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1

Predicting pavement distress in oil field areas  

Energy Technology Data Exchange (ETDEWEB)

A study on oil field traffic characteristics was performed and a procedure was developed for assessing current and future effects of oil field truck traffic on surface-treated (stage construction type) pavements. A computer program calculates several types of pavement distress and serviceability parameters to evaluate pavement performance under various axle load repetitions. Stepwise regression analysis of 132 surface-treated pavement sections led to the development of individual distress equations for rutting, raveling, flushing, alligator cracking, patching, longitudinal and transverse cracking, and failures (potholes). The versatility of the program provides a means of anticipating early pavement failures due to increased axle load repetitions. The program also provides the basic framework for computing the effects of other ''special-use'' truck traffic demands.

Mason, J.M.; Scullion, T.; Stampley, B.E.

1983-05-01

2

Predicting pavement distress in oil field areas  

Energy Technology Data Exchange (ETDEWEB)

A study on oil field traffic characteristics was performed and a procedure was developed for assessing current and future effects of oil field truck traffic on surface-treated (stage construction type) pavements. A computer program calculates several types of pavement distress and serviceability parameters to evaluate pavement performance under various axle load repetitions. Stepwise regression analysis of 132 surface-treated pavement sections led to the development of individual distress equations for rutting, raveling, flushing, alligator cracking, patching, longitudinal and transverse cracking, and failures (potholes). The versatility of the program provides a means of anticipating early pavement failures due to increased axle load repetitions. The program also provides the basic framework for computing the effects of other ''special-use'' truck traffic demands.

Mason, J.M.; Scullion, T.; Stampley, B.E.

1984-05-01

3

A Novel Pavement Distress Image Filtering Algorithm  

Directory of Open Access Journals (Sweden)

Full Text Available Combined the Nonsubsampled Contourlet Transform (NSCT) with compressed sensing de-noising theory, this study proposed a compressed sensing image filtering algorithm in the NSCT transform domain. This algorithm adopted the transform domain filtering method. Firstly, the NSCT was used to do multi-scale and multi-directional transform on the input noisy pavement distress Image which was mapped to the transform domain. Then the compressed sensing theory was used to filter the high-frequency sub-band coefficients. The experiment results show that this algorithm improves the effectiveness and timeliness of the pavement distress image filtering.

Shen Yu; Dang Jian-Wu; Feng Xin; Wang Yang-Ping

2013-01-01

4

Automated Survey of Pavement Distress based on 2D and 3D Laser Images.  

Science.gov (United States)

Despite numerous efforts in recent decades, currently most information on pavement surface distresses cannot be obtained automatically, at high-speed, and at acceptable precision and bias levels. This research provided seed funding to produce a functional...

K. Wang

2011-01-01

5

LDPE and CRMB Utilization in Bituminous Concrete Pavement Surfaces  

Directory of Open Access Journals (Sweden)

Full Text Available The road traffic and the traffic intensity are also increasing. Thus the load bearing capacities of the road is to be increased. There are two types of roads - flexible pavements (bitumen roads) and rigid pavements (concrete roads). Flexible pavements (bitumen roads) comprise of the major portion of all surfaced roads. In India, bituminous surfaced flexible pavements comprise of majority of the roads. Distress symptoms, such as cracking, rutting, etc., are being increasingly caused earlier by high traffic intensity, over loading of vehicles and significant variations in daily and seasonal temperature of the pavement. Investigations have revealed that modifiers can be used to improve rheological properties of bitumen and bituminous mixes to make it more suitable for road construction. Bituminous-mix design involves mixing various aggregate sizes and bitumen contents in optimum proportions. For a given aggregate gradation, the optimum bitumen content is estimated by satisfying a number of mix design parameters. Badly compacted bituminous mixtures develop low stiffness, bad fatigue resistance, bad durability, etc. which are undesirable characteristics for a good pavement. Modified Bitumen is one of the important construction materials for flexible pavements. Use of plastic waste (LDPE) and Crumb Rubber in the construction of flexible pavement is gaining importance. The modified bitumen show better properties for road construction.

Payal Bakshi

2013-01-01

6

Laser-Based 3D Data Acquisition System for the Analysis of Pavement Distress and Roughness.  

Science.gov (United States)

In this report we deal with the detection and classification of pavement cracks. Currently, ConnDOT is using Wisecrax which is a commercial product supplied by Roadware. We develop a 3D laser based technique to detect the cracks in a certain pavement sect...

B. Javidi D. Kim S. Kishk

2004-01-01

7

Pavement cracking measurements using 3D laser-scan images  

Science.gov (United States)

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

Ouyang, W.; Xu, B.

2013-10-01

8

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

Science.gov (United States)

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

9

Pavement Evaluation Concepts Using Nondestructive Structural Evaluation and Pavement Condition Index.  

Science.gov (United States)

A logical method for pavement evaluation utilizing both nondestructive procedures for structural analysis and pavement condition distress to identify maintenance needs is presented. Alternatives for maintaining desired serviceability are categorized as ro...

J. W. Hall

1987-01-01

10

A Physically-based Model for Surface and Subsurface Drainage from Porous Pavement Overlays  

Science.gov (United States)

A thin layer of porous asphalt is commonly overlain on regular impermeable pavement to reduce splash and spray and improve visibility in wet weather. The porous layer often has a large hydraulic conductivity (>1cm/s) to encourage infiltration and drainage and therefore contains runoff when the rainfall intensity is low. However, under high rainfall intensity, the layer’s capacity is exceeded and drainage occurs both within and on top of the porous pavement. The problem is analogous to hill-slope hydrology of a thin aquifer where infiltration occurs rapidly and sheet flow is generated only when the aquifer is full. Common roadway features such as slope transitions and curvature make the drainage two-dimensional. A computer model was developed to study this coupled, unsteady process. The porous layer is modeled using the Boussinesq equation. The diffusion wave model is used for sheet flow over the pavement surface. This presentation summarizes the model’s development, shows that model results compare favorably to field measurements, and gives a case study in which the porous layer reduces the maximum sheet flow depth by 25% compared to conventional pavement.

Eck, B. J.; Barrett, M.; Charbeneau, R. J.

2010-12-01

11

Distress and rehabilitation method of airport concrete pavements. Kuko concrete hoso no henjo to hoshu hokyo hoho  

Energy Technology Data Exchange (ETDEWEB)

This paper summarizes methods to evaluate deformation of airport concrete pavements and introduces major repair methods. Airports carry out periodical investigations from daily checks to full scale investigations. Especially the road condition investigations performed every three years make evaluations using an index called a pavement rehabilitation index (PRI) that quantifies the conditions based on crack lengths/areas, joint damage lengths, and steps. (Airports in the U.S.A. use not only these three items, but 15 items of damage conditions to calculate the PCI.) Repair methods are determined according to these values. As a pavement structural evaluation method, a non-destructive evaluation method is proposed that uses a ball-dropping bend measurement. Elasticity coefficients, road bed bearing capacity, and existence of clearance are estimated from the bend measurement. Types of pavement damages are as various as blow-up, crack, patching, pop-out, etc. Based on the evaluation results, the necessity of repair and construction methods are determined, such as filler injection, patching, re-concreting, and overlay. 6 refs., 6 figs., 2 tabs.

Hachiya, Y. (Port and Harbour Research Institute, Kanagawa (Japan))

1993-07-01

12

Surface recycle system of asphalt pavement. Asphalt hoso no surface recycle system  

Energy Technology Data Exchange (ETDEWEB)

The surface recycle method of asphalt pavement is a construction method to heat and regenerate the surface for the purpose of reforming the road profile and the quality of asphalt mixtures damaged by wheels. The present report explains the progress, technique, apparatuses, achievements, etc. in this method. The construction is performed following the sequence of heating of the surface, scratching and disentangling, mixing, smoothing and solidifying. In this case, three methods of reform, repave and remix are used depending on not using new material, laying and spreading it, or mixing new and old material for restoration respectively. Actually the latter two are mainly employed. Road heating is performed by using a mobile truck mounted with a combustor of LPG or kerosine. Although function improvement such as miniaturization of machines, automation of remote control by radio, etc. are being advanced, there still remain some problems. Considering enhancement of importance of this method from the viewpoint of reducing construction materials, further advancement may be required to obtain systemized and improved technology. 3 refs., 5 figs.

Inagaki, T. (Seikitokyu Kogyo Co. Ltd., Tokyo (Japan))

1994-03-25

13

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

Directory of Open Access Journals (Sweden)

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

SARAT, Adebayo-Aminu; EUSUF, Muhammad Abu

2012-01-01

14

Pavement management  

Energy Technology Data Exchange (ETDEWEB)

The 11 papers in this report deal with the following areas: effect of pavement roughness on vehicle fuel consumption; rational seasonal load restrictions and overload permits; state-level pavement monitoring program; data requirements for long-term monitoring of pavements as a basis for development of multiple regression relations; simplified pavement management at the network level; combined priority programming of maintenance and rehabilitation for pavement networks; Arizona pavement management system: Phase 2-verification of performance prediction models and development of data base; overview of paver pavement management system; economic analysis of field implementation of paver pavement management system; development of a statewide pavement maintenance management system; and, prediction of pavement maintenance expenditure by using a statistical cost function.

Ross, F.R.; Connor, B.; Lytton, R.L.; Darter, M.I.; Shahin, M.Y.

1982-01-01

15

Material Selection and Design Consideration for Moisture Damage of Asphalt Pavement.  

Science.gov (United States)

Moisture damage is a primary mode of distress occurring in Nebraska hot mix asphalt (HMA) pavements. The use of hydrated lime has been recommended for Nebraska HMA pavements to mitigate moisture-related damage. There are several techniques of introducing ...

J. E. S. Lutif Y. Kim

2006-01-01

16

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

Directory of Open Access Journals (Sweden)

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

Tienfuan Kerh; Yu-Min Wang; Yulern Lin

2005-01-01

17

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.

18

Pavement-management system for concrete roadways in Virginia. Phase 1. Condition ratings. Final report  

Energy Technology Data Exchange (ETDEWEB)

The report traces the development of a rating system for evaluating the service condition of Virginia's portland-cement concrete pavements. The service condition is assessed in terms of distress roughness, i.e., that portion of a pavement's poor-ride characteristics directly attributable to the occurrence of certain key distress types. Field surveys of the occurrence of these distresses provide the necessary data for estimating distress roughness through the use of prediction equations that have been established from the standard statistical analysis of pavement-section distress data and roughness measurements. Distress measurements and their corresponding ratings and a condition survey rating procedure are appended.

Long, R.R.

1988-04-01

19

Permeable Pavement  

Science.gov (United States)

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

Integrated Teaching And Learning Program

20

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

Science.gov (United States)

Permeable pavements and similar stormwater control devices have not been exploited in the UK, in part because their adoption has been hindered by a lack of detailed knowledge of their hydrological performance. This paper describes a research programme that produced detailed information on the hydrological behaviour of a car park surface. The study involved the construction of full-scale permeable pavement model car park structures and a rainfall simulator for use in the laboratory. A monitoring procedure was developed in order to measure inputs and changes in drainage, storage and evaporation over short and long time-scales (2 hours to 3 months). A range of simulated rainfalls, which varied in intensity and duration, was applied to the model car park surfaces. Hydrological processes were monitored over an 18-month period. Results demonstrated that evaporation, drainage and retention in the structures were strongly influenced by the particle size distribution of the bedding material and by water retention in the surface blocks. In general, an average of 55% of a one-hour duration, 15 mm h-1 rainfall event could be retained by an initially air-dry structure. Subsequent simulations demonstrated that 30% of a one-hour duration, 15 mm h-1 rainfall event could be stored by an initially wet structure (with a minimum time interval between rainfall applications of 72 hours).

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

1999-03-01

 
 
 
 
21

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

International Nuclear Information System (INIS)

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

2003-01-01

22

Asphalt Rubber Concrete Pavement. User's Guide.  

Science.gov (United States)

Asphalt rubber concrete pavements include at least two types of flexible pavement surfacings made with asphalt rubber cement as the binder, stone mastic and open-graded mixtures. The asphalt rubber binder generally contains 15-25 percent recycled scrap ti...

G. L. Anderton

1994-01-01

23

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

Directory of Open Access Journals (Sweden)

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

Khabiry Mehdi; Gourbian Nader

2009-01-01

24

[Particle numbers in classified sizes of roadside dust caused by studded tires in the air at different heights from the pavement surface].  

UK PubMed Central (United Kingdom)

Increased use of motor vehicles has produced various risks to human health due to air pollution by noxious gases, heavy metals and roadside dust. Since the late 1970s, the wide spread use of studded tires for cars has caused pavement wear, resulting in not only economic losses, but also roadside air pollution in cold and snowy regions in Japan. The most serious environmental problem in Sapporo, a city with heavy snowfall, in the 1980s, was roadside dust derived from studded tires. The inhabitants suffered from this dust in the early winter and in the early spring when the streets were not covered with snow. To investigate the influence of such roadside dust upon human health, particle numbers in classified sizes of roadside dust were counted after the roadside dust in the air was collected with a device we constructed at 30, 60, 90, 120, 150, and 180 cm above the pavement surface. The results indicated that the concentration of roadside dust in the air did not greatly vary according to the height from the pavement surface. The results also suggested that xenogranuloma, reported in lungs of stray dogs, under roadside dust-pollution conditions such as those examined here, may occur in humans in the future.

Sato T; Niioka T; Kurasaki M; Kojima Y

1996-07-01

25

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. ...

26

STATUS OF POROUS PAVEMENT RESEARCH  

Science.gov (United States)

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

27

Hybrid green permeable pave with hexagonal modular pavement systems  

Science.gov (United States)

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.

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

2013-06-01

28

Fracture of highway and airport pavements  

Science.gov (United States)

Existing solutions for the stresses in a cracked slab containing a crack and supported by an elastic foundation are extended to obtain the stress intensity factor (SIF) for a crack in a pavement subjected to moving vehicular loads. In the existing solutions the stresses can be obtained only for a uniform bending stress (before the crack occurs) along the crack surface. For pavements subjected to moving vehicular loads, the stress distribution along the crack surface is not uniform and the approximation of a uniform stress is often unsatisfactory. The present work extends the above solutions to cover more realistic loading of highway and airport pavements. This facilitates the application of the principles of fracture mechanics to the fatigue crack propagation and fracture of pavements. Beginning with a part-through semi-elliptical starter crack, the crack is assumed to grow under load and the SIF is presented at various stages of crack growth, from the starter crack into a short through-crack that eventually becomes a very long through-crack. Some examples of the fracture of typical rigid and flexible highway and airport pavements are presented to show the need to consider fracture in the design of pavements.

Ramsamooj, D. V.

1993-03-01

29

Runway Operability under Cold Weather Conditions. Tire-pavement friction creation by sand particles on iced pavements, and non-contacting detection of sand particles on pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Airports that operate under cold weather conditions face major challenges in ensuring that runways, taxiways and aprons provide sufficient tire-pavement friction to the operating aircraft. This thesis is motivated by two practical problems: (1) maintaining or improving the pavement surface condition...

Klein-Paste, Alex

30

Vehicle dynamic response due to pavement roughness  

Directory of Open Access Journals (Sweden)

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

Roberto Spinola Barbosa

2011-01-01

31

Asphalt in Pavement Maintenance.  

Science.gov (United States)

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…

Asphalt Inst., College Park, MD.

32

Effect Of Geopathic Stress On Bituminous Pavement  

Directory of Open Access Journals (Sweden)

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

B.H.CHAFEKAR; G.P.JARAD; S.S.PIMPLIKAR; A.G.KHARAT; N.P.DHARMADHIKARI; R.R.SORATE

2013-01-01

33

Modeling the Pavement Present Serviceability Index of Flexible Highway Pavements Using Data Mining  

Directory of Open Access Journals (Sweden)

Full Text Available The term present serviceability was adopted to represent the momentary ability of pavement to serve traffic and the performance of the pavement was represented by its serviceability history in conjunction with its load application history. Serviceability was found to be influenced by longitudinal and transverse profile as well as the extent of cracking and patching. The amount of weight to assign to each element in the determination of the over-all serviceability is a matter of subjective opinion. In the present study, a regression tree model has been presented for determining flexible pavement surface layer thickness. The model, RT was selected as estimating method. Results show that wearing course thickness of flexible pavement regression values of the regression tree model is better than that of the AASHO model. This approach can be easily and realistically performed to solve the optimization problems which do not have a formulation or function about the solution.

Serdal Terzi

2006-01-01

34

Field Evaluation of Nondestructive Tests in Measuring the Pavement Layers Density  

Directory of Open Access Journals (Sweden)

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

H. Ziari; H. Behbahani; A. Izadi; H. Divandary

2010-01-01

35

Pervious Pavement System Evaluation  

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, grade...

36

Pavement Patching Guidelines.  

Science.gov (United States)

This report presents guidelines for pavement patching. 'How to-do-it' recommendations are presented for constructing patches during cold weather (emergency basis), cold weather (routine basis), and warm weather (routine basis). Patching of flexible, rigid...

K. Majidzadeh M. S. Luther

1983-01-01

37

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

Directory of Open Access Journals (Sweden)

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

Jitendra Gurjar, Pradeep Kumar Agarwal, Manoj Kumar Sharma

2013-01-01

38

Effect of training algorithms on neural networks aided pavement diagnosis  

Directory of Open Access Journals (Sweden)

Full Text Available Routine pavement maintenance necessitates present structural diagnosis and condition evaluation of pavements by employing non-destructive test equipment such as the Falling Weight Deflectometer (FWD). FWD testing of pavements involves measuring time-domain surface deflections resulting from applied impulse loading on the pavement. Through inverse analysis of FWD deflection data, the stiffness parameters of the individual pavement layers are, in general, determined using iterative optimization routines. In recent years, Neural Networks (NN) aided inverse analysis has emerged as a successful alternative for predicting pavement layer moduli from FWD deflection data in real-time. Especially, the use of Finite Element (FE) based pavement modeling results for training the NN aided inverse analysis is considered to be accurate in realistically characterizing the non-linear stress-sensitive response of underlying pavement layers in real-time. Efficient NN learning algorithms have been developed and proposed to determine the weights of the network, according to the data of the computational task to be performed. In this paper, the effect of training algorithms on the NN aided inversion process is analyzed and discussed.

Kasthurirangan Gopalakrishnan

2010-01-01

39

Structural design of airport concrete pavement on soft ground with differential settlement. Jiban no fudo chinka wo koryoshita kuko concrete hoso no kozo sekkei  

Energy Technology Data Exchange (ETDEWEB)

Pavement may be divided into asphalt pavement and concrete pavement and the concrete pavement centered at apron is relatively often used in airport because it has good bearing capacity. The present paper, taking apron pavement in of offing expansion project district of Tokyo International Airport as an example, treats the structural design of no-reinforcing steel airport concrete pavement on soft ground with differential settlement. At first, the ground characteristics of the expansion district of Tokyo International Airport are discussed and then the effects of the ground characteristics on the concrete pavement in case the slope on pavement surface deviates from standard value and in case the pavement is destroyed by gaps between the concrete layer and road base are studied. At last, the structural design of airport concrete pavement on the soft ground is examined. 15 refs. , 14 figs., 3 tabs.

Soda, S. (Ministry of Transport, Tokyo (Japan)); Hachiya, Y. (Port and Harbour Research Inst., Tokyo (Japan))

1992-08-20

40

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

Scientific Electronic Library Online (English)

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

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

1999-09-01

 
 
 
 
41

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

Scientific Electronic Library Online (English)

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

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

2012-09-01

42

Pavement Snow Melting  

Energy Technology Data Exchange (ETDEWEB)

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

Lund, John W.

2005-01-01

43

Use of lug anchors to related pavement movement  

Science.gov (United States)

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

Oakey, S. A.

1980-04-01

44

Asphalt for draining pavement; Haisuisei hosoyo asphalt  

Energy Technology Data Exchange (ETDEWEB)

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.

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

1994-12-28

45

POROUS PAVEMENT: RESEARCH; DEVELOPMENT; AND DEMONSTRATION  

Science.gov (United States)

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

46

Roughness Progression on KDOT Asphalt Pavements.  

Science.gov (United States)

Pavement smoothness is a major factor affecting performance. Since the introduction of the Superpave system in Kansas, bonus payment for asphalt pavement construction has increased significantly, indicating that these pavements are smoother initially. How...

J. Mulandi Z. Siddique M. Hossain P. I. Nelson

2007-01-01

47

Long-term stormwater quantity and quality performance of permeable pavement systems.  

Science.gov (United States)

This study examined the long-term effectiveness of permeable pavement as an alternative to traditional impervious asphalt pavement in a parking area. Four commercially available permeable pavement systems were evaluated after 6 years of daily parking usage for structural durability, ability to infiltrate precipitation, and impacts on infiltrate water quality. All four permeable pavement systems showed no major signs of wear. Virtually all rainwater infiltrated through the permeable pavements, with almost no surface runoff. The infiltrated water had significantly lower levels of copper and zinc than the direct surface runoff from the asphalt area. Motor oil was detected in 89% of samples from the asphalt runoff but not in any water sample infiltrated through the permeable pavement. Neither lead nor diesel fuel were detected in any sample. Infiltrate measured 5 years earlier displayed significantly higher concentrations of zinc and significantly lower concentrations of copper and lead. PMID:14511707

Brattebo, Benjamin O; Booth, Derek B

2003-11-01

48

Long-term stormwater quantity and quality performance of permeable pavement systems.  

UK PubMed Central (United Kingdom)

This study examined the long-term effectiveness of permeable pavement as an alternative to traditional impervious asphalt pavement in a parking area. Four commercially available permeable pavement systems were evaluated after 6 years of daily parking usage for structural durability, ability to infiltrate precipitation, and impacts on infiltrate water quality. All four permeable pavement systems showed no major signs of wear. Virtually all rainwater infiltrated through the permeable pavements, with almost no surface runoff. The infiltrated water had significantly lower levels of copper and zinc than the direct surface runoff from the asphalt area. Motor oil was detected in 89% of samples from the asphalt runoff but not in any water sample infiltrated through the permeable pavement. Neither lead nor diesel fuel were detected in any sample. Infiltrate measured 5 years earlier displayed significantly higher concentrations of zinc and significantly lower concentrations of copper and lead.

Brattebo BO; Booth DB

2003-11-01

49

Influence of pavement condition on horizontal curve safety.  

UK PubMed Central (United Kingdom)

Crash statistics suggest that horizontal curves are the most vulnerable sites for crash occurrence. These crashes are often severe and many involve at least some level of injury due to the nature of the collisions. Ensuring the desired pavement surface condition is one potentially effective strategy to reduce the occurrence of severe accidents on horizontal curves. This study sought to develop crash injury severity models by integrating crash and pavement surface condition databases. It focuses on developing a causal relationship between pavement condition indices and severity level of crashes occurring on two-lane horizontal curves in Texas. In addition, it examines the suitability of the existing Skid Index for safety maintenance of two-lane curves. Significant correlation is evident between pavement condition and crash injury severity on two-lane undivided horizontal curves in Texas. Probability of a crash becoming fatal is appreciably sensitive to certain pavement indices. Data suggested that road facilities providing a smoother and more comfortable ride are vulnerable to severe crashes on horizontal curves. In addition, the study found that longitudinal skid measurement barely correlates with injury severity of crashes occurring on curved portions. The study recommends exploring the option of incorporating lateral friction measurement into Pavement Management System (PMS) databases specifically at curved road segments.

Buddhavarapu P; Banerjee A; Prozzi JA

2013-03-01

50

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

Science.gov (United States)

This study determines whether environment-protecting pervious pavement can dilute pollutants immediately after emissions from vehicle. The turbulence-driven dry-deposition process is too slow to be considered in this aspect. The pavement used is the JW pavement (according to its inventors name), a high-load-bearing water-permeable pavement with patents in over 100 countries, which has already been used for more than 8 years in Taiwan and is well suited to replacing conventional road pavement, making the potential implementation of the study results feasible. The design of this study included two sets of experiments. Variation of the air pollutant concentrations within a fenced area over the JW pavement with one vehicle discharging emissions into was monitored and compared with results over a non-JW pavement. The ambient wind speed was low during the first experiment, and the results obtained were highly credible. It was found that the JW pavement diluted vehicle pollutant emissions near the ground surface by 40%-87% within 5 min of emission; whereas the data at 2 m height suggested that about 58%-97% of pollutants were trapped underneath the pavement 20 min after emission. Those quantitative estimations may be off by +/- 10%, if errors in emissions and measurements were considered. SO2 and CO2 underwent the most significant reduction. Very likely, pollutants were forced to move underneath due to the special design of the pavement. During the second experiment, ambient wind speeds were high and the results obtained had less credibility, but they did not disprove the pollutant dilution capacity of the JW pavement. In order to track the fate of pollutants, parts of the pavement were removed to reveal a micro version of wetland underneath, which could possibly hold the responsibility of absorbing and decomposing pollutants to forms harmless to the environment and human health. PMID:22393814

Liu, Chung-Ming; Chen, Jui-Wen; Tsai, Jen-Hui; Lin, Wei-Shian; Yen, M-T; Chen, Ting-Hao

2012-01-01

51

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

UK PubMed Central (United Kingdom)

This study determines whether environment-protecting pervious pavement can dilute pollutants immediately after emissions from vehicle. The turbulence-driven dry-deposition process is too slow to be considered in this aspect. The pavement used is the JW pavement (according to its inventors name), a high-load-bearing water-permeable pavement with patents in over 100 countries, which has already been used for more than 8 years in Taiwan and is well suited to replacing conventional road pavement, making the potential implementation of the study results feasible. The design of this study included two sets of experiments. Variation of the air pollutant concentrations within a fenced area over the JW pavement with one vehicle discharging emissions into was monitored and compared with results over a non-JW pavement. The ambient wind speed was low during the first experiment, and the results obtained were highly credible. It was found that the JW pavement diluted vehicle pollutant emissions near the ground surface by 40%-87% within 5 min of emission; whereas the data at 2 m height suggested that about 58%-97% of pollutants were trapped underneath the pavement 20 min after emission. Those quantitative estimations may be off by +/- 10%, if errors in emissions and measurements were considered. SO2 and CO2 underwent the most significant reduction. Very likely, pollutants were forced to move underneath due to the special design of the pavement. During the second experiment, ambient wind speeds were high and the results obtained had less credibility, but they did not disprove the pollutant dilution capacity of the JW pavement. In order to track the fate of pollutants, parts of the pavement were removed to reveal a micro version of wetland underneath, which could possibly hold the responsibility of absorbing and decomposing pollutants to forms harmless to the environment and human health.

Liu CM; Chen JW; Tsai JH; Lin WS; Yen MT; Chen TH

2012-01-01

52

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

DEFF Research Database (Denmark)

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

Zhang, Wei; Ullidtz, Per

1998-01-01

53

Influence of pavement macrotexture on PM10 emissions from paved roads: A controlled study  

Science.gov (United States)

This paper investigates influence of pavement macrotexture on paved road PM10 emissions. This study was conducted on different paved roadway types (local, collector and minor arterial) in the Las Vegas Valley, Nevada. Pavement macrotexture was measured using the ASTM E 965 sand patch method and the Digital Surface Roughness Meter™ (DSRM™). A controlled constant soil loading with known PM10 fraction was applied to cleaned road surfaces. The Desert Research Institute's (DRI) Mini-PI-SWERL™ (Portable In-Situ Wind ERosion Lab) was used to estimate PM10 mass emissions and cumulative mass emitted from pavement surfaces. PM10 mass emissions using controlled applied soil loadings generally declined with increasing pavement macrotexture at all applied shear levels. The relationships were statistically significant, and indicate that pavement macrotexture may need to be included in future development of revised paved road PM10 emissions factors.A change in the slope of emitted PM10 mass and pavement macrotexture occurred between 0.8 and 0.9 mm mean texture depth (MTD). Anomalies in PM10 mass emissions were observed at MTDs exceeding 1.2 mm. Two-way frequency distributions of pavement surface features obtained from DSRM measurements were analyzed to explain the observed anomalies. Results showed that pavement surface feature size distributions may influence on PM10 emissions from paved roads at similar MTDs.PM10 mass emissions were found to linearly depend on adjusted mode size of the pavement surface aggregate. A sharp decrease in friction velocities, computed from wind erosion theory, at MTDs above 0.9 mm matched an observed sharp decrease in PM10 emissions rates at MTDs above 0.9 mm, indicating that classical wind erosion theory could be adapted for non-erodible pavement surfaces and linearly relate PM10 emissions rates to applied shear stress at an aerodynamic roughness height of 0.075 mm.

China, Swarup; James, David E.

2012-12-01

54

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...

55

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...

56

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...

57

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...

58

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

Directory of Open Access Journals (Sweden)

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

Arvind Dewangan; , Dr.D.P. Gupta, Dr. R.K.Bakshi

2012-01-01

59

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

Directory of Open Access Journals (Sweden)

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.

Saurabh Jain

2013-01-01

60

Distress management.  

UK PubMed Central (United Kingdom)

The integration of psychosocial care into the routine care of all patients with cancer is increasingly being recognized as the new standard of care. These NCCN Clinical Practice Guidelines in Oncology for Distress Management discuss the identification and treatment of psychosocial problems in patients with cancer. They are intended to assist oncology teams identify patients who require referral to psychosocial resources and to give oncology teams guidance on interventions for patients with mild distress to ensure that all patients with distress are recognized and treated.

Holland JC; Andersen B; Breitbart WS; Buchmann LO; Compas B; Deshields TL; Dudley MM; Fleishman S; Fulcher CD; Greenberg DB; Greiner CB; Handzo GF; Hoofring L; Hoover C; Jacobsen PB; Kvale E; Levy MH; Loscalzo MJ; McAllister-Black R; Mechanic KY; Palesh O; Pazar JP; Riba MB; Roper K; Valentine AD; Wagner LI; Zevon MA; McMillian NR; Freedman-Cass DA

2013-02-01

 
 
 
 
61

Structural Design of Pavements for Light Aircraft.  

Science.gov (United States)

This report presents structural design criteria for airfield pavements to be used by light aircraft; i.e., those with gross weights less than 30,000 lb. Presented are criteria for conventional flexible and rigid pavements, for rigid and flexible pavements...

D. M. Ladd F. Parker A. T. Pereira

1976-01-01

62

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...

63

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

Directory of Open Access Journals (Sweden)

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.

Adebayo Oladipo Owolabi; Obanishola Mufutau Sadiq; Oladapo Samson Abiola

2012-01-01

64

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

Science.gov (United States)

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

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

2010-10-01

65

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

66

Manganese pavements on the blake plateau.  

UK PubMed Central (United Kingdom)

Dredge samples and photographs from the Blake Plateau, off the southeast coast of the United States, indicate that a layer of manganese oxide forms pavement that may be continuous over an area af about 5000 square kilometers. The manganese pavement grades into round manganese nodules to the south and east and into phosphate nodules to the west. The Gulf Stream probably maintains a very unusual environment that prohibits deposition of clastic sediment and permits accretion of manganese pavements.

Pratt RM; McFarlin PF

1966-03-01

67

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

UK PubMed Central (United Kingdom)

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.

Li H; Kayhanian M; Harvey JT

2013-03-01

68

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

Science.gov (United States)

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

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

2013-02-21

69

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2001-11-21

70

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, which we call the chipping and aggregate methods, and calculated their potential life cycle costs. By analyzing the potential for increased pavement durability resulting from these conceptual approaches, we then estimated the incremental costs that would allow them to be cost-effective compared to conventional AC. For our example case of Los Angeles, we found that those allowable incremental costs range from less than dollar 1 to more than dollar 11 per square yard (dollar 1 to dollar 13 per square meter) depending on street type and the condition of the original pavement. Finally, we evaluated the main actors in the pavement market and the existing and potential market barriers associated with reflective pavements. Apart from situations where lifecycle costs are high compared to conventional AC, all reflective paving technologies face a cultural barrier based on the belief that black is better. For PCC, high first costs were found to be the most significant economic barrier, particularly where agencies are cons trained by first cost. Lack of developer standards was found to be a significant institutional barrier to PCC since developers are often not held accountable for the long-term maintenance of roads after initial construction, which creates a misplaced incentive to build low first-cost pavements. PCC also faces site-specific barriers such as poorly compacted base soils and proximity to areas of frequent utility cutting.

2001-01-01

71

Review of permeable pavement systems  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this review paper is to summarise the wide-range but diffuse literature on predominantly permeable pavement systems (PPS), highlight current trends in research and industry, and to recommend future areas of research and development. The development of PPS as an integral part of sustainable drainage systems is reviewed in the context of traditional and modern urban drainage. Particular emphasise is given to detailed design, maintenance and water quality control aspects. The most important target pollutants are hydrocarbons, heavy metals and nutrients (i.e. nitrogen and phosphorus). The advantages and disadvantages of different PPS are discussed with the help of recent case studies. The latest innovations are highlighted and explained, and their potential for further research work is outlined. Recent research on the development of a combined geothermal heating and cooling, water treatment, and recycling pavement system is promising. (author)

Scholz, Miklas; Grabowiecki, Piotr [Institute for Infrastructure and Environment, School of Engineering and Electronics, The University of Edinburgh, William Rankine Building, The King' s Buildings, Edinburgh EH9 3JL, Scotland (United Kingdom)

2007-11-15

72

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

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

73

Mathematical failure-theory (MFT) methodology in pavement management system for rehabilitation and repair methods selection  

Directory of Open Access Journals (Sweden)

Full Text Available Pavement rehabilitation and repair methods selection is one of the key issues many road organizations and researchers have occupied. Not only road management cost but also road user’s cost and cost for inhabitants and community should be included in the life cycle cost in order to help infrastructure investment judgment. Thus in estimating life cycle cost, Pavement rehabilitation and repair methods selection is essential even if technological capabilities of evaluation are not sufficient. In order for Pavement Management Systems (PMS) to be effective, they must be based on a reliable, statistically sound means for the rehabilitation and repair methods that are present on the system. To make sensible life cycle cost decisions in design and rehabilitation, pavement engineers must be able to account for distress phenomena and repair methods. This paper will present a Mathematical Failure-Theory (MFT) methodology for incorporating statistical and probabilistically Factors into life cycle cost analysis and PMS. This approach gives the engineer the ability to statistically and probability consider different rehabilitation and repair method and statistically and probability factors in computing the life cycle costs for rehabilitation and repair methods selection.

