 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{sub 2} 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 NO{sub x} 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 NO{sub x} concentration decrease of 45% could be observed.

  20. Patología de pavimentos articulados / Pathology of interlocking pavements

    Scientific Electronic Library Online (English)

    Carlos Hernando, Higuera Sandoval; Óscar Fabián, Pacheco Merchán.

    2010-07-01

    Full Text Available Este artículo presenta los resultados de un proyecto de grado sobre patología de pavimentos articulados, el cual fue elaborado con el propósito de hacer una recolección de los deterioros típicos de los pavimentos articulados construidos con adoquines de concreto o de ladrillo; y de esta forma, elabo [...] rar un catálogo de deterioros para este tipo de estructuras que facilitará la identificación y cuantificación de los deterioros en una inspección visual. El segundo propósito de este proyecto, es la formulación para Colombia de una metodología que permita determinar el Índice de Condición de las estructuras de pavimentos articulados. Abstract in english This article presents the results of a thesis on pathology of interlocking pavements, which objective was to make a compilation of typical damages of interlocking pavements constructed with concrete or brick pavers and, in this way, to elaborate a catalogue of damages for this kind of structures whi [...] ch will make the identification and quantification of deteriorations possible in a visual inspection. The second purpose of this project is the formulation of a methodology which allows determining the Index of pavement conditions for Colombia.

  1. Patología de pavimentos articulados Pathology of interlocking pavements

    Directory of Open Access Journals (Sweden)

    Carlos Hernando Higuera Sandoval

    2010-07-01

    Full Text Available Este artículo presenta los resultados de un proyecto de grado sobre patología de pavimentos articulados, el cual fue elaborado con el propósito de hacer una recolección de los deterioros típicos de los pavimentos articulados construidos con adoquines de concreto o de ladrillo; y de esta forma, elaborar un catálogo de deterioros para este tipo de estructuras que facilitará la identificación y cuantificación de los deterioros en una inspección visual. El segundo propósito de este proyecto, es la formulación para Colombia de una metodología que permita determinar el Índice de Condición de las estructuras de pavimentos articulados.This article presents the results of a thesis on pathology of interlocking pavements, which objective was to make a compilation of typical damages of interlocking pavements constructed with concrete or brick pavers and, in this way, to elaborate a catalogue of damages for this kind of structures which will make the identification and quantification of deteriorations possible in a visual inspection. The second purpose of this project is the formulation of a methodology which allows determining the Index of pavement conditions for Colombia.

  2. EVALUATION OF TIRE RUBBER DISPOSAL IN CONCRETE FOR PAVEMENTS

    Directory of Open Access Journals (Sweden)

    Rosa Cristina Cecche Lintz

    2009-12-01

    Full Text Available The production of waste by the tire industry has been a growing problem, indicating the need for its reuse. More than thirty million tires are discharged per year in Brazil, where regulation for the environment states that for each four new tires, five unusable ones must be adequately disposed by manufacturers and importers. Paving consumes an extremely large quantity of materials, which can be the source of rational application of waste and rejected materials. Research shows that tire rubber can be added to asphalt, which increases its durability and improves pavement quality and safety conditions by absorbing the rubber elastic properties, and also be used for architectural applications, among others. This study deals with the addition of rubber fibers from tire crushing in concrete for roadway pavements in order to provide proper indication about the alternative material disposal through an evaluation of the mechanical behavior of the modified concrete. Different concrete mixes were produced, within which, part of fine aggregates were substituted by tire rubber and mechanical experiment tests were performed, which show that, due to great resistance losses, the disposal of this alternative material in concrete should be considered for light traffic pavements, with the addition of rubber ranging up to 10% in mass.

  3. Examining Victimization and Psychological Distress in Transgender College Students

    Science.gov (United States)

    Effrig, Jessica C.; Bieschke, Kathleen J.; Locke, Benjamin D.

    2011-01-01

    Treatment-seeking and non-treatment-seeking transgender college students were examined with regard to victimization and psychological distress. Findings showed that transgender college students had elevated rates of distress as compared with college students who identified as men or women. Results indicated that treatment-seeking and non-treatment…

  4. Psychological distress and mortality in systolic heart failure

    DEFF Research Database (Denmark)

    Pelle, Aline J; Pedersen, Susanne S.

    2010-01-01

    Depression, anxiety, and type D ("distressed") personality (tendency to experience negative emotions paired with social inhibition) have been associated with poor prognosis in coronary heart disease, but little is known about their role in chronic heart failure. Therefore, we investigated whether these indicators of psychological distress are associated with mortality in chronic heart failure.

  5. Intrusive Thoughts: A Primary Variable in Breakup Distress

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2013-01-01

    University students who were high versus low on breakup distress scores were given self-report measures to assess their intrusive thoughts about the romantic breakup and their somatic symptoms that followed the breakup as well as their extracurricular activities and social support that might alleviate their breakup distress. In a regression…

  6. Child Rearing and Children's Prosocial Initiations toward Victims of Distress.

    Science.gov (United States)

    Zahn-Waxler, Carolyn; And Others

    1979-01-01

    Investigates the relation between maternal rearing behavior and the ways children aged 1 1/2 to 2 1/2 years cope with emotions of distress in others. Specifically examined children's reparation for transgression when they were the cause of distress and their altruism when they were bystanders. (JMB)

  7. The Role of Emotional Dysregulation in Perfectionism and Psychological Distress

    Science.gov (United States)

    Aldea, Mirela A.; Rice, Kenneth G.

    2006-01-01

    Data from a sample of university students (N = 349) were used to test a model in which emotional dysregulation (a composite of emotional reactivity and splitting) was expected to account for the effect of perfectionism on general psychological distress. Significant positive effects were observed between maladaptive perfectionism and distress,…

  8. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - presentation

    Science.gov (United States)

    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...

  9. Effects of reclaimed asphalt pavement on indirect tensile strength test of conditioned foamed asphalt mix

    International Nuclear Information System (INIS)

    This paper presents the results of Indirect Tensile Strength (ITS) Test for samples prepared with reclaimed asphalt pavement (RAP). Samples were conditioned in water at 25°C for 24 hours prior to testing. Results show that recycled aggregate from reclaimed asphalt pavement performs as well as virgin aggregate.

  10. AN ASSESSMENT OF THE OPERATIONAL LIFE OF CONCRETE AIRFIELD PAVEMENTS ON THE BASIS OF RELIABILITY THEORY

    OpenAIRE

    Borisov, Yu M.; Barabash, D. E.; Surovtsev, I. S.

    2010-01-01

    The mathematical model of development and accumulation of defects of air-field pavements obtained with the use of the principal dependences of relia-bility theory is proposed. This model is implemented in the method of assessment of an operational life of concrete airfield pavements.

  11. Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site - Abstract

    Science.gov (United States)

    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...

  12. Asphalt Pavement Aging and Temperature Dependent Properties Using Functionally Graded Viscoelastic Model

    Science.gov (United States)

    Dave, Eshan V.

    2009-01-01

    Asphalt concrete pavements are inherently graded viscoelastic structures. Oxidative aging of asphalt binder and temperature cycling due to climatic conditions being the major cause of non-homogeneity. Current pavement analysis and simulation procedures dwell on the use of layered approach to account for these non-homogeneities. The conventional…

  13. Implementation of interactive Web-based training tools in pavement engineering

    OpenAIRE

    Steyn, Wynand J.vdM.

    2010-01-01

    Pavement Interactive, an online pavement community built on an open-source wiki platform, is a novel and possible approach to giving distance training to South African and southern African roads professionals in various aspects of road construction, maintenance and management.

  14. The changing workforce, job stress, and psychological distress.

    Science.gov (United States)

    Marshall, N L; Barnett, R C; Sayer, A

    1997-04-01

    The change in the United States from a manufacturing economy to a service economy has important implications for theoretical models of the relationships between job characteristics and workers' psychological distress. A sample of 600 men and women employed full-time were recruited to test 2 theoretical models. The job demand-control model posits that jobs that are both high in job demands and low in decision latitude are associated with greater psychological distress. The job demand-service model posits that jobs that are high in job demands and low in service to others are associated with greater psychological distress. Results show that the job demand-control model is a significant predictor of psychological distress among employees in the manufacturing industry, whereas the job demand-service model is a significant predictor of psychological distress among employees in the services industries. PMID:9552283

  15. Numerical simulation on the thermal response of heat-conducting asphalt pavements

    International Nuclear Information System (INIS)

    Using asphalt pavements as a solar collector is a subject of current interest all over the world because the sun provides a cheap and abundant source of clean and renewable energy, which can be captured by black asphalt pavements. A heat-conducting device is designed to absorb energy from the sun. In order to validate what parameters are critical in the asphalt collector, a finite element model is developed to predict the thermal response of the heat-conducting device compared to the conventional asphalt mixture. Some factors that may affect the asphalt pavement collector are considered, including the coefficient of heat conductivity of the asphalt pavement, the distance between pipes with the medium, water, and the pipe's diameter. Ultimately, the finite element model can provide pavement engineers with an efficient computational tool that can be a guide to the conductive asphalt solar collector's experiment in the laboratory.

  16. A method for assessing the physical recovery of Antarctic desert pavements following human-induced disturbances: a case study in the Ross Sea region of Antarctica.

    Science.gov (United States)

    O'Neill, Tanya A; Balks, Megan R; López-Martínez, Jerónimo; McWhirter, Judi L

    2012-12-15

    With increasing visitor numbers an understanding of the impacts of human activities in Antarctic terrestrial environments has become important. The objective of this study was to develop a means for assessing recovery of the ground surface desert pavement following physical disturbance. A set of 11 criteria were identified to assess desert pavement recovery. Assessed criteria were: embeddedness of surface clasts; impressions of removed clasts; degree of clast surface weathering; % overturned clasts; salt on underside of clasts; development of salt coatings; armouring per m(2); colour contrast; evidence of subsidence/melt out; accumulation of salt on cut surfaces; and evidence of patterned ground development. Recovery criteria were assigned a severity/extent rating on a scale from zero to four, zero being highly disturbed, and four being undisturbed. A relative % recovery for each criteria was calculated for each site by comparison with a nearby undisturbed control area, and an overall Mean Recovery Index (MRI) was assigned to each pavement surface. To test the method, 54 sites in the Ross Sea region of Antarctica were investigated including areas disturbed by: bulldozer scraping for road-fill, contouring for infrastructure, geotechnical investigations, and experimental treading trial sites. Disturbances had occurred at timescales ranging from one week to 50 years prior to assessment. The extent of desert pavement recovery at the sites investigated in this study was higher than anticipated. Fifty of the 54 sites investigated were in an intermediate, or higher, stage of desert pavement recovery, 30 sites were in an advanced stage of recovery, and four sites were indistinguishable from adjacent control sites (MRI = 100%). It was found that active surfaces, such as the gravel beach deposits at the Greenpeace World Park Base site at Cape Evans, the aeolian sand deposits at Bull Pass, and the alluvial fan deposits of the Loop Moraine field campsite, recovered relatively quickly, whereas less active sites, such as the bulldozed tracks at Marble Point, and Williams Field to McMurdo Station pipeline site on Ross Island, showed only intermediate recovery 20-30 years after disturbance. The slabby grano-diorite surface material at the former Vanda Station site, meant that the impacts that had occurred were hard to detect following decommissioning of the station and site remediation. Desert pavements disturbed by randomly dispersed footprints, temporary field campsites at the Loop Moraine and VXE6 Pond in the Wright Valley, recovered to be undetectable (MRI = 100%) within five years, whereas track formation from repeated trampling, particularly the concentration of larger clasts along the margin of a confined track, persisted for over 15 years (MRI = 82%). The recovery assessment method developed in this study has environmental management applications and potential to advance our ability to predict the recovery of desert pavement following human impacts from activities in Antarctica. PMID:23000478

  17. The interaction between concrete pavement and corrosion-induced copper runoff from buildings.

    Science.gov (United States)

    Bahar, B; Herting, G; Wallinder, I Odnevall; Hakkila, K; Leygraf, C; Virta, M

    2008-05-01

    Changes in chemical speciation of copper and the capacity of concrete pavement to retain copper in runoff water from external buildings have been investigated at urban field conditions, and in parallel laboratory experiments simulating outdoor scenarios. The research study showed the concrete surface to form a copper rich surface layer ( approximately 50 microm thick) upon exposure, and a high capacity to significantly reduce the bioavailable fraction of released copper (20-95%). The retention capacity of copper varied between 5 and 20% during single runoff events in the laboratory, and between 10 and 40% of the total copper release during single natural runoff events. The capacity to retain and reduce the bioavailable fraction of non-retained copper increased with increasing wetness of the concrete surfaces, increasing pH of the runoff water and decreasing flow rates. Bioassay testing with bacterial and yeast bioreporters showed the bioavailable fraction of non-retained copper to be significantly lower than the total copper concentration in the runoff water, between 22 and 40% for bacteria and between 8 and 31% for yeast. The application of generated data to simulate a fictive outdoor scenario, suggests a significant reduction of bioavailable and total copper to background values during environmental entry as a result of dilution, and the interaction with solid surfaces, organic matter and complexing agents already in the drainage system. PMID:17636419

  18. Sharing, liking, commenting, and distressed? The pathway between Facebook interaction and psychological distress.

    Science.gov (United States)

    Chen, Wenhong; Lee, Kye-Hyoung

    2013-10-01

    Studies on the mental health implications of social media have generated mixed results. Drawing on a survey of college students (N=513), this research uses structural equation modeling to assess the relationship between Facebook interaction and psychological distress and two underlying mechanisms: communication overload and self-esteem. It is the first study, to our knowledge, that examines how communication overload mediates the mental health implications of social media. Frequent Facebook interaction is associated with greater distress directly and indirectly via a two-step pathway that increases communication overload and reduces self-esteem. The research sheds light on new directions for understanding psychological well-being in an increasingly mediated social world as users share, like, and comment more and more. PMID:23745614

  19. Neuroleptic-induced acute respiratory distress syndrome

    Scientific Electronic Library Online (English)

    Francisco Garcia, Soriano; Elcio dos Santos Oliveira, Vianna; Irineu Tadeu, Velasco.

