WorldWideScience

Sample records for bleeding pavements

  1. Pavement Subgrade Performance Study

    DEFF Research Database (Denmark)

    Zhang, Wei; Ullidtz, Per; Macdonald, Robin

    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...

  2. Permeable pavement study (Edison)

    Data.gov (United States)

    U.S. Environmental Protection Agency — While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types...

  3. Vehicle-Pavement Interaction

    OpenAIRE

    Khavassefat, Parisa

    2014-01-01

    Several aspects of vehicle-pavement interaction have been studied and discussed in this thesis. Initially the pavement response is studied through a quasi-static and a dynamic computationally efficient framework under moving traffic loads. Subsequently, a non-stationary stochastic solution has been developed in order to account for the effect of pavement surface deterioration on pavement service life.The quasi-static procedure is based on a superposition principle and is computationally favou...

  4. [Gastrointestinal bleeding].

    Science.gov (United States)

    Lanas, Ángel

    2015-09-01

    In the Digestive Disease Week in 2015 there have been some new contributions in the field of gastrointestinal bleeding that deserve to be highlighted. Treatment of celecoxib with a proton pump inhibitor is safer than treatment with nonselective NSAID and a proton pump inhibitor in high risk gastrointestinal and cardiovascular patients who mostly also take acetylsalicylic acid. Several studies confirm the need to restart the antiplatelet or anticoagulant therapy at an early stage after a gastrointestinal hemorrhage. The need for urgent endoscopy before 6-12 h after the onset of upper gastrointestinal bleeding episode may be beneficial in patients with hemodynamic instability and high risk for comorbidity. It is confirmed that in Western but not in Japanese populations, gastrointestinal bleeding episodes admitted to hospital during weekend days are associated with a worse prognosis associated with delays in the clinical management of the events. The strategy of a restrictive policy on blood transfusions during an upper GI bleeding event has been challenged. Several studies have shown the benefit of identifying the bleeding vessel in non varicose underlying gastric lesions by Doppler ultrasound which allows direct endoscopic therapy in the patient with upper GI bleeding. Finally, it has been reported that lower gastrointestinal bleeding diverticula band ligation or hemoclipping are both safe and have the same long-term outcomes. PMID:26520197

  5. Pavement Testing Facility

    Data.gov (United States)

    Federal Laboratory Consortium — Comprehensive Environmental and Structural Analyses The ERDC Pavement Testing Facility, located on the ERDC Vicksburg campus, was originally constructed to provide...

  6. Bleeding Disorders

    Science.gov (United States)

    ... times I'd miss work and skip the gym because I felt so lousy. So I decided ... cell called platelets. Your body also needs blood proteins called clotting factors. In people with bleeding disorders, ...

  7. Layered pavement systems

    Science.gov (United States)

    Numerous aspects of the mechanical and structural response of layered pavement systems are discussed. Subgrade moduli for soil that exhibits nonlinear behavior are predicted. The use of a pressure meter test to predict modulus is discussed. Load equivalency factors of triaxial loading for flexible pavements is discussed, as well as a constitutive equation for the permanent strain of sand subjected to cyclic loading.

  8. 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…

  9. Precast concrete pavements

    Science.gov (United States)

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

    1981-11-01

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

  10. A Study on Overlay Design of Repeatedly Deteriorating Flexible Pavement

    Directory of Open Access Journals (Sweden)

    Mahendrakar Kiran Kumar

    2015-06-01

    Full Text Available A factor, which causes further concern in India, is very high and very low pavement temperature in some parts of the country. Under these conditions, flexible pavements tend to become soft in summer and brittle in winter. Further increase in road traffic during the last one decade with an unduly low level of maintenance has contributed to accelerated deterioration of road surfacing. To prevent this deterioration process, several types of measures may be adopted effectively such as improved design, use of high performance materials and effective construction technologies. Over the last two decades, traffic volume and the percentage of heavy truck traffic have increased enormously on the National High Way No 18. This pavement is a Flexible pavement with bituminous surfacing. The high traffic intensity in terms of commercial vehicles, overloading of axles and significant variations in daily and seasonal temperature of the pavement have been always responsible for early development of distress symptoms like undulations, rutting, cracking, bleeding, raveling, shoving and potholing of bituminous surfacing.

  11. Asphalt pavement temperature prediction

    OpenAIRE

    Minhoto, Manuel; Pais, Jorge; Pereira, Paulo

    2006-01-01

    A 3-D finite element model (FEM) was developed to calculate the lemperature of an asphtalt rubber pavement localed in the Northeast of Portugal. The goal of the case study presented in this paper is to show the good accuracy temperature prediction tha can be obtained with this model when compared with the field pavement thermal condition obtained during a year. lnput data to the model are the hourly values for solar radiation and temperature and the mean daily value of wind speed obtained fr...

  12. DRAINAGE AND FLEXIBLE PAVEMENT PERFORMANCE

    Directory of Open Access Journals (Sweden)

    SIDDHARTHA ROKADE

    2012-04-01

    Full Text Available Providing adequate drainage to a pavement system has been considered as an important design consideration to prevent premature failures due to water related problems such as pumping action, loss of support, and rutting, among others. Most water in pavements is due to rainfall infiltration into unsaturated pavement layers, throughjoints, cracks, shoulder edges, and various other defects, especially in older deteriorated pavements. Water also seep upward from a high groundwater table due to capillary suction or vapour movements, or it may flow laterally from the pavement edges and side ditches. Providing adequate drainage to a pavement system has been considered as an important design consideration to ensure satisfactory performance of the pavement, particularly from the perspective of life cycle cost and serviceability. To minimize premature pavement distresses and to enhance the pavement performance, it is imperative to provide adequate drainage to allow infiltrated water to drain out from the base and sub-base, thus avoiding saturation of base and subgrade soils. This paper deals with the analysis of the impact of subsurface drainage on pavement system performance. The requirement ofeffective subsurface drainage for pavement performance is also discussed.

  13. Permeable Pavements at Purdue

    OpenAIRE

    Knapp, Jim

    2013-01-01

    Two case studies will be presented describing sustainable drainage alternatives. The processes used for the 2nd Street project in Seymour will provide a comparison of the design processes for conventional and green infrastructure solutions. Purdue University will discuss a number of permeable pavement installations on campus and provide a map for viewing. Asphalt, concrete, and permeable paver options will be discussed.

  14. 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...

  15. Bleeding Disorders Treatment Options

    Science.gov (United States)

    ... Pictures Young Voices Compendium of Assessment Tools Educational Games Video Library Find a Treatment Centre Haemophilia Journal About Bleeding Disorders Bleeding Disorders The Clotting Process Drugs That Can Cause Bleeding Hemophilia How Do You ...

  16. 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...

  17. Geotextiles in Flexible Pavement Construction

    Science.gov (United States)

    Alungbe, Gabriel D.

    2004-01-01

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

  18. Pavement roughness and skid properties

    Science.gov (United States)

    Road roughness and roadway safety as it relates to both surface and air transportation are discussed. The role of road roughness in vehicle ride, the measurement of roughness, the evaluation of riding confort, and the effect of grooving pavements are discussed. The effects of differential pavement friction on the response of cars in skidding maneuvers is discussed.

  19. Procedures and Technologies for Pavement Monitoring

    OpenAIRE

    GEORGE, Luc Amaury; Brosseaud, Yves

    2009-01-01

    Pavement Monitoring (surface and structure). Surface characteristics - main indicators Pavement structures (non destructive testings). Monitoring objectives. Devices and indicators used in France Innovation & Research. Measurement's use by roads owners. Main road network (States & motorway concessionaires). Local and urban road networks. Some maintenance techniques. High modulus mixtures and very thin mixtures. Pavement in situ recycling Pavement in plan recycling. Low noise & coloured ...

  20. USE OF RECLAIMED ASPHALT PAVEMENT WITH MILLED ROAD PAVEMENT LAYERS

    OpenAIRE

    Andrzej Plewa; Marta Wasilewska; Władysław Gardziejczyk; Paweł Gierasimiuk

    2015-01-01

    The article presents the results of research on the functional properties of asphalt mixes using RAP obtained from milling asphalt road pavements. Asphalt concrete AC 22P with 0%, 10%, 15% and 20% addition of RAP used for base course of road pavements were designed. It was found that asphalt mixes with RAP characterized by comparable and in some cases better functional properties compared to the asphalt mixes without RAP (0%). One should notice the influence of RAP on the performance and ...

  1. Permanent deformation of flexible pavements

    Science.gov (United States)

    Brown, S. F.; Broderick, B. V.; Pappin, J. W.

    1980-06-01

    Seven pairs of pavements with granular bases were tested under controlled conditions. One pavement in each pair contained fabric inclusions. An improved testing facility was developed, including: (1) servo-hydraulic system for the loading carriage; (2) amplification and read-out system for pressure cells; (3) linearizing unit for strain coils; (4) transducers for measuring vertical and resilient deflection; (5) techniques for measuring in situ strain on fabric inclusions; (6) extensive use of nuclear density meter to monitor pavement and foundation materials. The following conclusions are drawn: (1) No improvement in performance resulted from fabric inclusions. (2) No consistent reduction in in-situ stresses, resilient strains, or permanent strains was observed as a result of fabric inclusion. (3) No consistent improvement in densities resulted from fabric inclusions. (4) Some slip apparently occurred between fabric and soil on those pavements which involved large deformations. The slip occurred between fabric and crushed limestone base rather than between fabric and silty-clay subgrade.

  2. Pervious Pavement System Evaluation- Abstract

    Science.gov (United States)

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

  3. [Acute gastrointestinal bleeding].

    Science.gov (United States)

    Baumbach, Robert; Faiss, Siegbert; Cordruwisch, Wolfgang; Schrader, Carsten

    2016-04-01

    Acute gastrointestinal bleeding is a common major emergency (Internal medical or gastroenterological or medical), approximately 85 % of which occur in the upper GI tract. It is estimated that about a half of upper GI bleeds are caused by peptic ulcers. Upper GI bleeds are associated with more severe bleeding and poorer outcomes when compared to middle or lower GI bleeds. Prognostic determinants include bleeding intensity, patient age, comorbid conditions and the concomitant use of anticoagulants. A focused medical history can offer insight into the bleeding intensity, location and potential cause (along with early risk stratification). Initial measures should focus on rapid assessment and resuscitation of unstable patients. The oesophagogastroduodenoscopy (OGD) is the gold standard method for localizing the source of bleeding and for interventional therapy. Bleeding as a result of peptic ulcers is treated endoscopically with mechanical and / or thermal techniques in combination with proton pump inhibitor (PPI) therapy. When variceal bleeding is suspected, pre-interventional use of vasopressin analogues and antibiotic therapies are recommended. Endoscopically, the first line treatment of esophageal varices is endoscopic ligature therapy, whereas that for gastric varices is the use of Histoacryl injection sclerotherapy. When persistent and continued massive hemorrhage occurs in a patient with known or suspected aortic disease the possibility of an aorto-enteric fistula must be considered. PMID:27078246

  4. Quantifying Evaporation in a Permeable Pavement System

    Science.gov (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  5. Dynamic contracting mechanism for pavement maintenance management

    NARCIS (Netherlands)

    Demirel, H.C.; De Ridder, H.A.J.

    2013-01-01

    Technological advances, financial possibilities and changes of demands have increasingly affected the pavement maintenance environment for outsourcing in recent years. This induces complexity in the contracting methods of pavement maintenance activities. Despite the fact that current contracting pra

  6. 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...

  7. Recycling of asphalt pavements with asphalt rubber

    OpenAIRE

    Pais, Jorge; Pereira, Paulo; Minhoto, Manuel; Baptista, António

    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...

  8. USE OF RECLAIMED ASPHALT PAVEMENT WITH MILLED ROAD PAVEMENT LAYERS

    Directory of Open Access Journals (Sweden)

    Andrzej Plewa

    2015-07-01

    Full Text Available The article presents the results of research on the functional properties of asphalt mixes using RAP obtained from milling asphalt road pavements. Asphalt concrete AC 22P with 0%, 10%, 15% and 20% addition of RAP used for base course of road pavements were designed. It was found that asphalt mixes with RAP characterized by comparable and in some cases better functional properties compared to the asphalt mixes without RAP (0%. One should notice the influence of RAP on the performance and durability of the asphalt mixtures, as compared to virgin asphalt mixtures (without RAP.

  9. Teaching Methodology of Flexible Pavement Materials and Pavement Systems

    Science.gov (United States)

    Mehta, Yusuf; Najafi, Fazil

    2004-01-01

    Flexible pavement materials exhibit complex mechanical behavior, in the sense, that they not only show stress and temperature dependency but also are sensitive to moisture conditions. This complex behavior presents a great challenge to the faculty in bringing across the level of complexity and providing the concepts needed to understand them. The…

  10. Tuning in to pavement radio

    NARCIS (Netherlands)

    Ellis, S.D.K.

    1989-01-01

    This article describes a phenomenon known all over Africa, for which there is no really satisfactory term in English but which is summed up in the French term 'radio trottoir', literally 'pavement radio'. It may be defined as the popular and unofficial discussion of current affairs in Africa, partic

  11. 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…

  12. Simplified Pavement Design for LPAs: Introduction to PaveXpress

    OpenAIRE

    Bonte, Dudley

    2015-01-01

    Simplified Pavement Design for LPA's; An introduction to and use of PaveXpress, a simplified, free, web-based pavement design scoping tool for roadway and parking lot pavements. The system was developed by Pavia Systems in partnership with the National Asphalt Pavement Association. PaveXpress creates technical sound pavement structural designs for flexible and rigid pavements based on widely accepted industry standards from the Association of State Highway Officials (AASHTO). The simplified p...

  13. Pavement Preservation for Elected Officials: The Inside Story of Pavement Deterioration

    OpenAIRE

    Olson, Jim

    2012-01-01

    This session is intended to provide elected officials and practitioners with an introduction to the concept of pavement preservation and its applicability within public agencies. Topics include definitions, budget planning, pavement life, road networks, alternative strategies, pavement distresses, guidelines and preservation treatments.

  14. Impact of Overweight Traffic on Pavement Life Using Weigh-In-Motion Data and Mechanistic-Empirical Pavement Analysis

    OpenAIRE

    Wang, Hao; Zhao, Jingnan; Wang, Zilong

    2015-01-01

    The objective of this study is to evaluate the impact of overweight traffic on pavement life using mechanistic-empirical analysis approach. The state-of-practice mechanistic-empirical pavement design and analysis software (Pavement-ME) was used to predict pavement life under different traffic loading scenarios. Field performance data at the sites where the WIM data were collected were analyzed to estimate the pavement service life at field condition. The pavement structures considered in the ...

  15. Mechanical Response Analysis of Asphalt Pavement Structure

    Directory of Open Access Journals (Sweden)

    Yu Zhenqing

    2015-11-01

    Full Text Available Generally, the Chinese designed life of the high- grade asphalt concrete pavement is required 15 years, however, the designed life of the road in surface is often lower than the designed life, and even premature failure. Especially in heavy traffic conditions, the early damage of some high grade-asphalt pavement in China is serious. According to some investigations, we founded the main reason of the long-life asphalt pavement is to determine the function of each structure layer. According to the stress of pavement structure layer, so as to select the structure layer materials. Based on the viewpoint of mechanics, asphalt pavement damage mode is divided into three categories, such as top-down crack, fatigue cracking and rutting. Therefore, this paper uses ANSYS finite element software as calculation tool, the combination of road vehicle load and the primary influence on asphalt pavement structure mechanics response characteristics were analyzed. In this paper, the method of analysis is control variable: that means under different vehicle axle load, only change surface layer modulus and observe the pavement structure mechanical response trends to compare the effect. By using the same method, the response of the pavement base course parameters to the pavement mechanical structure is analyzed.

  16. Long Life Pavements; Firmes de larga duracion

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

    The existence of long-life pavements is not new; they have been built in Europe and the United States for decades. In fact, the concept arises from the observation of in-service roads; it was verified how particular pavements, initially designed for a 20-year service life, did not seem to have reduced the bearing capacity along the time, and its maintenance necessities had been exclusively focused on the wearing course. The base idea of long-life pavements is the existence of a fatigue threshold below which the damage produced by each load application is, in practice, zero or below the healing potential of the asphalt mix. The use practice of long-life pavements design considers a pavements constituted by three asphalt layers, each one with a very specific role: a wearing course that provides with the surface characteristics, an intermediate course that provides with most of the structural capacity and a base course that provides with the fatigue resistance. Furthermore, one of the particularities is the design against specific distress mechanisms. Maintenance strategy also presents specific particularities for long-life pavements. It is essentially focused on the detection of surface deterioration, and the appropriate and timely repair, before the damage extends beyond the wearing course, putting into risk the structural integrity of the pavement. Nowadays, this new way to conceive the design, the construction and the maintenance of road pavements, constitutes one of the main challenges for pavement engineering worldwide. (Author) 5 refs.

  17. Flexible pavement performance evaluation using deflection criteria

    Science.gov (United States)

    Wedner, R. J.

    1980-04-01

    Flexible pavement projects in Nebraska were monitored for dynamic deflections, roughness, and distress for six consecutive years. Present surface conditions were characterized and data for evaluating rehabilitation needs, including amount of overlay, were provided. Data were evaluated and factors were isolated for determining the structural adequacy of flexible pavements, evaluating existing pavement strength and soil subgrade conditions, and determining overlay thickness requirements. Terms for evaluating structural condition for pavement sufficiently ratings were developed and existing soil support value and subgrade strength province maps were evaluated.

  18. Structural Evaluation for Maputo Airport Pavement

    Institute of Scientific and Technical Information of China (English)

    Jose F.R.Diogo; LU Yang; ZHANG Hua

    2007-01-01

    Maputo Airport was initially constructed to serve mixed traffic of light and medium aircrafts. With its opening to heavier aircrafts such as B727, DC10, Airbus 340, etc. , structural improvements have become necessary. For this purpose, structural evaluation were described and performed using falling weight deflectometer. Results show that while subgrade response to loads appears more consistent with depth, surface layer of the pavement is significantly influenced by the layer thickness as well as mechanical properties of pavement materials. Load magnitude also affects pavement performance. But loading conditions show an equivalent or even greater influence on pavement performance.

  19. Bleeding during Pregnancy

    Science.gov (United States)

    ... have placenta accreta, you are at risk of life-threatening blood loss during delivery. Your ob-gyn will plan your ... to be done right after delivery to prevent life-threatening blood loss. Can bleeding be a sign of preterm labor? ...

  20. Modelling Flexible Pavement Response and Performance

    DEFF Research Database (Denmark)

    Ullidtz, Per

    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.......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....

  1. Numerical Simulation of Tire-Pavement Interaction

    NARCIS (Netherlands)

    Srirangam, S.K.

    2015-01-01

    Good skid resistance of a pavement surface is essential for road safety. Loss of skid resistance can lead to property damage and loss of lives. Ever increasing need of driver safety poses challenges to the highway authorities to evaluate pavement conditions even more precisely under different condit

  2. Analysis and design optimization of flexible pavement

    Energy Technology Data Exchange (ETDEWEB)

    Mamlouk, M.S.; Zaniewski, J.P.; He, W.

    2000-04-01

    A project-level optimization approach was developed to minimize total pavement cost within an analysis period. Using this approach, the designer is able to select the optimum initial pavement thickness, overlay thickness, and overlay timing. The model in this approach is capable of predicting both pavement performance and condition in terms of roughness, fatigue cracking, and rutting. The developed model combines the American Association of State Highway and Transportation Officials (AASHTO) design procedure and the mechanistic multilayer elastic solution. The Optimization for Pavement Analysis (OPA) computer program was developed using the prescribed approach. The OPA program incorporates the AASHTO equations, the multilayer elastic system ELSYM5 model, and the nonlinear dynamic programming optimization technique. The program is PC-based and can run in either a Windows 3.1 or a Windows 95 environment. Using the OPA program, a typical pavement section was analyzed under different traffic volumes and material properties. The optimum design strategy that produces the minimum total pavement cost in each case was determined. The initial construction cost, overlay cost, highway user cost, and total pavement cost were also calculated. The methodology developed during this research should lead to more cost-effective pavements for agencies adopting the recommended analysis methods.

  3. 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...

  4. 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.

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

    Directory of Open Access Journals (Sweden)

    Sina Mirzapour Mounes

    2014-01-01

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

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

    Science.gov (United States)

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

    2014-01-01

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

  7. Theoretical Development and Engineering Practice of Pavements in China

    Institute of Scientific and Technical Information of China (English)

    QIU Yan-jun

    2008-01-01

    This paper presents a comprehensive review of historical theory development and current construction practice of pavement engineering in China. Mechanical models, design guides, construction techniques, evaluation methods and maintenance standards are elaborated for Portland cement concrete (PCC) pavements and asphalt concrete (AC) pavements. Differences in design methodology among pavements of rural highways, urban roads and airport fields are discussed based on service requirements.Lessons and experiences based on the past 20 years' construction practice and pavement performance are summarized. Current research areas in pavement engineering associated with unconventional geological and/or landscaping in China's highway construction and national strategic plan for pavement engineering are also covered.

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

    Science.gov (United States)

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

    2014-01-01

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

  9. Aircraf landing gear design in respect of pavement design

    OpenAIRE

    Fabre, C.; ALBIN, A; Balay, Jean Maurice

    2009-01-01

    This paper considers the close relationship between aircraft landing gear (LG) and pavement design in respect of airfield pavement compatibility. In pavement design and analysis, we usually deal with pavement structures, materials and design thickness procedure but rarely aircraft LG design This paper emphasizes key drivers, which must be considered for new aircraft LG design to achieve aircraft pavement compatibility. Several parameters such as number & size of wheels, type of gear, brakes, ...

  10. 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

  11. Mechanistic design concepts for conventional flexible pavements

    Science.gov (United States)

    Elliott, R. P.; Thompson, M. R.

    1985-02-01

    Mechanical design concepts for convetional flexible pavement (asphalt concrete (AC) surface plus granular base/subbase) for highways are proposed and validated. The procedure is based on ILLI-PAVE, a stress dependent finite element computer program, coupled with appropriate transfer functions. Two design criteria are considered: AC flexural fatigue cracking and subgrade rutting. Algorithms were developed relating pavement response parameters (stresses, strains, deflections) to AC thickness, AC moduli, granular layer thickness, and subgrade moduli. Extensive analyses of the AASHO Road Test flexible pavement data are presented supporting the validity of the proposed concepts.

  12. 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.

  13. Story: A Bleeding Watermelon

    Directory of Open Access Journals (Sweden)

    Nor bzang

    2010-12-01

    Full Text Available A Bleeding Watermelon was written by Norsang (Nor bzang;b. 1988, a native of Dpa ris (Rab rgyas (Huazangsi 华藏寺 Township, Tianzhu 天祝 Tibetan Autonomous County,Gansu 甘肃 Province. Norsang writes: I heard that a university student opened an elevator door in a campus building still under construction. The elevator shaft was empty and he fell to his death. Many people had questions about his death. This inspired me to write this story.

  14. 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. ...

  15. Pervious Pavement System Evaluation- Abstract 1

    Science.gov (United States)

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

  16. Children, urban care, and everyday pavements

    OpenAIRE

    Kim Kullman

    2014-01-01

    This paper takes a mundane piece of urban infrastructure, the pavement, as a starting point, approaching it through the experiences of 7–12-year-old children who journey between home and school in Helsinki, Finland. In doing so, the paper argues that the children and their travel companions are employing pavements to cultivate the caring potential of their city, whether this entails patting dogs, picking up empty bottles, or checking the safety of zebra crossings. Inspired by recent work on t...

  17. Environmental interactions of Sulphlex pavement.

    Science.gov (United States)

    Ferenbaugh, R W; Gladney, E S; Soholt, L F; Lyall, K A; Kimber Wallwork-Barber, M; Herman, L E

    1992-01-01

    Sulphlex, a mixture of elemental sulfur and plasticizers, has been considered for use as an asphalt substitute in road construction. Because this material contains substantial quantities of elemental sulfur, it is a potential substrate for growth of sulfur-oxidising bacteria. Experiments, performed to determine the susceptibility of Sulphlex in Sulphlex-containing media to degradation by Thiobacillus thiooxidans, resulted in breakdown of the Sulphlex material and concomitant production of acid. In concurrent studies, plants were grown in Sulphlex-amended soils. These plants exhibited higher sulfur content and reduced productivity as compared with plants grown in unamended soils, indicating that Sulphlex was being broken down in the soil and that the breakdown products were apparently having a detrimental effect on plant productivity. These experiments indicate that naturally occurring sulfur-oxidising bacteria have the potential to break down Sulphlex paving material, resulting in adverse effects on both the structural integrity of the pavement and the local environment. PMID:15091995

  18. Abnormal uterine bleeding.

    Science.gov (United States)

    Whitaker, Lucy; Critchley, Hilary O D

    2016-07-01

    Abnormal uterine bleeding (AUB) is a common and debilitating condition with high direct and indirect costs. AUB frequently co-exists with fibroids, but the relationship between the two remains incompletely understood and in many women the identification of fibroids may be incidental to a menstrual bleeding complaint. A structured approach for establishing the cause using the Fédération International de Gynécologie et d'Obstétrique (FIGO) PALM-COEIN (Polyp, Adenomyosis, Leiomyoma, Malignancy (and hyperplasia), Coagulopathy, Ovulatory disorders, Endometrial, Iatrogenic and Not otherwise classified) classification system will facilitate accurate diagnosis and inform treatment options. Office hysteroscopy and increasing sophisticated imaging will assist provision of robust evidence for the underlying cause. Increased availability of medical options has expanded the choice for women and many will no longer need to recourse to potentially complicated surgery. Treatment must remain individualised and encompass the impact of pressure symptoms, desire for retention of fertility and contraceptive needs, as well as address the management of AUB in order to achieve improved quality of life. PMID:26803558

  19. Pavement Performance Index for Indian rural roads

    Directory of Open Access Journals (Sweden)

    Abhay Tawalare

    2016-09-01

    Full Text Available The performance of a road is evaluated from time to time so as to improve its quality and helps in planning maintenance of roads. For this purpose various pavement deteriorating models as a decision tool are available. But they are not easy to use for field engineers due to either huge past data requirement or complicated calculations. Therefore, this paper presents a Pavement Performance Index for rural roads by using simple methodology. The distress parameters of rural roads were identified through literature review. Similarly rating criteria for each distress parameters were identified through literature. For final selection of distress parameters in context of Indian rural road, opinions of five highly experienced industrial experts were taken. After that the weightage for severity of each parameter causing distress of pavement is calculated by using data of questionnaire survey in which 117 professionals working in Pradhan Mantri Gram Sadak Yojana across the country were participated. The paper suggests a formula to decide Pavement Performance Index that depends on rating criterion and severity weightage of distress parameters of pavement performance. The study concluded that suggested Pavement Performance Index makes calculations easy for field engineers and will be useful to decide priority list of rural roads for repair and maintenance schedule.

  20. 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

  1. FLEXIBLE PAVEMENT REHABILITATION DESIGN BASED ON PAVEMENT SERVICE LIFE TIME SPAN LEFT

    OpenAIRE

    Gamelyak, I.; Shevchuk, V.

    2005-01-01

    The design of flexible pavement rehabilitation is analysed in terms of durability-cost. A notion of the remaining service life span is described. the model of rehabilitation strategy selection is presented for both design project and operation stages. the results can be used in the pavement management system.

  2. 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.

  3. Coronary interventions in patients with bleeding and bleeding tendency

    Institute of Scientific and Technical Information of China (English)

    Thach Nguyen; Lan Nguyen

    2007-01-01

    @@ In general, percutaneous coronary intervention (PCI)is contra-indicated in patients with bleeding and those that are easy to bleed because during PCI the patients need full anticoagulation to counter any thrombotic formation caused by introduction and manipulation of devices in the vascular system.

  4. Gastrointestinal bleeding under dabigatran

    Directory of Open Access Journals (Sweden)

    C Stöllberger

    2014-01-01

    Full Text Available Dabigatran-absorption is dependent on the intestinal P-glycoprotein (P-gp-system, and P-gp activity is modulated by several drugs. We report an 83-old female with atrial fibrillation who developed gastrointestinal bleeding. She was under a therapy with non-steroidal anti-inflammatory drugs (NSAID and P-gp-modulating drugs and renal function was impaired. We conclude that NSAID and P-gp-modulating drugs should be avoided in dabigatran-treated patients. If renal function deteriorates the dabigatran-dosage should be reduced or the therapy should be stopped. There is an urgent need to increase knowledge about drug interactions with dabigatran.

  5. Locating the Drainage Layer for Bituminous Pavements in Indiana

    OpenAIRE

    Hassan, Hossam Farouk.; White, Thomas D.

    1996-01-01

    Pavement subsurface drainage and its effect on pavement performance has been a subject of interest since the 18th and 19th centuries. With no doubt the detrimental effects of heavy wheel loads on pavements with saturated base material is a significant factor. The consequence of subsurface water on pavement performance includes premature rutting, cracking, faulting, and increased roughness, all of which lead to a decrease in serviceability. This research study involves the evaluation of the...

  6. Porous Flame-retarded Asphalt Pavement for Highway Tunnel

    Institute of Scientific and Technical Information of China (English)

    HU Shuguang; HUANG Shaolong; Ding Qingjun

    2008-01-01

    A new way to improve the tunnel fire protection by using flame-retarded porous asphalt pavement containing ATH powders was introduced. Based on the miniature burning test designed and conducted, the burning time and temperature of porous asphalt (PA) and flame-retarded porous asphalt (FRPA) were studied comparing with cement concrete pavement, dense-graded HMA and S MA. Results of burning test and pavement performance test indicate that FRPA is appropriate and suitable as the pavement material of highway tunnel.

  7. Knowledge Discovery and Pavement Performance: Intelligent Data Mining

    NARCIS (Netherlands)

    Miradi, M.

    2009-01-01

    The main goal of the study was to discover knowledge from data about asphalt road pavement problems to achieve a better understanding of the behavior of them and via this understanding improve pavement quality and enhance its lifespan. Four pavement problems were chosen to be investigated; raveling

  8. Performance of pavements designed with low-cost materials

    Science.gov (United States)

    Grau, R. W.; Yrjanson, W. A.; Packard, R. G.; Barksdale, R. D.; Potts, C. F.; Ruth, B. E.; Smith, L. L.; Huddleston, I. J.; Vinson, T. S.; Hicks, R. G.

    1980-04-01

    The following areas are discussed. Utilization of marginal aggregate materials for secondary road surface layers; econocrete pavements; current practices; construction and performance of sand-asphalt bases and performance of sand-asphalt and limerock pavements in Florida. Cement stabilization of degrading aggregates use of crushed stone screenings in highway construction (abridgement); and sulfur-asphalt pavement technology are also reviewed.

  9. Effect of age of permeable pavements on their infiltration function

    NARCIS (Netherlands)

    Boogaard, Floris; Lucke, Terry; Beecham, Simon

    2013-01-01

    This study describes field investigations designed to compare the infiltration capacities of 55 permeable pavement systems installed in the Netherlands and in Australia. The ages of the pavements varied from 1 to 12 years. Using infiltrometer testing, the performance of the pavements has been compar

  10. 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.

  11. Vitamin K deficiency bleeding of the newborn

    Science.gov (United States)

    Vitamin K deficiency bleeding of the newborn (VKDB) is a bleeding disorder in babies. It most often ... A lack of vitamin K may cause severe bleeding in newborn babies. Vitamin K plays an important role in blood clotting. Babies often ...

  12. Design of airport pavements for expansive soils

    Science.gov (United States)

    McKeen, R. G.

    1981-01-01

    Expansive soil subgrades exhibit volume changes with variation in moisture condition. These changes result in differential movement of airport pavements resting on these soils. Special design procedures must be used to account for the expansive soil activity during equilibration. In addition, special precautions are required to protect the subgrade from moisture variation with climate. Measurement of soil suction is a key step in quantifying moisture-induced soil behavior. Procedures are outlined for suction characterization of the soil and for estimating the in situ differential movement likely to occur under the pavement. Once the wavelength and amplitude characteristics of the differential movement are obtained, design calculations to select the thickness and materials for the pavement may proceed.

  13. Construction of an experimental sulfur-extended-asphalt pavement

    Science.gov (United States)

    Dodge, K. S.

    1982-07-01

    The design, placement and collection of initial data from a sulfur extended asphalt (SEA) pavement and a conventional pavement used as a control is documented. The SEA pavement used 30 percent sulfur by total weight of the binder. Mix temperatures, hot bin gradations, and toxic emissions were monitored at the plant and the site throughout placement. Aggregates were collected from the hot bin during production of the control and SEA mixes for use in a Marshall mix design. Cores were extracted from both SEA and control pavements 1 month after placement for laboratory testing. Pavement surface properties were also examined after 1 month of service.

  14. Acute variceal bleeding: general management

    Institute of Scientific and Technical Information of China (English)

    David Patch; Lucy Dagher

    2001-01-01

    @@ TREATMENT STRATEGIES FOR ACUTE VARICEAL BLEEDING Backgound Acute variceal bleeding has a significant mortality which ranges form 5% to 50% in patients with cirrhosis[1].Overall survival is probably improving,because of new therapeutic approaches,and improved medical care.However,mortality is still closely related to failure to control hacmorrhage or carly rebleeding,which is a distinct characteristic of portal hypertensive bleeding and occures in as many as 50% of patients in the first days to 6 weeks after admission et al[2].

  15. Structural Design of Pavement Overlays Based on Functional Parameters

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    This paper reports a practical pavement overlay design methodbased on PCI (Pavement Condition Index). Current pavement investigation method (JTJ 073-96) is compared to the ASTM D 5340, which is the standard test method for airport pavement condition evaluation initially developed for US Air Force. The deficiency in the calculation of PCI based on field data in JTJ 073 is discussed. The proposed design method is compared to AASHTO overlay design method with good agreement. The paper concludes with an example illustrating how the existing pavement structural capacity is related to pavement distress survey results. The presented design method can be used in the design for overlay rehabilitation of pavements of highways, urban streets and airports.

  16. Bleeding in the Digestive Tract

    Science.gov (United States)

    ... lining of the esophagus, stomach, or duodenum. The bacteria Helicobacter pylori (H. pylori) and use of nonsteroidal ... paleness shortness of breath vomit that looks like coffee grounds weakness A person with acute bleeding may ...

  17. Management of bleeding gastroduodenal ulcers

    DEFF Research Database (Denmark)

    Laursen, Stig Borbjerg; Jørgensen, Henrik Stig; Schaffalitzky de Muckadell, Ove B

    2012-01-01

    Description: A multidisciplinary group of Danish experts developed this guideline on management of bleeding gastroduodenal ulcers. Sources of data included published studies up to March 2011. Quality of evidence and strength of recommendations have been graded. The guideline was approved...

  18. Fibrinogen concentrate in bleeding patients

    DEFF Research Database (Denmark)

    Wikkelsø, Anne; Lunde, Jens; Johansen, Mathias;

    2013-01-01

    Hypofibrinogenaemia is associated with increased morbidity and mortality, but the optimal treatment level, the use of preemptive treatment and the preferred source of fibrinogen remain disputed. Fibrinogen concentrate is increasingly used and recommended for bleeding with acquired haemostatic...

  19. Asphalt for draining pavement; Haisuisei hosoyo asphalt

    Energy Technology Data Exchange (ETDEWEB)

    Yamamori, H.; Nakamura, Y. [Mitsubishi Oil Co. Ltd., Tokyo (Japan)

    1994-12-28

    The effect and functions of draining pavement with a superb performance as a paved road were introduced. In the draining pavement, a porous asphalt mixture was used for the surface and base layers of the road and the remaining layers are not in water penetration property. It is necessary that void continues to prevent water film from being generated when rain falls and resistance against water flow is small but durability has problems when the void rate is large. According to the balance, the void rate ranges from 20 to 23 % for execution, thus preventing water splash on a rainy day, hydroplaning, and dazzlement, etc. due to reflection of light. The noise during driving due to the tire of an automobile is reduced by 5 to 6 dB owing to draining pavement. Also, engine noise is reduced to 40 - 60 % since the surface is porous. In the draining pavement, a high-viscosity asphalt is used for a binder and the void rate is large, thus preventing temperature to rise easily due to heat release and achieving an improved flow behavior. 6 refs., 11 figs., 14 tabs.

  20. 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...

  1. Development of New Bituminous Pavement Design Method

    DEFF Research Database (Denmark)

    Ullidtz, Per

    The report and work of COST Action 333 sets in place the foundation for a coherent, cost-effective and harmonised European pavement design method. In order to do this, the work programme focused on information gathering, identification of requirements and the selection of the necessary design...

  2. Viscoelastic Pavement Modeling with a Spreadsheet

    DEFF Research Database (Denmark)

    Levenberg, Eyal

    2016-01-01

    The aim herein was to equip civil engineers and students with an advanced pavement modeling tool that is both easy to use and highly adaptive. To achieve this, a mathematical solution for a layered viscoelastic half-space subjected to a moving load was developed and subsequently implemented...

  3. [Direct oral anticoagulant associated bleeding].

    Science.gov (United States)

    Godier, A; Martin, A-C; Rosencher, N; Susen, S

    2016-07-01

    Direct oral anticoagulants (DOAC) are recommended for stroke prevention in atrial fibrillation and for the treatment of venous thromboembolism. However, they are associated with hemorrhagic complications. Management of DOAC-induced bleeding remains challenging. Activated or non-activated prothrombin concentrates are proposed, although their efficacy to reverse DOAC is uncertain. Therapeutic options also include antidotes: idarucizumab, antidote for dabigatran, has been approved for use whereas andexanet alpha, antidote for anti-Xa agents, and aripazine, antidote for all DOAC, are under development. Other options include hemodialysis for the treatment of dabigatran-associated bleeding and administration of oral charcoal if recent DOAC ingestion. DOAC plasma concentration measurement is necessary to guide DOAC reversal. We propose an update on DOAC-associated bleeding, integrating the availability of dabigatran antidote and the critical place of DOAC concentration measurements. PMID:27297642

  4. Endoscopic management of diverticular bleeding.

    Science.gov (United States)

    Rustagi, Tarun; McCarty, Thomas R

    2014-01-01

    Diverticular hemorrhage is the most common reason for lower gastrointestinal bleeding (LGIB) with substantial cost of hospitalization and a median length of hospital stay of 3 days. Bleeding usually is self-limited in 70-80% of cases but early rebleeding is not an uncommon problem that can be reduced with proper endoscopic therapies. Colonoscopy is recommended as first-line diagnostic and therapeutic approach. In the vast majority of patients diverticular hemorrhage can be readily managed by interventional endotherapy including injection, heat cautery, clip placement, and ligation to achieve endoscopic hemostasis. This review will serve to highlight the various interventions available to endoscopists with specific emphasis on superior modalities in the endoscopic management of diverticular bleeding.

  5. Endoscopic Management of Diverticular Bleeding

    Directory of Open Access Journals (Sweden)

    Tarun Rustagi

    2014-01-01

    Full Text Available Diverticular hemorrhage is the most common reason for lower gastrointestinal bleeding (LGIB with substantial cost of hospitalization and a median length of hospital stay of 3 days. Bleeding usually is self-limited in 70–80% of cases but early rebleeding is not an uncommon problem that can be reduced with proper endoscopic therapies. Colonoscopy is recommended as first-line diagnostic and therapeutic approach. In the vast majority of patients diverticular hemorrhage can be readily managed by interventional endotherapy including injection, heat cautery, clip placement, and ligation to achieve endoscopic hemostasis. This review will serve to highlight the various interventions available to endoscopists with specific emphasis on superior modalities in the endoscopic management of diverticular bleeding.

  6. Management of bleeding gastroduodenal ulcers

    DEFF Research Database (Denmark)

    Laursen, Stig Borbjerg; Jørgensen, Henrik Stig; Schaffalitzky de Muckadell, Ove B.

    2012-01-01

    serious ulcer bleeding is suspected and blood found in gastric aspirate, endoscopy within 12 hours will result in faster discharge and reduced need for transfusions. Endoscopic hemostasis remains indicated for high-risk lesions. Clips, thermocoagulation, and epinephrine injection are effective......Description: A multidisciplinary group of Danish experts developed this guideline on management of bleeding gastroduodenal ulcers. Sources of data included published studies up to March 2011. Quality of evidence and strength of recommendations have been graded. The guideline was approved......-risk stigmata. Although selected patients can be discharged promptly after endoscopy, high-risk patients should be hospitalized for at least 3 days after endoscopic hemostasis. Patients with peptic ulcer bleeding who require secondary cardiovascular prophylaxis should start receiving acetylsalicylic acid (ASA...

  7. MODELING PAVEMENT DETERIORATION PROCESSES BY POISSON HIDDEN MARKOV MODELS

    Science.gov (United States)

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

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

  8. An Airport Pavement Traffic Simulation Based on CPN

    OpenAIRE

    Heng Hong-jun; Yang Jue

    2014-01-01

    According to the characteristics of airport pavement traffic, we discuss a method of building an airport pavement traffic model which is based on CPN theory and simulate a practical situation as well. The method overcomes the shortage of modelling with normal Petri Net theory, solves the difficult problems of airport pavement traffic such as complex traffic nets, frequent road changing, etc., refines the process of the model, and will be good for the model’s analysis and simulation.

  9. Recent Developments in Pavement Management on Irish National Roads

    OpenAIRE

    Feighan, Kieran; McGowan, Ray; Casey, Tom; O’Sullivan, Andrew

    2015-01-01

    The Irish National pavement network is Ireland’s strategic road network consisting of over 5,300 centreline kilometres of road and is managed by the National Roads Authority (NRA). There is a very significant variation across the network under a variety of headings, including pavement construction, pavement age, carriageway width, lane width, geometric design and traffic volumes carried. A large proportion of the network consists of “legacy” roads that have evolved from historic routes that a...

  10. Permeability testing of drilling core sample from pavement

    Institute of Scientific and Technical Information of China (English)

    Suda WANG; Zhengguang TANG; Xiaojun NING; Peiguan WU; Pingyi XING

    2008-01-01

    The permeability coefficient of pavement material is a very important parameter in designing the drainage of pavement structures and is also used to evalu-ate the quality of road construction. New equipment is used to measure the permeability coefficient of the pave-ment drilling core sample and relevant testing methods are introduced. Testing drilling core samples from a certain highway of Yunnan province has been proven to be feas-ible. The test results are also analyzed.