Fereidoon Moghadas Nejad; Hasan Ziari; Ameri Mahmod

2009-01-01

74

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...

75

Porous Pavement for Control of Highway Runoff.  

Science.gov (United States)

A three-lane by 3500 linear feet portion of an urban highway was constructed of porous pavement. The design resulted from a research study of the use of porous pavement to provide highway drainage. It was determined that after two years of observation, th...

W. R. Meier E. Elnicky

1989-01-01

76

Recycling of Asphalt Pavements with Asphalt Rubber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

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

77

Recycling of asphalt pavements with asphalt rubber  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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...

Pais, Jorge C.; Pereira, Paulo A. A.; Minhoto, Manuel J. C.; Baptista, António

78

EDGE RESTRAINT FOR WATER PERMEABLE PAVEMENT SYSTEMS  

UK PubMed Central (United Kingdom)

A T-shaped edge restraint for use in water permeable pavement systems. The base (stem) of the T has a plurality of openings to facilitate the use of spikes or anchors or to facilitate curving the edge restraint to accommodate curved sections of the pavement system.

ZWIER DANIEL G; ANDERSON ROBERT D

79

Analysis and design optimization of flexible pavement  

Energy Technology Data Exchange (ETDEWEB)

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.

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

2000-04-01

80

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

Scientific Electronic Library Online (English)

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

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

2009-03-01

 
 
 
 
81

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

Directory of Open Access Journals (Sweden)

Full Text Available This paper describes a fast procedure for evaluating asphalt pavement surface defects using airborne emissivity data. To develop this procedure, we used airborne multispectral emissivity data covering an urban test area close to Venice (Italy).For this study, we first identify and select the roads’ asphalt pavements on Multispectral Infrared Visible Imaging Spectrometer (MIVIS) imagery using a segmentation procedure. Next, since in asphalt pavements the surface defects are strictly related to the decrease of oily components that cause an increase of the abundance of surfacing limestone, the diagnostic absorption emissivity peak at 11.2μm of the limestone was used for retrieving from MIVIS emissivity data the areas exhibiting defects on asphalt pavements surface.The results showed that MIVIS emissivity allows establishing a threshold that points out those asphalt road sites on which a check for a maintenance intervention is required. Therefore, this technique can supply local government authorities an efficient, rapid and repeatable road mapping procedure providing the location of the asphalt pavements to be checked.

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

2008-01-01

82

Measurement of pavement macrotexture through digital image processing  

Directory of Open Access Journals (Sweden)

Full Text Available The texture data of roads and airport pavement are extremely important for reducing accidents, mainly in cases of wet surface. The texture measurement is essential to evaluate the driving quality, however the conventional processes (field tests) are expensive and cause traffic interruption.   The aim of the present study was to develop a practical procedure to measure the asphalt pavement macrotexture using image processing and to compare it with sand patch tests. The parameter selected to quantify the surface pavement condition was the image information content calculated by a FFT (Fast Fourier Transform) through modification in the light intensity among neighboring pixels, this modification is called spatial frequency. Seeking to contribute with traditional methods, the proposed procedure causes low interruption in traffic, being also fast, accurate, with good reproducibility, and low cost. In comparison with sand patch test, the image processing technique proved to be efficient, and suitable to be used to identify areas with texture problem, reducing the possibility of accidents.  

Luciano Pivoto Specht; Oleg Khatchatourian; Reginaldo Tudéia dos Santos

2013-01-01

83

Respiratory Distress Syndrome  

Science.gov (United States)

... page from the NHLBI on Twitter. What Is Respiratory Distress Syndrome? Respiratory distress syndrome (RDS) is a breathing disorder that ... BPD; blindness; and brain damage. Rate This Content: Respiratory Distress Syndrome Clinical Trials Clinical trials are research ...

84

Global warming potential of pavements  

International Nuclear Information System (INIS)

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

2009-01-01

85

Nonlinear Responses of a Two Dimensional Vehicle-pavement System  

Directory of Open Access Journals (Sweden)

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.

Shaohua Li; Haoyu Li

2013-01-01

86

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...

87

Airfield Pavement Condition Survey, Usnas Lemoore, California.  

Science.gov (United States)

The results of a condition survey of the airfield pavements at the U. S. Naval Air Station, Lemoore, California is presented. The survey established statistically-based condition numbers (weighted defect densities) which were direct indicators of the cond...

D. J. Lambiotte L. J. Woloszynski

1970-01-01

88

The Edison Environmental Center Permeable Pavement Site  

Science.gov (United States)

This a presentation for a Community Outreach Event called "Chemistry Works and Celebration of International Year of Chemistry." It will review the permeable pavement research project at the Edison Environmental center....

89

Statistical Acceptance Plan for Asphalt Pavement Construction.  

Science.gov (United States)

This report documents the development of statistical acceptance procedures for asphalt pavement construction. These acceptance procedures are recommended as modifications to the current U.S. Army Corps of Engineers (USACE) Guide Specifications entitled 'A...

R. B. Freeman W. P. Grogan

1998-01-01

90

Degradation Modeling of Polyurea Pavement Markings.  

Science.gov (United States)

Polyurea is a long life pavement marking material used for assets requiring long periods of uninterrupted accessibility. Knowing the performance characteristics of such markings is critical to asset management planning focused on maximizing marking materi...

J. D. Needham

2011-01-01

91

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

UK PubMed Central (United Kingdom)

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.

Junwei Z; Jinping L; Xiaojuan Q

2013-01-01

92

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

Science.gov (United States)

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

Junwei, Zhang; Jinping, Li; Xiaojuan, Quan

2013-08-20

93

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

Science.gov (United States)

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.

Jinping, Li; Xiaojuan, Quan

2013-01-01

94

Effects of tire-pavement contact pressure distributions on the response of asphalt concrete pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A computer program VIEM has been developed for the elastic analysis of multilayered elastic pavements under the action of arbitrary tire-pavement contact pressure distributions. VIEM involves the use of a two-dimensional numerical integration to integrate point load solutions over the distributed pr...

Yue, Zhong Qi; Svec, Otto J

95

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tire-pavement contact stress is traditionally assumed to be uniformly distributed over a circular contact area. In this study, the tire-pavement contact pressure has been modeled to be nonuniform. A new tire model is developed for the analysis based on the geometry of the tire footprint because the ...

M.H. Nahi; A. Ismail; A.K. Ariffin

96

Electrical resistance tomography for imaging the spatial distribution of moisture in pavement sections  

Energy Technology Data Exchange (ETDEWEB)

Electrical Resistance Tomography (ERT) was used to image spatial moisture distribution and movement in pavement sections during an infiltration test. ERT is a technique for determining the electrical resistivity distribution within a volume from measurement of injected currents and the resulting electrical potential distribution on the surface. The transfer resistance (ratio of potential to injected current) data are inverted using an algorithm based on a finite element forward solution which is iteratively adjusted in a least squares sense until the measured and calculated transfer resistances agree to within some predetermined value. Four arrays of ERT electrodes were installed in vertical drill holes 1.22 m (4 ft) placed at the comers of a square 61 cm (2 ft) on a side into a pavement section which is used for a truck scale ramp on U.S. Highway 99 just north of Sacramento, CA. Water was introduced slowly into the pavement through a shallow hole in the center of this pattern and ERT data were collected in various planes as the water infiltrated into the pavement and subgrade materials over a period of several hours. The ERT data were inverted, and the resulting images show (1) the basic structure of the pavement section and (2) the movement of water through the image planes as a function of time during infiltration. An interesting result is that the water does not appear to drain from the section toward the shoulder as had been expected based on the design.

Buettner, M.; Ramirez, A.; Daily, W.

1995-11-08

97

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

UK PubMed Central (United Kingdom)

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.

Starke P; Göbel P; Coldewey WG

2011-01-01

98

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

Science.gov (United States)

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

Starke, P; Göbel, P; Coldewey, W G

2011-01-01

99

POROUS PAVEMENT. PHASE I. DESIGN AND OPERATIONAL CRITERIA  

Science.gov (United States)

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

100

The effect of loading conditions on pavement responses calculated using a linear-elastic model  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In most structural pavement design methods, strains and stresses in the layers are calculated with multi-layer programs based on the Burmister model using the linear elastic theory. Burmister defined loads as a constant pressure applied on a circular surface. New technology for measuring t...

Perret, J.

 
 
 
 
101

Acute respiratory distress syndrome  

Science.gov (United States)

Acute respiratory distress syndrome (ARDS) is a life-threatening lung condition that prevents enough oxygen from getting to the lungs and into the blood. See also: Infant respiratory distress syndrome

102

Porous pavement. Phase 1: Design and operational criteria  

Science.gov (United States)

Utilization concepts, benefits and disadvantages, as well as other characteristics of porous pavements are presented with emphasis on porous asphalt pavements, but the criteria and design approach are applicable to all other porous pavement types. Design considerations include siting problems, load bearing design and hydrologic design. The history of porous pavement development and previous experience with porous pavement by several designers, contractors and operators are described. A computer model for hydrologic performance evaluation of existing or proposed porous pavement systems is also examined. Load bearing design criteria are based on previous work conducted for porous asphalt pavements. Appendices include a sample set of specifications for porous asphalt construction and a list of soils and their permeability classes as prepared by the U.S. Soil Conservation Service.

Diniz, E. V.

1980-08-01

103

Asphalt overlay design methods for rigid pavements considering rutting, reflection cracking, and fatigue cracking. Research report September 1996--August 1997  

Energy Technology Data Exchange (ETDEWEB)

An asphalt concrete pavement (ACP) overlay over a rigid pavement represents a viable rehabilitation strategy. It can provide good serviceability at an initial construction cost that is substantially less than that of a rigid overlay rehabilitation. In addition, ACP overlays require less construction time, which can reduce user costs during construction. However, it may not be the most economical solution for long-term rehabilitation. Because of their relatively short service life, ACP overlays may require maintenance sooner than rigid overlays. And one of the more critical distresses that effectively determine the life span of the structure is reflection cracking. This report investigates alternative strategies that seek to prevent reflection cracking on ACP overlays.

Cho, Y.H.; Liu, C.; Dossey, T.; McCullough, B.F.

1998-10-01

104

Experimental study on steel fiber-reinforced porous-cement concrete pavement. Kosen'i de hokyoshita tosuisei concrete hoso ni kansuru jikkenteki kenkyu  

Energy Technology Data Exchange (ETDEWEB)

It is being elucidated that the permeable pavement may provide the environmentally effective measure in the over populated cities. The permeable pavement has many problems like the durability is low and the blinding occurs, compared with the surface course material of the usual asphalt pavement. Accordingly, its application is limited to the pedestrian walks and the pavement making the relatively light vehicle as an object. In order to try to apply the permeable pavement to the vehicle traffic road, the authors have investigated the pavement materials focussing on them. The materials were seeked for the cement concrete for that purpose, and the steel fiber reinforced concrete composites were obtained. From the examination results of the rain runoff depression measure and the prediction of the rainfoall model depression effect by the permeable pavement of this materials, the depression effects of 15 % at the peak flow rate and 15 % at the total flow quantity can be expected. In addition it was found that the reinforced permeable concrete is superior in bending strength and durability, compared with the permeable plain concrete and can be applied to the vehicle road (heavy traffic quanitity). 9 refs., 12 figs., 9 tabs.

Nakamura, J. (Yokohama Sewage Works Bureau, Yokohama (Japan)); Miura, Y. (Nippon Univ., Tokyo (Japan). College of Science and Technology)

1992-09-20

105

Permeable pavement research â?? 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...

106

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

Science.gov (United States)

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

107

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

Science.gov (United States)

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

Ruhala, Richard James

1999-12-01

108

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

Directory of Open Access Journals (Sweden)

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

M.H. Nahi; A. Ismail; A.K. Ariffin

2011-01-01

109

The distress premium puzzle  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fama and French (1992) suggest that the positive value premium results from risk of financial distress. However, recent empirical research has found that financially distressed firms have lower stock returns, using empirical estimates of default probabilities. This paper reconciles the positive valu...

Ozdagli, Ali K.

110

Comparison Between 2-D and 3-D Stiffness Matrix Model Simulation of Sasw Inversion for Pavement Structure  

Directory of Open Access Journals (Sweden)

Full Text Available The Spectral Analysis of Surface Wave (SASW) method is a non-destructive in situ seismic technique used to assess and evaluate the material stiffness (dynamic elastic modulus) and thickness of pavement layers at low strains. These values can be used analytically to calculate load capacities in order to predict the performance of pavement system. The SASW method is based on the dispersion phenomena of Rayleigh waves in layered media. In order to get the actual shear wave velocities, 2-D and 3-D models are used in the simulation of the inversion process for best fitting between theoretical and empirical dispersion curves. The objective of this study is to simulate and compare the 2-D and 3-D model of SASW analysis in the construction of the theoretical dispersion curve for pavement structure evaluation. The result showed that the dispersion curve from the 3-D model was similar with the dispersion curve of the actual pavement profile compared to the 2-D model. The wave velocity profiles also showed that the 3-D model used in the SASW analysis is able to detect all the distinct layers of flexible pavement units.

Sri Atmaja P. Rosidi

2007-01-01

111

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2009-08-28

112

Small-scale accelerated pavement testing  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the results of a study conducted to explore the use of small-scale models of accelerated pavement testing (APT) devices to evaluate the performance of pavements in conjunction with full-scale tests. The motivation for the study was the availability of a model mobile load simulator (MMLS), which had been built originally to illustrate the operation of the full-scale mobile load simulator (MLS) under design at the time. The scaling requirements will be different depending on whether dynamic (inertia), viscous, or gravity effects are important. One must thus decide which one of these effects controls the behavior to try to reproduce it exactly. In the preliminary tests conducted with the MMLS, emphasis had been placed in reproducing accurately the viscoelastic behavior of the asphalt layer. The possibility of obtaining valid results, even if similitude is not maintained in relation to inertia forces, is explored in this paper. The effects of load frequency or velocity and the effects of layer thicknesses are studied. The total thickness of the model pavement, which must be finite, and its effects on displacements and strains are also considered. It is concluded that even when full similitude is not satisfied it is possible to obtain valid results that can be extrapolated to predict prototype performance if one were interested primarily in the behavior of the asphalt layer. Preliminary analyses should be conducted, however, to guide on the selection of the model dimensions.

Kim, S.M. [Korea Highway Corp., Kyunggi (Korea, Republic of). Highway Research Inst.; Hugo, F. [Univ. of Stellenbosch (South Africa). Inst. for Transport Technology; Roesset, J.M. [Univ. of Texas, Austin, TX (United States). Dept. of Civil Engineering

1998-03-01

113

Materials characterization of recycled asphalt concrete pavements  

Energy Technology Data Exchange (ETDEWEB)

The purpose of this study is to develop a data bank system for recycled asphalt concrete pavements and to evaluate the detailed engineering properties of recycled materials by means of an extensive laboratory investigation. The study first concentrates on developing a data bank system for recycled pavements. The data bank is intended to objectively identify and organize the past and present records, concerning the material characteristics, design, construction, cost, maintenance, and performance of recycled asphalt concrete projects. The data bank system assists in the long term study of recycled pavements performance. The primary goal of this study was to evaluate the detailed engineering properties of the recycled asphalt concrete materials and to compare these properties with those of the conventional materials. To achieve this, a testing program was designed, necessary experimental equipment developed, and a series of tests conducted on various binders and mixtures. The Marshall Stability, durability, nomograph stiffness, low temperature tensile properties, permanent deformation, and resilient modulus of various recycled and conventional mixtures were determined.

Hadipour, K.

1987-01-01

114

Design of a sensor for asphalt pavement pressure field measurements  

Science.gov (United States)

From the sensitivity of the FBG center wavelength changing with strain changes on the surface, the design of a FBG strain-based asphalt pavement pressure sensor is described by designing a special FBG asphalt box-film packaging structure. The compactness and simplicity of the device are achieved by using the corresponding package obtained from common available asphalt. Numerical analysis and experimental results show that the response of the sensor has good regularity for a wide range of travel (0MPa to 5.3312MPa). In the load range, the FBG center wavelength increases from 1548.264nm to 1548.346nm which shows a good correspondence with loads. Linearity, travel and sensitivity are experimentally determined by different packaging parameters. A design chart that includes the travel (0MPa to 5.3312MPa) and the sensitivity (15.3812pm/MPa) is finally proposed.

Liu, Hongyue; Liang, Dakai; Han, Xiaolin; Wang, Xiaogang

2013-06-01

115

Feasibility of crumb rubber use for asphalt pavement construction in Rhode Island. Final research report  

Energy Technology Data Exchange (ETDEWEB)

This is the final report of the research project, entitled `Viable Use of Crumb Rubber for Highway Construction in Rhode Island.` This study dealt with the investigation of the means by which the State of Rhode Island can effectively comply with the mandate of the Section 1038 of the 1991 Intermodal Surface Transportation Efficiency Act (ISTEA) to use recycled rubber in asphalt pavements. More specifically, this laboratory investigation characterized Hot Mix Asphalt (HMA) with Crumb Rubber Modifiers (CRM).

Lee, K.W.; Kovacs, W.D.; Marcus, A.S.; Madapati, R.R.

1995-12-15

116

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

International Nuclear Information System (INIS)

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

2011-01-01

117

Sorptivity-Based Service Life Predictions For Concrete Pavements  

UK PubMed Central (United Kingdom)

The degradation of concrete pavements is often controlled by the transport of a deleteriousspecies (chloride or sulfate ions, or water in the case of freeze/thaw) into the concrete. With thisin mind, a three-year research project, funded by the Federal Highway Administration, hasculminated in the development of sorptivity-based service life models for concrete pavementsand bridge decks. To develop a service life model, one needs to identify and model thesuspected degradation mechanism, develop laboratory tests to evaluate the critical materialproperties, and adequately characterize the exposure environment. For this project, degradationmechanisms for sulfate attack (ettringite-induced expansion) and freeze/thaw degradation(critical saturation of the air void system) have been postulated. To evaluate sorptivity, alaboratory-based testing protocol for conditioning and assessing the sorption properties of fieldconcrete cores has been developed and submitted to ASTM committee C09 for standardization.To characterize the exposure environment, a one-dimensional finite difference computer modelwhich utilizes typical meteorological year weather data supplied by the National RenewableEnergy Laboratory has been developed to predict the concrete pavement surface temperature andtime-of-wetness history for a wide variety of geographical locations throughout the UnitedStates. Finally, these methods and computational tools have been integrated into a computersoftware package, CONCLIFE, which provides sorptivity-based service life predictions.NOMENCLATUREt = time (s)A = surface area (m2)CE = concentration of reacted sulfate as ettringite (mol/m3)E = Young's modulus (GPa)I = sorption coefficient (m/s1/2)I 0 = initial sorption (m)W = mass gain (kg)X sp...

Dale P. Bentz; Mark A. Ehlen; Chiara F. Ferraris; Edward J. Garboczi

118

Performance of asphalt pavements at Bibi new test road; Bibi shinshiken doro ni okeru asphalt hoso no performance ni kansuru kenkyu  

Energy Technology Data Exchange (ETDEWEB)

Pavement performance evaluation method is presented in which the bearing capacity, which is one of the pavement performance elements, is treated as the scale of structural propriety, and the 50kN reduced deficient number recorded up to the generation of fatigue cracks is regarded as the life of the pavement. Furthermore, a fixed-period monitoring of the road surface damage and bearing capacity has been under way using the Bibi New Test Road since five years ago, and it has attained a cumulative equivalent dual wheel load of approximately 6.51-million wheels. The result of the research leads to a proposition for using the structural propriety index, in view of the asphalt mixture layer fatigue failure frequency and the cumulative equivalent dual wheel load up to the present time, as a pavement bearing capacity index. A performance degradation curve can be draw using the structural propriety index values for each of the pavement structures, and the correlation coefficients that they exhibit upon exponential regression are all 0.9 or higher. This means that the use of the structural propriety index allows the reasonable implementation of pavement maintenance and repair programs. Performance degradation curves are obtained of maintenance control indexes with the correlation coefficients not lower than 0.9. 24 refs., 10 figs., 7 tabs.

Ishitani, M.; Nakagawa, S.; Takahashi, M.; Ogasawara, A.; Kasahara, A.

1997-05-20

119

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

Scientific Electronic Library Online (English)

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

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

2012-08-01

120

Effects of traffic loading on portuguese and brazilian pavements performance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This work investigated the effects of traffic loading on the performance of Portuguese and Brazilian pavements, aiming to contribute to a better technical regulation of heavy vehicles and cost allocation related to the pavement deterioration. Among the traffic loading factors, this work considered a...

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

 
 
 
 
121

Full-Depth Asphalt Pavements for Parking Lots and Driveways.  

Science.gov (United States)

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,…

Asphalt Inst., College Park, MD.

122

Permeable Pavement Monitoring at the Edison Environmental Center Demonstration Site  

Science.gov (United States)

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

123

Permeable pavement demonstration site at Edison Environmental Center (Presentation)  

Science.gov (United States)

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

124

Permeable Pavement Research at the Edison Environmental Center  

Science.gov (United States)

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

125

Permeable Pavement Demonstration at the Edison Environmental Center (Hartford)  

Science.gov (United States)

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

126

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

Science.gov (United States)

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

127

Permeable pavement demonstration at the Edison Environmental Center  

Science.gov (United States)

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

128

Pervious Concrete: New Era For Rural Road Pavement  

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

129

Evaluation of flexible pavement performance life in Florida. Final research report, October 1993--June 1998  

Energy Technology Data Exchange (ETDEWEB)

The pavement performance life provides information on how long a particular pavement type will typically last before it needs rehabilitation. This study presents the research effort to estimate the average flexible pavement performance life in Florida. Two data files of Pavement Condition Survey (PCS) and Work Program Administration (WPA) were used for this study. SAS programs were applied to analyze and manipulate these two data files. The pavement performance condition curves were developed for a large sample size of pavement sections based on the polynomial model. The average pavement performance lives were evaluated for each pavement group based on the performance curves. The results of the evaluation showed that the primary system had longer average performance life than the interstate system. Generally, the polynomial model performed well in fitting the data. The pavement performance curve indicates that if M and R are performed while the pavement is still in the `slow rate of deterioration` phase, life cycle cost may be reduced.

Ping, W.V.; He, Y.

1998-06-01

130

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

UK PubMed Central (United Kingdom)

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

Coleri E; Kayhanian M; Harvey JT; Yang K; Boone JM

2013-08-01

131

Potential for energy savings in pavement rehabilitation  

Energy Technology Data Exchange (ETDEWEB)

Since the 1973 oil crisis, many organizations and government departments have examined the energy requirements associated with roads and transport in order to identify possible ways to conserve energy. The paper shows that, although the energy used in processing, haulage, and construction is important, the competitive market system will tend to ensure that energy use is minimized. It further shows that the energy cost of using new or recycled materials is one of many factors to be taken into account in the decision to recycle pavement materials and that its importance, therefore, should not be over-emphasized.

Servas, V.P.; Walker, R.N.

1986-01-01

132

An Innovative Strategy for Maintenance of Highway Pavement  

Directory of Open Access Journals (Sweden)

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.

Sandeep Choudhary, Dr. P. K. Agarwal

2013-01-01

133

Repair of the epoch-making concrete pavement. / The airport public corporation; Kakkitekina konkurito hoso no hoshu / kukokodan  

Energy Technology Data Exchange (ETDEWEB)

New Tokyo International Airport (Narita Air-port) meets for 20 years since the open port, and the time which requires the repair of various facilities is going to be met. The connected reinforced concrete pavement in apron division used for the 20 years without doing the until now real repair, though the load of the aircraft (about 400 t per machine) which enlarged year by year was supported and is put on, and the necessity of the repair occurs recently, and the method has been examined. In the inside, the increase of the environment consciousness in the up-date was received, and in the simple method, the generation of large concrete masses, etc. became a problem. Therefore, the examination on 'the adhesion type concrete overlay method' which newly places the concrete on the conventional pavement slab has been advanced in New Tokyo International Airport Authority. The adhesive strength of new and old both becomes a problem, because the new pavement in this method on conventional pavement slab is conducted. Bar arrangements are doings in order to solve this, when the gouging processing by shot blasting which gave the small ruggedness to aggregate surface which exposed by this with water jet which removes mortar minute of the concrete matter surface on the surface of pavement slab as a backing was conducted. The result of placing the concrete (the admixture ingredient use in low heat and normal Portland cement variously) for the overlay developed in the same public corporation at the 15 cm thickness. Though the repair of constructions of section about 35000 m{sup 2} constructed at present is kept by February, 1999, it calls the method repairing the vastitude Narita Air-port in the main afterwards too. (translated by NEDO)

NONE

1998-10-10

134

Binder for color pavement; Color hosoyo binder  

Energy Technology Data Exchange (ETDEWEB)

Resin bright color binder manufactured by Fuji Kosan Co., Ltd. which can be applied to color pavement by heating and uniform laying was introduced. This product is a light yellow - dark green binder which is adjusted to a penetration of 60/80 and 80/100 obtained by the refining process of oil with oil resin as a base. It shows a general property identical to that of straight asphalt and the resistance against deformation, fragility at a low temperature, and rheology property such as flow behavior at a high temperature are also similar. In the color asphalt pavement, the difference in tint caused by the thermal history after mixing a compound material and execution technique, functional advantage and disadvantage due to compaction strength, the difference in durability etc. may occur. The test result revealed that it was important to control the temperature of a heated mixture and to adjust retention time from the plant to an execution location to prevent hue difference. 9 refs., 5 figs., 7 tabs.

Onishi, K. [Fuji Kosan Co. Ltd., Tokyo (Japan)

1994-12-28

135

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

Science.gov (United States)

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

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

2009-01-01

136

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

UK PubMed Central (United Kingdom)

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

Myers BR; Beecham S; van Leeuwen JA; Keegan A

2009-01-01

137

Road dust from pavement wear and traction sanding  

Energy Technology Data Exchange (ETDEWEB)

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 sanding and physical properties of the traction sand aggregate affect formation of road dust (ii) How do studded tires affect the formation of road dust when compared with friction tires (iii) What are the composition and sources of airborne road dust in a road simulator and during a springtime road dust episode in Finland (iv) What is the size distribution of abrasion particles from tire-road interaction. The studies were conducted both in a road simulator and in field conditions. The test results from the road simulator showed that traction sanding increased road dust emissions, and that the effect became more dominant with increasing sand load. A high percentage of fine-grained anti-skid aggregate of overall grading increased the PM10 concentrations. Anti-skid aggregate with poor resistance to fragmentation resulted in higher PM levels compared with the other aggregates, and the effect became more significant with higher aggregate loads. Glaciofluvial aggregates tended to cause higher particle concentrations than crushed rocks with good fragmentation resistance. Comparison of tire types showed that studded tires result in higher formation of PM emissions compared with friction tires. The same trend between the tires was present in the tests with and without anti-skid aggregate. This finding applies to test conditions of the road simulator with negligible resuspension. Source and composition analysis showed that the particles in the road simulator were mainly minerals and originated from both traction sand and pavement aggregates. A clear contribution of particles from anti-skid aggregate to ambient PM and dust deposition was also observed in urban conditions. The road simulator results showed that the interaction between tires, anti-skid aggregate and road surface is important in dust production and the relative contributions of these sources depend on their properties. Traction sand grains are fragmented into smaller particles under the tires, but they also wear the pavement aggregate. Therefore particles from both aggregates are observed. The mass size distribut

Kupiainen, K.

2007-07-01

138

Prediction of Hydroplaning Potential from Runoff Characteristics of Highway Pavements.  

Science.gov (United States)

A computer program, HYDROP, was developed to predict hydroplaning potential resulting from uniform rainfall of any intensity on sections of highway pavement with varying degrees of topographic irregularity. The program uses a kinematic-wave approximation ...

J. R. Reed D. F. Kibler R. S. Heubner G. W. Marks

1985-01-01

139

Oil bio-degradation in permeable pavements by microbial communities.  

Science.gov (United States)

This paper reports on continuing research at Coventry University into the improvement of highway water quality following flow through a permeable pavement. Such pavements have been shown elsewhere to be efficient in-situ bio-reactors, capable of degrading large quantities of clean motor oil. Further laboratory research, reported here, demonstrates that a commercially obtained oil degrading, microbial mixture was not significantly better at degrading clean motor oil than the indigenous microbial biomass established within the pavement over a 4-year period, when provided with an adequate nutrient supply. Scanning electron microscopy has been used to monitor biofilm development, which has also identified that the pavement has developed a complex community structure with high bio-diversity. PMID:11989892

Newman, A P; Pratt, C J; Coupe, S J; Cresswell, N

2002-01-01

140

Permeable Pavement Demonstration at the Edison Environmental Center - Poster  

Science.gov (United States)

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

 
 
 
 
141

Oil bio-degradation in permeable pavements by microbial communities.  

UK PubMed Central (United Kingdom)

This paper reports on continuing research at Coventry University into the improvement of highway water quality following flow through a permeable pavement. Such pavements have been shown elsewhere to be efficient in-situ bio-reactors, capable of degrading large quantities of clean motor oil. Further laboratory research, reported here, demonstrates that a commercially obtained oil degrading, microbial mixture was not significantly better at degrading clean motor oil than the indigenous microbial biomass established within the pavement over a 4-year period, when provided with an adequate nutrient supply. Scanning electron microscopy has been used to monitor biofilm development, which has also identified that the pavement has developed a complex community structure with high bio-diversity.

Newman AP; Pratt CJ; Coupe SJ; Cresswell N

2002-01-01

142

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

UK PubMed Central (United Kingdom)

Interlocking concrete block pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (R(SL)) and surface slope (S(S)). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25 m(2) for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the R(SL) and S(S) variables. All models passed a confidence level of 95%, presenting high R(2) values and showing that R(SL) is a more influential variable than the S(S) for all clogging scenarios.

Sañudo-Fontaneda LA; Rodriguez-Hernandez J; Vega-Zamanillo A; Castro-Fresno D

2013-01-01

143

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

Science.gov (United States)

Interlocking concrete block pavements (ICBPs) have been widely used in car parks to reduce runoff. Researches have demonstrated that clogging is the most influential factor in the reduction of the infiltration capacity of this type of permeable pavement. Nevertheless, there is no laboratory study of the infiltration performance of ICBPs that combines clogging levels with variables related with the topography of car parks such as runoff surface length (R(SL)) and surface slope (S(S)). This paper studies the infiltration behaviour of ICBP during their operational life in a car park using an improved version of the Cantabrian Fixed (CF) Infiltrometer. This laboratory device simulates direct rainfall and runoff from adjacent impervious areas over an ICBPs surface of 0.25 m(2) for different slopes (0, 3, 5, 7 and 10%) and three scenarios of clogging (surface newly built, surface clogged and surface clogged with maintenance). This paper presents the results of the tests and a statistical analysis based on three regression models (corresponding to each clogging scenario) depending on the R(SL) and S(S) variables. All models passed a confidence level of 95%, presenting high R(2) values and showing that R(SL) is a more influential variable than the S(S) for all clogging scenarios. PMID:23202575

Sañudo-Fontaneda, Luis A; Rodriguez-Hernandez, Jorge; Vega-Zamanillo, Angel; Castro-Fresno, Daniel

2013-01-01

144

Materials characterization of recycled asphalt concrete pavements  

Energy Technology Data Exchange (ETDEWEB)

The depletion of quality aggregate, the increasing cost of asphalt cement, and the growth in the cost of energy have encouraged an increase in the reuse of asphalt concrete pavement materials for recycling. The increasing interest in recycling has created a need to investigate fully the physical properties of the recycled materials and to categorize their characteristics. The purpose of this study is to develop a data bank system for recycled asphalt concrete pavements and to evaluate the detailed engineering properties of recycled materials by means of an extensive laboratory investigation. The data bank is intended to identify and organize past and present records concerning the material characteristics, design, construction, cost, maintenance, and performance of recycled asphalt concrete projects. To evaluate the engineering properties of recycled asphalt concrete materials, a test program has been designed, necessary experimental equipment developed, and a series of tests conducted on various binders and mixtures. Emphasis is placed on low temperature cracking and permanent deformation phenomena. Results of the experiments are used to developes statistically based prediction models, which can be employed in predicting the low temperature tensile properties, permanent deformation and resilient modulus of any mixture of similar characteristics to those tested, under different loading and environmental conditions. The principal findings are that the recycled concrete materials possess higher stability, durability, and stiffness than conventional materials. They are also superior in terms of their ability to resist permanent deformation, but are more susceptible to low temperature cracking. Nevertheless, with proper mixture design the cracking potential can be eliminated. 160 refs., 90 figs., 30 tabs.