    Full Text Available CONTEXTO: Apresentamos um caso de síndrome neuroléptica maligna e de síndrome do desconforto respiratório do adulto relacionada ao uso do neuroléptico. Discutimos a possível relação clínica e as alterações de creatinino-quinase, relaxamento muscular e função respiratória. RELATO DE CASO: Paciente de [...] 41 anos, homem, branco. Internado por otalgia e paralisia facial periférica à direita. A tomografia computadorizada de crânio mostrou uma área hiperdensa de 2 cm de diâmetro na região da artéria intercomunicante anterior. Os exames pré-operatórios revelaram: pH 7.4, PaCO2 40 torr, PaO2 80 torr (em ar ambiente), Hb 13.8 g/dl, nitrogênio uréico no plasma 3.2 mmol/l, e creatinina 90 mmol/l. A radiografia de tórax era normal. O paciente fez jejum de 12 horas previamente à cirurgia. Foram usados na anestesia: halotano, fentanil 0.5 mg e droperidol 25 mg (intravenosa). Após seis horas o paciente apresentava PaO2 65 torr (PCO2 normal) sob FiO2 de 50% (relação PaO2/FiO2 130) e permaneceu neste nível até o final da cirurgia. O achado intraoperatório foi de um aneurisma trombosado, que foi ressecado; o vaso foi clipado. Não havia vasoespasmo. Este caso ilustra que drogas neurolépticas podem causar síndrome maligna por neuroléptico e síndrome do desconforto respiratório do adulto em associação. Contudo, há possibilidade de que o neuroléptico ou o solvente da droga possam produzir síndrome do desconforto respiratório do adulto sem apresentar as manifestações de síndrome maligna por neuroléptico. Esta possibilidade é importante pois, nos pacientes com síndrome do desconforto respiratório do adulto que estejam recebendo neurolépticos, será necessário que se pense em sua substituição, especialmente se o paciente não apresentar outros fatores que possam explicar a síndrome do desconforto respiratório do adulto. Abstract in english CONTEXT: A case of neuroleptic malignant syndrome and acute respiratory distress syndrome is presented and discussed with emphasis on the role of muscle relaxation, creatine kinase, and respiratory function tests. CASE REPORT: A 41-year-old man presented right otalgia and peripheral facial paralysis [...] . A computed tomography scan of the skull showed a hyperdense area, 2 cm in diameter, in the pathway of the anterior intercommunicating cerebral artery. Preoperative examination revealed: pH 7.4, PaCO2 40 torr, PaO2 80 torr (room air), Hb 13.8 g/dl, blood urea nitrogen 3.2 mmol/l, and creatinine 90 mmol/l. The chest x-ray was normal. The patient had not eaten during the 12-hour period prior to anesthesia induction. Intravenous halothane, fentanyl 0.5 mg and droperidol 25 mg were used for anesthesia. After the first six hours, the PaO2 was 65 torr (normal PaCO2) with FiO2 50% (PaO2/FiO2 130), and remained at this level until the end of the operation 4 hours later, maintaining PaCO2 at 35 torr. A thrombosed aneurysm was detected and resected, and the ends of the artery were closed with clips. No vasospasm was present. This case illustrates that neuroleptic drugs can cause neuroleptic malignant syndrome associated with acute respiratory distress syndrome. Neuroleptic malignant syndrome is a disease that is difficult to diagnose. Acute respiratory distress syndrome is another manifestation of neuroleptic malignant syndrome that has not been recognized in previous reports: it may be produced by neuroleptic drugs independent of the manifestation of neuroleptic malignant syndrome. Some considerations regarding the cause and effect relationship between acute respiratory distress syndrome and neuroleptic drugs are discussed. Intensive care unit physicians should consider the possibility that patients receiving neuroleptic drugs could develop respiratory failure in the absence of other factors that might explain the syndrome.

  20. Escurrimiento en pavimentos de bloques de suelo-cemento: un abordaje experimental / Runoff on Pavements of Soil-Cement Blocks - an Experimental Boarding

    Scientific Electronic Library Online (English)

    Jorge Luis, Zegarra-Tarqui; Jeferson, Santos-De Brito; Miriam, De Fátima-Carvalho.

    2015-03-01

    Full Text Available El artículo evalúa la reducción del escurrimiento superficial en pavimentos construidos con bloques rectangulares de suelo-cemento. Los ensayos fueron realizados en un pavimento piloto con bloques de suelo-cemento, asentados en una caja metálica de 50 cm × 50 cm (área = 2500 cm²), con pendientes de [...] 1, 3 y 5%. Se utilizaron intensidades medias de 76.9 mm/h y 117.7 mm/h, valores próximos a las intensidades calculadas por la curva intensidad-duración-frecuencia (i-d-f) de la ciudad del Salvador, Brasil, para tiempo de retorno de 2 y 5 años, respectivamente. El coeficiente de escurrimiento medio fue C = 0.61, este valor es cercano al coeficiente de pavimento con bloques rectangulares (C = 0.6) y es inferior al valor del coeficiente de pavimento de bloque de concreto (C = 0.78). Por otro lado, si consideramos que las áreas mayores que 2500 cm² son compuestas por el acoplamiento de unidades de área de 50 × 50 centímetros, entonces, las pérdidas por salpicamiento forman parte del escurrimiento superficial, obteniendo el coeficiente Csuperficial+salpicamiento, el cual presentó valores en la faja de 0.74 a 0.89; estos valores se encuentran cerca del coeficiente de pavimento de bloque de cemento (C = 0.78) y son inferiores al de pavimento de concreto (C = 0.95), pero considerando factores como tiempo de desplazamiento del escurrimiento sobre la superficie, depresiones en la superficie, evaporación y rugosidad del pavimento, entre otros, este valor debe disminuir. Entonces, el pavimento de bloques de suelo-cemento puede considerarse dentro de la categoría de semipermeable para las dimensiones de área utilizadas. Abstract in english The article evaluates the reduction of runoff in pavements constructed with rectangular blocks of soil-cement. The tests were conducted in a pilot pavement built with soil-cement blocks, seated in a metal box of 50 cm × 50 cm (area = 2500 cm²), with declivities of 1%, 3% and 5%. Mean intensities of [...] 76.9 mm / I 117.7 mm / h were used, values close to the intensities calculated by intensity-frequency-duration (i-f-d) equation of the city of Salvador, Brazil, for return periods of 2 and 5 years, respectively. The medium runoff coefficient was C = 0.61, this value is close to the coefficient of pavement with rectangular blocks (C = 0.6) and it has a lower value than the coefficient for concrete block pavement (C = 0.78). On the other hand, considering that areas with more than 2500 cm² are constituted by coupling of area units of 50 cm × 50 cm, the splash losses are part of the runoff, obtaining the coefficient Csuperficial + splashing, which showed values in the 0.74 to 0.89 range, these values were found close to the coefficient of concrete block pavement (C = 0.78) and below the concrete pavement (C = 0.95), respectively, but factors such as displacement time of runoff on surface, depressions on the surface, roughness of pavement, evaporation and others, should reduce this value. Then, the pavement of soil-cement blocks can be considered in the category of semi-permeable for the area size used.

  1. Evaluation of Emotional Distress in Breast Cancer Patients

    Directory of Open Access Journals (Sweden)

    Hamid Saeedi-Saedi

    2015-02-01

    Full Text Available Background: Cancer has been known as a class of dangerous diseases which cause tremendous physical and emotional problems to both patients and their families. In spite of medical advances, cancer is still considered to be equal with death and pain. This study aims to analyze the emotional distress and the causes in breast cancer patients. Methods: This study was a quantitative study which tries to analyze the emotional distress in 82 breast cancer patients referred to the Radiotherapy and Oncology Department of Razi Hospital in Rasht, northern Iran. In this study, the emotional distress is analyzed based on a standard questionnaire which contains demographic information, distress thermometer, and a section devoted to the probable causes. Results: Among the 82 patients that participated in this study, 32 patients (39% suffered from severe emotional distress which had a statistically significant relationship (p<0.009 with the functional status of the patients. Taking care of children, fear, anxiety, difficulties of taking bath and wearing clothes, family problems, fever and nasal dryness are the most common issued related to emotional distress. Conclusion: Emotional distress can affect the quality of life of breast cancer patients. Therefore, oncology specialists should utilize mental health services to improve their patients’ mental health as well as to control the consequences of the disease.

  2. The five steps of comprehensive psychosocial distress screening.

    Science.gov (United States)

    Lazenby, Mark; Tan, Hui; Pasacreta, Nick; Ercolano, Elizabeth; McCorkle, Ruth

    2015-05-01

    Despite the growing recognition of the impact psychosocial distress has on the quality of life of patients with cancer, the implementation of the National Comprehensive Cancer Network (NCCN) Distress Management Guidelines and the mandate of evidence-based policy for routine distress screening continue to lag. To speed adoption of the guideline, the American Psychosocial Oncology Society (APOS) and Yale School of Nursing (YSN) launched the Screening for Psychosocial Distress Program in 2014. The program resulted in the development of five steps necessary to carry out routine psychosocial distress screening. The steps are consistent with the NCCN Distress Management Guidelines and the new criterion for accreditation by the American College of Surgeons (ACS) Commission on Cancer as of 2015. These five steps are as follows: (1) screening, (2) evaluating, (3) referring, (4) following up, and (5) documenting and quality improvement. The purpose of this article is to summarize the detailed procedure of the five steps for cancer care professionals-including oncologists, nurses, psychiatrists, psychologists, and social workers-so they can manage psychosocial distress efficiently in their own clinical environments. PMID:25824699

  3. Psychological and physical distress of cancer patients during radiotherapy

    International Nuclear Information System (INIS)

    Purpose: patients undergoing radiotherapy have physical and psychological symptoms related to the underlying disease and the treatment. In order to give the best possible support to the patients, more knowledge about the amount and the changing of distress in the course of radiotherapy is of essentially importance. Methods: The distress was measured in a consecutive sample of cancer patients (n=82) undergoing radiotherapy. Each patient was given the EORTC-QLQ-C30, the HADS and a special questionnaire which ascertain radiotherapy-specific items before starting the radiotherapy, at the onset of radiotherapy, in the third week of radiotherapy and 3 weeks after the end of radiotherapy. Results: within the first week of treatment the psychological distress of the patients is increasing; 98.8 % of the patients are 'moderate distressed', 46 % 'severe distressed'. General physical symptoms seem not to be affected by the radiotherapy, there is no changing. The distress caused by the organization of the radiotherapy is decreasing, while therapy-related symptoms are increasing in the course of radiotherapy. Even after the end of the therapy these symptoms keep on causing distress, sometimes in a higher amount than before. A correlation between sex, sort of cancer and curative or palliative treatment and the amount of distress was found. Conclusion: the results stress the importance of adequate emotional support for patients undergoing radiotherapy especially in the first week ofdiotherapy especially in the first week of treatment and after the treatment. There is a need for the development of a valid radiotherapy - questionnaire in order to be able to measure the distress of these patients. (author)

  4. Preschoolers' responses to peers' distress and beliefs about bystander intervention.

    Science.gov (United States)

    Caplan, M Z; Hay, D F

    1989-03-01

    The spontaneous responses of 27 3-5-yr-olds to the distress of their peers were recorded in the classroom. Individual interviews were also conducted to assess the children's understanding of social norms governing bystander intervention. Findings indicated that the children often paid attention to distressed peers, and many were capable of active intervention. Overall, however, a low rate of prosocial responding was observed. The interviews revealed that the children held systematic beliefs about how to aid a distressed companion, but did not believe they were supposed to help when competent adult caregivers were present. PMID:2708463

  5. Termômetro de Distress: validação de um instrumento breve para avaliação diagnóstica de pacientes oncológicos Distress Thermometer: validation of a brief screening instrument to detect distress in oncology patients

    Directory of Open Access Journals (Sweden)

    Cristiane Sant'Anna Decat

    2009-12-01

    Full Text Available A literatura especializada disponibiliza instrumentos de medida de estresse de aplicação geral, os quais vêm sendo empregados em diferentes contextos ocupacionais e em saúde. Mas, desde 1997, a National Comprehensive Cancer Network (NCCN recomenda a adoção de uma medida específica para pacientes oncológicos. Considerando, portanto, o interesse clínico e científico de desenvolver futuros estudos de meta-análise em Oncologia, que incluam amostras brasileiras, realizaram-se a adaptação e a validação do Termômetro de Distress (TD. A eficácia de avaliação do TD foi verificada por meio da comparação com a Escala de Ansiedade e Depressão (HAD, um instrumento clinicamente estabelecido de avaliação de distress. Para tanto, avaliou-se uma amostra de 83 pacientes, que responderam ao TD e ao HAD. Os dados foram submetidos ao SPSS 15.0. Os resultados indicam uma sensibilidade de 82% e uma especificidade de 98%, o que indica que o TD é viável e eficiente para avaliar o distress psicológico.The specialized literature provides instruments measuring stress for general application. Those instruments have been employed in occupational and health contexts. But since 1997, the National Comprehensive Cancer Network (NCCN recommends the adoption of a specific measuring instrument for the assessment of cancer patients. Considering the existence of clinical and scientific interest to develop future meta-analysis studies in the field of Oncology, which will include Brazilian samples, the adaptation and validation of the Distress Thermometer (TD was undertaken. The effectiveness of the TD in assessing distress was verified by comparison with the Anxiety and Depression Scale (HAD, a clinically established tool for evaluating distress. In order to that, a sample of 83 patients answered the TD and the HAD. The data were analyzed using SPSS 15.0. Results of the analysis indicated 82% for sensitivity and 98% for specificity. Using the TD appeared feasible and effective for psychological distress screening.

  6. Termômetro de Distress: validação de um instrumento breve para avaliação diagnóstica de pacientes oncológicos / Distress Thermometer: validation of a brief screening instrument to detect distress in oncology patients

    Scientific Electronic Library Online (English)

    Cristiane Sant' Anna, Decat; Jacob Arie, Laros; Tereza Cristina Cavalcanti Ferreira de, Araujo.

    2009-12-01

    Full Text Available A literatura especializada disponibiliza instrumentos de medida de estresse de aplicação geral, os quais vêm sendo empregados em diferentes contextos ocupacionais e em saúde. Mas, desde 1997, a National Comprehensive Cancer Network (NCCN) recomenda a adoção de uma medida específica para pacientes on [...] cológicos. Considerando, portanto, o interesse clínico e científico de desenvolver futuros estudos de meta-análise em Oncologia, que incluam amostras brasileiras, realizaram-se a adaptação e a validação do Termômetro de Distress (TD). A eficácia de avaliação do TD foi verificada por meio da comparação com a Escala de Ansiedade e Depressão (HAD), um instrumento clinicamente estabelecido de avaliação de distress. Para tanto, avaliou-se uma amostra de 83 pacientes, que responderam ao TD e ao HAD. Os dados foram submetidos ao SPSS 15.0. Os resultados indicam uma sensibilidade de 82% e uma especificidade de 98%, o que indica que o TD é viável e eficiente para avaliar o distress psicológico. Abstract in english The specialized literature provides instruments measuring stress for general application. Those instruments have been employed in occupational and health contexts. But since 1997, the National Comprehensive Cancer Network (NCCN) recommends the adoption of a specific measuring instrument for the asse [...] ssment of cancer patients. Considering the existence of clinical and scientific interest to develop future meta-analysis studies in the field of Oncology, which will include Brazilian samples, the adaptation and validation of the Distress Thermometer (TD) was undertaken. The effectiveness of the TD in assessing distress was verified by comparison with the Anxiety and Depression Scale (HAD), a clinically established tool for evaluating distress. In order to that, a sample of 83 patients answered the TD and the HAD. The data were analyzed using SPSS 15.0. Results of the analysis indicated 82% for sensitivity and 98% for specificity. Using the TD appeared feasible and effective for psychological distress screening.

  7. Design Basis for Fibre Reinforced Concrete (FRC) Pavements

    DEFF Research Database (Denmark)

    Bendixen, SØren; Stang, Henrik

    1996-01-01

    The paper summarises a Ph.D. project on development of a new design basis for fibre reinforced concrete ground slabs. The stress-crack openingrelationship is a well know basic material property of theso-called fictitious crack model for concrete. In the presentstudy it is shown how the stress-crack opening relationship can beused to descibe the properties of fibre reinforced concrete (FRC) intension and how the stress-crack opening relationship can beapplied in a simple design scheme for pavements. The projectincludes development of design tools, experiments to determine thestress-crack opening relationship by direct tension tests and fullscale tests on FRC-slabs cast on ground.

  8. Development of traffic induced permanent strain in concrete block pavements:

    OpenAIRE

    Huurman, M.

    1996-01-01

    Concrete block pavements (c.b.p.) commonly consist of concrete blocks placed over a granular substructure. As a result of wheel load passages permanent strains will slowly develop in the substructure and cause rutting. This paper is about the prediction of the permanent strain development in the substructure and the associated rutting on the basis of the results of repeated load triaxial tests and analytical models. By discussing the behaviour of three c.b.p.'s it is shown that insight int...