  11. In-Situ Behavior of Geosynthetically Stabilized Flexible Pavement

    OpenAIRE

    Appea, Alexander Kwasi

    1997-01-01

    The purpose of a geotextile separator beneath a granular base, or subbase in a flexible pavement system is to prevent the road aggregate and the underlying subgrade from intermixing. It has been hypothesized that in the absence of a geotextile, intermixing between base course aggregate and soft subgrade occurs. Nine heavily instrumented flexible pavement test sections were built in Bedford County Virginia to investigate the benefits of geosynthetic stabilization in flexible pavements. ...

  12. Pavement Response to Variable Tyre Pressure of Heavy Vehicles

    OpenAIRE

    Arshad Ahmad Kamil; Haron Hairol Anuar; Abd Rahman Zanariah; Abdul Halim A.G.

    2016-01-01

    In recent years, the effect of overinflated tyre pressure and increased heavy vehicles’ axle load on flexible pavements has become a subject of great concern because of the higher stress levels induced and damage caused to road pavements. This paper aims to evaluate the effect of variable tyre inflation pressures (using actual tyre contact/footprint area) to determine the responses of flexible pavement. A full scale experiment was conducted on a heavy vehicle with 1:1:2 axle configuration, 10...

  13. Long-Term Field Performance of Pervious Concrete Pavement

    OpenAIRE

    Aleksandra Radlińska; Andrea Welker; Kathryn Greising; Blake Campbell; David Littlewood

    2012-01-01

    The work described in this paper provides an evaluation of an aged pervious concrete pavement in the Northeastern United States to provide a better understanding of the long-lasting effects of placement techniques as well as the long-term field performance of porous pavement, specifically in areas susceptible to freezing and thawing. Multiple samples were taken from the existing pavement and were examined in terms of porosity and unit weight, compressive and splitting tensile strength, and th...

  14. A study of bituminous pavements to determine a correlation between pavement structure designs and tripping of asphalt cement

    Science.gov (United States)

    Barton, B. R.

    1984-03-01

    After detecting a few cases of stripping of asphalt cement from the aggregate in bituminous pavement, there was concern that stripping might be a widespread problem in the state. It is agreed that water is the cause of stripping, and it was the opinion of some that pavements on granular bases would be less likely to strip because of supposedly better drainage characteristics. Differently designed pavement structures in all areas of the state were investigated to determine if there is a correlation between base and pavement design and stripping. Stripping was not as widespread as had been feared and there was less stripping in fulldepth bituminous base and pavement constructed over a lime-treated subgrade than in pavements constructed oer granular bases. This was contrary to what some had theorized.

  15. Environmentally friendly pavements: Results from noise measurements 2005-2008

    OpenAIRE

    Berge, Truls Svenn; Haukland, Frode; Ustad, Asbjørn

    2009-01-01

    CPX-measurements (tyre A) have been performed on a wide range of ordinary dense Norwegian road pavements and special test pavements, as part of the R&D project “Environmental friendly pavements” initiated by the Norwegian Public Roads Administration. The following conclusions can be made from the investigation:- New dense asphalt concrete pavements can give a tyre/road noise level (CPX) of 4-8 dB(A) lower noise level, compared to a chosen reference level for a pavement of type AC 0/11 and SMA...

  16. 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.

  17. 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.

  18. "Full-Scale Testing of Pavement Response"

    DEFF Research Database (Denmark)

    Ullidtz, Per; Ekdahl, Peter

    1998-01-01

    -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.......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...

  19. Treatment of acute variceal bleeding

    DEFF Research Database (Denmark)

    Bendtsen, Flemming; Krag, Aleksander Ahm; Møller, Søren

    2008-01-01

    The management of variceal bleeding remains a clinical challenge with a high mortality. Standardisation in supportive and new therapeutic treatments seems to have improved survival within the last 25 years. Although overall survival has improved in recent years, mortality is still closely related...

  20. 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...

  1. Smart pavement sensor based on thermoelectricity power

    Science.gov (United States)

    Yu, Xiong; Zhang, Bin; Tao, Junliang; Liu, Zhen

    2010-04-01

    The aging infrastructure requires a proactive strategy to ensure their functionality and performance. Innovative sensors are needed to develop infrastructures that are intelligent and adaptive. A power supply strategy is among the crucial components to reduce the instrument cost and to ensure the long term function of these embedded sensors. This paper introduces the results of a preliminary study on using thermo-electricity generation to power sensors. This presents an innovative strategy for long term monitoring of pavement performance.

  2. COMPARISON OF PAVEMENT STRUCTURES IN TUNNELS

    OpenAIRE

    Rimac, Ivan; Šimun, Miroslav; Dimter, Sanja

    2014-01-01

    Tunnels pose many fire risks. It is difficult to fight fires in tunnels due to their limited accessibility, the quantity of smoke, and high thermal radiation. Temperatures in tunnel fires can reach 1000 °C, and these fires can spread quickly and persist for long periods, the longest recorded in Europe lasting 53 h. The main requirements of tunnel pavement structures are driving safety and comfort, as well as low construction and maintenance costs. Choosing between using concrete or asphalt pa...

  3. Performance of Drained and Undrained Flexible Pavement Structures Under Wet Conditions Test Data From Accelerated Pavement Test Section 543-Drained

    OpenAIRE

    Harvey, John; Bejarano, Manuel O.; Ali, Abdikarim; Russo, Mark; Mahama, David; Hung, Dave; Preedonant, Pitipat

    2004-01-01

    This report is the first in a series of four reports that describe the results of accelerated pavement tests on full-scale pavements with “wet†base conditions at the Pavement Research Center, located at the University of California Berkeley Richmond Field Station (RFS). The report contains a summary of the results and associated analysis of a pavement section comprised of three lifts of asphalt concrete, an asphalt treated permeable base (ATPB) layer, and untreated aggregate base layers o...

  4. New structural systems for zero-maintenance pavements. Volume 2: Analysis of anchored pavements using ANSYS

    Science.gov (United States)

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

    1980-08-01

    A set of procedures to evaluate the response of an anchored pavement subjected to vehicle static loads, moisture variation in the subgrade, and/or temperature variation through the surface of the pavement is presented. These procedures include two computer programs known as FEMESH and ANSYS. The FEMESH program generates rectangular meshes in either a two or three dimensional coordinate system for any prespecified number and spacing of nodes. The ANSYS program evaluates the stresses, strains, and the deflections at all elements in each material included in the analytical model.

  5. An unusual cause of gastrointestinal bleed

    Directory of Open Access Journals (Sweden)

    C K Adarsh

    2014-01-01

    Full Text Available Gastrointestinal (GI bleed often brings the patient to the emergency medical service with great anxiety. Known common causes of GI bleed include ulcers, varices, Mallory-Weiss among others. All causes of GI bleed should be considered however unusual during the evaluation. Aortoenteric fistula (AEF is one of the unusual causes of GI bleed, which has to be considered especially in patients with a history of abdominal surgery in general and aortic surgery in particular.

  6. An analysis of pavement heat flux to optimize the water efficiency of a pavement-watering method

    International Nuclear Information System (INIS)

    Pavement-watering as a technique of cooling dense urban areas and reducing the urban heat island effect has been studied since the 1990's. The method is currently considered as a potential tool for and climate change adaptation against increasing heat wave intensity and frequency. However, although water consumption necessary to implement this technique is an important aspect for decision makers, optimization of possible watering methods has only rarely been conducted. An analysis of pavement heat flux at a depth of 5 cm and solar irradiance measurements is proposed to attempt to optimize the watering period, cycle frequency and water consumption rate of a pavement-watering method applied in Paris over the summer of 2013. While fine-tuning of the frequency can be conducted on the basis of pavement heat flux observations, the watering rate requires a heat transfer analysis based on a relation established between pavement heat flux and solar irradiance during pavement insolation. From this, it was found that watering conducted during pavement insolation could be optimized to 30-min cycles and water consumption could be reduced by more than 80% while reducing the cooling effect by less than 13%. - Highlights: • The thermal effects of pavement-watering were investigated in Paris, France. • Pavement-watering was found to significantly affect pavement heat flux 5 cm deep. • When insolated, a linear relation was found between heat flux and solar radiation. • Pavement-watering did not alter its slope, but introduced a negative intercept. • Subsequent improvements of the watering period, frequency and rate are proposed

  7. 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...

  8. Nutrient Infiltrate Concentrations from Three Permeable Pavement Types

    Science.gov (United States)

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha...

  9. 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,…

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

    Science.gov (United States)

    Cai, Yingchun; Zhang, Yamin

    2011-06-01

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

  11. Management of severe perioperative bleeding

    DEFF Research Database (Denmark)

    Kozek-Langenecker, Sibylle A; Afshari, Arash; Albaladejo, Pierre;

    2013-01-01

    The aims of severe perioperative bleeding management are three-fold. First, preoperative identification by anamesis and laboratory testing of those patients for whom the perioperative bleeding risk may be increased. Second, implementation of strategies for correcting preoperative anaemia...... with an assessment of the quality of the evidence in order to allow anaesthetists throughout Europe to integrate this knowledge into daily patient care wherever possible. The Guidelines Committee of the European Society of Anaesthesiology (ESA) formed a task force with members of scientific subcommittees......-sectional surveys were selected. At the suggestion of the ESA Guideline Committee, the Scottish Intercollegiate Guidelines Network (SIGN) grading system was initially used to assess the level of evidence and to grade recommendations. During the process of guideline development, the official position of the ESA...

  12. Shakedown analysis of anisotropic asphalt concrete pavements with clay subgrade

    Energy Technology Data Exchange (ETDEWEB)

    Boulbibane, M.; Collins, I.F. [Auckland Univ., Auckland (New Zealand). Dept. of Engineering Science; Weichert, D. [RWTH-Aachen Inst. of General Mechanics, Aachen (Germany); Raad, L. [Alaska-Fairbanks Univ., Fairbanks, AK (United States). Transportation and Research Centre

    2000-08-04

    A mathematical model has been presented which can predict the effect of inherent anisotropic cohesion on the long-term behaviour of multilayered pavements. The model is based on the lower bound theorem of shakedown analysis and makes allowances for variations of soil strength with direction. Pavements operating above the critical shakedown load exhibit plastic strains under long term repeated loading conditions and eventually result in deep ruts. This model was used to examine the influence of subgrade properties on the shakedown behaviour of two-layer pavement systems consisting of an asphalt concrete layer and a granular base over a clay subgrade. The shakedown load for pavements under repeated loadings was estimated and the effects of variables such as temperature, asphalt thickness, stiffness and strength were determined. The materials in the various layers of the pavement were modeled as elastic-plastic Mohr-Coulomb materials. 38 refs., 3 tabs., 5 figs.

  13. Monitoring asphalt pavement damages using remote sensing techniques

    Science.gov (United States)

    Mettas, Christodoulos; Themistocleous, Kyriacos; Neocleous, Kyriacos; Christofe, Andreas; Pilakoutas, Kypros; Hadjimitsis, Diofantos

    2015-06-01

    One of the main issues in the maintenance plans of road agencies or governmental organizations is the early detection of damaged asphalt pavements. The development of a smart and non-destructive systematic technique for monitoring damaged asphalt pavements is considered a main priority to fill this gap. During the 1970's, remote sensing was used to map road surface distress, while during the last decade, remote sensing became more advanced, thereby assisting in the evolution of the identification and mapping of roads. Various techniques were used in order to explore condition, age, weaknesses and imperfections of asphalted pavements. These methods were fairly successful in the classification of asphalted surfaces and in the detection of some of their characteristics. This paper explores the state of the art of using remote sensing techniques for monitoring damaged pavements and some typical spectral profiles of various asphalt pavements in Cyprus area acquired using the SVC1024 field spectroradiometer.

  14. Role of videocapsule endoscopy for gastrointestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    Cristina Carretero; Ignacio Fernandez-Urien; Maite Betes; Miguel Mu(n)oz-Navas

    2008-01-01

    Obscure gastrointestinal bleeding (OGIB) is defined as bleeding of an unknown origin that persists or recurs after negative initial upper and lower endoscopies.Several techniques,such as endoscopy,arteriography,scintigraphy and barium radiology are helpful for recognizing the bleeding source;nevertheless,in about 5%-10% of cases the bleeding lesion cannot be determined.The development of videocapsule endoscopy (VCE) has permitted a direct visualization of the small intestine mucosa.We will analyze those techniques in more detail.The diagnostic yield of CE for OGIB varies from 38% to 93%,being in the higher range in those cases with obscure-overt bleeding.

  15. Scintigraphic diagnosis of lower GI bleeding

    International Nuclear Information System (INIS)

    Abdominal scintigraphy with 99mTc HSA, 99mTc Sn colloid, or 99mTc RBC was performed in 28 patients with melena to detect bleeding and determine the bleeding site in the lower gastrointestinal tract. Active bleedings and/or vascular lesions were identified in 16 patients. They were proved by antiography, endoscopy or barium enema in 14. We concluded that scintigraphy was an accurate and effective method to detect the bleeding and determine the bleeding site in the lower gastrointestinal tract. (author)

  16. Pavement structure mechanics response of flexible on semi-flexible overlay that based on the old cement concrete pavement damage

    Directory of Open Access Journals (Sweden)

    Jiang Ruinan

    2015-01-01

    Full Text Available The old cement pavement damage status directly affect the design of the paving renovation. Based on the state of the old road investigation, combined with the research data at home and abroad, use the control index that average deflection, deflection value and CBR value to determine the reasonable time to overlay. Draw up the typical pavement structure according to the principle of combination of old cement pavement overlay structure design, and calculated that the tensile stress and shear stress in asphalt layer ,semi-flexible layer and the tensile in the old cement pavement adopting BISA3.0 statics finite element analysis model when modulus in the old road was diminishing. Use the computed result to analyses the influence of old road damage condition the influence of pavement structure.

  17. Bleeding

    Science.gov (United States)

    ... NY: McGraw-Hill; 2004:chap 251. Lammers RL. Principles of wound management. In: Roberts JR, Hedges JR, eds. Roberts: Clinical ... 2009:chap 39. Simon BC, Hern HG. Wound management principles. In: Marx JA, Hockberger RS, Walls RM, et ...

  18. Pavement Pre- and Post-Treatment Performance Models Using LTPP Data

    OpenAIRE

    Lu, Pan; Tolliver, Denver

    2012-01-01

    This paper determines that pavement performance in International Roughness Index (IRI) is affected by exogenous interventions such as pavement age, precipitation level, freeze-thaw level, and lower level preservation maintenance strategies. An exponential function of pavement age was used to represent pavement IRI performance curves. Moreover, this paper demonstrates a method which calculates short-term post-pavement performance models from maintenance effect models and pre-treatment performa...

  19. 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.

  20. Tire Footprint Affects Hydroplaning On Wet Pavement

    Science.gov (United States)

    Yager, Thomas J.

    1989-01-01

    Recent investigations of tire hydroplaning at highway speeds reveal, in addition to inflation pressure, tire-footprint aspect ratio (FAR), defined as width divided by length of tire surface in contact with pavement, significantly influences speed at which dynamic hydroplaning begins. Tire speeds and forces developed during tests of up to 65 mi/h (105 km/h) were monitored on flooded test surface to identify development of hydroplaning. Study focused on automotive tires because FAR's of automotive tires vary more than those of aircraft tires.

  1. Survival Analysis of Fatigue and Rutting Failures in Asphalt Pavements

    Directory of Open Access Journals (Sweden)

    Pabitra Rajbongshi

    2016-01-01

    Full Text Available Fatigue and rutting are two primary failure mechanisms in asphalt pavements. The evaluations of fatigue and rutting performances are significantly uncertain due to large uncertainties involved with the traffic and pavement life parameters. Therefore, deterministically it is inadequate to predict when an in-service pavement would fail. Thus, the deterministic failure time which is known as design life (yr of pavement becomes random in nature. Reliability analysis of such time (t dependent random variable is the survival analysis of the structure. This paper presents the survival analysis of fatigue and rutting failures in asphalt pavement structures. It is observed that the survival of pavements with time can be obtained using the bathtub concept that contains a constant failure rate period and an increasing failure rate period. The survival function (S(t, probability density function (pdf, and probability distribution function (PDF of failure time parameter are derived using bathtub analysis. It is seen that the distribution of failure time follows three parametric Weibull distributions. This paper also works out to find the most reliable life (YrR of pavement sections corresponding to any reliability level of survivability.

  2. 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.

  3. Evaluation of accelerated deterioration in NAPTF flexible test pavements

    Institute of Scientific and Technical Information of China (English)

    Kasthurirangan GOPALAKRISHNAN

    2008-01-01

    Previous research studies have successfully demonstrated the use of artificial neural network(ANN)models for predicting critical structural responses and layer moduli of highway flexible pavements.The primary objective of this study was to develop an ANN-based approach for backcalculation of pavement moduli based on heavy weight deflectometer(HWD)test data,especially in the analysis of airport flexible pavements subjected to new generation aircraft(NGA).Two medium-strength subgrade flexible test sections,at the National Airport Pavement Test Facility(NAPTF),were modeled using a finite element(FE) based pavement analysis program,which can consider the non-linear stress-dependent behavior of pavement geomaterials.A multi-layer,feed-forward network which uses an error-backpropagation algorithm was trained to approximate the HWD backcalculation function using the FE program generated synthetic database.At the NAPTF,test sections were subjected to Boeing 777 (B777)trafficking on one lane and Boeing 747(B747)trafficking on the other lane using a test machine.To monitor the effect of traffic and climatic variations on pavement structural responses.HWD tests were conducted on the traffieked lanes and on the untraffieked centerline of test sections as trafficking progressed.The trained ANN models were successfully applied on the actual HWD test data acquired at the NAPTF to predict the asphalt concrete moduli and non-1inear subgrade moduli of the medium-strength subgrade flexible test sections.

  4. Automated management for pavement inspection system (AMPIS)

    Science.gov (United States)

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

    2003-08-01

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

  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...

  6. Adaptation of AASHTO Pavement Design Guide for Local Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Hajek, J.J. [Applied Research Associates Inc., Toronto, ON (Canada)

    2001-07-01

    The methodology used to adapt the 1993 AASHTO Guide for Design of Pavement Structures to Ontario conditions was described. The guide expresses the effect of traffic loads on pavement performance using the concept of axle Load Equivalency Factors (LEF). LEF is regarded as a pavement damage factor assigned to each specific load and axle configuration. The size of LEF is related to the damage that is expected to occur from a standard load of 80 kN carried by a single axle with dual tires. The factors are summarized to yield the number of Equivalent Single Axle Loads (ESALs) a pavement is expected to sustain during its life. A summary was also provided of the additional work done to prepare for the transition to the proposed mechanistically-based 2002 AASHTO Guide. The paper focused only on the design of flexible pavements in terms of load characterization using equivalent single axle loads along with axle load spectra, below grade and material characterization, plus initial and terminal serviceability and reliability. The AASHTO Guide uses two parameters to deal with design reliability: design reliability level and overall standard deviation. Data collected on Ontario highway pavements and materials was used for assessing the design inputs. Other data was also collected from research and development studies, laboratory experiments, and from a survey of experienced pavement design engineers. The end result was a new grouping of Ontario soils for pavement design, recommended values for the resilient modulus of below grade soils, recommendations for structural layer coefficients for Ontario pavement materials and recommendations for the initial pavement serviceability based on Ontario smoothness specifications. Results of calibration and verification processes indicate that for new flexible pavements, the AASHTO-Ontario model is in good agreement with the observed results. It was recommended that the calibration and verification of the AASHTO-Ontario model should be a

  7. Research on Alkaline Filler Flame-Retarded Asphalt Pavement

    Institute of Scientific and Technical Information of China (English)

    HU Shuguang; ZHANG Houji; WANG Jiaolan

    2006-01-01

    Used as flame retardant of tunnel asphalt pavement, organic bromides produce a large amount of poisons and smoke in construction and flame retardation stage. The alkaline filler was found to replace mineral filler, and the flame-retarded asphalt mixtures were produced. Experimental results show that these asphalt mixtures are smoke restrained; the performances and construction technology of asphalt pavement are not influenced; also the alkaline filler is of low-price. So this kind of flame-retarded asphalt mixtures is suitable for tunnel pavement.

  8. New approach for calculating permanent deformation in asphalt pavement

    Institute of Scientific and Technical Information of China (English)

    TAN Yi-qiu; CHEN Feng-chen; LIU Hao; SU Xin; DONG Ze-jiao; DONG Yu-ming

    2010-01-01

    A new approach using the Fiber Bragg Grating(FBG)sensor and viscoelastic model to monitor and analyze the internal strain and temperature of asphalt pavement is proposed.Some parameters including peak strain,temperature and loading time were calculated with the application of multi-dimensional sensors group.These parameters were incorporated with viscoelastic model of five units to evaluate the permanent deformation of pavement.An application example was conducted,and the results show that it is feasible to analyze and calculate the permanent deformation of pavement structures with FBG sensors.

  9. Sandostatin therapy of acute oesophageal variceal bleeding.

    Science.gov (United States)

    McKee, R F

    1993-01-01

    This communication deals with the emergency control of variceal bleeding rather than the prevention of rebleeding. The current main options of oesophageal tamponade, emergency sclerotherapy and drug therapy are discussed, with particular reference to the use of somatostatin. Sandostatin (Sandoz, Basel), a synthetic long-acting somatostatin analogue, was found to reduce transhepatic venous gradient by 30% with no effect on systemic haemodynamics in a study of 16 stable cirrhotic patients. In a trial comparing intravenous infusion of Sandostatin (SMS) to oesophageal tamponade (OT) in active variceal bleeding, 18 of 20 bleeds in the SMS group and 19 of 20 bleeds in the OT group were controlled at 4 h. Ten in the SMS group and 14 in the OT group had no further bleeding during the 48-hour study period. Thus SMS may be useful in the temporary control of active variceal bleeding. PMID:8359565

  10. Cost-Effective Pavement Performance Management of Indiana's Enhanced National Highway System through Strategic Modification of the Pavement Rehabilitation Treatment Trigger Values

    OpenAIRE

    Noureldin, Menna; Fricker, Jon D; Sinha, Kumares C.

    2015-01-01

    Cost-Effective Pavement Performance Management of Indiana's Enhanced National Highway System through Strategic Modification of the Pavement Rehabilitation Treatment Trigger Values Presented during Session 3: Policy and Funding, moderated by Magdy Mikhail, at the 9th International Conference on Managing Pavement Assets (ICMPA9) in Alexandria, VA. Includes conference paper and PowerPoint slides.

  11. [Diagnosis and therapy of bleeding in ENT].

    Science.gov (United States)

    Schulz, T; Eßer, D

    2013-12-01

    Bleeding in the oral cavity, nose or ear are common events in the daily routine of ENT specialists. Apart from trivial cases that often get outpatient treatment, there are numerous cases of serious bleeding that require stationary treatment and if necessary, an operative or interventional therapy. In the following section the most frequent types of bleeding, their diagnosis and therapy will be explained. PMID:24285208

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

    Science.gov (United States)

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

    1980-08-01

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

  13. Cyclical rectal bleeding in colorectal endometriosis.

    Science.gov (United States)

    Levitt, M D; Hodby, K J; van Merwyk, A J; Glancy, R J

    1989-12-01

    Three case reports of cyclical rectal bleeding in endometriosis affecting rectum and sigmoid colon emphasize the close relationship between such cyclical bleeding and intestinal endometriosis. The cause of bleeding, however, is still unclear. The predilection of endometriotic deposits for the outer layers of the bowel wall suggests that mucosal involvement is not a prerequisite for rectal bleeding. The frequent absence of identifiable intramural haemorrhage casts doubt on the premise that intestinal endometriotic deposits 'menstruate'. The cause may simply be a transient tear in normal mucosa due to swelling of an underlying endometriotic deposit at the time of menstruation. PMID:2597100

  14. A diagnostic approach to mild bleeding disorders.

    Science.gov (United States)

    Boender, J; Kruip, M J H A; Leebeek, F W G

    2016-08-01

    Mild inherited bleeding disorders are relatively common in the general population. Despite recent advances in diagnostic approaches, mild inherited bleeding disorders still pose a significant diagnostic challenge. Hemorrhagic diathesis can be caused by disorders in primary hemostasis (von Willebrand disease, inherited platelet function disorders), secondary hemostasis (hemophilia A and B, other (rare) coagulant factor deficiencies) and fibrinolysis, and in connective tissue or vascular formation. This review summarizes the currently available diagnostic methods for mild bleeding disorders and their pitfalls, from structured patient history to highly specialized laboratory diagnosis. A comprehensive framework for a diagnostic approach to mild inherited bleeding disorders is proposed. PMID:27208505

  15. Effect of Pavement Conditions on Rolling Resistance

    Directory of Open Access Journals (Sweden)

    Mr.Dipanjan Mukherjee

    2014-07-01

    Full Text Available Rolling resistance is the force acting on a vehicle over a full journey. It is generated by the hysteresis of tyre and pavement. Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement of the wheel, roadbed, etc. is recovered when the pressure is removed. A hysteresis phenomenon can be observed when viscoelastic materials undergo a load-then-unload process. A typical hysteresis curve of viscoelastic material can be found. The shadow area enclosed by the hysteresis loop represents energy loss. A characteristic of a deformable material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits hysteresis. As the tire rotates under the weight of the vehicle, it experiences repeated cycles of deformation and recovery, and it dissipates the hysteresis energy loss as heat. Hysteresis is the main cause of energy loss associated with rolling resistance and is attributed to the viscoelastic characteristics of the rubber. Materials that have a large hysteresis effect, such as rubber, which bounce back slowly, exhibit more rolling resistance than materials with a small hysteresis effect that bounce back more quickly and more completely, such as steel or silica. Low rolling resistance tires typically incorporate silica in place of carbon black in their tread compounds to reduce low-frequency hysteresis without compromising traction. Note that railroads also have hysteresis in the roadbed structure. Like the fuel consumption, rolling resistance also has a significant relationship with velocity. experiment has shown that, for a 32-tonn goods vehicle, rolling resistance contributes about 70% of total drag when driven at 50km/h and about 37% at 100km/h. An important issue which should not

  16. Long-Term Field Performance of Pervious Concrete Pavement

    Directory of Open Access Journals (Sweden)

    Aleksandra Radlińska

    2012-01-01

    Full Text Available The work described in this paper provides an evaluation of an aged pervious concrete pavement in the Northeastern United States to provide a better understanding of the long-lasting effects of placement techniques as well as the long-term field performance of porous pavement, specifically in areas susceptible to freezing and thawing. Multiple samples were taken from the existing pavement and were examined in terms of porosity and unit weight, compressive and splitting tensile strength, and the depth and degree of clogging. It was concluded that improper placement and curing led to uneven pavement thickness, irregular pore distribution within the pervious concrete, and highly variable strength values across the site, as well as sealed surfaces that prevented infiltration.

  17. 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...

  18. Optical fiber feasibility study in Accelerated Pavement Testing facility

    OpenAIRE

    Bueche, N.; Rychen, P.; Dumont, A.-G.; Santagata, E.

    2009-01-01

    The presented research has been carried out within the European project Intelligent Roads (INTRO). The major objective followed was to assess the potential of optical fiber for pavement monitoring in comparison with classical strain gauges. Thus, both measurement devices have been tested under the same conditions in a full scale Accelerated Pavement Testing (APT) at LAVOC. This facility allows the user to control different parameters such as loading configuration and temperature and, as a mat...

  19. Evaluation of pavement skid resistance using high speed texture measurement

    Directory of Open Access Journals (Sweden)

    Jay N. Meegoda

    2015-12-01

    Full Text Available Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth (MPD or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which also causes disruption of traffic in use. In this research skid numbers and MPD from 5 new asphalt pavements and 4 old asphalt pavements were collected using a locked wheel skid trailer and a vehicle mounted laser. Using the data collected, a correlation between the skid number (SN40R collected by locked wheel skid tester and the texture data or MPD collected by a vehicle mounted laser operating at highway speeds was developed. The proposed correlation for new pavements was positive for MPD values less than 0.75 mm to reach a peak SN40R value, then there was a negative correlation as the MPD increases until the MPD value was equal to 1.1 mm and beyond the MPD value of 1.1 mm to the maximum value of 1.4 mm, SN40R value remained almost constant. There were significant data scatter for the MPD value of 0.8 mm. To explain these results, water film thickness during the friction test was calculated and the critical MPD was defined. The effect of sealed water pool on the SN40R was discussed. The test result showed a similar trend for older asphalt pavements, but with lower SN40R values due to the polishing of pavement micro-texture by traffic. Hence, a reduction factor was proposed for older pavements based on cumulative traffic volume for the above correlation to predict the skid resistance of older pavements.

  20. 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...

  1. Visualizing Pavement Management Data at the Project Level

    OpenAIRE

    Rydholm, Timothy C.; Luhr, David R.

    2015-01-01

    As a Pavement Management System increases in maturity, so does the amount of information powering it. As the level of information grows, efficiently communicating the data becomes difficult. The Washington State Department of Transportation (WSDOT) has a long history of collecting and storing data that is electronically accessible and referenced against a Linear Referencing System (LRS). This data includes pavement surveys, contracts , capital projects, roadway configuration, maintenance acti...

  2. Field environmental evaluation plan for sulfur use in pavements

    Science.gov (United States)

    Saylak, D.; Deuel, L. E.; Izatt, J. O.; Jacobs, C.; Zahray, R.; Ham, S.

    1982-07-01

    The use of sulfur in highway paving mixtures is discussed. The evaluation procedures deal with the safety and environmental aspects of storage and handling, formulation, construction, operation and maintenance of highway pavements containing sulfur, including the possible generation of noxious and abnoxious fumes, dust and gases. Methods and equipment for monitoring potential emissions and pollutants are recommended and safety practices for the handling of sulfur and sulfur-modified asphalt mixtures and pavements are discussed.

  3. Application of surplus and waste materials in roads pavement making

    OpenAIRE

    S.M. Mousavi; Fazli, A. H.; Rouzmehr, F.

    2011-01-01

    Nowadays there are a lot of problems about surpluses and debris made by humans all around the world. Lots of these surpluses seriously harm our natural environment. Reuse of this kind of materials in other processes like building constructions or pavement help our natural environment in every aspect. Asphalt concrete is the main part of pavements in most parts of the world with an increasing rate of production in need of more ways and roads. In this paper we will provide...

  4. Factors Associated With Major Bleeding Events

    Science.gov (United States)

    Goodman, Shaun G.; Wojdyla, Daniel M.; Piccini, Jonathan P.; White, Harvey D.; Paolini, John F.; Nessel, Christopher C.; Berkowitz, Scott D.; Mahaffey, Kenneth W.; Patel, Manesh R.; Sherwood, Matthew W.; Becker, Richard C.; Halperin, Jonathan L.; Hacke, Werner; Singer, Daniel E.; Hankey, Graeme J.; Breithardt, Gunter; Fox, Keith A. A.; Califf, Robert M.

    2014-01-01

    Objectives This study sought to report additional safety results from the ROCKET AF (Rivaroxaban Once-daily oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation). Background The ROCKET AF trial demonstrated similar risks of stroke/systemic embolism and major/nonmajor clinically relevant bleeding (principal safety endpoint) with rivaroxaban and warfarin. Methods The risk of the principal safety and component bleeding endpoints with rivaroxaban versus warfarin were compared, and factors associated with major bleeding were examined in a multivariable model. Results The principal safety endpoint was similar in the rivaroxaban and warfarin groups (14.9 vs. 14.5 events/100 patient-years; hazard ratio: 1.03; 95% confidence interval: 0.96 to 1.11). Major bleeding risk increased with age, but there were no differences between treatments in each age category (<65, 65 to 74, ≥75 years; pinteraction = 0.59). Compared with those without (n = 13,455), patients with a major bleed (n = 781) were more likely to be older, current/prior smokers, have prior gastrointestinal (GI) bleeding, mild anemia, and a lower calculated creatinine clearance and less likely to be female or have a prior stroke/transient ischemic attack. Increasing age, baseline diastolic blood pressure (DBP) ≥90 mm Hg, history of chronic obstructive pulmonary disease or GI bleeding, prior acetylsalicylic acid use, and anemia were independently associated with major bleeding risk; female sex and DBP <90 mm Hg were associated with a decreased risk. Conclusions Rivaroxaban and warfarin had similar risk for major/nonmajor clinically relevant bleeding. Age, sex, DBP, prior GI bleeding, prior acetylsalicylic acid use, and anemia were associated with the risk of major bleeding. (An Efficacy and Safety Study of Rivaroxaban With Warfarin for the Prevention of Stroke and Non-Central Nervous System Systemic Embolism in Patients With Non

  5. Diagnostic Strategies for Postmenopausal Bleeding

    Directory of Open Access Journals (Sweden)

    M. C. Breijer

    2010-01-01

    Full Text Available Postmenopausal bleeding (PMB is a common clinical problem. Patients with PMB have 10%–15% chance of having endometrial carcinoma and therefore the diagnostic workup is aimed at excluding malignancy. Patient characteristics can alter the probability of having endometrial carcinoma in patients with PMB; in certain groups of patients the incidence has been reported to be as high as 29%. Transvaginal sonography (TVS is used as a first step in the diagnostic workup, but different authors have come to different conclusions assessing the accuracy of TVS for excluding endometrial carcinoma. Diagnostic procedures obtaining material for histological assessment (e.g., dilatation and curettage, hysteroscopy, and endometrial biopsy can be more accurate but are also more invasive. The best diagnostic strategy for diagnosing endometrial carcinoma in patients with PMB still remains controversial. Future research should be focussed on achieving a higher accuracy of different diagnostic strategies.

  6. Use of lime cement stabilized pavement construction

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, M.A.; Raju, G.V.R.P. [JNTU College of Engineering, Kakinada (India). Dept. of Civil Engineering

    2009-08-15

    Expansive clay is a major source of heave induced structural distress. Swelling of expansive soils causes serious problems and produce damages to many structures. Many research organizations are doing extensive work on waste materials concerning the feasibility and environmental suitability. Fly ash, a waste by product from coal burning in thermal power stations, is abundant in India causing severe health, environmental and disposal problems. Attempts are made to investigate the stabilization process with model test tracks over expansive subgrade in flexible pavements. Cyclic plate load tests are carried out on the tracks with chemicals like lime and cement introduced in fly ash subbase laid on sand and expansive subgrades. Test results show that maximum load carrying capacity is obtained for stabilized fly ash subbase compared to untreated fly ash subbase.

  7. Pavement Response to Variable Tyre Pressure of Heavy Vehicles

    Directory of Open Access Journals (Sweden)

    Arshad Ahmad Kamil

    2016-01-01

    Full Text Available In recent years, the effect of overinflated tyre pressure and increased heavy vehicles’ axle load on flexible pavements has become a subject of great concern because of the higher stress levels induced and damage caused to road pavements. This paper aims to evaluate the effect of variable tyre inflation pressures (using actual tyre contact/footprint area to determine the responses of flexible pavement. A full scale experiment was conducted on a heavy vehicle with 1:1:2 axle configuration, 10 R 20 tyre size and attached trailer with constant axle load. Measurements were made for actual tyre-pavement contact area. KENPAVE linear elastic program was then used to analyse the effects of the measured actual tyre-pavement contact area and the results was compared using conventional circular tyre contact area. A comparative analysis was then made between the actual contact area and the conventional circular tyre contact area. It was found that high tyre inflation pressure produce smaller contact area, giving more detrimental effect on the flexible pavement. It was also found that the temperature of tyres when the heavy vehicles are operational give less significant impact on tyre inflation pressure for the Malaysian climate.

  8. Environmental assessment of pavement infrastructure: A systematic review.

    Science.gov (United States)

    Inyim, Peeraya; Pereyra, Jose; Bienvenu, Michael; Mostafavi, Ali

    2016-07-01

    Through a critical review and systematic analysis of pavement life cycle assessment (LCA) studies published over the past two decades, this study shows that the available information regarding the environmental impacts of pavement infrastructure is not sufficient to determine what pavement type is more environmentally sustainable. Limitations and uncertainties related to data, system boundary and functional unit definitions, consideration of use and maintenance phase impacts, are identified as the main reasons for inconsistency of reported results in pavement LCA studies. The study outcomes also highlight the need for advancement of knowledge pertaining to: (1) utilization of performance-adjusted functional units, (2) accurate estimation of use, maintenance, and end-of-life impacts, (3) incorporation of the dynamic and uncertain nature of pavement condition performance in impact assessment; (4) development of region-specific inventory data for impact estimation; and (5) consideration of a standard set of impact categories for comparison of environmental performance of different pavement types. Advancing the knowledge in these areas is critical in providing consistent and reliable results to inform decision-making toward more sustainable roadway infrastructure. PMID:27045541

  9. Noise emission of concrete pavement surfaces produced by diamond grinding

    Directory of Open Access Journals (Sweden)

    Jens Skarabis

    2015-04-01

    Full Text Available In Germany, diamond grinding is frequently used to improve the evenness and skid resistance of concrete pavement surfaces. Since diamond grinding has been observed to affect tyre/pavement noise emission favourably, the relationship among surface texture, concrete composition and noise emission of concrete pavement surfaces has been systematically investigated. The simulation program SPERoN was used in a parameter study to investigate the main factors which affect noise emission. Based on the results of the simulations, textured concrete surfaces were produced by using a laboratory grinding machine. As well as the composition of the concrete, the thickness and spacing of the diamond blades were varied. The ability of the textured surfaces to reduce noise emission was assessed from the texture characteristics and air flow resistance of textured surfaces measured in the laboratory. It was found that concrete composition and, in particular, the spacing of the blades affected the reduction in noise emission considerably. The noise emission behaviour of numerous road sections was also considered in field investigations. The pavement surfaces had been textured by diamond grinding during the last years or decades. The results show that diamond grinding is able to provide good, durable noise-reducing properties. Several new pavement sections were investigated using thicknesses and spacings of the blades similar to those used in the laboratory to optimize noise emission reduction. It is concluded that diamond grinding is a good alternative to exposed aggregate concrete for the production of low-noise pavement surfaces.

  10. Factors influencing PM 10 emissions from road pavement wear

    Science.gov (United States)

    Gustafsson, Mats; Blomqvist, Göran; Gudmundsson, Anders; Dahl, Andreas; Jonsson, Per; Swietlicki, Erik

    Accelerated pavement wear is one of the major environmental disadvantages of studded tyres in northern regions and results in increased levels of PM 10. Measurements of PM 10 in a road simulator hall have been used to study the influence of pavement properties, tyre type and vehicle speed on pavement wear. The test set-up included three different pavements (one granite and two quartzite with different aggregate sizes), three different tyre types (studded, non-studded, and summer tyres) and different speeds (30-70 km h -1). The results show that the granite pavement was more prone to PM 10 production compared to the quartzite pavements. Studded winter tyres yield tens of times higher PM 10 concentrations compared to non-studded winter tyres. Wear from summer tyres was negligible in comparison. It was also shown that wear is strongly dependent on speed; every 10 km h -1 increase yielded an increase of the PM 10 concentration of 680 μg m -3 in one of the simulator experiments.

  11. Numerical Analysis of Asphalt Pavements under Moving Wheel Loads

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The responses of the pavement in service are the basis for the design of the semi-rigid base course asphalt pavement.Due to the dynamic characteristics of wheel loads and the temperature loads,the dynamic response analysis is very significant.In this article, the dynamic analysis of asphalt pavement under moving wheel loads is carried out using finite element method coupled with non-reflective boundary method.The influences of the base modulus, thickness, the vehicle velocity, the tire pressure, and the contact condition at the interface are studied using parametric analysis.The results of numerical analysis show that it is not appropriate to simply increase the base modulus or thickness in the design.It would be beneficial if the base design is optimized synthetically.The increase of damping is also beneficial to the pavements because of the surface deflection and the stresses declination.Furthermore, the good contact condition at the interface results in good performance because it combines every layer of the pavement to work together.As overload aggravates the working condition of the pavement, it is not allowed.

  12. Urban pavement surface temperature. Comparison of numerical and statistical approach

    Science.gov (United States)

    Marchetti, Mario; Khalifa, Abderrahmen; Bues, Michel; Bouilloud, Ludovic; Martin, Eric; Chancibaut, Katia

    2015-04-01

    The forecast of pavement surface temperature is very specific in the context of urban winter maintenance. to manage snow plowing and salting of roads. Such forecast mainly relies on numerical models based on a description of the energy balance between the atmosphere, the buildings and the pavement, with a canyon configuration. Nevertheless, there is a specific need in the physical description and the numerical implementation of the traffic in the energy flux balance. This traffic was originally considered as a constant. Many changes were performed in a numerical model to describe as accurately as possible the traffic effects on this urban energy balance, such as tires friction, pavement-air exchange coefficient, and infrared flux neat balance. Some experiments based on infrared thermography and radiometry were then conducted to quantify the effect fo traffic on urban pavement surface. Based on meteorological data, corresponding pavement temperature forecast were calculated and were compared with fiels measurements. Results indicated a good agreement between the forecast from the numerical model based on this energy balance approach. A complementary forecast approach based on principal component analysis (PCA) and partial least-square regression (PLS) was also developed, with data from thermal mapping usng infrared radiometry. The forecast of pavement surface temperature with air temperature was obtained in the specific case of urban configurtation, and considering traffic into measurements used for the statistical analysis. A comparison between results from the numerical model based on energy balance, and PCA/PLS was then conducted, indicating the advantages and limits of each approach.

  13. Obstetric management of adolescents with bleeding disorders.

    Science.gov (United States)

    James, Andra H

    2010-12-01

    Adolescents with bleeding disorders who become pregnant must contend with the dual challenges of their bleeding disorder and their pregnancy. Adolescents are more likely to terminate a pregnancy than adult women, and when they do carry a pregnancy, they are more likely to deliver prematurely. Otherwise, they are at risk for the same complications that adult women with bleeding disorders experience, particularly bleeding complications postpartum. Since one half to two thirds of adolescent pregnancies are unplanned, issues related to reproduction should be addressed during routine visits with the pediatrician, hematologist or gynecologist. Girls who are at risk of being carriers for hemophilia A and B, severe von Willebrand disease, and other severe bleeding disorders should have their bleeding disorder status determined before they become pregnant. During pregnancy, a plan should be established to ensure that both mother and fetus deliver safely. Young women at risk for severe bleeding or at risk of having a severely affected infant should be referred for prenatal care and delivery to a center where, in addition to specialists in high-risk obstetrics, there is a hemophilia treatment center or a hematologist with expertise in hemostasis. Prior to delivery or any invasive procedures, young women at risk for severe bleeding should receive prophylaxis. Since administration of desmopressin may result in hyponatremia, whenever available, virally inactivated or recombinant clotting factor concentrates should be used for replacement as opposed to fresh frozen plasma or cryoprecipitate. PMID:20934895

  14. First trimester bleeding and maternal cardiovascular morbidity

    DEFF Research Database (Denmark)

    Lykke, Jacob A; Langhoff-Roos, Jens

    2012-01-01

    First trimester bleeding without miscarriage is a risk factor for complications later in the pregnancy, such as preterm delivery. Also, first trimester miscarriage has been linked to subsequent maternal ischemic heart disease. We investigated the link between maternal cardiovascular disease prior...... to and subsequent to first trimester bleeding without miscarriage....