Hadipour, K.

1987-01-01

145

Partner discrepancies in distressed marriages.  

UK PubMed Central (United Kingdom)

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

Kilmann PR; Vendemia JM

2013-03-01

146

Moral Distress in Emergency Nurses.  

UK PubMed Central (United Kingdom)

INTRODUCTION: For nurses, moral distress leads to burnout, attrition, compassion fatigue, and patient avoidance. METHODS: Using a quantitative, cross-sectional, and descriptive design, we assessed the frequency, intensity, and type of moral distress in 51 emergency nurses in 1 community hospital using a 21-item, self-report, Likert-type questionnaire. RESULTS: Results showed a total mean moral distress level of 3.18, indicative of overall low moral distress. DISCUSSION: Situations with the highest levels of moral distress were related to the competency of health care providers and following family wishes to continue life support, also known as futile care. Moral distress was the reason given by 6.6% of registered nurses for leaving a previous position, 20% said that they had considered leaving a position but did not, and 13.3% stated that they are currently considering leaving their position because of moral distress.

Fernandez-Parsons R; Rodriguez L; Goyal D

2013-02-01

147

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

Science.gov (United States)

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

148

Evaluation of Three Porous Pavement Systems in a Newly Constructed Parking Lot  

Science.gov (United States)

This project examines porous pavement systems in a newly constructed parking lot next to Building 205 at the Edison Environmental Center. Porous pavement systems are one means of promoting environmental sustainability through stormwater runoff reduction. This project examines t...

149

STUDY ON FLOOD CONTROL PROPERTIES OF PERMEABLE PAVEMENT USING SATURATED-UNSATURATED SEEPAGE ANALYSIS  

Science.gov (United States)

The rainfall storage and infiltration facility of permeable pavement have been attracted attention as a control measure of flood and an environmental improvement measure in urban areas. However, rainfall infiltration of permeable pavement is unsteady flow and strongly dependent on the behavior of unsaturated zones in the pavement. Moreover, the wet condition of subbase course also has a great influence on the rainfall infiltration of the pavement. That's why previous studies have not made clear the precise the facility of permeable pavement as a flood control. In this paper, experimental studies and simulated analyses were performed to measure the overflow from the pavement under various conditions of rainfall intensities and estimate the rainfall infiltration of the pavement using the measurement data and unsaturated infiltration characteristics of porous asphalt materials. It is clear that this study shows the methods to have a quantitative estimation of the rainfall storage and infiltration facility of permeable pavement.

Yano, Takao; Nishiyama, Satoshi; Ohnishi, Yuzo; Nakashima, Shinichiro; Moriishi, Kazushi; Wada, Minoru

150

Passive pavement-mounted acoustical linguistic drive alert system and method  

Energy Technology Data Exchange (ETDEWEB)

Systems and methods are described for passive pavement-mounted acoustical alert of the occupants of a vehicle. A method of notifying a vehicle occupant includes providing a driving medium upon which a vehicle is to be driven; and texturing a portion of the driving medium such that the textured portion interacts with the vehicle to produce audible signals, the textured portion pattern such that a linguistic message is encoded into the audible signals. The systems and methods provide advantages because information can be conveyed to the occupants of the vehicle based on the location of the vehicle relative to the textured surface.

Kisner, Roger A. (Knoxville, TN); Anderson, Richard L. (Oak Ridge, TN); Carnal, Charles L. (Cookeville, TN); Hylton, James O. (Clinton, TN); Stevens, Samuel S. (Harriman, TN)

2001-01-01

151

Recycled asphalt pavement as a base and sub-base material  

Energy Technology Data Exchange (ETDEWEB)

Laboratory and field investigations were conducted to evaluate the use of recycled asphalt pavement (RAP) in roadway base and sub-base applications. The laboratory resilient modulus test results showed RAP has comparable strength with dense graded aggregate base and sub-base material used in the state of New Jersey. Using the spectral-analysis-of-the-surface-waves method (SASW), the field testing program evaluated the elastic modulus of the RAP base in the field and verified the laboratory results. The field test results showed higher modulus and stiffness for RAP than the dense graded aggregate base normally used in state of New Jersey.

Maher, M.H.; Gucunski, N.; Papp, W.J. Jr. [Rutgers Univ., Piscataway, NJ (United States). Dept. of Civil and Environmental Engineering

1997-12-31

152

The deterioration with age of asphalt concrete pavement incorporating fly ash filler  

Energy Technology Data Exchange (ETDEWEB)

Annual production of fly ash in Japan is steadily increasing, and is now around four million tonnes per year. Regarding its utilization, fly ash meets all the relevant standards for asphalt concrete fillers. The authors therefore conducted a comparative study of the durability and stability of pavement surfaces consisting of asphalt concrete with either fly ash or limestone powder as the filler. The study, which lasted four years, has confirmed that a fly ash filler gives results which are at least as good as those obtained using powdered limestone. 2 figs., 3 tabs.

Yasuda, M.; Hozumi, Y.

1985-01-01

153

Development of ceramic pavement tile using coal ash - the pavement tile as water absorption and evaporation  

Energy Technology Data Exchange (ETDEWEB)

This paper introduces an effective new method of using coal ash for ceramic tiles. The ceramic tile contains over 70% of coal ash and has many special characteristics, such as high water absorption and slow evaporation. This makes it particularly suitable for mitigating flooding and heat-island phenomena, which have become serious problems in cities due to the increasing coverage of land area by concrete and asphalt. Furthermore the ceramic tile has two to three times the bending strength of concrete. The use of ceramic tiles in pavements is described. 2 figs.

Ikeda, M.; Sugiura, S.; Ikami, H. [Tetra Co., Ltd., Tokyo (Japan). Technical Dept.

1996-08-01

154

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

Science.gov (United States)

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

155

Bearing capacity evaluation of rubblized concrete pavements  

Directory of Open Access Journals (Sweden)

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

Thenoux, G.; González, M.

2009-01-01

156

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

Science.gov (United States)

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

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

2012-01-01

157

Stormwater quality performance of a macro-pervious pavement car park installation equipped with channel drain based oil and silt retention devices.  

UK PubMed Central (United Kingdom)

This paper reports the results of a two year field monitoring exercise intended to investigate the pollution abatement capabilities of a novel system which offers an alternative to the, now well established, pervious pavement system as a source control device for stormwater management. The aim of this study was to determine the effectiveness of a live installation of a macro-pervious pavement system (MPPS) (operated as a visitors' car park at a prison in Central Scotland) in retaining and treating a range of pollutants which originate from automobile use or become concentrated on the parking surface from the wider environment. The MPPS is a sub-class of pervious pavement system where the vast majority of the surface is impermeable. It directs stormwater into a pervious sub surface storage/attenuation zone through a series of distinct infiltration points fast enough to prevent flooding during the design storm. In the particular system studied here the infiltration points consist of a network of oil/silt separation devices with extensive further pollutant retention/degradation provided during the passage of stormwater through the sub surface zone. Approximately 12 months after the car park was completed a sampling regime was instigated in which grab samples were collected at intervals from each of the three sub catchments whilst, simultaneously, samples were collected directly from the, pollutant retaining, infiltration devices. Through investigation of samples collected at the upstream end of the system, the retention of significant amounts of hydrocarbons and heavy metals in the initial collection devices has been illustrated and the analysis of effluent samples collected at the outlet points indicate that the system is capable of producing effluent which is of a standard comparable to that expected from a traditional pervious pavement system and is acceptable for direct release into a surface water receptor. The system offers the opportunity to accrue the benefits of a pervious pavement when the use of traditional paving surfaces is the preferred option.

Newman AP; Aitken D; Antizar-Ladislao B

2013-07-01

158

Evaluation of Road Pavement Density Using Ground Penetrating Radar  

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

159

Maternal distress: a concept analysis.  

UK PubMed Central (United Kingdom)

AIM: This paper is a report of an analysis of the concept of maternal distress. BACKGROUND: Although not well-developed, the concept of maternal distress has offered an important viewpoint in nursing and midwifery practice since the mid-1990s. Traditionally, understanding of maternal distress has been based on the medical model and dysfunction. The concept of maternal distress needs development so that it describes responses ranging from normal stress responses to those indicating mental health problem/s. DATA SOURCES: The SCOPUS, CINAHL and Medline databases were searched for the period from 1995 to 2009 using the keywords 'psychological distress', 'emotional distress' and 'maternal distress'. REVIEW METHODS: Steps from Rodgers' evolutionary concept analysis guided the conduct of this concept analysis. RESULTS: Four attributes of maternal distress were identified as responses to the transition to motherhood, with the level of each response occurring along a continuum: stress, adapting, functioning and control, and connecting. Antecedents to maternal distress include becoming a mother, role changes, body changes and functioning, increased demands and challenges, losses and gains, birth experiences, and changes to relationships and social context. The consequences of maternal distress are compromised mental health status, maternal role development, quality of life, ability to function, quality of relationships and social engagement. The extent of the impact depends on the level of maternal distress. CONCLUSION: Clearer interpretation of maternal distress offers a comprehensive approach to understanding maternal emotional health during the transition to motherhood. Acknowledging women's experiences and providing more appropriate support could alleviate some of the struggles and hardships experienced by mothers.

Emmanuel E; St John W

2010-09-01

160

Predicting Financial Distress and the Performance of Distressed Stocks  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In this paper, we consider the measurement and pricing of distress risk.We present a model of corporate failure in which accounting and market-based measures forecast the likelihood of future financial distress. Our best model is more accurate than leading alternative measures of corporate failure r...

Campbell, John Y.; Hilscher, Jens Dietrich; Szilagyi, Jan

 
 
 
 
161

Evaluating Functional and Structural Condition Based Maintenances of Airfield Pavements  

Directory of Open Access Journals (Sweden)

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

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

2013-01-01

162

Microwave methods enable energy savings in restoration of highway pavements  

Energy Technology Data Exchange (ETDEWEB)

Hot in place recycling of asphalt pavement by a method which utilizes microwave energy in combination with hot engine exhaust gases has been demonstrated to be technically and economically feasible. The process saves both energy and materials compared with conventional hot-mix recycling methods involving removal of old paving and reprocessing at hot-mix plants. Applications for microwave pavement heating include repair of cracks, joints between lanes and shoulders, wheel tracks, bridge decks, strip patching, and eventually in-place of full lanes of asphalt highways. The ability of microwave energy to heat pavements rapidly and fairly uniformly to depths of up to 6 inches make this new method uniquely suitable for repair and restoration of bridges, roads and highways, and also for the construction of new paved roads in places where hot-mix plants are not available.

Jeppson, M.R.; Smith, F.J.

1983-08-01

163

Evaluation of Common Maintenance Methods for Flexible Pavements  

Directory of Open Access Journals (Sweden)

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

Asma T. Ibraheem; Suda M. Gani

2011-01-01

164

Performance of waste tyre rubber on model flexible pavement  

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

165

Interlocking Paving Stones Pavement as a Solution to Marshy Roads  

Directory of Open Access Journals (Sweden)

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

Oluwapelumi O. Ojuri

2012-01-01

166

Calibrating mechanistic-empirical pavement performance models with an expert matrix  

Energy Technology Data Exchange (ETDEWEB)

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, or in terms of performance as a Pavement Condition Index. This new model can be re-calibrated to apply to conditions other than Ontario conditions. Examples of various design situations were included. 10 refs., 7 tabs., 5 figs.

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

167

Distressed transvestites. Psychometric characteristics.  

UK PubMed Central (United Kingdom)

Transvestic fetishism is characterized by eroticized cross-dressing in a heterosexual male. Twenty-one transvestites who were seeking psychiatric consultation were evaluated using the Derogatis Sexual Functioning Inventory (DSFI) and the Brief Symptom Inventory (BSI). They were compared with 45 heterosexual married males. The transvestic group was significantly more distressed on most dimensions of the BSI. The transvestic group displayed a more negative body image, a more feminine gender role perception, and less experience than the comparison group on the DSFI. Those transvestites who had no homosexual experience were less frequently gender dysphoric but more frequently had a concurrent axis I disorder. The transvestite with recent homosexual experience reported an earlier age when cross-dressing began. These findings are discussed in the context of previous research on transvestism.

Fagan PJ; Wise TN; Derogatis LR; Schmidt CW

1988-10-01

168

[Acute respiratory distress syndrome].  

UK PubMed Central (United Kingdom)

Acute respiratory distress syndrome (ARDS) is the clinical manifestation of an acute lung injury caused by a variety of direct and indirect injuries to the lung. The cardinal clinical feature of ARDS, refractory arterial hypoxemia, is the result of protein-rich alveolar edema with impaired surfactant function, due to vascular leakage and dysfunction with consequently impaired matching of ventilation to perfusion. Better understanding of the pathophysiology of ARDS has led to the development of novel therapies, pharmacological strategies, and advances in mechanical ventilation. However, protective ventilation is the only confirmed option in ARDS management improving survival, and few other therapies have translated into improved oxygenation or reduced ventilation time. The development of innovative therapy options, such as extracorporeal membrane oxygenation, have the potential to further improve survival of this devastating disease.

Hecker M; Weigand MA; Mayer K

2012-05-01

169

Riding Quality Model for Asphalt Pavement Monitoring Using Phase Array Type L-band Synthetic Aperture Radar (PALSAR)  

Directory of Open Access Journals (Sweden)

Full Text Available There are difficulties associated with near-real time or frequent pavement monitoring, because it is time consuming and costly. This study aimed to develop a binary logit model for the evaluation of highway riding quality, which could be used to monitor pavement conditions. The model was applied to investigate the influence of backscattering values of Phase Array type L-band Synthetic Aperture Radar (PALSAR). Training data obtained during 3–7 May 2007 was used in the development process, together with actual international roughness index (IRI) values collected along a highway in Ayutthaya province, Thailand. The analysis showed that an increase in the backscattering value in the HH or the VV polarization indicated the poor condition of the pavement surface and, of the two, the HH polarization is more suitable for developing riding quality evaluation. The model developed was applied to analyze highway number 3467, to demonstrate its capability. It was found that the assessment accuracy of the prediction of the highway level of service was 97.00%. This is a preliminary study of the proposed technique and more intensive investigation must be carried out using ALOS/PALSAR images in various seasons.

Weerakaset Suanpaga; Kamiya Yoshikazu

2010-01-01

170

Predicting physical clogging of porous and permeable pavements  

Science.gov (United States)

? We conducted two laboratory experiments over 3 years on three porous pavement types. ? Continual wetting with no drying, and variable inflow with drying were simulated. ? Variable inflow and drying periods approximately doubled the lifespan of all systems. ? A simple regression model to predict hydraulic resistance (clogging) was developed. ? Hydraulic resistance is an exponential function of cumulative volume and flow rate.

Yong, C. F.; McCarthy, D. T.; Deletic, A.

2013-02-01

171

Pavement wear and airborne dust pollution in Norway  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Snilsberg, Brynhild

172

Prediction of subgrade moisture conditions for purposes of pavement design  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 capabil...

Correia, A. Gomes

173

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...

174

Combined permeable pavement and ground source heat pump systems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The PhD thesis focuses on the performance assessment of permeable pavement systems incorporating ground source heat pumps (GSHP). The relatively high variability of temperature in these systems allows for the survival of pathogenic organisms within the sub?base. Salmonella sp, Escherichia coli, Ente...

Grabowiecki, Piotr

175

The Edison Environmental Center Permeable Pavement Site - slides  

Science.gov (United States)

This is a presentation for a second Community Outreach Event called "Chemistry Works!" at West Windsor Public Library on Saturday, November 5th. It will review the permeable pavement research project at the Edison Environmental center. Besides slide persentation, two demo units w...

176

Weed occurrence on pavements in five North European towns  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Weeds on pavements in urban areas are unwanted mainly because they cause an untidy appearance or sometimes structural damage. Glyphosate has been the principal weed control method for years, but policies in several European towns have changed to lower dependence on herbicides. Instead, less effectiv...

Melander, B.; Holst, N.; Grundy, A.; Kempenaar, C.; Riemens, M.M.; Verschwele, A.; Hansson, D.

177

Long-term salt marsh recovery and pavement persistence at {sup M}etula` spill sites  

Energy Technology Data Exchange (ETDEWEB)

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

Owens, E. H. [Polaris Applied Sciences, Bainbridge Island, WA (United States); Sergy, G. A. [Environment Canada, Edmonton, AB (Canada); Guzman, M. L. [Instituto de Fomento Pesquero, Punta Arenas (Chile); Wang, Z. [Environment Canada. Ottawa, ON (Canada); Baker, J. [Ruyton-XI-Towns (United Kingdom)

1999-08-01

178

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

International Nuclear Information System (INIS)

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

1999-01-01

179

Electrical resistance tomography for monitoring the infiltration of water into a pavement section  

Energy Technology Data Exchange (ETDEWEB)

Electrical resistance tomography (ERT) was used to follow the infiltration of water into pavement section at the UC Berkeley Richmond Field Station. A volume of pavement 1m square and 1.29 m deep was sampled by an ERT array consisting of electrodes in 9 drilled holes plus 8 surface electrodes. The data were collected using a computer controlled data acquisition system capable of collecting a full data set in under 1 hour, allowing for nearly real time sampling of the infiltration. The infiltration was conducted in two phases. During the first phase, water was introduced into the asphalt-concrete (AC) layers at a slow rate of about 8 ml per hour for a period of about 6 days. In the second phase, water was introduced into the asphalt-treated-permeable base (ATPB) layer at a more rapid rate of about 100 ml/h for about 2 days. The ERT images show that water introduced into the upper AC layers shows up as a decrease in resistivity which grows with time. The images also appear to show that when water moves into the layers below the ATPB, the resistivity increases; an unexpected result. There are some indications that the water moved laterally as well as down into the deeper ATPB and the aggregate base. The images also show that when water is introduced directly into the ATPB and aggregate layer, the water moves into the the underlying materials much more quickly.

Buettner, M.; Daily, B.; Ramirez, A.

1997-07-03

180

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

UK PubMed Central (United Kingdom)

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.

Pardillo Mayora JM; Jurado Piña R

2009-07-01

 
 
 
 
181

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

Science.gov (United States)

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

Pardillo Mayora, José M; Jurado Piña, Rafael

2009-05-27

182

Filtration and clogging of permeable pavement loaded by urban drainage.  

Science.gov (United States)

Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (?(e)) of 24% and median pore size of 658 ?m with a standard deviation of 457 ?m. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 ?m and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 × 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage. PMID:22123518

Sansalone, J; Kuang, X; Ying, G; Ranieri, V

2011-11-10

183

Filtration and clogging of permeable pavement loaded by urban drainage.  

UK PubMed Central (United Kingdom)

Permeable pavement, as a sustainable infrastructure material can promote hydrologic restoration, particulate matter (PM) and solute control. However, filtration and commensurate clogging are two aspects of continued interest and discussion. This study quantifies filtration and clogging of cementitious permeable pavement (CPP) for loadings from 50 to 200 mg/L of hetero-disperse sandy-silt PM. The CPP mix design provides a hetero-disperse pore size distribution (PSD)(pore), effective porosity (?(e)) of 24% and median pore size of 658 ?m with a standard deviation of 457 ?m. The PM mass separation across the entire particle size distribution (PSD)(PM) exceeds 80%; with complete separation for PM greater than 300 ?m and 50% separation for suspended PM. Turbidity is reduced (42-95%), and effluent is below 10 NTU in the first quartile of a loading period. Permeable pavement illustrates reductions in initial (clean-bed) hydraulic conductivity (k(0)) with loading time. For all PM loadings, k(0) (3.1 × 10(-1) mm/s) was reduced to 10(-4) mm/s for runoff loading durations from 100 to 250 h, respectively. Temporal hydraulic conductivity (k) follows exponential profiles. Maintenance by vacuuming and sonication illustrate that 96-99% of k(0) is recovered. Permeable pavement constitutive properties integrated with measured PM loads and a year of continuous rainfall-runoff simulation illustrate k reduction with historical loadings. Study results measure and model filtration and hydraulic conductivity phenomena as well as maintenance requirements of permeable pavement directly loaded by urban drainage.

Sansalone J; Kuang X; Ying G; Ranieri V

2012-12-01

184

[Acute respiratory distress disclosing leptospirosis  

UK PubMed Central (United Kingdom)

The respiratory manifestations of leptospirosis are usually benign. A case is reported of anicteric leptospirosis with serious pulmonary affection. The clinical symptoms, the radiological manifestations and haemodynamic investigation were suggestive of an acute respiratory distress by non-haemodynamic pulmonary oedema. In accordance with other authors, one would be justified in including this acute respiratory failure as part of the acute respiratory distress syndrome of the adult (ARDS).

Perdrix C; Clément C; Druart F

1986-01-01

185

Mechanical behavior of flexible pavements undergoing thermal gradients  

Directory of Open Access Journals (Sweden)

Full Text Available The proper structural understanding of a pavement should consider, according to the pavement mechanics, the aspects related to the traffic load, the environment and material properties. When asphaltic materials are used, the stress/strain relationships and the dependencies of load-time and temperature are key parameters for understanding flexible pavement performance. In this study, we employed the finite elements method to calculate stress/strain in flexible pavements structures considering temperature variation. The input data includes material stiffness, which is function of temperature and changes with position and time. The pavement temperature is obtained through the heat transfer differential equation, applying the Laplace transform and its numerical inversion. The finite elements grid was generated by the software ANSYS® and imported by the software MATLAB®. In order to determine the stiffness of the first layer (asphalt concrete) we used the average of four nodes, depending on the each node temperature. The result evidences the importance of thermal gradients for the pavement analysis, both for the fatigue cracking and the accumulation of plastic deformations. The use of unique modulus for asphalt concrete layer generates results far from reality.O adequado entendimento estrutural de um pavimento deve considerar, segundo a mecânica dos pavimentos, os aspectos relacionados aos carregamentos, ao meio físico e às propriedades dos materiais constituintes. No caso de materiais asfálticos, as relações entre tensão e deformação e as dependências do tempo de carregamento e da temperatura são fundamentais para o avanço no entendimento do desempenho de pavimentos flexíveis. Neste trabalho foi utilizando o método de elementos finitos para o cálculo das tensões e deformações em pavimentos flexíveis considerando variações de temperatura. Os dados de entrada incluem a rigidez dos materiais, que é função da temperatura, a qual varia com a posição e com o tempo. A temperatura do pavimento é obtida através da resolução da equação diferencial de transferência de calor aplicando a transformação de Laplace e sua inversa numérica e considerando a variação de temperatura do ambiente. A malha de elementos finitos foi gerada pelo software ANSYS® e os dados foram importados pelo software MATLAB®. No cálculo da rigidez de cada elemento da primeira camada (revestimento asfáltico), substitui-se o módulo pela média dos quatro nós, dependendo da temperatura de cada nó que por sua vez é calculada na análise de transferência de calor. O resultado mostra a grande importância dos gradientes térmicos para a análise do comportamento do pavimento, tanto no que se refere ao trincamento por fadiga quanto ao acúmulo das deformações plásticas. O uso da rigidez da camada asfáltica constante provoca resultados distantes da realidade.

Grazielli Vassoler; Wang Chong; Luciano Pivoto Specht

2011-01-01

186

Influence of Three Permeable Pavement Surfaces on Nitrogen Treatment  

Science.gov (United States)

Nitrogen is a stressor of concern in many nutrient sensitive watersheds often associated with algal blooms and resulting fish kills. Communities are increasingly installing green infrastructure stormwater control measures (SCMs) to reduce pollutant loads associated with stormwat...

187

Use of Recycled Aggregate and Fly Ash in Concrete Pavement  

Directory of Open Access Journals (Sweden)

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.

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

2011-01-01

188

AN OPTIMAL MAINTENANCE MANAGEMENT MODEL FOR AIRPORT CONCRETE PAVEMENT  

Science.gov (United States)

In this paper, an optimal management model is formulated for the performance-based rehabilitation/maintenance contract for airport concrete pavement, whereby two types of life cycle cost risks, i.e., ground consolidation risk and concrete depreciation risk, are explicitly considered. The non-homogenous Markov chain model is formulated to represent the deterioration processes of concrete pavement which are conditional upon the ground consolidation processes. The optimal non-homogenous Markov decision model with multiple types of risk is presented to design the optimal rehabilitation/maintenance plans. And the methodology to revise the optimal rehabilitation/maintenance plans based upon the monitoring data by the Bayesian up-to-dating rules. The validity of the methodology presented in this paper is examined based upon the case studies carried out for the H airport.

Shimomura, Taizo; Fujimori, Yuji; Kaito, Kiyoyuki; Obama, Kengo; Kobayashi, Kiyoshi

189

DYNAMIC JOINT LOAD TRANSFER EFFICIENCY OF RIGID PAVEMENT  

Directory of Open Access Journals (Sweden)

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(S)dynamic/ LTE(S)static) varies in the range 1 to 2 mainly depending on speed v and damping Cs;(4) The LTE(S)dynamic 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.

YU Xinhua; WU Xiaochun

2011-01-01

190

Should we be gritting pavements to prevent pedestrian injuries?  

UK PubMed Central (United Kingdom)

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

Atenstaedt R; Rees M

2013-05-01

191

Long-term cracking resistance of asphaltic concrete pavement / ?????????? ???????????????? ?????????????? ???????? ????????  

Directory of Open Access Journals (Sweden)

Full Text Available The main influence factors on the long-term cracking resistance of asphaltic concrete pavement are reviewed. The indicator of long-term cracking resistance and calculating experimental method of minimum quantity defining of cycles of asphaltic concrete stressing till crack formation in compliance with climatic conditions and traffic load is offered. The results of the comparative analysis of long-term cracking resistance of different asphalt concrete are described./ ??????????? ???????? ???????, ???????? ?? ?????????? ???????????????? ?????????????? ? ????????. ????????? ?????????? ?????????? ???????????????? ? ????????-????????????????? ????? ??????????? ???????????? ?????????? ?????? ?????????? ?????????????? ?? ??????????? ??????? ? ?????? ????????????? ???????? ? ???????????? ????????. ????????? ?????????? ?????????????? ??????? ?????????? ???????????????? ????????? ???????????????.

Uglova Ye.V. / ?????? ??????? ????????????; Besschetnov B.V. / ?????????? ?.?.

2011-01-01

192

The construction of concrete pavement incorporating coal ash  

Energy Technology Data Exchange (ETDEWEB)

In recent years, many Japanese thermal power plants have been converted from fuel oil to coal firing, with a resulting increase in the production of coal ash. Many ways of utilizing this ash are now applied on a practical basis. The authors report the use of coal ash as an admixture in concrete used for pavement at the site of Joban Joint Thermal Power's power plant. 2 figs., 3 tabs.

Origasa, M.; Itoh, H.

1985-01-01

193

Perfectionism, procrastination, and psychological distress.  

UK PubMed Central (United Kingdom)

Using a cross-panel design and data from 2 successive cohorts of college students (N = 357), we examined the stability of maladaptive perfectionism, procrastination, and psychological distress across 3 time points within a college semester. Each construct was substantially stable over time, with procrastination being especially stable. We also tested, but failed to support, a mediational model with Time 2 (mid-semester) procrastination as a hypothesized mechanism through which Time 1 (early-semester) perfectionism would affect Time 3 (end-semester) psychological distress. An alternative model with Time 2 perfectionism as a mediator of the procrastination-distress association also was not supported. Within-time analyses revealed generally consistent strength of effects in the correlations between the 3 constructs over the course of the semester. A significant interaction effect also emerged. Time 1 procrastination had no effect on otherwise high levels of psychological distress at the end of the semester for highly perfectionistic students, but at low levels of Time 1 perfectionism, the most distressed students by the end of the term were those who were more likely to have procrastinated earlier in the semester. Implications of the stability of the constructs and their association over time, as well as the moderating effects of procrastination, are discussed in the context of maladaptive perfectionism and problematic procrastination.

Rice KG; Richardson CM; Clark D

2012-04-01

194

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

Science.gov (United States)

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

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

2012-05-01

195

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

UK PubMed Central (United Kingdom)

This paper describes a study that used permeability measurement along with physical and hydrological characteristics of 20 pervious concrete pavements in parking lots throughout California. The permeability was measured at five locations: the main entrance, an area with no traffic, and three separate measurements within a parking space at each parking lot. Hydrological and physical site characteristics such as traffic flow, erosion, vegetation cover, sediments accumulation, maintenance practice, presence of cracking, rainfall, and temperature data were also collected for each parking lot. These data were used to perform detailed statistical analysis to determine factors influencing changes in permeability and hence assessing possible cause of clogging. In addition, seven representative core samples were obtained from four different parking lots with permeability ranging from very low to very high. Porosity profiles produced from CT scanning were used to assess the possible nature and extent of clogging. Results showed that there is a large variation in permeability within each parking lot and between different parking lots. In general, the age of the parking lot is the predominant factor influencing the permeability. Statistical analysis revealed that fine sediment (particles less than 38 ?m) mass is also an important influencing factor. Other influencing factors with lower significance included number of days with a temperature greater than 30°C and the amount of vegetation next to the parking lot. The combined scanned image analysis and porosity profile of the cores showed that most clogging occurs near the surface of the pavement. While lower porosity generally appeared to be limited to the upper 25 mm, in some core samples evidence of lower porosity was found up to 100mm below the surface.

Kayhanian M; Anderson D; Harvey JT; Jones D; Muhunthan B

2012-03-01

196

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

Science.gov (United States)

This paper describes a study that used permeability measurement along with physical and hydrological characteristics of 20 pervious concrete pavements in parking lots throughout California. The permeability was measured at five locations: the main entrance, an area with no traffic, and three separate measurements within a parking space at each parking lot. Hydrological and physical site characteristics such as traffic flow, erosion, vegetation cover, sediments accumulation, maintenance practice, presence of cracking, rainfall, and temperature data were also collected for each parking lot. These data were used to perform detailed statistical analysis to determine factors influencing changes in permeability and hence assessing possible cause of clogging. In addition, seven representative core samples were obtained from four different parking lots with permeability ranging from very low to very high. Porosity profiles produced from CT scanning were used to assess the possible nature and extent of clogging. Results showed that there is a large variation in permeability within each parking lot and between different parking lots. In general, the age of the parking lot is the predominant factor influencing the permeability. Statistical analysis revealed that fine sediment (particles less than 38 ?m) mass is also an important influencing factor. Other influencing factors with lower significance included number of days with a temperature greater than 30°C and the amount of vegetation next to the parking lot. The combined scanned image analysis and porosity profile of the cores showed that most clogging occurs near the surface of the pavement. While lower porosity generally appeared to be limited to the upper 25 mm, in some core samples evidence of lower porosity was found up to 100mm below the surface. PMID:22115516

Kayhanian, Masoud; Anderson, Dane; Harvey, John T; Jones, David; Muhunthan, Balasingam

2011-11-13

197

Stress and distress.  

UK PubMed Central (United Kingdom)

I must ask the reader's indulgence for this article's concern with applications of the stress concept, which are distinct from, although related to clinical medicine. It has not been my object to deal with the way physicians have been aided by stress research in the practice of medicine--that information is already widely available. Rather, I have attempted to sketch briefly the history of the stress theory and to demonstrate how this information can help anyone, physician or layman, lead a more complete and satisfying life. The applications of the stress theory have been dealt with at length elsewhere. I believe that we can find within scientifically verified observations the basis of a code of behavior suited to our century. The great laws of nature that regulate the defenses of living beings against stress of any kind are essentially the same at all levels of life, from individual cells to entire complex human organisms and societies. It helps a great deal to understand the fundamental advantages and disadvantages of catatoxic and syntoxic attitudes by studying the biologic basis of self-preservation as reflected in syntoxic and catatoxic chemical mechanisms. When applied to everyday problems, this understanding should lead to choices most likely to provide us the pleasant eustress (from the Greek eu meaning good, as in euphoria) involved in achieving fulfillment and victory, thereby avoiding the self-destructive distress of frustration and failure. So the translation of the laws governing resistance of cells and organs to a code of behavior comes down to three basic precepts: 1. Find your own natural stress level. People differ with regard to the amount and kind of work they consider worth doing to meet the exigencies of daily life and to assure their future security and happiness. In this respect, all of us are influenced by hereditary predispositions and the expectations of our society. Only through planned self-analysis can we establish what we really want; too many people suffer all their lives because they are too conservative to risk a radical change by breaking with hiabits or traditions. 2. Altruistic egoism. The selfish (i.e., self-interested) hoarding of the goodwill, respect, esteem, support, and love of our neighbors is the most efficient way to give vent to our pent-up energy and to create a more enjoyable, beautiful, or useful environment.3. Earn thy neighbor's love. This motto--which is merely a rewording of the command to "love thy neighbor as thyself"--is compatible with man's natural structure, and although it is based on altruistic egoism, it could hardly be attacked as unethical. Who would blame the man who wants to assure his own homeostasis and happiness only by accumulating the treasure of other poeple's benevolence and love? Yet this makes him virtually unassailable, for nobody wants to attack and destroy those upon whom he depends.

Selye H

1975-12-01

198

Mindfulness and bodily distress.  