  9. Study of Sand Characteristics as Bearing and Filler in Joint of Inter-locking Concrete Block Pavement

    Directory of Open Access Journals (Sweden)

    Rosli Hainin

    2009-09-01

    Full Text Available The use of interlocking concrete block pavement as a road surface has increased in the road constructionrecently. This study was conducted to envisage the problems occur particularly for the bedding and joint filling sand of the interlocking concrete block pavement. Moreover, the effect of the moisture on the bedding sandwas also studied. Two type of additives namely as palm oil fly ash (POFA and silica fume, which carry thepozzolanic behaviour, were mixed with joint filling sand in order to improve its quality. These materials areindustrial waste compound which can be easily found in Malaysia. Two types of permeability experiments,the constant and falling head tests were conducted to evaluate the permeability of the joint filling sands withthe percentage additives used of 2%, 4%, 6%, 8% and 10%. A physical model was developed to investigatethe degree of compaction and water absorption via sand in joints. Water absorption test was also conductedonto the model with the addition of additives of 0%, 5% and 10% with the joint filling sand for 5 and 10days. Study shown that the incorporation of additives reduced the permeability of joint filling sand withthe optimum values obtained for both POFA and silica fume mixtures both were at 2% respectively.

  10. Lung tissue remodeling in the acute respiratory distress syndrome

    Scientific Electronic Library Online (English)

    Alba Barros de, Souza; Flavia Brandão dos, Santos; Elnara Marcia, Negri; Walter Araujo, Zin; Patricia Rieken Macedo, Rocco.

    2003-08-01

    Full Text Available Acute respiratory distress syndrome (ARDS) is characterized by diffuse alveolar damage, and evolves progressively with three phases: exsudative, fibroproliferative, and fibrotic. In the exudative phase, there are interstitial and alveolar edemas with hyaline membrane. The fibropro­liferative phase i [...] s characterized by exudate organization and fibroelastogenesis. There is proliferation of type II pneumocytes to cover the damaged epithelial surface, followed by differentiation into type I pneumocytes. The fibroproliferative phase starts early, and its severity is related to the patient’s prognosis. The alterations observed in the phenotype of the pulmonary parenchyma cells steer the tissue remodeling towards either progressive fibrosis or the restoration of normal alveolar architecture. The fibrotic phase is characterized by abnormal and excessive deposition of extracellular matrix proteins, mainly collagen. The dynamic control of collagen deposition and degradation is regulated by metalloproteinases and their tissular regulators. The deposition of proteoglycans in the extracellular matrix of ARDS patients needs better study. The regulation of extracellular matrix remodeling, in normal conditions or in several pulmonary diseases, such as ARDS, results from a complex mechanism that integrate the transcription of elements that destroy the matrix protein and produce activation/inhibition of several cellular types of lung tissue. This review article will analyze the ECM organization in ARDS, the different pulmonary parenchyma remodeling mechanisms, and the role of cytokines in the regulation of the different matrix components during the remodeling process.

  11. Lung tissue remodeling in the acute respiratory distress syndrome

    Directory of Open Access Journals (Sweden)

    Souza Alba Barros de

    2003-01-01

    Full Text Available Acute respiratory distress syndrome (ARDS is characterized by diffuse alveolar damage, and evolves progressively with three phases: exsudative, fibroproliferative, and fibrotic. In the exudative phase, there are interstitial and alveolar edemas with hyaline membrane. The fibropro­liferative phase is characterized by exudate organization and fibroelastogenesis. There is proliferation of type II pneumocytes to cover the damaged epithelial surface, followed by differentiation into type I pneumocytes. The fibroproliferative phase starts early, and its severity is related to the patient?s prognosis. The alterations observed in the phenotype of the pulmonary parenchyma cells steer the tissue remodeling towards either progressive fibrosis or the restoration of normal alveolar architecture. The fibrotic phase is characterized by abnormal and excessive deposition of extracellular matrix proteins, mainly collagen. The dynamic control of collagen deposition and degradation is regulated by metalloproteinases and their tissular regulators. The deposition of proteoglycans in the extracellular matrix of ARDS patients needs better study. The regulation of extracellular matrix remodeling, in normal conditions or in several pulmonary diseases, such as ARDS, results from a complex mechanism that integrate the transcription of elements that destroy the matrix protein and produce activation/inhibition of several cellular types of lung tissue. This review article will analyze the ECM organization in ARDS, the different pulmonary parenchyma remodeling mechanisms, and the role of cytokines in the regulation of the different matrix components during the remodeling process.

  12. Pollutant load removal efficiency of pervious pavements: is clogging an issue?

    Science.gov (United States)

    Kadurupokune, N; Jayasuriya, N

    2009-01-01

    Pervious pavements in car parks and driveways reduce the peak runoff rate and the quantity of runoff discharged into urban drains as well as improve the stormwater quality by trapping the sediments in the infiltrated water. The paper focuses on presenting results from the laboratory tests carried out to evaluate water quality improvements and effects of long-term decrease in infiltration rates with time due to sediments trapping (clogging) within the pavement pores. Clogging was not found to be a major factor affecting pervious pavement performance after simulating 17 years of stormwater quality samples. PMID:19809141

  13. 33 CFR 175.130 - Visual distress signals accepted.

    Science.gov (United States)

    2010-07-01

    ...required, may be used to meet both day and night requirements. Examples —the...024 or 160.036) meets both day and night requirements. Three hand held...distress light (161.013) meet both day and night requirements. Table...

  14. A practical approach to adult acute respiratory distress syndrome

    OpenAIRE

    Manthous, Constantine A.

    2010-01-01

    Acute respiratory distress syndrome (ARDS) is a common disease encountered in hospitalized adult patients that, historically, has carried a very high mortality. This article reviews the clinical features and how pathophysiology informs the evidence-based management of ARDS.

  15. Subjectively reported symptoms in patients with persistent atrial fibrillation and emotional distress

    OpenAIRE

    NinaKupper; JosWiddershoven

    2013-01-01

    Background: Patients with atrial fibrillation (AF) are characterized by emotional distress and poor quality of life. Little is known about the relation between emotional distress and subjectively reported AF symptoms. Our aims were to compare emotional distress levels in AF patients with distress levels in the general population and to examine the cross-sectional and prospective relationship between subjective AF symptom reports and emotional distress around electrical cardioversion (ECV). ...

  16. Proportioning of Steel Fibre Reinforced Concrete Mixes for Pavement Construction and Their Impact on Environment and Cost

    Directory of Open Access Journals (Sweden)

    Stelios Kallis

    2011-07-01

    Full Text Available Steel fibre reinforced concrete (SFRC is a construction material investigated for more than 40 years including for pavement applications. A number of studies have demonstrated the technical merits of SFRC pavements over conventional concrete pavements; however little work has been carried out on the environmental and economical impact of SFRC during the pavement’s life cycle. Therefore, extended research was undertaken within the framework of the EU funded project “EcoLanes” to estimate the environmental and economical loadings of SFRC pavements. The innovative concept of the project is the use of recycled steel tyre-cord wire as concrete fibre reinforcement, which provides additional environmental benefits for tyre recycling over landfilling. Within the project framework a demonstration of a steel-fibre-reinforced roller-compacted concrete (SFR-RCC pavement was constructed in a rural area in Cyprus. In order to assess the economical and environmental picture of the demonstration pavement, life cycle cost analysis (LCCA and life cycle assessment (LCA studies were undertaken, which also compared the under study pavement design with four conventional alternatives. The main output of the studies is that SFR-RCC is more environmentally and economically sustainable than others. In addition, various concrete mix designs were investigated by considering parameters such as fibre type and dosage, cement type, and transportation distances to the construction site. Fibre dosage has been highlighted as a crucial factor compared with economical and environmental loadings in SFR-RCC pavement construction.

  17. Sustainable Drainage Practices in Spain, Specially Focused on Pervious Pavements

    Directory of Open Access Journals (Sweden)

    Jorge Rodriguez-Hernandez

    2013-01-01

    Full Text Available The Spanish climate is full of contrasts, with torrential rains and long droughts; under these conditions, appropriate water management is essential. In Spain, until the end of the twentieth century, water management and legislative development lagged behind other more developed countries. Nowadays, great efforts are being made to reverse this situation and improve both water management and legislation in order to control the two main problems related to stormwater management in cities: floods and diffuse pollution. In this context, Sustainable Urban Drainage Systems (SUDS were developed as the main solution to these problems. The study of these techniques started in the 1970s in the USA, but they were not studied in Spain until 1993 when the University of Cantabria and CLABSA started to look into solutions for stormwater management. After 20 years of research and application, sustainable drainage in Spain is still behind other countries in spite of the efforts to change this situation, notably by the University of Cantabria with 10 years of experience in these techniques, mainly regarding pervious pavements, where more than 13 related research projects have been carried out. The future challenges focus on the application of pervious pavements for Urban Hydrological Rehabilitation.

  18. Finite Element Investigation of the Deterioration of Doweled Rigid Pavements

    CERN Document Server

    Ghauch, Ziad G

    2011-01-01

    The purpose of this study is to describe the failure of concrete around dowel bars in jointed rigid pavements, and the resulting effect on the pavement performance. In fact, under repetitive vehicle loading, concrete in contact with the dowel bar deteriorates, particularly at the joint face. The degradation of concrete around the dowel negatively affects the latter's performance in terms of transferring wheel loads through vertical shear action. In this context, a nonlinear 3D Finite Element analysis was performed using the commercial FE code Abaqus (v-6.11). The FE model was validated with classical analytical solutions of shear and moment along the dowel. A concrete damaged plasticity model was used for the PCC slab to model the degradation of concrete matrix around the dowels under incremental loading. Results obtained show, among other things, that the degradation of concrete matrix around the dowel was found to initiate at the face of the joint and propagate towards the interior of the dowel. Also, resul...

  19. A System for Road Pavement Composite Material Deformation

    Directory of Open Access Journals (Sweden)

    2012-12-01

    Full Text Available

    For a comprehensive experimental evaluation of the material quality, forecast of the properties and parameter change of the bituminous material was made at the time under the impact of external factors, they are subjected to the necessary tests. In the article the automated set Tomsk-Asphalt-Test for determining the elastic modulus of the specimens made of bituminous materials was used in road pavements, maximally close to natural conditions of operation of highways of the Siberian region inRussiaare described. The automated set contains: electromechanical, climate, electronic, PC and software subsystem. The operation principle is a short-time deformation of the asphalt specimens; measurement of physical values: the stress, strain, variation of the size line and temperature of the asphalt pavement material test specimen, converting the measured values into electrical signals, their program processing and visualization. The control of testing and viewing results of measurements is carried out in accordance with the menu software subsystem. The results of calculations: the maximum values of vertical load the difference between the maximum horizontal deformation value and the value measured last after specimen of asphalt material loading for each test cycle, the sum of the differences of the horizontal deformation values of the two sensors and modulus of elasticity.

  20. Emotional and Physical Distress Relief Using a Novel Endorphinergic Formulation

    Directory of Open Access Journals (Sweden)

    Steven Crain

    2013-09-01

    Full Text Available While the endogenous opioid system has generally been associated with regulation of pain, it also modulates the experience of distress and may play a central role in many psychiatric and neurodevelopmental disorders. Decades of preclinical research on the analgesic effects of endogenous opioids, i.e., endorphins, suggests that opioid receptors have plastic bimodal (inhibitory/excitatory properties that may explain conflicting findings in clinical research. An exploratory study with 60 healthy volunteer participants, using a cold pressor-induced pain paradigm, found evidence that a combination of a nutraceutical agent that enhances endorphin release (Endorphin Enhancer with one that switches opioid receptors from an excitatory to inhibitory mode (Opioid Receptor Switcher not only increases pain tolerance but also reduces emotional and physical distress. This discovery led to clinical application of a critically formulated endorphinergic treatment in 203 case studies over a two-year period. Findings revealed the remarkable clinical efficacy and safety of this treatment in the relief of chronic emotional and physical distress, including anxiety, anger, depression, cravings, and hyperalgesia, as well as enhancement of well-being, productivity, mental clarity, relationships, and an adaptive response to life’s stresses. These studies provide new insights into the role of endogenous opioid system imbalances in the development, treatment, and prevention of dysfunctional emotional and physical distress. We postulate that an Endorphinergic Distress Syndrome (EDS consists of abnormal endorphin levels together with opioid receptors predominately in their excitatory mode. EDS may account for many core distress symptoms associated with chronic anxiety, addictions, pain, as well as affective personality, autism spectrum, attention-deficit, and distress-related medical problems. Our research has led to new endorphinergic formulations, combining Endorphin Enhancers, such as caffeine, with Opioid Receptor Switchers, such as n-acetylcysteine, for the relief of emotional and physical distress. Our studies also provide a novel method to reverse the anxiogenic effects of caffeine and related hyperexcitatory substances.

  1. Narcissistic Personality Disorder: Relations with distress and functional impairment

    OpenAIRE

    Miller, Joshua D.; Campbell, W. Keith; Pilkonis, Paul A.

    2007-01-01

    This study examined the construct validity of Narcissistic Personality Disorder (NPD) by examining the relations between NPD and measures of psychological distress and functional impairment both concurrently and prospectively across two samples. In particular, the goal was to address whether NPD typically “meets” Criterion C of the DSM-IV definition of Personality Disorder, which requires that the symptoms lead to clinically significant distress or impairment in functioning. Sample 1 (N =...

  2. Parental separation and adult psychological distress: material and relational pathways

    OpenAIRE

    Lacey, R. E.

    2012-01-01

    The association between parental separation occurring during childhood and adult psychological distress is well established, however the potential mechanisms involved in translating the experience of parental separation into the increased risk of reporting psychological distress is unclear and little investigated. Previous literature indicates that material and relational factors may be involved and that these two pathways are likely to be linked across the life course. The identification of ...

  3. Respiratory distress during endoscopy--report of an unusual case.

    OpenAIRE

    Narendranathan, M.; Kalam, A.

    1987-01-01

    A 30 year old man developed severe respiratory distress during upper gastrointestinal endoscopy. He had a short oesophagus and part of the stomach was intrathoracic. Air-insufflation during endoscopy caused distension of the stomach inside the chest leading to respiratory distress. When part of the stomach is intrathoracic, the endoscopist should be cautious and the possibility of respiratory embarrassment kept in mind during air-insufflation.

  4. Respiratory distress during endoscopy--report of an unusual case.

    Science.gov (United States)

    Narendranathan, M; Kalam, A

    1987-09-01

    A 30 year old man developed severe respiratory distress during upper gastrointestinal endoscopy. He had a short oesophagus and part of the stomach was intrathoracic. Air-insufflation during endoscopy caused distension of the stomach inside the chest leading to respiratory distress. When part of the stomach is intrathoracic, the endoscopist should be cautious and the possibility of respiratory embarrassment kept in mind during air-insufflation. PMID:3444807

  5. Distress Tolerance Scale: A Study of Reliability and Validity

    OpenAIRE

    Sargin, Ahmet Emre; O?zdel, Kadir; Utku, Cisem; Erkan Kuru; Hakan Turkcapar, M.

    2012-01-01

    Objective: Distress Tolerance Scale (DTS) is developed by Simons and Gaher in order to measure individual differences in the capacity of distress tolerance.The aim of this study is to assess the reliability and validity of the Turkish version of DTS. Method: One hundred and sixty seven university students (male=66, female=101) participated in this study. Beck Anxiety Inventory (BAI), State-trait Anxiety Inventory (STAI) and Discomfort Intolerance Scale (DIS) were used to deter...

  6. MGNREGS, Rural Employment and Distress Migration: A study in Odisha

    OpenAIRE

    Parida, Jajati Keshari

    2015-01-01

    This paper attempts to study the role of MGNREGS in improving the household living standards and it impact on seasonal distress out-migration, conducting a primary survey of 400 households from Mayurbhanj and Jajpur districts of Odisha during 2011-12. The major findings suggest that MGNREGS has contributed enormously in creating job opportunities for the needy poor and socially backward households. The accessibility of NREGS prevented huge number of distress seasonal out migration and brought...