  15. Transarterial embolization of acute intercostal artery bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Jae Ik; Park, Auh Whan; Lee, Seon Joo [Inje University College of Medicine, Busan (Korea, Republic of); Ko, Gi Young; Yoon, Hyun Ki [University of Ulsan College of Medicine, Seoul (Korea, Republic of); Yoon, Chang Jin [Seoul National University Bundang Hospital, Seongnam (Korea, Republic of); Shin, Tae Beom [Donga University College of Medicine, Busan (Korea, Republic of); Kim, Young Hwan [Kyimyung University School of Medicine, Daegu (Korea, Republic of)

    2005-09-15

    To report our experiences of transarterial embolization for acute intercostal artery bleeding. A retrospectively analysis of the causes, clinical manifestations, angiographic findings and transarterial embolization technique in 8 patients with acute intercostal artery bleeding, with a review of the anatomical basis. The causes of intercostal artery bleeding were iatrogenic and traumatic in 88 and 12% of cases, respectively. Active bleeding from the collateral intercostal or posterior intercostal arteries was angiographically demonstrated in 75 and 25% of cases, respectively. Transarterial embolization successfully achieved hemostasis in all cases. However, two patient with hypovolemic shock expired due to a massive hemothorax, despite successful transarterial embolization. Intercostal access should be performed through the middle of the intercostal space to avoid injury to the collateral intercostal artery. Transarterial embolization is an effective method for the control of intercostal artery bleeding.

  16. Update to permeable pavement research at the Edison Environmental Center - slides

    Science.gov (United States)

    Abstract: The EPA’s Urban Watershed Management Branch (UWMB) has been monitoring the permeable pavement demonstration site at the Edison Environmental Center, NJ since 2010. This site has three different types of permeable pavement including: interlocking concrete permeable...

  17. Update to Permeable Pavement Research at the Edison Environmental Center - abstract

    Science.gov (United States)

    Abstract The EPA’s Urban Watershed Management Branch (UWMB) has been monitoring the permeable pavement demonstration site at the Edison Environmental Center, NJ since 2010. This site has three different types of permeable pavement including: interlocking concrete permeable ...

  18. Genetic Optimization Method of Asphalt Pavement Based on Rutting and Cracking Control

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Nowadays asphalt pavement structure bearing is not the main subject for pursuers to study.Comparatively,the pavement performance is more important and emphasized.Based on this,rutting and cracking analysis is introduced into pavement optimization.A optimization model based on these two considerations is also established.The genetic algorithms (GAs) is adopted to solve the model.It is an intellective method.This research provides a new idea and technique for asphalt pavement structure optimization.

  19. Implementation of the AASHTO pavement design procedures into MULTI-PAVE.

    OpenAIRE

    Bekele, Abiy

    2011-01-01

    This thesis implements the empirical pavement design procedures for flexible as well as rigid pavement by American Association of State Highways and Transportation Officials (AASHTO) into two MATLAB modules of MULTI-PAVE. MULTI-PAVE was developed as a teaching tool that performs pavement thickness design for multiple design procedures using a common input file and a common output format. The AASHTO components were developed in accordance with the 1993 AASHTO Pavement Design Guide, and verifie...

  20. Comparison of Surface Characteristics of Hot-Mix Asphalt Pavement Surfaces at the Virginia Smart Road

    OpenAIRE

    Davis, Robin Michelle

    2001-01-01

    Pavement surface characteristics are important to both the safety of the pavement surface and the comfort of the drivers. As of yet, texture and friction measurements have not been incorporated into the design of pavement surfaces. Seven different wearing surface mixtures, placed at the Virginia Smart Road pavement facility, were studied over a one year time period for both friction and texture properties. A locked wheel skid trailer and a laser profilometer were used to assess the pavemen...

  1. Decision of National and Provincial Highway Asphalt Pavement Structure Based on Value Engineering

    OpenAIRE

    Yingwei Ren; Jingsong Shan

    2014-01-01

    It is important that decision of asphalt pavement structure requires overall considerations of the performance and financial investment. To have asphalt pavement structure fulfilling good reliability, the asphalt pavement structure decision was researched based on value engineering theory. According to the national and provincial highway investigation data in Shandong Province during the last decade, the asphalt pavement performance attenuation rules of traffic levels and asphalt layer thickn...

  2. Prediction of IRI in short and long terms for flexible pavements: ANN and GMDH methods

    NARCIS (Netherlands)

    Ziari, H.; Sobhani, J.; Ayoubinejad, J.; Hartmann, T.

    2015-01-01

    Prediction of pavement condition is one of the most important issues in pavement management systems. In this paper, capabilities of artificial neural networks (ANNs) and group method of data handling (GMDH) methods in predicting flexible pavement conditions were analysed in three levels: in 1 year,

  3. 78 FR 26847 - Including Specific Pavement Types in Federal-aid Highway Traffic Noise Analyses

    Science.gov (United States)

    2013-05-08

    ... Federal Highway Administration Including Specific Pavement Types in Federal-aid Highway Traffic Noise...: The FHWA requests input from stakeholders and interested parties on expanding the specific pavement... data from three pavement types: dense-graded asphaltic concrete (DGAC), open-graded asphaltic...

  4. 23 CFR 972.208 - Federal lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ... “Pavement Management Guide,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 972.208....208 Federal lands pavement management system (PMS). In addition to the requirements provided in §...

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

    Science.gov (United States)

    2011-10-28

    ... Federal Aviation Administration Notice to Manufacturers of Airport In-Pavement Stationary Runway Weather... of In-Pavement Stationary Runway Weather Information Systems. SUMMARY: Projects funded under the... Active or Passive In- Pavement Stationary Runway Weather Information Systems that meet the...

  6. 23 CFR 970.208 - Federal lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 970.208... Federal lands pavement management system (PMS). In addition to the requirements provided in § 970.204, the...) An inventory of the physical pavement features including the number of lanes, length, width,...

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

    Directory of Open Access Journals (Sweden)

    B. Matić

    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. Compressor bleed cooling fluid feed system

    Science.gov (United States)

    Donahoo, Eric E; Ross, Christopher W

    2014-11-25

    A compressor bleed cooling fluid feed system for a turbine engine for directing cooling fluids from a compressor to a turbine airfoil cooling system to supply cooling fluids to one or more airfoils of a rotor assembly is disclosed. The compressor bleed cooling fluid feed system may enable cooling fluids to be exhausted from a compressor exhaust plenum through a downstream compressor bleed collection chamber and into the turbine airfoil cooling system. As such, the suction created in the compressor exhaust plenum mitigates boundary layer growth along the inner surface while providing flow of cooling fluids to the turbine airfoils.

  9. Lower Gastrointestinal Bleeding in Chronic Hemodialysis Patients

    Directory of Open Access Journals (Sweden)

    Fahad Saeed

    2011-01-01

    Full Text Available Gastrointestinal (GI bleeding is more common in patients with chronic kidney disease and is associated with higher mortality than in the general population. Blood losses in this patient population can be quite severe at times and it is important to differentiate anemia of chronic diseases from anemia due to GI bleeding. We review the literature on common causes of lower gastrointestinal bleeding (LGI in chronic kidney disease (CKD and end-stage renal disease (ESRD patients. We suggest an approach to diagnosis and management of this problem.

  10. 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.

  11. 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

  12. Modeling of unsaturated granular materials in flexible pavements

    Directory of Open Access Journals (Sweden)

    Gu Fan

    2016-01-01

    Full Text Available The unsaturated granular material (UGM is found to exhibit the moisture-sensitive and stress-dependent nonlinear cross-anisotropic behaviour in flexible pavements. This paper aims at developing a finite element (FE model for pavement structure, which takes into account this behaviour of UGM. First, the Lytton model is employed to characterize the moisture-sensitive and stress-dependent behaviour of UGM, which incorporated a matric suction term to the existing stress-dependent constitutive model. The Lytton model is validated by the laboratory resilient modulus tests on the selected UGMs at different moisture contents. Second, the nonlinear cross-anisotropic constitutive equation of UGM is derived from the generalized Hooke’s Law. The coefficients of the constitutive model are determined by the rapid triaxial test. Third, a User-Defined Material (UMAT subroutine is developed to characterize this constitutive behaviour in the FE software ABAQUS. The UMAT subroutine adopts the secant stiffness approach with multiple damping factors. The UMAT subroutine is then implemented in the FE model of flexible pavement structures. The FE simulation results indicate the nonlinear cross-anisotropic model predicts greater pavement responses than the isotropic model. When the UGM is suction sensitive, it is found that the moisture content of UGM significantly affects the moduli distribution of base layer and the critical strains (i.e., tensile strain at the bottom of asphalt concrete, and compressive strains in base and subgrade layers of pavement structures.

  13. 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.

  14. Genetic analysis of bleeding disorders.

    Science.gov (United States)

    Edison, E; Konkle, B A; Goodeve, A C

    2016-07-01

    Molecular genetic analysis of inherited bleeding disorders has been practised for over 30 years. Technological changes have enabled advances, from analyses using extragenic linked markers to next-generation DNA sequencing and microarray analysis. Two approaches for genetic analysis are described, each suiting their environment. The Christian Medical Centre in Vellore, India, uses conformation-sensitive gel electrophoresis mutation screening of multiplexed PCR products to identify candidate mutations, followed by Sanger sequencing confirmation of variants identified. Specific analyses for F8 intron 1 and 22 inversions are also undertaken. The MyLifeOurFuture US project between the American Thrombosis and Hemostasis Network, the National Hemophilia Foundation, Bloodworks Northwest and Biogen uses molecular inversion probes (MIP) to capture target exons, splice sites plus 5' and 3' sequences and to detect F8 intron 1 and 22 inversions. This allows screening for all F8 and F9 variants in one sequencing run of multiple samples (196 or 392). Sequence variants identified are subsequently confirmed by a diagnostic laboratory. After having identified variants in genes of interest through these processes, a systematic procedure determining their likely pathogenicity should be applied. Several scientific societies have prepared guidelines. Systematic analysis of the available evidence facilitates reproducible scoring of likely pathogenicity. Documentation of frequency in population databases of variant prevalence and in locus-specific mutation databases can provide initial information on likely pathogenicity. Whereas null mutations are often pathogenic, missense and splice site variants often require in silico analyses to predict likely pathogenicity and using an accepted suite of tools can help standardize their documentation.

  15. Genetic analysis of bleeding disorders.

    Science.gov (United States)

    Edison, E; Konkle, B A; Goodeve, A C

    2016-07-01

    Molecular genetic analysis of inherited bleeding disorders has been practised for over 30 years. Technological changes have enabled advances, from analyses using extragenic linked markers to next-generation DNA sequencing and microarray analysis. Two approaches for genetic analysis are described, each suiting their environment. The Christian Medical Centre in Vellore, India, uses conformation-sensitive gel electrophoresis mutation screening of multiplexed PCR products to identify candidate mutations, followed by Sanger sequencing confirmation of variants identified. Specific analyses for F8 intron 1 and 22 inversions are also undertaken. The MyLifeOurFuture US project between the American Thrombosis and Hemostasis Network, the National Hemophilia Foundation, Bloodworks Northwest and Biogen uses molecular inversion probes (MIP) to capture target exons, splice sites plus 5' and 3' sequences and to detect F8 intron 1 and 22 inversions. This allows screening for all F8 and F9 variants in one sequencing run of multiple samples (196 or 392). Sequence variants identified are subsequently confirmed by a diagnostic laboratory. After having identified variants in genes of interest through these processes, a systematic procedure determining their likely pathogenicity should be applied. Several scientific societies have prepared guidelines. Systematic analysis of the available evidence facilitates reproducible scoring of likely pathogenicity. Documentation of frequency in population databases of variant prevalence and in locus-specific mutation databases can provide initial information on likely pathogenicity. Whereas null mutations are often pathogenic, missense and splice site variants often require in silico analyses to predict likely pathogenicity and using an accepted suite of tools can help standardize their documentation. PMID:27405681

  16. Dysfunctional Uterine Bleeding (DUB) (For Teens)

    Science.gov (United States)

    ... the body's hormones. Problems like compulsive exercise , not eating healthy foods, or too much stress can cause hormone changes. Some severe cases of AUB are caused by bleeding disorders such as von Willebrand disease . What Are the ...

  17. Fibrinogen concentrate for bleeding - a systematic review

    DEFF Research Database (Denmark)

    Lunde, J; Stensballe, J; Wikkelsø, A;

    2014-01-01

    Fibrinogen concentrate as part of treatment protocols increasingly draws attention. Fibrinogen substitution in cases of hypofibrinogenaemia has the potential to reduce bleeding, transfusion requirement and subsequently reduce morbidity and mortality. A systematic search for randomised controlled...

  18. Cough-induced Tracheobronchial Mucosal Bleeding.

    Science.gov (United States)

    Hira, Harmanjit Singh

    2011-01-01

    A 56-year-old man presented with moderate hemoptysis. It was preceded by a severe bout of cough. Flexible bronchoscopy showed diffuse tracheobronchial mucosal petechiae and bleeding. The patient was not suffering with any coagulopathies. He did not receive antiplatelet drugs. Hemoptysis resolved with cough suppressant. Subsequent bronchoscopy revealed the complete resolution of petechiae. The mechanism of bleeding after the bout of coughing is discussed. PMID:23169019

  19. Management of patients with ulcer bleeding.

    Science.gov (United States)

    Laine, Loren; Jensen, Dennis M

    2012-03-01

    This guideline presents recommendations for the step-wise management of patients with overt upper gastrointestinal bleeding. Hemodynamic status is first assessed, and resuscitation initiated as needed. Patients are risk-stratified based on features such as hemodynamic status, comorbidities, age, and laboratory tests. Pre-endoscopic erythromycin is considered to increase diagnostic yield at first endoscopy. Pre-endoscopic proton pump inhibitor (PPI) may be considered to decrease the need for endoscopic therapy but does not improve clinical outcomes. Upper endoscopy is generally performed within 24h. The endoscopic features of ulcers direct further management. Patients with active bleeding or non-bleeding visible vessels receive endoscopic therapy (e.g., bipolar electrocoagulation, heater probe, sclerosant, clips) and those with an adherent clot may receive endoscopic therapy; these patients then receive intravenous PPI with a bolus followed by continuous infusion. Patients with flat spots or clean-based ulcers do not require endoscopic therapy or intensive PPI therapy. Recurrent bleeding after endoscopic therapy is treated with a second endoscopic treatment; if bleeding persists or recurs, treatment with surgery or interventional radiology is undertaken. Prevention of recurrent bleeding is based on the etiology of the bleeding ulcer. H. pylori is eradicated and after cure is documented anti-ulcer therapy is generally not given. Nonsteroidal anti-inflammatory drugs (NSAIDs) are stopped; if they must be resumed low-dose COX-2-selective NSAID plus PPI is used. Patients with established cardiovascular disease who require aspirin should start PPI and generally re-institute aspirin soon after bleeding ceases (within 7 days and ideally 1-3 days). Patients with idiopathic ulcers receive long-term anti-ulcer therapy. PMID:22310222

  20. Abnormal uterine bleeding: a clinicohistopathological analysis

    OpenAIRE

    Anupamasuresh Y; Suresh YV; Prachi Jain*,

    2014-01-01

    Background: Abnormal uterine bleeding (AUB) is one of the most common problem for the patients and the gynecologists. It adversely effects on the quality of life and psychology of women. It is of special concern in developing country as it adds to the causes of anemia. Management of Abnormal Uterine Bleeding (AUB) is not complete without tissue diagnosis especially in perimenopausal and post-menopausal women. Histological characteristics of endometrial biopsy material as assessed by light mic...

  1. 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...... 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...

  2. Determination of Pavement Rehabilitation Activities through a Permutation Algorithm

    Directory of Open Access Journals (Sweden)

    Sangyum Lee

    2013-01-01

    Full Text Available This paper presents a mathematical programming model for optimal pavement rehabilitation planning. The model maximized the rehabilitation area through a newly developed permutation algorithm, based on the procedures outlined in the harmony search (HS algorithm. Additionally, the proposed algorithm was based on an optimal solution method for the problem of multilocation rehabilitation activities on pavement structure, using empirical deterioration and rehabilitation effectiveness models, according to a limited maintenance budget. Thus, nonlinear pavement performance and rehabilitation activity decision models were used to maximize the objective functions of the rehabilitation area within a limited budget, through the permutation algorithm. Our results showed that the heuristic permutation algorithm provided a good optimum in terms of maximizing the rehabilitation area, compared with a method of the worst-first maintenance currently used in Seoul.

  3. Application of Artificial Intelligence for Optimization in Pavement Management

    Directory of Open Access Journals (Sweden)

    Reus Salini

    2015-07-01

    Full Text Available Artificial intelligence (AI is a group of techniques that have quite a potential to be applied to pavement engineering and management. In this study, we developed a practical, flexible and out of the box approach to apply genetic algorithms to optimizing the budget allocation and the road maintenance strategy selection for a road network. The aim is to provide an alternative to existing software and better fit the requirements of an important number of pavement managers. To meet the objectives, a new indicator, named Road Global Value Index (RGVI, was created to contemplate the pavement condition, the traffic and the economic and political importance for each and every road section. This paper describes the approach and its components by an example confirming that genetic algorithms are very effective for the intended purpose.

  4. Design prediction of pavement skid resistance from laboratory tests

    Science.gov (United States)

    Parcells, W. H.; Metheny, T. M.; Maag, R. G.

    1980-08-01

    Methods for preevaluating aggregates and paving mixtures so that predictions can be made covering skid resistance properties of proposed and in service pavement types are discussed. A correlation was established between the field testing using the data from the British Portable Tester and the Locked Wheel Pavement Friction Trailer at speeds of 40 and 55 mph. Core samples were extracted from the Locked Wheel Tester Skid Path and subjected to wear on the small wheel circular track with periodic surface friction testing. The final step was to remix and remold the cored pavement samples or make samples with new materials to obtain an 'as new' surface and again subject these samples to wear on the small wheel circular track with periodic testing.

  5. RAPID INSPECTION OF PAVEMENT MARKINGS USING MOBILE LIDAR POINT CLOUDS

    Directory of Open Access Journals (Sweden)

    H. Zhang

    2016-06-01

    Full Text Available This study aims at building a robust semi-automated pavement marking extraction workflow based on the use of mobile LiDAR point clouds. The proposed workflow consists of three components: preprocessing, extraction, and classification. In preprocessing, the mobile LiDAR point clouds are converted into the radiometrically corrected intensity imagery of the road surface. Then the pavement markings are automatically extracted with the intensity using a set of algorithms, including Otsu’s thresholding, neighbor-counting filtering, and region growing. Finally, the extracted pavement markings are classified with the geometric parameters using a manually defined decision tree. Case studies are conducted using the mobile LiDAR dataset acquired in Xiamen (Fujian, China with different road environments by the RIEGL VMX-450 system. The results demonstrated that the proposed workflow and our software tool can achieve 93% in completeness, 95% in correctness, and 94% in F-score when using Xiamen dataset.

  6. Low cost pavement marking materials based on plasticized sulfur

    Science.gov (United States)

    Dale, J. M.

    1982-04-01

    Pavement marking was made more cost effective by reducing the cost of the marking materials. A low cost marking material based on sulfur was developed. Elemental sulfur is a hard, brittle, crystalline material which, on heating, melts to a thin liquid that can be spray applied. If molten elemental sulfur is spray applied to the road as markings, it will on application solidify, crack and adhere poorly to the road. The first ten high speed trucks that ride over the markings will remove them. To make a useful sulfur based pavement marking material it was necessary to chemically modify (plasticize) the sulfur and mix it with fillers and pigments such that it had all of the characteristics desired of a pavement marking material. Yellow and white formulations were developed. For identification they were given the names YS-EIGHT and WS-EIGHT for the yellow and white formulations.

  7. Rapid Inspection of Pavement Markings Using Mobile LIDAR Point Clouds

    Science.gov (United States)

    Zhang, Haocheng; Li, Jonathan; Cheng, Ming; Wang, Cheng

    2016-06-01

    This study aims at building a robust semi-automated pavement marking extraction workflow based on the use of mobile LiDAR point clouds. The proposed workflow consists of three components: preprocessing, extraction, and classification. In preprocessing, the mobile LiDAR point clouds are converted into the radiometrically corrected intensity imagery of the road surface. Then the pavement markings are automatically extracted with the intensity using a set of algorithms, including Otsu's thresholding, neighbor-counting filtering, and region growing. Finally, the extracted pavement markings are classified with the geometric parameters using a manually defined decision tree. Case studies are conducted using the mobile LiDAR dataset acquired in Xiamen (Fujian, China) with different road environments by the RIEGL VMX-450 system. The results demonstrated that the proposed workflow and our software tool can achieve 93% in completeness, 95% in correctness, and 94% in F-score when using Xiamen dataset.

  8. 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)

  9. 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

  10. Cold Region Pavements%寒区路面

    Institute of Scientific and Technical Information of China (English)

    GuyDore

    2002-01-01

    The article mainly discusses several essential problems of cold region pavement, including thermal cracking of asphalt concrete, cracking deterioration and heaving, frost heave, seasonal and long term roughness induced by different frost heave, frost heave cracking, bearing capacity loss during spring thaw. The reason for these problems is that cold region pavements are subjected to intense solicitation by climatic and environmental factors. The author offers several models corresponding to the solicitation. Furthermore in conclusion of the article the author indicates future research for cold region.

  11. Thin, applied surfacing for improving skid resistance of concrete pavements

    Science.gov (United States)

    Scholer, C. F.

    1980-12-01

    The use of select aggregate in a thin wearing surface of portland cement mortar to prolone or restore a concrete pavement's ability to develop high friction was accomplished. Two fine aggregates, blast furnace slag and lightweight expanded shale were found to exhibit skid resistance greater than the other aggregates evaluated. The British polishing wheel was used in the laboratory evaluation of aggregate to simulate wear. The need for a method of restoring friction to a worn, but otherwise sound concrete pavement led to a field evaluation of several different techniques for placing a very thin overlay. The successful method was a broomed, very thin layer of mortar, 3 mm thick.

  12. Deterioration modeling for condition assessment of flexible pavements considering extreme weather events

    Science.gov (United States)

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

    2015-04-01

    Accurate pavement management systems are essential for states' Department Of Transportation and roadway agencies to plan for cost-effective maintenance and repair (M and R) strategies. Pavement deterioration model is an imperative component of any pavement management system since the future budget and M and R plans would be developed based on the predicted pavement performance measures. It is crucial for the pavement deterioration models to consider the factors that significantly aggravate the pavement condition. While many studies have highlighted the impact of different environmental, load, and pavement's structure on the life cycle of the pavement, effect of extreme weather events such as Floods and Snow Storms have often been overlooked. In this study, a pavement deterioration model is proposed which would consider the effect of traffic loads, climate conditions, and extreme weather events. Climate, load and performance data has been compiled for over twenty years and for eight states using the Long Term Pavement Performance (LTPP) and National Oceanic and Atmospheric Administration (NOAA) databases. A stepwise regression approach is undertaken to quantify the effect of the extreme weather events, along with other influential factors on pavement performance in terms of International Roughness Index (IRI). Final results rendered more than 90% correlation with the quantified impact values of extreme weather events.

  13. Tactile pavement for guiding walking direction: An assessment of heading direction and gait stability.

    Science.gov (United States)

    Pluijter, Nanda; de Wit, Lieke P W; Bruijn, Sjoerd M; Plaisier, Myrthe A

    2015-10-01

    For maintaining heading direction while walking we heavily rely on vision. Therefore, walking in the absence of vision or with visual attention directed elsewhere potentially leads to dangerous situations. Here we investigated whether tactile information from the feet can be used as a (partial) substitute for vision in maintaining a stable heading direction. If so, participants should be better able to keep a constant heading direction on tactile pavement that indicates directionality than on regular flat pavement. However, such a pavement may also be destabilizing. Thus we asked participants to walk straight ahead on regular pavement, and on tactile pavement (tiles with ridges along the walking direction) while varying the amount of vision. We assessed the effects of the type of pavement as well as the amount of vision on the variability of the heading direction as well as gait stability. Both of these measures were calculated from accelerations and angular velocities recorded from a smartphone attached to the participants trunk. Results showed that on tactile pavement participants had a less variations in their heading direction than on regular pavement. The drawback, however, was that the tactile pavement used in this study decreased gait stability. In sum, tactile pavement can be used as a partial substitute for vision in maintaining heading direction, but it can also decrease gait stability. Future work should focus on designing tactile pavement that does provided directional clues, but is less destabilizing. PMID:26344427

  14. 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.

  15. 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

  16. Calibrating mechanistic-empirical pavement performance models with an expert matrix

    Energy Technology Data Exchange (ETDEWEB)

    Tighe, S.; AlAssar, R.; Haas, R. [Waterloo Univ., ON (Canada). Dept. of Civil Engineering; Zhiwei, H. [Stantec Consulting Ltd., Cambridge, ON (Canada)

    2001-07-01

    Proper management of pavement infrastructure requires pavement performance modelling. For the past 20 years, the Ontario Ministry of Transportation has used the Ontario Pavement Analysis of Costs (OPAC) system for pavement design. Pavement needs, however, have changed substantially during that time. To address this need, a new research contract is underway to enhance the model and verify the predictions, particularly at extreme points such as low and high traffic volume pavement design. This initiative included a complete evaluation of the existing OPAC pavement design method, the construction of a new set of pavement performance prediction models, and the development of the flexible pavement design procedure that incorporates reliability analysis. The design was also expanded to include rigid pavement designs and modification of the existing life cycle cost analysis procedure which includes both the agency cost and road user cost. Performance prediction and life-cycle costs were developed based on several factors, including material properties, traffic loads and climate. Construction and maintenance schedules were also considered. The methodology for the calibration and validation of a mechanistic-empirical flexible pavement performance model was described. Mechanistic-empirical design methods combine theory based design such as calculated stresses, strains or deflections with empirical methods, where a measured response is associated with thickness and pavement performance. Elastic layer analysis was used to determine pavement response to determine the most effective design using cumulative Equivalent Single Axle Loads (ESALs), below grade type and layer thickness.The new mechanistic-empirical model separates the environment and traffic effects on performance. This makes it possible to quantify regional differences between Southern and Northern Ontario. In addition, roughness can be calculated in terms of the International Roughness Index or Riding comfort Index

  17. Immediate bleeding complications in dental implants: A systematic review

    OpenAIRE

    Balaguer Martí, José Carlos; Peñarrocha Oltra, David; Balaguer Martínez, José; Peñarrocha Diago, Miguel

    2014-01-01

    Objective: A review is made of the immediate or immediate postoperative bleeding complications in dental implants, with a view to identifying the areas of greatest bleeding risk, the causes of bleeding, the length of the implants associated with bleeding, the most frequently implicated blood vessels, and the treatments used to resolve these complications. Material and Methods: A Medline (PubMed) and Embase search was made of articles on immediate bleeding complications in dental implants publ...

  18. Performance Evaluation of Flexible Pavements: A Case Study

    Directory of Open Access Journals (Sweden)

    V.K Chakravarthi1 ,

    2015-10-01

    Full Text Available : Flexible pavements get distress during their service life because of increase in traffic particularly commercial vehicles. The present study focuses on finding the increase of magnitude of deformations from 2008 to 2015 traffic data using ANSYS for which the BRTS stretch in Visakhapatnam is considering five locations along the stretch.

  19. Ground Penetrating Radar Assessment of Flexible Road Pavement Degradation

    Directory of Open Access Journals (Sweden)

    Sandro Colagrande

    2011-01-01

    Full Text Available GPR investigations were used to study degraded road pavements built in cutting sections. Road integrity was assessed via quantitative analysis of power curves. 1600 MHz and 600 MHz radar sections were collected in 40 damaged and undamaged road pavement sites. The collected data were processed as follows: (i linearisation with regression analysis of power curves; (ii assessment of absorption angle α′ which is directly proportional to absorption coefficient α (this was obtained by setting the e.m. propagation velocity to 10 cm/ns; (iii comparison of absorption coefficients in both damaged and undamaged zones with respect to road pavement degradation. If the absorption coefficients of damaged and undamaged road sections have nearly the same value, then the likely cause of degradation is the fatigue or the thermal shrinkage; if they are not, then road degradation is due to the different compactness of the soil caused by vehicular traffic load. In a considerable number of sites, the statistical comparison of damaged and undamaged zones through the absorption coefficient analysis shows that surface observations of road pavements are quite consistent with power curve analyses.

  20. 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.

  1. Optimisation of the Crack Pattern in Continuously Reinforced Concrete Pavements

    NARCIS (Netherlands)

    Ren, D.

    2015-01-01

    Recent field investigations on several new Continuously Reinforced Concrete Pavements (CRCP) in Belgium indicate that its crack pattern is characterized by low mean crack spacing along with a high percentage of clusters of closely spaced cracks. Field surveys also indicate that it is difficult to si

  2. Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash

    Directory of Open Access Journals (Sweden)

    Isamu Yoshitake

    2015-08-01

    Full Text Available Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

  3. 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...

  4. Revised procedure for pavement design under seasonal frost conditions

    Science.gov (United States)

    Berg, R. L.; Johnson, T. C.

    1983-09-01

    This report presents engineering guidance and design criteria for pavements at Army and Air Force facilities in seasonal frost areas. Design methods for controlling surface roughness and loss of subgrade strength during thawing periods are provided. Criteria for using thermal insulating materials and membrane encapsulated soil layers in seasonal frost areas are presented. Six design examples are included.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1999-07-01

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

  6. Prediction of subgrade moisture conditions for purposes of pavement design

    OpenAIRE

    Correia, A. Gomes

    1996-01-01

    The purpose of this paper is to summarize the procedures for determining moisture conditions in subgrade soils and make recommendations regarding the practical applications to pavement design. By using data from different moisture studies some moisture models were tested to demonstrate their capability of predicting ultimate moisture contents.

  7. Representative volume element of asphalt pavement for electromagnetic measurements

    Directory of Open Access Journals (Sweden)

    Terhi Pellinen

    2015-02-01

    Full Text Available The motivation for this study was to investigate the representative volume element (RVE needed to correlate the nondestructive electromagnetic (EM measurements with the conventional destructive asphalt pavement quality control measurements. A large pavement rehabilitation contract was used as the test site for the experiment. Pavement cores were drilled from the same locations where the stationary and continuous Ground Penetrating Radar (GPR measurements were obtained. Laboratory measurements included testing the bulk density of cores using two methods, the surface-saturated dry method and determining bulk density by dimensions. Also, Vector Network Analyzer (VNA and the through specimen transmission configuration were employed at microwave frequencies to measure the reference dielectric constant of cores using two different footprint areas and therefore volume elements. The RVE for EM measurements turns out to be frequency dependent; therefore in addition to being dependent on asphalt mixture type and method of obtaining bulk density, it is dependent on the resolution of the EM method used. Then, although the average bulk property results agreed with theoretical formulations of higher core air void content giving a lower dielectric constant, for the individual cores there was no correlation for the VNA measurements because the volume element seizes deviated. Similarly, GPR technique was unable to capture the spatial variation of pavement air voids measured from the 150-mm drill cores. More research is needed to determine the usable RVE for asphalt.

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

    DEFF Research Database (Denmark)

    Bendixen, Søren; Stang, Henrik

    1996-01-01

    -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...

  9. Monitoring Strategies in Permeable Pavement Systems to Optimize Maintenance Scheduling

    Science.gov (United States)

    As the surface in a permeable pavement system clogs and performance decreases, maintenance is required to preserve the design function. Currently, guidance is limited for scheduling maintenance on an as needed basis. Previous research has shown that surface clogging in a permea...

  10. An Approach for Nonlinear Fatigue Damage Evaluation in Asphalt Pavements

    Science.gov (United States)

    Rajbongshi, Pabitra; Thongram, Sonika

    2016-08-01

    Fatigue due to vehicular loads is one of the primary distress mechanisms in asphalt pavements. It happens primarily due to deterioration in asphalt material with load repetitions. Degradation of asphalt material may be evaluated using different parameters. In view of degradation, the incremental damage in a given pavement section would be different for different repetitions, even with same loadings. Therefore, the damage progression becomes nonlinear with repetitions. Accounting such nonlinearity in damage accumulation, and based on different damage evaluation parameters, this paper presents an equivalent approach for fatigue damage evaluation in asphalt pavements. Traditional fatigue equation adopted in mechanistic-empirical pavement design has been used in the present work. Four different criteria, namely number of load repetitions, asphalt stiffness reduction, strain enhancement and fatigue life reduction with repetitions are considered for damage estimation. The proposed approach could estimate same value of nonlinear damage, irrespective of the criteria used. The simplest form of criterion i.e. the number of load repetitions can be used for fatigue performance evaluation. Probabilistically, the damage propagation is also correlated and assessed with the failure probability.

  11. 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...

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

    OpenAIRE

    Simonas Tamaliūnas; Henrikas Sivilevičius

    2011-01-01

    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

  13. Accuracy of rockall score for in hospital re bleeding among cirrhotic patients with variceal bleed

    International Nuclear Information System (INIS)

    To assess the diagnostic accuracy of Roc kall scoring system for predicting in-hospital re-ble- eding in cirrhotic patients presenting with variceal bleed. Material and Methods: This descriptive case series study was conducted at Department of Medicine Combined Military Hospital Lahore from December 2013 to May 2014. We included patients with liver cirrhosis who presented with upper GI bleeding and showed varices as the cause of bleeding on endoscopy. Clinical and endoscopic features were noted to calculate Rockall score. Patients with score < 2 and > 8 were included. After treating with appropriate pharmacological and endoscopic therapy, patients were followed for re-bleeding for 10 days. Diagnostic accuracy was assessed by calculating sensitivity, specificity, positive and negative predictive values using 2 x 2 tables. Results: In the study, 175 patients were included. Mean age was 51.5 ± 1.22 years. Male to female ratio was 1.5 to 1.0 out of 175 patients, 157 patients (89.7%) were of low risk group (score = 2) while 18 patients (10.3%) were in high risk group (score > 8). In low risk group, re-bleeding occurred only in 2 patients (1.2%) while in high risk group, re-bleeding occurred in 14 patients (78%). Rockall score was found to have good diagnostic accuracy with sensitivity of 87.5%, specificity of 97.48%, positive predictive value of 77.8% and negative predictive value of 98.7%. Conclusion: In cases of variceal bleed, frequency of re-bleed is less in patients who are in low risk category with lower Rockall score and high in high risk patients with higher rockall score. The Rockall score has a good diagnostic accuracy in prediction of re-bleed in variceal bleeding. (author)

  14. Radionuclide detection of lower gastrointestinal bleeding sites

    International Nuclear Information System (INIS)

    A retrospective review of two years' experience with radionuclide screening to detect lower gastrointestinal bleeding sites was conducted at New York's Montefiore Medical Center. Of 82 studies performed in 63 patients, 13 identified active bleeding sites. Only three of eight angiograms obtained in these 13 patients were positive. Thirteen contrast angiograms were performed in the group of 50 patients with negative radionuclide studies of which ten were negative and one was equivocal. The results of this study suggest that the Tc-99m sulfur colloid study for active lower gastrointestinal (GI) bleeding is an effective screening procedure. Positive studies help determine which vessel to catheterize selectively if an angiogram is to be performed. If vascular ectasis is still suspected following a negative radionuclide study, contrast angiography can be more efficaciously performed on a nonemergent basis

  15. Laparoscopic resection of bleeding gastric polyps.

    Science.gov (United States)

    Siu, W T; Leong, H T; Li, M K

    1997-03-01

    Gastric polyps account for a small proportion of gastric neoplasms. Many of them presented with acute or chronic bleeding. Endoscopic polypectomy is the preferred treatment modality. However, endoscopic polypectomy is often incomplete and impossible for large polyps. Large and intramural polyps require laparotomy and excision. From June to October 1995, four patients with bleeding gastric polyps received laparoscopic resection in our unit. All were women, aged 40-78, with polyps 2-6 cm in diameter. One patient underwent emergency surgery for active bleeding. The others received elective operations. Operating time ranged from 90 to 120 min. There was no perioperative morbidity or mortality. Full diet was resumed by the 4th postoperative day. The average postoperative hospital stay was 5. 3 days (4-7). Laparoscopic resection of gastric polyp is a preferable treatment option when endoscopic treatment fails.

  16. Somatostatin analogues for acute bleeding oesophageal varices

    DEFF Research Database (Denmark)

    Gøtzsche, Peter C.; Hrobjartsson, A.

    2008-01-01

    BACKGROUND: Somatostatin and its derivatives are sometimes used for emergency treatment of bleeding oesophageal varices in patients with cirrhosis of the liver. OBJECTIVES: To study whether somatostatin or its analogues improve survival or reduce the need for blood transfusions in patients...... with bleeding oesophageal varices. SEARCH STRATEGY: PubMed and The Cochrane Library were searched (November 2007). Reference lists of publications, contacts with authors. SELECTION CRITERIA: All randomised trials comparing somatostatin or analogues with placebo or no treatment in patients suspected of acute...... or recent bleeding from oesophageal varices. DATA COLLECTION AND ANALYSIS: The outcome measures extracted were: mortality, blood transfusions, use of balloon tamponade, initial haemostasis and rebleeding. Intention-to-treat analyses including all randomised patients were conducted if possible; a random...

  17. NonPAS: A Program for Nonlinear Analysis of Flexible Pavements

    Directory of Open Access Journals (Sweden)

    Ali Reza Ghanizadeh

    2015-06-01

    Full Text Available The primary step in design of a pavement using Mechanistic-Empirical (M-E method is the analysis of pavement and calculation of the critical responses of pavement under various loadings. This confirms the need for developing pavement analysis software as an analytical base of the M-E method. To this end, NonPAS program has been developed for linear and nonlinear analysis of flexible pavements. Developed program allows nonlinear analysis of flexible pavements using five nonlinear models, including K-θ, Uzan, Uzan-Witczak, MEPDG 2002 and Bilinear models. Nonlinear Analysis of flexible pavements by utilizing these constitutive models provides a more accurate modeling of granular material behavior. Developed program can be used to analyze a pavement system consists of maximum of 10 layers, which is subjected to a maximum of six circular loads. Developed program allows for calculating the responses at 400 different points of pavement. In order to validate the results of linear and nonlinear analysis, responses obtained from NonPAS have been compared with responses obtained using Kenlayer program. Results show very good agreement between responses, which are obtained using both linear and nonlinear analysis and approve that developed program can be used with high reliability for the purposes of pavement analysis and design.

  18. An assessment of the skid resistance effect on traffic safety under wet-pavement conditions.

    Science.gov (United States)

    Pardillo Mayora, José M; Jurado Piña, Rafael

    2009-07-01

    Pavement-tire friction provides the grip that is required for maintaining vehicle control and for stopping in emergency situations. Statistically significant negative correlations of skid resistance values and wet-pavement accident rates have been found in previous research. Skid resistance measured with SCRIM and crash data from over 1750km of two-lane rural roads in the Spanish National Road System were analyzed to determine the influence of pavement conditions on safety and to assess the effects of improving pavement friction on safety. Both wet- and dry-pavement crash rates presented a decreasing trend as skid resistance values increased. Thresholds in SCRIM coefficient values associated with significant decreases in wet-pavement crash rates were determined. Pavement friction improvement schemes were found to yield significant reductions in wet-pavement crash rates averaging 68%. The results confirm the importance of maintaining adequate levels of pavement friction to safeguard traffic safety as well as the potential of pavement friction improvement schemes to achieve significant crash reductions. PMID:19540980

  19. Effect Analysis of Vehicle System Parameters on Dynamic Response of Pavement

    Directory of Open Access Journals (Sweden)

    Rong-xia Xia

    2015-01-01

    Full Text Available In order to study the damage of a semirigid pavement under vehicle loads with varied parameters, the random dynamic loads applied on the pavement by a running vehicle were computed with two degrees of freedom, quarter-vehicle model, and then a three-dimensional finite element analysis model of semirigid asphalt pavement was established. With the peak stress index of each pavement layer, the effect of varied vehicle parameters on pavement response was studied. The results indicated that the stress wave frequency of each pavement layer was similar to that of the dynamic random load, and, with increased pavement depth, the wave effect decreased. The pavement response increased with increased suspension stiffness and tire stiffness and decreased with increased suspension damping and tire damping. Furthermore, compared to the stiffness, the response variation induced by the damping was orders of magnitude lower. Compared with the traditional time response analysis method, the peak response analysis of the pavement structure was more scientific, rational, and intuitive, which could be useful for the study of vehicle-pavement interaction and road damage.

  20. The Approach to Occult Gastrointestinal Bleed.

    Science.gov (United States)

    Naut, Edgar R

    2016-09-01

    Occult gastrointestinal bleeding is not visible and may present with a positive fecal occult blood test or iron deficiency anemia. Obscure bleeding can be overt or occult, with no source identified despite an appropriate diagnostic workup. A stepwise approach to this evaluation after negative upper and lower endoscopy has been shown to be cost effective. This includes repeat endoscopies if warranted, followed by video capsule endoscopy (VCE) if no obstruction is present. If the VCE is positive then specific endoscopic intervention may be possible. If negative, patients may undergo either repeat testing or watchful waiting with iron supplements.

  1. [Jejunal GIST with obscure gastrointestinal bleeding].

    Science.gov (United States)

    Nelly Manrique, María; Frisancho, Oscar; Rivas Wong, Luz; Palomino, Américo

    2011-01-01

    We report the case of a woman of 84 years with a history of cardiac arrhythmia and hemorrhoids. She had multiple hospitalizations and transfusions for symptomatic iron deficiency anemia, endoscopic studies showed only small diverticula and colon polyps. He was later hospitalized with bloody stools red wines, upper endoscopy and colonoscopy showed gastritis, small colonic ulcers, colonic polyp and multiple diverticula. Readmitted with bleeding of obscure origin, on that occasion showed gastritis, antral erosions, small ulcers, colon polyps and colon ulcers in the process of healing, capsule endoscopy showed angiodysplasia in jejunum, anterograde enteroscopy detected some erythematous lesions in proximal jejunum without evidence of bleeding. Again hospitalized for melena and abdominal. PMID:22086325

  2. [Epidemiology of upper gastrointestinal bleeding in Gabon].