UK PubMed Central (United Kingdom)

We have created a mindfulness approach to treat patients who experience multiple, persistent, and disabling physical symptoms that cannot be explained by a well-defined medical or surgical condition. Randomized controlled trials in this area are few, and research is hampered by the lack of clear definitions. Bodily distress syndrome (BDS) or bodily stress is an empirically defined definition unifying various conditions such as fibromyalgia, chronic fatigue syndrome, and somatization disorder. In the present PhD, we explored whether patients suffering from BDS may be committed to mental training in the form of mindfulness therapy, which is a mindfulness program specifically targeted patients suffering from BDS. The theoretical model for including mindfulness training in the treatment of BDS is based on identified neurobiological impairments in these patients and the neurobiological improvements that mindfulness training may offer. BDS is a major public health issue possibly associated with the pathology of the immuno-endocrine and autonomic nervous system. BDS patients are often stigmatized, and effective treatment is rarely delivered, which leaves these patients isolated, left by themselves, vulnerable to potentially harming medical and/or alternative treatments. Accordingly, there is a need for non-harming practical tools that patients can learn to master so that they can improve the ability to take responsibility for their own health and wellbeing. Mindfulness-Based Stress Reduction (MBSR) is a group program that employs mindfulness practice to alleviate suffering associated with physical, psychosomatic, and psychiatric disorders. Mindfulness-Based Cognitive Therapy (MBCT) is designed to prevent depressive relapse. Paper I and II present systematic literature reviews only of randomized controlled trials on MBSR and MBCT. The effect of MBSR has been explored on fibromyalgia in three studies, none of them showed convincing results, but gave some indications as to improvement. The reviews recommended MBSR as a useful method for improving mental health; however, lack of long-term follow-up and active control groups are limitations in most studies. MBCT was recommended as a tool for preventing depressive relapse in recovered, recurrently depressed patients, but the implication of MBSR and MBCT is problematic, especially due to the lack of well educated mindfulness teachers. We combined MBSR with cognitive behavioral therapy, CBT, specifically targeted BDS. Paper III provides original data from 119 patients enrolled in a randomized clinical trial, mindfulness therapy for BDS. The randomized controlled trial indicates that BDS patients are capable of and willing to engage in mindfulness therapy. This thesis showed that mindfulness therapy can safely and successfully engage BDS patients in mindfulness practice. Since individual CBT and psychiatric consultation have previously been found to have positive outcomes for BDS patients, we compared mindfulness therapy to an active control group entitled specialized treatment in which an individual treatment was planned in collaboration between the patient and an MD specialized in BDS, CBT, and psychiatry. Mindfulness therapy was comparable to specialized treatment in improving the quality of life and the symptoms of the patients with BDS at 15-month follow-up. For primary outcome physical health (PCS) at 15-month follow-up, different developments over time for the two treatment groups could not be established (F(3,2674) = 1.51, p = 0.21). However, in the mindfulness therapy group, PCS significant changed at the end of treatment and this change remained at 15-month follow-up, whereas no significantly change was seen in the specialized treatment group until at the 15-month follow-up. In the mindfulness therapy group, 26%; CI: 14-38 reported a marked improvement (> 1 SD) at the end of treatment compared with 10%; CI: 2-18 in the specialized treatment group. This amounts to a statistically significant difference between the groups (OR = 3.21; CI 1.05-9.78, p = 0.04). The results are i

Fjorback LO

2012-11-01

199

Development of an evaporation-optimized and water-permeable pavement  

Science.gov (United States)

During recent decades, urban areas have been threatened more frequently by flood events. Furthermore, the potential for damage from these events has increased on average. The construction of houses, streets and parking lots has caused this trend by sealing the ground surface, i.e. these water-impermeable areas reduce the natural infiltration and evaporation-rates, and in some cases it is even completely stopped. The consequence is the so called "urban water cycle". Water from precipitation cannot be stored anywhere and so there is an immediate and very high surface run-off effect. Especially after intense rain events, canalisations and sewage-treatment plants are overloaded and this leads to higher costs for water treatment and to environmental damage. A practical solution to this problem is the use of water-permeable pavements. Here higher infiltration rates lead to a groundwater recharge that is greater than that of natural soils. The consequences from using these surfaces are already noticeable in many places through increasing groundwater levels. These increases cause damage to buildings. A second difference from a natural-soil water-balance is a lower evapotranspiration rate. Up to now the evaporation rates for water-permeable pavements has not been established accurately. The aim of the applied research project at the University of Muenster, which is sponsored by the DBU (The German Federal Environmental Foundation), is to gain knowledge of urban evaporation rates and of water-permeable surfaces, especially water-permeable pavements. Water-permeable pavements consist of the paving stone surface and the two sub-base layers below. Pre-investigations show that evaporation can be influenced by the complete sub-base. Therefore, the first step was to investigate which materials are used for sub-base construction. All in all, 27 materials were collected from throughout Germany and these materials were then tested (in terms of physical and hydraulic attributes) in the soil-mechanics laboratory of the University of Muenster. For their street construction useability, and having regard to evaporation, a selection of appropriate materials were built into a test field. The test field consisted of seven hexagonal areas each about 10 m2 large, which are placed in a honeycomb manner. The evaporation measurements are carried out with a WERNER tunnel-evaporation gauge (TUV) which is able to detect the actual evaporation rate. Its functional principle also allows a direct comparison between the middle reference area and one outer area of the test field. Every measuring period lasts one week and after that the TUV is moved to between the next outer area and the reference area. So the TUV rotates over the whole test field and every measuring area is covered by a measurement. In addition, a Hellman rain-gauge near the test field enables the measurement of a direct precipitation-evaporation ratio. Since the start of the measurements in July 2008, the first results collected showed that measureable differences in evaporation rates could be detected after a few measuring periods, i.e. the differences are up to 32% between the reference area and one outer area. In July 2009, the six outer measuring areas of the test field will be replaced and, based on the actual results collected, the sub-base layers will be replaced by an evaporation-optimized sub-base. The new outer measuring areas will only differ in terms of a different paving-stone surface. These paving stones are actually under developement and under laboratory testing (i.e. permeability, porosity, capillary water and evaporationrates), and so they will be evaporation-opimized. The open-air test in the test field is to assure and compare the evaporation rates. As a final result, the evaporation-optimized and water-permeable pavement and the knowledge of its exact drainage ratio will allow city planners or architects to build water-permeable streets with due regard to the respective area-specific conditions. This new developed pavement is an approximation to the water balanc

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

2009-04-01

200

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

Science.gov (United States)

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…

Dave, Eshan V.

2009-01-01

 
 
 
 
201

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

Science.gov (United States)

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.

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

2013-06-01

202

Field Evaluation of Nondestructive Tests in Measuring the Pavement Layers Density  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The aim of this study was field evaluation of nondestructive devices in measuring the density of road layers. Density may be considered as a reliable criterion for evaluating pavement quality and has a high level of importance in that it can ensure the proper performance of pavement at least prior t...

H. Ziari; H. Behbahani; A. Izadi; H. Divandary

203

Porous Pavement for Control of Highway Runoff: Annual Monitoring Report (1st).  

Science.gov (United States)

A three-lane by 3500 linear feet portion of an urban highway was constructed of porous pavement. This design resulted from a research study of the use of porous pavement to provide highway drainage. It was determined that after one year of observation, th...

W. R. Meier E. Elnicky

1988-01-01

204

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

Science.gov (United States)

...currently doing tire pavement noise research? (a) If you have done or currently are doing tire pavement research: What is this research? Why are you doing this research? How are you or how do you plan on implementing this research? What...

2013-05-08

205

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

Directory of Open Access Journals (Sweden)

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

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

2010-01-01

206

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

Science.gov (United States)

The EPAâ??s Urban Watershed Management Branch (UWMB) is monitoring an instrumented, working, 110-space pervious pavement parking at EPAâ??s Edison Environmental Center (EEC). Permeable pavement systems are classified as stormwater best management practices (BMPs) which reduce runo...

207

Permeable pavement monitoring at the EPA's Edison Environmental Center demonstration site  

Science.gov (United States)

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

208

The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring  

Science.gov (United States)

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

209

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

Science.gov (United States)

The EPAâ??s Urban Watershed Management Branch has been monitoring an instrumented 110-space pervious pavement parking lot. The lot is used by EPA personnel and visitors to the Edison Environmental Center. The design includes 28-space rows of three permeable pavement types: asphal...

210

Development and psychometric testing of a new tool for detecting moral distress: the Moral Distress Thermometer.  

UK PubMed Central (United Kingdom)

AIM: To report the development and psychometric testing of the Moral Distress Thermometer. The Moral Distress Thermometer is a new screening tool to measure moral distress in nurses who practise in the hospital setting. BACKGROUND: Moral distress occurs when one knows the ethically correct thing to do, but is prevented from acting on that perceived obligation. It is a well documented phenomenon with negative consequences that may be experienced by nurses. Creating an instrument to effectively and efficiently measure moral distress in a timely way has been identified as a priority for nursing. DESIGN: This study used a cross-sectional survey design. METHODS: Data collection for this research occurred in 2009. Participants simultaneously completed either the adult or pediatric version of the Moral Distress Scale version 2009 and the Moral Distress Thermometer. A total of 529 participants from various clinical areas completed both tools. RESULTS: Coefficients alpha were adequate for both Adult (0·90) and Pediatric (0·92) Moral Distress Scale 2009 scales. Statistically significant Pearson correlations were found for the Moral Distress Thermometer with Adult Moral Distress Scale 2009 and Pediatric Moral Distress Scale 2009 and higher Moral Distress Thermometer, Adult Moral Distress Scale 2009 and Pediatric Moral Distress Scale 2009 means for participants who had left or who considered leaving a position because of moral distress. CONCLUSION: These findings provide support for the validity of the Moral Distress Thermometer.

Wocial LD; Weaver MT

2013-01-01

211

Insular Lateralization in Tinnitus Distress  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Tinnitus affects 15% of the population. Of these 1-2% are severely disabled by it. The role of the autonomic system in tinnitus is hardly being investigated. The aim of this study is to investigate the relationship between tinnitus distress and lateralization of the anterior insula, known to be invo...

Van Der Loo, Elsa; Congedo, Marco; Vanneste, Sven; Van De Heyning, Paul; De Ridder, Dirk

212

Perfectionism, Procrastination, and Psychological Distress  

Science.gov (United States)

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

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

2012-01-01

213

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.

2010-05-01

214

Technical development of cost-efficient installation of power distribution cables under pavements. Haiden chichuka ni okeru doboku kensetsu gorika gijutsu no kaihatsu  

Energy Technology Data Exchange (ETDEWEB)

Various latest technical developments were surveyed for the cost-effective installation of power distribution cables under pavements, and their applicabilities were demonstrated with the evaluation of their cost-reduction effects. Cables in conventional vinyl protection tubes could be buried only 30cm under pavements, and in such case, the cost was reduced to 51% of those of conventional methods. As the results of soil tests, excavated soil over 80% was reusable through coarse screening. Underground radar technique to explore buried pipes from the surface was detectable several pipes buried 1.5-2.0m underground, although some problems in precision were found. The improvement of reinforced concrete man-hole structures to minimize the volume of excavated soil indicated the cost reduction of nearly 20%. The application of these techniques to the installation of cables was expected to ultimately halve the total civil engineering cost. 21 refs., 130 figs., 46 tabs.

Kokusho, Koji; Kataoka, Tetsuyuki; Tanaka, Yasuyuki; Yoshida, Yasuo; Ikemi, Motoyoshi; Suzuki, Koichi; Kitano, Koichi; Kobayashi, Seiichi; Kanazu, Tsutomu; Komada, Hiroya.

1987-12-01

215

Diabetes distress among type 2 diabetic patients  

Directory of Open Access Journals (Sweden)

Full Text Available Background: Diabetes mellitus is being increasingly recognized as a serious global health problem and is frequently associated with co-morbid distress, contributing double burden for the individual and the society. Aim: This study documents the proportion of diabetes distress and factors associated with it. Methods: A cross-sectional study was conducted from January to June 2012. Data were collected through interview and record review of 165 adults with type 2 diabetes. Results: The proportion of diabetes distress among the study population was 48.5%, which includes 22.4% high distress and 26.1% moderate distress. The remainder had little or no distress. The Mean ± SD of total diabetes distress score was2.17 ± 0.75. The Mean ± SD for each domain score such as emotional burden, physician-related distress, regimen-related distress and interpersonal distress was (3.49 ± 1.52), (1.13 ± 0.32), (2.12 ± 0.85), (1.40± 0.65) respectively. Emotional burden was considered as the most important domain in measuring diabetes distress. The influence of age (p<0.001), occupation (p<0.05), smoking (p<0.005), BMI (p<0.001), duration since detection of diabetes mellitus (p<0.001), glycaemic status (p<0.001) treatment modalities (P<0.001), diabetic complications (p<0.001) on level of diabetes distress was statistically significant. There was a strong, positive correlation between the two variables (r=0.64, p<0.001); diabetes distress score with duration of diabetes mellitus. There was a medium, positive correlation between the two variables [r=0.43, p<0.001]; diabetes distress score with glycaemic status (HbA1c level) .Conclusion: This study identified diabetes distress as a significant health problem among adult type 2 diabetes mellitus patients. This should be taken into consideration for effective management of patient.

Islam MR; Karim MR; Habib SH; Yesmin K

2013-01-01

216

Permeable Pavement Research â?? Edison, NJ  

Science.gov (United States)

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

217

Application of roller compacted concrete pavement in port yards. Ten'atsu concrete hoso no kowan shisetsu eno tekiyo  

Energy Technology Data Exchange (ETDEWEB)

The pavement in port yards have a characteristic of having a high using ratio of heavy vehicles compared to common roads, and has difference from the pavement in common roads in the aspect of loads and the running frequency. Commonly, in the pavement in port yards, since concrete having a high rigidity has more benefit than the asphalt pavement, it is considered to be greatly high application to Roller Compacted Concrete Pavement (RCCP). RCCP has an advantage in construction and early usage, however, it remains weak points on limitation of plate thickness for sufficiently confirming density in a common construction method of one-layer and reinforcement of the pointing parts by slip bars. Then, in this study, as an object of pavement in port yards, the paving structure, the pointing structure and construction of RCCP were experimentally examined, and application of RCCP to pavement in port yards was investigated. 6 refs., 19 figs.

Hachiya, Y.; Fukute, T. (Port and Harbour Research Inst., Yokosuka (Japan))

1994-02-01

218

Flyash - a material for subbase/base course in pavements  

Energy Technology Data Exchange (ETDEWEB)

The huge quantity of flyash accumulated over the years presents a colossal problem of disposal and environmental pollution. As a pozzolana, flyash has many advantages over other waste materials and can be successfully used in the lower layers of road pavements. Utilisation of flyash in India is extremely low compared to other countries. Results of various studies undertaken at the University of Roorkee on the use of flyash in road construction are described. Various aspects responsible for its low utilisation are examined and the appropriate solution suggested. 10 refs., 1 fig., 5 tabs.

Mehndiratta, H.C.; Chandra, S. [University of Roorkee, Roorkee (India). Civil Engineering Dept.

1996-12-31

219

Design Basis for Fibre Reinforced Concrete (FRC) Pavements  

DEFF Research Database (Denmark)

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

Bendixen, SØren; Stang, Henrik

1996-01-01

220

Potential for localized groundwater contamination in a porous pavement parking lot setting in Rhode Island  

Science.gov (United States)

The control of polluted surface runoff and the assessment of possible impacts on groundwater is a concern at the local and regional scale. On this background, a study investigates possible impacts of organic and inorganic pollutants (including bacteria) originating from a permeable asphalt parking lot on the water quality immediately beneath it. The functioning of the permeable pavement, including clogging and restricted vertical percolation, was also evaluated. Four nested sample ports (shallow and deep) were installed below low- and high-traffic areas, including one port outside the parking lot. At least initially there was a good hydraulic connection between the parking surface and the shallow sample ports. The presence of a geotextile layer at the base of the parking lot structure, however, was identified in lab tests as one factor restricting vertical percolation to the deeper ports. Clogging of the permeable surface was most pronounced in heavy traffic areas and below snow pile storage areas. Corroborated by high electric conductivity and chloride measurements, sand brought in by cars during winter was the principal cause for clogging. No bacteria or BOD were found in percolating water. Polycyclic aromatic hydrocarbons (PAH) were present at concentrations near minimum detection limit. Nutrients (nitrate and phosphate) were being leached into the ground via the permeable parking lot surface at annual flux rates of 0.45 0.84 g/m2/year. A multi-species tracer test demonstrated a retention capacity of the permeable parking lot structure of >90% for metals and 27% for nutrients, respectively.

Boving, Thomas B.; Stolt, Mark H.; Augenstern, Janelle; Brosnan, Brian

2008-08-01

 
 
 
 
221

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

UK PubMed Central (United Kingdom)

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

O'Neill TA; Balks MR; López-Martínez J; McWhirter JL

2012-12-01

222

Estimation of carrying capacity of slag and gravel forest road pavements  

Directory of Open Access Journals (Sweden)

Full Text Available The objective of the study was to estimate the carrying capacity of forest roads with slag and gravel pavements. Deformation module and elastic deflection were used as characteristic parameters of road carrying capacity. There were 9 tested sections divided into set groups. All investigated sections were measured using VSS plate (29 measurements) and deflectometer (53 measurements). Averaged results of the measurements of specific pavements were introduced in the analysis. The present study proved that the carrying capacity of slag and gravel pavements defined according to mean module ME is insufficient. The largest (122.87 MPa) mean deformation module was detained for gravel pavement. Two slag pavements with significant constructional differences had very similar values of deformation modules 98.26 and 94.84 MPa. Taking maximum deformation modules ME into consideration, slag, gravel and gravel-broken-stone pavements comply with the requirements for low traffic intensity (ME=130–200 MPa). Only two-ply gravel pavements (about 25 cm thick) have the mean carrying capacity complying with the requirements of low traffic intensity.

Grzegorz Trzcinski; Sergiusz Kaczmarzyk

2006-01-01

223

Environmental life-cycle cost analysis of asphalt and concrete pavements  

Energy Technology Data Exchange (ETDEWEB)

Large infrastructure projects in the world require life-cycle cost analysis as part of decision-making processes. The authors analysed the economic costs, energy requirements and greenhouse gas emissions related to pavement construction beginning with materials extraction to the end of the pavement life. They compared concrete versus asphalt. A pavement project consists of five specific steps: (1) new material extraction, (2) manufacturing of raw materials such as asphalt bitumen and cement, (3) production of pavement materials such as asphalt concrete and concrete, (4) pavement construction, and (5) pavement/facility operation, maintenance and rehabilitation. Factors such as the use of natural resources, air and water pollution, noise and land disruption, energy requirements and greenhouse gas emissions were considered. It was concluded that the manufacturing of cement requires high heat which releases carbon dioxide (CO{sub 2}). Concrete pavement proved to have lower total present worth costs for high traffic facilities while the same was true for asphalt and low and medium traffic facilities. The energy requirements were greater for the manufacturing of asphalt. Concrete exhibited a higher global warming potential in all cases studied, but this potential was greatly reduced with a 5 per cent reduction in fuel consumption for low traffic facilities. In the case of high traffic facilities, the global warming potential of concrete was negligible when considering any significant reduction in fuel consumption. 8 refs., 11 tabs.

Pontarollo, J. [Dufferin-Custom Concrete Group, Concord, ON (Canada); Hooton, D.; Byer, P. [Toronto Univ., ON (Canada). Dept. of Civil Engineering

2000-07-01

224

Incidence of respiratory distress syndrome  

International Nuclear Information System (INIS)

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

2003-01-01

225

Incidence of respiratory distress syndrome.  

UK PubMed Central (United Kingdom)

OBJECTIVE: To determine the incidence of respiratory distress syndrome (RDS) in hospital born babies. DESIGN: A prospective study. PLACE AND DURATION OF STUDY: The study was conducted in the neonatal intensive care unit (NICU) at the Pediatric department, in collaboration with the Obstetrics and Gynecology Department, Military Hospital, Rawalpindi, over a period of one year from January to December 2000. SUBJECTS AND METHODS: All live born infants delivered at the hospital and who fulfilled the diagnostic criteria of respiratory distress syndrome (RDS) were included in the study. RESULTS: Ninety-four neonates developed RDS. Out of these, 88 (93.61%) were preterm and 06 (6.38%) were term infants. There was a male preponderance (65.95%). RDS was documented in 1.72% of total live births, 37.28% of preterm and 0.11% of term neonates born at the hospital. The incidence of RDS was 100% at 26 or less weeks of gestation, 57.14% at 32 weeks, and 3.70% at 36 weeks. The mortality with RDS was 41 (43.61%). CONCLUSION: RDS is the commonest cause of respiratory distress in the newborn, particularly, in preterm infants. It carries a high mortality rate and the incidence is more than that documented in the Western world.

Ghafoor T; Mahmud S; Ali S; Dogar SA

2003-05-01

226

Simple manhole innovation cuts frost heave in pavement  

Energy Technology Data Exchange (ETDEWEB)

A method to prevent pavement from heaving and cracking around manholes has been developed by the National Research Council's Institute for Research in Construction (IRC). The simple method harnesses and uses the natural warmth of the water flowing through the storm and sanitary sewers to protect the soil around the manhole from frost. The heat from the sewers is harnessed by changing the design of the manhole by plugging the holes and adding a layer of insulation under the cover. The soil surrounding the manhole is also altered by placing large crushed stones around the manhole to help dissipate heat in all directions around the manhole. IRC has successfully carried out field tests with engineers in Ottawa. Their test manholes remained flat and free of cracks even after a winter of fluctuating temperatures and de-icing salt. The cost for the entire installation procedure is just slightly more than conventional manhole construction, but considering that the life of the pavement can be extended, municipalities can retrieve their investment. Secondary benefits include environmental benefits derived by less traffic disruption, less damage to vehicles, less material and fewer emissions. 3 figs.

Svec, O.J.

2000-03-31

227

A System for Road Pavement Composite Material Deformation  

Directory of Open Access Journals (Sweden)

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

2012-01-01

228

Finite Element Investigation of the Deterioration of Doweled Rigid Pavements  

CERN Multimedia

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...

Ghauch, Ziad G

2011-01-01

229

Sustainable Drainage Practices in Spain, Specially Focused on Pervious Pavements  

Directory of Open Access Journals (Sweden)

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.

Daniel Castro-Fresno; Valerio Carlos Andrés-Valeri; Luis Angel Sañudo-Fontaneda; Jorge Rodriguez-Hernandez

2013-01-01

230

Long-term salt marsh recovery and pavement persistence at {sup M}etula' spill sites  

Energy Technology Data Exchange (ETDEWEB)

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

Owens, E. H. [Polaris Applied Sciences, Bainbridge Island, WA (United States); Sergy, G. A. [Environment Canada, Edmonton, AB (Canada); Guzman, M. L. [Instituto de Fomento Pesquero, Punta Arenas (Chile); Wang, Z. [Environment Canada. Ottawa, ON (Canada); Baker, J. [Ruyton-XI-Towns (United Kingdom)

1999-07-01

231

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

Directory of Open Access Journals (Sweden)

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

Nur Izzi Md. Yusof; Amiruddin Ismail; Rosli Hainin; Hasanan Md Nor; Khairul Anwar Husin

2009-01-01

232

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

Directory of Open Access Journals (Sweden)

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

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

2011-01-01

233

Respiratory Distress Syndrome and its Complications  

Directory of Open Access Journals (Sweden)

Full Text Available Respiratory distress syndrome in premature babies is one of the most common and most important health problems in newborns. Respiratory distress syndrome of newborn is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural immaturity in the lungs. Respiratory distress syndrome begins shortly after birth and is manifest by tachypnea, tachycardia, chest wall retractions, expiratory grunting, nasal flaring and cyanosis during breathing efforts. Respiratory distress syndrome or complications caused by respiratory distress syndrome are the most important causes of mortality and morbidity in premature infants. This article briefly reviews respiratory distress syndrome and its complications. [Archives Medical Review Journal 2013; 22(4.000): 615-630

Eren Kale Cekinmez; Hacer Yapicioglu Yildizdas; Ferda Ozlu

2013-01-01

234

Development of Knowledge-Based Expert System for Flexible Pavement Design  

Directory of Open Access Journals (Sweden)

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

Deprizon; Amiruddin; Riza Atiq

2009-01-01

235

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

Science.gov (United States)

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.

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

2013-09-01

236

The use of accelerometers in the pavement performance monitoring and analysis  

International Nuclear Information System (INIS)

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

2010-06-01

237

Porous Pavement for Control of Highway Run-Off (Final Report).  

Science.gov (United States)

In 1986, the Arizona Department of Transportation (ADOT) constructed a 3500-foot porous pavement experimental section on SR-87 in the Phoenix metropolitan area. The objectives of the project were to determine the constructibility and subsequent performanc...

M. Hossain L. A. Scofield

1991-01-01

238

Calibration and Validation of the Enhanced Integrated Climatic Model for Pavement Design.  

Science.gov (United States)

This report summarizes the results of research to evaluate, calibrate, and validate the Enhanced Integrated Climatic Model (EICM) incorporated in the original Version 0.7 (July 2004 release) of the Mechanistic-Empirical Pavement Design Guide (MEPDG) softw...

C. E. Zapata W. N. Houston

2008-01-01

239

Permeable Pavement Research at NRMRLâ??s Urban Watershed Research Facility (Poster 2)  

Science.gov (United States)

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

240

Monitoring of the Permeable Pavement Demonstration Site at the Edison Environmental Center (Poster)  

Science.gov (United States)

This is a poster on the permeable pavement parking lot at the Edison Environmental Center. The monitoring scheme for the project is discussed in-depth with graphics explaining the instrumentation installed at the site. ...

 
 
 
 
241

Evaluation of Risk in End-Result Specifications for Asphalt Pavement Construction.  

Science.gov (United States)

End-Result Specifications (ERS) for asphalt pavement construction offer potential benefits over method-related specifications. They can be used in conjunction with or replacement of traditional QC/QA specifications as a means to enhance contractor innovat...

A. Manik W. G. Buttlar

2007-01-01

242

Relationship of Air Voids, Lift Thickness, and Permeability in Hot Mix Asphalt Pavements.  

Science.gov (United States)

This report presents recommended guidelines for hot mix asphalt pavement construction to achieve satisfactory levels of in-place air voids and permeability. These guidelines were developed from the findings of a research project that examined the relation...

E. R. Brown M. R. Hainin A. Cooley G. Hurley

2004-01-01

243

Pavement Management Applications Using Geographic Information Systems. A Synthesis of Highway Practice.  

Science.gov (United States)

This report of the Transportation Research Board documents the state of the practice and knowledge of pavement management systems (PMS) using Geographic Information Systems (GIS) and other spatial technologies and discusses how the technologies have been ...

G. W. Flintsch R. Dymond J. Collura

2004-01-01

244

Distress screening in a multidisciplinary lung cancer clinic: prevalence and predictors of clinically significant distress.  

UK PubMed Central (United Kingdom)

Screening for distress in cancer patients is recommended by the National Comprehensive Cancer Network, and a Distress Thermometer has previously been developed and empirically validated for this purpose. The present study sought to determine the rates and predictors of distress in a sample of patients being seen in a multidisciplinary lung cancer clinic. Consecutive patients (N=333) were recruited from an outpatient multidisciplinary lung cancer clinic to complete the Distress Thermometer, an associated Problem Symptom List, and two questions about interest in receiving help for symptoms. Over half (61.6%) of patients reported distress at a clinically significant level, and 22.5% of patients indicated interest in receiving help with their distress and/or symptoms. Problems in the areas of family relationships, emotional functioning, lack of information about diagnosis/treatment, physical functioning, and cognitive functioning were associated with higher reports of distress. Specific symptoms of depression, anxiety, pain and fatigue were most predictive of distress. Younger age was also associated with higher levels of distress. Distress was not associated with other clinical variables, including stage of illness or medical treatment approach. Similar results were obtained when individuals who had not yet received a definitive diagnosis of lung cancer (n=134) were excluded from analyses; however, family problems and anxiety were no longer predictive of distress. Screening for distress in a multidisciplinary lung cancer clinic is feasible and a significant number of patients can be expected to meet clinical criteria for distress. Results also highlight younger age and specific physical and psychosocial symptoms as predictive of clinically significant distress. Identification of the presence and predictors of distress are the first steps toward appropriate referral and treatment of symptoms and problems that contribute to cancer patients' distress.

Graves KD; Arnold SM; Love CL; Kirsh KL; Moore PG; Passik SD

2007-02-01

245

High-temperature behaviour of heated floor pavements covered with ceramic tiles and plates, natural stone and concrete blocks. Zum Verhalten von beheizten Fussbodenkonstruktionen mit keramischen Fliessen und Platten, Naturstein und Betonwerkstein bei hoeheren Heiztemperaturen  

Energy Technology Data Exchange (ETDEWEB)

Heated floor pavements whose surface temperature should neither fall below 22/sup 0/C nor exceed 28/sup 0/C are making their way due to their promising an improved energy utilization and thermal comfort. However, unfavourable conditions may lead to surface temperatures up to 70/sup 0/C causing the formation of cracks or loosening of the flooring (ceramics, concrete blocks etc.). The study therefore investigates into the acceptable limit of the surface temperatures of heated floor pavements covered with rigid ceramic tiles or plates, natural stone and concrete blocks. Damage to the flooring is prevented by avoiding flow temepratures above 60/sup 0/C. The study reports on the set-up of tests, the measuring results and evaluation of measuring results.

Manns, W.; Zeus, K.

1986-01-01

246

A test of porous pavement effectiveness on clay soils during natural storm events.  

UK PubMed Central (United Kingdom)

Porous pavements allow precipitation to infiltrate through the pavement to the soil, reducing the volume of stormwater runoff produced at a site. However, porous pavements are not widely used on fine-grained soils due to concerns about their performance. Our objective was to investigate the efficacy of porous pavements in controlling stormwater runoff on clay soils. We compared the performance of an asphalt parking lot and a porous pavement parking lot of grass pavers in Athens, Georgia, USA, over relatively small and low-intensity rain events. The porous lot produced 93% less runoff than the asphalt lot. The total volume of runoff at the porous lot was significantly less than the asphalt lot (t = 2.96, p = 0.009). Turbidity was significantly greater at the asphalt lot (t = 6.18, p < 0.001) whereas conductivity was significantly higher at the porous lot (t = 2.31, p = 0.03). Metal and nutrient concentrations were below detection limits at both lots during seven of nine small storm events. During events in which we could detect pollutants, calcium, zinc, silica, and total phosphorus concentrations were higher at the asphalt lot whereas total nitrogen concentrations were greater at the porous lot. Our results suggest porous pavements are a viable option for reducing stormwater runoff and some pollutants from small storms or the first flush from large storms on clay soils.

Dreelin EA; Fowler L; Ronald Carroll C

2006-02-01

247

A test of porous pavement effectiveness on clay soils during natural storm events.  

Science.gov (United States)

Porous pavements allow precipitation to infiltrate through the pavement to the soil, reducing the volume of stormwater runoff produced at a site. However, porous pavements are not widely used on fine-grained soils due to concerns about their performance. Our objective was to investigate the efficacy of porous pavements in controlling stormwater runoff on clay soils. We compared the performance of an asphalt parking lot and a porous pavement parking lot of grass pavers in Athens, Georgia, USA, over relatively small and low-intensity rain events. The porous lot produced 93% less runoff than the asphalt lot. The total volume of runoff at the porous lot was significantly less than the asphalt lot (t = 2.96, p = 0.009). Turbidity was significantly greater at the asphalt lot (t = 6.18, p < 0.001) whereas conductivity was significantly higher at the porous lot (t = 2.31, p = 0.03). Metal and nutrient concentrations were below detection limits at both lots during seven of nine small storm events. During events in which we could detect pollutants, calcium, zinc, silica, and total phosphorus concentrations were higher at the asphalt lot whereas total nitrogen concentrations were greater at the porous lot. Our results suggest porous pavements are a viable option for reducing stormwater runoff and some pollutants from small storms or the first flush from large storms on clay soils. PMID:16426659

Dreelin, Erin A; Fowler, Laurie; Ronald Carroll, C

2006-01-19

248

Bitumen-cement Stabilized Layer in Pavement Construction Using Indirect Tensile Strength (ITS) Method  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, the objective was to blend and mix Portland cement and bitumen emulsion with soil for enhancing the strength, durability and pertinent properties of the soil. In order to enhance the soil strength and lessen its vulnerability to water, soil stabilization is required to be applied to the soil. In line with this, improved load transfer was added to the pavement foundation by having the cement effect which actually boosts the stiffness and Bitumen emulsion effects which improve resilience and soil permeability of the stabilized layer. The current study is divided into two phases. In the first phase, the optimization of Portland cement and bitumen emulsion was preformed as well as conducting a series of Indirect Tensile Strength (ITS). Furthermore, in order to lessen the pavement’s thickness and to enhance its bearing capacity, alternative roadway sections were scrutinized through the second phase. The results proved that soil stabilization with cement and bitumen enhances the bearing capacity of pavements in two chief areas. Primarily, there was enhancement in pavement’s lifetime and the more efficient construction time is achieved.