  7. Perceived Discrimination and Psychological Distress of Myanmar Refugees in Malaysia

    OpenAIRE

    Sew Kim Low; Jin Kuan Kok; Wan Ying Lee

    2014-01-01

    The purpose of this research is to explore the psychological distress and discrimination experienced by refugees from Myanmar in Malaysia. A narrative inquiry approach and an in depth interview were chosen to get in touch with the social world of the refugees. Bronfenbrenner’s (1979) ecological theory was used to examine the psychological distress of the participants in their social context. The findings revealed the social, economical and psychological discrimination experienced by these r...

  8. Asian elephants (Elephas maximus) reassure others in distress

    OpenAIRE

    Plotnik, Joshua M.; Waal, Frans B. M.

    2014-01-01

    Contact directed by uninvolved bystanders toward others in distress, often termed consolation, is uncommon in the animal kingdom, thus far only demonstrated in the great apes, canines, and corvids. Whereas the typical agonistic context of such contact is relatively rare within natural elephant families, other causes of distress may trigger similar, other-regarding responses. In a study carried out at an elephant camp in Thailand, we found that elephants affiliated significantly more with othe...

  9. Reducing teachers' psychological distress through a mindfulness training program

    OpenAIRE

    Franco, Clemente; Cangas, Adolfo J.; Moreno San Pedro, Emilio; Gallego, José

    2010-01-01

    Teachers constitute one of the professional collectives most affected by psychological problems. The purpose of this quasi-experimental study is to examine the efficacy of a mindfulness training programme to reduce psychological distress in a group of teachers. The sample comprised 68 teachers of Secondary School Education, from various public schools; half of them formed the experimental group, and the another half the control group. The levels of psychological distress were measured, in bot...

  10. Prediction of Financial Distress -A Case Study of Indian Companies

    OpenAIRE

    Amalendu Bhunia; Sri Islam Uddin Khan; Somnath Mukhuti

    2011-01-01

    Financial distress is of crucial importance in financial management especially in the case of competitive environment. Failure is not an impulsive outcome and it grows constantly in stages. A spontaneous protective effort could be accommodated if the company is anticipated to be proceeding in the direction of potential bankruptcy and this can help alleviate the financial distress to all investors and decrease the costs of bankruptcy. This study extends a failure prediction model for Indian co...

  11. Fibromyalgia: When Distress Becomes (Un)sympathetic Pain

    OpenAIRE

    Manuel Martinez-Lavin

    2011-01-01

    Fibromyalgia is a painful stress-related disorder. A key issue in fibromyalgia research is to investigate how distress could be converted into pain. The sympathetic nervous system is the main element of the stress response system. In animal models, physical trauma, infection, or distressing noise can induce abnormal connections between the sympathetic nervous system and the nociceptive system. Dorsal root ganglia sodium channels facilitate this type of sympathetic pain. Similar mechanisms may...

  12. Does intergenerational mobility shape psychological distress? Sorokin revisited

    OpenAIRE

    Houle, Jason N.; Martin, Molly A.

    2011-01-01

    Drawing from Sorokin's hypothesis that socially mobile individuals are at greater risk of experiencing psychological distress than their non-mobile counterparts, we investigate whether intergenerational occupational mobility influences psychological distress, as measured by the Center for Epidemiologic Studies Depression (CES-D) scale. Using data for men from the Wisconsin Longitudinal Study (WLS) and Sobel's Diagonal Mobility Models, we find little evidence for Sorokin's hypothesis; mobile i...

  13. Prevalence and etiology of respiratory distress in newborns

    International Nuclear Information System (INIS)

    Objective: To determine the prevalence and etiology of respiratory distress in the newborns delivered over the period of one year from 1st January 2008 to 31st Dec 2008. Study Design: A descriptive study Place and Duration of Study: The study was conducted in Armed Forces Hospital Sharurah Kingdom of Saudi Arabia over a period of one year from January 2008 to Dec 2008 Patients and methods: All live newborns delivered at Armed Forces Hospital Sharurah during the study period were included and observed for development of respiratory distress. Results: All newborns (n=659), delivered at this hospital over the period of 12 months, were observed for respiratory distress. The overall prevalence of respiratory distress (RD) was 4.24%. Prevalence was 19.7% in preterm and 2.3% in full term. Transient tachypnea of newborn(TTN) was found to be the commonest 35.7% cause of Respiratory Distress (RD) followed by Hyaline membrane disease (HMD) 25%, meconium aspiration syndrome (MAS) 17.9%, congenital pneumonia 7.1% and other congenital anomalies 14.3%. TTN was found to be common among both term and preterm babies, while hyaline membrane disease was seen among preterm, and meconium aspiration syndrome among term and post term babies. Conclusion: Respiratory distress is a common neonatal problem with significant morbidity and mortality. Majority of cases are due to TTN followed by hyaline membrane disease and meconium aspiration syndrome. (author)hor)

  14. Asian elephants (Elephas maximus) reassure others in distress.

    Science.gov (United States)

    Plotnik, Joshua M; de Waal, Frans B M

    2014-01-01

    Contact directed by uninvolved bystanders toward others in distress, often termed consolation, is uncommon in the animal kingdom, thus far only demonstrated in the great apes, canines, and corvids. Whereas the typical agonistic context of such contact is relatively rare within natural elephant families, other causes of distress may trigger similar, other-regarding responses. In a study carried out at an elephant camp in Thailand, we found that elephants affiliated significantly more with other individuals through directed, physical contact and vocal communication following a distress event than in control periods. In addition, bystanders affiliated with each other, and matched the behavior and emotional state of the first distressed individual, suggesting emotional contagion. The initial distress responses were overwhelmingly directed toward ambiguous stimuli, thus making it difficult to determine if bystanders reacted to the distressed individual or showed a delayed response to the same stimulus. Nonetheless, the directionality of the contacts and their nature strongly suggest attention toward the emotional states of conspecifics. The elephants' behavior is therefore best classified with similar consolation responses by apes, possibly based on convergent evolution of empathic capacities. PMID:24688856

  15. Asian elephants (Elephas maximus reassure others in distress

    Directory of Open Access Journals (Sweden)

    Joshua M. Plotnik

    2014-02-01

    Full Text Available Contact directed by uninvolved bystanders toward others in distress, often termed consolation, is uncommon in the animal kingdom, thus far only demonstrated in the great apes, canines, and corvids. Whereas the typical agonistic context of such contact is relatively rare within natural elephant families, other causes of distress may trigger similar, other-regarding responses. In a study carried out at an elephant camp in Thailand, we found that elephants affiliated significantly more with other individuals through directed, physical contact and vocal communication following a distress event than in control periods. In addition, bystanders affiliated with each other, and matched the behavior and emotional state of the first distressed individual, suggesting emotional contagion. The initial distress responses were overwhelmingly directed toward ambiguous stimuli, thus making it difficult to determine if bystanders reacted to the distressed individual or showed a delayed response to the same stimulus. Nonetheless, the directionality of the contacts and their nature strongly suggest attention toward the emotional states of conspecifics. The elephants’ behavior is therefore best classified with similar consolation responses by apes, possibly based on convergent evolution of empathic capacities.

  16. Childhood ingestions as symptoms of family distress.

    Science.gov (United States)

    Bithoney, W G; Snyder, J; Michalek, J; Newberger, E H

    1985-05-01

    Familial, child developmental, and demographic concomitants of serious ingestions in preschool children were measured in 23 hospitalized children and controls matched on age, race, and socioeconomic status. A precoded maternal interview focused on family stress, parental discipline, parental emotional history, as well as childhood temperament and social maturity. A regression analysis was performed on variables that discriminated between ingestion cases and controls. Sixteen variables from the regression equation were entered into a stepwise discriminant function analysis. Significant descriptors of ingestion victims included the following: lack of extended family low Vineland Social Maturity quotient, few maternal opportunities to escape caregiving, good health, a high frequency of physical punishment in the mother's childhood, and increased current advocacy needs. Using these six variables as a screening device, the discriminant function correctly classified 87% of the subjects as either cases or controls. These data suggest that ingestions are symptoms of familial and, especially of maternal, distress. These healthy, active, but delayed children appear to overwhelm their caregivers. PMID:3984968

  17. An Unusual Cause of Recurrent Respiratory Distress

    Directory of Open Access Journals (Sweden)

    Joshi Neha

    2010-12-01

    Full Text Available A one and a half years old boy presented with recurrent episodes of respiratory distress, accompanied by dry non spasmodic cough and characterized by appearance of a continuous stridor showing no positional variation. The child was symptomatic since early infancy. Parents also complained of inability to gain weight as compared to other siblings. There was no history of foreign body ingestion or complaints of asthma or tuberculosis in the family. General physical examination revealed tachypnea and biphasic stridor in a malnourished and stunted child in the absence of any significant lymphadenopathy or oral thrush. On systemic examination, bilaterally, stridorous sounds were auscultated. Primary investigations on the child showed minimal reflux on gastro-esophageal reflux isotope scan, a normal chest roentgenogram, negative sweat chloride test and negative serology for HIV (Human immunodeficiency virus. Echocardiography performed on the child revealed a structurally normal heart. On conducting further investigations, bronchoscopy detected a bulge in the anterior tracheal wall while barium swallow displayed indentation in the upper esophagus. The MRI (magnetic resonance imaging subsequently conducted clinched the underlying clinical condition. The MRI images are depicted below.

  18. An Unusual Cause of Recurrent Respiratory Distress

    Directory of Open Access Journals (Sweden)

    Joshi Neha

    2010-12-01

    Full Text Available A one and a half years old boy presented with recurrent episodes of respiratory distress, accompanied by dry non spasmodic cough and characterized by appearance of a continuous stridor showing no positional variation. The child was symptomatic since early infancy. Parents also complained of inability to gain weight as compared to other siblings.  There was no history of foreign body ingestion or complaints of asthma or tuberculosis in the family. General physical examination revealed tachypnea and biphasic stridor in a malnourished and stunted child in the absence of any significant lymphadenopathy or oral thrush.On systemic examination, bilaterally, stridorous sounds were auscultated. Primary investigations on the child showed minimal reflux on gastro-esophageal reflux isotope scan, a normal chest roentgenogram, negative sweat chloride test and negative serology for HIV (Human immuno­deficiency virus. Echocardiography performed on the child revealed a structurally normal heart. On conducting further investigations, bronchoscopy detected a bulge in the anterior tracheal wall while barium swallow displayed indentation in the upper esophagus. The MRI (magnetic resonance imaging subsequently conducted clinched the underlying clinical condition. The MRI images are depicted below.

  19. Medway Tunnel Road Pavement Survey Using Different Frequency GPR Antenna Systems - A Case Study

    Science.gov (United States)

    Alani, Morteza Amir; Banks, Kevin

    2015-04-01

    This presentation reports on an extensive survey carried out on a section (just outside the westbound end of the tunnel portal) of the Medway Tunnel in North Kent, UK. The Medway Tunnel provides a dual carriageway road crossing under the River Medway between Chatham and Strood. It is 725 metres long from portal to portal and consists of three sections. The appearance of repeated cracking of the road surface in this particular section of the tunnel suggested either a steady movement of the ground or possible undermining due to an underground watercourse. Ironically, the design and construction of the road had been realised to prevent any form of structural movement. It was deemed necessary to perform a Ground Penetrating Radar (GPR) survey in order to confirm underground construction details of the road in this section of the tunnel. This presentation reports on the detailed survey and the challenges encountered during the operation, which utilised four different frequency GPR systems including 2GHz, 900MHz, 600MHz and 200MHz antennas. The presentation will also describe how decisions were made to carry out supplementary surveys based on results obtained on-site (via primary data processing) and observations made during the survey. A summary of results will be presented individually for each antenna system used, as well as comparisons between each antenna system. Results will then be mapped against the design drawings available for confirmation of construction configurations. In conclusion, the presentation will demonstrate that the tunnel road pavement is not constructed as per the information provided (design drawings). Results will clearly indicate that there is no second reinforced concrete layer present in this particular section of the road pavement (contrary to what was originally believed) and will present the actual road construction in comparison with the design drawings. The results will confirm that there is no underground watercourse present in this particular section of the tunnel (at 2-3 m depth). However, it will confirm the presence of an unknown feature at a depth of 1.2m below road surface. Acknowledgement The authors would like to acknowledge the support of the COST Action TU1208 project, as well as Medway City Council's immense support in terms of expert workforce and road survey equipment in materialising this work.

  20. Distress in Spouses of Service Members with Symptoms of Combat-Related PTSD: Secondary Traumatic Stress or General Psychological Distress?

    OpenAIRE

    Renshaw, Keith D.; Allen, Elizabeth S.; Rhoades, Galena K.; Blais, Rebecca K.; Markman, Howard J.; Stanley, Scott M.

    2011-01-01

    Combat-related posttraumatic stress disorder (PTSD) is linked with elevated psychological distress in service members’/veterans’ spouses. Researchers use a variety of terms to describe this distress, and recently, secondary traumatic stress and secondary traumatic stress disorder (STS/STSD) have become increasingly commonly used. Although STS/STSD connotes a specific set of symptoms that are linked to service members’/veterans’ symptoms, researchers often use general measures of distr...

  1. The ethics of distress: toward a framework for determining the ethical acceptability of distressing health promotion advertising.

    Science.gov (United States)

    Brown, Stephen L; Whiting, Demian

    2014-04-01

    Distressing health promotion advertising involves the elicitation of negative emotion to increase the likelihood that health messages will stimulate audience members to adopt healthier behaviors. Irrespective of its effectiveness, distressing advertising risks harming audience members who do not consent to the intervention and are unable to withdraw from it. Further, the use of these approaches may increase the potential for unfairness or stigmatization toward those targeted, or be considered unacceptable by some sections of the public. We acknowledge and discuss these concerns, but, using the public health ethics literature as a guide, argue that distressing advertising can be ethically defensible if conditions of effectiveness, proportionality necessity, least infringement, and public accountability are satisfied. We do not take a broad view as to whether distressing advertising is ethical or unethical, because we see the evidence for both the effectiveness of distressing approaches and their potential to generate iatrogenic effects to be inconclusive. However, we believe it possible to use the current evidence base to make informed estimates of the likely consequences of specific message presentations. Messages can be pre-tested and monitored to identify and deal with potential problems. We discuss how advertisers can approach the problems of deciding on the appropriate intensity of ethical review, and evaluating prospective distressing advertising campaigns against the conditions outlined. PMID:24811879

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

    Science.gov (United States)

    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.

  3. Stress Analysis and Determination of Effective k-value for Rigid Pavement

    Directory of Open Access Journals (Sweden)

    Kundan Meshram

    2013-03-01

    Full Text Available EverFE is a user-friendly 3D finite-element analysis tool for simulating the response of jointed plain concrete pavement (JPCP systems to axle loads and environmental effects. EverFE is useful for both concrete pavement researchers and designers who must perform either complex nonlinear or simple linear stress analyses of JPCP.With help of this develop any type of model of rigid pavement considering practical condition thus getting more accurate and advance analysis for rigid pavement. It can also determine effective k-values for different combination of granular sub-base and dry lean concrete. A comparative study is done for two types of loading i.e. single and tandem axle. Edge and Corner stresses are also calculated for Class-AA of loading. Also calculate moment and shear force transfer by dowel bar by EverFE.

  4. 78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses

    Science.gov (United States)

    2013-05-08

    ...open-graded asphaltic concrete (OGAC), and Portland cement concrete (PCC). Prediction of future...wider range of asphaltic concrete and PCC pavements within...in how some of these new technologies and techniques could...