    Science.gov (United States)

    Gaudong Mbethe, G L; Mounguengui, D; Ondounda, M; Magne, C; Bignoumbra, R; Ntsoumou, S; Moussavou Kombila, J-B; Nzenze, J R

    2014-01-01

    The department of internal medicine of the military hospital of Gabon managed 92 cases of upper gastrointestinal bleeding from April 2009 to November 2011. The frequency of these hemorrhages in the department was 8.2%; they occurred most often in adults aged 30-40 years and 50-60 years, and mainly men (74%). Erosive-ulcerative lesions (65.2%) were the leading causes of hemorrhage, followed by esophageal varices (15.2%). These results underline the importance of preventive measures for the control of this bleeding.

  3. Diagnosis of gastrointestinal bleeding: A practical guide for clinicians

    Institute of Scientific and Technical Information of China (English)

    Bong; Sik; Matthew; Kim; Bob; T; Li; Alexander; Engel; Jaswinder; S; Samra; Stephen; Clarke; Ian; D; Norton; Angela; E; Li

    2014-01-01

    Gastrointestinal bleeding is a common problem encountered in the emergency department and in the primary care setting. Acute or overt gastrointestinal bleeding is visible in the form of hematemesis, melena or hematochezia. Chronic or occult gastrointestinal bleeding is notapparent to the patient and usually presents as positive fecal occult blood or iron deficiency anemia. Obscure gastrointestinal bleeding is recurrent bleeding when the source remains unidentified after upper endoscopy and colonoscopic evaluation and is usually from the small intestine. Accurate clinical diagnosis is crucial and guides definitive investigations and interventions. This review summarizes the overall diagnostic approach to gastrointestinal bleeding and provides a practical guide for clinicians.

  4. [OMEPRAZOL VS RANITIDINE IN UPPER DIGESTIVE BLEEDING

    Science.gov (United States)

    Regis R, Regina; Bisso A, Aland; Rebaza, Segundo

    1999-01-01

    Pectic ulcer is the most frequent cause of gastrointestinal bleeding. The homeostatic mechanism of bleeding, and coagulation, does not happen with values of pH less than 5,0. Therefore neutralization of gastric acidity (pH more than 5,0) is a recourse of control, improve the evolution and healing of peptic ulcer and to avoid a new bleeding. The aim of this study was to compare the results of treatment with omeprazole and ranitidine, in 57 patients admitted at emergency room of the Hospital Central de la Polic a Nacional del Per with endoscopic diagnosis of peptic ulcer, using Forrest classification. Patients received omeprazole 40 mg in bolus IV, followed by continuos infusion of 8 mg/hour for 72 hours (group A) or ranitidine 50 mg IV each 8 hours for 72 hours (group B). A new endoscopy was made 72 hours after admission demostrated a succesful therapy in both group. Bleeding stopped in 26/27 patients in group A (96,2%) and in 23/30 patients in group B (76,6%) (pomeprazole IV is more effective than ranitidine IV in the control of UGB because of peptic ulcer and provides a faster healing. PMID:12181579

  5. Decision of National and Provincial Highway Asphalt Pavement Structure Based on Value Engineering

    Directory of Open Access Journals (Sweden)

    Yingwei Ren

    2014-01-01

    Full Text Available It is important that decision of asphalt pavement structure requires overall considerations of the performance and financial investment. To have asphalt pavement structure fulfilling good reliability, the asphalt pavement structure decision was researched based on value engineering theory. According to the national and provincial highway investigation data in Shandong Province during the last decade, the asphalt pavement performance attenuation rules of traffic levels and asphalt layer thicknesses were developed, and then the road performance evaluation method was presented. In addition, the initial investments, the costs of road maintenance, and middle-scale repair in a period were analyzed. For the light traffic and medium traffic example, using the value engineering method, the pavement performance and costs of which thickness varies from 6 cm to 10 cm were calculated and compared. It was concluded that value engineering was an effective method in deciding the asphalt pavement structure.

  6. Endovascular Management of Acute Bleeding Arterioenteric Fistulas

    International Nuclear Information System (INIS)

    The objective of this study was to review the outcome of endovascular transcatheter repair of emergent arterioenteric fistulas. Cases of abdominal arterioenteric fistulas (defined as a fistula between a major artery and the small intestine or colon, thus not the esophagus or stomach), diagnosed over the 3-year period between December 2002 and December 2005 at our institution, were retrospectively reviewed. Five patients with severe enteric bleeding underwent angiography and endovascular repair. Four presented primary arterioenteric fistulas, and one presented a secondary aortoenteric fistula. All had massive persistent bleeding with hypotension despite volume substitution and transfusion by the time of endovascular management. Outcome after treatment of these patients was investigated for major procedure-related complications, recurrence, reintervention, morbidity, and mortality. Mean follow-up time was 3 months (range, 1-6 months). All massive bleeding was controlled by occlusive balloon catheters. Four fistulas were successfully sealed with stent-grafts, resulting in a technical success rate of 80%. One patient was circulatory stabilized by endovascular management but needed immediate further open surgery. There were no procedure-related major complications. Mean hospital stay after the initial endovascular intervention was 19 days. Rebleeding occurred in four patients (80%) after a free interval of 2 weeks or longer. During the follow-up period three patients needed reintervention. The in-hospital mortality was 20% and the 30-day mortality was 40%. The midterm outcome was poor, due to comorbidities or rebleeding, with a mortality of 80% within 6 months. In conclusion, endovascular repair is an efficient and safe method to stabilize patients with life-threatening bleeding arterioenteric fistulas in the emergent episode. However, in this group of patients with severe comorbidities, the risk of rebleeding is high and further intervention must be considered

  7. COMPUTATIONAL INVESTIGATION OF COMPOSED MULTILAYERED HALF-SPACE STRENGTH UNDER PAVEMENT

    Directory of Open Access Journals (Sweden)

    Svetlana Talakh

    2015-10-01

    Full Text Available The article presents mathematical model of non-linear subgrade half-space on the basis of the von Mises advanced yieldcriterion. We have performed computational investigations of non-rigid pavement deflected mode in plane problem statement under simulation of subgrade half-space active zone including the layers of pavement. The results receiveds how the plastoelastic deformation development influences the strength of non-rigid pavement.

  8. Asphalt Materials Characterization in Support of Implementation of the Proposed Mechanistic-Empirical Pavement Design Guide

    OpenAIRE

    Flintsch, Gerardo W.; Loulizi, Amara; Stacey D. Diefenderfer; Khaled A. Galal; Diefenderfer, Brian K.

    2007-01-01

    The proposed Mechanistic-Empirical Pavement Design Guide (MEPDG) procedure is an improved methodology for pavement design and evaluation of paving materials. Since this new procedure depends heavily on the characterization of the fundamental engineering properties of paving materials, a thorough material characterization of mixes used in Virginia is needed to use the MEPDG to design new and rehabilitated flexible pavements. The primary objective of this project was to perform a full hot-mix a...

  9. 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...

  10. Correlation of bleeding pattern with endometrial histopathologic results in perimenopausal women with abnormal uterine bleeding

    Directory of Open Access Journals (Sweden)

    Zehra Yilmaz

    2015-06-01

    Full Text Available Background: Abnormal Uterine Bleeding (AUB is referred as bleeding outside of normal menstruation pattern and it is the most common gynecological problem for women of all ages. This study was evaluated the correlation of menstrual bleeding patterns and endometrial histopathological findings in perimenopausal women. Methods: This study was done on perimenopausal aged women presented with AUB for the last 6 months at a gynecology clinic of a tertiary medical center. Only the patients with isolated endometrial causes of AUB were selected for study. A total of 313 cases were included in the study. Abnormal bleeding patterns of the patients were recorded and endometrial sampling was performed to all women. AUB was classified as menorrhagia, metrorrhagia, menometrorrhagia, polymenorrhea, intermenstrual bleeding, and histopathological findings were classified as Proliferative Endometrium (PE, Secretory Endometrium (SE, Disordered Proliferative Pattern (DPP, Endometrial Polyp (EP, Chronic Endometritis (CE, Endometrial Hyperplasia (EH, and Endometrial Adenocarcinoma (CA. Results: The most common bleeding pattern was menorrhagia (45.0% and the most common histopathological finding was PE+SE (52.0% in our study. PE+SE and endometrial hyperplasia without atypia were found more common in menorrhagia group. The most histopathological findings were found PE+SE in menometrorrhagia and polymenorrhea group (P 0.05. Conclusions: We concluded that although menometrorrhagia and polymenorrhea were significantly more associated with PE+SE, intermenstrual bleeding was significantly more associated with EP and CE. It is noteworthy that endometrial hyperplasia without atypia is significantly higher in patients with menorrhagia which is the most common abnormal bleeding pattern in perimenopausal aged women. [Int J Reprod Contracept Obstet Gynecol 2015; 4(3.000: 547-550

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

    OpenAIRE

    Kundan Meshram; H.S. Goliya; Akhilesh Poddar

    2013-01-01

    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 ca...

  12. Practical research on the modified rubber powder asphalt pavement engineering%橡胶粉改性沥青路面工程实践研究

    Institute of Scientific and Technical Information of China (English)

    孟建建; 勾煜

    2012-01-01

    Through comprehensively considering features and influential factors of rubber powder asphalt, the paper describes the production and construction technology of the new rubber power modified asphalt pavement from aspects of raw material selection of rubber powder, basic asphalt, coarse aggregate, fine aggregate and filling materials, the design and production, transportation, paving and rolling and forming of rubber powder asphalt mixture. Practice proves that rubber powder asphalt pavement has great effect of bleeding and sliding resistance and noise resistance. Through nearly two years' operation and return visit, it turns out that the pavement eveness is good without potholes. In addition, the proprietors are satisfied with the highway conditions.%综合考虑橡胶粉沥青的特点及其影响因素,从橡胶粉、基质沥青、粗集料、细集料和填料等原材料的选用,橡胶粉沥青混合料的设计与生产、运输、摊铺以及碾压成型等角度,详细阐述了一种新型的橡胶粉改性沥青路面的生产与施工工艺,实践证明:橡胶粉沥青路面具有良好的泌水性和抗滑、防噪效果,经过近两年的运行和回访表明,路面平整度等状况良好,无车辙、无坑洞,业主反映较好。

  13. Investigations of the dynamics of road pavement reflectance

    Institute of Scientific and Technical Information of China (English)

    Kang Jiang; Kai Yu; Yongchao Zhao

    2012-01-01

    Road pavement reflectance is usually assumed to be invariant in short periods of time in some quantitative remote sensing applications. To examine its variability,reflectance sequences of concrete and asphalt pavement are measured in field for half a day in visible and near-infarecd (VNIR) spectral range using dual-beam method.As much as 20.7% and 3.52% of relative changes are found in asphalt and concrete reflectance data at 550 nm,and all VNIR bands demonstrate similar variations found to correlate with both illumination geometry and the relative portion of diffuse irradiance.In this letter,this effect is interpreted from a mathematic view.Further studies are needed to model the dynamics of reflectance physically.

  14. Mechanical Properties of Asphalt Pavement Structure in Highway Tunnel

    Institute of Scientific and Technical Information of China (English)

    SHI Chun-xiang; GUO Zhong-yin

    2008-01-01

    A linear full 3D finite element method (FEM) was performed in order to present the key design parameters of highway tunnel asphalt pavement under double-wheel load on rectangular loaded area considering horizontal contact stress induced by the acceleration/deceleration of vehicles. The key design parameters are the maximum horizontal tensile stresses at the surface of the asphalt layer, the maximum horizontal tensile stresses at the bottom of the asphalt layer and the maximum vertical shear stresses at the surface of the as- phalt layer were calculated. The influencing factors such as double-wheel weight; asphalt layer thickness; base course stiffness modulus and thickness; and the contact conditions among the structure layers on these key design parameters were also examined separately to propose construction procedures of highway tunnel asphalt pavement.

  15. Automatic Road Pavement Assessment with Image Processing: Review and Comparison

    Directory of Open Access Journals (Sweden)

    Sylvie Chambon

    2011-01-01

    Full Text Available In the field of noninvasive sensing techniques for civil infrastructures monitoring, this paper addresses the problem of crack detection, in the surface of the French national roads, by automatic analysis of optical images. The first contribution is a state of the art of the image-processing tools applied to civil engineering. The second contribution is about fine-defect detection in pavement surface. The approach is based on a multi-scale extraction and a Markovian segmentation. Third, an evaluation and comparison protocol which has been designed for evaluating this difficult task—the road pavement crack detection—is introduced. Finally, the proposed method is validated, analysed, and compared to a detection approach based on morphological tools.

  16. Use of Recycled Aggregate and Fly Ash in Concrete Pavement

    Directory of Open Access Journals (Sweden)

    Myle N. James

    2011-01-01

    Full Text Available Problem statement: Recycled materials aggregate from the demolished concrete structures and fly ash from burning coal shows the possible application as structural and non structural components in concrete structures. This research aims to evaluate the feasibility of using concrete containing recycled concrete aggregate and fly ash in concrete pavement. Approach: Two water cement ratio (0.45 and 0.55 the compressive strength, modulus of electricity and flexural strength for concrete with recycled aggregate and fly ash with 0, 25% replacing cement in mass were considered. Results: The material properties of recycled aggregate concrete with fly ash indicate comparable results with that of concrete with natural aggregate and without fly ash. Conclusion/Recommendations: The recycled materials could be used in concrete pavement and it will promote the sustainability of concrete.

  17. Vivax malaria:a rare cause of thalamic bleed

    Institute of Scientific and Technical Information of China (English)

    Jaydeep Sarkar; Biku Naik; Atul Gawande; Atul Goel

    2012-01-01

    Most common cause of thalamic bleed is hypertension; other causes are arteriovenous malformation, aneurysm, bleeding diathesis, drugs, amyloid angiopathy, tumor etc.We present a case ofPlasmodium vivax (P. vivax) malaria with unusual site of bleeding i.e. left thalamus of brain.To the best of our knowledge, this is the first reported case of thalamic bleed caused by vivax malaria in absence of severe thrombocytopenia/disseminated intravascular coagulation (DIC).

  18. Bleeding from the pancreas - a comparison of imaging methods

    Energy Technology Data Exchange (ETDEWEB)

    Roedl, W.; Nebel, G.; Englehard, K.

    1984-05-01

    Four patients with spontaneous bleeding from the pancreas are described. Transpapillary bleeding is diagnosed endoscopically. Angiography can demonstrate the eroded vessel directly. Ultrasound, CT and ERCP demonstrate the underlying abnormality in the pancreas. Bleeding into a cyst produces characteristic echoes, or an increase in density. NMR is able to demonstrate pancreatitis and pancreatic pseudo-cysts. Early diagnosis is extremely important, since without appropriate surgery, pancreatic bleeding is frequently fatal. 7 figs.

  19. Capsule endoscopy: Current status in obscure gastrointestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    R Gupta; Nageshwar Duvvuru Reddy

    2007-01-01

    Capsule endoscopy (CE) is a safe, non invasive diagnostic modality for the evaluation of small bowel lesions. Obscure gastrointestinal bleeding (OGIB) is one of the most important indications of capsule endoscopy.Capsule endoscopy has a very high diagnostic yield especially if the bleeding is ongoing. This technique appears to be superior to other techniques for the detection of suspected lesions and the source of bleeding. Capsule endoscopy has been shown to change the outcome in patients with obscure gastrointestinal (GI)bleed.

  20. Bleeding from gums: Can it be a dengue

    OpenAIRE

    Rajat Bansal; Purnita Goyel; Dinesh. C. Agarwal

    2014-01-01

    Introduction: Bleeding from gums is a common feature in periodontitis patient. But abnormal bleeding from the gingiva or other areas of the oral mucosa that is difficult to control is an important clinical sign suggesting a hematological disorder. Case Report: A-40-year old male patient reported to our clinic with the chief complaint of acute gingival bleeding. There was continuous bleeding, fever since 3-4 days with weakness, retro orbital pain, and severe backache. Patient gave a history of...

  1. Kinect, a Novel Cutting Edge Tool in Pavement Data Collection

    Science.gov (United States)

    Mahmoudzadeh, A.; Firoozi Yeganeh, S.; Golroo, A.

    2015-12-01

    Pavement roughness and surface distress detection is of interest of decision makers due to vehicle safety, user satisfaction, and cost saving. Data collection, as a core of pavement management systems, is required for these detections. There are two major types of data collection: traditional/manual data collection and automated/semi-automated data collection. This paper study different non-destructive tools in detecting cracks and potholes. For this purpose, automated data collection tools, which have been utilized recently are discussed and their applications are criticized. The main issue is the significant amount of money as a capital investment needed to buy the vehicle. The main scope of this paper is to study the approach and related tools that not only are cost-effective but also precise and accurate. The new sensor called Kinect has all of these specifications. It can capture both RGB images and depth which are of significant use in measuring cracks and potholes. This sensor is able to take image of surfaces with adequate resolution to detect cracks along with measurement of distance between sensor and obstacles in front of it which results in depth of defects. This technology has been very recently studied by few researchers in different fields of studies such as project management, biomedical engineering, etc. Pavement management has not paid enough attention to use of Kinect in monitoring and detecting distresses. This paper is aimed at providing a thorough literature review on usage of Kinect in pavement management and finally proposing the best approach which is cost-effective and precise.

  2. Use of Recycled Aggregate and Fly Ash in Concrete Pavement

    OpenAIRE

    Myle N. James; Wonchang Choi; Taher Abu-Lebdeh

    2011-01-01

    Problem statement: Recycled materials aggregate from the demolished concrete structures and fly ash from burning coal shows the possible application as structural and non structural components in concrete structures. This research aims to evaluate the feasibility of using concrete containing recycled concrete aggregate and fly ash in concrete pavement. Approach: Two water cement ratio (0.45 and 0.55) the compressive strength, modulus of electricity and flexural streng...

  3. Influential Factors on Deicing Performance of Electrically Conductive Concrete Pavement

    Institute of Scientific and Technical Information of China (English)

    TANG Zuquan; QIAN Jueshi; LI Zhuoqiu; WU Chuanming

    2006-01-01

    The deicing experiment of carbon fiber reinforced electrically conductive concrete (CFRC) slab was conducted in laboratory at first, then the deicing process of CFRC pavement was analyzed by means of finite element method (FEM). At last, based on the energy conservation law and the computing results of finite element method, the influential factors including the setting of electric heating layer, environmental temperature, the thickness of ice, material parameters, and deicing power on deicing performance and energy consumption were discussed.

  4. Identifying Fine Aggregates Prone to Polishing in PCC Pavements

    OpenAIRE

    Fowler, David W; Rached, Marc M.

    2012-01-01

    Surface polishing in portland cement concrete (PCC) pavements leads to higher incidences of skid-related accidents on highways. This type of failure is often associated with the usage of softer fine aggregate such as limestone sands. To identify polish resistance aggregates, state agencies like TxDOT have adopted tests such as the acid insoluble residue test (AIR). Since calcium carbonate is soluble in acid, no carbonate sand passes the AIR test which has a minimum limit of 60% in Texas. This...

  5. Pavement wear and airborne dust pollution in Norway

    OpenAIRE

    Snilsberg, Brynhild

    2008-01-01

    In several large cities in Norway the traffic volume is high. The use of studded tires and other friction enhancing measures during winter leads to significant pavement wear, which in turn leads to an increase in the amount of airborne particulate matter, often exceeding the limits set in the ambient air regulation. This represents a nuisance or health risk for people being exposed to the pollution. According to regulations set by the European Union particulate matter is measured and regulate...

  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. Development of a fiber optic pavement subgrade strain measurement system

    Science.gov (United States)

    Miller, Craig Emerson

    2000-11-01

    This dissertation describes the development of a fiber optic sensing system to measure strains within the soil subgrade of highway pavements resulting from traffic loads. The motivation to develop such a device include improvements to: (1)all phases of pavement design, (2)theoretical models used to predict pavement performance, and (3)pavement rehabilitation. The design of the sensing system encompasses selecting an appropriate transducer design as well as the development of optimal optical and demodulation systems. The first is spring based, which attempts to match its spring stiffness to that of the soil-data indicate it is not an optimal transducer design. The second transducer implements anchoring plates attached to two telescoping tubes which allows the soil to be compacted to a desired density between the plates to dictate the transducer's behavior. Both transducers include an extrinsic Fabry- Perot cavity to impose the soil strains onto a phase change of the optical signal propagating through the cavity. The optical system includes a low coherence source and allows phase modulation via path length stretching by adding a second interferometer in series with the transducer, resulting in a path matched differential interferometer. A digitally implemented synthetic heterodyne demodulator based on a four step phase stepping algorithm is used to obtain unambiguous soil strain information from the displacement of the Fabry-Perot cavity. The demodulator is calibrated and characterized by illuminating the transducer with a second long coherence source of different wavelength. The transducer using anchoring plates is embedded within cylindrical soil specimens of varying soil types and soil moisture contents. Loads are applied to the specimen and resulting strains are measured using the embedded fiber optic gage and LVDTs attached to the surface of the specimen. This experimental verification is substantiated using a finite element analysis to predict any differences

  8. Evaluation of pavement skid resistance using high speed texture measurement

    OpenAIRE

    Jay N. Meegoda; Shengyan Gao

    2015-01-01

    Skid resistance is an important parameter for highway designs, construction, management, maintenance and safety. The purpose of this manuscript is to propose the correlation between skid resistance, which is measured as skid resistance trailer, and mean profile depth (MPD) or the macro surface texture, which is measured by vehicle mounted laser, so that highway agencies can predict the skid resistance of pavement without the use of expensive and time consuming skid resistance trailer, which a...

  9. INVESTIGATION OF ASPHALT PAVEMENT WITH ADDED CRUMB RUBBER

    OpenAIRE

    Mandula, Jan; Olexa, Tomaš; Holubka, Mariya; Salaiova, Brigita

    2014-01-01

    Waste tires must be recycled in environmentally safe ways that meet civil engineering concerns while fulfilling standards for construction materials. Used tires can be processed into rubber powders with particle sizes of 0–2 mm, a suitable fine aggregate for mixing into road pavements. We tested asphalt mixtures with rubber added using the dry method, comparing their properties with a traditional mixture. We tested asphalt–rubber mixtures with rubber incorporated at either ambient temperature...

  10. Reinforcing Effects of Carbon Black on Asphalt Binder for Pavement

    OpenAIRE

    Yamaguchi, Katsuyuki; Sasaki, Iwao; Nishizaki, Itaru; Meiarashi, Seishi; Moriyoshi, Akihiro

    2005-01-01

    Carbon black, used as a reinforcing filler for rubber materials, was evaluated for asphalt binders in pavements. Carbon black added to straight asphalt within 20 wt% caused an increase in the elastic modulus and a decrease in the viscosity of the asphalt, especially at temperatures higher than room temperature. Addition of carbon black raised the maximum service temperature of asphalt in the category of the binder performance grade according to the SHRP (Strategic Highway Research Program) sp...

  11. 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...

  12. Structural Design of Asphalt Pavement for Low Cost Rural Roads

    Institute of Scientific and Technical Information of China (English)

    Yuan Goulin; Chen Rongshen

    2006-01-01

    On the basis of the equivalent axle load action frequency, the traffic classifications of rural roads as well as their corresponding types are classified. The asphalt pavement structure, road surface types and thickness of the rural roads are suggested for the various action frequency of the equivalent axle load. Furthermore, the roadbase thickness graphs are provided according to different equivalent axle load action frequency with different roadbed modulus and road surface modulus taken into account.

  13. 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.

  14. Texture friction relationship: from texture empirical decomposition to pavement friction

    OpenAIRE

    Kane, Malal; RADO, Zoltan; CEREZO, Véronique; TIMMONS, Andrew; DO, Minh Tan

    2014-01-01

    This work investigates the friction-texture relationship: starting from a decomposition method of the pavement texture that is part of a new signal processing so called “Huang Hilbert Transformation” to texture parameters-friction relation. This method allows empirical decomposition of the texture profile to a set of basic profiles in a limited number, so called “Intrinsic Mode Functions” or IMF. From the obtained IMFs, a set of four new functions so called “Base...

  15. Integration of Sustainability Rating Tools in Contemporary Pavement Management Systems

    OpenAIRE

    Maher, Michael; Kazmierowski, Tom; Navarra, Michael

    2015-01-01

    There is growing demand around the world for public agencies to implement sustainable initiatives into public infrastructure projects. Sustainability principles need to be integrated seamlessly into all decision making processes, especially when it relates to public expenditures on vital infrastructure. While agreeing with the principles of sustainability, many agencies struggle with how to implement these objectives in a systematic manner. Pavement sustainability can be evaluated using sever...

  16. Methods of Nuclear Medicine in gastrointestinal bleeding detection

    International Nuclear Information System (INIS)

    Several methods used in the diagnostic of gastrointestinal bleeding are presented. Two radioisotopic methods are considered the main ones: coloidal sulphur labeled with technetium-99m, more useful for low and acute bleeding and red blood cells labeled with technetium-99m, adequate for high and intermitent bleeding. (Author)

  17. Scintigraphic detection and localization of gastrointestinal bleeding sites

    International Nuclear Information System (INIS)

    Successful management of acute gastrointestinal (GI) bleeding usually depends on accurate localization of the bleeding site. History and clinical findings are often misleading in determination of the site of hemorrhage. The widespread application of flexible endoscopy and selective arteriography now provide accurate diagnoses for the majority of patients bleeding from the upper GI tract, but lower GI bleeding still poses a serious diagnostic challenge. Endoscopy and barium studies are of limited value in examining the small bowel and colon in the face of active hemorrhage. Arteriography, although successful in many cases (3-5), has limitations. The angiographic demonstration of bleeding is possible only when the injection of contrast material coincides with active bleeding at a rate greater than 0.5 ml/min, and since lower GI bleeding is commonly intermittent rather than continuous, a high rate of negative angiographic examinations has been reported. The diagnosis of lower GI bleeding is usually easy to make. In contrast, localizing the site of bleeding may be extremely difficult. Using the techniques described the nuclear physician may be able to detect the bleeding site precisely. However, if the cautions detailed are not observed, the tracer studies will show GI bleeding, but not at the true bleeding site. This must be carefully understood and avoided. Done correctly, these tests can have a major impact on patient care

  18. 14 CFR 23.1109 - Turbocharger bleed air system.

    Science.gov (United States)

    2010-01-01

    ... Induction System § 23.1109 Turbocharger bleed air system. The following applies to turbocharged bleed air systems used for cabin pressurization: (a) The cabin air system may not be subject to hazardous... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbocharger bleed air system....

  19. Obesity and risk of bleeding : The SMART study

    NARCIS (Netherlands)

    Braekkan, S. K.; van der Graaf, Y.; Visseren, F. L J; Algra, A.

    2016-01-01

    Essentials: Whether obesity protects against clinically relevant bleeding is unclear. We investigated the risk of bleeding according to various measures of obesity in a cohort of 9736 patients. Obesity was not associated with a lower risk of bleeding. The procoagulant profile in obese subjects may n

  20. 14 CFR 23.1111 - Turbine engine bleed air system.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Turbine engine bleed air system. 23.1111 Section 23.1111 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... Induction System § 23.1111 Turbine engine bleed air system. For turbine engine bleed air systems,...

  1. Endoscopic Management of Bleeding Ectopic Varices With Histoacryl

    OpenAIRE

    1999-01-01

    Bleeding from antral and duodenal varices is an uncommon feature in patients with portal hypertension. We report a patient with cirrhosis and portal vein thrombosis, who had a massive bleed from antral and duodenal varices. Bleeding was controlled with endoscopic injection of varices using histoacryl. Endoscopic treatment and the relatively uncommon occurrence of antral and duodenal varices are highlighted.

  2. 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.

  3. Numerical Simulation of Moving Load on Concrete Pavements

    Directory of Open Access Journals (Sweden)

    Lajčáková 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.

  4. 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.

  5. Study the Relationship between Pavement Surface Distress and Roughness Data

    Directory of Open Access Journals (Sweden)

    MubarakiMuhammad

    2016-01-01

    Full Text Available In this paper, pavement sections from the highway connected Jeddah to Jazan were selected and analyzed to investigate the relationship between International Roughness Index (IRI and pavement damage including; cracking, rutting, and raveling. The Ministry of Transport (MOT of Saudi Arabia has been collecting pavement condition data using the Road Surface Tester (RST vehicle. The MOT measures Roughness, Rutting (RUT, Cracking (CRA, raveling (RAV. Roughness measurements are calculated in terms of the International Roughness Index (IRI. The IRI is calculated over equally spaced intervals along the road profile. Roughness measurements are performed at speed between at 80 kilometers per hour. Thus RST vehicle has been used to evaluate highways across the country. The paper shows three relationships including; cracking (CRA verses roughness (IRI, rutting (RUT verses IRI, and raveling (RAV verses IRI. Also, the paper developed two models namely; model relates IRI to the three distress under study, and model relates IRI to ride quality. The results of the analysis claim at 95% confidence that a significant relationship exist between IRI and cracking, and raveling. It’s also shown that rutting did not show significant relationship to IRI values. That’s leads to conclude that the distresses types: cracking and raveling may possibly be described as ride quality distresses at different level of significant. Rutting distress described as non-ride quality type’s distresses.

  6. 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.

  7. Configurations Of Tire Pressure On The Pavement For Commercial Vehicles: Calculation Of The ‘N’ Number And The Consequences On Pavement Performance

    Directory of Open Access Journals (Sweden)

    Paulo Boulos Filho

    2016-07-01

    Full Text Available Road traffic has a high variety of types of vehicles and cargo transported. One of the main difficulties in pavement design is forecasting the changes in traffic over time and evaluating the comparative deterioration power of the various loads with axle and tire settings and different levels of repetition. The road environment in Brazil, as we know, is the main means of the country's cargo transportation. Throughout the 1990s and 2000s the road modal accounted for over 60% of the total cargo transported in the country leaving the unbalanced Brazilian transport matrix with almost exclusive investments in such means of transportation. According to CNT 2012, which conducted a survey in approximately 45% of the paved network, evaluating the pavement functional conditions, traffic signs and geometry, 46% of the country’s road network has some type of deficiency in the pavement. The goal of this work is to contribute to a better understanding of the complex influence of traffic in the design and service life of the pavement. The load pressure of commercial vehicle tires over the pavement has increased in recent decades. A more apparent effect of this increase in tire pressure would be the change in the pavement- tire contact area which in turn may result in an increase in the contact load between tire and pavement and other harmful effects on the structure. This study aims to determine the effect on the calculation of the N number, or the number of solicitations of the standard axle on the road pavement, measuring the overload as a percentage of the legal load indicated by a scale. In short, we calculate how an increase in the overload percentage in comparison with the allowable load will influence the decrease of the calculated durability of the pavement designed for the highway.

  8. Duodenal Bleeding from Metastatic Renal Cell Carcinoma

    Science.gov (United States)

    Rustagi, Tarun; Rangasamy, Priya; Versland, Mark

    2011-01-01

    Massive upper gastrointestinal bleeding due to malignancy is relatively uncommon and the duodenum is the least frequently involved site. Duodenal metastasis is rare in renal cell carcinoma (RCC) and early detection, especially in case of a solitary mass, helps in planning further therapy. We report a case of intractable upper gastrointestinal bleeding from metastatic RCC to the duodenum. The patient presented with melena and anemia, 13 years after nephrectomy for RCC. On esophagogastroduodenoscopy, a submucosal mass was noted in the duodenum, biopsies of which revealed metastatic RCC. In conclusion, metastasis from RCC should be considered in nephrectomized patients presenting with gastrointestinal symptoms and a complete evaluation, especially endoscopic examination followed by biopsy, is suggested. PMID:21577373

  9. Duodenal Bleeding from Metastatic Renal Cell Carcinoma

    Directory of Open Access Journals (Sweden)

    Tarun Rustagi

    2011-04-01

    Full Text Available Massive upper gastrointestinal bleeding due to malignancy is relatively uncommon and the duodenum is the least frequently involved site. Duodenal metastasis is rare in renal cell carcinoma (RCC and early detection, especially in case of a solitary mass, helps in planning further therapy. We report a case of intractable upper gastrointestinal bleeding from metastatic RCC to the duodenum. The patient presented with melena and anemia, 13 years after nephrectomy for RCC. On esophagogastroduodenoscopy, a submucosal mass was noted in the duodenum, biopsies of which revealed metastatic RCC. In conclusion, metastasis from RCC should be considered in nephrectomized patients presenting with gastrointestinal symptoms and a complete evaluation, especially endoscopic examination followed by biopsy, is suggested.

  10. Endovascular management of acute bleeding arterioenteric fistulas

    DEFF Research Database (Denmark)

    Leonhardt, H.; Mellander, S.; Snygg, J.;

    2008-01-01

    The objective of this study was to review the outcome of endovascular transcatheter repair of emergent arterioenteric fistulas. Cases of abdominal arterioenteric fistulas (defined as a fistula between a major artery and the small intestine or colon, thus not the esophagus or stomach), diagnosed....... All had massive persistent bleeding with hypotension despite volume substitution and transfusion by the time of endovascular management. Outcome after treatment of these patients was investigated for major procedure-related complications, recurrence, reintervention, morbidity, and mortality. Mean...... reintervention. The in-hospital mortality was 20% and the 30-day mortality was 40%. The midterm outcome was poor, due to comorbidities or rebleeding, with a mortality of 80% within 6 months. In conclusion, endovascular repair is an efficient and safe method to stabilize patients with life-threatening bleeding...

  11. Duodenal bleeding from metastatic renal cell carcinoma.

    Science.gov (United States)

    Rustagi, Tarun; Rangasamy, Priya; Versland, Mark

    2011-04-20

    Massive upper gastrointestinal bleeding due to malignancy is relatively uncommon and the duodenum is the least frequently involved site. Duodenal metastasis is rare in renal cell carcinoma (RCC) and early detection, especially in case of a solitary mass, helps in planning further therapy. We report a case of intractable upper gastrointestinal bleeding from metastatic RCC to the duodenum. The patient presented with melena and anemia, 13 years after nephrectomy for RCC. On esophagogastroduodenoscopy, a submucosal mass was noted in the duodenum, biopsies of which revealed metastatic RCC. In conclusion, metastasis from RCC should be considered in nephrectomized patients presenting with gastrointestinal symptoms and a complete evaluation, especially endoscopic examination followed by biopsy, is suggested.

  12. 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

  13. Neurenteric Cyst Presenting with Bleeding Per Rectum.

    Science.gov (United States)

    Yadav, Taruna; Parmar, Padam; Rattan, Kamal Nain

    2016-01-01

    Neurenteric cyst in the thoracic cavity may produce a myriad of clinical features. We report a 7-month-old girl who presented with significant bleeding per rectum. On imaging, a mediastinal cystic structure with air-fluid levels was evident with cervico-thoracic vertebral anomalies. The cyst was excised and histopathology showed intestinal mucosal lining with heterotopic pancreatic tissue confirming the diagnosis of neurenteric cyst.

  14. The selective bleed variable cycle engine

    OpenAIRE

    Nascimento, M. A. R.

    1992-01-01

    A new concept in aircraft propulsion is described in this work. In particular, variable jet engine is investigated for supersonic ASTOVL aircraft. This engine is a Selective Bleed Variable Cycle, twin shaft turbofan. At low flight speeds the engine operates as a medium bypass turbofan. At supersonic cruise it operates as low bypass turbofan without reheat. The performance of the engine and its components is analyzed using a novel matching procedure. Off-design engine performance characterist...

  15. Bleeding gums: Duloxetine may be the cause

    Directory of Open Access Journals (Sweden)

    Balhara YPS

    2007-01-01

    Full Text Available Duloxetine is a newly introduced drug. It is being prescribed for the management of diabetic neuropathic pain and major depressive disorder. The most frequently observed adverse events with duloxetine are nausea, dry mouth and somnolence, constipation, diarrhea, decreased appetite, weight loss, feeling of fatigue, dizziness, somnolence, hypohidrosis, decreased libido and erectile dysfunction. One of the patients being prescribed the drug developed bleeding gums on being started with the drug which resolved on stopping it. We hereby report this case.

  16. Otorrhagia bleeding due to leech bite

    OpenAIRE

    Narges Askari; Afrooz Eshaghian

    2012-01-01

    Leeches are blood-sucking hermaphroditic parasites that attach to vertebrate hosts, bite through the skin, and suck out blood. When leeches feed, they secrete an anticoagulant (hirudin), which helps them get a full meal of blood. This is the first report of leech removal from external auditory canal. Previous leech involvement cases were explained in nasopharynx, larynx, pharynx, eye, and gastrointestinal tract. Prominent sign of all cases was active bleeding from the leech attachment site; t...

  17. A Method to Estimate the Dynamic Displacement and Stress of a Multi-layered Pavement with Bituminous or Concrete Materials

    OpenAIRE

    LU, ZHENG; Yao, Hailin; Zhang, JingBo

    2014-01-01

    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...

  18. The role of endoscopy in pediatric gastrointestinal bleeding

    Science.gov (United States)

    Franke, Markus; Geiß, Andrea; Greiner, Peter; Wellner, Ulrich; Richter-Schrag, Hans-Jürgen; Bausch, Dirk; Fischer, Andreas

    2016-01-01

    Background and study aims: Gastrointestinal bleeding in children and adolescents accounts for up to 20 % of referrals to gastroenterologists. Detailed management guidelines exist for gastrointestinal bleeding in adults, but they do not encompass children and adolescents. The aim of this study was to assess gastrointestinal bleeding in pediatric patients and to determine an investigative management algorithm accounting for the specifics of children and adolescents. Patients and methods: Pediatric patients with gastrointestinal bleeding admitted to our endoscopy unit from 2001 to 2009 (n = 154) were identified. Retrospective statistical and neural network analysis was used to assess outcome and to determine an investigative management algorithm. Results: The source of bleeding could be identified in 81 % (n = 124/154). Gastrointestinal bleeding was predominantly lower gastrointestinal bleeding (66 %, n = 101); upper gastrointestinal bleeding was much less common (14 %, n = 21). Hematochezia was observed in 94 % of the patients with lower gastrointestinal bleeding (n = 95 of 101). Hematemesis (67 %, n = 14 of 21) and melena (48 %, n = 10 of 21) were associated with upper gastrointestinal bleeding. The sensitivity and specificity of a neural network to predict lower gastrointestinal bleeding were 98 % and 63.6 %, respectively and to predict upper gastrointestinal bleeding were 75 % and 96 % respectively. The sensitivity and specifity of hematochezia alone to predict lower gastrointestinal bleeding were 94.2 % and 85.7 %, respectively. The sensitivity and specificity for hematemesis and melena to predict upper gastrointestinal bleeding were 82.6 % and 94 %, respectively. We then developed an investigative management algorithm based on the presence of hematochezia and hematemesis or melena. Conclusions: Hematochezia should prompt colonoscopy and hematemesis or melena should prompt esophagogastroduodenoscopy. If no

  19. Bleeding risk in 'real world' patients with atrial fibrillation: comparison of two established bleeding prediction schemes in a nationwide cohort

    DEFF Research Database (Denmark)

    Olesen, J B; Lip, G Y H; Hansen, P R;

    2011-01-01

    Oral anticoagulation (OAC) in patients with atrial fibrillation (AF) is a double-edged sword, because it decreases the risk of stroke at the cost of an increased risk of bleeding. We compared the performance of a new bleeding prediction scheme, HAS-BLED, with an older bleeding prediction scheme, ......, HEMORR(2)HAGES, in a cohort of 'real-world' AF patients....

  20. Endoscopic hemoclip treatment for bleeding peptic ulcer

    Institute of Scientific and Technical Information of China (English)

    Yung Chih Lai; Sien Sing Yang; Chi Hwa Wu; Tzen Kwan Chen

    2000-01-01

    AIM To evaluate the efficacy of endoscopic hemoclip in the treatment of bleeding peptic ulcer.METHODS Totally, 40 patients with F1a and F1b hemorrhagic activity of peptic ulcers were enrolled in this uncontrolled prospective study for endoscopic hemoclip treatment. We used a newly developed rotatable clip-device for the application of hemoclip (MD850) to stop bleeding. Endoscopy was repeated if there was any sign or suspicion of rebleeding, and reclipping was performed if necessary and feasible.RESULTS Initial hemostatic rate by clipping was 95%, and rebleeding rate was only 8%.Ultimate hemostatic rates were 87%, 96%, and 93% in the F1a and F1b subgroups, and total cases, respectively. In patients with shock on admission, hemoclipping achieved ultimate hemostasis of 71% and 83% in F1a and F1b subgroups, respectively. Hemostasis reached 100% in patients without shock regardless of hemorrhagic activity being F1a or F1b. The average number of clips used per case was 3.0 (range 2- 5). Spurting bleeders required more clips on average than did oozing bleeders (3.4 versus 2.8 ). We observed no obvious complications, no tissue injury, or impairment of ulcer healing related to hemoclipping.CONCLUSION Endoscopic hemoclip placement is an effective and safe method. With the improvement of the clip and application device,the procedure has become easier and much more efficient. Endoscopic hemoclipping deserves further study in the treatment of bleeding peptic ulcers.

  1. [Obscure digestive bleeding by ileal carcinoid tumor].