Mojtaba Shojaei Baghini; Amiruddin Ismail; Behnam Kheradmand; Mohamad Hesam Hafezi; Ramez Alezzi Almansob

2013-01-01

249

Distress in Older Patients With Cancer  

Science.gov (United States)

Purpose To determine the predictors of distress in older patients with cancer. Patients and Methods Patients age ? 65 years with a solid tumor or lymphoma completed a questionnaire that addressed these geriatric assessment domains: functional status, comorbidity, psychological state, nutritional status, and social support. Patients self-rated their level of distress on a scale of zero to 10 using a validated screening tool called the Distress Thermometer. The relationship between distress and geriatric assessment scores was examined. Results The geriatric assessment questionnaire was completed by 245 patients (mean age, 76 years; standard deviation [SD], 7 years; range, 65 to 95 years) with cancer (36% stage IV; 71% female). Of these, 87% also completed the Distress Thermometer, with 41% (n = 87) reporting a distress score of ? 4 on a scale of zero to 10 (mean score, 3; SD, 3; range, zero to 10). Bivariate analyses demonstrated an association between higher distress (? 4) and poorer physical function, increased comorbid medical conditions, poor eyesight, inability to complete the questionnaire alone, and requiring more time to complete the questionnaire. In a multivariate regression model based on the significant bivariate findings, poorer physical function (increased need for assistance with instrumental activities of daily living [P = .015] and lower physical function score on the Medical Outcomes Survey [P = .018]) correlated significantly with a higher distress score. Conclusion Significant distress was identified in 41% of older patients with cancer. Poorer physical function was the best predictor of distress. Further studies are needed to determine whether interventions that improve or assist with physical functioning can help to decrease distress in older adults with cancer.

Hurria, Arti; Li, Daneng; Hansen, Kurt; Patil, Sujata; Gupta, Ravi; Nelson, Christian; Lichtman, Stuart M.; Tew, William P.; Hamlin, Paul; Zuckerman, Enid; Gardes, Jonathan; Limaye, Sewanti; Lachs, Mark; Kelly, Eva

2009-01-01

250

Recall mammography and psychological distress.  

UK PubMed Central (United Kingdom)

BACKGROUND: The aims of this study were (a) to identify psychological distress before and after being diagnosed with or without cancer in women recalled for further investigation because previous screening mammography indicated possible malignancy and (b) to document the willingness to attend and recommend mammography. Study participants included 526 recalled women (82% response) who completed a questionnaire before the recall mammogram and 4 weeks after receiving the result. Psychological distress was measured using the Hospital Anxiety and Depression Scale. RESULTS: Most subjects were diagnosed without cancer (87.6% false-positive rate). Recall after mammography among women with a false-positive mammogram was associated with transiently increased anxiety and a slight increase in depression. However, the level of anxiety was similar to and the level of depression was lower than in the general female Norwegian population. Women who received a cancer diagnosis had higher levels of anxiety and depression than the general female Norwegian population. Nearly all women (99%) were satisfied with their participation in the screening programme; 94% thought it was important, 98% would attend the next round of screening and 99% would recommend other women to attend. CONCLUDING STATEMENT: Recall after mammography was associated with transiently increased anxiety. Four weeks after screening, the level of anxiety was the same and depression was lower compared with the general female Norwegian population. The women were almost unanimously satisfied with their participation in the screening, would participate again and would recommend other women to participate.

Schou Bredal I; Kåresen R; Skaane P; Engelstad KS; Ekeberg Ø

2013-03-01

251

[Moral distress in nursing care].  

UK PubMed Central (United Kingdom)

In nursing practice, the ability to make decisions regarding patients and to act on them is considered to be an expression of the professional nursing role. Problems may arise when a nurses would like to perform an action they believe morally correct but which are conflictual with the habits, organization or politics of the health structure in which they work. This inevitably produces moral distress in nurses who feel impotent to act as they feel they should. Although a certain amount of moral distress is part and parcel of the nursing profession , when it is excessive or prolonged it may become unacceptable and culminate in burn-out and the relative consequences. The aim of the study was to compare the level of moral stress in 111 Italian nurses working in different Operative Units to identify those clinical situations significantly associated with moral stress using the MDS scale. Similarly to studies performed in the USA, the level of moral stress in the 3 different work contexts was moderate, although some clinical situations were related to significant stress levels.

Negrisolo A; Brugnaro L

2012-07-01

252

DESERT PAVEMENTS AND SOILS ON BASALTIC PYROCLASTIC DEPOSITS AT LATHROP WELLS AND RED CONE VOLCANOES, SOUTHERN NEVADA  

Energy Technology Data Exchange (ETDEWEB)

Formation of desert pavement and accretionary soils are intimately linked in arid environments such as the Mojave Desert. Well-sorted fallout scoria lapilli at Lathrop Wells (75-80 ky) and Red Cone ({approx}1 Ma) volcanoes (southern Nevada) formed an excellent starting material for pavement, allowing infiltration of eolian silt and fine sand that first clogs the pore space of underlying tephra and then aggrades and develops vesicular A (Av) horizons. Variations in original pyroclast sizes provide insight into minimum and maximum clast sizes that promote pavement and soil formation: pavement becomes ineffective when clasts can saltate under the strongest winds, while clasts larger than coarse lapilli are unable to form an interlocking pavement that promotes silt accumulation (necessary for Av development). Contrary to predictions that all pavements above altitudes of {approx}400 m would have been ''reset'' in their development after late Pleistocene vegetation advances (about 15 ka), the soils and pavements show clear differences in maturity between the two volcanoes. This indicates that either the pavement soils develop slowly over many 10,000's of years and then are very stable, or that, if they are disrupted by vegetation advances, subsequent pavements are reestablished with successively more mature characteristics.

G.A. Valentine; C.D. Harrington

2005-08-10

253

Interpersonal relationships and emotional distress in adolescence.  

UK PubMed Central (United Kingdom)

The aim of this study was to examine positive and negative qualities in adolescents' interpersonal relationships and their relative importance in predicting emotional distress. Participants were 260 students from three schools in the Dublin area (119 girls; 141 boys), aged 12-18 years (M = 15.32, SD = 1.91). Students completed questionnaires assessing qualities in important interpersonal relationships in their lives and emotional distress. Girls reported more positive qualities in their relationships with mothers and best friends than boys. Younger students reported more positive qualities in their relationships with parents than older students. Stepwise multiple regression analysis revealed high levels of satisfaction in interpersonal relationships were predictive of low levels of emotional distress whereas high levels of criticism and exclusion were predictive of high levels of distress. High levels of support and disclosure were also linked to emotional distress. These findings and their implications are discussed in detail.

Kenny R; Dooley B; Fitzgerald A

2013-04-01

254

Insight, distress and coping styles in schizophrenia.  

UK PubMed Central (United Kingdom)

BACKGROUND: The stigma and negative societal views attached to schizophrenia can make the diagnosis distressing. There is evidence that poor insight into symptoms of the disorder and need for treatment may reflect the use of denial as a coping style. However, the relationships between insight and other coping styles have seldom been investigated. METHOD: We examined the associations between insight, distress and a number of coping styles in 65 outpatients with schizophrenia (final n=57) in a cross-sectional study. RESULTS: We found that (i) awareness of symptoms and problems correlated with greater distress, (ii) 'preference for positive reinterpretation and growth' coping style correlated with lower distress and with lower symptom awareness (re-labelling), (iii) 'preference for mental disengagement' coping style correlated with greater distress and lower awareness of problems, and (iv) 'social support-seeking' coping style correlated with greater awareness of illness, but not distress. No relationship occurred between the use of 'denial' as a coping style and insight or distress. CONCLUSIONS: Our findings demonstrate that awareness of illness and related problems is associated with greater distress in schizophrenia. However, this investigation has not supported a simple psychological denial explanation for this relationship, as complex relationships emerged between different dimensions of insight and coping styles. The negative association between 'positive reinterpretation and growth' and distress suggests that adopting this style may lead to re-labelling symptoms in a less distressing way. Avoidant and isolating styles of coping both appear unhelpful. Psychological interventions should aim to promote more active coping such as discussing a mental health problem with others.

Cooke M; Peters E; Fannon D; Anilkumar AP; Aasen I; Kuipers E; Kumari V

2007-08-01

255

Pathology Case Study: Respiratory Distress  

Science.gov (United States)

This cardiovascular pathology case study, provided by the University of Pittsburgh Department of Pathology, is an excellent resource for students and instructors in the health science fields. A 72-year-old female experiencing respiratory distress is the focus of this case. The patientâÂÂs history, gross description, and microscopic description of test results are provided to aid readers in understanding the patientâÂÂs diagnosis. The official final diagnosis is accompanied by a discussion of the contributing doctorâÂÂs findings and a list of references. This is an excellent resource for students in the health sciences to familiarize themselves with using patient history and laboratory results to diagnose patientâÂÂs conditions.

Ariyanayagam-Baksh, Shashi

2009-05-07

256

YOUTH UNEMPLOYMENT AND PHYSICAL DISTRESS  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, an effort has been made to investigate the role of unemployment in the development of the physical distress in youth. A sample of 400 subjects (200 males and 200 females) was drawn randomly from Shimla district of Himachal Pradesh. Comparison was done between unemployed and employed youth in both the gender groups i.e. males and females. A 2 x 2 ANOVA has yielded significant results that unemployed people had significantly perceived poor physical health profiles (eyes and ears, respiratory system, cardiovascular system, digestive tract, musculoskeletal system, skin, nervous system, genitourinary system, fatigability, frequency of illness, miscellaneous diseases, habits) than employed people. Findings from this study suggest that the impetus for unemployment be it voluntary or involuntary, may significantly impact a person's physical health.

ANITA SHARMA

2013-01-01

257

Moss cushions facilitate water and nutrient supply for plant species on bare limestone pavements  

DEFF Research Database (Denmark)

Dense moss cushions of different size are distributed across the bare limestone pavements on Øland, SE Sweden. Increasing cushion size is predicted to physically protect and improve performance and colonization by vascular plants. Therefore, we tested water balance, phosphorus supply, and species richness, and evaluated duration of plant activity during desiccation as a function of ground area, for a large collection of moss cushions. We found that lower evaporation and higher water storage contributed equally to extending the desiccation period with increasing cushion size. Evaporation rates declined by the -0.36 power of cushion diameter, and were not significantly different from -0.50 for the square root function previously predicted for the increasing thickness of the boundary layer, with greater linear dimensions for smooth flat objects at low wind velocities. Size dependence vanished under stagnant conditions. One moss species was added to the species pool for every nine-fold increase in cushion area. Vascular plants were absent from the smallest cushions, whereas one or two species, on average, appeared in 375- and 8,500-cm(2) cushions with water available for 6 and 10 days during desiccation. Phosphorus concentrations increased stepwise and four-fold from detritus to surface mosses and to vascular plants, and all three pools increased with cushion size. We conclude that cushion mosses and cushion size play a critical role in this resource-limited limestone environment by offering an oasis of improved water and nutrient supply to colonization and growth of plants.

Jensen, Kaj Sand; Hammer, Kathrine

2012-01-01

258

Crumb rubber modifier (CRM) in asphalt pavement: Summary of practices in Arizona, California, and Florida. Interim report, 1 February-30 June 1995  

Energy Technology Data Exchange (ETDEWEB)

Highway agencies have been evaluating crumb rubber modifier (CRM) in hot mix asphalt (HMA) since the 1970`s. Three agencies, Arizona, California, and Florida, currently use CRM in HMA at levels that would approach or exceed the mandate in Section 1038 of the Intermodal Surface Transportation Efficiency Act of 1991. This report documents the use of CRM in HMA in these three States. In particular, it addresses issues including thickness design, materials and mix design, construction procedure, including control, and pavement performance. The report also addresses the following questions: (1) What processes are used, (2) Why are they used, (3) How are they performing.

Hicks, R.G.; Lundy, J.R.; Leahy, R.B.; Hanson, D.; Epps, J.

1995-09-01

259

Predictors of distress and anxiety during pregnancy.  

UK PubMed Central (United Kingdom)

OBJECTIVE: There is a high incidence of distressing psychological symptoms including anxiety in pregnancy. Nevertheless, predictors of distress and anxiety during pregnancy have not been well characterized. We determined whether temperament and character, trait anxiety, resilience, and social support predicted distress and anxiety symptoms in pregnancy. METHOD: Pregnant women (n=105) with low risk singleton pregnancies were recruited from Midwife Obstetric Units. Assessments of distress (using the K-10) and anxiety (using the Spielberger State Inventory) were undertaken in trimester 2 and 3. Measures of temperament and character, trait anxiety, resilience and social support were undertaken at the same time points. Regression analyses were used to determine predictors of distress and anxiety at each trimester. RESULTS: Predictors of distress and anxiety were lower selfdirectedness, higher harm avoidance, higher trait anxiety, lower resilience, and lower social support, at each time point. CONCLUSION: Understanding predictors of distress and anxiety in pregnancy may be useful in developing interventions for addressing such symptoms, as well as perhaps in preventing potential sequelae such as anxiety and mood disorders.

Roos A; Faure S; Lochner C; Vythilingum B; Stein DJ

2013-03-01

260

Moral Distress in Medical Education and Training.  

UK PubMed Central (United Kingdom)

Moral distress is the experience of cognitive-emotional dissonance that arises when one feels compelled to act contrary to one's moral requirements. Moral distress is common, but under-recognized in medical education and training, and this relative inattention may undermine educators' efforts to promote empathy, ethical practice, and professionalism. Moral distress should be recognized as a feature of the clinical landscape, and addressed in conjunction with the related concerns of negative role modeling and the goals and efficacy of medical ethics curricula.

Berger JT

2013-10-01

 
 
 
 
261

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

Directory of Open Access Journals (Sweden)

Full Text Available The paperproducing industry generates various wastes coming out from the various processes. From the preliminary waste named as hypo sludge, due to its low calcium is taken out to replace the cement in concrete. Major initiatives are needed in India to use these large volumes in construction industry especially in rigid pavement construction and other infrastructure projects. Moreover Use of Hypo Sludge in construction of rigid pavement will improve transportation functionality and ecological sustainability and results in improved traffic safety and reduced life-cycle cost. Use of Hypo Sludge in construction of rigid pavement will benefit urban growth, public health and surrounding communities by encouraging smart growth by integrating and guiding future growth. It is also needed to reduce the cost of concrete pavement for rural development in India. So our study is concerned with eco-efficient utilization of Hypo sludge as partial replacement of cement in concrete for development of low cost rigid pavement of rural road infrastructure.The Hypo sludge was replaced within the range of 10-40% by weight of cement. In the present study, 5 different mixes of Hypo Sludge are tested for parameters like: compressive strength, flexural strength and cost

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

2013-01-01

262

The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring - Slides  

Science.gov (United States)

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

263

The Edison Environmental Center Permeable Pavement Site: Initial Results from a Stormwater Control Designed for Monitoring - Paper  

Science.gov (United States)

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

264

Life cycle assessment of representative swiss road pavements for national roads with an accompanying life cycle cost analysis.  

UK PubMed Central (United Kingdom)

The subject of this paper is an environmental life cycle assessment (LCA) and life cycle cost analysis (LCCA) of processes needed to construct and maintain representative Swiss asphalt, concrete, and composite pavements (including subbase layers) applicable for the Swiss national road network over a period of 75 years. The environmental indicators analyzed are the global warming potential indicator, the nonrenewable cumulative energy demand, and the Swiss ecological scarcity indicator. Processes of the use phase of the road (fuel consumption, noise, etc.) have been evaluated qualitatively based on intensive research. The study shows that the global warming potential of concrete and asphalt pavements equilibrates over the analysis period and that concrete pavements compared to asphalt and composite pavements offer advantages in regards to the nonrenewable cumulative energy demand, the ecological scarcity indicator, and life cycle costs. The qualitative evaluation of the processes of the use phase shows for example the positive qualities of concrete pavements regarding fuel consumption and permanent noise properties.

Gschösser F; Wallbaum H

2013-08-01

265

Prediction of Airport Flexible Pavement Critical Responses from Non-destructive Test Data Using ANN-based Structural Models  

Directory of Open Access Journals (Sweden)

Full Text Available This study describes the development of Artificial Neural Network (ANN) based pavement response prediction models for rapid structural analysis of airport flexible pavements based on Non-destructive Test (NDT) data. A finite element based pavement structural model, which can accommodate stress-sensitive geomaterial stiffness models, was used to generate the ANN training and testing dataset. The goal was to establish ANN models for predicting critical responses (stresses and strains) from routine NDT airfield pavement structural evaluation data. The developed ANN models predicted the critical pavement responses obtained from the finite element model with good accuracy. Further research is required to achieve increased prediction accuracies and validate the ANN models using actual field data.

Kasthurirangan Gopalakrishnan

2006-01-01

266

Life cycle assessment of representative swiss road pavements for national roads with an accompanying life cycle cost analysis.  

Science.gov (United States)

The subject of this paper is an environmental life cycle assessment (LCA) and life cycle cost analysis (LCCA) of processes needed to construct and maintain representative Swiss asphalt, concrete, and composite pavements (including subbase layers) applicable for the Swiss national road network over a period of 75 years. The environmental indicators analyzed are the global warming potential indicator, the nonrenewable cumulative energy demand, and the Swiss ecological scarcity indicator. Processes of the use phase of the road (fuel consumption, noise, etc.) have been evaluated qualitatively based on intensive research. The study shows that the global warming potential of concrete and asphalt pavements equilibrates over the analysis period and that concrete pavements compared to asphalt and composite pavements offer advantages in regards to the nonrenewable cumulative energy demand, the ecological scarcity indicator, and life cycle costs. The qualitative evaluation of the processes of the use phase shows for example the positive qualities of concrete pavements regarding fuel consumption and permanent noise properties. PMID:23865779

Gschösser, Florian; Wallbaum, Holger

2013-07-18

267

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.

2010-05-01

268

Cytokinin signaling regulates pavement cell morphogenesis in Arabidopsis.  

UK PubMed Central (United Kingdom)

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.

Li H; Xu T; Lin D; Wen M; Xie M; Duclercq J; Bielach A; Kim J; Reddy GV; Zuo J; Benková E; Friml J; Guo H; Yang Z

2013-02-01

269

Education and psychological distress among older Chinese.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The goal of this research is to see if more highly educated older Chinese have lower levels of distress than do their poorly educated counterparts and whether engaging in cognitively stimulating activities such as reading and playing mahjong explains the association. METHOD: Using the Chinese Healthy Longevity Survey, the authors find a significant negative association between education and psychological distress. Much of the association is mediated by activities, but not all in the ways expected. Reading, playing mahjong, and watching television all negatively correlate with distress. DISCUSSION: Better-educated older Chinese have lower levels of distress than do their less-well-educated counterparts in part because they engage in cognitively stimulating activities, have better economic circumstances, and engage in more physical activity.

Ross CE; Zhang W

2008-04-01

270

Measuring Run-Off Dynamics from Pavements using the Weighable Tipping Bucket  

Science.gov (United States)

Due to climate change, cities need to adapt to changing rainfall and rainwater run-off dynamics. In order to get an appropriate data base for an corresponding process based water balance model for pavements, we had to improve the measuring method for urban run-off dynamics. We tinkered an old tipping bucket to a digital balance, called that a weighable tipping bucket (WTB) and were able to measure run-off from our paved lysimeters with an substantially increased temporal and volume resolution. Traditional tipping buckets (TB) have a volume resolution, capable to quantify the highest intensities in a range of expected flows. This results in varying temporal resolutions for varying flow intensities, especially in low resolutions for small flow events. Therefore, their applicability for run-off measurements and other hydrological process studies is limited, especially when dynamics of both small and storm events shall be described. This paper introduces the device set up and an according data processing concept. The improved volume and temporal resolution of the WTB are demonstrated. The impact of that increased resolution on our understanding of run-off dynamics from paved urban soils are discussed, exemplary for the run-off and the surface storage of a paved urban soil. The study was conducted on a permeably paved lysimeter situated in Berlin, Germany. Referring to the paved surface, the TB has a resolution of 0.1 mm, while the WTB has a resolution of 0.0005 mm. The temporal resolution of the WTB is 3 s, the TB detects individual tippings with 0.4 s between them. Therefore, the data processing concept combines both the benefits of the balance and the TB. During a five months period (July to November 2009) 154 rain events were detected. Accordingly, the TB and WTB detected 47 and 121 run-off events. The total run-off was 79.6mm measured by the WTB which was 11% higher than detected by the TB. 95% of that difference can be appointed to water, which evaporated from the TB. To derive a surface storage estimation, we analyzed the WTB and TB data for rain events without run-off. According to WTB data, the surface storage of the permeable pavement is 1.7 mm, while using TB data leads to an overestimation of 47% due to low volume resolution of the TB. Combining traditional TB with modern, fast, high resolution digital balances offers the opportunity to upgrade existing TB systems in order to improve their volume detection limit and their temporal resolution, which is of great advantage for the synchronization of water balance component measurements and the investigation of hydrological processes. Details can be found in Hydrol. Earth Syst. Sci., 15, 1379-1386, 2011 www.hydrol-earth-syst-sci.net/15/1379/2011/ doi:10.5194/hess-15-1379-2011

Nehls, T.; Rim, Y. N.; Wessolek, G.

2012-04-01

271

Dysphoric distress in childbearing women.  

Science.gov (United States)

Previous research on depression in childbearing women has focused on the presence or absence of clinical depression. Little attention has been paid to the distress caused by the presence of depressive symptoms in the absence of the full syndrome of clinical depression. A convenience sample of 202 healthy, married, primigravid women who were free of psychiatric symptoms were assessed at 10 to 14 weeks and 30 to 32 weeks of pregnancy and at 1 to 2 weeks and 14 weeks post partum. Depression symptoms were measured by using the Schedule of Affective Disorders and Schizophrenia, the standardized clinical interview for research and depression of The National Institute of Mental Health. Data from the Schedule of Affective Disorders and Schizophrenia indicated that only 5% of the women met criteria for clinical depression but approximately 50% of the sample reported clinical levels of three or more depressive symptoms. Anger, fatigue, psychic anxiety, and worry were the most frequently endorsed symptoms at each assessment point. The implications of these findings for symptom management and health promotion for childbearing women are discussed. PMID:1479458

Affonso, D D; Lovett, S; Paul, S; Sheptak, S; Nussbaum, R; Newman, L; Johnson, B

1992-12-01

272

Plastic Damage Model to Evaluate the Fracture Size of Semi-Rigid Base Pavement  

Directory of Open Access Journals (Sweden)

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.

Cao Peng; Feng Decheng; Jing Ruxin; Zhao Yin

2013-01-01

273

Rehabilitation of concrete pavements; Concrete hoso no hoshu koho ni kansuru kento  

Energy Technology Data Exchange (ETDEWEB)

The overlay methods being main rehabilitation of concrete pavement as an object of heavy load were divided into three types of adhesive overlay, direct overlay and separable overlay according to boundary state between existing concrete and overlay. In this study, overlay technology was investigated as follows by cement concrete using concrete pavement: as a results of reference investigation and questionnaire investigation to pavement companies, it is showed that adhesive overlay with a thin layer is a main one, this technology is desirably established. The mechanical theory on a design method of thick overlay for adhesive, direct and separable type was examined based on historic detail of development. Concerning to adhesive overlay, force equilibrium of a structure was considered, shear stress below an overlay layer due to wheel load, temperature change, dried shrink was considered by an analysis model and the finite element method. 9 figs., 2 tabs.

Fukute, T. [Port and Harbour Research Inst., Yokosuka (Japan)

1995-11-10

274

Maternal hurricane exposure and fetal distress risk.  

UK PubMed Central (United Kingdom)

Logistic regression and spatial analytic techniques are used to model fetal distress risk as a function of maternal exposure to Hurricane Andrew. First, monthly time series compare the proportion of infants born distressed in hurricane affected and unaffected areas. Second, resident births are analyzed in Miami-Dade and Broward counties, before, during, and after Hurricane Andrew. Third, resident births are analyzed in all Florida locales with 100,000 or more persons, comparing exposed and unexposed gravid females. Fourth, resident births are analyzed along Hurricane Andrew's path from southern Florida to northeast Mississippi. Results show that fetal distress risk increases significantly with maternal exposure to Hurricane Andrew in second and third trimesters, adjusting for known risk factors. Distress risk also correlates with the destructive path of Hurricane Andrew, with higher incidences of fetal distress found in areas of highest exposure intensity. Hurricane exposed African-American mothers were more likely to birth distressed infants. The policy implications of?in utero?costs of natural disaster exposure are discussed.

Zahran S; Snodgrass JG; Peek L; Weiler S

2010-10-01

275

Couple distress after localised prostate cancer.  

UK PubMed Central (United Kingdom)

BACKGROUND: The experience of the diagnosis of prostate cancer is distressing for both men and their partners. The present study describes the prevalence of psychological distress in men with prostate cancer and their partners, and the predictors of adjustment outcomes. METHODS/DESIGN: A cross-sectional survey of 189 prostate cancer patients who were scheduled for or had undergone surgery for localised prostate cancer and their partners assessed socio-demographic variables, masculine self-esteem and social intimacy, psychological adjustment and quality of life. RESULTS: Overall, patients and partners reported low distress; however, female partners were more anxious with 36 % reporting mild to severe anxiety. For men, masculine self-esteem and time since diagnosis were most strongly related to mental health status; urinary bother most influenced physical quality of life. For female partners, the man's psychological distress and his sexual bother were most strongly related to her mental health status; higher social intimacy was most strongly associated with physical quality of life. CONCLUSION: The correlates of distress after the diagnosis of prostate cancer differ between patients and female partners. For men, masculine self-esteem may be most crucial, whereas for women, her partner's level of distress may matter most. Research to better understand these interactions is needed.

Chambers SK; Schover L; Nielsen L; Halford K; Clutton S; Gardiner RA; Dunn J; Occhipinti S

2013-06-01

276

[Exploring moral distress among clinical nurses].  

UK PubMed Central (United Kingdom)

Moral distress in nursing practice is described as a suffering situation that arises when the nurse is unable to act her/his ethical choices, when institutional constraints interfere with acting in the way she/he believes to be right. The aim is to describe nursing practice situations causing moral distress resulting from the recognition of the ethical appropriate actions combined with the impossibility to pursue it; to describe how nurses manage moral distress situations and the strategies to cope with them. A focus group was conducted in three wards of a large teaching-hospital in the north of Italy. In another ward the nurses were asked to write a moral distress experience. A total of 40 nurses were involved and 50 experiences collected. The experiences' analysis has shown 5 source areas of moral distress: 1) clinical decision; 2) nursing competences; 3) nurse-physician collaboration; 4) organization of care; 5) safe care. For each area the most frequent themes were highlighted.Areas of clinical decision, nursing competences, nurse-physician collaboration involve nurse leaders in identification and implementation of strategies for managing moral distress.

Lovato S; Lovato L; Cunico L

2012-07-01

277

Airport pavement and concrete. Part 1. ; Economic comparisons of pavement by present worth method. Kuko hoso to concrete 1. ; Kuko ni okeru asphalt hoso to concrete hoso no keizai hikaku  

Energy Technology Data Exchange (ETDEWEB)

With the objectives of fostering concrete pavement in airport construction and improving pavement techniques as well as techniques related thereto, Cement Association, Japan formed Committee on Airport Pavement Research in October, 1986 which, in turn, formed three working groups to carry out investigation and research on urgent issues. One of such issues was economic comparisons between asphalt and concrete in airport construction and investigations were conducted for three years from 1986 fiscal year. This article is its report. Concerning economic comparisons, reliable quantitative comparisons must be made. Hence, first of all, in order to investigate the actual situations of breakages of airport pavement with regard to asphalt and concrete respectively, enquiries were made to the two typical airports in Japan on their maintenance and repair histories as well as the expenses therefor, and document investigations on costs for maintenance and repair of pavement were conducted. Based thereupon, economic comparisons of the two kinds of airport pavement were made by model analysis using the present worth method. As a result, it was found that economy of concrete pavement was superior to that of asphalt. 12 refs., 13 figs., 3 tabs.

1990-06-01

278

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

Science.gov (United States)

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

Plati, Christina; Georgiou, Panos; Loizos, Andreas

2013-04-01

279

Dual-function growth medium and structural soil for use as porous pavement.  

UK PubMed Central (United Kingdom)

Permeable grass-covered surfaces can reduce the quantity of storm water runoff and filter out potentially harmful chemicals. The objective of this study was to develop permeable structural soils that sustained healthy turf growth and filtered heavy metals from contaminated pavement runoff. The basic soil medium was a 50:50 mixture (v/v) of expanded shale (ExSh) and quartz sand (QS). The ExSh component consisted of (i) large-diameter particles (3-6 mm), (ii) small-diameter particles (1-3 mm), or (iii) a 50:50 mixture (v/v) of the two. The basic blends were mixed with 0, 10, and 20% sphagnum peat moss (v/v) and 0, 10, and 20% natural zeolites (v/v) and placed in 15-cm-diameter pots in a greenhouse. Bermudagrass plugs were planted in each pot. The addition of sphagnum peat moss to the basic ExSh/QS blend increased bermudagrass growth and improved plant response to added fertilizer. Zeolites had no significant effect on plant growth in the absence of sphagnum peat moss. Growing mediums that contained 10 to 20% sphagnum peat moss and 10 to 20% zeolites consistently produced more bermudagrass biomass than the unamended ExSh/QS mixture. Changing the ratio of small- to large-diameter ExSh in the basic medium did not affect bermudagrass yield. Very low amounts of Cd, Cu, Pb, and Zn were recovered in leachate after the addition of 10 mg metal per pot, suggesting that most heavy metals (>99%) were retained in the growing mediums. Zeolites reduced the amount of Cd and Pb in leachate water, but not Cu or Zn.

Sloan JJ; Hegemann MA; George SA

2008-11-01

280

Dual-function growth medium and structural soil for use as porous pavement.  

Science.gov (United States)

Permeable grass-covered surfaces can reduce the quantity of storm water runoff and filter out potentially harmful chemicals. The objective of this study was to develop permeable structural soils that sustained healthy turf growth and filtered heavy metals from contaminated pavement runoff. The basic soil medium was a 50:50 mixture (v/v) of expanded shale (ExSh) and quartz sand (QS). The ExSh component consisted of (i) large-diameter particles (3-6 mm), (ii) small-diameter particles (1-3 mm), or (iii) a 50:50 mixture (v/v) of the two. The basic blends were mixed with 0, 10, and 20% sphagnum peat moss (v/v) and 0, 10, and 20% natural zeolites (v/v) and placed in 15-cm-diameter pots in a greenhouse. Bermudagrass plugs were planted in each pot. The addition of sphagnum peat moss to the basic ExSh/QS blend increased bermudagrass growth and improved plant response to added fertilizer. Zeolites had no significant effect on plant growth in the absence of sphagnum peat moss. Growing mediums that contained 10 to 20% sphagnum peat moss and 10 to 20% zeolites consistently produced more bermudagrass biomass than the unamended ExSh/QS mixture. Changing the ratio of small- to large-diameter ExSh in the basic medium did not affect bermudagrass yield. Very low amounts of Cd, Cu, Pb, and Zn were recovered in leachate after the addition of 10 mg metal per pot, suggesting that most heavy metals (>99%) were retained in the growing mediums. Zeolites reduced the amount of Cd and Pb in leachate water, but not Cu or Zn. PMID:18948478

Sloan, John J; Hegemann, Mary Ann; George, Steve A

2008-10-23

 
 
 
 
281

A study of sound absorption by street canyon boundaries and asphalt rubber concrete pavement  

Science.gov (United States)

A sound field model, based on a classical diffusion equation, is extended to account for sound absorption in a diffusion parameter used to model sound energy in a narrow street canyon. The model accounts for a single sound absorption coefficient, separate accommodation coefficients and a combination of separate absorption and accommodation coefficients from parallel canyon walls. The new expressions are compared to the original formula through numerical simulations to reveal the effect of absorption on sound diffusion. The newly established analytical formulae demonstrate satisfactory agreement with their predecessor under perfect reflection. As well, the influence of the extended diffusion parameter on normalized sound pressure levels in a narrow street canyon is in agreement with experimental data. The diffusion parameters are used to model sound energy density in a street canyon as a function of the sound absorption coefficient of the street canyon walls. The acoustic and material properties of conventional and asphalt rubber concrete (ARC) pavement are also studied to assess how the crumb rubber content influences sound absorption in street canyons. The porosity and absolute permeability of compacted specimens of asphalt rubber concrete are measured and compared to their normal and random incidence sound absorption coefficients as a function of crumb rubber content in the modified binder. Nonlinear trends are found between the sound absorption coefficients, porosity and absolute permeability of the compacted specimens and the percentage of crumb rubber in the modified binders. The cross-sectional areas of the air voids on the surfaces of the compacted specimens are measured using digital image processing techniques and a linear relationship is obtained between the average void area and crumb rubber content. The measured material properties are used to construct an empirical formula relating the average porosity, normal incidence noise reduction coefficients and percentage of crumb rubber in the modified binder of the compacted specimens.

Drysdale, Graeme Robert

282

Psychological distress among women with breast problems.  