  5. The Effect of Cement Stabilized Subgrade on Cost of the Flexible Pavement

    Directory of Open Access Journals (Sweden)

    Baha Vural Kök

    2012-03-01

    Full Text Available The road authorities aim roads that are resistant, with less maintenance, with high traffic security, with long life and economic. It is difficult to have an economic pavement construction on the subgrade with weak bearing capacity. In this study the effect of the cement stabilization on the weak subgrade and pavement costs has been studied. For this purpose the California Bearing Ratio (CBR of a weak subgrade that has been stabilized with 4% - 16% cement have been determined. The effect of the increase in the CBR on the pavement costs has been determined thanks to MATLAB program by considering thousands of alternatives. Consequently, the optimum cement content between the decrease on the pavement costs with increase on subgrade' CBR value and the additional costs spent to increase the CBR value has been determined.

  6. Assessment of Clogging Dynamics in Permeable Pavement Systems with Time Domain Reflectometers

    Science.gov (United States)

    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...

  7. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ...BUREAU OF INDIAN AFFAIRS AND THE INDIAN RESERVATION ROADS PROGRAM Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system...shoulder information; (ii) A history of project dates and...

  8. The use of accelerometers in the pavement performance monitoring and analysis

    International Nuclear Information System (INIS)

    This study investigated the use of sensor technology to enhance the management of highway infrastructure. With the help of monitoring data, it is possible to assess the current analytical pavement analysis method, which is based on multi-layered elastic analysis, and, thus enhance the pavement design practices in use. Pavement response was measured using different sensors, installed at various depths. Most promising sensors for the continuous monitoring purposes were the accelerometers. The drawback of these sensors is that the measured quantity is acceleration, which must be converted to the deflection via mathematical integration. In this paper some issues related to the manipulation of accelerometer data is presented and discussed, in addition of the discussion of the calculated and measured pavement response.

  9. Permeable Pavement Research at NRMRL?s Urban Watershed Research Facility (Poster 2)

    Science.gov (United States)

    Assess pollutant removal efficiency of porous pavement systems with regard to parking lot runoff. Bench-scale study will examine: Discharge volume Flow rate Total suspended solids (TSS) of influent vs. effluent Use of a geotextile permeable filter fabric...

  10. Integration and road tests of a self-sensing CNT concrete pavement system for traffic detection

    International Nuclear Information System (INIS)

    In this paper, a self-sensing carbon nanotube (CNT) concrete pavement system for traffic detection is proposed and tested in a roadway. Pre-cast and cast-in-place self-sensing CNT concrete sensors were simultaneously integrated into a controlled pavement test section at the Minnesota Road Research Facility (MnROAD), USA. Road tests of the system were conducted by using an MnROAD five-axle semi-trailer tractor truck and a van, respectively, both in the winter and summer. Test results show that the proposed self-sensing pavement system can accurately detect the passing of different vehicles under different vehicular speeds and test environments. These findings indicate that the developed self-sensing CNT concrete pavement system can achieve real-time vehicle flow detection with a high detection rate and a low false-alarm rate. (paper)

  11. Theoretical analysis of piezoelectric energy harvesting from traffic induced deformation of pavements

    International Nuclear Information System (INIS)

    The problem of energy harvesting using piezoelectric transducers for pavement system applications is formulated with a focus on moving vehicle excitations. The pavement behavior is described by an infinite Bernoulli–Euler beam subjected to a moving line load and resting on a Winkler foundation. A closed-form dynamic response of the pavement is determined by a Fourier transform and the residue theorem. The voltage and power outputs of the piezoelectric harvester embedded in the pavements are then obtained by the direct piezoelectric effect. A comprehensive parametric study is conducted to show the effect of damping, the Winkler modulus, and the velocity of moving vehicles on the voltage and power output of the piezoelectric harvester. It is found that the output increases sharply when the velocity of the vehicle is close to the so-called critical velocity. (paper)

  12. The Influence of Waste Carpet on the Structural Soil Characteristics in Pavement Granular Layer

    Directory of Open Access Journals (Sweden)

    Mohammad M. Khabiri

    2011-07-01

    Full Text Available Solid waste materials can be left out of environment in different ways or can be used again. As an example of waste fiber materials is the fibers reselling from producing carpet which are made in Iran in largest quantity. These materials are added to soil and granular materials and improve their various properties as compressive and tensile strengths. In present study, the result of previous researches are collected and presented, then, they are used to analyses the effect of using from waste materials in subgrade on highway pavement performance. By using analytical software and results of testing, tensile strain under asphalt layer and compressive strain on subgrade of pavement containing these materials are calculated and after that they are compared together. Next the allowable frequencies of loading for different pavement models are calculated by using existing formula. The results indicate that adding 1.5% of waste fiber to pavement subgrade increases the allowable frequency of loading to 15%.

  13. Development of Knowledge-Based Expert System for Flexible Pavement Design

    Directory of Open Access Journals (Sweden)

    Deprizon

    2009-01-01

    Full Text Available In this study, the knowledge-based expert system approach was used to design a programmer using shell expert system of KAPPA PC Version 2.4 that is object oriented and displaying higher graphic resolutions. The flexible pavement design based on the accumulation of knowledge from several experts, books and journals results in a modular approach. Normally, the process of flexible pavement design is done by experts. The process was computerized and apply artificial intelligent that is a new technology in providing a system that can design and give the suggestion for user to choices the best and economy of the thickness of pavement layers. The expert system was tested using several design calculation samples. From the test, the success is 100% for pavement design. The expert system has revealed satisfactorily findings in a faster layers design.

  14. Sensitivity of the LCA allocation procedure for BFS recycled into pavement structures

    OpenAIRE

    Sayagh, Shahinaz; Ventura, Anne; Hoang, Tung; Francois, Denis; Jullien, Agnès

    2010-01-01

    The purpose of this paper is twofold : to investigate the problems involved when performing an environmental assessment of various pavements structures and to establish the method applied to solutions proposed by official French guidelines. This assessment will be performed by employing the life cycle assessment (LCA) methodology specifically adapted to road pavements through a parametric environmental evaluation tool developed by LCPC: ERM (elementary road modulus). The paper will also detai...

  15. An approach for the definition of construction and maintenance strategies for flexible pavements

    OpenAIRE

    Sousa, Jorge B.; Pais, Jorge C.; Eckmann, Bernard

    1998-01-01

    Design, Build, Finance and Operate contracts to develop a road network require a re-evaluation of the strategic decisions towards the design and maintenance strategies of flexible pavements. Probabilistic analysis, based on the variability of pavement material properties and layer thickness as well as on traffic variability is required and needed as a cost effective basis for the many possible design and maintenance strategies. The NOAH software was used to combine hundreds of possibl...

  16. Utilizationof Hypo Sludge by Eco-Efficient Development of Rigid Pavement in Rural Roads

    OpenAIRE

    Prof. Jayeshkumar Pitroda1 , Dr. L.B.Zala2 , Dr.F.S.Umrigar

    2013-01-01

    The paperproducing industry generates various wastes coming out from the various processes. From the preliminary waste named as hypo sludge, due to its low calcium is taken out to replace the cement in concrete. Major initiatives are needed in India to use these large volumes in construction industry especially in rigid pavement construction and other infrastructure projects. Moreover Use of Hypo Sludge in construction of rigid pavement will improve transportation functionality and ecological...

  17. New-Fangled Approach to Predict the Behaviour of Composite Sandwich Pavements

    OpenAIRE

    A K, Shaul Sharafna

    2011-01-01

    The significance of this research lies in the reduction of cost of construction of roads by arriving at an economically feasible pavement. This is accomplished by studying the response of thick composite sandwich plate, supported continuously, for the cyclic loading condition at various stress ratios and is compared with plain slabs placed on similar support condition. A conceptual pavement model was examined using lean cement concrete as the sandwiched material. The behaviour of the plain an...

  18. Assessing artificial neural network performance in estimating the layer properties of pavements

    OpenAIRE

    Gloria Inés Beltran; Miguel Pedro Romo

    2014-01-01

    A major concern in assessing the structural condition of existing flexible pavements is the estimation of the mechanical properties of constituent layers, which is useful for the design and decision-making process in road management systems. This parameter identification problem is truly complex due to the large number of variables involved in pavement behavior. To this end, non-conventional adaptive or approximate solutions via Artificial Neural Networks – ANNs – are considered to proper...

  19. Possible method of determining structural number for flexible pavements with the falling weight deflectometer

    OpenAIRE

    Schnoor, H.; Horak, Emile

    2012-01-01

    The paper describes a procedure where the condition of flexible pavements is investigated with the help of non-destructive tests such as the Falling Weight Deflectometer (FWD). The condition or indication of structural strength is expressed in terms of the Structural Number (SN). An existing method of determining the Structural Number was used as benchmark with data from a recent detailed pavement investigation. The benchmark SN determination also makes use of the Dynamic Cone Penetrometer (D...

  20. Mechanistic modelling of weak interlayers in flexible and semi-flexible road pavements: Part 2

    OpenAIRE

    Beer, M.; Maina, J. W.; Netterberg, F.

    2012-01-01

    This paper (Part 2 of a two-part set of papers) discusses models and illustrates the adverse effects of weak layers, interlayers, laminations and/or weak interfaces in flexible and semi-flexible pavements, also incorporating lightly cemented layers. The modelling is based on mechanistic analyses for pavement design and evaluation. In Part 1, the effects of these relatively weak layers, interlayers, laminations and/or weak interfaces were discussed. It was shown that methodologies are availabl...

  1. METHODS FOR DETERMINING THE OPTIMAL SOLUTION FOR THE REHABILITATION OF CEMENT CONCRETE ROAD PAVEMENTS

    OpenAIRE

    Gavris, Ovidiu

    2012-01-01

    Rehabilitation (restoration) of cement concrete pavements raises a number of problems for road engineers because of the rigidity of the structure. Solutions used generally fall into two categories: one which implies milling the concrete tiles (recycling them) and another solution which involves covering the existing pavement with asphalt road systems that behave well under traffic. This article aims to provide a multi-criteria analysis method regarding the choice of intervention in such secto...

  2. Trade off between costs and environmental effects of weed control on pavements

    OpenAIRE

    Kempenaar, C.; Lotz, L. A. P.; Horst, C. L. M.; Beltman, W. H. J.; Leemans, K. J. M.; Bannink, A. D.

    2007-01-01

    An actor-participative project on sustainable weed control on pavements was started in 2000 in the Netherlands. The aim of the project was to develop a new concept of weed management that provides cost-effective and environmentally sound weed control. Early in 2002, practical guidelines were drawn up in support of decision making by managers of pavements, and weed control contractors. The guidelines are focused mainly on reduction of herbicide use and emission thereof. The new concept was tes...

  3. Life Cycle Assessment Applied to Road Pavements: An Analysis of Method and Results Relevancy

    OpenAIRE

    Ventura, Anne; Jullien, Agne?s

    2009-01-01

    The use of Life Cycle Assessment (LCA) for evaluating environmental performances of products is becoming usual in Europe. In that context, many studies have been published aiming at comparing different technologies for construction and maintenance of pavements. The paper examines and compares studies performing LCA of pavements, with the aim of pulling out important parameters that can explain different results. The first step of this paper consists of selecting some of the available studies ...

  4. Estimation of carrying capacity of slag and gravel forest road pavements

    OpenAIRE

    Grzegorz Trzcinski; Sergiusz Kaczmarzyk

    2006-01-01

    The objective of the study was to estimate the carrying capacity of forest roads with slag and gravel pavements. Deformation module and elastic deflection were used as characteristic parameters of road carrying capacity. There were 9 tested sections divided into set groups. All investigated sections were measured using VSS plate (29 measurements) and deflectometer (53 measurements). Averaged results of the measurements of specific pavements were introduced in the analysis. The present study p...

  5. Test of Microstructur Permeable Asphalt Pavement Used Domato Stone (Quarsite Dolomite) As Course Agregate for Surface Layer of Road Pavement

    OpenAIRE

    Firdaus Chairuddin; Wihardi Tjaronge

    2014-01-01

    The experiment works was dividing into two phases, for phase one was developed to investigate the properties of aggregates and straight asphalt qualities. The experiment work for phase two was developed to design the porous asphalt mix. In this phase Japan’s method and Binamarga’s method was used to define optimum asphalt content. In this phase, has result cantabro loss weight 77.10 for asphalt quality 3% and loss weight 9.70 for asphalt quality 5%. asphalt flow down, air v...

  6. Test of Microstructur Permeable Asphalt Pavement Used Domato Stone (Quarsite Dolomite As Course Agregate for Surface Layer of Road Pavement

    Directory of Open Access Journals (Sweden)

    Firdaus Chairuddin

    2014-06-01

    Full Text Available The experiment works was dividing into two phases, for phase one was developed to investigate the properties of aggregates and straight asphalt qualities. The experiment work for phase two was developed to design the porous asphalt mix. In this phase Japan’s method and Binamarga’s method was used to define optimum asphalt content. In this phase, has result cantabro loss weight 77.10 for asphalt quality 3% and loss weight 9.70 for asphalt quality 5%. asphalt flow down, air void and density values. The experiment work for phase two was developed to investigate the qualities of porous asphalt. In this phase, wheel tracking machine test was used to investigate the dynamic stability of mixes.

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

    Science.gov (United States)

    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. Thermal behavior of an asphalt pavement in the laboratory and in the parking lot.

    Science.gov (United States)

    Martinkauppi, J B; Mäkiranta, A; Kiijärvi, J; Hiltunen, E

    2015-01-01

    The urban, constructed areas are full of buildings and different kinds of pavements and have a noticeable lack of trees and flora. These areas are accumulating the heat from the Sun, people, vehicles, and constructions. One interesting heat collector is the asphalt pavement. How does the heat transfer to different layers under the pavement or does it? What are the temperatures under the pavement in Finland where the winter can be pretty hard? How can those temperatures be measured accurately? These are the main questions this paper gives the preliminary answers to. First the thermal behavior of asphalt and the layers beneath are researched in the laboratory and then the measurement field is bored and dug in the parking in the Western coast of Finland, 63°5'45''?N. Distributed temperature sensing method was found to be a good choice for temperature measurements. Thermal behavior of pavement has been monitored in different layers and the preliminary results have been published here. The goal of this research is to assess the applicability of asphalt pavements for heat energy collection. PMID:25861679

  9. Lead and zinc removal with storage period in porous asphalt pavement

    Scientific Electronic Library Online (English)

    Yao, Zhao; Chen, Zhao.

    2014-01-01

    Full Text Available Porous asphalt pavements have been used as an effective technique to overcome road runoff challenges, and to improve efficiency of rainwater utilisation in urban areas. Using porous asphalt pavements with reservoir storage and harvesting facilities is an important consideration for the future. This [...] study monitored changes in water quality indicators, such as pH, conductivity, and concentrations of lead and zinc, for water stored in porous asphalt pavement models with basalt-, limestone- and 'basalt+limestone'-filled reservoir structures. The research discusses findings over a 696-h storage period following artificial rainfall. Total lead and zinc concentrations were remarkably reduced throughout the initial flush, showing, on average, reductions of 90% and 80.5%, respectively. This pattern was consistent throughout the storage period, producing average reductions in lead and zinc of 99.98% and 79%, respectively, over 696 h. Conductivity and pH levels increased in all pavement models after the 696-h storage. The results obtained confirmed the potential of using porous asphalt pavements with reservoir structures to remove heavy metals from road runoff. This can be applied to future research on the removal mechanisms of porous asphalt pavements in relation to heavy metals in road runoff.

  10. Prediction of Airport Flexible Pavement Critical Responses from Non-destructive Test Data Using ANN-based Structural Models

    OpenAIRE

    Kasthurirangan Gopalakrishnan

    2006-01-01

    This study describes the development of Artificial Neural Network (ANN) based pavement response prediction models for rapid structural analysis of airport flexible pavements based on Non-destructive Test (NDT) data. A finite element based pavement structural model, which can accommodate stress-sensitive geomaterial stiffness models, was used to generate the ANN training and testing dataset. The goal was to establish ANN models for predicting critical responses (stresses and strains) from rout...