    Science.gov (United States)

    Nelly Manrique, María; Frisancho, Oscar; Zumaeta, Eduardo; Palomino, Américo; Rodriguez, César

    2011-01-01

    The patient is an 82 year-old female with a history of osteoarthritis, hypothyroidism and anemia for 14 years (receiving blood transfusions). She was admited to our hospital with a nine months history of malaise, anorexia, fatigue and weakness, associated with intermitten episodes of abdominal pain. She was diagnosed anemia and occult blood positive stools. Physical examination revealed a patient in generally fair condition, obese, with mild edema of lower limbs, no changes in the evaluation of chest, cardiovascular, abdomen, etc. Laboratory data was unremarkable, except for iron deficiency anemia. The upper endoscopy showed duodenal ulcer scar, fundic polyposis and chronic gastritis. Colonoscopy revealed some diverticula, a small sessile polyp and internal hemorrhoids. The diagnosis of obscure gastrointestinal bleeding was made. The CT scan of the abdomen showed gallstones and fatty liver; a radiograph of intestinal transit detected a lesion apparently protruded intestinal loop for distal jejunum; enteroscopy was performed (with one team ball) anterograde and retrograde achieving assess distal jejunum and distal ileum without observing any injuries. The study of capsule endoscopy showed a polypoid tumor intestinal with evidence of having bleeding. Surgery detected the tumor in proximal ileum. The surgical specimen findings showed three tumors 0.7 mm, 10 mm and 15 mm on the proximal ileum. The microscopic examination revealed that these lesions were neuroendocrine tumors (carcinoid). The Ileal carcinoid tumor may rarely presented with obscure gastrointestinal bleeding. PMID:21544161

  2. Rare bleeding disorders: diagnosis and treatment.

    Science.gov (United States)

    Palla, Roberta; Peyvandi, Flora; Shapiro, Amy D

    2015-03-26

    Despite the worldwide prevalence of rare bleeding disorders (RBDs), knowledge of these conditions and their management is suboptimal; health care professionals often have little diagnostic and treatment experience with variable access to diagnostic modalities required for accurate identification. Therefore, patients often experience morbidity and mortality due to delayed diagnosis. As RBDs represent a small potential commercial market, few, if any, specific therapies exist for these conditions. As a result, affected individuals commonly face delayed diagnosis, incomplete laboratory evaluation, and limited treatment options. Standardization and customization of coagulation assays, full genome sequencing, and global clotting assays will significantly improve diagnosis of patients with RBDs. In addition, new therapeutic modalities, both recombinant and plasma derived, are emerging, at least in developed countries. Registries and clinical trials have demonstrated decreased bleeding and improved outcomes when patients are appropriately diagnosed and properly treated. Expansion and harmonization of international registries has been initiated to correlate genotype, laboratory, and clinical phenotypes including bleeding severity to improve the diagnosis and therapeutic approach. This review focuses on the latest advances in our understanding, diagnosis, and treatment of RBDs. PMID:25712993

  3. Investigation of mechanical properties of pavement through electromagnetic techniques

    Science.gov (United States)

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

    2014-05-01

    Ground-penetrating radar (GPR) is considered as one of the most flexible geophysical tools that can be effectively and efficiently used in many different applications. In the field of pavement engineering, GPR can cover a wide range of uses, spanning from physical to geometrical inspections of pavements. Traditionally, such inferred information are integrated with mechanical measurements from other traditional (e.g. plate bearing test) or non-destructive (e.g. falling weight deflectometer) techniques, thereby resulting, respectively, in time-consuming and low-significant measurements, or in a high use of technological resources. In this regard, the new challenge of retrieving mechanical properties of road pavements and materials from electromagnetic measurements could represent a further step towards a greater saving of economic resources. As far as concerns unpaved and bound layers it is well-known that strength and deformation properties are mostly affected, respectively, by inter-particle friction and cohesion of soil particles and aggregates, and by bitumen adhesion, whose variability is expressed by the Young modulus of elasticity. In that respect, by assuming a relationship between electromagnetic response (e.g. signal amplitudes) and bulk density of materials, a reasonable correlation between mechanical and electric properties of substructure is therefore expected. In such framework, a pulse GPR system with ground-coupled antennae, 600 MHz and 1600 MHz centre frequencies was used over a 4-m×30-m test site composed by a flexible pavement structure. The horizontal sampling resolution amounted to 2.4×10-2 m. A square regular grid mesh of 836 nodes with a 0.40-m spacing between the GPR acquisition tracks was surveyed. Accordingly, a light falling weight deflectometer (LFWD) was used for measuring the elastic modulus of pavement at each node. The setup of such instrument consisted of a 10-kg falling mass and a 100-mm loading plate so that the influence domain

  4. 23 CFR Appendix to Subpart F of... - Alternate Method of Determining the Color of Retroreflective Sign Materials and Pavement Marking...

    Science.gov (United States)

    2010-04-01

    ... Retroreflective Sign Materials and Pavement Marking Materials Appendix to Subpart F of Part 655 Highways FEDERAL... Pavement Marking Materials 1. Although the FHWA Color Tolerance Charts depreciate the use of... for Retroreflective Pavement Marking Material With CIE 2° Standard Observer and 45/0 (0/45)...

  5. Scintigraphic localisation of colonic bleeding; Scintigrafisk lokalisasjon av colonbloedning

    Energy Technology Data Exchange (ETDEWEB)

    Aspevik, Ranveig K.; Miskowiak, Jerzy; I Bud, Margreta

    2001-07-01

    Background. Endoscopy and occasionally X-ray studies are used to discover the focus of a gastrointestinal bleeding. Material and methods. We describe a case of severe gastrointestinal bleeding where these methods failed. Scintigraphy after labelling of erythrocytes with 99m technetium was performed in a continuos manner for 60 minutes. Scintigrams were also taken three, ten and 23 hours after the injection. Results. No bleeding was revealed after 60 minutes but two hours later a slight radioactivity was encountered in the right part of the abdomen and the later images localised the bleeding in the right colon. The bleeding ceased after right-sided hemicolectomy. Interpretation. Scintigraphy is of value in localisation of gastrointestinal bleeding and should be performed in a continuos manner until the bleeding focus is localised. Secretion of unbound technetium through the mucosa of the stomach and its presence in the urinary tract should be taken in account.

  6. FORECASTING OF DURABILITY OF ASPHALT PAVEMENT ON THE BASIS OF LEVELS OF THEIR VIBRATION LOADING

    Directory of Open Access Journals (Sweden)

    V. A. Osinovskaya

    2015-01-01

    Full Text Available The problem of low durability of flexible pavement is one of the most important problems of road economy. For example, the actual service life of asphalt pavement in Russia about 3 … 5 years. The bad condition of highways is an obstacle for the development of the national economy and leads to a significant annual economic losses.At present, this problem has no exact solution. Even at the seeming good road conditions of Europe and America the problem of low durability is no less important in these countries. And this problem becomes more and more actual every year.Our scientific researches allowed to make a hypothesis that the projected of pavements are not have the necessary durability yet not of a stage of designing because in strength calculations did not take into account the vibration of road constructions.Very actual the vibration loading becomes today as is now significantly changed the nature of loading of pavements. As a result the deflections of a pavements are reduced, but the increased vibration of pavements accelerated processes of destruction and significantly reduced durability.The theory of vibration destruction developed by the author allows to adjust the vibration, to form the vibration resistance pavements, and also to forecast a residual life of pavements that will more effectively develop repair actions.

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

    Directory of Open Access Journals (Sweden)

    Saurabh Jain

    2013-09-01

    Full Text Available 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 preferred over cement concrete roads as they have a great advantage that these can be strengthened and improved in stages with the growth of traffic and also their surfaces can be milled and recycled for rehabilitation. The flexible pavements are less expensive also with regard to initial investment and maintenance. Although Rigid pavement is expensive but have less maintenance and having good design period. The economic part are carried out for the design pavement of a section by using the result obtain by design method and their corresponding component layer thickness. It can be done by drawing comparisons with the standard way and practical way. This total work includes collection of data analysis various flexible and rigid pavement designs and their estimation procedure are very much useful to engineer who deals with highways.

  8. Quantifying Evaporation and Evaluating Runoff Estimation Methods in a Permeable Pavement System

    Science.gov (United States)

    The U.S. Environmental Protection Agency constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable pavement in the parking lanes which were designed to receive run-on from the impervious hot-mix asphalt driving lanes. Twelve lined permeable pavement sec...

  9. Active zone impact on deformation state of non-rigid pavement

    Science.gov (United States)

    Mandula, Ján

    2014-06-01

    The paper deals with the design of non-rigid pavement, with emphasis on the effect of active zone on its deformation state. The concepts of determination of active zone are described. The results of numerical modelling of pavement laying on elastic subgrade are presented in the paper

  10. Active zone impact on deformation state of non-rigid pavement

    Directory of Open Access Journals (Sweden)

    Mandula Ján

    2014-06-01

    Full Text Available The paper deals with the design of non-rigid pavement, with emphasis on the effect of active zone on its deformation state. The concepts of determination of active zone are described. The results of numerical modelling of pavement laying on elastic subgrade are presented in the paper

  11. Characterization and modelling of self healing of bituminous materials towards durable asphalt pavement

    NARCIS (Netherlands)

    Qiu, J.; Van de Ven, M.F.C.; Schlangen, H.E.J.G.; Wu, S.; Molenaar, A.A.A.

    2012-01-01

    The traffic volume and the number of heavy vehicles are growing enormously nowadays. There is a need for designing a durable asphalt pavement with innovative technologies. Pavement structures and materials with self healing and self repairing capability are believed to be very useful in such a syste

  12. 23 CFR 971.208 - Federal lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ...,” AASHTO, 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... 23 Highways 1 2010-04-01 2010-04-01 false Federal lands pavement management system (PMS). 971.208... lands pavement management system (PMS). In addition to the requirements provided in § 971.204, the...

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

    Science.gov (United States)

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

  14. 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…

  15. 23 CFR 973.208 - Indian lands pavement management system (PMS).

    Science.gov (United States)

    2010-04-01

    ..., 2001, is available for inspection as prescribed at 49 CFR part 7. It is also available from the... 23 Highways 1 2010-04-01 2010-04-01 false Indian lands pavement management system (PMS). 973.208... PROGRAM Bureau of Indian Affairs Management Systems § 973.208 Indian lands pavement management system...

  16. 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.

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

    Science.gov (United States)

    Yati Katman, Herda; Rasdan Ibrahim, Mohd; Yazip Matori, Mohd; Norhisham, Shuhairy; Ismail, Norlela

    2013-06-01

    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.

  18. RoADS: a road pavement monitoring system for anomaly detection using smart phones

    NARCIS (Netherlands)

    Seraj, Fatjon; Zwaag, van der Berend Jan; Dilo, Arta; Luarasi, Tamara; Havinga, Paul; Atzmueller, Martin; Chin, Alvin; Janssen, Frederik; Schweizer, Immanuel; Trattner, Christoph

    2016-01-01

    Monitoring the road pavement is a challenging task. Authorities spend time and finances to monitor the state and quality of the road pavement. This paper investigate road surface monitoring with smartphones equipped with GPS and inertial sensors: accelerometer and gyroscope. In this study we descri

  19. Integrated wave propagation devices for quality control or diagnostics of pavements

    Science.gov (United States)

    Nazarian, Soheil; Yuan, Deren; Baker, Mark R.; Crain, Kevin

    1996-11-01

    Seismic Pavement Analyzer and a portable version of it have been extensively used for quality control and monitoring the structural condition of pavements. With them, a pavement can be tested at closely spaced points and at a fraction of the cost and time of coring. The main tests used are the impact echo for determining the thickness of the slab, ultrasonic body wave and ultrasonic surface wave for determining the moduli of top layer, impulse response for determining the condition of subgrade, and SASW method for determining the modulus profile of pavement. Based on extensive field testing on numerous types of base and subgrade,the techniques in general, and the two devices in particular are quite suitable for many quality and pavement evaluation projects.

  20. 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.

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

    Science.gov (United States)

    Wang, Hong; Wu, Shaopeng; Chen, Mingyu; Zhang, Yuan

    2010-05-01

    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.

  2. Comparison of detectable bleeding rates of radiopharmaceuticals for localization of gastrointestinal bleeding in sheep using a closed system

    Energy Technology Data Exchange (ETDEWEB)

    Owunwanne, A.; Sadek, S.; Yacoub, T.; Awdeh, M.; Abdel-Dayem, H.M. (Kuwait Univ. (Kuwait). Dept. of Nuclear Medicine); Al-Wafai, I.; Vallgren, S. (Kuwait Univ. (Kuwait). Dept. of Surgery)

    1989-06-01

    The closed experimental animal model system was used to compare the detectable gastrointestinal (GI) bleeding rates of {sup 99m}Tc-DTPA, {sup 99m}Tc-RBCs and {sup 99m}Tc tin colloid in sheep. The three radiopharmaceuticals were used to detect the upper GI bleeding sites at rates of 0.57 and 0.25 ml/min. At the lower bleeding rate of 0.1 ml/min, both {sup 99m}Tc-DTPA and {sup 99m}Tc-RBCs were successful in detecting the bleeding site. At the lowest rate of 0.07 ml/min only {sup 99m}Tc-DTPA was successful in detecting the bleeding site. The results indicate that {sup 99m}Tc-DTPA is the most useful {sup 99m}Tc radiopharmaceutical for detecting the upper GI bleeding site at the slowest bleeding rate studied. (orig.).

  3. Use of Ground Penetrating Radar at the FAA's National Airport Pavement Test Facility

    Science.gov (United States)

    Injun, Song

    2015-04-01

    The Federal Aviation Administration (FAA) in the United States has used a ground-coupled Ground Penetrating Radar (GPR) at the National Airport Pavement Test Facility (NAPTF) since 2005. One of the primary objectives of the testing at the facility is to provide full-scale pavement response and failure information for use in airplane landing gear design and configuration studies. During the traffic testing at the facility, a GSSI GPR system was used to develop new procedures for monitoring Hot Mix Asphalt (HMA) pavement density changes that is directly related to pavement failure. After reviewing current setups for data acquisition software and procedures for identifying different pavement layers, dielectric constant and pavement thickness were selected as dominant parameters controlling HMA properties provided by GPR. A new methodology showing HMA density changes in terms of dielectric constant variations, called dielectric sweep test, was developed and applied in full-scale pavement test. The dielectric constant changes were successfully monitored with increasing airplane traffic numbers. The changes were compared to pavement performance data (permanent deformation). The measured dielectric constants based on the known HMA thicknesses were also compared with computed dielectric constants using an equation from ASTM D4748-98 Standard Test Method for Determining the Thickness of Bound Pavement Layers Using Short-Pulse Radar. Six inches diameter cylindrical cores were taken after construction and traffic testing for the HMA layer bulk specific gravity. The measured bulk specific gravity was also compared to monitor HMA density changes caused by aircraft traffic conditions. Additionally this presentation will review the applications of the FAA's ground-coupled GPR on embedded rebar identification in concrete pavement, sewer pipes in soil, and gage identifications in 3D plots.

  4. Application of matter-element analysis based on entropy right to evaluate the pavement condition in permafrost region

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Evaluation of pavement performance is one of the most important issues in a pavement-management system.By employing the concept of entropy,the matter-element model for evaluating pavement is established,and the weights of the evaluation indices are obtained from surveying data.By calculating the degree of dependence of the matter-element model,the pavement performance evaluation can be obtained by this method.The results show that the matter-element model based on entropy right has good performance for evaluating the pavement condition in permafrost region.

  5. Spectrum of histopathological findings in postmenopausal bleeding

    International Nuclear Information System (INIS)

    To determine the frequencies of histopathological findings in endometrial and endocervical biopsy samples with clinical history of Postmenopausal Bleeding (PMB). Study Design: Descriptive cross-sectional study. Place and Duration of Study: Section of Histopathology, Department of Pathology and Laboratory Medicine, The Aga Khan University Hospital, Karachi, from February 2012 to January 2013. Methodology: A total of 157 consecutive endometrial and endocervical biopsy specimens with history of postmenopausal bleeding were included. After microscopic examination, frequencies of histological findings in different age groups were generated. Chi-square and independent sample t-tests were applied to see whether the difference was significant which was set at p < 0.05. Results: One hundred and twenty-one (77.1%) specimens showed benign pathologies while 36 (22.9%) were malignant. Endometrial polyp was seen in 67 (42.7%) cases followed by endometrial carcinomas in 25 (15.9%), endometrial hyperplasia in 21 (13.4%), cervical carcinoma in 12 (7.6%) and cervical polyps in 9 (5.7%) cases. Ahighly significant increase in the percentage of malignant and pre-malignant lesions was seen with increasing age group (p < 0.001). Mean age of patients with type-2 endometrial carcinoma was higher than type-1 endometrial carcinoma but statistical significance was not observed (70.2 ± 6.5 vs. 61.8 ± 9.1 years respectively, p=0.069). Conclusion: Although benign pathologies were more common in postmenopausal bleeding but the collective proportion of endometrial and cervical malignancies and pre-malignant conditions was quite high. Therefore, PMB should be urgently evaluated for cause and early commencement of treatment. (author)

  6. Assessment of porous asphalt pavement performance: hydraulics and water quality

    Science.gov (United States)

    Briggs, J. F.; Ballestero, T. P.; Roseen, R. M.; Houle, J. J.

    2005-05-01

    The objective of this study is to focus on the water quality treatment and hydraulic performance of a porous asphalt pavement parking lot in Durham, New Hampshire. The site was constructed in October 2004 to assess the suitability of porous asphalt pavement for stormwater management in cold climates. The facility consists of a 4-inch asphalt open-graded friction course layer overlying a high porosity sand and gravel base. This base serves as a storage reservoir in-between storms that can slowly infiltrate groundwater. Details on the design, construction, and cost of the facility will be presented. The porous asphalt pavements is qualitatively monitored for signs of distress, especially those due to cold climate stresses like plowing, sanding, salting, and freeze-thaw cycles. Life cycle predictions are discussed. Surface infiltration rates are measured with a constant head device built specifically to test high infiltration capacity pavements. The test measures infiltration rates in a single 4-inch diameter column temporarily sealed to the pavement at its base. A surface inundation test, as described by Bean, is also conducted as a basis for comparison of results (Bean, 2004). These tests assess infiltration rates soon after installation, throughout the winter, during snowmelt, after a winter of salting, sanding, and plowing, and after vacuuming in the spring. Frost penetration into the subsurface reservoir is monitored with a frost gauge. Hydrologic effects of the system are evaluated. Water levels are monitored in the facility and in surrounding wells with continuously logging pressure transducers. The 6-inch underdrain pipe that conveys excess water in the subsurface reservoir to a riprap pad is also continuously monitored for flow. Since porous asphalt pavement systems infiltrate surface water into the subsurface, it is important to assess whether water quality treatment performance in the subsurface reservoir is adequate. The assumed influent water quality is

  7. An Unusual Case of Gastrointestinal Bleeding

    Directory of Open Access Journals (Sweden)

    Kristin N. Fiorino

    2011-01-01

    Full Text Available A 10-year-old boy presented with a 3-day history of worsening abdominal pain, fever, emesis and melena. Abdominal ultrasound revealed a right upper quadrant mass that was confirmed by computed tomography angiogram (CTA, which showed an 8 cm well-defined retroperitoneal vascular mass. 123Iodine metaiodobenzylguanidine (123MIBG scan indicated uptake only in the abdominal mass. Subsequent biopsy revealed a paraganglioma that was treated with chemotherapy. This case represents an unusual presentation of a paraganglioma associated with gastrointestinal (GI bleeding and highlights the utility of CTA and 123MIBG in evaluation and treatment.

  8. Reoperation for bleeding in cardiac surgery

    DEFF Research Database (Denmark)

    Kristensen, Katrine Lawaetz; Rauer, Line Juul; Mortensen, Poul Erik;

    2012-01-01

    bleeding, we aim to identify risk factors that predict reoperation. A total of 1452 consecutive patients undergoing cardiac surgery using extracorporeal circulation (ECC) between November 2005 and December 2008 at OUH were analysed. Statistical tests were used to identify risk factors for reoperation. We...... after cardiac surgery was low ejection fraction, high EuroSCORE, procedures other than isolated CABG, elongated time on ECC, low body mass index, diabetes mellitus and preoperatively elevated s-creatinine. Reoperated patients significantly had a greater increase in postoperative s-creatinine and higher...

  9. Devil's claw root: ulcers and gastrointestinal bleeding?

    Science.gov (United States)

    2013-12-01

    Harpagophytum procumbens, or devil's claw, is an African plant whose root is used to relieve minor joint symptoms. Several cases of gastrointestinal bleeding associated with the use of devil's claw root have been reported. A systematic review of the adverse effects of devil's claw root in about 20 randomised, double-blind, placebo-controlled clinical trials showed mainly gastrointestinal effects: gastralgia and dyspepsia. In practice, devil's claw root exposes patients to the risk of sometimes serious upper gastrointestinal disorders, yet has no established efficacy beyond a placebo effect. It is best avoided. PMID:24600731

  10. Numerical modeling of inelastic structures at loading of steady state rolling. Thermo-mechanical asphalt pavement computation

    Science.gov (United States)

    Wollny, Ines; Hartung, Felix; Kaliske, Michael

    2016-05-01

    In order to gain a deeper knowledge of the interactions in the coupled tire-pavement-system, e.g. for the future design of durable pavement structures, the paper presents recent results of research in the field of theoretical-numerical asphalt pavement modeling at material and structural level, whereby the focus is on a realistic and numerically efficient computation of pavements under rolling tire load by using the finite element method based on an Arbitrary Lagrangian Eulerian (ALE) formulation. Inelastic material descriptions are included into the ALE frame efficiently by a recently developed unsplit history update procedure. New is also the implementation of a viscoelastic cohesive zone model into the ALE pavement formulation to describe the interaction of the single pavement layers. The viscoelastic cohesive zone model is further extended to account for the normal pressure dependent shear behavior of the bonding layer. Another novelty is that thermo-mechanical effects are taken into account by a coupling of the mechanical ALE pavement computation to a transient thermal computation of the pavement cross-section to obtain the varying temperature distributions of the pavement due to climatic impact. Then, each ALE pavement simulation considers the temperature dependent asphalt material model that includes elastic, viscous and plastic behavior at finite strains and the temperature dependent viscoelastic cohesive zone formulation. The temperature dependent material parameters of the asphalt layers and the interfacial layers are fitted to experimental data. Results of coupled tire-pavement computations are presented to demonstrate potential fields of application.

  11. Asphaltic concrete overlays of rigid and flexible pavements

    Science.gov (United States)

    Kinchen, R. W.; Temple, W. H.

    1980-10-01

    The development of a mechanistic approach to overlay thickness selection is described. The procedure utilizes a deflection analysis to determine pavement rehabilitation needs. Design guides for selecting the overlay thickness are presented. Tolerable deflection-traffic load relationships and the deflection attenuation properties of asphaltic concrete were developed, representing the subgrade support conditions and properties of materials used in Louisiana. All deflection measurements on asphaltic concrete were corrected for the effect of temperature. Deflection measurements taken before and after overlay were also adjusted to minimize the effects of seasonal subgrade moisture variation.

  12. Synthesis report: D-cracking in portland cement concrete pavements

    Science.gov (United States)

    Thompson, S. R.; Olsen, M. P. J.; Dempsey, B. J.

    1980-06-01

    The mechanisms and testing procedures for D-cracking in portland cement concrete pavements are examined. Benefication procedures are also investigated. The three general responses to freezing in the aggregate/paste system include elastic accommodation, high internal pressure, and high external pressure. It is found that the critical aggregate parameters influencing D-cracking are degree of saturation, maximum particle size, permeability, porosity, and pore size distribution. Evaluation of present laboratory testing procedures indicated that the ASTM C666, VPI slow-cool, Mercury Porosimetry, and Iowa Pore Index Tests correlated the best with field performance of concrete with respect to D-cracking.

  13. Upper gastrointestinal bleeding etiology score for predicting variceal and non-variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    Supot Pongprasobchai; Sireethorn Nimitvilai; Jaroon Chasawat; Sathaporn Manatsathit

    2009-01-01

    AIM: To identify clinical parameters, and develop an Upper Gastrointesinal Bleeding (UGIB) Etiology Score for predicting the types of UGIB and validate the score.METHODS: Patients with UGIB who underwent endoscopy within 72 h were enrolled. Clinical and basic laboratory parameters were prospectively collected.Predictive factors for the types of UGIB were identified by univariate and multivariate analyses and were used to generate the UGIB Etiology Score. The best cutoff of the score was defined from the receiver operating curve and prospectively validated in another set of patients with UGIB.RESULTS: Among 261 patients with UGIB, 47 (18%) had variceal and 214 (82%) had non-variceal bleeding.Univariate analysis identified 27 distinct parameters significantly associated with the types of UGIB. Logistic regression analysis identified only 3 independent factors for predicting variceal bleeding;previous diagnosis of cirrhosis or signs of chronic liver disease (OR 22.4, 95% CI 8.3-60.4, P < 0.001), red vomitus (OR4.6, 95% CI 1.8-11.9, P = 0.02), and red nasogastric (NG) aspirate (OR 3.3, 95% CI 1.3-8.3, P = 0.011).The UGIB Etiology Score was calculated from (3.1 x previous diagnosis of cirrhosis or signs of chronic liver disease) + (1.5 × red vornitus) + (1.2 × red NG aspirate), when 1 and 0 are used for the presence and absence of each factor, respectively. Using a cutoff ≥ 3.1, the sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) in predicting variceal bleeding were 85%, 81%,82%, 50%, and 96%, respectively. The score was prospectively validated in another set of 195 UGIB cases (46 variceal and 149 non-variceal bleeding). The PPV and NPV of a score ≥3.1 for variceal bleeding were 79% and 97%, respectively.CONCLUSION: The UGIB Etiology Score, composed of 3 parameters, using a cutoff ≥ 3.1 accurately predicted variceal bleeding and may help to guide the choice of initial therapy for UGIB before endoscopy.

  14. [EMERGENCY TREATMENT OF BLEEDING IN PATIENTS TAKING WARFARIN].

    Science.gov (United States)

    Prasolov, N V; Shulutko, E M; Bulanov, A Yu; Yatskov, K V; Shcherbakov, O V

    2015-01-01

    Anticoagulant therapy with vitamin K antagonists (AVK) is an effective treatment and prevention of thrombosis. One of the major disadvantages of the AVK is a risk for serious bleeding. Prothrombin complex concentrates (PCC), fresh frozen plasma (FFP) and vitamin K1 are available for control of these situations. The experience of special team ofthe Scientific Center for Hematology was the basis for presented retrospective study. Three regimens of warfarin-related bleeding were compared: PCC+ VK for several bleeding, FFP+ VK for different clinical situations and VKfor light bleeding. PCC showed himself as effective and safe hemostatic agent. Transfusions of FFP were sometimes not effective, sometimes led to TACO. Supplementation of vitamin K1 for patients of I and II groups provided more stable control of hemostasis. In III group VK vas effective to stop bleeding. Two impotent sings for conclusion: necessary of laboratory monitoring, TEG first of all; individual balance of hemostasis base of bleeding or thrombotic risks.

  15. Bioengineering factor Xa to treat bleeding.

    Science.gov (United States)

    Camire, Rodney M

    2016-05-01

    There is a clinical need to develop safe and rapid therapeutic strategies to control bleeding arising from a host of emergent situations. Over the past several years our laboratory has developed novel zymogen-like FXa variants and tested their safety and efficacy using hemophilia as a model system. The variants have a spectrum of properties resulting from an amino acid change at the N-terminus of the heavy chain that alters a critical conformational change. These properties, which include resistance to plasma protease inhibitors, low activity in the absence of FVa, and rescue of low activity upon incorporation in prothrombinase, yield remarkably effective pro-hemostatic agents. The FVa-dependent restoration of activity is a key aspect to their efficacy and also contributes to localizing the variants to the site of vascular injury. While pre-clinical data support their use in the setting of hemophilia, they have the potential to act as rapid pro-hemostatic agents for the treatment of a range of bleeding conditions. This review will discuss the biochemical properties of these FXa zymogen-like variants and their in vivo characterization. PMID:27207419

  16. Otorrhagia bleeding due to leech bite

    Directory of Open Access Journals (Sweden)

    Narges Askari

    2012-01-01

    Full Text Available Leeches are blood-sucking hermaphroditic parasites that attach to vertebrate hosts, bite through the skin, and suck out blood. When leeches feed, they secrete an anticoagulant (hirudin, which helps them get a full meal of blood. This is the first report of leech removal from external auditory canal. Previous leech involvement cases were explained in nasopharynx, larynx, pharynx, eye, and gastrointestinal tract. Prominent sign of all cases was active bleeding from the leech attachment site; that stopped with leech removal. A 24-year-old man was presented to Al-Zahra hospital with left otorrhagia and otalgia from 2 days ago. After suction of ear a small soft foreign body was seen in the external ear near the tympanic membrane, then the ear filled with glycerine phenice, the patient explained decreased movement of foreign body. Four hours later the bloody discharge stopped and otalgia decreased. After suction of clots, a leech was extruded from external auditory canal by alligator. Leech infestation is a rare cause of otorrhagia and should be suspected in the endemic region in all of unusual bleeding; it can be diagnosed and treated by exact inspection and removal.

  17. Effects of cross-anisotropy and stress-dependency of pavement layers on pavement responses under dynamic truck loading

    Directory of Open Access Journals (Sweden)

    Rafiqul A. Tarefder

    2016-06-01

    Full Text Available Previous studies by the authors have determined pavement responses under dynamic loading considering cross-anisotropy in one layer only, either the cross-anisotropic viscoelastic asphalt concrete (AC layer or the cross-anisotropic stress-dependent base layer, but not both. This study evaluates pavement stress–strain responses considering cross-anisotropy in all layers, i.e. AC, base and subbase, using finite element modeling (FEM technique. An instrumented pavement section on Interstate I-40 near Albuquerque, New Mexico was used in ABAQUS framework as model geometry. Field asphalt cores were collected and tested in the laboratory to determine the cross-anisotropy (n-values defined by horizontal to vertical modulus ratio, and other viscoelastic parameters as inputs of the model incorporated through user defined material interface (UMAT functionality in ABAQUS. Field base and subbase materials were also collected and tested in the laboratory to determine stress-dependent nonlinear elastic model parameters, as inputs of the model, again incorporated through UMAT. The model validation task was carried out using field-measured deflections and strain values under falling weight deflectometer (FWD loads at the instrumented section. The validated model was then subjected to an actual truck loading for studying cross-anisotropic effects. It was observed that horizontal tensile strain at the bottom of the AC layer and vertical strains in all layers decreased with an increase in n-value of the asphalt layer, from n < 1 (anisotropy to n=1 (isotropy. This indicates that the increase in horizontal modulus caused the decrease in layer strains. It was also observed that if the base and subbase layers were considered stress-dependent instead of linear elastic unbound layers, the horizontal tensile strain at the bottom of the asphalt layer increased and vertical strains on top of the base and subbase also increased.

  18. Effects of cross-anisotropy and stress-dependency of pavement layers on pavement responses under dynamic truck loading

    Institute of Scientific and Technical Information of China (English)

    Rafiqul A. Tarefder; Mesbah U. Ahmed; Asifur Rahman

    2016-01-01

    Previous studies by the authors have determined pavement responses under dynamic loading consid-ering cross-anisotropy in one layer only, either the cross-anisotropic viscoelastic asphalt concrete (AC) layer or the cross-anisotropic stress-dependent base layer, but not both. This study evaluates pavement stressestrain responses considering cross-anisotropy in all layers, i.e. AC, base and subbase, using finite element modeling (FEM) technique. An instrumented pavement section on Interstate I-40 near Albu-querque, New Mexico was used in ABAQUS framework as model geometry. Field asphalt cores were collected and tested in the laboratory to determine the cross-anisotropy (n-values) defined by horizontal to vertical modulus ratio, and other viscoelastic parameters as inputs of the model incorporated through user defined material interface (UMAT) functionality in ABAQUS. Field base and subbase materials were also collected and tested in the laboratory to determine stress-dependent nonlinear elastic model pa-rameters, as inputs of the model, again incorporated through UMAT. The model validation task was carried out using field-measured deflections and strain values under falling weight deflectometer (FWD) loads at the instrumented section. The validated model was then subjected to an actual truck loading for studying cross-anisotropic effects. It was observed that horizontal tensile strain at the bottom of the AC layer and vertical strains in all layers decreased with an increase in n-value of the asphalt layer, from n<1 (anisotropy) to n ¼ 1 (isotropy). This indicates that the increase in horizontal modulus caused the decrease in layer strains. It was also observed that if the base and subbase layers were considered stress-dependent instead of linear elastic unbound layers, the horizontal tensile strain at the bottom of the asphalt layer increased and vertical strains on top of the base and subbase also increased.

  19. Bleeding and Filtration of Cement-Based Grout

    OpenAIRE

    Draganovic, Almir

    2009-01-01

    Grouting is a common method of sealing rock around tunnels to reduce or stop water inflow. Successful grouting significantly minimizes the maintenance cost and safety of the tunnel. Some questions about bleeding and penetrability of the grouts have to be examined more closely to carry out a successful grouting. Bleeding of cement-based grout is a complex problem. Measuring methods used today originate from the measuring of the bleeding of cement pastes used in ordinary building industry. Whet...

  20. Performance analysis of bleed condenser used in Indian PHWR

    International Nuclear Information System (INIS)

    Condensation of hot two phase bleed from the Primary Heat Transport (PHT) system is carried out by two different cooling modes in the bleed condenser of Indian PHWRs. These are the reflux and spray cooling modes. A computer code has been developed to predict the performance of bleed condensers used in Indian PHWRs for the above two cooling modes. Using the computer code the performance analysis was carried out for the reflux cooling and spray cooling modes separately. (author). 19 refs., 8 figs

  1. Gastrointestinal bleeding 30 years after a complicated cholecystectomy

    Institute of Scientific and Technical Information of China (English)

    Thorsten; Brechmann; Wolff; Schmiegel; Volkmar; Nicolas; Markus; Reiser

    2010-01-01

    Gastrointestinal bleeding from small-bowel varices is a rare and difficult to treat complication of portal hypertension. We describe the case of a 79-year-old female patient with recurrent severe hemorrhage from smallbowel varices 30 years after a complicated cholecystectomy. When double balloon enteroscopy was unsuccessful to reach the site of bleeding, a rendezvous approach was favored with intraoperative endoscopy. Active bleeding from varices within a biliodigestive anastomosis was found and controlled ...

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

    Directory of Open Access Journals (Sweden)

    Gloria Inés Beltran

    2014-07-01

    Full Text Available 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 properly map pavement response field measurements. Previous investigations have demonstrated the exceptional ability of ANNs in layer moduli estimation from non-destructive deflection tests, but most of the reported cases were developed using synthetic deflection data or hypothetical pavement systems. This paper presents further attempts to back-calculate layer moduli via ANN modeling, using a database gathered from field tests performed on three- and four-layer pavement systems. Traditional layer structuring and pavements with a stabilized subbase were considered. A three-stage methodology is developed in this study to design and validate an “optimum” ANN-based model, i.e., the best architecture possible along with adequate learning rules. An assessment of the resulting ANN model demonstrates its forecasting capabilities and efficiency in solving a complex parameter identification problem concerning pavements.

  3. Solar-reflective coating as a cooling overlay for asphalt pavement

    Science.gov (United States)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2012-04-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  4. Analytical prediction and field validation of transient temperature field in asphalt pavements

    Institute of Scientific and Technical Information of China (English)

    陈嘉祺; 李亮; 汪浩

    2015-01-01

    This work presented the development and validation of an analytical method to predict the transient temperature field in the asphalt pavement. The governing equation for heat transfer was based on heat conduction radiation and convection. An innovative time-dependent function was proposed to predict the pavement surface temperature with solar radiation and air temperature using dimensional analysis in order to simplify the complex heat exchange on the pavement surface. The parameters for the time-dependent pavement surface temperature function were obtained through the regression analysis of field measurement data. Assuming that the initial pavement temperature distribution was linear and the influence of the base course materials on the temperature of the upper asphalt layers was negligible, a close-form analytical solution of the temperature in asphalt layers was derived using Green’s function. Finally, two numerical examples were presented to validate the model solutions with field temperature measurements. Analysis results show that the solution accuracy is in agreement with field data and the relative errors at a shallower depth are greater than those at a deeper one. Although the model is not sensitive to dramatic changes in climatic factors near the pavement surface, it is applicable for predicting pavement temperature field in cloudless days.

  5. Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China.

    Science.gov (United States)

    Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

    2016-03-22

    In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase.

  6. Sustainable Development Factors in Pavement Life-Cycle: Highway/Airport Review

    Directory of Open Access Journals (Sweden)

    Peyman Babashamsi

    2016-03-01

    Full Text Available Sustainability has gained as much importance as management in business. Sustainable pavement development as a business practice should involve making evaluations according to the triple bottom line in the pavement life-cycle. Despite the current approaches to evaluating the social as well as economic and environmental feasibility of pavement projects (involving highway and airport infrastructure, there has recently been a lack of consensus on a methodology to guarantee sustainability upon assessment and analysis during the pavement life-cycle. As sustainability is a complex issue, this study intends to further explore sustainability and elaborate on its meaning. The second step involves a general depiction of the major sustainability appraisal tools, namely cost-benefit analysis, life-cycle cost analysis, life-cycle assessment, multi-criteria decision-making, environmental impact assessment and social life-cycle assessment, and an explanation of their cons and pros. Subsequently, the article addresses the application of an organized methodology to highlight the main factors or concepts that should be applied in sustainable pavement development and, more specifically, in sustainable pavement management. In the final step, research recommendations toward sustainability are given. This study is aimed to assist decision-makers in pavement management to plan sustainability frameworks in accordance with probable boundaries and restrictions.

  7. Determination of allowable subgrade frost heave with the pavement roughness index in numerical analysis

    Institute of Scientific and Technical Information of China (English)

    HongYan Ma; Feng Zhang; DeCheng Feng; Bo Lin

    2015-01-01

    Frost heave is an upward swelling of soil during cryogenic conditions in cold regions. It is caused by the accumulation of ice crystals in subgrade soil, which grow upwards when freezing temperatures penetrate into the subgrade. This study establishes the allowable soil subgrade frost heave based on the roughness standard of asphalt pavement in China, and aims to balance the pavement design and frost heave resistance of subgrades in cold regions. We formulated a mechanical model of pavement supported by the boundary conditions of differential frost heave, based on the elastic layered system theory. The differential soil subgrade frost heave was modeled as a sinusoidal function, and the allowable frost heave and the roughness index were modeled as the displacement boundaries for the top and bottom of the pavement structure. Then the allowable frost heave was back-calculated according to the roughness standard. Numerical results show that the allowable frost heave depends on the pavement structure, material properties, the highway grade, and other factors. In order to ensure that the actual soil subgrade frost heave is lower than the allowable frost heave, pavement structures and materials need to be selected and designed carefully. The numerical method proposed here can be applied to establish the frost heave re-sistance of subgrade when the pavement structure and materials are determined.

  8. An Optimization Model for Design of Asphalt Pavements Based on IHAP Code Number 234

    Directory of Open Access Journals (Sweden)

    Ali Reza Ghanizadeh

    2016-01-01

    Full Text Available Pavement construction is one of the most costly parts of transportation infrastructures. Incommensurate design and construction of pavements, in addition to the loss of the initial investment, would impose indirect costs to the road users and reduce road safety. This paper aims to propose an optimization model to determine the optimal configuration as well as the optimum thickness of different pavement layers based on the Iran Highway Asphalt Paving Code Number 234 (IHAP Code 234. After developing the optimization model, the optimum thickness of pavement layers for secondary rural roads, major rural roads, and freeways was determined based on the recommended prices in “Basic Price List for Road, Runway and Railway” of Iran in 2015 and several charts were developed to determine the optimum thickness of pavement layers including asphalt concrete, granular base, and granular subbase with respect to road classification, design traffic, and resilient modulus of subgrade. Design charts confirm that in the current situation (material prices in 2015, application of asphalt treated layer in pavement structure is not cost effective. Also it was shown that, with increasing the strength of subgrade soil, the subbase layer may be removed from the optimum structure of pavement.

  9. Greenhouse Gas Emissions from Asphalt Pavement Construction: A Case Study in China.

    Science.gov (United States)

    Ma, Feng; Sha, Aimin; Lin, Ruiyu; Huang, Yue; Wang, Chao

    2016-03-01

    In China, the construction of asphalt pavement has a significant impact on the environment, and energy use and greenhouse gas (GHG) emissions from asphalt pavement construction have been receiving increasing attention in recent years. At present, there is no universal criterion for the evaluation of GHG emissions in asphalt pavement construction. This paper proposes to define the system boundaries for GHG emissions from asphalt pavement by using a process-based life cycle assessment method. A method for evaluating GHG emissions from asphalt pavement construction is suggested. The paper reports a case study of GHG emissions from a typical asphalt pavement construction project in China. The results show that the greenhouse gas emissions from the mixture mixing phase are the highest, and account for about 54% of the total amount. The second highest GHG emission phase is the production of raw materials. For GHG emissions of cement stabilized base/subbase, the production of raw materials emits the most, about 98%. The GHG emission for cement production alone is about 92%. The results indicate that any measures to reduce GHG emissions from asphalt pavement construction should be focused on the raw materials manufacturing stage. If the raw materials production phase is excluded, the measures to reduce GHG emissions should be aimed at the mixture mixing phase. PMID:27011196

  10. Investigation of the Permanent Deformation Characteristics of Overlaid Pavement Incorporating Stress Absorbing Membrane Interlayers

    Institute of Scientific and Technical Information of China (English)

    Olumide Moses Ogundipe[1; Nicholas H. Thom[2; Andrew C. Collop[3

    2014-01-01

    This study was carried out to evaluate the resistance of overlaid pavement incorporating stress absorbing membrane interlayers to permanent deformation. In this study, the permanent deformation of the interlayer mixtures was determined using the RLAT (repeated load axial text) carried out in the Nottingham Asphalt Tester. Also, a test pavement was constructed in the laboratory to assess the resistance to permanent deformation of overlaid pavement incorporating SAMIs (stress absorbing membrane interlayers). The test pavement was divided into two along the centre line. Each of the divisions has three sections--two having SAMIs and one without SAMIs. The pavement was instrumented and trafficked. Trafficking was stopped when the pavement was deemed to have failed. The results showed that the measured permanent deformation values of the control sections were less than the sections having SAMIs. The increased permanent deformation values indicate that the introduction of SAMIs causes more vertical/horizontal deformation of the pavement. It was also found that the permanent deformation values varied depending on the composition and thickness of the SAMIs.

  11. Effectiveness of pavement-solar energy system – An experimental study

    International Nuclear Information System (INIS)

    Highlights: • We built a small-scale pilot project of pavement-solar energy utilization. • Design an automatic monitoring system to record the operating data. • The average heat absorptivity of pavement-solar energy is 37%. • The average thermal storage effectiveness of the system is 17%. - Abstract: A small-scale pilot project was built for the pavement-solar energy utilization in this paper. An automatic data acquisition system was designed to measure the effectiveness of the pavement solar energy system based on the operation data of 24 h a day in both summer and winter. Through 69 days (1656 h) of operation in summer, 2821 kW h of heat energy were stored in soil underground. In the transitional season, 4598 kW h of heat energy were taken out from soil during 104 days (2496 h) of operation in winter. The analysis showed that in summer, solar heat collection of asphalt pavement could effectively reduce 7 °C of its temperature. Under conditions of natural radiation, the average heat absorptivity of pavement was 37% and the average thermal storage effectiveness of the system was 17%. The electrical energy consumed by the system is only 11% of stored heat. During the winter, the asphalt pavement absorbs heat from underground soil which effectively increases its temperature, cutting 32% days of surface temperature below the freezing point. This not only save the energy for ice/snow removal but also mitigate associated safety risks

  12. Risk factors for bleeding after endoscopic mucosal resection

    Institute of Scientific and Technical Information of China (English)

    Masatsugu Shiba; Toshio Watanabe; Kazunari Tominaga; Yoshihiro Fujiwara; Tomoshige Hayashi; Kei Tsumura; Tetsuo Arakawa; Kazuhide Higuchi; Kaori Kadouchi; Ai Montani; Kazuki Yamamori; Hirotoshi Okazaki; Makiko Taguchi; Tomoko Wada; Atsushi Itani

    2005-01-01

    AIM: To clarify the risk factors for bleeding after endoscopic mucosal resection (EMR).METHODS: A total of 297 consecutive patients who underwent EMR were enrolled. Some of the patients had multiple lesions. Bleeding requiring endoscopic treatment was defined as bleeding after EMR. Odds ratios (OR) with 95% confidence intervals (CI), calculated by logistic regression with multivariate adjustments for covariates,were the measures of association.RESULTS: Of the 297 patients, 57 (19.2%) patients with bleeding after EMR were confirmed. With multivariate adjustment, the cutting method of ENR, diameter, and endoscopic pattern of the tumor were associated with the risk of bleeding after ENR. The multivariate-adjusted OR for bleeding after EMR using endoscopic aspiration mucosectomy was 3.07 (95%CI, 1.59-5.92) compared with strip biopsy. The multiple-adjusted OR for bleeding after EMR for the highest quartile (16-50 mm) of tumor diameter was 5.63 (95%CI, 1.84-17.23) compared with that for the lowest (4-7 mm). The multiple-adjusted OR for bleeding after EM R for depressed type of tumor was 4.21 (95%CI, 1.75-10.10) compared with elevated type.CONCLUSION: It is important to take tumor characteristics (tumor size and endoscopic pattern) and cutting method of EMR into consideration in predicting bleeding after ENR.