Science.gov (United States)

Visiting a physician for evaluation of a breast problem which could be cancer is often assumed to be a highly stressful experience. This study evaluates the degree of emotional distress in women about to undergo examination for signs or symptoms of breast disease. Three hundred twenty-two women who attended the Breast Problem Clinic of the Wisconsin Clinical Cancer Center were studied. Each patient completed standard self-administered psychologic tests to evaluate mood disturbance (Profile of Mood States [POMS]) and responsibility taken for overall health care (Health Locus of Control [HLCS]). Results of these tests were compared to control populations of normal college women and female psychiatric outpatients. The women seen in the Breast Problem Clinic were significantly less distressed on POMS subscales which measure depression, anger, fatigue, and confusion than both psychiatric outpatients and normal college women (P less than 0.001). A second group of 17 women who were seen in the hospital 24 to 48 hours before definitive breast cancer surgery were also studied. Women evaluated as inpatients before breast cancer surgery were more distressed than the women attending the outpatient clinic on most POMS subscales, but were not clearly different from normal college women. No differences between the groups were seen for the HLCS. These data indicate that emotional distress among women attending a breast problem clinic is not extraordinary, but that emotional distress heightens when the diagnosis of breast cancer is known. PMID:3943021

Romsaas, E P; Malec, J F; Javenkoski, B R; Trump, D L; Wolberg, W H

1986-02-15

283

Psychological distress among women with breast problems.  

UK PubMed Central (United Kingdom)

Visiting a physician for evaluation of a breast problem which could be cancer is often assumed to be a highly stressful experience. This study evaluates the degree of emotional distress in women about to undergo examination for signs or symptoms of breast disease. Three hundred twenty-two women who attended the Breast Problem Clinic of the Wisconsin Clinical Cancer Center were studied. Each patient completed standard self-administered psychologic tests to evaluate mood disturbance (Profile of Mood States [POMS]) and responsibility taken for overall health care (Health Locus of Control [HLCS]). Results of these tests were compared to control populations of normal college women and female psychiatric outpatients. The women seen in the Breast Problem Clinic were significantly less distressed on POMS subscales which measure depression, anger, fatigue, and confusion than both psychiatric outpatients and normal college women (P less than 0.001). A second group of 17 women who were seen in the hospital 24 to 48 hours before definitive breast cancer surgery were also studied. Women evaluated as inpatients before breast cancer surgery were more distressed than the women attending the outpatient clinic on most POMS subscales, but were not clearly different from normal college women. No differences between the groups were seen for the HLCS. These data indicate that emotional distress among women attending a breast problem clinic is not extraordinary, but that emotional distress heightens when the diagnosis of breast cancer is known.

Romsaas EP; Malec JF; Javenkoski BR; Trump DL; Wolberg WH

1986-02-01

284

Piracetam for fetal distress in labour.  

UK PubMed Central (United Kingdom)

BACKGROUND: Piracetam is thought to promote the metabolism of brain cells when they are hypoxic. It has been used to prevent adverse effects of fetal distress. OBJECTIVES: The objective of this review was to assess the effects of piracetam for suspected fetal distress in labour on method of delivery and perinatal morbidity. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (15 February 2012). SELECTION CRITERIA: Randomised trials of piracetam compared with placebo or no treatment for suspected fetal distress in labour. DATA COLLECTION AND ANALYSIS: Both review authors assessed eligibility and trial quality. MAIN RESULTS: One study of 96 women was included. Piracetam compared with placebo was associated with a trend to reduced need for caesarean section (risk ratio 0.57, 95% confidence interval 0.32 to 1.03). There were no statistically significant differences between the piracetam and placebo group for neonatal morbidity (measured by neonatal respiratory distress) or Apgar score. AUTHORS' CONCLUSIONS: There is not enough evidence to evaluate the use of piracetam for fetal distress in labour.

Hofmeyr GJ; Kulier R

2012-01-01

285

Psychological distress among patients with epilepsy.  

UK PubMed Central (United Kingdom)

BACKGROUND: Epilepsy is a disorder of the brain characterized by recurrent seizures which are physical reactions to sudden, usually brief, too much electrical discharges in a group of brain cells. Psychological distress often accompanies epilepsy. It badly affects the disease and the treatment outcome. Whereas, familial social support is a positive factor. The objective of the present study was to see the difference of Psychological distress among the patients of Epilepsy; the comparisons on the variables of the study were made between gender, age, marital status, education, socio-economic status and type of Epilepsy. MATERIALS AND METHODS: Sample comprised of 50 patients with epilepsy. These participants were divided into three subgroups according to their ages that are children, adolescence and adults. Patients were taken from hospitals Islamabad and Muzaffarabad (AJK). RESULTS: The result showed that psychological distress is higher among male patients with generalized epilepsy and among those who are un-married, un-educated, having low socioeconomic status and lower familial social support. CONCLUSION: It can be concluded that psychological distress is common co morbidity in patients with epilepsy. During treatment, Counseling to the patients and the family can better help in coping with distress during their illness.

Khalid A; Aslam N

2011-01-01

286

Modeling Temperature and Resilient Modulus of Asphalt Pavements for Tropic Zones of Iran  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In the present study, a temperature model and a resilient modulus model of asphalt pavements are developed for tropical zones of Iran. Through the investigation of asphalt mixtures reactions to temperature increase, a mathematical model is developed. This model makes the prediction of asphalt co...

S.A. Tabatabaie; H. Ziari; M. Khalili

287

Assessment of the performance of warm mix asphalts in road pavements  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Several processes and products are available to produce warm mix asphalt (WMA). These may reduce the mixing and compaction temperatures in relation to hot mix asphalt (HMA), ensuring the necessary performance in the pavement. Lower plant mixing temperatures mean reduction in fuel consumption and low...

Silva, Hugo Manuel Ribeiro Dias da; Oliveira, Joel; Ferreira, C. I. G.; Pereira, Paulo A. A.

288

Structural Evaluation of Porous Pavement Test Sections at Walden Pond State Reservation, Concord, Massachusetts.  

Science.gov (United States)

This report presents the results of repeated load tests upon various porous pavement test sections constructed in an overflow parking lot at Walden Pond State Reservation in Concord, Massachusetts. From the fall of 1977 to the spring of 1979, the seasonal...

P. C. Marzbanian R. A. Eaton

1980-01-01

289

Monitoring of the permeable pavement demonstration site at Edison Environmental Center  

Science.gov (United States)

The EPAâ??s Urban Watershed Management Branch has installed an instrumented, working full-scale 110-space pervious pavement parking lot and has been monitoring several environmental stressors and runoff. This parking lot demonstration site has allowed the investigation of differenc...

290

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

Science.gov (United States)

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

291

Permeable Pavement Research at NRMRLâ??s Urban Watershed Research Facility  

Science.gov (United States)

The results of a bench-scale study of a porous pavement parking lot. Flow rates and total suspended solids (TSS) removal are discussed for systems with a geotextile filter fabric liner in place and those without. The systems with a liner have ~20% better TSS removal performance a...

292

Soil remediation by surface heating and vacuum extraction  

Energy Technology Data Exchange (ETDEWEB)

A novel in-situ, thermal-vacuum method has been developed to remove contaminants from near-surface soils and pavements. Heat is supplied to the soil by downward conduction from a surface heater. Vaporized products are collected under an impermeable sheet into a vacuum system for further treatment or disposal.

Stegemeir, G.L. [GLS Engineering Inc., Houston, TX (United States); Vinegar, H.J. [Shell Development Co., Houston, TX (United States)

1995-12-01

293

A TECHNIQUE OF ESTIMATION OF TECHNICAL CONDITION OF RIGID AIRFIELD PAVEMENTS IN THE CONTEXT OF RISK THEORY  

Directory of Open Access Journals (Sweden)

Full Text Available Problem statement. To provide for safe takeoff and landing of modern aviation complexes, specialattention is given to technical condition of artificial pavements of runways which can be serviceableor faulty, efficient or limiting. Available standard methods of an expeditious estimation of an operational-technical condition of airfield pavements are based on general principles of defect graduationand of definition of integrated total generalized indicator of pavement condition and often yield theresults contradicting each other, which complicate making decision in relation to operation.Results and conclusions. The classification of linear constructions of airfields by responsibilitylevel is proposed. Theoretical basics and practical recommendations on estimation of a technicalcondition of rigid airfield pavements by permissible level of are formulated with respect to level ofrisk with the use of principals of reliability theory and of risk theory. The recommendations proposedrest on new principles of technical regulation established by Federal Law N 184-FZ “Ontechnical regulation”.

A. N. Popov; I. G. Shashkov; A. V. Kozlov

2012-01-01

294

Study on the Application of a Management System for Pavement Based on iPad Terminal with GIS  

Directory of Open Access Journals (Sweden)

Full Text Available With the rapid development in the construction of highway recently, the traffic volume is increasing rapidly which cause the critical problem of the pavement maintenance and management. Current systems couldnt meet the need of it and also have an impact on the development and operation of our highway. In this study, a management and service platform for pavement, based on an iPad terminal with GIS, is designed. On the basis of the existing pavement and lots of researches and experiments, it also relies on the GIS technology which is powerful in spatial orientation, graphics processing and displays, iPad terminal with strong processing and remote infinite transmission. Then it will solve some problems in our maintenance of pavement to some extent.

Yan Jiao; Zhou Bowen; Hu Siranc

2012-01-01

295

Moral distress among healthcare professionals at a health system.  

UK PubMed Central (United Kingdom)

Moral distress is increasingly recognized as a problem affecting healthcare professionals. If not addressed, it may create job dissatisfaction, withdrawal from the moral dimensions of patient care, or even leaving the profession. Using the 21-Moral Distress Scale-Revised to assess moral distress, 323 surveys were received from 5 healthcare disciplines. The overall results showed that all disciplines experienced moderate to high actual moral distress, related to similar and/or different patient care situations.

Allen R; Judkins-Cohn T; Develasco R; Forges E; Lee R; Clark L; Procunier M

2013-07-01

296

[Acute respiratory distress revealing severe pulmonary leptospirosis  

UK PubMed Central (United Kingdom)

We return a clinical case of leptospirose revelated by a complicated febrile harp pneumopathie of a sharp respiratory distress syndrome having required a transfer in resuscitation. The goal of our article is to recall that it is necessary to think systematically about a pulmonary shape of leptospirose facing an atypical pneumopahie.

Sekkach Y; Qaçif H; Jira M; El Qatni M; El omri N; Ghafir D

2007-01-01

297

[Acute respiratory distress revealing severe pulmonary leptospirosis].  

Science.gov (United States)

We return a clinical case of leptospirose revelated by a complicated febrile harp pneumopathie of a sharp respiratory distress syndrome having required a transfer in resuscitation. The goal of our article is to recall that it is necessary to think systematically about a pulmonary shape of leptospirose facing an atypical pneumopahie. PMID:17141924

Sekkach, Y; Qaçif, H; Jira, M; El Qatni, M; El omri, N; Ghafir, D

2006-10-06

298

Spiritual distress: integrative review of literature  

Directory of Open Access Journals (Sweden)

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

Erika Cássia Lopes Chaves; Emília Campos de Carvalho; Sueli Leiko Takamatsu Goyatá; Cristina Maria Galvão

2008-01-01

299

Discrimination Distress among Chinese American Adolescents  

Science.gov (United States)

This paper addresses contradictions between common perceptions of Asian Americans as a "model minority" and growing evidence of discrimination and its negative psychological implications for this group. The current study examined Chinese American early adolescents' distress from experiences of discrimination, its relationship with mental health…

Grossman, Jennifer M.; Liang, Belle

2008-01-01

300

Pictures of a client's silent distress.  

UK PubMed Central (United Kingdom)

A trust-based nurse-patient relationship and open communication can help nurses alleviate clients' intrapersonal and interpersonal distress. However, the client's silence about unspoken needs can present an obstacle to successful holistic care. This article describes how pictures, both mental and printed, can be used by nurses to open pathways of healing communication and holistic nursing care.

Felicilda RF

2011-01-01

 
 
 
 
301

Happiness and Death Distress: Two Separate Factors  

Science.gov (United States)

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

Abdel-Khalek, Ahmed M.

2005-01-01

302

Maternal oxygen administration for fetal distress.  

UK PubMed Central (United Kingdom)

BACKGROUND: Maternal oxygen administration has been used in an attempt to lessen fetal distress by increasing the available oxygen from the mother. This has been used for suspected fetal distress during labour, and prophylactically during the second stage of labour on the assumption that the second stage is a time of high risk for fetal distress. OBJECTIVES: The objective of this review was to assess the effects of maternal oxygenation for fetal distress during labour and to assess the effects of prophylactic oxygen therapy during the second stage of labour on perinatal outcome. SEARCH METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (22 October 2012) and searched reference lists of retrieved studies. SELECTION CRITERIA: Randomized trials comparing maternal oxygen administration for fetal distress during labour and prophylactic oxygen administration during the second stage of labour with a control group (dummy or no oxygen therapy). DATA COLLECTION AND ANALYSIS: Both review authors assessed eligibility and trial quality. Data were extracted, checked and entered into Review Manager software. For dichotomous data, we calculated relative risks (RR) and 95% confidence intervals (CI). For continuous data, we calculated weighted mean differences and 95% CI. MAIN RESULTS: We located no trials addressing maternal oxygen therapy for fetal distress. We included two trials which addressed prophylactic oxygen administration during labour. Abnormal cord blood pH values (less than 7.2) were recorded significantly more frequently in the oxygenation group than the control group (RR 3.51, 95% CI 1.34 to 9.19). There were no other statistically significant differences between the groups. There were conflicting conclusions on the effect of the duration of oxygen administration on umbilical artery pH values between the two trials. AUTHORS' CONCLUSIONS: Implications for practice There is not enough evidence to support the use of prophylactic oxygen therapy for women in labour, nor to evaluate its effectiveness for fetal distress.Implications for research In view of the widespread use of oxygen administration during labour and the possibility that it may be ineffective or harmful, there is an urgent need for randomized trials to assess its effects.

Fawole B; Hofmeyr GJ

2012-01-01

303

Distress in Patients With Acute Leukemia: A Concept Analysis.  

UK PubMed Central (United Kingdom)

BACKGROUND:: Patients with acute leukemia (AL) require immediate and aggressive inpatient treatment that results in many weeks to months of hospitalization. Thus, it is not surprising that distress has been found in as many as 45.5% of patients. Although distress is a regularly reported outcome measure in clinical research, currently, there is a lack of a clear, consistent, and universal definition of this concept. OBJECTIVE:: The purposes of this article were to examine the current state of the science surrounding the concept of distress and to propose a model of distress for patients with AL. INTERVENTIONS/METHODS:: The Walker and Avant framework was used to guide the analysis of the concept of distress in patients with AL. The findings from this analysis were then used to generate a model guided by the current science. RESULTS:: Distress in AL is generally accepted as multidimensional, quantifiable, subjective, and temporal. Antecedents to distress include demographics, intrinsic factors, social support, disease progression, treatment, and communication. Consequences to distress include decreased quality of life, patient outcomes, as well as the severity of physical and psychological symptoms. CONCLUSIONS:: Distress is an outcome measure that is frequently assessed and reported within the literature. The operationalization of distress varies by investigator, limiting its generalizability. IMPLICATIONS FOR PRACTICE:: The proposed conceptual model may be used to guide further research on distress in patients with AL at high risk for negative outcomes. Improved understanding of patient distress may guide interventions aimed at managing the psychosocial needs for patients receiving treatment for AL.

Albrecht TA; Rosenzweig M

2013-04-01

304

Effects of reclaimed asphalt pavement on indirect tensile strength test of foamed asphalt mix tested in dry condition  

Science.gov (United States)

Indirect tensile strength (ITS) test was conducted to analyse strength of the foamed asphalt mixes incorporating reclaimed asphalt pavement. Samples were tested for ITS after cured in the oven at 40°C for 72 hours. This testing condition known as dry condition or unconditioned. Laboratory results show that reclaimed asphalt pavement (RAP) contents insignificantly affect the ITS results. ITS results significantly affected by foamed bitumen contents.

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

2013-06-01

305

The spiritual distress assessment tool: an instrument to assess spiritual distress in hospitalised elderly persons  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Although spirituality is usually considered a positive resource for coping with illness, spiritual distress may have a negative influence on health outcomes. Tools are needed to identify spiritual distress in clinical practice and subsequently address identified needs. This study describes the first steps in the development of a clinically acceptable instrument to assess spiritual distress in hospitalized elderly patients. Methods A three-step process was used to develop the Spiritual Distress Assessment Tool (SDAT): 1) Conceptualisation by a multidisciplinary group of a model (Spiritual Needs Model) to define the different dimensions characterizing a patient's spirituality and their corresponding needs; 2) Operationalisation of the Spiritual Needs Model within geriatric hospital care leading to a set of questions (SDAT) investigating needs related to each of the defined dimensions; 3) Qualitative assessment of the instrument's acceptability and face validity in hospital chaplains. Results Four dimensions of spirituality (Meaning, Transcendence, Values, and Psychosocial Identity) and their corresponding needs were defined. A formalised assessment procedure to both identify and subsequently score unmet spiritual needs and spiritual distress was developed. Face validity and acceptability in clinical practice were confirmed by chaplains involved in the focus groups. Conclusions The SDAT appears to be a clinically acceptable instrument to assess spiritual distress in elderly hospitalised persons. Studies are ongoing to investigate the psychometric properties of the instrument and to assess its potential to serve as a basis for integrating the spiritual dimension in the patient's plan of care.

Monod Stefanie M; Rochat Etienne; Büla Christophe J; Jobin Guy; Martin Estelle; Spencer Brenda

2010-01-01

306

The spiritual distress assessment tool: an instrument to assess spiritual distress in hospitalised elderly persons.  

UK PubMed Central (United Kingdom)

BACKGROUND: Although spirituality is usually considered a positive resource for coping with illness, spiritual distress may have a negative influence on health outcomes. Tools are needed to identify spiritual distress in clinical practice and subsequently address identified needs. This study describes the first steps in the development of a clinically acceptable instrument to assess spiritual distress in hospitalized elderly patients. METHODS: A three-step process was used to develop the Spiritual Distress Assessment Tool (SDAT): 1) Conceptualisation by a multidisciplinary group of a model (Spiritual Needs Model) to define the different dimensions characterizing a patient's spirituality and their corresponding needs; 2) Operationalisation of the Spiritual Needs Model within geriatric hospital care leading to a set of questions (SDAT) investigating needs related to each of the defined dimensions; 3) Qualitative assessment of the instrument's acceptability and face validity in hospital chaplains. RESULTS: Four dimensions of spirituality (Meaning, Transcendence, Values, and Psychosocial Identity) and their corresponding needs were defined. A formalised assessment procedure to both identify and subsequently score unmet spiritual needs and spiritual distress was developed. Face validity and acceptability in clinical practice were confirmed by chaplains involved in the focus groups. CONCLUSIONS: The SDAT appears to be a clinically acceptable instrument to assess spiritual distress in elderly hospitalised persons. Studies are ongoing to investigate the psychometric properties of the instrument and to assess its potential to serve as a basis for integrating the spiritual dimension in the patient's plan of care.

Monod SM; Rochat E; Büla CJ; Jobin G; Martin E; Spencer B

2010-01-01

307

Moral distress in nursing: contributing factors, outcomes and interventions.  

UK PubMed Central (United Kingdom)

Moral distress has been widely reviewed across many care contexts and among a range of disciplines. Interest in this area has produced a plethora of studies, commentary and critique. An overview of the literature around moral distress reveals a commonality about factors contributing to moral distress, the attendant outcomes of this distress and a core set of interventions recommended to address these. Interventions at both personal and organizational levels have been proposed. The relevance of this overview resides in the implications moral distress has on the nurse and the nursing workforce: particularly in regard to quality of care, diminished workplace satisfaction and physical health of staff and increased problems with staff retention.

Burston AS; Tuckett AG

2013-05-01

308

Psychological distress among women with newly diagnosed breast cancer  

DEFF Research Database (Denmark)

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

Mertz, Birgitte; Bistrup, Pernille Envold

2012-01-01

309

Young children sympathize less in response to unjustified emotional distress.  

UK PubMed Central (United Kingdom)

Three-year-old children saw an adult displaying the exact same distress in 3 different conditions: (a) the adult's distress was appropriate to a genuine harm, (b) the adult's distress was an overreaction to a minor inconvenience, and (c) there was no apparent cause for the adult's distress. Children who witnessed the adult being appropriately upset showed concern for him, intervened on his behalf, and checked on him when he later expressed distress out of their view. Children who did not know the cause for the adult's distress responded similarly. In contrast, children who witnessed the adult overreacting to an inconvenience showed lower rates of intervening and checking. The degree of children's concern across conditions was correlated with the latency of their helping behavior toward the adult later. These results suggest that from an early age, young children's sympathy and prosocial behavior are not automatic responses to emotional displays but, rather, involve taking into account whether the displayed distress is justified.

Hepach R; Vaish A; Tomasello M

2013-06-01

310

A mechanistic structural design procedure for surface mine haul roads  

Energy Technology Data Exchange (ETDEWEB)

The structural design of a pavement relates to the ability of the road to carry the imposed loads without the need for excessive maintenance or premature rehabilitation. The need to develop a practical structural design method for mine haul roads was identified. The aim of the paper is to develop a mechanistic structural design procedure for mine haul roads. The current state of mine haul road structural design was assessed through the analysis and quantification of existing pavement structural performance. These pavements were then analyzed mechanistically and through a comparative analysis of the results, the associated limiting design criteria and optimal mechanistic design were deduced. Finally, the benefits of the proposed mechanistic design method were verified by comparison with existing haul road design in the South African coal surface mines. 20 refs., 8 figs., 4 tabs.

Thompson, R.J.; Visser, A.T. [University of Pretoria, Pretoria (South Africa). Dept. of Mining Engineering

1997-12-01

311

Further developments in self-fertilising geotextiles for use in pervious pavements.  

UK PubMed Central (United Kingdom)

Geotextiles incorporating inorganic nutrients (particularly phosphorous) to enhance the growth of oil degrading microoganisms when geotextiles are used in pervious pavement applications have been shown to be effective in the past. However the cost and manufacturing difficulties have been a barrier to their use. A polypropylene random mat geotextile incorporating an alternative polymer additive as a source of phosphorus has been investigated as a potential self-fertilising geotextile. Experiments are reported which investigate nutrient leach rates, biofilm formation and biodegradation activity.

Newman AP; Nnadi EO; Duckers LJ; Cobley AJ

2011-01-01

312

[Acute adult respiratory distress syndrome in leptospirosis  

UK PubMed Central (United Kingdom)

The respiratory manifestations of leptospirosis are usually benign. A case is reported of leptospirosis with serious pulmonary affection. Pulmonary involvement in leptospirosis is infrequently predominant and usually without bearing on prognosis. Clinical and roentgenological features are reviewed. Severe forms with massive hemoptysis or acute respiratory failure occur occasionally. The clinical symptoms, the radiological manifestations and haemodynamic investigation were suggestive of an acute respiratory distress by non haemodynamic pulmonary oedema. In accordance with other authors, one could be justified in including this acute respiratory failure as part of the adult respiratory distress syndrome. Since leptospirosis has extremely diverse clinical features, physicians should have this diagnosis in mind in many circumstances and should request the appropriate examinations at the right moment. Carefully performed microbiological techniques may reduce the problems encountered in isolating leptospires. Serological tests requested after the 12th day of the disease and repeated several times should improve the diagnosis confirmation. The potential severity of certain forms justifies curative antibiotic therapy.

Hidou M

1991-01-01

313

The Global Maritime Distress and Safety System  

Science.gov (United States)

The Global Maritime Distress and Safety System (GMDSS) is discussed with respect to its initial planning, the communication network, and other details, including the fully automated Maritime Safety Information service and the implementation of the whole system. GMDSS is the result of international cooperation over a period of about 10 years and provides the maritime community with an integrated distress and safety communication system which significantly enhances the safety of life and property in the harsh environment of the sea. Probably the most essential element of the GMDSS is the provision of an adequate communication network which will permit ships in need of assistance to notify responsible authorities, discuss the help they need, and allow the search and rescue activities to be coordinated by the most appropriate center.

Kent, Peter E.

1990-08-01

314

Corticosteroids in acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

Full Text Available Improving the course and outcome of patients with acute respiratory distress syndrome presents a challenge. By understanding the immune status of a patient, physicians can consider manipulating proinflammatory systems more rationally. In this context, corticosteroids could be a therapeutic tool in the armamentarium against acute respiratory distress syndrome. Corticosteroid therapy has been studied in three situations: prevention in high-risk patients, early treatment with high-dose, short-course therapy, and prolonged therapy in unresolving cases. There are differences between the corticosteroid trials of the past and recent trials: today, treatment starts 2-10 days after disease onset in patients that failed to improve; in the past, the corticosteroid doses employed were 5-140 times higher than those used now. Additionally, in the past treatment consisted of administering one to four doses every 6 h (methylprednisolone, 30 mg/kg) versus prolonging treatment as long as necessary in the new trials (2 mg kg-1 day-1 every 6 h). The variable response to corticosteroid treatment could be attributed to the heterogeneous biochemical and molecular mechanisms activated in response to different initial insults. Numerous factors need to be taken into account when corticosteroids are used to treat acute respiratory distress syndrome: the specificity of inhibition, the duration and degree of inhibition, and the timing of inhibition. The major continuing problem is when to administer corticosteroids and how to monitor their use. The inflammatory mechanisms are continuous and cyclic, sometimes causing deterioration or improvement of lung function. This article reviews the mechanisms of action of corticosteroids and the results of experimental and clinical studies regarding the use of corticosteroids in acute respiratory distress syndrome.

A.B.S. Fernandes; W.A. Zin; P.R.M. Rocco

2005-01-01

315

Acute respiratory distress caused by massive thymolipoma.  

Science.gov (United States)

The authors present the case of a 40-year-old female with a massive anterior mediastinal tumor who presented with acute respiratory distress. She required emergent intubation and ventilatory support for respiratory compromise caused by lung compression. Preoperative computed tomographic scan results suggested a mediastinal lipomatous mass. Resection of the tumor resulted in immediate improvement in her pulmonary status. Because thymolipomas can attain enormous dimensions and compress adjacent structures, they should be resected at the time of diagnosis. PMID:15586609

Halkos, Michael E; Symbas, John D; Symbas, Panagiotis N

2004-11-01

316

Acute respiratory distress caused by massive thymolipoma.  

UK PubMed Central (United Kingdom)

The authors present the case of a 40-year-old female with a massive anterior mediastinal tumor who presented with acute respiratory distress. She required emergent intubation and ventilatory support for respiratory compromise caused by lung compression. Preoperative computed tomographic scan results suggested a mediastinal lipomatous mass. Resection of the tumor resulted in immediate improvement in her pulmonary status. Because thymolipomas can attain enormous dimensions and compress adjacent structures, they should be resected at the time of diagnosis.

Halkos ME; Symbas JD; Symbas PN

2004-11-01

317

A Comparative Field Study of Permastripe(Trademark) Polymer Concrete and Waterborne Airfield Pavement Markings  

Canada Institute for Scientific and Technical Information (Canada)

The study reported herein compared polymer concrete pavement markings (Permastripe) to Federal specification waterborne airfield marking paint for field durability and retroreflectivity. The markings were placed at Tyndall Air Force Base (AFB) (hot, wet climate) and Mountain Home AFB (cold, snowy climate). American Association State Highway and Transportation Officials Type I, Type III, and a Type I/Type III retroreflectivity bead combinations were included at Tyndall AFB. Additionally, Adsil, a novel clear coating, was used at Tyndall AFB to evaluate the effects on retroreflectivity and durability of Permastripe and paint. This study suggests that Permastripe is more durable than standard airfield paint, may exhibit better bead retention, and holds promise as a durable pavement marking if certain technical problems can be overcome. The Permastripe studied in this work is not readily removable from asphalt pavement using water-blasting. The data clearly show that high-refractive index Type III beads result in higher retroreflectivity than Type I beads initially and over time. The Adsil clear coating applied to the markings resulted in significant reductions in retroreflectivity. The retroreflectivity data from one test clearly indicates that the retroreflectivity increases with time as the coating wears.

2007-01-01

318

Numerical simulation of a 3-D flow within a storage area hexagonal modular pavement systems  

Science.gov (United States)

This numerical study has been performed to predict the flow patterns and characteristics within a storage area Hexagonal Modular Pavement Systems. Throughout the design and planning period for future construction are increasingly integrating computational fluid dynamics (CFD) into the process. A commercially known software, FLOW-3D, is applied to numerically solve the Navier-stokes equations for solution domains which are separated into three regions with overlapping boundaries to efficiently accommodate the grid resolutions, namely the honeycomb shaped modular, gravel and combined honeycomb shaped modular with gravel fill. The filtration of the fluid within the interstices of a permeable pavement is evaluated by integrating the Reynolds Averaged Navier-Stokes equations (RANS) inside the voids rather than making use of the widespread porous media approach. In conclusion, the results from numerical simulation are generally well agreed with the existing data and flow information such as flow patterns at increased flow, discharge rate and pressure is obtained to be used for engineering design purpose. Overall, the potential for FLOW-3D to model various geometries and configurations appears great. It should be noted that CFD should not be considered a complete replacement for physical modelling; however, it can definitely be used as a supplementary tool throughout the pavement design process.

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

2013-06-01

319

[Extracorporeal membrane oxygenation by acute respiratory distress syndrome  

UK PubMed Central (United Kingdom)

After various observational studies demonstrated a benefit of extracorporeal membrane oxygenation (ECMO) in the therapy of severe acute respiratory distress syndrome (ARDS), ECMO now represents an important contribution for ARDS therapy using clinical algorithms despite a lack of positive controlled studies. In specialized centers patients with severe ARDS and imminent hypoxia despite intensive conventional therapy, are treated with ECMO using blood pumps and artificial membrane lungs (oxygenators) for extracorporeal lung assist. The development of new surface modifications, optimized oxygenators and miniaturized blood pumps should increase hemocompatibility and lead to simplified treatment as well as less complications. New oxygenators with significantly decreased blood resistance allow the clinical application of pumpless arteriovenous extracorporeal lung assist (ECLA). After these new developments indications for ECMO could be extended from use not only as ultimate ratio but to less severe ARDS to enable lung protective, less invasive mechanical ventilation.

Kopp R; Henzler D; Dembinski R; Kuhlen R

2004-02-01

320

Texture and noise features for road pavement identification and classification  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Road planners and road administrators frequently face the problem of insufficient knowledge of the correlation between the type of road surface and the resulting noise emission. The aim of this research is to establish the relationship between road surface characteristics, such as macrotexture, and ...

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

 
 
 
 
321

Avaliação do ruído através do SPBI (Statistical Pass-By Index) em diferentes pavimentos Noise evaluation using the SPBI (Statistical Pass-By Index) for different pavements  

Directory of Open Access Journals (Sweden)

Full Text Available O transporte rodoviário causa grande impacto no meio ambiente, tanto pelo grande consumo de energia quanto pela infra-estrutura física necessária a sua operação. A emissão de gases e os ruídos causados pelo tráfego causam danos irreversíveis ao meio ambiente e têm sido alvo de inúmeros estudos e pesquisas. Sabe-se que o atrito pneu/pavimento e as propriedades acústicas dos revestimentos influenciam de sobremaneira a geração e a propagação do ruído. Essa pesquisa tem como objetivo avaliar o ruído causado pelo tráfego de veículos em quatro diferentes pavimentos implantados em diferentes rodovias através do SPBI (Statistical Pass-By Index). A metodologia adotada seguiu as prescrições da norma ISO 11819-1, a qual determina que um decibelímetro seja instalado na lateral da via para medir o ruído máximo causado pela passagem de um veículo. O revestimento em CBUQ foi o pavimento cujas maiores medidas foram observadas (86,84dBA) seguido do CCP (83,28dBA), do TSD (83,26dBA) do MICRO (81,14dBA) e da CPA (81,03dBA). Os resultados indicam que a escolha adequada do revestimento pode atenuar de maneira expressiva o ruído causado pelo tráfego rodoviário.Highway transportation causes immense environmental impacts, as much by the enormous use of energy as for the physical infrastructure necessary for its operation. The gas emission and traffic noise cause irreversible damages to the environment and this has been the objective of a lot of studies and researches. It is known that the contact between tire and pavement surface and the acoustic properties of the coverings influence the noise’s generation and propagation. This research aims to evaluate the noise caused by the traffic of vehicles in four different pavements through SPBI (Statistical Pass-By Index). The methodology followed the prescriptions of the norm ISO 11819-1; the decibelimeter is installed in the road side and it records the maximum noise caused by each vehicle. HMA presents higher noise measurement (86,84dBA) followed by PCC (83,28dBA), ST (83,26dBA) MICRO (81,14dBA) and PC (81,03dBA). The results indicate that correct pavement selection can reduce, in an expressive way, the noise caused by road traffic.