  11. Monitoring of Artificial Defects within a Pavement Structure with a NDT Method Based on a Mechanical Impact

    OpenAIRE

    Simonin, Jean-Michel; Hornych, Pierre

    2014-01-01

    This paper presents a non-destructive testing (NDT) method used to monitor a pavement structure which contains artificial defects. A 25 m long pavement section has been built on the full scale accelerated pavement testing facility of IFSTTAR in Nantes. The structure is made of two bituminous layers (8 cm thick base layer, and 6 cm thick wearing course), over a granular subbase. Several types of defects have been included at the interface between the two asphalt layers (figure 1). Rectangular ...

  12. Traf?c noise abatement : how different pavements, vehicle speeds and traf?c densities affect annoyance levels

    OpenAIRE

    Freitas, Elisabete F.; Mendonc?a, Catarina; Santos, Jorge A.; Murteira, Carla; Ferreira, Joa?o

    2012-01-01

    In this paper, annoyance ratings from traf?c noise recorded on cobblestones, dense asphalt, and open asphalt rubber pavements are assessed with regard to car speeds and traf?c den- sities. It was found that cobblestones pavements are the most annoying; also while open asphalt rubber pavement imposes less annoyance than dense asphalt it is not signi?cantly different. Higher car speeds always lead to greater annoyance, as does higher traf?c densi- ties. LAeq and LAma...

  13. A TECHNIQUE OF ESTIMATION OF TECHNICAL CONDITION OF RIGID AIRFIELD PAVEMENTS IN THE CONTEXT OF RISK THEORY

    OpenAIRE

    Popov, A. N.; Shashkov, I. G.; Kozlov, A. V.

    2012-01-01

    Problem statement. To provide for safe takeoff and landing of modern aviation complexes, specialattention is given to technical condition of artificial pavements of runways which can be serviceableor faulty, efficient or limiting. Available standard methods of an expeditious estimation of an operational-technical condition of airfield pavements are based on general principles of defect graduationand of definition of integrated total generalized indicator of pavement condition and often yield ...

  14. Article title misstates the role of pavement sealers.

    Science.gov (United States)

    O'Reilly, Kirk

    2014-08-01

    The claim made in the title of Witter et al. (2014) "Coal-tar-based sealcoated pavement: A major PAH source to urban stream sediments" is not supported by the data presented. The author's use of Pearson correlation coefficients is insufficient to indicate causation. The application of spatial analysis and principle component analysis did not include sealer specific inputs, so provides no basis for the claim. To test the hypothesis that sealers are a source of PAHs in the stream studied, EPA's Chemical Mass Balance (CMB) source evaluation model was applied to Witter's sediment data. CMB found an excellent fit (R(2) > 0.999) between measured and modeled PAH concentrations when sealers were not included as a potential source. This finding does not support Witter et al. (2014) claim that sealers are a major source of PAHs. PMID:24373812

  15. Fatigue Investigation of the Interface Shear Performance in Asphalt Pavement

    Directory of Open Access Journals (Sweden)

    Cristina Tozzo

    2014-02-01

    Full Text Available This paper shows the interlayer fatigue performance evaluated by the Sapienza shear testing machine. The tests can be performed by placing double layer specimens in several inclinations, in order to reproduce a variety of expected ratios between the normal and the shear stress. The machine manages loads with any kind of waveform and is particularly able to simulate the stress trends expected in field in points located just outside the wheel path. In this experimentation, the machine applies a triangular waveform load computed by a linear elastic multilayer program at the depth of the first pavement interface. A fatigue law is estimated considering the number of repetitions that causes the interface failure. A linear regression in the log-log graph suitably fits the experimental results for the analyzed conditions of temperature and interface type.

  16. Road Performance of Fiber Reinforced Asphalt Concrete Bridge Deck Pavement

    Directory of Open Access Journals (Sweden)

    Xiu Liu

    2013-01-01

    Full Text Available As the problem of asphalt concrete bridge deck pavement is becoming more and more serious, how to improve its road performance has become the focus of the study. Considering fiber is widely used in road engineering, wheel tracking test, flexural test, immersion marshall test and freeze-thaw splitting test were carried out to study road performance of asphalt mixture with different fiber contents, analyzing the function mechanism of fiber reinforced asphalt concrete. The test results show that polyester fiber can improve high-temperature stability, low-temperature crack resistance property and water stability of asphalt concrete and road performance improves with the fiber content increasing in a certain range.

  17. Addressing appearance-related distress across clinical conditions.

    Science.gov (United States)

    Bessell, Alyson; Dures, Emma; Semple, Cherith; Jackson, Sue

    Evidence is accumulating about the nature and prevalence of appearance-related distress across a variety of clinical populations. Health professionals working with specific patient groups are often aware of these difficulties and their detrimental effect on quality of life and wellbeing. However, many health professionals lack knowledge and skills on how to support patients, either within the team or via referral to relevant service providers who have expertise in managing appearance-related distress. This is mainly owing to a lack of information about screening, assessment measures and available interventions. The aim of this article is to consider how health professionals can support patients who experience distress as a result of living with a long-term physical health condition that has altered their appearance. This article summarises the challenges for patients and health professionals surrounding body image, altered appearance and associated distress. Gaps in relation to screening measures, differing types of intervention, appearance-related skills training for healthcare teams, care pathways and access to services are identified. A summary of the limited range of interventions currently available has been mapped onto a stepped model of care, ranging from self-help to intensive therapies. Finally, readers are pointed to helpful resources for understanding, identifying, addressing and signposting patients with appearance-related distress. PMID:23123892

  18. Emotional distress in women presenting for breast imaging

    International Nuclear Information System (INIS)

    The aim of this study was to assess anxiety and depression in a sample of women presenting for imaging of breast following a clinical referral. Emotional distress in the women was also assessed in relation to demographic factors, reason for referral, presence for breast symptoms, type of imaging procedure performed and self-reported pain and discomfort during imaging. The study comprised 167 patients. The Hopkins Symptom Checklist-25 (HSCL-25) and a discomfort rating scale were used to assess emotional distress and discomfort or pain experienced during the imaging. While less than 10% of all subjects scored above psychiatric cut-off points for anxiety and depression, 25% and 20% reported significant distress associated with anxiety and depression symptoms respectively. Education alone was associated with higher anxiety scores, while the presence of breast symptoms significantly increased depression scores and reports of specific nonsomatic symptoms of depression. Higher anxiety and depression scores were also associated with pain experienced during the imaging procedure. Emotional distress may negatively impact women's experience of breast imaging. Screening for emotional distress is important within the context of breast imaging. (author)

  19. Financial Distress Prediction of Iranian Companies Using Data Mining Techniques

    Directory of Open Access Journals (Sweden)

    Moradi Mahdi

    2013-01-01

    Full Text Available Decision-making problems in the area of financial status evaluation are considered very important. Making incorrect decisions in firms is very likely to cause financial crises and distress. Predicting financial distress of factories and manufacturing companies is the desire of managers and investors, auditors, financial analysts, governmental officials, employees. Therefore, the current study aims to predict financial distress of Iranian Companies. The current study applies support vector data description (SVDD to the financial distress prediction problem in an attempt to suggest a new model with better explanatory power and stability. To serve this purpose, we use a grid-search technique using 3-fold cross-validation to find out the optimal parameter values of kernel function of SVDD. To evaluate the prediction accuracy of SVDD, we compare its performance with fuzzy c-means (FCM.The experiment results show that SVDD outperforms the other method in years before financial distress occurrence. The data used in this research were obtained from Iran Stock Market and Accounting Research Database. According to the data between 2000 and 2009, 70 pairs of companies listed in Tehran Stock Exchange are selected as initial data set.

  20. Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements

    DEFF Research Database (Denmark)

    Jensen, Kaj Sand; Hammer, Kathrine

    2012-01-01

    Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species richness, and evaluated duration of plant activity during desiccation as a function of ground area, for a large collection of moss cushions. We found that lower evaporation and higher water storage contributed equally to extending the desiccation period with increasing cushion size. Evaporation rates declined by the -0.36 power of cushion diameter, and were not significantly different from -0.50 for the square root function previously predicted for the increasing thickness of the boundary layer, with greater linear dimensions for smooth flat objects at low wind velocities. Size dependence vanished under stagnant conditions. One moss species was added to the species pool for every nine-fold increase in cushion area. Vascular plants were absent from the smallest cushions, whereas one or two species, on average, appeared in 375- and 8,500-cm(2) cushions with water available for 6 and 10 days during desiccation. Phosphorus concentrations increased stepwise and four-fold from detritus to surface mosses and to vascular plants, and all three pools increased with cushion size. We conclude that cushion mosses and cushion size play a critical role in this resource-limited limestone environment by offering an oasis of improved water and nutrient supply to colonization and growth of plants.

  1. Stresses, strains, and displacements in a poroelastic layered pavement model subject to a moving load

    International Nuclear Information System (INIS)

    The response of a layered poroelastic halfspace to a progressing normally distributed load applied at the surface is evaluated for the case in which the constant velocity of the moving load is less than that of the elastic waves in each layer. It is assumed that a steady state exists with respect to the coordinate axes attached to a moving load. A three-dimensional problem for Biot's consolidated equations is then solved by taking Fourier transforms in the horizontal directions to evaluate stresses and displacements at any point in the medium. The analysis is illustrated by numerical examples using an algorithm based on one previously developed to calculate the response to a static load for axisymmetric poroelastic layers. To reduce the amount of computation, attention is restricted to a two-dimensional problem in which the load extends infinitely in the transverse direction. Results are presented for two and three-layered pavement models composed of concrete and gravel over a clay subbase responding to moving traffic, but the method is applicable to any number of layers. The effect of varying the velocity of the load and layer properties is observed

  2. Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements.

    Science.gov (United States)

    Sand-Jensen, Kaj; Hammer, Kathrine Jul

    2012-10-01

    Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species richness, and evaluated duration of plant activity during desiccation as a function of ground area, for a large collection of moss cushions. We found that lower evaporation and higher water storage contributed equally to extending the desiccation period with increasing cushion size. Evaporation rates declined by the -0.36 power of cushion diameter, and were not significantly different from -0.50 for the square root function previously predicted for the increasing thickness of the boundary layer, with greater linear dimensions for smooth flat objects at low wind velocities. Size dependence vanished under stagnant conditions. One moss species was added to the species pool for every nine-fold increase in cushion area. Vascular plants were absent from the smallest cushions, whereas one or two species, on average, appeared in 375- and 8,500-cm(2) cushions with water available for 6 and 10 days during desiccation. Phosphorus concentrations increased stepwise and four-fold from detritus to surface mosses and to vascular plants, and all three pools increased with cushion size. We conclude that cushion mosses and cushion size play a critical role in this resource-limited limestone environment by offering an oasis of improved water and nutrient supply to colonization and growth of plants. PMID:22481304

  3. A Simple Field Test to Evaluate the Maintenance Requirements of Permeable Interlocking Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Terry Lucke

    2015-05-01

    Full Text Available Adequate infiltration through Permeable Interlocking Concrete Pavements (PICPs is critical to their hydraulic and stormwater treatment performance. Infiltration is affected by clogging caused by the trapping of fines in the PICP surface, which, over time, reduces treatment performance. Clogging can be reduced by periodic maintenance such as vacuum sweeping and/or pressure washing. Maintenance requirements can be indicated by measuring reduced infiltration rates. This paper compared infiltration results using the standard test (C1781M-14a with the results of a new stormwater infiltration field test (SWIFT developed in Australia to evaluate the maintenance requirements of PICPs. A strong correlation (Pearson’s r = ?0.714 was found between results using the two methods. This study found that the SWIFT was a reliable method for estimating the degree of clogging of PICPs while successfully overcoming some of the problems with the more technical existing test methodology such as horizontal water leakage (use of sealant, unrealistic pressure heads, speed of test, and portability. The SWIFT test is a simple, fast and inexpensive way for asset managers and local government employees to quickly assess the maintenance requirements of PICP installations in the field.

  4. Experimental Analysis of Natural Gravel Covering as Cool Roofing and Cool Pavement

    Directory of Open Access Journals (Sweden)

    Anna Laura Pisello

    2014-07-01

    Full Text Available Passive solutions for building energy efficiency represent an interesting research focus nowadays. In particular, natural materials are widely investigated for their potential intrinsic high thermal energy and environmental performance. In this view, natural stones represent a promising solution as building envelope covering and urban pavement. This paper concerns the experimental characterization of several low-cost and local gravel coverings for roofs and urban paving, properly selected for their natural high albedo characteristics. To this aim, the in-field albedo of gravel samples is measured with varying grain size. These in-field measurements are compared to in-lab measurements of solar reflectance and thermal emissivity. The analysis shows a significant variation of the albedo with varying grain size. Both in-lab and in-field measurements agree that the stones with the finest grain size, i.e., fine sand, have the best optic-thermal performance in terms of solar reflectance (62%. This feature results in the reduction of the surface temperature when exposed to solar radiation. Moreover, a natural mixed stone is compared to the high reflectance stone, demonstrating that the chosen stone presents an intrinsic “cool” behavior. Therefore, this natural, low-cost, durable and sustainable material could be successfully considered as a natural cool roof or cool paving solution.

  5. Camiones de alto tonelaje y su impacto en ciclo de vida de pavimentos asfálticos / Heavy load trucks and its impact in life cycle of asphalt pavements

    Scientific Electronic Library Online (English)

    R, Díaz; T, Echaveguren; S, Vargas-Tejeda.

    2012-04-01

    Full Text Available En los últimos años se inició el debate sobre la factibilidad técnico-económica de introducir en la flota de transporte de carga configuraciones de alto tonelaje (CAT). Estas configuraciones superan el peso bruto total máximo de 45 t permitido en Chile, distribuyendo la carga sobre un mayor número d [...] e ejes. En Chile no existe experiencia en el uso de este tipo de configuraciones de carga, por lo que es prudente y necesario estudiar el impacto global que tendrían en el sistema de transporte interurbano si se implementan. En este trabajo se analiza en particular el impacto sobre los pavimentos asfálticos. Utilizando un enfoque mecanicista-empírico, se comparó el impacto en el ciclo de vida producido por CAT del tipo bitrén corto y largo, y configuraciones tradicionales del tipo camión-remolque y tracto-semirremolque. En la evaluación se consideraron diferentes estructuras de pavimento, condiciones climáticas y niveles de tránsito solicitante, representativos de la Región del Biobío. La evaluación mecanicista-empírica se realizó utilizando el método de diseño de pavimentos mecanicista francés Alize-LCPC, y los modelos de deterioro desarrollados por el Asphalt Institute. Para comparar distintos métodos de evaluación y modelos de deterioro, el ciclo de vida fue evaluado utilizando la Ley de Miner implementada en la guía de diseño MEPDG de Estados Unidos. Los resultados mostraron que el camión-remolque produce mayor daño en el pavimento, mientras que el tracto-semirremolque es el que produce menor daño, ambos con 45 t de peso bruto total. El bitrén largo de 75 t produce un impacto estructural levemente menor que el bitrén corto de 61 t. Sin embargo, se encontró evidencia teórica de que las CAT producen mayor ahuellamiento superficial en forma proporcional al peso bruto total. Abstract in english In recent years a discussion of the technical-economic feasibility of introduce the heavy load trucks (CAT) in goods transport fleet was started. This truck configurations overpass the maximum gross weight of 45 t permitted in Chile. In Chile there not exist experience of using this type of trucks, [...] whence is relevant to study the global impact of it over the interurban transport system. This paper discusses the impact of heavy load trucks over asphalt pavements. Using a mechanistic-empirical framework, the impact of two types of CAT, long and short bitrén, and a one and two units 45 tons trucks were compared along the life-cycle of the pavement. Assessment considers different pavement configurations, weather conditions and traffic levels, typical of the Bio Bio region. The mechanistic-empirical assessment was performed using the Alize-LCPC pavement design tool and the deterioration models of the Asphalt Institute. For comparing deteriorations, the life-cycle was assessed using the Miner Law implemented in the Mechanist-Empirical Pavement Design Guide, MEPDG. Results show that the one unit truck induces the greater damage over the pavement and that the two unit truck induces the lower damage. The long bitren (75 tons) induce a slightly lower impact than the short bitren. However it was found evidence that the CAT induce the greater rutting in the pavement surface, which increases linearly if the gross weight of the truck increases.