  13. Incidence and Management of Bleeding Complications Following Percutaneous Radiologic Gastrostomy

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Nieun; Shin, Ji Hoon; Ko, Gi Young; Yoon, Hyun Ki; Gwon, Dong Il; Kim, Jin Hyoung; Sung, Kyu Bo [Asan Medical Center, Ulsan University College of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    Upper gastrointestinal (GI) bleeding is a serious complication that sometimes occurs after percutaneous radiologic gastrostomy (PRG). We evaluated the incidence of bleeding complications after a PRG and its management including transcatheter arterial embolization (TAE). We retrospectively reviewed 574 patients who underwent PRG in our institution between 2000 and 2010. Eight patients (1.4%) had symptoms or signs of upper GI bleeding after PRG. The initial presentation was hematemesis (n = 3), melena (n = 2), hematochezia (n = 2) and bloody drainage through the gastrostomy tube (n = 1). The time interval between PRG placement and detection of bleeding ranged from immediately after to 3 days later (mean: 28 hours). The mean decrease in hemoglobin concentration was 3.69 g/dL (range, 0.9 to 6.8 g/dL). In three patients, bleeding was controlled by transfusion (n = 2) or compression of the gastrostomy site (n = 1). The remaining five patients underwent an angiography because bleeding could not be controlled by transfusion only. In one patient, the bleeding focus was not evident on angiography or endoscopy, and wedge resection including the tube insertion site was performed for hemostasis. The other four patients underwent prophylactic (n = 1) or therapeutic (n = 3) TAEs. In three patients, successful hemostasis was achieved by TAE, whereas the remaining one patient underwent exploration due to persistent bleeding despite TAE. We observed an incidence of upper GI bleeding complicating the PRG of 1.4%. TAE following conservative management appears to be safe and effective for hemostasis.

  14. Recent Update of Embolization of Upper Gastrointestinal Tract Bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ji Hoon [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2012-02-15

    Nonvariceal upper gastrointestinal (UGI) bleeding is a frequent complication with significant morbidity and mortality. Although endoscopic hemostasis remains the initial treatment modality, severe bleeding despite endoscopic management occurs in 5-10% of patients, necessitating surgery or interventional embolotherapy. Endovascular embolotherapy is now considered the first-line therapy for massive UGI bleeding that is refractory to endoscopic management. Interventional radiologists need to be familiar with the choice of embolic materials, technical aspects of embolotherapy, and the factors affecting the favorable or unfavorable outcomes after embolotherapy for UGI bleeding.

  15. Transcatheter arterial embolization in gastric cancer patients with acute bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun Joo; Shin, Ji Hoon; Yoon, Hyun-Ki; Ko, Gi-Young; Gwon, Dong-Il; Song, Ho-Young; Sung, Kyu-Bo [University of Ulsan College of Medicine, Department of Radiology and Research Institute of Radiology, Seoul (Korea)

    2009-04-15

    The safety and clinical effectiveness of transcatheter arterial embolization for bleeding associated with unresectable gastric cancer was evaluated. Twenty-three patients with bleeding from unresectable gastric cancer underwent transcatheter arterial embolization. Of the 23 patients, eight showed signs of active bleeding, such as contrast extravasation or pseudoaneurysm, seven showed only tumor staining, and the remaining eight patients showed negative angiographic findings. All embolization procedures were successful without procedure-related complications. In all eight active bleeding patients, immediate hemostasis was achieved. The overall clinical success rate was 52% (12/23). Recurrent bleeding within 1 month occurred in one (8%) in 12 patients with initial clinical success. One patient showed partial splenic infarction after embolization of the splenic artery for active bleeding from the short gastric artery. Overall 30-day mortality rate was 43% (10/23). The median overall survival period was 38 days. In patients with bleeding from unresectable gastric cancer, transcatheter arterial embolization was found to be safe and effective for achieving immediate hemostasis for active bleeding. Although the clinical success rate was not high, the recurrent bleeding rate was low at 1 month post procedure. (orig.)

  16. Angiography Diagnosis and Treatment of Traumatic Artery Bleeding

    Institute of Scientific and Technical Information of China (English)

    WANG Li; WANG Yan; LIU Jingzhang

    2002-01-01

    Objective After angiography and embolization of three cases suffering from traumatic artery bleeding we summarized the selective embolization of different artery bleeding cases and their treatment analysis. Methods The three cases were all female,among them,one suffering from hepatic artery bleeding by a traffic accident, the other two caused by iatrogenic damage. Of the two, one suffered from bleeding after the gall bladder removal, the other from bleeding after puncture biopsy through the kidney.Seldinger technique was used on the three cases, and puncture intubation was superselected and put through arterial femoralis. Catheters were put separately inside the target blood vessels to have radiography and contrast medium was found to have out flowed out to the bleeding artery. And then the mixed gelatin sponge particles were put into, Ultravist contrast medium to make suspension. Through fluoroscopy the suspension was injected into bleeding artery until no contrast medium out flowed. After that radiography was used to watch the result. Results After the embolization the three cases stopped bleeding at once with remarkable effects. Conclusion Therefore we conclude the embolization is the best method for treating artery bleeding.

  17. Permeable pavement and stormwater management systems: a review.

    Science.gov (United States)

    Imran, H M; Akib, Shatirah; Karim, Mohamed Rehan

    2013-01-01

    Uncontrolled stormwater runoff not only creates drainage problems and flash floods but also presents a considerable threat to water quality and the environment. These problems can, to a large extent, be reduced by a type of stormwater management approach employing permeable pavement systems (PPS) in urban, industrial and commercial areas, where frequent problems are caused by intense undrained stormwater. PPS could be an efficient solution for sustainable drainage systems, and control water security as well as renewable energy in certain cases. Considerable research has been conducted on the function of PPS and their improvement to ensure sustainable drainage systems and water quality. This paper presents a review of the use of permeable pavement for different purposes. The paper focuses on drainage systems and stormwater runoff quality from roads, driveways, rooftops and parking lots. PPS are very effective for stormwater management and water reuse. Moreover, geotextiles provide additional facilities to reduce the pollutants from infiltrate runoff into the ground, creating a suitable environment for the biodegradation process. Furthermore, recently, ground source heat pumps and PPS have been found to be an excellent combination for sustainable renewable energy. In addition, this study has identified several gaps in the present state of knowledge on PPS and indicates some research needs for future consideration. PMID:24527626

  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. ESTIMATION OF THE CONCRETE PAVEMENT TEMPERATURE FIELDS AND THEIR GRADIENTS

    Directory of Open Access Journals (Sweden)

    M. K. Pshembaev

    2015-01-01

    Full Text Available The heat fluxes impact on the road-dressing concrete surfacing under different regions climatic conditions of the construction and maintenance dramatically degrades their solidity, corroding-, shiftingand frost-resistance, and ultimately – the service durability. The source of deformation processes is the character of the gradient temperature fields in the road dressing materials developing with both protracted (static and short run (dynamic heat-and-mass impacts that forward destruction of the pavement surface layers being in contact with free air. In addition, pulsating hydrodynamic pressures appear in the pores of moisture-laden pavement as a result of the vehicular traffic that foster material structure disruption of the surface layers leading to irreversible deformation incipiency (cracks etc.. The authors report of developing a С++ computer program for temperature and gradient fields engineering evaluations of the road dressings made of materials with various surfacing and free-air thermophysical characteristics in line with boundary conditions of the 3rd kind for semi-bounded body. The paper presents the evaluation results in form of graphical curves of the temperature allocation along the surfacing thickness as function of its initial temperature and thermophysical characteristics of the concrete. 

  20. An Overview Of Pavement Management System For Industrial Areas

    Science.gov (United States)

    Hokam, Vivek S.

    2012-03-01

    ACT With the current surge in national economy the industrial traffic has increased many folds in terms of quantity of load and traffic volume. This results in early deterioration of the roads. Also the serviceability reduces hampering the industry's supply of raw material and transport of finished goods. An efficient road transportation system is of vitally important for smooth operations of industrial units. Construction of new roads needs an enormous investment. However, once constructed the road network system requires huge resources to maintain serviceability and to ensure safe passage at an appropriate speed and with low VOC (Vehicle Operating Cost). Road maintenance is therefore an essential function and should be carried out on a timely basis. The cost of providing and maintaining the roads for the industrial areas at an acceptable serviceability level is quite high. It is therefore essential for a transportation engineer to attempt establishing an acceptable pavement condition level from economic, safety and environmental point of view. In today's economic environment of constrained budgets, as the existing road infrastructure has aged, a more systematic approach towards determining maintenance and rehabilitation needs is necessary. The efficient pavement management system shall provide objective information and useful analysis to ensure consistent and cost effective decisions related to preservation of existing industrial road network in healthy condition.

  1. 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.

  2. The effect of aggregate density on pavement performance of SMA-13 asphalt mixture

    Directory of Open Access Journals (Sweden)

    Qiao Yinping

    2016-05-01

    Full Text Available This paper chooses the top layer SMA-13 asphalt mixture material as the research object. Basalt was selected as pavement material, and modified SBS asphalt was used as a cementing material. Two basalt aggregates with different densities were used to carry out standard Marshall test in the laboratory.Aimed at the volume parameters of the asphalt mixture carry on anaiysis,and obtian the effect of aggregate density on pavement performance of SMA-13 asphalt mixture, which is that the density of aggregate has a significant effect on the void ratio, saturation, and the gap rate of the aggregate, thus affecting the pavement performance of the asphalt mixture

  3. The Dependence of Physical Mechanical Properties of Concrete Pavement Blocks on Coarse Aggregate Type

    Directory of Open Access Journals (Sweden)

    Malaiškienė Jurgita

    2014-12-01

    Full Text Available The aim of this research is to determine the dependences of the physical mechanical properties of vibropressed concrete (pavement blocks on the type of coarse aggregate used in the main layer. Sustainability of concrete pavement blocks is a really important matter. Five different batches of pavement blocks were produced, changing the consistence ratio of coarse aggregate in the main layer. There are two types of course aggregate: crushed gravel and granite. The consistence of a facing layer was not changed. All tests: density, tensile split strength, water absorption for vibro-pressed concrete units were made according to EN 1338:2003+AC2006.

  4. 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 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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-11-21

    The objective of this study is to evaluate the life cycle costs and market barriers associated with using reflective paving materials in streets and parking lots as a way to reduce the urban heat island effect. We calculated and compared the life cycle costs of conventional asphalt concrete (AC) pavements to those of other existing pavement technologies with higher reflectivity-portland cement concrete (PCC), porous pavements, resin pavements, AC pavements using light-colored chip seals, and AC pavements using light-colored asphalt emulsion additives. We found that for streets and parking lots, PCC can provide a cost-effective alternative to conventional AC when severely damaged pavements must be completely reconstructed. We also found that rehabilitating damaged AC streets and intersections with thin overlays of PCC (ultra-thin white topping) can often provide a cost-effective alternative to standard rehabilitation techniques using conventional AC. Chip sealing is a common maintenance treatment for low-volume streets which, when applied using light-colored chips, could provide a reflective pavement surface. If the incremental cost of using light-colored chips is low, this chip sealing method could also be cost-effective, but the incremental costs of light-colored chips are as of yet uncertain and expected to vary. Porous pavements were found to have higher life cycle costs than conventional AC in parking lots, but several cost-saving features of porous pavements fell outside the boundaries of this study. Resin pavements were found to be only slightly more expensive than conventional AC, but the uncertainties in the cost and performance data were large. The use of light-colored additives in asphalt emulsion seal coats for parking lot pavements was found to be significantly more expensive than conventional AC, reflecting its current niche market of decorative applications. We also proposed two additional approaches to increasing the reflectivity of conventional AC

  6. Tranexamic acid for upper gastrointestinal bleeding

    DEFF Research Database (Denmark)

    Bennett, Cathy; Klingenberg, Sarah Louise; Langholz, Ebbe;

    2014-01-01

    Background Tranexamic acid reduces haemorrhage through its antifibrinolytic effects. In a previous version of the present review, we found that tranexamic acid may reduce mortality. This review includes updated searches and new trials.Objectives To assess the effects of tranexamic acid versus......-effect and random-effects model meta-analyses and presented results as risk ratios (RRs) with 95% confidence intervals (CIs) and used I² as a measure of between-trial heterogeneity. We analysed tranexamic acid versus placebo or no intervention and tranexamic acid versus antiulcer drugs separately. To analyse...... sources of heterogeneity and robustness of the overall results, we performed subgroup, sensitivity and sequential analyses.Main results We included eight randomised controlled trials on tranexamic acid for upper gastrointestinal bleeding. Additionally, we identified one large ongoing pragmatic randomised...

  7. Abnormal uterine bleeding: a clinicohistopathological analysis

    Directory of Open Access Journals (Sweden)

    Anupamasuresh Y

    2014-06-01

    Methods: In our prospective study of 359 Patients of the age between 46 and 73 years, clinical characteristics and the pattern of endometrial histopathology and their association in women, who present with abnormal uterine bleeding, are categorised into six groups. Results: In our study, a significant correlation of histopathology and BMI was observed with endometrial hyperplasia and malignancy in obese patient i.e. 37 out 96 and 13 out of 23 respectively. The incidence of malignancy has been increasing with the age being 1.6% in 46-50 years to 60% in 70-75 years. In our study 116 (32.3% had hypertension, 33 patients (9.2% had diabetes mellitus, 40 patients (11.1% had hypothyroidism. Conclusions: We found a maximum incidence of AUB in multiparous women. Clinicohistopathological analysis of AUB revealed endometrial hyperplasia in majority of patients. [Int J Reprod Contracept Obstet Gynecol 2014; 3(3.000: 656-661

  8. [Perioperative management and therapy of bleeding complications].

    Science.gov (United States)

    von Heymann, Christian; Kaufner, Lutz; Körber, Mareike

    2014-03-01

    The new oral anticoagulants directly inhibit either thrombin (Dabigatran, Pradaxa®,) or activated Factor X (rivaroxaban, Xarelto®, and apixaban, Eliquis®) and have been approved for thromboprophylaxis after hip and knee replacement surgery and stroke prevention in non-valvular atrial fibrillation. Moreover, rivaroxaban has been approved for the treatment of deep venous thrombosis, prevention of pulmonary embolism and anticoagulation after acute myocardial infarction. The direct FXa-inhibitor edoxaban (Lixiana®) expects approval for the prevention of stroke in atrial fibrillation in Germany in 2014. The half lives of all direct anticoagulants range between 8 and 17 hours. Dabigatran (Pradaxa®) and rivaroxaban (Xarelto®) are mainly excreted by the kidneys, apixaban (Eliquis®) by the liver (75%) and edoxaban (Lixiana®) by the kidneys (40%) and the faeces in 60%. Prior to surgery a shorter cessation is expected compared to the vitamin k antagonists phenprocoumon (Marcumar®, Falithrom®) and warfarin (Coumadin®). For acute bleedings caused by the direct thrombin inhibitor dabigatran (Pradaxa®) hemodialysis is recommended to eliminate the drug from the plasma. Due to the high protein binding the direkt FXa-inhibitors rivaroxaban (Xarelto®) and apixaban (Eliquis®) can not be hemodialysed. For edoxaban (Lixiana®) no data on elimination by renal replacement therapy are available. In case of life-threatening bleeding the replacement of a prothrombin complex preparation (PCC) containing the factors II, VII, IX and X and, second line, activated factor concentrates as recombinant factor VIIa or activated prothrombin complex preparations are recommended. PMID:24711240

  9. Platelet Function Tests in Bleeding Disorders.

    Science.gov (United States)

    Lassila, Riitta

    2016-04-01

    Functional disorders of platelets can involve any aspect of platelet physiology, with many different effects or outcomes. These include platelet numbers (thrombocytosis or thrombocytopenia); changes in platelet production or destruction, or capture to the liver (Ashwell receptor); altered adhesion to vascular injury sites and/or influence on hemostasis and wound healing; and altered activation or receptor functions, shape change, spreading and release reactions, procoagulant and antifibrinolytic activity. Procoagulant membrane alterations, and generation of thrombin and fibrin, also affect platelet aggregation. The above parameters can all be studied, but standardization and quality control of assay methods have been limited despite several efforts. Only after a comprehensive clinical bleeding assessment, including family history, information on drug use affecting platelets, and exclusion of coagulation factor, and tissue deficits, should platelet function testing be undertaken to confirm an abnormality. Current diagnostic tools include blood cell counts, platelet characteristics according to the cell counter parameters, peripheral blood smear, exclusion of pseudothrombocytopenia, whole blood aggregometry (WBA) or light transmission aggregometry (LTA) in platelet-rich plasma, luminescence, platelet function analysis (PFA-100) for platelet adhesion and deposition to collagen cartridges under blood flow, and finally transmission electron microscopy to exclude rare structural defects leading to functional deficits. The most validated test panels are included in WBA, LTA, and PFA. Because platelets are isolated from their natural environment, many simplifications occur, as circulating blood and interaction with vascular wall are omitted in these assays. The target to reach a highly specific platelet disorder diagnosis in routine clinical management can be exhaustive, unless needed for genetic counseling. The elective overall assessment of platelet function disorder

  10. Impact of inherited bleeding disorders on pregnancy and postpartum hemorrhage.

    Science.gov (United States)

    Shahbazi, Shirin; Moghaddam-Banaem, Lida; Ekhtesari, Fatemeh; Ala, Fereydoun A

    2012-10-01

    Inherited bleeding disorders are caused by various genetic defects in the proteins involved in haemostasis. Female patients or carriers are faced with the risk of haemorrhage throughout life. During pregnancy and postpartum, this complication affects the health of either the mother or the baby, or both. This retrospective cohort study was designed to assess the occurrence of obstetric bleeding in the three trimesters of pregnancy, along with primary and secondary postpartum haemorrhage among 100 women with inherited bleeding disorders. A questionnaire was designed in order to collect historical data. The patients were evaluated in three groups: haemophilia carriers, von Willebrand disease (VWD) and rare bleeding disorders. In comparison with normal women, significantly severe bleeding was observed among patients in all of the five stages. VWD patients showed a higher frequency of bleeding in first trimester but the rate of miscarriage was lower. Haemophilia carriers were threatened with bleeding complications during the prenatal period, but they also had the highest frequency of postpartum haemorrhage. Based on our results, vaginal bleeding is a serious threat in all three patient groups, especially during the first trimester of pregnancy and in the postpartum period. PMID:22821002

  11. The role of nuclear medicine in acute gastrointestinal bleeding

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, P. (Saint James' s Hospital, Leeds (United Kingdom). Dept. of Radiology)

    1993-10-01

    In most patients with upper gastrointestinal (GI) bleeding, endoscopy will locate the site and cause of bleeding, and also provide an opportunity for local therapy. The cause of lower GI bleeding is often difficult to attribute, even when pathology is found by colonoscopy or barium enema. Nuclear medicine techniques can be used to identify the site of bleeding in those patients in whom the initial diagnostic procedures are negative or inconclusive. Methods using transient labelling of blood (e.g. [sup 99]Tc[sup m]-sulphur colloid) produce a high target-to-background ratio in positive cases, give quick results and localize bleeding sites accurately, but depend upon bleeding being active at the time of injection. Techniques using stable blood labelling (e.g. [sup 99]Tc[sup m]-labelled red blood cells) may be positive even with intermittent bleeding but may take several hours to produce a result and are less precise in localization. The most useful application is in patients with recurrent or prolonged bleeding, those with inconclusive endoscopy or barium studies, and those who are high-risk surgical candidates. (author).

  12. Role of endoscopy in the management of acute diverticular bleeding

    Institute of Scientific and Technical Information of China (English)

    Charalampos Pilichos; Emmanouil Bobotis

    2008-01-01

    Colonic diverticulosis is one of the most common causes of lower gastrointestinal bleeding. Endoscopy is not only a useful diagnostic tool for localizing the bleeding site, but also a therapeutic modality for its management. To date, haemostatic methods have included adrenaline injection, mechanical clipping, thermal and electrical coagulation or combinations of them. The results of all published data are herein reviewed.

  13. 14 CFR 33.66 - Bleed air system.

    Science.gov (United States)

    2010-01-01

    ... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES Design and Construction; Turbine Aircraft Engines § 33.66 Bleed air system. The engine must supply bleed air without adverse effect on the engine, excluding reduced thrust or...

  14. Gastrointestinal bleeding in patients with hereditary hemorrhagic telangiectasia

    DEFF Research Database (Denmark)

    Kjeldsen, A D; Kjeldsen, J

    2000-01-01

    Gastrointestinal bleeding occurs in a number of patients with hereditary hemorrhagic telangiectasia (HHT) and may lead to a high transfusion need. The aim of this study was to estimate the occurrence and severity of gastrointestinal bleeding in a geographically well defined HHT population....

  15. Management of bleeding complications in patients with cancer on DOACs.

    Science.gov (United States)

    Schulman, Sam; Shrum, Jeffrey; Majeed, Ammar

    2016-04-01

    There has been a concern that major bleeding events (MBE) on direct-acting oral anticoagulants (DOACs) will be more difficult to manage than on vitamin K antagonists. Patients with cancer and DOAC-associated bleeding may be even more of a challenge to manage. We therefore reviewed the literature on bleeding in patients with cancer on DOACs. In addition, we performed an analysis of individual patient data from 5 phase III trials on treatment with dabigatran with focus on those with cancer. In 6 randomized trials the risk of MBE in patients with cancer was similar on treatment with DOACs compared to vitamin K antagonists. Bleeding was in the majority of patients managed with supportive therapy alone. In the individual patient data analysis there were no significant differences in use of hemostatic products, transfusion of red cells, effectiveness of management, bleeding-related mortality or 30-day all-cause mortality between patients with cancer treated with dabigatran or with warfarin. Local hemostatic therapy, including resection of the cancer site was more common in patients with gastrointestinal bleeding with cancer than among those without cancer. We conclude that management of bleeding in patients with cancer and on a DOAC does not pose a greater challenge than management of bleeding in patients without cancer. PMID:27067968

  16. The Mechanisms of Abnormal Bleeding in Patients with Anovulatory Dysfunctional Uterine Bleeding

    Institute of Scientific and Technical Information of China (English)

    Lu LUO; Feng-chuan ZHU; Yao-ying ZENG

    2002-01-01

    Objective To investigate the mechanisms of abnormal bleeding in patients with anovulatory dysfunctional uterine bleeding (DUB) and to analyze the correlation between vascular endothelial growth factor (VEGF) and microvessel density in the endometrium Materials & Methods Immunohistochemistry was used to study the expression of VEGF protein in the proliferative and hyperplastic endometrium. CD34 ,a marker of microvessel, was selected to measure microvessel density (MVD) in the endometrium.Fifteen women who were found to have no condition with normal menstrual cycles were set as control group.Results VEGF immunoreactivity in glandular epithelia cells was significantly lower in the hyperplastic endometrium than that of controls(P < 0. 05). There was no significant difference in VEGF protein level between proliferative DUB endometrium and that of controls. A positive correlation was found between glandular VEGF and MVD in the endometrium(r=0. 666, P<0.05). Conclusion The anovulatory DUB is associated with down-regulation of VEGF in the endometrium, and decreased secretion of VEGF will result in the disruption of angiogenesis, as a clinical manifestation of irregular bleeding.

  17. Comparative effectiveness of flossing and brushing in reducing interproximal bleeding.

    Science.gov (United States)

    Graves, R C; Disney, J A; Stamm, J W

    1989-05-01

    This study assesses the comparative effectiveness of three types of dental floss and toothbrushing in reducing interproximal bleeding sites, measured by stimulation with wooden interdental cleaners using the interdental bleeding index assessment method. The 119 adult subjects with gingival inflammation were randomly assigned to one of four groups at the beginning of a supervised 2 week clinical trial. The toothbrushing only group achieved a 35% reduction in bleeding sites and the three flossing groups all demonstrated dramatic reductions of about 67%. The three varieties of dental flosses were about equally effective in reducing interproximal bleeding and doubly effective as toothbrushing alone. Compared to probing, the interdental bleeding index method is considered a simplified method of assessing interproximal gingival inflammation.

  18. Scintigraphic detection of gastrointestinal bleeding: a review of current methods

    International Nuclear Information System (INIS)

    Recent experience with radionuclide imaging has provided the clinician with several techniques to noninvasively detect and locate sources of gastrointestinal hemorrhage. These tests can be rapidly performed and often in an ICU setting. One method used Tc-99m sulfur colloid which, in an animal model, has been shown to detect acute bleeding at rates as low as 0.1 ml/min. However, because the tracer remains in the blood for a short period of time, it may be suboptimal for identifying patients with intermittent bleeding. Tc-99m red cells is a tracer that remains within the blood and permits detection of both acute and intermittent bleeding. With tagged red cells, sites of bleeding from both the upper and lower gastrointestinal tract can be found. Both of these techniques can provide important information in the patient with suspected active gastrointestinal bleeding and aid the clinician in more effective management including the use of invasive diagnostic and therapeutic techniques

  19. New insights to occult gastrointestinal bleeding: From pathophysiology to therapeutics

    Institute of Scientific and Technical Information of China (English)

    Antonio; Damián; Sánchez-Capilla; Paloma; De; La; Torre-Rubio; Eduardo; Redondo-Cerezo

    2014-01-01

    Obscure gastrointestinal bleeding is still a clinical challenge for gastroenterologists. The recent development of novel technologies for the diagnosis and treatment of different bleeding causes has allowed a better management of patients, but it also determines the need of a deeper comprehension of pathophysiology and the analysis of local expertise in order to develop a rational management algorithm. Obscure gastrointestinal bleeding can be divided in occult, when a positive occult blood fecal test is the main manifestation, and overt, when external sings of bleeding are visible. In this paper we are going to focus on overt gastrointestinal bleeding, describing the physiopathology of the most usual causes, analyzing the diagnostic procedures available, from the most classical to the novel ones, and establishing a standard algorithm which can be adapted depending on the local expertise or availability. Finally, we will review the main therapeutic options for this complex and not so uncommon clinical problem.

  20. Alternative Treatment for Bleeding Peristomal Varices: Percutaneous Parastomal Embolization

    Energy Technology Data Exchange (ETDEWEB)

    Pabon-Ramos, Waleska M., E-mail: waly.pr@duke.edu [Duke University Hospital, Department of Radiology (United States); Niemeyer, Matthew M. [Washington University Medical Center, Mallinckrodt Institute of Radiology (United States); Dasika, Narasimham L., E-mail: narasimh@med.umich.edu [University of Michigan Health System, Department of Radiology (United States)

    2013-10-15

    Purpose: To describe how peristomal varices can be successfully embolized via a percutaneous parastomal approach. Methods: The medical records of patients who underwent this procedure between December 1, 2000, and May 31, 2008, were retrospectively reviewed. Procedural details were recorded. Median fluoroscopy time and bleeding-free interval were calculated. Results: Seven patients underwent eight parastomal embolizations. The technical success rate was 88 % (one failure). All embolizations were performed with coils combined with a sclerosant, another embolizing agent, or both. Of the seven successful parastomal embolizations, there were three cases of recurrent bleeding; the median time to rebleeding was 45 days (range 26-313 days). The remaining four patients did not develop recurrent bleeding during the follow-up period; their median bleeding-free interval was 131 days (range 40-659 days). Conclusion: This case review demonstrated that percutaneous parastomal embolization is a feasible technique to treat bleeding peristomal varices.

  1. 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)

  2. TPF 5(063) "Improving the Quality of Pavement Profile Measurement" Update

    OpenAIRE

    Mikhail, Magdy

    2014-01-01

    Functional Session 1: Longitudinal Profile Moderated by Magdy Mikhail This presentation was held at the Pavement Evaluation 2014 Conference, which took place from September 15-18, 2014 in Blacksburg, Virginia. Presentation only

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

    Science.gov (United States)

    Xiang, H. J.; Wang, J. J.; Shi, Z. F.; Zhang, Z. W.

    2013-09-01

    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.

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

    Science.gov (United States)

    Han, Baoguo; Zhang, Kun; Burnham, Tom; Kwon, Eil; Yu, Xun

    2013-01-01

    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.

  5. 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%.

  6. Evaluation and verification of two systems for mechanistic structural design of asphalt concrete pavements in Nebraska

    Science.gov (United States)

    Sneddon, R. V.

    1982-07-01

    The VESY-3-A mechanistic design system for asphalt pavements was field verified for three pavement sections at two test sites in Nebraska. PSI predictions from VESYS were in good agreement with field measurements for a 20 year old 3 layer pavement located near Elmwood, Nebraska. Field measured PSI values for an 8 in. full depth pavement also agreed with VESYS predictions for the study period. Rut depth estimates from the model were small and were in general agreement with field measurements. Cracking estimates were poor and tended to underestimate the time required to develop observable fatigue cracking in the field. Asphalt, base course and subgrade materials were tested in a 4.0 in. diameter modified triaxial cell. Test procedures used dynamic conditioning and rest periods to simulate service conditions.

  7. 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.

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

    Science.gov (United States)

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

  9. 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...

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

    Science.gov (United States)

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

  11. Techniques to Determine Maintenace Frequency of Permeable Pavement Systems with Time Domain Reflectometers (TDRs

    Science.gov (United States)

    As the surface clogs in permeable pavement systems, they lose effectiveness and require maintenance. There is limited direct guidance for determining when maintenance is needed to prevent surface runoff bypass. Research is being conducted using multiple time domain reflectomete...

  12. Microsurfacing – An Eco-Efficient Tool for Road Safety and Pavement Maintenance

    Directory of Open Access Journals (Sweden)

    Rajesh S. Gujar

    2013-11-01

    Full Text Available With the development of infrastructure, in rapidly developing modern era, frequent maintenance of existing infrastructure, especially roads is of prime importance.  Microsurfacing is a preventive maintenance technique (preventative maintenance strategy aims at producing the most cost-effective improvements in pavement quality and life involving three to six millimeter sized bitumen aggregate treated with a special emulsion.  The layer is neatly laid down on road section requiring maintenance.  This paper aims at focusing on the contributions made by researchers on Microsurfacing as a tool for pavement maintenance and repair.  Although the technique is finding its place in Indian sub-continents little late, but nevertheless it is universally considered as an inevitable tool as far as preventive pavement maintenance is concerned and should be used to extend life of the underlying pavement

  13. 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.

  14. Contributions of performance-graded asphalt to low temperature cracking resistance of pavements. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Loh, S.W.; Olek, J.

    1999-05-01

    The purpose of this research was to study and evaluate the role that asphalt cracking. As part of the Strategic Highway Research Program (SHRP) new specifications for asphalt binders were developed that are based on the performance of the material. The asphalt binder graded and specified according to these new performance-based specifications is called PG binder. These new specifications are commonly referred to as Superpave (Superior Performing Asphalt Pavement) binder specifications. A section of Interstate 64 in southern Indiana was experiencing severe low temperature cracking before it was reconstructed over the summers of 1995 and 1996. The binder used in the new pavement mixes was PG material. Dynamic Shear Rheometer (DSR) tests, Bending Beam Rheometer (BBR) tests, and viscosity tests were performed on this binder. Comparisons were made between test results obtained from the binders in the old pavement and the new pavement. All tests and comparisons were based on the Superpave binder specifications.

  15. Investigating In Situ Properties of Recycled Asphalt Pavement with Foamed Asphalt as Base Stabilizer

    Directory of Open Access Journals (Sweden)

    Christina Plati

    2010-01-01

    Full Text Available The objective of the present study was to conduct a comprehensive field experiment for the in situ assessment of in-depth recycled asphalt pavement using foamed asphalt as a stabilization treatment for base works. For this purpose Nondestructive Testing (NDT data collected using the Falling Weight Deflectometer (FWD and Ground Penetrating Radar (GPR along a foamed asphalt recycled pavement section was thoroughly analysed. Critical issues including the stabilized material curing and the contribution of the asphalt layers to the structural properties of the in-depth recycled pavement are discussed. In addition, recommendations concerning the improvement of the structural condition of the in-depth recycled pavement are developed based on this practical approach of investigation using NDT.

  16. Mechanical Behavior and Failure Mechanism of Recycled Semi-lfexible Pavement Material

    Institute of Scientific and Technical Information of China (English)

    DING Qingjun; ZHAO Mingyu; SHEN Fan; ZHANG Xiaoqiang

    2015-01-01

    The mechanical behavior and failure mechanism of recycled semi-lfexible pavement material were investigated by different scales method. The macroscopic mechanical behavior of samples was studied by static and dynamic splitting tensile tests on mechanics testing system (MTS). The mechanical analysis in micro scale was carried out by material image analysis method and ifnite element analysis system. The strains of recycled semi-lfexible pavement material on samples surface and in each phase materials were obtained. The test results reveal that the performance of recovered asphalt binder was the major determinant on the structural stability of recycled semi-lfexible pavement material. The asphalt binder with high viscoelasticity could delay the initial cracking time and reduce the residual strain under cyclic loading conditions. The failure possibility order of each phase in recycled semi-flexible pavement material was asphalt binder, reclaimed aggregate, cement paste and virgin aggregate.

  17. Desert Pavement Process and Form: Modes and Scales of Landscape Stability and Instability in Arid Regions

    Science.gov (United States)

    Wells, Stephen G.; McFadden, Leslie D.; McDonald, Eric V.; Eppes, Martha C.; Young, Michael H.; Wood, Yvonne A.

    2014-05-01

    Desert pavements are recognized in arid landscapes around the world, developing via diminution of constructional/depositional landform relief and creating a 1-2 stone thick armor over a "stone free" layer. Surface exposure dating demonstrates that clasts forming the desert pavements are maintained at the land surface over hundreds of thousands of years, as aeolian fines are deposited on the land surface, transported into the underlying parent material and incorporated into accretionary soil horizons (e.g., the stone free or vesicular [Av] horizon). This surface armor provides long-term stability over extensive regions of the landscape. Over shorter time periods and at the landform-element scale, dynamic surficial processes (i.e., weathering, runoff) continue to modify the pavement form. Clast size reduction in comparison to underlying parent material, along with armoring and packing of clasts in pavements contribute to their persistence, and studies of crack orientations in pavement clasts indicate physical weathering and diminution of particle size are driven by diurnal solar insolation. Over geologic time, cracks form and propagate from tensile stresses related to temporal and spatial gradients in temperature that evolve and rotate in alignment with the sun's rays. Observed multimodal nature of crack orientations appear related to seasonally varying, latitude-dependent temperature fields resulting from solar angle and weather conditions. Surface properties and their underlying soil profiles vary across pavement surfaces, forming a landscape mosaic and controlling surface hydrology, ecosystem function and the ultimate life-cycle of arid landscapes. In areas of well-developed pavements, surface infiltration and soluble salt concentrations indicate that saturated hydraulic conductivity of Av horizons decline on progressively older alluvial fan surfaces. Field observations and measurements from well-developed desert pavement surfaces landforms also yield

  18. Bleeding disorders in the tribe: result of consanguineous in breeding

    Directory of Open Access Journals (Sweden)

    Borhany Munira

    2010-09-01

    Full Text Available Abstract Objective To determine the frequency and clinical features of bleeding disorders in the tribe as a result of consanguineous marriages. Design Cross Sectional Study Introduction Countries in which consanguinity is a normal practice, these rare autosomal recessive disorders run in close families and tribes. Here we describe a family, living in village Ali Murad Chandio, District Badin, labeled as haemophilia. Patients & Methods Our team visited the village & developed the pedigree of the whole extended family, up to seven generations. Performa was filled by incorporating patients, family history of bleeding, signs & symptoms, and bleeding from any site. From them 144 individuals were screened with CBC, bleeding time, platelet aggregation studies & RiCoF. While for PT, APTT, VWF assay and Factor VIII assay, samples were kept frozen at -70 degrees C until tested. Results The family tree of the seven generations comprises of 533 individuals, 63 subjects died over a period of 20 years and 470 were alive. Out of all those 144 subjects were selected on the basis of the bleeding history. Among them 98(68.1% were diagnosed to have a bleeding disorder; 44.9% patients were male and 55.1% patients were female. Median age of all the patients was 20.81, range (4 months- 80 yrs. The results of bleeding have shown that majority had gum bleeding, epistaxis and menorrhagia. Most common bleeding disorder was Von Willebrand disease and Platelet functional disorders. Conclusion Consanguineous marriages keep all the beneficial and adversely affecting recessive genes within the family; in homozygous states. These genes express themselves and result in life threatening diseases. Awareness, education & genetic counseling will be needed to prevent the spread of such common occurrence of these bleeding disorders in the community.

  19. Genotypes of Helicobacter pylori in patients with peptic ulcer bleeding

    Institute of Scientific and Technical Information of China (English)

    Chin-Lin Perng; Hwai-Jeng Lin; Wen-Ching Lo; Guan-Ying Tseng; I-Chen Sun; Yueh-Hsing Ou

    2004-01-01

    AIM: Helicobacter pyloricauses chronic gastritis, peptic ulcer,gastric cancer and MALT-lymphoma. Different genotypes of Helicobacter pylori are confirmed from diverse geographic areas. Its association with bleeding peptic ulcer remains controversial. The aim of this study was to investigate the Helicobacter pylori vac4 alleles, cagA and iceA in patients with bleeding peptic ulcer.METHODS: We enrolled patients with bleeding, nonbleeding peptic ulcers and chronic gastritis. Biopsy specimens were obtained from the antrum of the stomach for rapid urease test, bacterial culture and PCR assay. DNA extraction and polymerase chain reaction were used to detect the presence or absence of cagA and to assess the polymorphism of vac4 and iceA.RESULTS: A total of 168 patients (60.4%) (25 patients with chronic gastritis, 26 patients with bleeding gastric ulcer,51 patients with non-bleeding gastric ulcer, 26 patients with bleeding duodenal ulcer, and 40 patients with non-bleeding duodenal ulcer) were found to have positive PCR results between January 2001 and December 2002. Concerning genotypes, we found cagA (139/278, 50%), vacA s1a (127/278, 45.7%), and iceA1 (125/278, 45%) predominated in all studied patients. In patients with bleeding peptic ulcers,vac4 s1a and m1T were fewer than those in patients with non-bleeding peptic ulcers (37/106 vs69/135, P=0.017, and 4/106 vs21/135, P=0.002).CONCLUSION: In patients with peptic ulcers, Hpylori vacA s1a and m1T prevent bleeding complication.

  20. Long-Term Pavement Performance (LTPP) InfoPave: Extracting Practical Information out of the Data

    OpenAIRE

    Ahmad, Riaz; Daleiden, Jerome; Kargah-Ostadi, Nima

    2015-01-01

    Long-Term Pavement Performance (LTPP) InfoPave is the web interface for the world's largest pavement performance database. This web interface is being developed under the Federal Highway Administration (FHWA) LTPP program to achieve the strategic goal of utilizing LTPP data effectively. An effective web interface helps reach users crossing all levels of expertise and geographical boundaries and helps information sharing which adds value to tax payers' dollars. To overcome the hurdles for easy...

  1. 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.

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

    OpenAIRE

    Baha Vural Kök; Mehmet Yılmaz; Alaaddin Geçkil

    2012-01-01

    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 ...

  3. 投稿须知%Construction Technology for Fast-Track Concrete Pavement

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    In this paper, one of new contents: construction technology for fast-track concrete pavement is introduced in 《Technical Specification for Construction of Highway Cement Concrete Pavements》 (JTG F30) which is revised in 2010 in order to not only provide high-quality and long-lasting life, but also reduce the time of engineering in the new construction, reconstruction and resurfacing maintain of cement concrete pavements, to quickly and early open public traffic, and to reduce traffic interruptions.

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

    OpenAIRE

    Gürer, Cahit; AKBULUT, Hüseyin; ÇETİN, Sedat

    2007-01-01

    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 w...

  5. Assessing the Impacts of Pavement Surface Condition on the Performance of Signalized Intersections

    OpenAIRE

    Hussein, Nasreen A.; Hassan, Rayya A.; Evans, Robert

    2015-01-01

    Signalized intersections are one of the most dangerous places on the road network as they carry a very high crash risk. This may be exacerbated by inadequate pavement surface condition. The main objective of this study was to assess the effect of pavement surface condition (in terms of skid resistance, roughness and rutting) at intersections and approaches on users' safety. In particular, this paper studied the change in crash frequency for numerous signalized intersections before and after s...

  6. Determination Of Correlation Between Road Pavement Skid Resistance And Braking Deceleration

    OpenAIRE

    KOKOT, D; Rijavec, R.; Ambroz, M.

    2012-01-01

    There are many situations when road pavement surface skid resistance drops to unacceptable levels. Skid resistance is an essential pavement property for road safety, but drivers are not able to assess its degree by visual means, although in the end they must be able to stop their vehicles safely within the stopping sight distance. In our research normalized braking deceleration was related to SCRIMTEX SFC values and analyzed for different driving conditions (wet/dry), vehicle systems, skid re...

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

    OpenAIRE

    Gabriele Bitelli; Andrea Simone; Fabrizio Girardi; Claudio Lantieri

    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 experime...

  8. Research on the relationship between water stability and aggregate gradation of asphalt pavement

    OpenAIRE

    Zhao Bing; Zhao Bo

    2015-01-01

    In the early destruction of asphalt pavement, water damage is the most major form.In this paper, experimental study was conducted on the composition of asphalt concrete,Marshall specimens were made in different types of aggregate gradation with the same kind of asphalt. Water immersion tests were conducted in order to analysis the relationship between the water stability and aggregate gradation of asphalt pavement.