Luciano Pivoto Specht; Sérgio C. Callai; Oleg A. Khatchatourian; Raquel Kohler

2009-01-01

322

Avaliação do ruído através do SPBI (Statistical Pass-By Index) em diferentes pavimentos/ Noise evaluation using the SPBI (Statistical Pass-By Index) for different pavements  

Scientific Electronic Library Online (English)

Full Text Available Abstract in portuguese O transporte rodoviário causa grande impacto no meio ambiente, tanto pelo grande consumo de energia quanto pela infra-estrutura física necessária a sua operação. A emissão de gases e os ruídos causados pelo tráfego causam danos irreversíveis ao meio ambiente e têm sido alvo de inúmeros estudos e pesquisas. Sabe-se que o atrito pneu/pavimento e as propriedades acústicas dos revestimentos influenciam de sobremaneira a geração e a propagação do ruído. Essa p (more) esquisa tem como objetivo avaliar o ruído causado pelo tráfego de veículos em quatro diferentes pavimentos implantados em diferentes rodovias através do SPBI (Statistical Pass-By Index). A metodologia adotada seguiu as prescrições da norma ISO 11819-1, a qual determina que um decibelímetro seja instalado na lateral da via para medir o ruído máximo causado pela passagem de um veículo. O revestimento em CBUQ foi o pavimento cujas maiores medidas foram observadas (86,84dBA) seguido do CCP (83,28dBA), do TSD (83,26dBA) do MICRO (81,14dBA) e da CPA (81,03dBA). Os resultados indicam que a escolha adequada do revestimento pode atenuar de maneira expressiva o ruído causado pelo tráfego rodoviário. Abstract in english Highway transportation causes immense environmental impacts, as much by the enormous use of energy as for the physical infrastructure necessary for its operation. The gas emission and traffic noise cause irreversible damages to the environment and this has been the objective of a lot of studies and researches. It is known that the contact between tire and pavement surface and the acoustic properties of the coverings influence the noise?s generation and propagation. This (more) research aims to evaluate the noise caused by the traffic of vehicles in four different pavements through SPBI (Statistical Pass-By Index). The methodology followed the prescriptions of the norm ISO 11819-1; the decibelimeter is installed in the road side and it records the maximum noise caused by each vehicle. HMA presents higher noise measurement (86,84dBA) followed by PCC (83,28dBA), ST (83,26dBA) MICRO (81,14dBA) and PC (81,03dBA). The results indicate that correct pavement selection can reduce, in an expressive way, the noise caused by road traffic.

Specht, Luciano Pivoto; Callai, Sérgio C.; Khatchatourian, Oleg A.; Kohler, Raquel

2009-12-01

323

Coal-tar-based pavement sealcoat and PAHs: implications for the environment, human health, and stormwater management.  

UK PubMed Central (United Kingdom)

Coal-tar-based sealcoat products, widely used in the central and eastern U.S. on parking lots, driveways, and even playgrounds, are typically 20-35% coal-tar pitch, a known human carcinogen that contains about 200 polycyclic aromatic hydrocarbon (PAH) compounds. Research continues to identify environmental compartments-including stormwater runoff, lake sediment, soil, house dust, and most recently, air-contaminated by PAHs from coal-tar-based sealcoat and to demonstrate potential risks to biological communities and human health. In many cases, the levels of contamination associated with sealed pavement are striking relative to levels near unsealed pavement: PAH concentrations in air over pavement with freshly applied coal-tar-based sealcoat, for example, were hundreds to thousands of times higher than those in air over unsealed pavement. Even a small amount of sealcoated pavement can be the dominant source of PAHs to sediment in stormwater-retention ponds; proper disposal of such PAH-contaminated sediment can be extremely costly. Several local governments, the District of Columbia, and the State of Washington have banned use of these products, and several national and regional hardware and home-improvement retailers have voluntarily ceased selling them.

Mahler BJ; Metre PC; Crane JL; Watts AW; Scoggins M; Williams ES

2012-03-01

324

Investigation of the Frost Resistance of Air-Entrained and Nonair-Entrained Roller-Compacted Concrete (RCC) Mixtures for Pavement Applications.  

Science.gov (United States)

Roller-compacted concrete (RCC) pavement use a paving technique in which a zero-slump portland cement concrete mixture is placed using asphalt concrete pavers and compacted with vibratory and rubber-tired rollers. A reason for using RCC pavements is its d...

S. A. Ragan D. W. Pittman W. P. Grogan

1990-01-01

325

Exploring moral distress in potential sibling stem cell donors.  

UK PubMed Central (United Kingdom)

In relation to the phenomenon of moral distress, this article presents two original perspectives. First, the literature to date reflects a focus on moral distress in an occupational context. In this article, however, the impact of moral distress on siblings is explored. Moral distress is considered in a particular context, stem cell donation, but there are clear insights and implications for wider practice, particularly in life-threatening contexts and situations where live donation enhances the potential for survival. Second, the article represents some progress in relation to creating conceptual clarity. It is suggested that in addition to external and internal moral constraints a further classification of constraint emerges, and that this is useful in teasing out the distinction between moral stress and moral distress. The insights drawn from exploring the experiences of these siblings should enhance the ability to pre-empt and ameliorate potential distress and, ultimately, reduce harm.

Begley A; Piggott S

2013-03-01

326

Factors associated with financial distress of nonprofit hospitals.  

UK PubMed Central (United Kingdom)

Financial distress can have a detrimental influence on the performance of hospitals. Hospital management needs to monitor potential financial distress effectively and know how it will respond depending on the severity of the circumstances. This study examined the multiple factors that may explain the financial distress of nonprofit hospitals during 1998 to 2001 and discussed their importance. To obtain more robust results, financial distress was assessed in 2 ways: first, financial strength index was used to incorporate 4 financial dimensions including profitability, liquidity, leverage, and physical facilities; second, cash flow (CF) was used to address the issues of accrual-based accounting in hospitals. This study finds that decrease in occupancy rate and increase in Medicaid payer mix, health maintenance organization penetration, market competition, physician supply, and percentage of the elderly are associated with increased likelihood of financial distress of urban hospitals. Increases in both Medicare and Medicaid payer mix, however, are related to higher likelihood of financial distress of rural hospitals.

Kim TH

2010-01-01

327

A Demedicalized View of Maternal Distress: Conceptualization and Instrument Development.  

UK PubMed Central (United Kingdom)

The goal of this article was to describe instrument development of a demedicalized, multidomain view of maternal distress, with psychological, relational, and situational manifestations. We developed a pilot instrument derived from our previous grounded theory conceptualization of maternal distress and administered it to a purposive sample of 100 low-income single mothers. Analyses testing the relationship between maternal distress and depressive symptoms, guilt, child rearing stress, and community needs variables suggested that the maternal distress inventory had convergent, discriminant, and concurrent validity. Not only was maternal distress distinct from depressive symptomology and generalized child rearing stress, it appeared to be more meaningfully associated with "real world" outcomes of interest to psychological service providers than purely psychological measures of the distress. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Arditti JA; Grzywacz JG; Gallimore SW

2012-09-01

328

Financial Distress Prediction in Emerging Market: Empirical Evidences from Iran  

Directory of Open Access Journals (Sweden)

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

Mahdi Salehi; Bizhan Abedini

2009-01-01

329

Assessment of Distress Associated to Psychopathology in Children and Adolescents  

Directory of Open Access Journals (Sweden)

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

Lourdes Ezpeleta; Wendy Reich; Roser Granero

2009-01-01

330

Association of gastrointestinal distress in ultramarathoners with race diet.  

UK PubMed Central (United Kingdom)

CONTEXT: Gastrointestinal (GI) distress is common during ultrarunning. PURPOSE: To determine if race diet is related to GI distress in a 161-km ultramarathon. METHODS: Fifteen (10 male, 5 female) consenting runners in the Javelina Jundred (6.5 loops on a desert trail) participated. Body mass was measured immediately prerace and after each loop. Runners reported if they had nausea, vomiting, abdominal cramps, and/or diarrhea after each loop. Subjects were interviewed after each loop to record food, fluid, and electrolyte consumption. Race diets were analyzed using Nutritionist Pro. RESULTS: Nine (8 male, 1 female) of 15 runners experienced GI distress including nausea (89%), abdominal cramps (44%), diarrhea (44%), and vomiting (22%). Fluid consumption rate was higher (p = .001) in runners without GI distress (10.9 ± 3.2 ml · kg-1 · hr-1) than in those with GI distress (5.9 ± 1.6 ml · kg-1 · hr-1). Runners without GI distress consumed a higher percentage fat (p = .03) than runners with GI distress (16.5 ± 2.6 vs. 11.1 ± 5.0). In addition, fat intake rate was higher (p = .01) in runners without GI distress (0.06 ± 0.03 g · kg-1 · hr-1) than in runners with GI distress (0.03 ± 0.01 g · kg-1 ·hr-1). Lower fluid and fat intake rates were evident in those developing GI distress before the onset of symptoms. CONCLUSIONS: A race diet with higher percentage fat and higher intake rates of fat and fluid may protect ultramarathoners from GI distress. However, these associations do not indicate cause and effect, and factors other than race diet may have contributed to GI distress.

Stuempfle KJ; Hoffman MD; Hew-Butler T

2013-04-01

331

Confronting moral distress in Nursing: recognizing nurses as moral agents.  

UK PubMed Central (United Kingdom)

The concept of moral distress has brought forth a substantively different way of understanding some of the difficulties confronted by nurses in their practice. This concept highlights that nurses' distress can be an indication of nurses' conscientious moral engagement with their professional practice that has confronted practices or an environment that impedes them from acting according to their own ethical standards. Moral distress can be an indicator of problems in nurses' practice environments. This concept is described and related to moral agency in nursing practice. Selected research on moral distress is reviewed, followed by a discussion of recommendations for addressing this problem.

Carnevale FA

2013-09-01

332

Moral distress and professional freedom of speech among doctors.  

UK PubMed Central (United Kingdom)

BACKGROUND: Previous studies indicate that Norwegian doctors experience distress in their encounter with differing and partly contradictory ideals, such as the obligation to criticise unethical and inappropriate practices. The objective of this study was to investigate the perception of moral distress and professional freedom of speech among Norwegian doctors as of today, as well as identify changes that have occurred since the previous study undertaken in 2004. MATERIAL AND METHODS: A total of 1,522 economically active doctors received a questionnaire listing various statements describing the perception of moral distress and professional freedom of speech. The responses were compared to responses to the 2004 study. RESULTS: Altogether 67% of the doctors responded to the questionnaire. The proportion who reported «fairly strong» or «strong» moral distress varied from 24% to 70% among the different statements. On the whole, the «rank and file» hospital doctors reported the highest degree of moral distress. Nevertheless, a decrease in the scores for moral distress could be observed from 2004 to 2010. During the same period, the perception of professional freedom of speech increased slightly. INTERPRETATION: A reduced level of distress associated with ethical conflicts in working life may be due to improved methods for handling distressing situations, or because the consequences of the health services reorganisations are perceived as less threatening now than in 2004, immediately after the introduction of the hospital reform. However, the perceived lower distress level may also be due to professional and ethical resignation. These findings should be followed up by a qualitative study.

Førde R; Aasland OG

2013-06-01

333

Breakup Distress and Loss of Intimacy in University Students  

Directory of Open Access Journals (Sweden)

Full Text Available Breakup distress and reasons for breakup including affiliation, intimacy, sexuality and autonomy reasons were stud-ied in 119 university students who had experienced a recent breakup of a romantic relationship. The sample was di-vided into high and low breakup distress groups based on a median score on the Breakup Distress Scale. The groups were then compared on their responses on the Breakup Reasons Scale. Only the intimacy subscale differentiated the high versus low breakup distress groups. These data highlight the importance of intimacy for romantic relationships and the loss of intimacy as a reason for breakups.

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

2010-01-01

334

Development of a distress inventory for cancer: preliminary results.  

Directory of Open Access Journals (Sweden)

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

Thomas B; Mohan V; Thomas I; Pandey M

2002-01-01

335

Muted Neural Response to Distress Among Securely Attached People.  

UK PubMed Central (United Kingdom)

Neural processes that support individual differences in attachment security and affect regulation are currently unclear (Coan, 2010). Using EEG, we examined whether securely attached individuals, compared to insecure individuals, would show a muted neural response to experimentally manipulated distress. Participants completed a reaction time task that elicits error commission and the error-related negativity (ERN)-a neural signal sensitive to error-related distress-both before and after a distressing insecurity threat. Despite similar pre-threat levels, secure participants showed a stable ERN whereas insecure participants showed a post-threat increase in ERN amplitude. These results suggest a neural mechanism that allows securely attached people to regulate distress.

Nash K; Prentice M; Hirsh J; McGregor I; Inzlicht M

2013-07-01

336

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

UK PubMed Central (United Kingdom)

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

Bidstrup PE; Mertz BG; Dalton SO; Deltour I; Kroman N; Kehlet H; Rottmann N; Gärtner R; Mitchell AJ; Johansen C

2012-04-01

337

Accuracy of the Danish version of the 'distress thermometer'  

DEFF Research Database (Denmark)

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

Bidstrup, Pernille Envold; Mertz, Birgitte

2012-01-01

338

Technical note on measuring run-off dynamics from pavements using a new device: the weighable tipping bucket  

Science.gov (United States)

Due to climate change, cities need to adapt to changing rainfall and rainwater run-off dynamics. In order to develop an corresponding process based run-off model for pavements, we had to improve the measurement technique to detect run-off dynamics in an appropriate high resolution. Traditional tipping buckets (TB) have a comparable low volume resolution, capable to quantify the highest intensities in a range of expected flows. This results in varying temporal resolutions for varying flow intensities, especially in low resolutions for small flow events. Therefore, their applicability for run-off measurements and other hydrological process studies is limited, especially when the dynamics of both small and big flow events shall be measured. We improved a TB by coupling it to a balance and called it weighable tipping bucket (WTB). This paper introduces the device set up and the according data processing concept. The improved volume and temporal resolution of the WTB are demonstrated. A systematic uncertainty of TB measurements compared to WTB measurements is calculated. The impact of that increased resolution on our understanding of run-off dynamics from paved urban soils are discussed, exemplary for the run-off and the surface storage of a paved urban soil. The study was conducted on a permeably paved lysimeter situated in Berlin, Germany. Referring to the paved surface, the TB has a resolution of 0.1 mm, while the WTB has a resolution of 0.001 mm. The temporal resolution of the WTB is 3 s, the TB detects individual tippings with 0.4 s between them. Therefore, the data processing concept combines both the benefits of the balance to measure small intensities with that of the TB to measure high flow intensities. During a five months period (July to November 2009) 154 rain events were detected. Accordingly, the TB and WTB detected 47 and 121 run-off events. The total run-off was 79.6 mm measured by the WTB which was 11 % higher than detected by the TB. 95 % of that difference can be appointed to water, which evaporated from the TB. To derive a surface storage estimation, we analyzed the WTB and TB data for rain events without run-off. According to WTB data, the surface storage of the permeable pavement is 1.7 mm, while using TB data leads to an overestimation of 47 % due to low volume resolution of the TB. Combining traditional TB with modern, fast, high resolution digital balances offers the opportunity to upgrade existing TB systems in order to improve their volume detection limit and their temporal resolution, which is of great advantage for the synchronization of water balance component measurements and the investigation of hydrological processes. Furthermore, we are able to quantify the uncertainty of flow measurements gained with traditional tipping buckets.

Nehls, T.; Rim, Y. Nam; Wessolek, G.

2011-05-01

339

Technical note on measuring run-off dynamics from pavements using a new device: the weighable tipping bucket  

Directory of Open Access Journals (Sweden)

Full Text Available Due to climate change, cities need to adapt to changing rainfall and rainwater run-off dynamics. In order to develop an corresponding process based run-off model for pavements, we had to improve the measurement technique to detect run-off dynamics in an appropriate high resolution. Traditional tipping buckets (TB) have a comparable low volume resolution, capable to quantify the highest intensities in a range of expected flows. This results in varying temporal resolutions for varying flow intensities, especially in low resolutions for small flow events. Therefore, their applicability for run-off measurements and other hydrological process studies is limited, especially when the dynamics of both small and big flow events shall be described. We improved a TB by coupling it to a balance and called it weighable tipping bucket (WTB). This paper introduces the device set up and the according data processing concept. The improved volume and temporal resolution of the WTB are demonstrated. A systematic uncertainty of TB measurements compared to WTB measurements is calculated. The impact of that increased resolution on our understanding of run-off dynamics from paved urban soils are discussed, exemplary for the run-off and the surface storage of a paved urban soil. The study was conducted on a permeably paved lysimeter situated in Berlin, Germany. Referring to the paved surface, the TB has a resolution of 0.1 mm, while the WTB has a resolution of 0.001 mm. The temporal resolution of the WTB is 3 s, the TB detects individual tippings with 0.4 s between them. Therefore, the data processing concept combines both the benefits of the balance to measure small intensities with that of the TB to measure high flow intensities. During a five months period (July to November 2009) 154 rain events were detected. Accordingly, the TB and WTB detected 47 and 121 run-off events. The total run-off was 79.6 mm measured by the WTB which was 11% higher than detected by the TB. 95% of that difference can be appointed to water, which evaporated from the TB. To derive a surface storage estimation, we analyzed the WTB and TB data for rain events without run-off. According to WTB data, the surface storage of the permeable pavement is 1.7 mm, while using TB data leads to an overestimation of 47% due to low volume resolution of the TB. Combining traditional TB with modern, fast, high resolution digital balances offers the opportunity to upgrade existing TB systems in order to improve their volume detection limit and their temporal resolution, which is of great advantage for the synchronization of water balance component measurements and the investigation of hydrological processes.

T. Nehls; Y.-N. Rim; G. Wessolek

2010-01-01

340

Technical note on measuring run-off dynamics from pavements using a new device: the weighable tipping bucket  

Directory of Open Access Journals (Sweden)

Full Text Available Due to climate change, cities need to adapt to changing rainfall and rainwater run-off dynamics. In order to develop an corresponding process based run-off model for pavements, we had to improve the measurement technique to detect run-off dynamics in an appropriate high resolution. Traditional tipping buckets (TB) have a comparable low volume resolution, capable to quantify the highest intensities in a range of expected flows. This results in varying temporal resolutions for varying flow intensities, especially in low resolutions for small flow events. Therefore, their applicability for run-off measurements and other hydrological process studies is limited, especially when the dynamics of both small and big flow events shall be measured. We improved a TB by coupling it to a balance and called it weighable tipping bucket (WTB). This paper introduces the device set up and the according data processing concept. The improved volume and temporal resolution of the WTB are demonstrated. A systematic uncertainty of TB measurements compared to WTB measurements is calculated. The impact of that increased resolution on our understanding of run-off dynamics from paved urban soils are discussed, exemplary for the run-off and the surface storage of a paved urban soil. The study was conducted on a permeably paved lysimeter situated in Berlin, Germany. Referring to the paved surface, the TB has a resolution of 0.1 mm, while the WTB has a resolution of 0.001 mm. The temporal resolution of the WTB is 3 s, the TB detects individual tippings with 0.4 s between them. Therefore, the data processing concept combines both the benefits of the balance to measure small intensities with that of the TB to measure high flow intensities. During a five months period (July to November 2009) 154 rain events were detected. Accordingly, the TB and WTB detected 47 and 121 run-off events. The total run-off was 79.6 mm measured by the WTB which was 11 % higher than detected by the TB. 95 % of that difference can be appointed to water, which evaporated from the TB. To derive a surface storage estimation, we analyzed the WTB and TB data for rain events without run-off. According to WTB data, the surface storage of the permeable pavement is 1.7 mm, while using TB data leads to an overestimation of 47 % due to low volume resolution of the TB. Combining traditional TB with modern, fast, high resolution digital balances offers the opportunity to upgrade existing TB systems in order to improve their volume detection limit and their temporal resolution, which is of great advantage for the synchronization of water balance component measurements and the investigation of hydrological processes. Furthermore, we are able to quantify the uncertainty of flow measurements gained with traditional tipping buckets.

T. Nehls; Y. Nam Rim; G. Wessolek

2011-01-01

 
 
 
 
341

A Statistical Analysis to Predict Financial Distress  

Directory of Open Access Journals (Sweden)

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

Nicolas Emanuel Monti; Roberto Mariano Garcia

2010-01-01

342

Large thymolipoma causing primarily respiratory distress.  

Science.gov (United States)

Thymolipoma, is an anterior mediastinal tumor that is benign in origin. It is often asymptomatic, but can enlarge significantly prior to diagnosis. It consists of thymic and fatty tissue and is surrounded by a capsule. Less than a hundred cases have been reported worldwide. Although rare, it should be considered in the differential diagnosis of mediastinal tumors. In this paper, we report the case of a 44-year-old woman presenting with a giant thymolipoma causing symptoms of severe respiratory distress. The patient underwent surgical resection, which is the main treatment, and remains free of disease. PMID:22919867

Abi Ghanem, Moussa; Habambo, Georges; Bahous, Joudy; Chouairy, Camil; Abu Khalil, Bassam

343

Large thymolipoma causing primarily respiratory distress.  

UK PubMed Central (United Kingdom)

Thymolipoma, is an anterior mediastinal tumor that is benign in origin. It is often asymptomatic, but can enlarge significantly prior to diagnosis. It consists of thymic and fatty tissue and is surrounded by a capsule. Less than a hundred cases have been reported worldwide. Although rare, it should be considered in the differential diagnosis of mediastinal tumors. In this paper, we report the case of a 44-year-old woman presenting with a giant thymolipoma causing symptoms of severe respiratory distress. The patient underwent surgical resection, which is the main treatment, and remains free of disease.

Abi Ghanem M; Habambo G; Bahous J; Chouairy C; Abu Khalil B

2012-04-01

344

Diseño de losas de hormigón con geometría optimizada/ Design of concrete pavement with optimized slab geometry  

Scientific Electronic Library Online (English)

Full Text Available Abstract in spanish Se ha desarrollado una nueva metodología para diseñar pavimentos de hormigón, la cual reduce el espesor de losas optimizando el tamaño de estas, dada la geometría de los ejes de los camiones. El diseño considera el apoyo sobre una base granular, tratada con cemento o asfáltica. Considera que no existe adherencia entre la base, o pavimento antiguo y la losa de hormigón. El principio fundamental del método de diseño consiste en diseñar el tamaño de la losa para (more) que no más de un set de ruedas se encuentre en una determinada losa, minimizando así la tensión de tracción crítica en la superficie. Se han construido tramos de prueba a gran escala y probado bajo cargas aceleradas con espesores de hormigón de 8, 15 y 20 cm. todas con base granular y sobre capas asfálticas sin adherir. Las pruebas demostraron que una disminución en las dimensiones de la losa permite que siendo de bajo espesor, soporte una cantidad considerable de ejes equivalentes antes de comenzar a agrietarse. Las losas de hormigón sobre bases granulares con un espesor de 20 cm. no mostraron agrietamiento a pesar de haber sido ensayados a mas de 50 millones de EE. Losas de espesor de 15 cm mostraron grietas a los 12 millones de ejes equivalentes en promedio, mientras que las losas de 8 cm de espesor, resistió 75.000 ejes equivalentes antes de las primeras grietas. Además las pruebas realizadas demostraron que las losas de hormigón con fibra pueden soportar hasta 20 veces más tráfico antes de comenzar a agrietarse, así como proporcionar una vida útil más larga una vez agrietadas A partir de esto se ha desarrollado un software de diseño mecánico-empírico llamado OptiPave, que optimiza el diseño geométrico y el espesor de las losas de hormigón considerando las condiciones particulares de cada proyecto; ya sea clima, tráfico, capa, y materiales. Las tensiones críticas han sido calculadas utilizando el análisis de elementos finitos, para diferentes condiciones de cargas mecánicas y térmicas en diferentes posiciones. El agrietamiento de las losas se determina calculando la fatiga del hormigón y los modelos utilizados por la guía de diseño AASHTO del año 2007 y mediante calibración en secciones de prueba a gran escala. La nueva metodología diseña losas de hormigón que en promedio son 7 cm más delgadas para vías de alto tráfico en relación con el diseño tradicional de pavimentos AASHTO (1993). El método de diseño también es capaz de diseñar de manera eficiente pavimentos de hormigón para vías de menor volumen de tráfico que no son cubiertos con los actuales métodos de diseño de pavimento dando una alternativa a soluciones en asfalto. Abstract in english A new technology has been developed to design concrete pavements, which reduces slabs' thickness and optimizes their sizes, because of trucks axles' geometry. The design is supported by a gravel base treated with concrete or asphalt. It assumes there is no adherence between the base (existing pavement) and the concrete slab. The core principle of this design method consists of designing a slab size, so that no more than one wheel set stays on a given slab, thus minimizing (more) the critical tensile stress on the surface. Test segments have been built on a large scale and they have been tested under accelerated loads, with concrete thickness of 8, 15 and 20 cm, all of them having a gravel base and non-adhered asphaltic layers. Tests demonstrated that a reduced-size slab, of low thickness, might bear a considerable amount of equivalent axles before cracking takes place. Concrete slabs on gravel bases with 20 cm thickness did not suffer from cracking, in spite of being tested under more than 50 millions of equivalent axles. Slabs of 15 cm thickness suffered from cracking when tested under an average of 12 millions equivalent axles, while slabs of 8 cm thickness endured 75,000 equivalent axles before the first cracking took place. Besides the executed tests demonstrated that fiber concrete slabs may endure until 20 ti

Covarrubias V., Juan Pablo

2012-12-01

345

Diseño de losas de hormigón con geometría optimizada Design of concrete pavement with optimized slab geometry  

Directory of Open Access Journals (Sweden)

Full Text Available Se ha desarrollado una nueva metodología para diseñar pavimentos de hormigón, la cual reduce el espesor de losas optimizando el tamaño de estas, dada la geometría de los ejes de los camiones. El diseño considera el apoyo sobre una base granular, tratada con cemento o asfáltica. Considera que no existe adherencia entre la base, o pavimento antiguo y la losa de hormigón. El principio fundamental del método de diseño consiste en diseñar el tamaño de la losa para que no más de un set de ruedas se encuentre en una determinada losa, minimizando así la tensión de tracción crítica en la superficie. Se han construido tramos de prueba a gran escala y probado bajo cargas aceleradas con espesores de hormigón de 8, 15 y 20 cm. todas con base granular y sobre capas asfálticas sin adherir. Las pruebas demostraron que una disminución en las dimensiones de la losa permite que siendo de bajo espesor, soporte una cantidad considerable de ejes equivalentes antes de comenzar a agrietarse. Las losas de hormigón sobre bases granulares con un espesor de 20 cm. no mostraron agrietamiento a pesar de haber sido ensayados a mas de 50 millones de EE. Losas de espesor de 15 cm mostraron grietas a los 12 millones de ejes equivalentes en promedio, mientras que las losas de 8 cm de espesor, resistió 75.000 ejes equivalentes antes de las primeras grietas. Además las pruebas realizadas demostraron que las losas de hormigón con fibra pueden soportar hasta 20 veces más tráfico antes de comenzar a agrietarse, así como proporcionar una vida útil más larga una vez agrietadas A partir de esto se ha desarrollado un software de diseño mecánico-empírico llamado OptiPave, que optimiza el diseño geométrico y el espesor de las losas de hormigón considerando las condiciones particulares de cada proyecto; ya sea clima, tráfico, capa, y materiales. Las tensiones críticas han sido calculadas utilizando el análisis de elementos finitos, para diferentes condiciones de cargas mecánicas y térmicas en diferentes posiciones. El agrietamiento de las losas se determina calculando la fatiga del hormigón y los modelos utilizados por la guía de diseño AASHTO del año 2007 y mediante calibración en secciones de prueba a gran escala. La nueva metodología diseña losas de hormigón que en promedio son 7 cm más delgadas para vías de alto tráfico en relación con el diseño tradicional de pavimentos AASHTO (1993). El método de diseño también es capaz de diseñar de manera eficiente pavimentos de hormigón para vías de menor volumen de tráfico que no son cubiertos con los actuales métodos de diseño de pavimento dando una alternativa a soluciones en asfalto.A new technology has been developed to design concrete pavements, which reduces slabs' thickness and optimizes their sizes, because of trucks axles' geometry. The design is supported by a gravel base treated with concrete or asphalt. It assumes there is no adherence between the base (existing pavement) and the concrete slab. The core principle of this design method consists of designing a slab size, so that no more than one wheel set stays on a given slab, thus minimizing the critical tensile stress on the surface. Test segments have been built on a large scale and they have been tested under accelerated loads, with concrete thickness of 8, 15 and 20 cm, all of them having a gravel base and non-adhered asphaltic layers. Tests demonstrated that a reduced-size slab, of low thickness, might bear a considerable amount of equivalent axles before cracking takes place. Concrete slabs on gravel bases with 20 cm thickness did not suffer from cracking, in spite of being tested under more than 50 millions of equivalent axles. Slabs of 15 cm thickness suffered from cracking when tested under an average of 12 millions equivalent axles, while slabs of 8 cm thickness endured 75,000 equivalent axles before the first cracking took place. Besides the executed tests demonstrated that fiber concrete slabs may endure until 20 times more traffic before cracking and they are able to p

Juan Pablo Covarrubias V.

2012-01-01

346

Translating 'distress' and screening for emotional distress in multicultural cancer patients in Israel.  

UK PubMed Central (United Kingdom)

BACKGROUND: The adaptability of the distress thermometer (DT) to multicultural groups has rarely been assessed. AIMS: To assess DT adaptability to the Israeli population as a multicultural society. METHODS: Participants were 496 cancer patients. They were recruited for 3 days a week in 2009-2010 (97% response rate). Participants completed the DT, a problem list, Hospital Anxiety and Depression Scale (HADS), and the Brief Symptom Inventory (BSI-18). RESULTS: Receiver-operating characteristic (ROC) curve analyses of DT scores yielded area under the curve (AUC) of 0.63 as against HADS and of 0.78 as against BSI-18. ROC analysis revealed that the optimal cutoff score was ? 3. It yielded sensitivity and specificity of 0.74 and 0.65, as against the HADS, and 0.64 and 0.64, as against the BSI-18. The Jewish participants reported higher distress than the Arab participants, and the ROC properties were markedly higher for the Jewish subgroup alone. CONCLUSIONS: The adapted DT was moderately efficient for detecting emotional distress in cancer patients in Israel. Cultural aspects related to distress should be taken into account for administration of the DT in multicultural societies.

Cohen M; Gagin R; Cinamon T; Stein T; Moscovitz M; Kuten A

2012-05-01

347

Effectiveness of low impact development practices in two urbanized watersheds: retrofitting with rain barrel/cistern and porous pavement.  

Science.gov (United States)

The impacts of urbanization on hydrology and water quality can be minimized with the use of low impact development (LID) practices in urban areas. This study assessed the performance of rain barrel/cistern and porous pavement as retrofitting technologies in two urbanized watersheds of 70 and 40 km(2) near Indianapolis, Indiana. Six scenarios consisting of the watershed existing condition, 25% and 50% implementation of rain barrel/cistern and porous pavement, and 25% rain barrel/cistern combined with 25% porous pavement were evaluated using a proposed LID modeling framework and the Long-Term Hydrologic Impact Assessment (L-THIA)-LID model. The model was calibrated for annual runoff from 1991 to 2000, and validated from 2001 to 2010 for the two watersheds. For the calibration period, R(2) and NSE values were greater than 0.60 and 0.50 for annual runoff and streamflow. Baseflow was not calibrated in this study. During the validation period, R(2) and NSE values were greater than 0.50 for runoff and streamflow, and 0.30 for baseflow in the two watersheds. The various application levels of barrel/cistern and porous pavement resulted in 2-12% reduction in runoff and pollutant loads for the two watersheds. Baseflow loads slightly increased with increase in baseflow by more than 1%. However, reduction in runoff led to reduction in total streamflow and associated pollutant loads by 1-9% in the watersheds. The results also indicate that the application of 50% rain barrel/cistern, 50% porous pavement and 25% rain barrel/cistern combined with 25% porous pavement are good retrofitting options in these watersheds. The L-THIA-LID model can be used to inform management and decision-making for implementation of LID practices at the watershed scale. PMID:23474339

Ahiablame, Laurent M; Engel, Bernard A; Chaubey, Indrajeet

2013-03-08

348

Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material  

International Nuclear Information System (INIS)

[en] In regions where studded tyres and traction material are used during winter, e.g. the Nordic countries, northern part of USA, Canada, and Japan, mechanically generated particles from traffic are the main reason for high particle mass concentrations in busy street and road environments. In many Nordic municipalities the European environmental quality standard for inhalable particles (PM10) is exceeded due to these particles. In this study, particles from the wear of studded and studless friction tyres on two pavements and traction sanding were generated using a road simulator. The particles were characterized using particle sizers, Particle Induced X-Ray Emission Analysis and electron microscopy. Cell studies were conducted on particles sampled from the tests with studded tyres and compared with street environment, diesel exhaust and subway PM10, respectively. The results show that in the road simulator, where resuspension is minimized, studded tyres produce tens of times more particles than friction tyres. Chemical analysis of the sampled particles shows that the generated wear particles consist almost entirely of minerals from the pavement stone material, but also that Sulfur is enriched for the submicron particles and that Zink is enriched for friction tyres for all particles sizes. The chemical data can be used for source identification and apportionment in urban aerosol studies. A mode of ultra-fine particles was also present and is hypothesised to originate in the tyres. Further, traction material properties affect PM10 emission. The inflammatory potential of the particles from wear of pavements seems to depend on type of pavement and can be at least as potent as diesel exhaust particles. The results imply that there is a need and a good potential to reduce particle emission from pavement wear and winter time road and street operation by adjusting both studded tyre use as well as pavement and traction material properties

2008-04-15

349

Effectiveness of low impact development practices in two urbanized watersheds: retrofitting with rain barrel/cistern and porous pavement.  