  6. Discrimination and psychological distress among recently released male prisoners.

    Science.gov (United States)

    Turney, Kristin; Lee, Hedwig; Comfort, Megan

    2013-11-01

    Though theoretical perspectives suggest experiences of stigma and discrimination after release may be one pathway through which incarceration leads to poor mental health, little research considers the relationship between discrimination and mental health among former inmates. In this article, data from a sample of men recently released from prison to Oakland or San Francisco, California (N = 172), are used to consider how criminal record discrimination and racial/ethnic discrimination are independently and cumulatively associated with psychological distress. Results indicate that (a) the frequency of criminal record discrimination and racial/ethnic discrimination are similar; (b) both forms of discrimination are independently, negatively associated with psychological distress; and (c) the level of racial/ethnic discrimination does not alter the association between criminal record discrimination and psychological distress. The results highlight that criminal record discrimination is an important social stressor with negative implications for the mental health of previously incarcerated individuals. PMID:23553444

  7. Acute respiratory distress syndrome: epidemiology and management approaches

    Directory of Open Access Journals (Sweden)

    Walkey AJ

    2012-07-01

    Full Text Available Allan J Walkey,1 Ross Summer,1 Vu Ho,1 Philip Alkana21The Pulmonary Center, Boston University School of Medicine, Boston, MA, USA; 2Asthma Research Center, Brigham and Women's Hospital, Boston, MA, USAAbstract: Acute lung injury and the more severe acute respiratory distress syndrome represent a spectrum of lung disease characterized by the sudden onset of inflammatory pulmonary edema secondary to myriad local or systemic insults. The present article provides a review of current evidence in the epidemiology and treatment of acute lung injury and acute respiratory distress syndrome, with a focus on significant knowledge gaps that may be addressed through epidemiologic methods.Keywords: acute lung injury, acute respiratory distress syndrome, review, epidemiology

  8. Inmarsat distress and safety services - Present and future

    Science.gov (United States)

    Ivanov, K.

    1982-09-01

    Currently, the International Maritime Satellite Organization (Inmarsat) system of satellite communications with the Standard-A ship earth station is an important means for ship-to-shore and shore-to-ship alerting, search and rescue coordinating and on-scene communications. This capacity will be enhanced by new features and services. Emergency Position-Indicating Radio Beacons (EPIRB's) will automatically transmit a distress message containing vessel identity, position coordinates, course and speed as well as the nature of the distress. The proposed Standard-C terminal would provide a small ship earth station capable of transmitting low speed digital telex-like messages under adverse conditions. The automated collection of data on weather, ship position and performance transmitted by on-board navigation instruments and remote sensors is also feasible. These systems could all play an important role in the Future Global Maritime Distress and Safety System that is expected to begin functioning around 1990.

  9. Patterns of gender equality at workplaces and psychological distress.

    Science.gov (United States)

    Elwér, Sofia; Harryson, Lisa; Bolin, Malin; Hammarström, Anne

    2013-01-01

    Research in the field of occupational health often uses a risk factor approach which has been criticized by feminist researchers for not considering the combination of many different variables that are at play simultaneously. To overcome this shortcoming this study aims to identify patterns of gender equality at workplaces and to investigate how these patterns are associated with psychological distress. Questionnaire data from the Northern Swedish Cohort (n?=?715) have been analysed and supplemented with register data about the participants' workplaces. The register data were used to create gender equality indicators of women/men ratios of number of employees, educational level, salary and parental leave. Cluster analysis was used to identify patterns of gender equality at the workplaces. Differences in psychological distress between the clusters were analysed by chi-square test and logistic regression analyses, adjusting for individual socio-demographics and previous psychological distress. The cluster analysis resulted in six distinctive clusters with different patterns of gender equality at the workplaces that were associated to psychological distress for women but not for men. For women the highest odds of psychological distress was found on traditionally gender unequal workplaces. The lowest overall occurrence of psychological distress as well as same occurrence for women and men was found on the most gender equal workplaces. The results from this study support the convergence hypothesis as gender equality at the workplace does not only relate to better mental health for women, but also more similar occurrence of mental ill-health between women and men. This study highlights the importance of utilizing a multidimensional view of gender equality to understand its association to health outcomes. Health policies need to consider gender equality at the workplace level as a social determinant of health that is of importance for reducing differences in health outcomes for women and men. PMID:23326404

  10. Psychological distress in Japanese men with localized prostate cancer

    International Nuclear Information System (INIS)

    The objective of this study was to investigate: the level of psychological distress; and the relationships between the level of psychological distress and general or disease-specific HRQOL of Japanese men with localized prostate cancer following surgery or radiotherapy. The study was a retrospective cross-sectional survey of 253 men with localized prostate cancer treated with radical prostatectomy and 87 with external beam radiotherapy were collected. The measures used four questionnaires including: the Medical Outcomes Study 36-Item Health Survey; The University of California, Los Angeles Prostate Cancer Index; International Prostate Symptom Score; and Hospital Anxiety and Depression Scale (HADS). Mean anxiety and depression scores were 4.0 and 4.7, respectively (standard deviation, 3.3 and 3.7). On the anxiety section of HADS, 291 patients (85%) scored 7 points or less; and on the depression scale, 183 (54%) patients scored 4 points or less. Those 'cases' (HADS total, >10) with psychological distress scored lower in all domains of the general and disease related health-related quality of life (HRQOL) than the 'non-cases' (HADS total, ?10) except for sexual domains. Logistic regression modeling suggested that the men who tended to experience moderate to high distress suffered from worse urinary and bowel symptoms. Most patients who underwent radical prostatectomy or external beam radiotherapy for localized prostate cancer experienced low levels of psychological diserienced low levels of psychological distress after treatment. However, men who were experiencing urinary and bowel symptoms tended to suffer from moderate to higher distress compared with men reporting no or fewer such symptoms. (author)

  11. [The Life Style Index: correlations with psychological distress and hostility].

    Science.gov (United States)

    Hyphantis, T; Floros, G D; Goulia, P; Iconomou, G; Assimakopoulos, K

    2011-01-01

    The Life Style Index (LSI) was designed to assess defense mechanisms, assuming that their use is related to specific emotional states and diagnostic concepts. Aiming to further investigate the psychometric properties of the Greek version of the LSI, the aim of the present study was to investigate the relationship of specific defense mechanisms with dimensions of psychological distress and hostility features in three different populations. The sample comprised 1261 adults (410 healthy participants, 723 medical patients and 128 psychiatric patients). Along with defense mechanisms (LSI), Psychological Distress (General Health Questionnaire, GHQ-28) and Hostility features (Hostility and Direction of Hostility Questionnaire, HDHQ) were also assessed. The results showed that increased psychological distress is related with increased use of all defenses except Denial, with which psychological distress is negatively associated. Regression is constantly related with psychological distress and differentiates psychiatric patients from the other groups of participants, while Compensation and Reaction Formation are related to depressive symptomatology. In medical patients, Repression was found to increase the physical dimension of psychological distress and the social dysfunction. On the contrary,Denial was negatively associated with these dimensions of psychological distress. In the psychiatric patient and healthy participant samples, Projection plays the most detrimental role. Regarding hostility and direction of hostility, those who were found to introvert their hostility presented with higher scores in Denial, indicating that they possibly 'deny' their hostility, and the degree of the Denial was found to be negatively associated with the degree of Introverted Hostility. Those who directed their hostility towards the others, presented with higher rates of Projection, while neither Denial nor Reaction Formation seemed sufficient enough to temper the degree of Extroverted Hostility. In conclusion,the present results strengthen further the validity of the Greek version of the LSI and provide additional evidence about the relation of defence mechanisms with dimensions of psychological distress and the direction of hostility in different populations, indicating that the empirical assessment of defense mechanisms can contribute significantly in the study of the factors that mediate or moderate the course or the outcome of medical or psychiatric disorders. PMID:21971196

  12. Perceived Discrimination and Psychological Distress of Myanmar Refugees in Malaysia

    Directory of Open Access Journals (Sweden)

    Sew Kim Low

    2014-05-01

    Full Text Available The purpose of this research is to explore the psychological distress and discrimination experienced by refugees from Myanmar in Malaysia. A narrative inquiry approach and an in depth interview were chosen to get in touch with the social world of the refugees. Bronfenbrenner’s (1979 ecological theory was used to examine the psychological distress of the participants in their social context. The findings revealed the social, economical and psychological discrimination experienced by these refugees while waiting for the opportunity to be relocated to a new country.

  13. 47 CFR 80.1117 - Procedure for receipt and acknowledgement of distress alerts.

    Science.gov (United States)

    2010-10-01

    ... false Procedure for receipt and acknowledgement of distress alerts. 80.1117...1117 Procedure for receipt and acknowledgement of distress alerts. (a...calling are only acknowledged using a DSC acknowledgement by a coast station. Ships...

  14. Genetics Home Reference: Spinal muscular atrophy with respiratory distress type 1

    Science.gov (United States)

    ... Recent literature OMIM Genetic disorder catalog Conditions > Spinal muscular atrophy with respiratory distress type 1 (often shortened to ... definitions Reviewed January 2013 What is SMARD1? Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an ...

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

    Science.gov (United States)

    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.

  16. Ground surface temperature simulation for different land covers

    Science.gov (United States)

    Herb, William R.; Janke, Ben; Mohseni, Omid; Stefan, Heinz G.

    2008-07-01

    SummaryA model for predicting temperature time series for dry and wet land surfaces is described, as part of a larger project to assess the impact of urban development on the temperature of surface runoff and coldwater streams. Surface heat transfer processes on impervious and pervious land surfaces were investigated for both dry and wet weather periods. The surface heat transfer equations were combined with a numerical approximation of the 1-D unsteady heat diffusion equation to calculate pavement and soil temperature profiles to a depth of 10 m. Equations to predict the magnitude of the radiative, convective, conductive and evaporative heat fluxes at a dry or wet surface, using standard climate data as input, were developed. A model for the effect of plant canopies on surface heat transfer was included for vegetated land surfaces. Given suitable climate data, the model can simulate the land surface and sub-surface temperatures continuously throughout a six month time period or for a single rainfall event. Land surface temperatures have been successfully simulated for pavements, bare soil, short and tall grass, a forest, and two agricultural crops (corn and soybeans). The simulations were run for three different locations in US, and different years as imposed by the availability of measured soil temperature and climate data. To clarify the effect of land use on surface temperatures, the calibrated coefficients for each land use and the same soil coefficients were used to simulate surface temperatures for a six year climate data set from Albertville, MN. Asphalt and concrete give the highest surface temperatures, as expected, while vegetated surfaces gave the lowest. Bare soil gives surface temperatures that lie between those for pavements and plant-covered surfaces. The soil temperature model predicts hourly surface temperatures of bare soil and pavement with root-mean-square errors (RMSEs) of 1-2 °C, and hourly surface temperatures of vegetation-covered surfaces with RMSEs of 1-3 °C.

  17. Future doctors : Mental distress during medical education: cross-sectional and longitudinal studies

    OpenAIRE

    Dahlin, Marie

    2007-01-01

    Medical education is long and stressful and medical students may suffer from mental distress. The aims of this dissertation are threefold; to investigate levels of distress in medical students at one Swedish medical school, to examine gender differences in such distress and to study individual and environmental determinants of distress. Major outcome measures were self-rated depression, burnout and interviewer-rated psychiatric morbidity. The thesis consists of two cross-sec...

  18. Challenges confronting road freight transport and the use of vehicle-pavement interaction analysis in addressing these challenges

    Scientific Electronic Library Online (English)

    W J vd M, Steyn; C L, Monismith; W A, Nokes; J T, Harvey; T J, Holland; N, Burmas.

    2012-04-01

    Full Text Available Traditional arguments for maintaining riding quality of pavement are expanded in this paper to examine the effects of deteriorating riding quality on vehicle operating costs, freight damage and logistics. The objectives of this paper are to analyse the effects of different levels of riding quality o [...] n a truck and its freight, and to discuss potential applications of the analysis in terms of effectiveness of the freight transport system. The paper discusses needs and drivers influencing freight transport costs, vehicle-pavement interaction concepts, and the potential physical effects and costs from roads with deteriorating riding quality. A case study is presented analysing vehicle-pavement interaction for selected roadways in California. It is concluded that investments in pavement and freight transport industry improvements can be investigated by applying vehicle-pavement interaction analysis to evaluate damage to pavement, vehicle and freight that would result from alternative levels of pavement riding quality. The paper recommends that existing concepts, tools and resources such as dedicated truck lanes and vehicle-pavement interaction analysis can help to improve the freight transport system. A framework is proposed to better understand the scale of potential impacts of riding quality from localised effects to larger-scale influences, including costs to customers and global competitiveness.

  19. Challenges confronting road freight transport and the use of vehicle-pavement interaction analysis in addressing these challenges

    Directory of Open Access Journals (Sweden)

    W J vd M Steyn

    2012-04-01

    Full Text Available Traditional arguments for maintaining riding quality of pavement are expanded in this paper to examine the effects of deteriorating riding quality on vehicle operating costs, freight damage and logistics. The objectives of this paper are to analyse the effects of different levels of riding quality on a truck and its freight, and to discuss potential applications of the analysis in terms of effectiveness of the freight transport system. The paper discusses needs and drivers influencing freight transport costs, vehicle-pavement interaction concepts, and the potential physical effects and costs from roads with deteriorating riding quality. A case study is presented analysing vehicle-pavement interaction for selected roadways in California. It is concluded that investments in pavement and freight transport industry improvements can be investigated by applying vehicle-pavement interaction analysis to evaluate damage to pavement, vehicle and freight that would result from alternative levels of pavement riding quality. The paper recommends that existing concepts, tools and resources such as dedicated truck lanes and vehicle-pavement interaction analysis can help to improve the freight transport system. A framework is proposed to better understand the scale of potential impacts of riding quality from localised effects to larger-scale influences, including costs to customers and global competitiveness.

  20. Evaluating the Infiltration Performance of Eight Dutch Permeable Pavements Using a New Full-Scale Infiltration Testing Method

    Directory of Open Access Journals (Sweden)

    Floris Boogaard

    2014-07-01

    Full Text Available Permeable pavements are a type of sustainable urban drainage system (SUDS technique that are used around the world to infiltrate and treat urban stormwater runoff and to minimize runoff volumes. Urban stormwater runoff contains significant concentrations of suspended sediments that can cause clogging and reduce the infiltration capacity and effectiveness of permeable pavements. It is important for stormwater managers to be able to determine when the level of clogging has reached an unacceptable level, so that they can schedule maintenance or replacement activities as required. Newly-installed permeable pavements in the Netherlands must demonstrate a minimum infiltration capacity of 194 mm/h (540 l/s/ha. Other commonly used permeable pavement guidelines in the Netherlands recommend that maintenance is undertaken on permeable pavements when the infiltration falls below 0.50 m/d (20.8 mm/h. This study used a newly-developed, full-scale infiltration test procedure to evaluate the infiltration performance of eight permeable pavements in five municipalities that had been in service for over seven years in the Netherlands. The determined infiltration capacities vary between 29 and 342 mm/h. Two of the eight pavements show an infiltration capacity higher than 194 mm/h, and all infiltration capacities are higher than 20.8 mm/h. According to the guidelines, this suggests that none of the pavements tested in this study would require immediate maintenance.