  9. Investigating In Situ Properties of Recycled Asphalt Pavement with Foamed Asphalt as Base Stabilizer

    OpenAIRE

    Antonis Kaltsounis; Vasilis Papavasiliou; Andreas Loizos; Christina Plati

    2010-01-01

    The objective of the present study was to conduct a comprehensive field experiment for the in situ assessment of in-depth recycled asphalt pavement using foamed asphalt as a stabilization treatment for base works. For this purpose Nondestructive Testing (NDT) data collected using the Falling Weight Deflectometer (FWD) and Ground Penetrating Radar (GPR) along a foamed asphalt recycled pavement section was thoroughly analysed. Critical issues including the stabilized material curing and the con...

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

    Energy Technology Data Exchange (ETDEWEB)

    Pomerantz, Melvin; Akbari, Hashem; Harvey, John T.

    2000-06-01

    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.

  11. The Effect of Alternative Heavy Truck Suspensions on Flexible Pavement Response

    OpenAIRE

    Hedrick, J. K.; Yi, K.

    1991-01-01

    In this paper, the dynamic effects of heavy vehicle suspensions are investigated by analyzing parametric studies performed using previously developed simulation tools. In particular, the truck simulation package, VESYM, and the flexible pavement simulation package. VESYS, are used to look at the influence of alternative suspension types, e.g., walking beam, leaf spring/short rocker, air spring and semi-active shock absorbers on pavement response. The intent of the study is to determi...

  12. The influence of recycled asphalt pavement on 20mm binder course mix performance

    OpenAIRE

    Tabakovic, Amir; Gibney, Amanda; Gilchrist, M. D.; McNally, Ciaran

    2006-01-01

    This paper presents the results of ongoing research on the mechanical performance of a 20mm binder course asphalt pavement mix incorporating recycled asphalt pavement (RAP). A series of binder course mixes were designed containing varying percentages of RAP. A mix made only from virgin material was selected as the control mix for the investigation. The effect of introducing RAP into the binder course mix was evaluated through a series of laboratory tests including the Marshall Test, Indire...

  13. Calculating rutting of some thin flexible pavements from repeated load triaxial test data

    OpenAIRE

    Qiao, Yaning; Dawson, Andrew; Huvstig, Anders; Korkiala-Tanttu, Leena

    2015-01-01

    This paper describes parts of a Nordic pavement performance prediction model study (at the project level of the NordFoU project) where a material performance model, developed at VTT research centre in Finland, has been selected as a mean of calculating the permanently accumulated (plastic) deformation (i.e. rutting) of unbound granular materials (UGMs) in flexible pavements subjected to trafficking. The paper aims to assess the suitability of this VTT model application to Swedish roads compri...

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

    OpenAIRE

    Sañudo Fontaneda, Luis Ángel; Charlesworth, Susanne M.; Castro Fresno, Daniel; Andrés Valeri, Valero Carlos Alessio; Rodríguez Hernández, 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 a...

  15. Infrastructure Pavement Assessment & Management Applications Enabled by the Connected Vehicles Environment – Proof-of-Concept

    OpenAIRE

    Flintsch, Gerardo; Smith, Brian

    2015-01-01

    The objective of this project was to develop prototypes and conduct a field test of system level applications of a connected vehicle pavement condition measurement system. This allowed the research team to: (1) investigate different approaches to a connected vehicle pavement measurement system; and (2) determine the optimum procedures for collecting, processing, aggregating, and storing the data to support engineering and management decisions. The study found that roughness measures obtain...

  16. Modelling of Mechanical Properties of Cement Concrete Incorporating Reclaimed Asphalt Pavement

    OpenAIRE

    MATHIAS, Vincent; SEDRAN, Thierry; De Larrard, François

    2009-01-01

    In many countries there is a trend to recycle wastes obtained during pavement maintenance or reconstruction, and to forbid the landfill of these products. Thus, in some circumstances it can be tempting to use reclaimed asphalt pavement (RAP) in new hydraulic concrete mixtures. This paper presents experimental data and modelling about the effect of RAP incorporation on cement concrete mechanical properties (compressive strength, tensile strengths and E-modulus). All these properties tend to de...

  17. 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

  18. The prevalence of underlying bleeding disorders in patients with heavy menstrual bleeding with and without gynecologic abnormalities

    NARCIS (Netherlands)

    Knol, H. Marieke; Mulder, Andre; Bogchelman, Dick H.; Kluin-Nelemans, Hanneke C.; van der Zee, Ate G. J.; Meijer, Karina

    2013-01-01

    OBJECTIVE: The purpose of this study was to assess the prevalence of underlying bleeding disorders in women with heavy menstrual bleeding (HMB) with and without gynecologic abnormalities. STUDY DESIGN: We performed a single-center prospective cohort study of 112 consecutive patients who were referre

  19. The design and analysis on asphalt concrete pavement%沥青混凝土路面设计分析

    Institute of Scientific and Technical Information of China (English)

    王星茹

    2016-01-01

    This paper introduced the design process of urban road asphalt pavement,discussed the material and type of asphalt concrete pave-ment,from the pavement structure combination design,pavement design index,pavement structure layer calculation and other aspects,elabora-ted the design method of asphalt concrete pavement,made the asphalt pavement meet the structure strength and stability requirements.%介绍了城市道路沥青路面设计的流程,论述了沥青混凝土面层的材料与类型,从路面结构组合设计、路面设计指标、路面结构层计算等方面,阐述了沥青混凝土路面的设计方法,使沥青路面满足结构强度和稳定性的要求.

  20. Applying AHP—Based CBR to Estimate Pavement Maintenance Cost

    Institute of Scientific and Technical Information of China (English)

    Jui-Sheng Chou

    2008-01-01

    The cost-efficacy control of maintenance operations in developing countries has become critical to the infrastructure asset management after highway construction.To effectively manage numerous projects annually with limited resources,it is necessary to reasonably estimate costs during the process of making maintenance project selection decisions.This study outlines the modeling of case-based reasoning (CBR) estimation that compares and retrieves the most similar instance across the case library.Four CBR ap- proaches were presented and assessed in terms of their mean absolute prediction error rates.The resulting model demonstrates the ability of estimating the pavement maintenance project costs with the satisfactory accuracy at the early stages.

  1. Dynamic Modeling of Pavements with Application to Deflection Measurements

    DEFF Research Database (Denmark)

    Madsen, Stine Skov

    with different speeds is needed. In this thesis a new Finite Element formulation for transient dynamic loading of a layered half space is developed. Equations are derived in 2D and 3D and include efficient absorbing boundary conditions in the form of the Perfectly Matched Layer (PML) which ensures capability...... Deflectometer (RWD) type of device due to its ability to measure deflections continuously while driving at traffic speed. To be able to properly interpret deflection measurements from an RWD device, more knowledge about the structural behavior of a pavement when subjected to transient dynamic loads moving...... of long time simulations without disruptions from the boundaries. The equations are formulated in a moving frame of reference such that the domain is following the load, which ensures that the size of the model is kept small regardless of simulation time frame. A parametric study for finding optimal PML...

  2. Validation of theoretical models through measured pavement response

    DEFF Research Database (Denmark)

    Ullidtz, Per

    1999-01-01

    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...... 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...

  3. Research on nonlinear constitutive relationship of permanent deformation in asphalt pavements

    Institute of Scientific and Technical Information of China (English)

    PENG; Miaojuan; XU; Zhihong

    2006-01-01

    To predict correctly the rut depths in asphalt pavements,a new nonlinear viscoelastic-elastoplastic constitutive model of permanent deformation in asphalt pavements is presented.The model combines a generalized Maxwell model with an elastoplastic one.Then from the creep theory,the linear and nonlinear constitutive equations of the generalized Maxwell model are obtained.From the nonlinear finite element method for the rutting of the asphalt pavement,the rut depths of 4 asphalt-aggregate mixtures are obtained.And the results are compared with the ones from the finite element method by SHRP and the experiments by SWK/UN.The results in this paper are better than the ones by SHRP,and agree with the ones of the experiment by SWK/UN.This shows that the nonlinear viscoelastic-elastoplastic constitutive model,which is presented in this paper for the rutting of the asphalt pavement,is effective.The properties,such as nonlinear elasticity,plasticity,viscoelasticity and nonlinear viscoelasticity,which affect the rutting of an asphalt pavement,can be shown in the model.And the characteristics of the permanent deformation of the asphalt pavement can be presented entirely in the model.

  4. Pavement response to vehicular loads: a mechanistic approach involving nondestructive evaluation techniques

    Science.gov (United States)

    Kennedy, James C., Jr.

    1996-11-01

    The need for effective design in the nation's highways is greater now, more than ever, due to shrinking funds for new construction and rehabilitation/maintenance practices and the need to preserve the lands that are not now part of the roadway system. Most of the nation's highways were constructed within the last 30 years and many of these are due for significant rehabilitation and even reconstruction. Thus, the need to infuse robust design methods into these rehabilitation and reconstruction strategies is paramount. Currently, methods for cost allocation for pavement rehabilitation/maintenance activities and pavement management estimations are based on empirical and semi- empirical founded predictions that come up short, particularly when the roadway i subjected to multi-axle, heavy weight vehicles. Additionally, materials currently used int he construction of the pavement structure do not always behave in an elastic manner and the ability to predict the pavement response in the presence of other than elastic material behavior is essential. Finally, prediction of pavement states of distress based on empirical methods and elastic material behavior are inadequate, particularly when heavy weight vehicular traffic is involved. This paper includes descriptions of the overall methodology for pavement design and the unique requirements for the design and implementation of the structural and environmental sensing elements. Description of the mechanistic aspects in the software for the structural and material models is discussed and comparison of predicted and field measured results are presented.

  5. Thermal Behavior of an Asphalt Pavement in the Laboratory and in the Parking Lot

    Directory of Open Access Journals (Sweden)

    J. B. Martinkauppi

    2015-01-01

    Full Text Available 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.

  6. 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.

  7. 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.

  8. Sensitivity analysis of asphalt-pavement structure dynamic responses under heavy load

    Directory of Open Access Journals (Sweden)

    ZHANG Lijuan

    2015-04-01

    Full Text Available With the 3-Dimensional finite-element dynamic model,the influence of axis-load,axis-speed,and pavement structure parameters on dynamic performance of pavement structure is studied.The results show that with the increase in load,the dynamic response of pavement is nearly proportional to axis-load and increases noticeably;Axis-speed influences the dynamic response to some extent.With the increase of axis-speed,dynamic response of pavement structure increases firstly.With axis-speed further increasing,dynamic response of pavement structure then decreases gradually.For fatigue failure,the influence of heavy-load with common moving speed is much greater than that of static load.Among the pavement structure parameters,thickness of surface-layer has a significant effect on shear stress and the compression stress at road surface.Subgrade modulus has a significant effect on road surface deflection,tensile stress at the bottom of subbase,and compression-strain at the top of subgrade.

  9. Field validation of road roughness evaluation using in-pavement strain sensors

    Science.gov (United States)

    Zhang, Z.; Deng, F.; Huang, Y.; Bridgelall, R.

    2016-04-01

    Most transportation agencies now collect pavement roughness data using the inertial profilers, which requires instrumented vehicles and technicians with specialized training to interpret the results. The extensive labor requirements of the profiling activities limit data collection for portions of the national highway system to at most once per year, resulting in outdated roughness data for decision making of maintenance needs. In this paper, a real-time roughness evaluation method was developed by linking the output of durable in-pavement strain sensors to road roughness level. The durable in-pavement sensors will continuously provide information of road roughness in real time after they are installed and calibrated during the road construction until the service life of the associated pavement. Field tests validated the developed strain method by comparison with standard inertial profiling method and the connected-vehicle method. The comparison of the results from the field tests approves the effectiveness of the developed road roughness evaluation method using in-pavement strain sensors, which can be further applied practically for needed concrete pavements.

  10. 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

  11. New Asphalt Pavement Failure Criterion Based on Unifi ed Strength Theory

    Institute of Scientific and Technical Information of China (English)

    YANG Qun; CHEN Lu; WANG Ping; DAI Jingwang

    2015-01-01

    This study aims to introduce an appropriate analytical method for asphalt pavement based upon unified strength theory (UST). The traditional maximum shear stress strength theory (MSST) cannot describe the marked difference between tension strength and compressive strength or variable intermediate principal stress, which significantly affects the geotechnical materials. Our studies try to find a new asphalt pavement failure criterion that considers the influence of both tension-compression strength ratio and intermediate principal stress of asphalt mixture. In order to select a suitable theory on pavement material, the UST is introduced and compared with the traditional theory. Results show that the tension-compression strength ratio of asphalt mixture, which is used as a material parameter, dramatically affects the stress and stress distribution law in pavement; the pavement stress level increases dramatically after considering the intermediate principal stresses. Therefore, the UST which considers both tension-compression strength ratio and intermediate principal stress is more in line with the material characteristics of asphalt pavement.

  12. Synthesis Study on Use of Concrete Recycled from Pavement and Building Rubble in the Indiana Highway System

    OpenAIRE

    Burke, Thomas T.; Cohen, Menashi D.; Scholer, Charles F.

    1992-01-01

    The demolition of buildings and highway pavements in the State of Indiana generates a considerable amount of waste materials. The disposal of these materials causes strain on the existing landfills which are rapidly approaching their full capacity. This study is a synthesis of the information on the use of concrete recycled from pavements and building rubble for use in the Indiana highway system. Test results have shown that recycled pavement concrete made chiefly from broken-up and crushed o...

  13. Traffic noise abatement : how different pavements, vehicle speeds and traffic densities affect annoyance levels

    OpenAIRE

    Freitas, Elisabete F.; Mendonça, Catarina; Santos, Jorge A.; Murteira, Carla; Ferreira, João Amaro Oliveira

    2012-01-01

    In this paper, annoyance ratings from traffic noise recorded on cobblestones, dense asphalt, and open asphalt rubber pavements are assessed with regard to car speeds and traffic 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 significantly different. Higher car speeds always lead to greater annoyance, as does higher traffic densi- ties. LAeq and LAmax correl...

  14. Evaluation of a new experimental test procedure to more accurately determine the surface infiltration rate of permeable pavement systems

    OpenAIRE

    Lucke, T.; Boogaard, F.; Van den Ven, F.

    2014-01-01

    Permeable pavements are specifically designed to promote the infiltration of stormwater through the paving surface in order to reduce run-off volumes and to improve water quality by removing sediment and other pollutants. However, research has shown that permeable pavements can become clogged over time and this reduces their infiltration capacity. In order to assess the infiltration of permeable pavements, a variety of infiltration test procedures have been utilised in the past. However, the ...

  15. Current State and Expectation in Diagnosis and Treatment of Bleeding Disorders

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-yue王兆钺

    2002-01-01

    @@ 1 Classification and sreening tests of bleeding disorders Under the heading of bleeding disorders are grouped a number of diseases which have hemorrhagic problems. Bleeding disorders are very common, involving about one third of patients in the hematological consultation.

  16. Bleeding from gums: Can it be a dengue

    Directory of Open Access Journals (Sweden)

    Rajat Bansal

    2014-01-01

    Full Text Available Introduction: Bleeding from gums is a common feature in periodontitis patient. But abnormal bleeding from the gingiva or other areas of the oral mucosa that is difficult to control is an important clinical sign suggesting a hematological disorder. Case Report: A-40-year old male patient reported to our clinic with the chief complaint of acute gingival bleeding. There was continuous bleeding, fever since 3-4 days with weakness, retro orbital pain, and severe backache. Patient gave a history of bleeding from gums for last 24 hrs. His blood profile revealed; platelet count of 36,000, total wite blood cell (WBC count of 6000/cumm, differential leukocyte count (DLC (P45, L53, E2, and hemoglobin 12 g/dL. Patient sera was positive for dengue non-structural protein-1 antigen, anti-dengue immunoglobulin M (IgM, and anti-dengue immunoglobulin G (IgG antibodies. Discussion: Here is a case report capable of changing our vision that acute gingival bleeding can also occur in dengue fever. Dengue fever can also be considered as one of the differential diagnosis for the acute gingival bleeding.

  17. PRE-AETHIOLOGICAL TREATMENT IN UPPER GASTRO-INTESTINAL BLEEDING

    Directory of Open Access Journals (Sweden)

    G. Dimofte

    2005-01-01

    Full Text Available Upper gastro-intestinal bleeding remains a cornerstone in surgical practice and unfortunately its’ management is profoundly variable according to hospital protocols and local standards of care. Medical interventions are acting at different levels of medical care and a range of specialist are involved in the process, starting from family practitioners to surgeons, as well as highly trained specialist in interventional endoscopy or radiology. This review is trying to establish the landmarks in the early assessment and care of patients with upper gastro-intestinal bleeding, irrespective of the morphological cause of the bleeding. We propose a protocol for the management both of portal and non-portal upper-gastrointestinal bleedings, prior to endoscopic diagnosis. It is fundamental to establish a standard of care which is feasible in Romania and can work both in university and district hospitals. The protocol is marking the essential gestures with their relevance for the bleeding patient but also reminds the significance of clinical evaluation and safety in transportation of the patient to the nearest emergency room. A battery of simple test should be performed in every patient and data interpreted with care, as results vary according to the level of haemodynamic compensation. Standard empiric therapy for upper gastro-intestinal bleeding is not yet been established but a couple of alternatives emerge as possible solutions. We discuss the benefits of a standard therapy based on H2 blockers, proton pump inhibitors, octreoctide and somatostatin regarding both portal and non-portal bleedings.

  18. Quality laboratory issues in bleeding disorders.

    Science.gov (United States)

    Adcock, D M; Mammen, J; Nair, S C; de Lima Montalvão, S A

    2016-07-01

    Selected quality issues pertinent to the determination of accurate results in the haemostasis laboratory are discussed. Specifically, the implementation of a successful external quality-assessment scheme is described, including its impact on result accuracy as well as the programme's unique challenges and opportunities. Errors in the preanalytical phase of laboratory testing represent the greatest source for reporting incorrect test results. Some of the most common preanalytical errors are described including those that necessitate sample rejection. Analytical means to identify potential sources of error and analytical means to overcome particular interferences are described. Representing the most important clinical complication in the treatment of patients with haemophilia, quality issues related to determination of the presence of inhibitory antibodies against factor VIII (FVIII) are reviewed. Heat treatment of patient plasma prior to testing, particularly in patients receiving replacement FVIII concentrate or during induction of immune tolerance to achieve more accurate results is recommended, while screening activated partial thromboplastin time-based mixing tests to rule out inhibitor presence is discouraged. The initiatives presented in this review can be implemented in robust and resource restricted settings to improve the quality of laboratory testing in patients with bleeding disorders. PMID:27405682

  19. Selective serotonin reuptake inhibitors and the risk of bleeding

    Directory of Open Access Journals (Sweden)

    Padma L

    2013-06-01

    Full Text Available Background: Selective serotonin reuptake inhibitors (SSRIs are commonly prescribed agents for various conditions in general psychiatry. There is a strong consensus that blockade of serotonin reuptake affects primary hemostasis, namely platelet activity, thus resulting in a bleeding tendency. Considering that SSRIs are commonly prescribed, this study was conducted to assess if they were associated with an increased risk of bleeding. Methods: This was a prospective, open-label study of 30 patients attending the Psychiatry out-patient department, Dr. B. R. Ambedkar Medical College, Bangalore who satisfied DSM-IV criteria for a primary diagnosis of depression, treated with SSRIs. Bleeding time, clotting time, prothrombin time, partial thromboplastin time and platelet count were assessed at baseline and at the end of 6 weeks of treatment or occurrence of bleeding symptom. Results: The patients aged between 18-55 years of whom 21 were females, were treated with an SSRI (fluoxetine 12, escitalopram 12 and sertraline 6 patients. Six patients had overt symptoms of bleeding (upper gastrointestinal bleeding (hematemesis 4; epistaxis 2 and petechiae 2 of whom one patient gave a history of both hematemesis and petechiae and another of hematemesis and epistaxis. The average day after treatment beginning, on which patients reported with bleeding was 30.33 (26-40 days. There was a significant increase in the bleeding time (p=0.028 and clotting time (p=0.042, implying derangement in platelet aggregation. There was no significant change in the other parameters. Conclusion: Treatment with SSRIs increases the risk of bleeding. However, large, randomized controlled trials are required to re-affirm these findings. [Int J Basic Clin Pharmacol 2013; 2(3.000: 272-274

  20. Clival chordoma manifesting as nasal bleeding. A case report

    Energy Technology Data Exchange (ETDEWEB)

    Kitai, Ryuhei; Yoshida, Kazuhiko; Kubota, Toshihiko; Sato, Kazufumi; Handa, Yuji; Kasahara, Kazuma [University of Fukui, Department of Neurosurgery, Fukui (Japan); Nakajima, Hirofumi [Tsuruga Municipal Hospital, Department of Neurosurgery, Fukui (Japan)

    2005-05-01

    Chordoma is a rare cartilaginous tumor, for which bleeding presentation is unusual. We report a case of rare hemorrhaged clival chordoma, which was diagnosed correctly by magnetic resonance imaging. A 32-year-old man presented with nasal bleeding. The tumor was totally removed via a trans-sphenoidal approach, from which the surgical specimen confirmed chordoma. Epistaxis seemed to be caused by the spreading of the intratumoral hemorrhage into the sphenoid sinus. This case demonstrates the importance of an exact differential diagnostic evaluation, including chordoma, by use of modern imaging techniques for nasal bleeding. (orig.)

  1. ULTRASONOGRAPHIC EVALUATION OF PREGNANCY WITH BLEEDING PER VAGINA

    Directory of Open Access Journals (Sweden)

    Amit C

    2014-12-01

    Full Text Available This study of 150 patients presenting with bleeding per vagina in first, second & third trimester was conducted to evaluate the cause of bleeding, access the severity of condition, to predict the later coarse of pregnancy & to evaluate the role of ultrasonography in management. This study was conducted in department of Radiology at Basaweshwar Teaching & General hospital, Government general hospital & Sangameshwer teaching & General hospital. This study concludes that, Ultrasonography should be the first line of investigation in all the cases of bleeding per vagina in pregnancy

  2. Splenic angiosarcoma metastasis to small bowel presented with gastrointestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    Jun-Te Hsu; Chin-Yew Lin; Ting-Jun Wu; Han-Ming Chen; Tsann-Long Hwang; Yi-Yin Jan

    2005-01-01

    Primary splenic angiosarcoma is a very rare,aggressive neoplasm with a high metastatic rate and dismal prognosis. This neoplasm usually presents with abdominal pain, splenomegaly, anemia, and thrombocytopenia. Splenic angiosarcoma with bleeding gastrointestinal metastases is extremely rare. The literature contains only two case reports. This study reported a 44-year-old male patient with splenic angiosarcoma with sustained repeated gastrointestinal bleeding due to small bowel metastases. Salvage surgery was performed by splenectomy and resection of the metastatic small bowel tumors. The post-operative course was uneventful; the patient survived with the disease and had no GI bleeding, 7 mo after surgery.

  3. Interventional angiography in the diagnosis of acute lower gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Interventional angiography with the use of indwelling arterial catheters, anticoagulants, vasodilators and fibrinolytic agents, complements conventional angiography in the diagnosis of acute lower gastrointestinal bleeding. These interventional techniques prolong, augment or reactive bleeding and, by enabling better timing of examinations, they increase the diagnostic efficacy of angiography. In the reported series of 63 patients with acute lower gastrointestinal hemorrhage, interventions increased the diagnostic yield of angiography for demonstration of extravasation from 32% to 65% and decreased the percentage of negative angiograms from 27% to 16%. Indications, techniques and risks of interventional angiography in the diagnosis of acute lower gastrointestinal bleeding are discussed. (orig.)

  4. Scintigraphic demonstration of gastrointestinal bleeding due to mesenteric varices

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, M.E.; Coleman, R.E. (Duke Univ. Medical Center, Durham, NC (USA))

    1990-07-01

    Mesenteric varices can appear as massive, acute lower gastrointestinal bleeding. The small bowel or colon may be involved, varices usually developing at sites of previous surgery or inflammation in patients with portal hypertension. Two patients with alcoholic cirrhosis and protal hypertension presented with rectal bleeding. Tc-99m RBC studies demonstrated varices and extravasation into the adjacent bowel. The varices were documented by mesenteric angiography. Characteristic features of Tc-99m labeled RBC studies can identify mesenteric varices as the cause of intestinal bleeding and localize the abnormal vessels.

  5. Risk of bleeding related to antithrombotic treatment in cardiovascular disease

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Olesen, Jonas B; Charlot, Mette;

    2012-01-01

    Antithrombotic therapy is a cornerstone of treatment in patients with cardiovascular disease with bleeding being the most feared complication. This review describes the risk of bleeding related to different combinations of antithrombotic drugs used for cardiovascular disease: acute coronary...... syndrome (ACS), atrial fibrillation (AF), cerebrovascular (CVD) and peripheral arterial disease (PAD). Different risk assessment schemes and bleeding definitions are compared. The HAS-BLED risk score is recommended in patients with AF and in ACS patients with AF. In patients with ACS with or without...

  6. Embolization of Bleeding Stomal Varices by Direct Percutaneous Approach

    International Nuclear Information System (INIS)

    Stomal varices can occur in patients with stoma in the presence of portal hypertension. Suture ligation, sclerotherapy, angiographic embolization, stoma revision, beta blockade, portosystemic shunt, and liver transplantation have been described as therapeutic options for bleeding stomal varices. We report the case of a 21-year-old patient with primary sclerosing cholangitis and colectomy with ileostomy for ulcerative colitis, where stomal variceal bleeding was successfully treated by direct percutaneous embolization. We consider percutaneous embolization to be an effective way of treating acute stomal bleeding in decompensated patients while awaiting decisions regarding shunt procedures or liver transplantation.

  7. Bleeding following deep hypothermia and circulatory arrest in children.

    Science.gov (United States)

    Mossad, Emad B; Machado, Sandra; Apostolakis, John

    2007-03-01

    Deep hypothermic circulatory arrest (DHCA) is a technique of extracorporeal circulation commonly used in children with complex congenital heart defects undergoing surgical repairs. The use of profound cooling (20 degrees C) and complete cessation of circulation allow adequate exposure and correction of these complex lesions, with enhanced cerebral protection. However, the profound physiologic state of DHCA results in significant derangement of the coagulation system and a high incidence of postoperative bleeding. This review examines the impact of DHCA on bleeding and transfusion requirements in children and the pathophysiology of DHCA-induced platelet dysfunction. It also focuses on possible pharmacologic interventions to decrease bleeding following DHCA in children. PMID:17484172

  8. Prediction of bleeding and prophylactic platelet transfusions in cancer patients with thrombocytopenia

    DEFF Research Database (Denmark)

    Vinholt, Pernille J; Alnor, Anne; Nybo, Mads;

    2016-01-01

    platelet transfusion within 30 days were registered. Of 197 patients enrolled, 56 (28%) experienced bleeding. In multivariate analyses, predictors of bleeding were infection (adjusted odds ratio (OR) = 2.65 and 95% confidence interval (95% CI) 1.04-6.74); treatment with platelet inhibitors, heparin...... platelet transfusion but not bleeding. Bleeding risk factors were previous haematuria or gastrointestinal bleeding, infection, antiplatelet or anticoagulant treatment, high urea nitrogen, low haemoglobin or high creatinine.......Studies on markers for bleeding risk among thrombocytopenic cancer patients are lacking. This prospective observational cohort study investigated whether platelet parameters and a standardised bleeding questionnaire predicted bleeding or prophylactic platelet transfusions in patients with cancer...

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

    Science.gov (United States)

    Kowalski, Karol J.

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

  10. Anode reactive bleed and injector shift control strategy

    Science.gov (United States)

    Cai, Jun [Rochester, NY; Chowdhury, Akbar [Pittsford, NY; Lerner, Seth E [Honeoye Falls, NY; Marley, William S [Rush, NY; Savage, David R [Rochester, NY; Leary, James K [Rochester, NY

    2012-01-03

    A system and method for correcting a large fuel cell voltage spread for a split sub-stack fuel cell system. The system includes a hydrogen source that provides hydrogen to each split sub-stack and bleed valves for bleeding the anode side of the sub-stacks. The system also includes a voltage measuring device for measuring the voltage of each cell in the split sub-stacks. The system provides two levels for correcting a large stack voltage spread problem. The first level includes sending fresh hydrogen to the weak sub-stack well before a normal reactive bleed would occur, and the second level includes sending fresh hydrogen to the weak sub-stack and opening the bleed valve of the other sub-stack when the cell voltage spread is close to stack failure.

  11. A rare cause of recurrent gastrointestinal bleeding: mesenteric hemangioma

    Directory of Open Access Journals (Sweden)

    Zeytunlu Murat

    2009-01-01

    Full Text Available Abstract Lower gastrointestinal hemorrhage accounts for approximately 20% of gastrointestinal hemorrhage. The most common causes of lower gastrointestinal hemorrhage in adults are diverticular disease, inflammatory bowel disease, benign anorectal diseases, intestinal neoplasias, coagulopathies and arterio-venous malformations. Hemangiomas of gastrointestinal tract are rare. Mesenteric hemangiomas are also extremely rare. We present a 25-year-old female who was admitted to the emergency room with recurrent lower gastrointestinal bleeding. An intraluminal bleeding mass inside the small intestinal segment was detected during explorative laparotomy as the cause of the recurrent lower gastrointestinal bleeding. After partial resection of small bowel segment, the histopathologic examination revealed a cavernous hemagioma of mesenteric origin. Although rare, gastrointestinal hemangioma should be thought in differential diagnosis as a cause of recurrent lower gastrointestinal bleeding.

  12. Post-biliary sphincterotomy bleeding despite covered metallic stent deployment

    Science.gov (United States)

    Donatelli, Gianfranco; Cereatti, Fabrizio; Dumont, Jean-Loup; Dhumane, Parag; Tuszynski, Thierry; Vergeau, Bertrand Marie; Meduri, Bruno

    2016-01-01

    Objectives: Several endoscopic techniques have been proposed for the management of post-sphincterotomy bleeding. Lately, self-expandable metal stents deployment has gained popularity especially as a rescue therapy when other endoscopic techniques fail. Methods-results: We report the case report of a massive post-sphincterotomy bleeding in a patient with a self-expandable metal stent in the biliary tree. Despite the presence of a correctly positioned self-expandable metal stent, a new endoscopic session was required to control the bleeding. Conclusions: Self-expandable metal stent may be useful to manage post-endoscopic sphincterotomy bleeding. However, up to now there is no specifically designed self-expandable metal stent for such complication. Large new designed self-expandable metal stent may be a useful tool for biliary endoscopist. PMID:27489716

  13. Fibrinogen concentrates for bleeding trauma patients: what is the evidence?

    DEFF Research Database (Denmark)

    Meyer, Martin; Ostrowski, S R; Windeløv, N A;

    2011-01-01

    A balanced transfusion of red blood cells, fresh frozen plasma and platelets are recommended for massively bleeding trauma patients. Fibrinogen concentrates could potentially lessen or replace the need for fresh frozen plasma and/or platelet transfusions....

  14. Modern issues on the treatment of peptic ulcer bleedings

    Directory of Open Access Journals (Sweden)

    Potakhin S.N.

    2014-03-01

    Full Text Available Despite the success of therapeutic treatment of peptic ulcer and the introduction of endoscopic technologies, the problem of peptic ulcer hemorrhage remains valid. A large number of publications in foreign literature are dedicated to epidemiology and prevention of bleeding, evaluation of modern tactics and search for new methods of treatment. The works relating to organization of aid to patients with peptic ulcer bleeding are of particular interest. According to the recent data not all clinics even in economically developed countries manage to follow the recommendations of an international consensus-2010 for non-variceal bleeding treatment of upper gastrointestinal tract. Among the causes of non-compliance of international recommendations there are subjective and objective factors, the understanding of which can significantly affect the optimization of aid to patients with peptic ulcer bleeding.

  15. Risk of bleeding related to antithrombotic treatment in cardiovascular disease

    DEFF Research Database (Denmark)

    Sørensen, Rikke; Olesen, Jonas B; Charlot, Mette;

    2012-01-01

    Antithrombotic therapy is a cornerstone of treatment in patients with cardiovascular disease with bleeding being the most feared complication. This review describes the risk of bleeding related to different combinations of antithrombotic drugs used for cardiovascular disease: acute coronary...... syndrome (ACS), atrial fibrillation (AF), cerebrovascular (CVD) and peripheral arterial disease (PAD). Different risk assessment schemes and bleeding definitions are compared. The HAS-BLED risk score is recommended in patients with AF and in ACS patients with AF. In patients with ACS with or without...... a stent dual antiplatelet therapy with a P2Y12 receptor antagonist and acetylsalicylic acid (ASA) is recommended for 12 months, preferable with prasugrel or ticagrelor unless there is an additional indication of warfarin or increased risk of bleeding. In patients with AF, warfarin is recommended...

  16. Pregnancy Complications: Bleeding and Spotting from the Vagina

    Science.gov (United States)

    ... problem, but they can be a sign of miscarriage or other serious complications. Miscarriage is when a baby dies in the womb ... is a sign of a serious problem, like: Miscarriage . Almost all women who miscarry have bleeding or ...

  17. Recent trends of study on esophageal variceal bleeding

    Institute of Scientific and Technical Information of China (English)

    CHENG Liu-fang; LI Chang-zheng

    2010-01-01

    @@ Esophageal variceal bleeding (EVB), a severe complication and main mortality cause of portal hypertension, had reached a relatively mature stage in its research. The mortality rate of EVB within 5 days showed decreased tendency in recent years, which may be due to wide adoption of endoscopic variceal ligation (EVL) and endoscopic injection sclerotherapy (EIS).1 Endoscopic treatment had been widely used because of its simple procedure, high hemostasis rate and low recurrent bleeding rate, and had become a main measure in cease of first episode and prevention of recurrent bleeding. The technique of endoscopic procedures had less progress in the last 5 years. Recent studies on EVB mainly focused on further improvement of clinical outcome, including primary prevention by EVL, selection and combination of different hemostatic measures, minimizing complications, better long-term management and forecast of bleeding risk.

  18. Numerical analysis of applying special pavements to solve the frost heave diseases of high-speed railway roadbeds in seasonally frozen ground regions

    Institute of Scientific and Technical Information of China (English)

    Chang Yuan; FuJun Niu; QiHao Yu; XinBin Wang; Lei Guo; YanHui You

    2015-01-01

    The Haerbin-Dalian Passenger Dedicated Line is the first high-speed railway constructed in the seasonally frozen ground regions of northeastern China. Frost heave diseases occurred in the first winter of its operation (between October 2012 and January 2013), and frost heave was observed mainly in the roadbed fills that were considered not susceptible to frost heave. This paper proposes applying two special pavements — black pavement and insulation-black pavement — to improve the thermal regime of the roadbed. Three numerical models of the roadbed temperature field were built based on the field con-ditions of the Changchun section (D3K692+840 to D3K692+860). The results show that: (1) Compared with cement pave-ment, black pavement and insulation-black pavement could reduce the freezing index at the roadbed surface by 37% and 64%, respectively, which could influence the maximum frozen depth; (2) the maximum frozen depths under the black pavement and insulation-black pavement were respectively 1.3–1.4 m and 1 m. Compared with cement pavement, they could reduce the maximum frozen depth by 0.4 m and 0.7–0.8 m, respectively, which would reduce the permitted amount of frost heave by 4 mm and 7–8 mm, which would meet the deformation limit established by theCode for Design on Special Subgrade of Railway; (3) the freezing periods of the black pavement and the insulation-black pavement were, respectively, approximately four months and two months. Compared with cement pavement, they could reduce the freezing period by approximately 19 days and 40 days, respectively, and delay the initial freezing time by 9 days and 18 days; and (4) compared with cement pavement, black pavement and black-insulation pavement could reduce the frozen areas of roadbeds in the cold season, which suggests that these two special pavements could provide better thermal stability for roadbeds.

  19. Therapeutic angiography for giant bleeding gastro-duodenal artery pseudoaneurysm

    Institute of Scientific and Technical Information of China (English)

    Ram; Elazary; Mahmoud; Abu-Gazala; Avraham; Schlager; Noam; Shussman; Avraham; I; Rivkind; Allan; I; Bloom

    2010-01-01

    We present the case of an 18-year-old female transferred to our center from an outside hospital due to persistent gastrointestinal bleeding. Two weeks prior to her transfer she underwent duodenal omentopexy for a perforated duodenal peptic ulcer. The patient underwent a computed tomography angiogram which identified the source of bleeding as a giant gastroduodenal artery (GDA) pseudoaneurysm. The patient was taken to interventional radiology where successful microcoil embolization was performed. We present ...

  20. Apoplexy in an intradural clival chordoma causing intraventricular bleed

    Science.gov (United States)

    Mohindra, Sandeep; Kapoor, Ankur; Kursa, Gopi Krishna; Mohindra, Satyawati; Saikia, Uma

    2016-01-01

    Background: A few cases depicting apoplexy in a chordoma have been reported. Rarely, this intratumoral bleed may spillover into intracerebral or intraventricular regions. Case Description: The authors report an intradural variety of clival chordoma presenting with apoplexy and spillover of blood into lateral ventricle. Clinical presentation, radiological scans, and relevant literature is also described. Conclusions: In a stable case of clival chordoma, intratumoral bleed or apoplexy may cause rapid neurological worsening and warranting urgent surgical intervention. PMID:26862453

  1. Transarterial embolization for management of severe postcoital bleeding

    Directory of Open Access Journals (Sweden)

    Armen Eskandari

    2016-08-01

    Full Text Available Objectives: Postcoital bleeding is an uncommon cause of gynecologic hemorrhage; however, it can be severe in a majority of cases necessitating surgical management. Methods: We report a case of severe postcoital bleeding in a young woman requiring blood transfusion. Results: Hemostasis was achieved using subselective embolization of cervical artery by metallic coils. Conclusion: Our case demonstrates a minimally invasive treatment for control of non-obstetric hemorrhage.

  2. Double-balloon enteroscopy in detecting small intestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    ZHI Fa-chao; PAN De-shou; ZHOU Dian-yuan; XIAO Bing; JIANG Bo; WAN Tian-mo; GUO Yu; ZHOU Dan; WANG Li-hui; CHEN Jin-feng; XIE Lu

    2005-01-01

    @@ Digestive tract hemorrhage is a common disease of the digestive system, but about 0.4%-5% intestinal bleeding can not be detected with gastroscope or colonscope.1 Since the intestine is long, tortuous, far away from both ends of the digestive tract and unfixed in position, clinical diagnosis of the bleeding is relatively difficult. Yamamoto and Sugano2 reported the clinical application of double-balloon enteroscope at American DDW in 2003.

  3. The Significance of Small Cerebral Bleeds in Neurodegenerative Dementia Syndromes

    OpenAIRE

    De Reuck, Jacques L.

    2012-01-01

    Small cerebral bleeds are frequently observed in brains of patients with Alzheimer disease (AD) and cerebral amyloid angiopathy (CAA). However, they are also observed in patients with other neurodegenerative dementias and in persons without cognitive impairment. The aim of this survey is to compare the bleeding load in brains with different dementia syndromes and in age-matched controls. Hundred sixty-five brains were examined. The prevalence and the severity of the different cerebrovascular ...

  4. Fibrinogen concentrates for bleeding trauma patients: what is the evidence?

    DEFF Research Database (Denmark)

    Meyer, Martin; Ostrowski, S R; Windeløv, N A;

    2011-01-01

    A balanced transfusion of red blood cells, fresh frozen plasma and platelets are recommended for massively bleeding trauma patients. Fibrinogen concentrates could potentially lessen or replace the need for fresh frozen plasma and/or platelet transfusions.......A balanced transfusion of red blood cells, fresh frozen plasma and platelets are recommended for massively bleeding trauma patients. Fibrinogen concentrates could potentially lessen or replace the need for fresh frozen plasma and/or platelet transfusions....

  5. Fallot′s tetralogy presenting with variceal bleed.

    Directory of Open Access Journals (Sweden)

    Kejariwal D

    2001-07-01

    Full Text Available The erythrocytosis of Fallot′s tetralogy may lead to spontaneous thrombosis at any site, but splenic vein thrombosis and variceal bleed is rarely a presentation of Fallot′s tetralogy. A case of a 48 years old female with undiagnosed Fallot′s tetralogy, presenting with variceal bleed due to splenic vein thrombosis, is reported. It is also interesting to note that the patient survived till this age without any medical or surgical treatment.

  6. Practical Approach to Endoscopic Management for Bleeding Gastric Varices

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Young Suk [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    2012-02-15

    Bleeding from gastric varices is generally more severe than bleeding from esophageal varices, although it occurs less frequently. Recently, new endoscopic treatment options and interventional radiological procedures have broadened the therapeutic armamentarium for gastric varices. This review provides an overview of the classification and pathophysiology of gastric varices, an introduction to current endoscopic and interventional radiological management options for gastric varices, and details of a practical approach to endoscopic variceal obturation using N-butyl-2-cyanoacrylate.

  7. Lessons Learned from Animal Models of Inherited Bleeding Disorders

    OpenAIRE

    Nichols, Timothy C.

    2014-01-01

    Advances in treatment of hemophilia and von Willebrand disease (VWD) depend heavily on the availability of well-characterized animal models. These animals faithfully recapitulate the severe bleeding phenotype that occurs in humans with these inherited bleeding disorders. Research in these animal models represents important early and intermediate steps of translational research aimed at addressing current limitations in treatment such as the development of inhibitory antibodies to coagulation ...

  8. Prolonged bleeding on the neck in leech therapy: Case report

    OpenAIRE

    Atakan Savrun; Selim Bozkurt; Mehmet Okumus; Emre Gokcen; Murat Turkaslan

    2015-01-01

    Superficial skin bleeding can usually be stopped by applying short-time compression, unless the patient suffers from coagulation disorders or uses anticoagulant. Because of the anticoagulant component of leech saliva, a leech bite may cause long-time bleeding, which cannot be stopped via compression. In this study, the case of a patient who applied leech therapy on her neck for the treatment of migraine has been presented. [Arch Clin Exp Surg 2015; 4(4.000): 234-237

  9. An unusual cause of upper gastrointestinal system bleeding: Duodenal varices

    OpenAIRE

    Yılmaz, Ömer; Ataseven, Hilmi

    2012-01-01

    Abstract Duodenal varices are an uncommon site of hemorrhage in patients with portal hypertension, but their rupture is a serious and often fatal event. We report the case of a 27- year- old man with liver cirrhosis who presented with upper gastrointestinal bleeding. Upper gastrointestinal endoscopy revealed nodular varices in the second portion of the duodenum which were considered to be the source of bleeding. We decided to inject N-butyl-2-cyanoacrylate (Histoacryl), an adhesive agent, and...