  1. A Comparison of High- and Low-Distress Marriages that End in Divorce

    Science.gov (United States)

    Amato, Paul R.; Hohmann-Marriott, Bryndl

    2007-01-01

    We used data from Waves 1 and 2 of the National Survey of Families and Households to study high- and low-distress marriages that end in divorce. A cluster analysis of 509 couples who divorced between waves revealed that about half were in high-distress relationships and the rest in low-distress relationships. These 2 groups were not artifacts of…

  2. Assessment of Distress in Young Children: A Comparison of Autistic Disorder, Developmental Delay, and Typical Development

    Science.gov (United States)

    Esposito, G.; Venuti, P.; Bornstein, M. H.

    2011-01-01

    Distress emotions in very young children are manifest in vocal, facial, and bodily cues. Moreover, children with different developmental conditions (i.e. autistic disorder, AD; developmental delay, DD; typically developing, TD) appear to manifest their distress emotions via different channels. To decompose channel of emotional distress display by…

  3. Brief Report: Associations of Parental Warmth, Peer Support, and Gender with Adolescent Emotional Distress

    Science.gov (United States)

    Operario, Don; Tschann, Jeanne; Flores, Elena; Bridges, Margaret

    2006-01-01

    This is an exploratory study of the associations among parental warmth, peer support, gender, and emotional distress in a sample of 308 adolescents in the United States. Parental warmth was associated with less emotional distress, whereas turning to peers for support during family conflict was associated with more emotional distress. Gender…

  4. Late Financial Distress Process Stages and Financial Ratios : Evidence for Auditors' Goingconcern Evaluation

    DEFF Research Database (Denmark)

    Sormunen, Nina; Laitinen, Teija

    2012-01-01

    The present study adds to our understanding and knowledge of financial distress predictions regarding the usefulness of financial ratios in the late stages of the financial distress process. The study contributes to previous research by generating information concerning: (1) the behavior and usefulness of single financial ratios in short-term financial distress prediction when the effect of each different financial distress process stage is considered; (2) the effects of recognition of the financial distress process stage on the financial distress prediction model. The time horizon for prediction is less than one year, and the empirical data consist of financial statement information from 106 distressed firms undergoing reorganization and their matched counterparts for 2003-2007. To analyze the effects of the specific distress process stage, the sample has been divided into two groups according to the date of application for reorganization: the first group of businesses applied for reorganization between 1 and 182 days after the closing of accounts, and the second group between 183 and 365 days after that point. The study findings provide evidence that the financial distress process stage affects the classification ability of single financial ratios and financial distress prediction models in short-term financial distress prediction. The study shows that the auditor's GC task could be supported by paying attention to the financial distress process stage. The implications of these findings for auditors and every stakeholder of business firms are considered.

  5. Psychological Distress among Nursing, Physiotherapy and Occupational Therapy Students: A Longitudinal and Predictive Study

    Science.gov (United States)

    Nerdrum, Per; Rustoen, Tone; Helge Ronnestad, Michael

    2009-01-01

    In this study, we present longitudinal data on changes in psychological distress among 232 Norwegian undergraduate students of nursing, physiotherapy, and occupational therapy. Psychological distress was assessed by applying the 12-item version of the General Health Questionnaire. Nursing students became substantially more distressed during the…

  6. Life Cycle Assessment of Pavements: A Critical Review of Existing Literature and Research

    Energy Technology Data Exchange (ETDEWEB)

    Santero, Nicholas; Masanet, Eric; Horvath, Arpad

    2010-04-20

    This report provides a critical review of existing literature and modeling tools related to life-cycle assessment (LCA) applied to pavements. The review finds that pavement LCA is an expanding but still limited research topic in the literature, and that the existing body of work exhibits methodological deficiencies and incompatibilities that serve as barriers to the widespread utilization of LCA by pavement engineers and policy makers. This review identifies five key issues in the current body of work: inconsistent functional units, improper system boundaries, imbalanced data for asphalt and cement, use of limited inventory and impact assessment categories, and poor overall utility. This review also identifies common data and modeling gaps in pavement LCAs that should be addressed in future work. These gaps include: the use phase (rolling resistance, albedo, carbonation, lighting, leachate, and tire wear and emissions), asphalt fumes, feedstock energy of bitumen, traffic delay, the maintenance phase, and the end-of-life phase. This review concludes with a comprehensive list of recommendations for future research, which shed light on where improvements in knowledge can be made that will benefit the accuracy and comprehensiveness of pavement LCAs moving forward.

  7. PAHs underfoot: Contaminated dust from coal-tar sealcoated pavement is widespread in the United States

    Science.gov (United States)

    Van Metre, P.C.; Mahler, B.J.; Wilson, J.T.

    2009-01-01

    We reported in 2005 that runoff from parking lots treated with coal-tar-based sealcoat was a major source of polycyclic aromatic hydrocarbons (PAHs) to streams in Austin, Texas. Here we present new data from nine U. S. cities that show nationwide patterns in concentrations of PAHs associated with sealcoat Dust was swept from parking lots in six cities in the central and eastern U. S., where coal-tar-based sealcoat dominates use, and three cities in the western U. S., where asphalt-based sealcoat dominates use. For six central and eastern cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median ?? PAH concentrations in dust from sealcoated and unsealcoated pavement are similar and very low (2. 1 and 0. 8 mg/kg, respectively). Lakes in the central and eastern cities where pavement was sampled have bottom sediments with higher PAH concentrations than do those in the western cities relative to degree of urbanization. Bottom-sediment PAH assemblages are similar to those of sealcoated pavement dust regionally, implicating coal-tar-based sealcoat as a PAH source to the central and eastern lakes. Concentrations of benzo[a]pyrene in dust from coal-tar sealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted.

  8. Reuse of Lathe Waste Steel Scrap in Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Pooja Shrivastavaa

    2014-12-01

    Full Text Available These project works assess on the study of the workability and mechanical strength properties of the concrete reinforced with industrialized waste fibers or the recycled fibers. In each lathe industries wastes are available in form of steel scraps are yield by the lathe machines in process of finishing of different machines parts and dumping of these wastes in the barren soil contaminating the soil and ground water that builds an unhealthy environment. Now a day’s these steel scraps as a waste products used by innovative construction industry and also in transportation and highway industry. In addition to get sustainable progress and environmental remuneration, lathe scrap as worn-recycle fibers with concrete are likely to be used. When the steel scrap reinforced in concrete it acquire a term; fiber reinforced concrete and steel fibers in concrete defined as steel fiber reinforced concrete (SFRC.Different experimental studies are done to identify about fresh and hardened concrete properties of steel scrap fiber reinforced concrete (SSFRC and their mechanical properties are found to be increase due to the addition of steel scrap in concrete i.e. compressive strength, flexural strength, impact strength, fatigue strength and split tensile strength were increased but up to 0.5-2% scrap content . When compared with usual concrete to SSFRC, flexural strength increases by 40% and considerable increases in tensile and compressive strength. These steel scrap also aid to improve the shrinkage reduction, cracking resistance i.e. preventing crack propagation and modulus of elasticity. The workability of fresh SSFRC are carried out by using slump test but it restricted to less scrap contents. This work focuses on the enhancement of structural strength and improvement in fatigue life of concrete pavements by reuse of scrap steel in concrete. These concrete roads with SSFRC promises an appreciably eminent design life, offer superior serviceability and minimize crack growth and corrosion. The pioneer idea of this work is the reuse of waste lathe scrap as recycled steel fibers, which provides more cost-effective and eco-friendly sustainable SFRC PAVEMENTS.

  9. Maternal Distress during Pregnancy and Offspring Childhood Overweight

    DEFF Research Database (Denmark)

    Ingstrup, Katja Glejsted; Schou Andersen, Camilla

    2012-01-01

    Background. Maternal distress during pregnancy increases the intrauterine level of glucocorticoids, which may have long-term health consequences for the child. Objective. To examine if distress as a combined measure of anxiety, depression, and stress of the mother during pregnancy was associated with offspring childhood overweight at age 7. Methods. We performed a cohort study using prospective data from 37,764 women and child dyads from the Danish National Birth Cohort (1996-2002). At a telephone interview at approximately 30 weeks gestation, the women reported whether they felt anxious, depressed, or stressed. The 95 percentile for body mass index in an international reference defined childhood overweight at any given age. Logistic regression was used for the analyses. Results. The prevalence of overweight children at 7 years of age was 9.9%. Prenatal exposure to maternal distress during pregnancy was not associated with childhood overweight at 7 years of age (adjusted OR 1.06 (95%?CI 0.96; 1.18)). In analyses stratified on sex, a small tendency of overweight was seen in boys (OR?1.15 (0.99; 1.33)), but not in girls (OR?0.98 (0.85; 1.13)). Conclusions. Maternal distress during pregnancy appeared to have limited, if any, influence on the risk of overweight in offspring at 7 years of age.

  10. Successful treatment of acute respiratory distress syndrome in 2 dogs

    OpenAIRE

    Kelmer, Efrat; Love, Lydia C.; Declue, Amy E.; Cohn, Leah A.; Bruchim, Yaron; Klainbart, Sigal; Sura, Patti A.; Merbl, Yael

    2012-01-01

    Acute respiratory distress syndrome (ARDS) was diagnosed in 2 dogs with acute dyspnea. Short-term positive pressure ventilation and intense critical and nursing care were provided. Both dogs improved and were discharged. Few reports describe successful recovery from ARDS. Due to advances in positive pressure ventilation and improvement in the supportive care of critically ill veterinary patients, the prognosis for ARDS may improve.

  11. Maladaptive Perfectionism, Hassles, Coping, and Psychological Distress in University Professors

    Science.gov (United States)

    Dunn, Joshua C.; Whelton, William J.; Sharpe, Donald

    2006-01-01

    This study examined the roles of hassles, avoidant and problem-focused coping, and perceived social support as mediating the relationship between maladaptive perfectionism and psychological distress in a sample of university professors. Hassles and avoidant coping both partially mediated a strong association between maladaptive perfectionism and…

  12. The Effect of Reappraising Social Exclusion on Emotional Distress

    Science.gov (United States)

    Kitchens, Michael B.; Gohm, Carol L.

    2010-01-01

    The purpose of this investigation was to examine whether reappraisal, which is a strategy where the personal meaning of an event is reevaluated, would influence participants' emotional reactions to social exclusion feedback. It was expected that reappraising this event would reduce the emotional distress that accompanies social exclusion, but…

  13. Nurse responses to patient expressions of spiritual distress.

    Science.gov (United States)

    Taylor, Elizabeth Johnston; Mamier, Iris

    2013-01-01

    This secondary analysis of data from 200 practicing registered nurses' and student nurses' responses to 3 vignettes depicting patient spiritual distress were evaluated qualitatively and quantitatively (using the Empathic Response Scale). Findings showed wide variation in these nurses' ability to respond empathically; while some responses would be healing, others were potentially hurtful. PMID:23774721

  14. Religiosity and Death Distress in Arabic College Students

    Science.gov (United States)

    Al-Sabwah, Mohammed N.; Abdel-Khalek, Ahmed M.

    2006-01-01

    The purpose of the present study was to explore the relationship between religiosity and death distress (death anxiety, death depression, and death obsession) among a sample (N = 570) of Egyptian women nursing undergraduates, mainly Muslims. Their ages ranged from 17 to 25. The correlations between religiosity and both death anxiety and death…

  15. Pathways among Marital Distress, Parental Symptomatology, and Child Adjustment

    Science.gov (United States)

    Papp, Lauren M.; Mark Cummings, E.; Schermerhorn, Alice C.

    2004-01-01

    A community sample of 295 mothers, fathers, and children M age 11-14 years, SD2.32 years rated marital distress, maternal and paternal psychological symptoms, and child adjustment. The predicted direct relations between these family and child variables were demonstrated for both fathers and mothers. Tests of pathways among these variables were…

  16. Hunger, inhibitory control and distress-induced emotional eating.

    Science.gov (United States)

    van Strien, Tatjana; Ouwens, Machteld A; Engel, Carmen; de Weerth, Carolina

    2014-08-01

    Self-reported emotional eating has been found to significantly moderate distress-induced food intake, with low emotional eaters eating less after a stress task than after a control task and high emotional eaters eating more. The aim of the present study was to explore possible underlying mechanisms by assessing possible associations with (1) ability to experience the typical post-stress reduction of hunger and (2) inhibitory control. We studied these effects in 54 female students who were preselected on the basis of extremely high or low scores on an emotional eating questionnaire. Using a within subject design we measured the difference of actual food or snack intake after a control or a stress task (Trier Social Stress Test). As expected, the moderator effect of emotional eating on distress-induced food intake was found to be only present in females with a failure to report the typical reduction of hunger immediately after a stress task (an a-typical hunger stress response). Contrary to our expectations, this moderator effect of emotional eating was also found to be only present in females with high ability to stop motor impulses (high inhibitory control). These findings suggest that an a-typical hunger stress response but not poor inhibitory control may underlie the moderator effect of emotional eating on distress-induced food intake. However, inhibitory control may play a role whether or not there is a moderator effect of self-reported emotional eating on distress-induced food intake. PMID:24768894

  17. Pregnancy Loss and Distress among U.S. Women

    Science.gov (United States)

    Shreffler, Karina M.; Greil, Arthur L.; McQuillan, Julia

    2011-01-01

    Although pregnancy loss--especially miscarriage--is a relatively common experience among reproductive-aged women, much of our understanding about the experience has come from small clinic-based or other nonrepresentative samples. We compared fertility-specific distress among a national sample of 1,284 women who have ever experienced a stillbirth…

  18. Dual Minority Stress and Asian American Gay Men's Psychological Distress

    Science.gov (United States)

    Chen, Yung-Chi; Tryon, Georgiana Shick

    2012-01-01

    The present study investigated the direct and additive effects of racial minority stress and sexual minority stress on the psychological well-being among a community sample of 139 Asian American gay men. Self-esteem was tested to see whether it moderated or mediated the effects of perceived dual minority stress on psychological distress. Results…

  19. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    Directory of Open Access Journals (Sweden)

    Zheng LU

    2014-12-01

    Full Text Available In this research work, a method to estimate the dynamic characteristics of a multilayered pavement with bituminous or concrete materials is proposed. A mechanical model is established to investigate the dynamic displacement and stress of the multi-layered pavement structure. Both the flexible and the rigid pavements, corresponding to bituminous materials and concrete materials, respectively, are studied. The theoretical solutions of the multi-layered pavement structure are deduced considering the compatibility condition at the interface of the structural layers. By introducing FFT (Fast Fourier Transform algorithm, some numerical results are presented. Comparisons of the theoretical and experimental result implied that the proposed method is reasonable in predicting the stress and displacement of a multi-layered pavement with bituminous or concrete materials. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6071

  20. Prediction of Airport Flexible Pavement Critical Responses from Non-destructive Test Data Using ANN-based Structural Models

    Directory of Open Access Journals (Sweden)

    Kasthurirangan Gopalakrishnan

    2006-01-01

    Full Text Available This study describes the development of Artificial Neural Network (ANN based pavement response prediction models for rapid structural analysis of airport flexible pavements based on Non-destructive Test (NDT data. A finite element based pavement structural model, which can accommodate stress-sensitive geomaterial stiffness models, was used to generate the ANN training and testing dataset. The goal was to establish ANN models for predicting critical responses (stresses and strains from routine NDT airfield pavement structural evaluation data. The developed ANN models predicted the critical pavement responses obtained from the finite element model with good accuracy. Further research is required to achieve increased prediction accuracies and validate the ANN models using actual field data.