  10. Endoscopic Removal of an Unusual Foreign Body Causing Gastrointestinal Bleeding

    Directory of Open Access Journals (Sweden)

    A. Karaman

    2010-09-01

    Full Text Available Foreign body ingestion is a condition more common in the pediatric population than in adults. In adults, although foreign body ingestion can be well tolerated, approximately 10–20% of patients require endoscopic intervention. Delayed diagnosis and unremoved foreign bodies can cause serious and fatal complications including perforation, fistula and gastrointestinal bleeding. Here we report a patient with bleeding duodenal ulcer thought to be initiated by a large foreign body.

  11. On-site inspections of pavement damages evolution using GPR

    Science.gov (United States)

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

    2014-05-01

    Ground-penetrating radar (GPR) is being increasingly used for pavements maintenance due to the wide range of applications spanning from physical to geometrical inspections, thereby allowing for a reliable diagnosis of the main causes of road structural damages. In this work, an off-ground GPR system was used to investigate a large-scale rural road network. Two sets of surveys were carried out in different time periods, with the main goals to i) localize the most critical sections; ii) monitor the evolution of previous damages and localize newborn deep faults, although not revealed at the pavement surface level; iii) analyze the causes of both evolution and emergence of faults by considering environmental and human factors. A 1-GHz GPR air-launched antenna was linked to an instrumented van for collecting data at traffic speed. Other support techniques (e.g. GPS data logger, odometer, HD video camera) were used for cross-checking,. Such centre frequency of investigation along with a 25-ns time window allow for a signal penetration of 900 mm, consistent with the deepest layer interfaces. The bottom of the array was 400 mm over the surface, with a minimum distance of 1200 mm from the van body. Scan length of maximum 10 km were provided for avoiding heavy computational loads. The rural road network was located in the District of Rieti, 100 km north from Rome, Italy, and mostly develops in a hilly and mountainous landscape. In most of the investigated roads, the carriageway consists in two lanes of 3.75 meters wide and two shoulders of 0.50 meters wide. A typical road section includes a HMA layer (65 mm average thickness), a base layer (100 mm average thickness), and a subbase layer (300 mm average thickness), as described by pavement design charts. The first set of surveys was carried out in two days at the beginning of spring in moderately dry conditions. Overall, 320-km-long inspections were performed in both travel directions, thereby showing a productivity of

  12. Diagnosis and therapy of non-variceal upper gastrointestinal bleeding

    Institute of Scientific and Technical Information of China (English)

    Erwin; Biecker

    2015-01-01

    Non-variceal upper gastrointestinal bleeding(UGIB) is defined as bleeding proximal to the ligament of Treitz in the absence of oesophageal, gastric or duodenal varices. The clinical presentation varies according to the intensity of bleeding from occult bleeding to melena or haematemesis and haemorrhagic shock. Causes of UGIB are peptic ulcers, Mallory-Weiss lesions,erosive gastritis, reflux oesophagitis, Dieulafoy lesions or angiodysplasia. After admission to the hospital a structured approach to the patient with acute UGIB that includes haemodynamic resuscitation and stabilization as well as pre-endoscopic risk stratification has to be done. Endoscopy offers not only the localisation of the bleeding site but also a variety of therapeutic measures like injection therapy, thermocoagulation or endoclips. Endoscopic therapy is facilitated by acid suppression with proton pump inhibitor(PPI) therapy. These drugs are highly effective but the best route of application(oral vs intravenous) and the adequate dosage are still subjects of discussion. Patients with ulcer disease are tested for Helicobacter pylori and eradication therapy should be given if it is present. Non-steroidal antiinflammatory drugs have to be discontinued if possible. If discontinuation is not possible, cyclooxygenase-2 inhibitors in combination with PPI have the lowest bleeding risk but the incidence of cardiovascular events is increased.

  13. Liquefied Bleed for Stability and Efficiency of High Speed Inlets

    Science.gov (United States)

    Saunders, J. David; Davis, David; Barsi, Stephen J.; Deans, Matthew C.; Weir, Lois J.; Sanders, Bobby W.

    2014-01-01

    A mission analysis code was developed to perform a trade study on the effectiveness of liquefying bleed for the inlet of the first stage of a TSTO vehicle. By liquefying bleed, the vehicle weight (TOGW) could be reduced by 7 to 23%. Numerous simplifying assumptions were made and lessons were learned. Increased accuracy in future analyses can be achieved by: Including a higher fidelity model to capture the effect of rescaling (variable vehicle TOGW). Refining specific thrust and impulse models ( T m a and Isp) to preserve fuel-to-air ratio. Implementing LH2 for T m a and Isp. Correlating baseline design to other mission analyses and correcting vehicle design elements. Implementing angle-of-attack effects on inlet characteristics. Refining aerodynamic performance (to improve L/D ratio at higher Mach numbers). Examining the benefit with partial cooling or densification of the bleed air stream. Incorporating higher fidelity weight estimates for the liquefied bleed system (heat exchange and liquid storage versus bleed duct weights) could be added when more fully developed. Adding trim drag or 6-degree-of-freedom trajectory analysis for higher fidelity. Investigating vehicle optimization for each of the bleed configurations.

  14. Ultrasound contrast agents for bleeding detection and acoustic hemostasis

    Science.gov (United States)

    Zderic, Vesna; Luo, Wenbo; Brayman, Andrew; Crum, Lawrence; Vaezy, Shahram

    2005-04-01

    Objective: To investigate the application of ultrasound contrast agents (UCA) in improving both therapeutic and diagnostic aspects of ultrasound-guided High Intensity Focused Ultrasound (HIFU) therapy. Methods: Incisions (3 cm long, 0.5 cm deep) were made in rabbit livers (in anterior surface for HIFU treatment, or posterior surface for bleeding detection). UCA Optison (~0.1 ml/kg) was injected into mesenteric vein or ear vein. A HIFU applicator (5.5 MHz, 6400 W/cm2) was scanned manually over the incision until hemostasis was achieved. Occult bleeding was monitored with Doppler ultrasound. Results: The presence of Optison produced 37% reduction in hemostasis times normalized to initial bleeding rates. Gross and histological observations showed similar appearance of HIFU lesions produced in the presence of Optison and control HIFU lesions. The temperature reached 100°C in both HIFU only and HIFU+UCA treatments. Tension strength of hemostatic liver incisions was 0.9+/-0.5 N. Almost no bleeding could be detected before Optison injection. First appearance of contrast enhancement localized at the bleeding site was 15 s after Optison injection, and lasted for ~50 s. Conclusion: The presence of UCA during HIFU treatment of liver incisions resulted in shortening of HIFU application times and better visualization of bleeding sites.

  15. Congenital portosystemic shunts with and without gastrointestinal bleeding - case series

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Ying; Chen, Jun; Chen, Qi; Ji, Min; Pa, Mier; Qiao, Zhongwei [Children' s Hospital of Fudan University, Department of Radiology, Shanghai (China); Zhu, Hui [Fudan University Shanghai Cancer Center, Department of Radiology, Shanghai (China); Zheng, Shan [Children' s Hospital of Fudan University, Department of Surgery, Shanghai (China)

    2015-12-15

    The clinical presentation of congenital portosystemic shunt is variable and gastrointestinal bleeding is an uncommon presentation. To describe the imaging features of congenital portosystemic shunt as it presented in 11 children with (n = 6) and without gastrointestinal bleeding (n = 5). We performed a retrospective study on a clinical and imaging dataset of 11 children diagnosed with congenital portosystemic shunt. A total of 11 children with congenital portosystemic shunt were included in this study, 7 with extrahepatic portosystemic shunts and 4 with intrahepatic portosystemic shunts. Six patients with gastrointestinal bleeding had an extrahepatic portosystemic shunt, and the imaging results showed that the shunts originated from the splenomesenteric junction (n = 5) or splenic vein (n = 1) and connected to the internal iliac vein. Among the five cases of congenital portosystemic shunt without gastrointestinal bleeding, one case was an extrahepatic portosystemic shunt and the other four were intrahepatic portosystemic shunts. Most congenital portosystemic shunt patients with gastrointestinal bleeding had a shunt that drained portal blood into the iliac vein via an inferior mesenteric vein. This type of shunt was uncommon, but the concomitant rate of gastrointestinal bleeding with this type of shunt was high. (orig.)

  16. Studies on supratentorial subdural bleeding using a porcine model.

    Science.gov (United States)

    Zwetnow, N N; Orlin, J R; Wu, W H; Tajsic, N

    1993-01-01

    A porcine model for an acute lethal arterial subdural bleeding in man is presented. Blood from the abdominal aorta was led via an electronic drop recorder into a collapsed intracranial subdural rubber balloon. Systemic arterial pressure (SAP), two intracranial pressures and 6 other vital parameters were monitored continuously in spontaneously breathing (n = 4) and mechanically ventilated (n = 4) pigs. In both animal groups bleeding caused an immediate rise in intracranial pressures (ICP) with transtentorial pressure gradients developing. As a result the cerebral perfusion pressures (CPP) decreased progressively, leading to an isoelectric EEG. In spontaneously breathing animals, the pressure changes resulted in apnoea within 2-4 minutes, irregularities in heart rhythm and in a marked rise in SAP (the Cushing reaction). A final collapse of all pressures occurred after 222 +/- 68 sec at a mean bleeding volume of 10.3 +/- 1.9 ml. In contrast, in mechanically ventilated animals, the course of bleeding was less dramatic. No change in cardiac rhythm or rise in SAP appeared despite a larger mean bleeding volume (12.0 +/- 1.6 ml). Instead, SAP slowly fell, reaching a level of approximately 40 mm Hg within 1 hour, while CPP concomitantly decreased from 120 mm Hg to 15 mm Hg. The findings in this and in a parallel study are explained in terms of the intracranial volume tolerance concept (Zwetnow et al. 1986). The beneficial effect of assisted ventilation on the course of subdural bleeding is multifactorial, involving both metabolic and mechanical mechanisms. PMID:8475809

  17. Bleeding after endoscopic submucosal dissection: Risk factors and preventive methods

    Science.gov (United States)

    Kataoka, Yosuke; Tsuji, Yosuke; Sakaguchi, Yoshiki; Minatsuki, Chihiro; Asada-Hirayama, Itsuko; Niimi, Keiko; Ono, Satoshi; Kodashima, Shinya; Yamamichi, Nobutake; Fujishiro, Mitsuhiro; Koike, Kazuhiko

    2016-01-01

    Endoscopic submucosal dissection (ESD) has become widely accepted as a standard method of treatment for superficial gastrointestinal neoplasms because it enables en block resection even for large lesions or fibrotic lesions with minimal invasiveness, and decreases the local recurrence rate. Moreover, specimens resected in an en block fashion enable accurate histological assessment. Taking these factors into consideration, ESD seems to be more advantageous than conventional endoscopic mucosal resection (EMR), but the associated risks of perioperative adverse events are higher than in EMR. Bleeding after ESD is the most frequent among these adverse events. Although post-ESD bleeding can be controlled by endoscopic hemostasis in most cases, it may lead to serious conditions including hemorrhagic shock. Even with preventive methods including administration of acid secretion inhibitors and preventive hemostasis, post-ESD bleeding cannot be completely prevented. In addition high-risk cases for post-ESD bleeding, which include cases with the use of antithrombotic agents or which require large resection, are increasing. Although there have been many reports about associated risk factors and methods of preventing post-ESD bleeding, many issues remain unsolved. Therefore, in this review, we have overviewed risk factors and methods of preventing post-ESD bleeding from previous studies. Endoscopists should have sufficient knowledge of these risk factors and preventive methods when performing ESD.

  18. Transcatheter embolization for treatment of acute lower gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Treatment of lower gastrointestinal bleeding was attempted in 13 patients by selective embolization of branches of the mesenteric arteries with Gelfoam. Bleeding was adequately controlled in 11 patients with active bleeding during the examination. One patient improved after embolization but bleeding recurred within 24 hours and in another patient the catheterization was unsuccessful. Five patients with diverticular hemorrhage were embolized in the right colic artery four times, and once in the middle colic artery. Three patients had embolization of the ileocolic artery because of hemorrhage from cecal angiodysplasia, post appendectomy, and leukemia infiltration. Three patients had the superior hemorrhoidal artery embolized because of bleeding from unspecific proctitis, infiltration of the rectum from a carcinoma of the bladder, and transendoscopic polypectomy. One patient was septic and bled from jejunal ulcers. Ischemic changes with infarction of the large bowel developed in two patients and were treated by partial semi-elective colectomy, three and four days after embolization. Four other patients developed pain and fever after embolization. Transcatheter embolization of branches of mesenteric arteries in an effective way to control acute lower gastrointestinal bleeding, but still has a significant rate of complications that must be seriously weighed against the advantages of operation. (orig.)

  19. Multidetector computed tomography in acute lower gastrointestinal bleeding

    Directory of Open Access Journals (Sweden)

    John Palma

    2010-11-01

    Full Text Available John Palma, Marius Mihaila, Frank PilleulDépartement de Radiologie Digestive et des Urgences, Hôpital Edouard Herriot, Hospices Civils de Lyon, CHU, Lyon, FranceBackground: The aim of this study is to evaluate multidetector computed tomography (MDCT in acute massive lower gastrointestinal bleeding, with endoscopy and surgery as reference examinations.Methods: A single-center retrospective study involving 34 patients with acute massive lower gastrointestinal bleeding was carried out. All patients were evaluated by MDCT scan then endoscopic or surgical examinations. Sensitivity, specificity, and positive and negative predictive values of MDCT scan were calculated using the extravasation of the contrast agent as the main criterion.Results: Extravasation of the contrast agent was found in 30 of 34 patients (88%. The bleeding site seen on CT was always the same as on endoscopic or surgical examinations (100%. Sensitivity of MDCT scan was 94%, specificity 100%, positive predictive value 100%, and negative predictive value 50% (P < 0.001. Twelve diverticulum bleedings were seen on MDCT scan compared with 13 (92% on endoscopic or surgical examinations. Angiodysplasia was overestimated by MDCT scan.Conclusion: MDCT scan appears to be an excellent tool to find and localize the bleeding site in cases of acute massive lower gastrointestinal disease.Keywords: MDCT, acute lower gastrointestinal bleeding, extravasation, contrast agent

  20. 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

  1. 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

  2. Network level pavement evaluation with 1 mm 3D survey system

    Directory of Open Access Journals (Sweden)

    Kelvin C.P. Wang

    2015-12-01

    Full Text Available The latest iteration of PaveVision3D Ultra can obtain true 1 mm resolution 3D data at full-lane coverage in all 3 directions at highway speed up to 60 mph. This paper introduces the PaveVision3D Ultra technology for rapid network level pavement survey on approximately 1280 center miles of Oklahoma interstate highways. With sophisticated automated distress analyzer (ADA software interface, the collected 1 mm 3D data provide Oklahoma Department of Transportation (ODOT with comprehensive solutions for automated evaluation of pavement surface including longitudinal profile for roughness, transverse profile for rutting, predicted hydroplaning speed for safety analysis, and cracking and various surface defects for distresses. The pruned exact linear time (PELT method, an optimal partitioning algorithm, is implemented to identify change points and dynamically determine homogeneous segments so as to assist ODOT effectively using the available 1 mm 3D pavement surface condition data for decision-making. The application of 1 mm 3D laser imaging technology for network survey is unprecedented. This innovative technology allows highway agencies to access its options in using the 1 mm 3D system for its design and management purposes, particularly to meet the data needs for pavement management system (PMS, pavement ME design and highway performance monitoring system (HPMS.

  3. State-of-the-art review of the applications of nanotechnology in pavement materials

    Science.gov (United States)

    Castillo, Luis, Jr.

    The use of nanotechnology in pavement materials is one main area that shows great promise and has the potential to change commonly used materials. This will develop more effective solutions to achieve the desired performance. The overall objective of this work is to present a state-of-the-art literature review of nano-science-based principles to improve the performance and, ultimately, the life cycle of transportation construction materials. This work will be organized into two different parts. The first part will consist of six sections: applications of nanotechnology in concrete pavements, applications of nanotechnology in asphalt pavement, application of nanotechnology in general soils, cost-benefit analysis, challenges, and trends to the future. In addition, a current practice review was performed from a literature review that included a questionnaire of the knowledge and opinion about nanotechnology, which included students, general contractors, teachers, engineers, and architects. The second part will deal with the advancement of the application of nanotechnology in pavement materials for different developed countries. Because nanotechnology is relatively a young field in pavement materials, limited research has been conducted in North America, Europe, and Asia. A comparison of the advancement of nano-science-based principles, as applied to the performance and life cycle of transportation materials, for the three continents will be carried out in a summarized manner.

  4. Application of viscoelastic continuum damage approach to predict fatigue performance of Binzhou perpetual pavements

    Directory of Open Access Journals (Sweden)

    Wei Cao

    2016-04-01

    Full Text Available For this study, the Binzhou perpetual pavement test sections constructed in Shandong Province, China, were simulated for long-term fatigue performance using the layered viscoelastic pavement analysis for critical distresses (LVECD finite element software package. In this framework, asphalt concrete was treated in the context of linear viscoelastic continuum damage theory. A recently developed unified fatigue failure criterion that defined the boundaries of the applicable region of the theory was also incorporated. The mechanistic modeling of the fatigue mechanisms was able to accommodate the complex temperature variations and loading conditions of the field pavements in a rigorous manner. All of the material models were conveniently characterized by dynamic modulus tests and direct tension cyclic fatigue tests in the laboratory using cylindrical specimens. By comparing the obtained damage characteristic curves and failure criteria, it is found that mixtures with small aggregate particle sizes, a dense gradation, and modified asphalt binder tended to exhibit the best fatigue resistance at the material level. The 15-year finite element structural simulation results for all the test sections indicate that fatigue performance has a strong dependence on the thickness of the asphalt pavements. Based on the predicted location and severity of the fatigue damage, it is recommended that Sections 1 and 3 of the Binzhou test sections be employed for perpetual pavement design.

  5. PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States.

    Science.gov (United States)

    Van Metre, Peter C; Mahler, Barbara J; Wilson, Jennifer 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 SigmaPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SigmaPAH 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 dustfrom coal-tarsealcoated pavement and adjacent soils greatly exceed generic soil screening levels, suggesting that research on human-health risk is warranted. PMID:19209579

  6. PAHs underfoot: contaminated dust from coal-tar sealcoated pavement is widespread in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Peter C. Van Metre; Barbara J. Mahler; Jennifer T. Wilson [U.S. Geological Survey, Austin, TX (USA)

    2009-01-15

    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 {Sigma}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 SPAH concentrations in dust from sealcoated and unsealcoated pavement are 2200 and 27 mg/kg, respectively. For three western cities, median SPAH 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. 30 refs., 4 figs., 2 tabs.

  7. 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.

  8. 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.

  9. The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China.

    Science.gov (United States)

    Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

    2016-01-01

    This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO₂e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO₂e is 8215.31 tons. Based on the evaluation results, the CO₂e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO₂e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO₂e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO₂ in each phase, which accounts for more than 98% of total emissions. N₂O and CH₄ emissions are relatively insignificant. PMID:27347987

  10. 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.

  11. The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China

    Science.gov (United States)

    Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

    2016-01-01

    This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO2e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO2e is 8215.31 tons. Based on the evaluation results, the CO2e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO2e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO2e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO2 in each phase, which accounts for more than 98% of total emissions. N2O and CH4 emissions are relatively insignificant. PMID:27347987

  12. 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

  13. 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.

  14. The Greenhouse Gas Emission from Portland Cement Concrete Pavement Construction in China.

    Science.gov (United States)

    Ma, Feng; Sha, Aimin; Yang, Panpan; Huang, Yue

    2016-06-24

    This study proposes an inventory analysis method to evaluate the greenhouse gas (GHG) emissions from Portland cement concrete pavement construction, based on a case project in the west of China. The concrete pavement construction process was divided into three phases, namely raw material production, concrete manufacture and pavement onsite construction. The GHG emissions of the three phases are analyzed by a life cycle inventory method. The CO₂e is used to indicate the GHG emissions. The results show that for 1 km Portland cement concrete pavement construction, the total CO₂e is 8215.31 tons. Based on the evaluation results, the CO₂e of the raw material production phase is 7617.27 tons, accounting for 92.7% of the total GHG emissions; the CO₂e of the concrete manufacture phase is 598,033.10 kg, accounting for 7.2% of the total GHG emissions. Lastly, the CO₂e of the pavement onsite construction phase is 8396.59 kg, accounting for only 0.1% of the total GHG emissions. The main greenhouse gas is CO₂ in each phase, which accounts for more than 98% of total emissions. N₂O and CH₄ emissions are relatively insignificant.

  15. 公路路面扩宽中新老路面拼接的施工技术%Construction Technology of New and Old Pavement Splicing in Highway Pavement Widening

    Institute of Scientific and Technical Information of China (English)

    涂序广

    2014-01-01

    本文首先分析公路旧路面中存在的病害,然后分析在新旧路面拼接前对旧路面的处理,最后分析新老路面拼接施工技术在公路路面扩宽中的应用,供相关人员参考。%This paper firstly analyzes the existing diseases in old highway pavement, then analyzes the treatment of old pav-ement before the splicing of old and new pavement, final y an-alyzes the application of construction technology of new and old pavement splicing in highway pavement widening, to pro-vide a reference for the related personnel.

  16. 30 Years – 20 State DOTs: Trends in Pavement Management observed through real world Implementation at the State DOT Level

    OpenAIRE

    Zavitski, Jeffrey L.; Piane, Robert R.

    2013-01-01

    Since the first International Conference on Managing Pavement Assets 30 years ago in 1985, there has been continuous enhancement and evolution of pavement management system (PMS) technology to produce more effective recommendations coming out of an agency's PMS. Improvements in data collection, performance measures, deterioration modeling, dynamic segmentation, treatment algorithms, triggering mechanisms and optimization technologies have led to significant improvements in PMS strategy recomm...

  17. Evaluation of a new experimental test procedure to more accurately determine the surface infiltration rate of permeable pavement systems

    NARCIS (Netherlands)

    Lucke, T.; Boogaard, F.; Van den Ven, F.

    2014-01-01

    Permeable pavements are specifically designed to promote the infiltration of stormwater through the paving surface in order to reduce run-off volumes and to improve water quality by removing sediment and other pollutants. However, research has shown that permeable pavements can become clogged over t

  18. Analysing the accuracy of pavement performance models in the short and long terms: GMDH and ANFIS methods

    NARCIS (Netherlands)

    Ziari, H.; Sobhani, J.; Ayoubinejad, J.; Hartmann, T.

    2016-01-01

    The accuracy of pavement performance prediction is a critical part of pavement management and directly influences maintenance and rehabilitation strategies. Many models with various specifications have been proposed by researchers and used by agencies. This study presents nine variables affecting pa

  19. Mechanics based model for predicting structure-induced rolling resistance (SRR) of the tire-pavement system

    Science.gov (United States)

    Shakiba, Maryam; Ozer, Hasan; Ziyadi, Mojtaba; Al-Qadi, Imad L.

    2016-05-01

    The structure-induced rolling resistance of pavements, and its impact on vehicle fuel consumption, is investigated in this study. The structural response of pavement causes additional rolling resistance and fuel consumption of vehicles through deformation of pavement and various dissipation mechanisms associated with inelastic material properties and damping. Accurate and computationally efficient models are required to capture these mechanisms and obtain realistic estimates of changes in vehicle fuel consumption. Two mechanistic-based approaches are currently used to calculate vehicle fuel consumption as related to structural rolling resistance: dissipation-induced and deflection-induced methods. The deflection-induced approach is adopted in this study, and realistic representation of pavement-vehicle interactions (PVIs) is incorporated. In addition to considering viscoelastic behavior of asphalt concrete layers, the realistic representation of PVIs in this study includes non-uniform three-dimensional tire contact stresses and dynamic analysis in pavement simulations. The effects of analysis type, tire contact stresses, pavement viscoelastic properties, pavement damping coefficients, vehicle speed, and pavement temperature are then investigated.

  20. Prognostic variables in patients with cirrhosis and oesophageal varices without prior bleeding

    DEFF Research Database (Denmark)

    Møller, Søren; Bendtsen, Flemming; Christensen, E;

    1994-01-01

    As identification of patients at risk of bleeding or death is essential for prophylaxis, we determined the prognostic influence of various patient characteristics on the risk of bleeding and death. Fifty-five patients with cirrhosis and oesophageal varices without previous bleeding were included...... a significant relation with an increased risk of bleeding or death: high plasma volume (p varices (p

  1. Recycling of radioactive oil sludge waste into pavement brick

    International Nuclear Information System (INIS)

    Malaysia produces about 1450 tons of radioactive oil sludge waste per year and there is an urgent need to find a permanent solution to the storage and disposal of this radioactive waste problem. Several treatment methods such bacteria farming, ultracentrifuge, steam reforming and incineration are currently being used but the core issue of the radioactive material in the oil sludge had not been solved. The paper relates a study on utilizing the radioactive component of the oil sludge and turning them into pavement brick. Characteristic study of this radioactive component by XRD and XRF show that it mainly comprised of quartz and anorthite minerals. While the radioactivity analysis by gamma technique shows that more than 90 % of this radioactivity comes from this soil component with Ra-226 and Ra-228 as the main radionuclides. A vitrified brick was then produced from this sediment by mixing it with low radioactive local red clay. The result also shows that the formation of the vitrified layer may be due high content of K in the red clay. Tensile test on the brick shows that it has more than four times the strength of commercial clay brick. Long duration leaching test on the brick also shows that there is no dissolution of radionuclide from the brick. (author)

  2. Road roughness evaluation using in-pavement strain sensors

    Science.gov (United States)

    Zhang, Zhiming; Deng, Fodan; Huang, Ying; Bridgelall, Raj

    2015-11-01

    The international roughness index (IRI) is a characterization of road roughness or ride quality that transportation agencies most often report. The prevalent method of acquiring IRI data requires instrumented vehicles and technicians with specialized training to interpret the results. The extensive labor and high cost requirements associated with the existing approaches limit data collection to at most once per year for portions of the national highway system. Agencies characterize roughness only for some secondary roads but much less frequently, such as once every five years, resulting in outdated roughness information. This research developed a real-time roughness evaluation approach that links the output of durable in-pavement strain sensors to prevailing indices that summarize road roughness. Field experiments validated the high consistency of the approach by showing that it is within 3.3% of relative IRI estimates. After their installation and calibration during road construction, the ruggedized strain sensors will report road roughness continuously. Thus, the solution will provide agencies a real-time roughness monitoring solution over the remaining service life of road assets.

  3. Effects of conductive fillers on temperature distribution of asphalt pavements

    International Nuclear Information System (INIS)

    The sun provides a cheap and abundant source of clean and renewable energy. Solar cells have been used to capture this energy and generate electricity. A more useful form of the solar cell would be asphalt pavements, which get heated up by solar radiation. Graphite powders are utilized as thermal conductive fillers to make an asphalt collector conductive so as to improve the efficiency of the asphalt collector. Accounting for the important application conditions and evaluating the effects of the heat conductive materials and the solar energy absorbability of the conductive asphalt collector, a finite element model has been developed to predict temperature distributions in the conductive asphalt solar collector. In this study, an experimental validation exercise was conducted using the measured data taken from full-depth asphalt slabs. Validation results showed that the model can satisfactorily predict the temperature distributions in asphalt concrete slabs. The optimal depth is 25-50 mm for placing pipes that serve as the heat exchanger. Meanwhile, the effect of the surroundings on the solar energy potential of the asphalt collector was noticeable.

  4. Effects of conductive fillers on temperature distribution of asphalt pavements

    Science.gov (United States)

    Mingyu, Chen; Shaopeng, Wu; Yuan, Zhang; Hong, Wang

    2010-05-01

    The sun provides a cheap and abundant source of clean and renewable energy. Solar cells have been used to capture this energy and generate electricity. A more useful form of the solar cell would be asphalt pavements, which get heated up by solar radiation. Graphite powders are utilized as thermal conductive fillers to make an asphalt collector conductive so as to improve the efficiency of the asphalt collector. Accounting for the important application conditions and evaluating the effects of the heat conductive materials and the solar energy absorbability of the conductive asphalt collector, a finite element model has been developed to predict temperature distributions in the conductive asphalt solar collector. In this study, an experimental validation exercise was conducted using the measured data taken from full-depth asphalt slabs. Validation results showed that the model can satisfactorily predict the temperature distributions in asphalt concrete slabs. The optimal depth is 25-50 mm for placing pipes that serve as the heat exchanger. Meanwhile, the effect of the surroundings on the solar energy potential of the asphalt collector was noticeable.

  5. Road dust from pavement wear and traction sanding

    Energy Technology Data Exchange (ETDEWEB)

    Kupiainen, K.

    2007-07-01

    Vehicles affect the concentrations of ambient airborne particles through exhaust emissions, but particles are also formed in the mechanical processes in the tire-road interface, brakes, and engine. Particles deposited on or in the vicinity of the road may be re-entrained, or resuspended, into air through vehicle-induced turbulence and shearing stress of the tires. A commonly used term for these particles is 'road dust'. The processes affecting road dust emissions are complex and currently not well known. Road dust has been acknowledged as a dominant source of PM10 especially during spring in the sub-arctic urban areas, e.g. in Scandinavia, Finland, North America and Japan. The high proportion of road dust in sub-arctic regions of the world has been linked to the snowy winter conditions that make it necessary to use traction control methods. Traction control methods include dispersion of traction sand, melting of ice with brine solutions, and equipping the tires with either metal studs (studded winter tires), snow chains, or special tire design (friction tires). Several of these methods enhance the formation of mineral particles from pavement wear and/or from traction sand that accumulate in the road environment during winter. When snow and ice melt and surfaces dry out, traffic-induced turbulence makes some of the particles airborne. A general aim of this study was to study processes and factors underlying and affecting the formation and emissions of road dust from paved road surfaces. Special emphasis was placed on studying particle formation and sources during tire road interaction, especially when different applications of traction control, namely traction sanding and/or winter tires were in use. Respirable particles with aerodynamic diameter below 10 micrometers (PM10) have been the main concern, but other size ranges and particle size distributions were also studied. The following specific research questions were addressed: (i) How do traction

  6. Cytokinin signaling regulates pavement cell morphogenesis in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Hongjiang Li; Tongda Xu; Deshu Lin; Mingzhang Wen; Mingtang Xie; Jér(o)me Duclercq; Agnieszka Bielach

    2013-01-01

    The puzzle piece-shaped Arabidopsis leaf pavement cells (PCs) with interdigitated lobes and indents is a good model system to investigate the mechanisms that coordinate cell polarity and shape formation within a tissue.Auxin has been shown to coordinate the interdigitation by activating ROP GTPase-dependent signaling pathways.To identify additional components or mechanisms,we screened for mutants with abnormal PC morphogenesis and found that cytokinin signaling regulates the PC interdigitation pattern.Reduction in cytokinin accumulation and defects in cytokinin signaling (such as in ARR7-over-expressing lines,the ahk3cre1 cytokinin receptor mutant,and the ahp12345 cytokinin signaling mutant) enhanced PC interdigitation,whereas over-production of cytokinin and over-activation of cytokinin signaling in an ARR20 over-expression line delayed or abolished PC interdigitation throughout the cotyledon.Genetic and biochemical analyses suggest that cytokinin signaling acts upstream of ROPs to suppress the formation of interdigitated pattern.Our results provide novel mechanistic understanding of the pathways controlling PC shape and uncover a new role for cytokinin signaling in cell morphogenesis.

  7. 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

  8. 沥青路面施工技术浅谈%On construction technology of asphalt pavement

    Institute of Scientific and Technical Information of China (English)

    李伟勇

    2009-01-01

    Combined with wide application of asphalt pavement the reasons caused the premature failure of asphalt pavement axe analyzed, at the same time corresponding key points for asphalt pavement construction are presented. Meanwhile, technological research and innovation prospect of asphalt pavement are elaborated, in order to increase construction quality and prolong the service life of asphalt pavement to ensure investment benefits.%结合沥青路面的广泛应用,分析了沥青路面早期损害形成的原因,提出了沥青路面施工要领,阐述了沥青路面的技术研究和创新前景,以提高沥青路面的质量,延长沥青路面的使用周期,从而提高投资效益.

  9. Modelling of composite concrete block pavement systems applying a cohesive zone model

    DEFF Research Database (Denmark)

    Skar, Asmus; Poulsen, Peter Noe

    This paper presents a numerical analysis of the fracture behaviour of the cement bound base material in composite concrete block pavement systems, using a cohesive zone model. The functionality of the proposed model is tested on experimental and numerical investigations of beam bending tests...... that the cohesive model is suitable for simulation of crack propagation in cement bound materials subjected to monotonic loading. The methodology implemented gives a new understanding of the mechanical behaviour of cement bound materials which can be used in further refinements of mechanical models for composite...... block pavements. It is envisaged that the methodology implemented in this study can be extended and thereby contribute to the ongoing development of rational failure criteria that can replace the empirical formulas currently used in pavement engineering....

  10. 3-D cohesive finite element model for application in structural analysis of heavy duty composite pavements

    DEFF Research Database (Denmark)

    Skar, Asmus; Poulsen, Peter Noe

    2015-01-01

    The problem of stiffness degradation in composite pavement systems from localised fracture damage in the quasibrittle cement bound granular mixture are today taken into account only by empirical formulas. These formulas deals with a limited number of materials in a restricted range of design...... this paper presents a numerical analysis of the fracture behaviour of cement bound granular mixtures in composite concrete block pavement systems applying a cohesive model. The functionality of the proposed model is compared to experimental investigations of beam bending tests. The pavement is modelled...... as a slab on grade and parameters influencing the response such as geometry, material parameters and loading position are studied and compared to experimental results. It is found that a cohesive model is suitable for the description of the fracture behaviour of cement bound granular mixtures. Moreover...

  11. Monitoring the performance of geosynthetic materials within pavement systems using MEMS

    Science.gov (United States)

    Attoh-Okine, Nii O.; Ayenu-Prah, Albert Y.; Mensah, Stephen A.

    2005-05-01

    Geosynthetic materials have found useful applications when unbound aggregates have been placed on cohesive soil with very weak subgrade. They have also been successfully used in retarding reflective cracking in both flexible and composite pavements. There are many applications of geosynthetics in pavement engineering yet there is considerable lack of understanding in the behavior of the material. Geosynthetic materials exhibit very peculiar properties in the area of tensile strength and reinforcement. MEMS are miniature sensing or actuating devices that can interact with other environments (provided no adverse reaction occurs) to either obtain information or alter it. With remote query capability, it appears such devices can be embedded in pavement systems as testing and monitoring tools. The aim of this paper is to propose both field and laboratory methods for monitoring geotextile performance using MEMS.

  12. Research on segregation evaluation methods of asphalt pavement based on air voids distribution

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Eye observation was used to evaluate the segregation degree of asphalt pavement, which was not much creditable. To the asphalt pavement, road surface texture measuring method which has appeared recently can identify gradational segregation; but it can't reflect the influence of the temperature segregation. However,using infrared temperature detector to evaluate the segregation must be taken during paving, which brings much inconvenience. In this paper, measuring the air voids distribution using non-nuclear density gauge to evaluate asphalt pavement segregation was introduced. Result shows that this method can directly reflect the comprehensive results of the two types of segregation in a high efficient and accurate way. Moreover, using the sketch map of segregation area can help to analyze the segregation reason visually.

  13. Viscoroute 2.0: a tool for the simulation of moving load effects on asphalt pavement

    CERN Document Server

    Chabot, Armelle; Deloffre, Lydie; Duhamel, Denis

    2010-01-01

    As shown by strains measured on full scale experimental aircraft structures, traffic of slow-moving multiple loads leads to asymmetric transverse strains that can be higher than longitudinal strains at the bottom of asphalt pavement layers. To analyze this effect, a model and a software called ViscoRoute have been developed. In these tools, the structure is represented by a multilayered half-space, the thermo-viscoelastic behaviour of asphalt layers is accounted by the Huet-Sayegh rheological law and loads are assumed to move at constant speed. First, the paper presents a comparison of results obtained with ViscoRoute to results stemming from the specialized literature. For thick asphalt pavement and several configurations of moving loads, other ViscoRoute simulations confirm that it is necessary to incorporate viscoelastic effects in the modelling to well predict the pavement behaviour and to anticipate possible damages in the structure.

  14. New Technology and Experimental Study on Snow-Melting Heated Pavement System in Tunnel Portal

    Directory of Open Access Journals (Sweden)

    Jinxing Lai

    2015-01-01

    Full Text Available In recent years, with the rapid growth of economy and sharp rise of motor vehicles in China, the pavement skid resistance in tunnel portals has become increasingly important in cold region. However, the deicing salt, snow removal with machine, and other antiskid measures adopted by highway maintenance division have many limitations. To improve the treatment effect, we proposed a new snow-melting approach employing electric heat tracing, in which heating cables are installed in the structural layer of road. Through the field experiment, laboratory experiment, and numerical investigation, structure type, heating power, and preheating time of the flexible pavement heating system in tunnel portal were systematically analyzed, and advantages of electric heat tracing technology in improving the pavement skid resistance in tunnel portal were also presented. Therefore, such new technology, which offers new snow-melting methods for tunnel portal, bridge, mountainous area, and large longitudinal slope in cold region, has promising prospect for extensive application.

  15. Analysis of asphalt pavement structural response from an accelerated loading test

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study was to compare theoretical calculation and practical measurement structure response of asphalt pavement. Analysis of the pavement layer moduli was determined from a Back-calculation of Falling Weight Deflectometer (FWD) data and the measured stiffness moduli of asphalt layer cores. The pavement response was calculated using a theoretical model and the measured strain response at the bottom different layers.Layered elastic theory was used to back-calculate the layer moduli and three different theory models were used to forward calculate the strain and deflection. The models were: Layered Elastic Theory (LET), the Method of Equivalent Thicknesses (MET) with linear elastic and the Finite Element Method (FEM) where asphalt layer may be viscoelastic. The results showed that the calculation structure response from FEM was consistent with measured results.

  16. Plastic Damage Model to Evaluate the Fracture Size of Semi-Rigid Base Pavement

    Directory of Open Access Journals (Sweden)

    Cao Peng

    2013-01-01

    Full Text Available A simple supported beam model has been presented to simulate the response of semi-rigid pavement structure, which are consistent of the upper layer, middle layer, bottom layer, base and sub base course, during the cycle vehicle loading. This mechanics model coupled with plastic-damage mechanics model could simulate the limit broken of the pavement structure in condition that soil base layer losing bearing capacity gradually. In the meanwhile, numerical calculations based on preceding mechanics model, using the FEM software ABAQUS, have been used to define the broken size of beam. The results indicated that: when the size of simple supported beam expanded to 10 m, brittle damage could happen immediately, Just the standard vehicle loading (about 0.7 Mpa has been implement once. Objective of this study is to provide a physical and rather concrete explanation for the style and concept of the semi-rigid pavement brittle broken.

  17. Application of cluster analysis to preventive maintenance scheme design of pavement

    Institute of Scientific and Technical Information of China (English)

    ZENG Feng; ZHANG Xiao-ning

    2009-01-01

    To quantitatively identify the maintenance demand for each highway segments in the pavement main-tenance scheme design, a mathematical model of uniform segment division was established and an approach of applying cluster analysis theory to the uniform segment division and evaluation of pavement maintenance demand was proposed.The actual maintenance project of a highway carried out in Guangdong province was cited as an example to demonstrate the validity of the proposed method.It is proved that the cluster analysis can eliminate human factors in classification without being constrained by the quantities of samples, considering muhiple pavement distress indexes and the continuity of samples.Thus it is evident that cluster analysis is an efficient analytical tool in uniform segment division and evaluation of maintenance demand.

  18. 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 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)

  19. The Effect of Slope Geometry and Shoulder on Rutting Depth of Flexible Pavement

    Directory of Open Access Journals (Sweden)

    Mohammad Mehdi Khabiri

    2015-05-01

    Full Text Available The slope and width of the road shoulder are important parameters in geometry of the road pavement. Therefore, it is important to comply with the requirements relating to the slope and width of the shoulders. So that by using the minimum width and slope of the shoulders according to regulations not only stresses and strains transferred to the lower layers will decrease, but also reduces damages in asphalt layers, base, and sub-base. Therefore, it is vital to conduct analyses which can bring good amount of accuracy in assessment of the stress and settlement due to shoulder width and slope. The aim of this study is to investigate the effect of geometry of the shoulder on the performance and behavior of weak or strong pavement. For this purpose, numerical two-dimensional modeling of the road pavement (asphalt،base،sub-base on which the axel load is placed was done using finite element method, ABAQUS, and the effect of the shoulder width and slope on the stresses and settlements caused by the strong and weak pavement have been studied. Also for verification of the software, several obtained field values are compared to each other. The results indicate that the increase in the width of the shoulders and the decrease in the slope will cause in decrease of the stress and settlements in different layers of the roadways. Thus, creating less steeper shoulder and wider pavement can reduce damages and will contribute to the increased safety and sustained life of the pavement.

  20. How to transform an asphalt concrete pavement into a solar turbine

    International Nuclear Information System (INIS)

    Highlights: • We create a system for harvesting energy from asphalt concrete. • We create an artificial porosity in the asphalt concrete. • We connect a chimney to this porosity. • Differences in temperature produce an air flow. • This air flow serves also for cooling down the pavement. - Abstract: Asphalt concrete can absorb a considerable amount of the incident solar radiation. For this reason asphalt roads could be used as solar collectors. There have been different attempts to achieve this goal. All of them have been done by integrating pipes conducting liquid, through the structure of the asphalt concrete. The problem of this system is that all pipes need to be interconnected: if one is broken, the liquid will come out and damage the asphalt concrete. To overcome these limitations, in this article, an alternative concept is proposed:parallel air conduits, where air can circulate will be integrated in the pavement structure. The idea is to connect these artificial pore volumes in the pavement to an updraft or to a downdraft chimney. Differences of temperature between the pavement and the environment can be used to create an air flow, which would allow wind turbines to produce an amount of energy and that would cool the pavement down in summer or even warm it up in winter. To demonstrate that this is possible, an asphalt concrete prototype has been created and basics calculations on the parameters affecting the system have been done. It has been found that different temperatures, volumes of air inside the asphalt and the difference of temperature between the asphalt concrete and the environment are critical to maximize the air flow through the pavement. Moreover, it has been found that this system can be also used to reduce the heat island effect