UK PubMed Central (United Kingdom)

The impacts of urbanization on hydrology and water quality can be minimized with the use of low impact development (LID) practices in urban areas. This study assessed the performance of rain barrel/cistern and porous pavement as retrofitting technologies in two urbanized watersheds of 70 and 40 km(2) near Indianapolis, Indiana. Six scenarios consisting of the watershed existing condition, 25% and 50% implementation of rain barrel/cistern and porous pavement, and 25% rain barrel/cistern combined with 25% porous pavement were evaluated using a proposed LID modeling framework and the Long-Term Hydrologic Impact Assessment (L-THIA)-LID model. The model was calibrated for annual runoff from 1991 to 2000, and validated from 2001 to 2010 for the two watersheds. For the calibration period, R(2) and NSE values were greater than 0.60 and 0.50 for annual runoff and streamflow. Baseflow was not calibrated in this study. During the validation period, R(2) and NSE values were greater than 0.50 for runoff and streamflow, and 0.30 for baseflow in the two watersheds. The various application levels of barrel/cistern and porous pavement resulted in 2-12% reduction in runoff and pollutant loads for the two watersheds. Baseflow loads slightly increased with increase in baseflow by more than 1%. However, reduction in runoff led to reduction in total streamflow and associated pollutant loads by 1-9% in the watersheds. The results also indicate that the application of 50% rain barrel/cistern, 50% porous pavement and 25% rain barrel/cistern combined with 25% porous pavement are good retrofitting options in these watersheds. The L-THIA-LID model can be used to inform management and decision-making for implementation of LID practices at the watershed scale.

Ahiablame LM; Engel BA; Chaubey I

2013-04-01

350

Properties and toxicological effects of particles from the interaction between tyres, road pavement and winter traction material.  

Science.gov (United States)

In regions where studded tyres and traction material are used during winter, e.g. the Nordic countries, northern part of USA, Canada, and Japan, mechanically generated particles from traffic are the main reason for high particle mass concentrations in busy street and road environments. In many Nordic municipalities the European environmental quality standard for inhalable particles (PM(10)) is exceeded due to these particles. In this study, particles from the wear of studded and studless friction tyres on two pavements and traction sanding were generated using a road simulator. The particles were characterized using particle sizers, Particle Induced X-Ray Emission Analysis and electron microscopy. Cell studies were conducted on particles sampled from the tests with studded tyres and compared with street environment, diesel exhaust and subway PM(10), respectively. The results show that in the road simulator, where resuspension is minimized, studded tyres produce tens of times more particles than friction tyres. Chemical analysis of the sampled particles shows that the generated wear particles consist almost entirely of minerals from the pavement stone material, but also that Sulfur is enriched for the submicron particles and that Zink is enriched for friction tyres for all particles sizes. The chemical data can be used for source identification and apportionment in urban aerosol studies. A mode of ultra-fine particles was also present and is hypothesised to originate in the tyres. Further, traction material properties affect PM(10) emission. The inflammatory potential of the particles from wear of pavements seems to depend on type of pavement and can be at least as potent as diesel exhaust particles. The results imply that there is a need and a good potential to reduce particle emission from pavement wear and winter time road and street operation by adjusting both studded tyre use as well as pavement and traction material properties. PMID:18258284

Gustafsson, Mats; Blomqvist, Göran; Gudmundsson, Anders; Dahl, Andreas; Swietlicki, Erik; Bohgard, Mats; Lindbom, John; Ljungman, Anders

2008-02-06

351

Method of vegetation slope pavement of level fluctuation zone  

UK PubMed Central (United Kingdom)

A method for preparing plant slope protection on rising and falling limb of water surface applies scheme of sowing amphibious plant seeds as main then planting amphibious plant nursery stock as auxiliary on slope of rising and falling limb to form ecological protective plant group configured by musky and grass with water logging proof and draught enduring nature.

ZHANG YUCHANG ZHANG

352

Psychological resilience contributes to low emotional distress in cancer patients.  

UK PubMed Central (United Kingdom)

PURPOSE: Although a considerable number of cancer patients suffer from emotional distress which may have an impact on their quality of life, it still remains poorly understood which psychosocial factors contribute to individual vulnerabilities to emotional distress of cancer patients. Recently, resilience has been suggested as the capacity to cope with adversities like cancer. In this study, we investigated the relationships between resilience and emotional distress in cancer patients. METHODS: One hundred fifty-two cancer patients who were consecutively hospitalized for their scheduled treatments at the Seoul St. Mary's Hospital were enrolled and completed the Connor-Davidson Resilience Scale and Hospital Anxiety Depression Scale to measure resilience and emotional distress. The relationships between the levels of psychological resilience and emotional distress were evaluated using univariate and multivariate logistic regression analyses. RESULTS: Psychological resilience levels were negatively associated with emotional distress after controlling for relevant covariates. The highest quartile of resilience level was associated with a 90% (adjusted odds ratio [OR] = 0.10, 95% confidence interval [CI] = 0.03-0.34, P < 0.001) reduction in the risk for emotional distress compared to the lowest quartile. Among metastatic cancer patients, resilience was also found to be a significant protective factor for emotional distress (adjusted OR = 0.14, 95% CI = 0.02-0.79, P = 0.02). CONCLUSION: The present study suggests that psychological resilience may independently contribute to low emotional distress in cancer patients. The relationship between resilience and emotional distress was also significant in the subgroup of metastatic cancer patients. Psychosocial interventions to enhance resilience might provide useful approaches to overcome cancer-related emotional distress.

Min JA; Yoon S; Lee CU; Chae JH; Lee C; Song KY; Kim TS

2013-09-01

353

Hospitals in distress. Problems and solutions.  

UK PubMed Central (United Kingdom)

In the past five years the number of hospitals in financial distress has increased alarmingly. And though hospital administrators are feeling more optimistic now that their institutions will survive, they recognize the need to remain vigilant. It is important to recognize the warning signs of financial distress. Hospitals normally proceed through four stages of financial disintegration if no measures are taken to intercede: weak performance/condition, default, bankruptcy and dissolution. As the stages progress, fewer options for redress can be taken and loss of personnel and assets becomes inevitable. Materiel managers who regularly monitor key statistics, such as non-salary expenses per adjusted occupied bed, days in accounts payable, inventory dollars per adjusted occupied bed and so forth, can recognize the warning signs and take appropriate measures. Corrective actions can include reducing inventory levels, renegotiating contracts and leases, rebidding key contracts and supply items and extending purchase payment terms. A case study shows how a medical center experiencing weak performance implemented expense reductions in utilization, contracts, purchase costs/rebidding and inventory for substantial savings.

Sachs PR

1993-04-01

354

Peer response to messages of distress.  

UK PubMed Central (United Kingdom)

BACKGROUND: Suicidal young adults often confide their distress to peers. It is unclear, however, what types of assistance a friend may offer in response to various symptoms of distress as well as whether the sex of either individual affects responses. AIMS: We examined open-ended responses to e-mail vignettes from a fictitious friend exhibiting depressed, irritable, or overtly suicidal communications. METHOD: College student participants (n = 106) read e-mail messages from a fictitious friend, to which they composed a reply. Replies were coded to reflect the presence/absence of mention of professional help, problem-oriented (personal) help, and social support. RESULTS: Problem-oriented help was offered the most across conditions; professional help was offered least in response to depressed or irritable vignettes. Women were more likely to offer any type of help than men. Patterns of help-giving and sex differences in help-giving varied by condition. CONCLUSIONS: Results indicate students' preferences for solving peer problems personally rather than professionally. Campus prevention and intervention efforts should focus on enhancing students' peer support and referral skills.

Barton AL; Hirsch JK; Lovejoy MC

2013-01-01

355

Refining the measurement of distress intolerance.  

UK PubMed Central (United Kingdom)

Distress intolerance is an important transdiagnostic variable that has long been implicated in the development and maintenance of psychological disorders. Self-report measurement strategies for distress intolerance (DI) have emerged from several different models of psychopathology and these measures have been applied inconsistently in the literature in the absence of a clear gold standard. The absence of a consistent assessment strategy has limited the ability to compare across studies and samples, thus hampering the advancement of this research agenda. This study evaluated the latent factor structure of existing measures of DI to examine the degree to which they are capturing the same construct. Results of confirmatory factor analysis in three samples totaling 400 participants provided support for a single-factor latent structure. Individual items of these four scales were then correlated with this factor to identify those that best capture the core construct. Results provided consistent support for 10 items that demonstrated the strongest concordance with this factor. The use of these 10 items as a unifying measure in the study of DI and future directions for the evaluation of its utility are discussed.

McHugh RK; Otto MW

2012-09-01

356

Refining the measurement of distress intolerance.  

Science.gov (United States)

Distress intolerance is an important transdiagnostic variable that has long been implicated in the development and maintenance of psychological disorders. Self-report measurement strategies for distress intolerance (DI) have emerged from several different models of psychopathology and these measures have been applied inconsistently in the literature in the absence of a clear gold standard. The absence of a consistent assessment strategy has limited the ability to compare across studies and samples, thus hampering the advancement of this research agenda. This study evaluated the latent factor structure of existing measures of DI to examine the degree to which they are capturing the same construct. Results of confirmatory factor analysis in three samples totaling 400 participants provided support for a single-factor latent structure. Individual items of these four scales were then correlated with this factor to identify those that best capture the core construct. Results provided consistent support for 10 items that demonstrated the strongest concordance with this factor. The use of these 10 items as a unifying measure in the study of DI and future directions for the evaluation of its utility are discussed. PMID:22697451

McHugh, R Kathryn; Otto, Michael W

2011-12-20

357

A source mixing model to apportion PAHs from coal tar and asphalt binders in street pavements and urban aquatic sediments.  

Science.gov (United States)

Present-day and more than 30 years old road and footpath pavements from Auckland, New Zealand were analysed for PAHs to test the hypothesis that coal tar based pavement binders contribute to unusually high PAH concentrations in adjacent stream and estuarine sediments. Total PAH (?(28)PAH) concentrations in the dichloromethane-soluble fraction ("binder"), comprising 5-10% of pavement mass, were as high as 200,000 mgkg(-1) (10,000 mgkg(-1) in binder+aggregate). Older and deeper pavement layers were strongly pyrogenic, whereas pavement layers from recently sealed roads had a more petrogenic composition and more than 1000 times lower ?(28)PAH concentrations. Source identification analysis using three PAH isomer ratio pairs (benz(a)anthracene/(benz(a)anthracene+chrysene); benzo(a)pyrene/(benzo(a)pyrene+benzo(e)pyrene); and indeno(1,2,3-cd)pyrene/(indeno(1,2,3-cd)pyrene+benzo(g,h,i)perylene) revealed low PAH (bitumen) pavements to have consistently lower isomer ratios than high PAH (coal tar) samples. Moreover, pavement data for one isomer ratio (e.g. benzo(a)pyrene/(benzo(a)pyrene+benzo(e)pyrene) were highly correlated with those of another isomer ratio (e.g. benz(a)anthracene/(benz(a)anthracene+chrysene) and were bounded at their lower and higher extremes by the characteristics of pure bitumen and coal tar, respectively, suggesting that PAH composition of a given pavement sample could be accounted for by conservative mixing between coal tar and bitumen as source materials. A concentration-weighted mixing model, with coal tar and bitumen as source materials, explained more than 80% of the variance in isomer ratios and enveloped the entire PAH compositional and concentration range encountered. PAH composition and concentrations in adjacent stream sediments (> 15 mgkg(-1) dry weight) were consistent with diluted coal tar material as a principal PAH source. Due to the very high PAH concentrations of coal tar, a coal tar content of as little as 0.01% of total sediment mass can account for more than 90% of PAH concentrations in adjacent stream sediments. PMID:20843538

Ahrens, Michael J; Depree, Craig V

2010-09-16

358

Further developments in self-fertilising geotextiles for use in pervious pavements.  

Science.gov (United States)

Geotextiles incorporating inorganic nutrients (particularly phosphorous) to enhance the growth of oil degrading microoganisms when geotextiles are used in pervious pavement applications have been shown to be effective in the past. However the cost and manufacturing difficulties have been a barrier to their use. A polypropylene random mat geotextile incorporating an alternative polymer additive as a source of phosphorus has been investigated as a potential self-fertilising geotextile. Experiments are reported which investigate nutrient leach rates, biofilm formation and biodegradation activity. PMID:22214088

Newman, A P; Nnadi, E O; Duckers, L J; Cobley, A J

2011-01-01

359

Examining Victimization and Psychological Distress in Transgender College Students  

Science.gov (United States)

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

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

2011-01-01

360

Upper oesophageal foreign body with acute respiratory distress.  

UK PubMed Central (United Kingdom)

Foreign body (FB) ingestion, a common and serious problem in children can present with a wide variety of symptoms. Oesophageal FB leading to severe acute respiratory distress is uncommon and requires urgent surgical intervenetion. We report an 8-month-old female child who presented with severe respiratory distress to casualty and was found to have a FB in her upper oesophagus.

Singh A; Panda SS; Panda M; Srinivas M

2013-01-01

 
 
 
 
361

Role occupancy, role quality, and psychological distress, in Chinese women  

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study explored the associations between role occupancy, role quality and psychological distress in 897 Chinese women in Hong Kong. Results showed that employed as compared to nonemployed women reported a lower level of psychological distress. Never married as compared to married women, and moth...

Tang, CSK; Lee, AM; Tang, T; Cheung, FM

362

Measuring moral distress in pharmacy and clinical practice  

DEFF Research Database (Denmark)

This article presents the development, validation and application of an instrument to measure everyday moral distress in different health care settings. The concept of moral distress has been discussed and developed over 20 years. A few instruments have been developed to measure it, predominantly in nursing. The instrument presented here consists of two factors: level of moral distress, and tolerance/openness towards moral dilemmas. It was tested in four medical departments and three pharmacies, where 259 staff members completed a questionnaire. The two factors were found to be reliable. Differences in levels of moral distress were found between pharmacies and clinical departments, and between the youngest and oldest age groups; departmental staff and the youngest group experienced higher levels of moral distress. Departments reported less tolerance/openness towards moral dilemmas than pharmacies. The instrument needs to be tested further, but its strengths are the focus on everyday ethical dilemmas and its usefulness in different health care settings.

Kälvemark Sporrong, Sofia Beatrice; Höglund, Anna T

2006-01-01

363

Adolescent Identity Development and Distress in a Clinical Sample.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The purpose of this study was to examine the relationships of identity development and identity distress to psychological adjustment within adolescents affected by psychological problems. METHOD: Participants included 88 adolescents (43.2% female) ranging from 11 to 20 years of age who were receiving services from a community mental health center. RESULTS: A high proportion of the participants (22.7%) met the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition Text Revision criteria for Identity Problem. Regression analyses found psychopathology symptom score was associated with identity distress, identity exploration, and identity commitment, while identity distress was only related to psychopathology symptom score and not the other two identity variables. CONCLUSIONS: Adolescents with a clinical diagnosis may report significant levels of identity distress. Given that the relationship between psychopathology and identity distress may be reciprocal, assessing for identity issues might be prudent when conducting clinical diagnostic interviews and useful in treatment planning.

Wiley RE; Berman SL

2013-06-01

364

Distress among young adult cancer survivors: a cohort study.  

UK PubMed Central (United Kingdom)

PURPOSE: Being diagnosed with cancer as a young adult can lead to significant psychological distress and impaired quality of life. Compared to children and older adults diagnosed with cancer, fewer studies have addressed psychological distress among young adult cancer survivors. This study sought to identify the prevalence of, and factors associated with, distress among young adult cancer survivors (ages 18-39). METHODS: Young adult cancer survivors (N = 335, mean age = 31.8, women = 68.4%) were recruited from an online research panel and stratified by cohort (time postactive treatment: 0-12, 13-24, and 25-60 months). Participants completed measures assessing demographic and clinical characteristics, global impact of cancer, cancer-related education and work interruption, and cancer-specific distress using the impact of event scale (IES). RESULTS: The mean score on the IES (M = 31.0, range = 0-75) was above the cut point of 20, suggesting clinically elevated distress. Analysis of covariance revealed significant main effects for cohort, global impact and cancer-related education/work interruption, and an interaction between cohort and cancer-related education/work interruption on distress. Although there was no significant effect of education/work interruption on distress for those in the 0-12 month cohort (p = .88), survivors in the 13-24 and 25-60 month cohorts reporting education/work interruption were significantly more distressed than those not reporting education/work interruption in the respective cohorts (p < .05). CONCLUSIONS: Young adult cancer survivors face unique challenges. These data underscore the importance of attending to cancer-related distress beyond the completion of treatment and may help inform targeted interventions to prevent or reduce significant distress and related sequelae in this population.

Yanez B; Garcia SF; Victorson D; Salsman JM

2013-09-01

365

The effectiveness of bibliotherapy in alleviating tinnitus-related distress.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The present study examined the efficacy of bibliotherapy in assisting individuals experiencing distress related to tinnitus. METHODS: One hundred sixty-two tinnitus sufferers from Australia participated in a study designed to examine the effectiveness of a cognitive-behaviorally based self-help book in reducing distress. To maximize the ecological validity of the findings, we excluded no individuals interested in treatment for tinnitus-related distress. RESULTS: The experimental condition lost 35% of participants at postassessment, compared to 10% in the control group. In an analysis of participants who completed postintervention assessment, those assigned to the intervention condition, who received a tinnitus self-help book, showed significantly less tinnitus-related distress and general distress 2 months later compared to those assigned to the waiting list control condition. The intervention group's reduction in tinnitus-related distress and general distress from preintervention to postintervention 2 months later was significant, and these participants maintained a significant reduction in distress on follow-up 4 months after they received the tinnitus self-help book. A long-term follow-up of all participants, who at that time had received the book at least a year previously, showed a significant reduction in tinnitus distress. Although these group differences and pre-post changes were significant, effect sizes were small. Intention-to-treat analyses showed no significant effect for between-groups analyses, but did show a significant effect for the 1-year follow-up pre-post analysis. CONCLUSION: Information on the effectiveness of using a self-help book, without therapist assistance, in alleviating distress is important, as bibliotherapy can provide inexpensive treatment that is not bound by time or place.

Malouff JM; Noble W; Schutte NS; Bhullar N

2010-03-01

366

Longitudinal relationships between workplace bullying and psychological distress.  

UK PubMed Central (United Kingdom)

OBJECTIVES: The aims of this study were to examine reciprocal longitudinal associations between exposure to workplace bullying and symptoms of psychological distress and to investigate how self-labeled victimization from bullying explains the effects of bullying on health. METHODS: Logistic regression analysis was employed to examine the longitudinal relationships between workplace bullying and psychological distress in a representative cohort sample of 1775 Norwegian employees. The time-lag between baseline and follow-up was two years. Exposure to bullying behavior was measured with the revised version of the Negative Acts Questionnaire. Perceived victimization from bullying was measured by a single self-labeling question. Psychological distress was measured with the 25-item Hopkins Symptom Checklist. All variables were measured at both baseline and follow-up. RESULTS: After adjustment for psychological distress at baseline, exposure to bullying behavior [odds ratio (OR) 1.68, 95% confidence interval (95% CI) 1.07-2.62) was found to predict subsequent psychological distress. This effect of bullying behaviors disappeared when victimization from bullying (OR 2.47, 95% CI 1.17-5.22) was entered into the regression. Both psychological distress (OR 2.49, 95% CI 1.64-3.80) and victimization (OR 2.61, 95% CI 1.42-4.81) at baseline were associated with increased risks of being a target of bullying behaviors at follow-up. Psychological distress (OR 2.51, 95% CI 1.39-4.52) and bullying behaviors (OR 2.95, 95% CI 1.39-4.52) at follow-up were associated with victimization. CONCLUSION: The mutual relationship between bullying and psychological distress indicates a vicious circle where bullying and distress reinforce their own negative effects. This highlights the importance of early interventions to stop workplace bullying and provide treatment options to employees with psychological distress.

Nielsen MB; Hetland J; Matthiesen SB; Einarsen S

2012-01-01

367

The measure of psychological distress in cancer patients: the use of Distress Thermometer in the Oncological Rehabilitation Center of Florence.  

UK PubMed Central (United Kingdom)

GOALS OF WORK: Distress in cancer patients is common. In the last years, several studies have used the single-item Distress Thermometer (DT) as a screening tool for psychological distress in cancer patients. The primary objective of this study was to determine the optimal cutoff score on the DT for detecting psychological distress in cancer patients attending a rehabilitation center, by comparing the DT's scores with those of the Psychological Distress Inventory (PDI). The second aim was to explore the effectiveness of the DT as a screening tool for psychological distress in rehabilitative oncological setting. PATIENTS AND METHODS: The sample study totaled 290 patients who were recruited from patients attending the Oncological Rehabilitation Center of Florence for the first time between January and December 2007. Patients were administered the DT along with the Problem List (PL) and the PDI as the gold standard against which the DT was compared. MAIN RESULTS: The area under the receiver operating characteristics curve was 0.84 [95%CI 0.80-0.89]. The optimal DT cutoff score for identifying distressed cancer patients would be at or above 7 (sensitivity = 0.73; specificity = 0.82). Patients whose DT score was 7 or above were more likely to report problems in all issues on the PL. CONCLUSIONS: The combination of DT and PL could be a practicable screening instrument for assessing the extent and the kind of distress also in rehabilitative oncological patients. On the other hand, the choice of the DT should be evaluated by clinicians.

Bulli F; Miccinesi G; Maruelli A; Katz M; Paci E

2009-07-01

368

Sharing, Liking, Commenting, and Distressed? The Pathway Between Facebook Interaction and Psychological Distress.  

UK PubMed Central (United Kingdom)

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

Chen W; Lee KH

2013-06-01

369

Sharing, Liking, Commenting, and Distressed? The Pathway Between Facebook Interaction and Psychological Distress.  

Science.gov (United States)

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

Chen, Wenhong; Lee, Kye-Hyoung

2013-06-01

370

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

UK PubMed Central (United Kingdom)

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

Chen W; Lee KH

2013-10-01

371

Chloride Released from Three Permeable Pavement Surfaces after Winter Salt Application  

Science.gov (United States)

EPA does not classify chloride as a priority pollutant. It is often unregulated in stormwater runoff but has been a target stressor for Total Maximum Daily Load (TMDL) allotments developed for multiple waterbodies. Previous research has shown that road salt applications increas...

372

Performance Evaluation of Hot and Cold Pour Crack Sealing Treatments on Asphalt Surfaced Pavements (Revised).  

Science.gov (United States)

This study is a continuation of an ongoing process of monitoring performance of treatment procedures using two types of crack sealants. The main objective of the analysis in this report is to compare the long-term performance of hot pour sealants to that ...

Y. Yildirim A. Qatan T. W. Kennedy

2003-01-01

373

An unusual tumour causing neonatal respiratory distress.  

UK PubMed Central (United Kingdom)

PROBLEM: We present the case of a term neonate referred shortly after birth because of breathing and feeding difficulties. METHODOLOGY: Fiber-endoscopic examination of the nasal cavity showed a pendulating mass in the nasopharynx. RESULTS: A complete surgical resection was performed and the baby recovered completely. Microscopic examination of the mass showed an overlying non-keratinized squamous cell lining with an atypical cell population in some fragments. Histological features were compatible with a high-grade epithelial tumour like a midline carcinoma, but a final diagnosis of a salivary gland anlage tumour was established. CONCLUSION: Flexible fiber endoscopy is the method of choice for examining the nasal passages and oropharynx in neonates with respiratory distress. Congenital salivary gland anlage tumour is a rare cause of neonatal nasal obstruction; it is benign and complete excision results in a cure. Histologically, it may mimic a malignant tumour owing to the high mitotic index.

Marien A; Maris M; Verbeke S; Creytens D; Verlooy J; Van Reempts P; Boudewyns A

2012-01-01

374

Psychiatric distress in systemic lupus erythematosus outpatients.  

UK PubMed Central (United Kingdom)

A belief exists that systemic lupus erythematosus (SLE) patients have more psychiatric symptoms than patients with most other medical illnesses and that they often are as psychiatrically disturbed as psychiatric patient groups. These beliefs did not prove to be true for SLE outpatients. Twenty-two outpatients with SLE, 81 general medical outpatients, and 40 psychiatric outpatients were screened with psychometrically validated self-report instruments designed to assess psychiatric symptoms and stress. The SLE outpatients' psychiatric symptoms and stresses were much more similar to those reported by general medical outpatients, rather than by psychiatric outpatients, except in a few areas, and SLE patients were significantly less distressed than psychiatric patients in all areas except those relating directly to their SLE.

Mitchell WD; Thompson TL 2nd

1990-01-01

375

Politics, economic distress mark Rmoga sessions  

International Nuclear Information System (INIS)

This paper reports that election year energy politics clashed with economic distress at Rocky Mountain Oil and Gas Association's annual meeting in Denver early this month. Energy Sec. James D Watkins used the occasion to hail omnibus energy legislation passed by a House-Senate conference committee just hours before he spoke. But not all producers and refiners in the audience shared his enthusiasm for the energy bill, a hard-won Bush administration goal that many Rmoga members doubt will help this industry much. Several of them privately expressed dismay over Watkins' praise, delivered to a beleaguered oil and gas group, of Department of Energy research programs boosting clean coal technology and battery powered vehicles.

1992-01-01

376

Politics, economic distress mark Rmoga sessions  

Energy Technology Data Exchange (ETDEWEB)

This paper reports that election year energy politics clashed with economic distress at Rocky Mountain Oil and Gas Association's annual meeting in Denver early this month. Energy Sec. James D Watkins used the occasion to hail omnibus energy legislation passed by a House-Senate conference committee just hours before he spoke. But not all producers and refiners in the audience shared his enthusiasm for the energy bill, a hard-won Bush administration goal that many Rmoga members doubt will help this industry much. Several of them privately expressed dismay over Watkins' praise, delivered to a beleaguered oil and gas group, of Department of Energy research programs boosting clean coal technology and battery powered vehicles.

1992-10-12

377

Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement.  

Science.gov (United States)

Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10(-4), as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10(-5). Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0-6 years of age). PMID:23181746

Williams, E Spencer; Mahler, Barbara J; Van Metre, Peter C

2013-01-03

378

Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement.  

UK PubMed Central (United Kingdom)

Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10(-4), as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10(-5). Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0-6 years of age).

Williams ES; Mahler BJ; Van Metre PC

2013-01-01

379

The synergy of permeable pavements and geothermal heat pumps for stormwater treatment and reuse.  

UK PubMed Central (United Kingdom)

The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff.

Tota-Maharaj K; Scholz M; Ahmed T; French C; Pagaling E

2010-12-01

380

The synergy of permeable pavements and geothermal heat pumps for stormwater treatment and reuse.  

Science.gov (United States)

The use of permeable pavement systems with integrated geothermal heat pumps for the treatment and recycling of urban runoff is novel and timely. This study assesses the efficiency of the combined technology for controlled indoor and uncontrolled outdoor experimental rigs. Water quality parameters such as biochemical oxygen demand, nutrients, total viable heterotrophic bacteria and total coliforms were tested before and after treatment in both rigs. The water borne bacterial community genomic deoxyribonucleic acid (DNA) was analyzed by polymerase chain reaction (PCR) amplification followed by denaturing gradient gel electrophoresis (DGGE) and was further confirmed by DNA sequencing techniques. Despite the relatively high temperatures in the indirectly heated sub-base of the pavement, potentially pathogenic organisms such as Salmonella spp., Escherichia coli, faecal Streptococci and Legionella were not detected. Moreover, mean removal rates of 99% for biochemical oxygen demand, 97% for ammonia-nitrogen and 95% for orthophosphate-phosphates were recorded. This research also supports decision-makers in assessing public health risks based on qualitative molecular microbiological data associated with the recycling of treated urban runoff. PMID:21275249

Tota-Maharaj, K; Scholz, M; Ahmed, T; French, C; Pagaling, E

2010-12-14

 
 
 
 
381

Porous Pavement and Water Quality: Investigation of a Parking Lot and Its Potential Impact on Subsurface Water.  

Science.gov (United States)

A non-polymer modified porous pavement parking lot on the University of Rhode Island campus was recently constructed in an environmentally sensitive area, i.e., in close proximity to a drinking water well field. The objective of this study was to investig...

T. B. Boving M. H. Stolt J. Augenstern B. Brosnan

2006-01-01

382

Sensitivity Analysis of Heavy Pavement Design for a Container Terminal Area, Case Study: Port of Gaza, Palestine  

Directory of Open Access Journals (Sweden)

Full Text Available This study focuses on the sensitivity analysis of various design parameters for heavy-duty pavement for container terminal areas using Airport Pavement Structural Design System (APSDS) to yield an optimal design solution. APSDS is based on layered elastic theory, which was introduced into airfield design practice with the release of the computer program LEDFAA (Layered Elastic Design, Federal Aviation Administration). In this study, the pavement structure was found very sensitive to design parameters, where 15-60 mm more in base thickness was increased the design life twice. A reduction of base thickness was 27% by changing the handling system from rubber tyred gantry crane system to straddle carrier system and a reduction of 42-76% of base thickness by changing the interface condition at the bottom of base layer from smooth to rough. Other effects of design parameters such as lateral wandering distribution, container weight frequency, variation of elastic modulus for concrete block pavers and sub-grade are discussed. Also various construction materials were used and several combinations of base and sub-base materials were analysed to be able to select the most economical pavement structures.

Mazen Abualtayef; Ronald De Heer; Masamitsu Kuroiwa; Yuhei Matsubara; Ahmed Khaled Seif

2007-01-01

383

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

Science.gov (United States)

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

384

Hot-Mix Asphalt Pavement Construction Report for the 1993-2000 FHWA Accelerated Loading Facility Project.  

Science.gov (United States)

The Federal Highway Administration is conducting studies to validate Superpave binder and mixture tests using its Accelerated Loading Facility (ALF). The ALF is a full-scale pavement testing machine that applies one-half of a single rear truck axle load. ...

K. D. Stuart R. P. Izzo

1999-01-01

385

Noise abatement and traffic safety: The trade-off of quieter engines and pavements on vehicle detection.  

UK PubMed Central (United Kingdom)

Road traffic sounds are a major source of noise pollution in urban areas. But recent developments such as low noise pavements and hybrid/electric engine vehicles cast an optimistic outlook over such an environmental problem. However, it can be argued that engine, tire, and road noise could be relevant sources of information to avoid road traffic conflicts and accidents. In this paper, we analyze the potential trade-offs of traffic-noise abatement approaches in an experimental study, focusing for the first time on the impact and interaction of relevant factors such as pavement type, vehicle type, listener's age, and background noise, on vehicle detection levels. Results reveal that vehicle and pavement type significantly affect vehicle detection. Age is a significant factor, as both younger and older people exhibit lower detection levels of incoming vehicles. Low noise pavements combined with all-electric and hybrid vehicles might pose a severe threat to the safety of vulnerable road users. All factors interact simultaneously, and vehicle detection is best predicted by the loudness signal-to-noise ratio.

Mendonça C; Freitas E; Ferreira JP; Raimundo ID; Santos JA

2013-03-01

386

Empirical Model Evaluation of Sedimentary Residual Soil Bearing Capacity from Surface Wave Method  

Directory of Open Access Journals (Sweden)

Full Text Available Bearing capacity of the subgrade layers has significant influence on the performance of the overall pavement structure. In this study, the Spectral Analysis of Surface Wave (SASW) method was used for assessing the stiffness of pavement subgrade layer. The SASW method employed was based on the Rayleigh-wave propagation. Using the phase difference data of Rayleigh waves, the experimental dispersion curve of phase velocity was obtained. Consequently, inversion process was conducted to obtain the shear wave velocity and the dynamic modulus of the pavement structure. The results showed that some empirical models of the shear wave velocity and the dyamic elastic modulus versus soil bearing capacity of the California bearing ratio (CBR) and dynamic cone penetrometer (DCP) were derived. Good agreement was also found between these empirical models compared to that of previous studies

Sri Atmaja Rosyidi; Mohd. Raihan Taha; Khairul Anuar Mohd Nayan

2010-01-01

387

Food insecurity, childhood illness and maternal emotional distress in Ethiopia.  

UK PubMed Central (United Kingdom)

OBJECTIVE: The relationship between food insecurity, maternal emotional distress and childhood morbidity in resource-poor settings is not well clarified. The present study aimed to assess independent associations between household food insecurity and childhood morbidity and potential modifications by maternal emotional distress. DESIGN: A cross-sectional survey. A food security scale was used to assess household food insecurity; maternal reports were used to assess recent childhood illness; and the Hopkins Symptom Checklist was used to assess symptoms of emotional distress among mothers. SETTING: The Oromia Region, Ethiopia (rural area). SUBJECTS: A total of 936 mother-child pairs. RESULTS: Of 936 children assessed, 22·4% had experienced diarrhoea, 20·7% had cough and 21·5% had fever in the 2 weeks preceding the interview. Household food insecurity was reported by 39% of mothers. Greater food insecurity and greater maternal emotional distress were each independently associated with higher prevalence of cough and fever. Among mothers with low emotional distress, food insecurity was associated with a 2·3 times greater odds of diarrhoea in their children. CONCLUSIONS: Household food insecurity may increase the risk of childhood illness in rural Ethiopia, and children having mothers with greater emotional distress may be at highest risk. These findings highlight the importance of strengthening policy initiatives aimed at reducing the high prevalence of food insecurity and emotional distress in Ethiopia.

Anderson LC; Tegegn A; Tessema F; Galea S; Hadley C

2012-04-01

388

Discourse analytic research on mental distress: A critical overview.  

UK PubMed Central (United Kingdom)

Background. Discourse analytic approaches to mental distress have been developed in the last two decades as part of the broader social constructionist movement in psychology. Aims. The paper reviews existing discourse analytic studies on issues pertaining to mental distress, aiming to identify strengths and gaps in the existing literature as well as to assess their contribution to conceptualizing and managing distress. Method. Discourse analytic and social constructionist studies of different aspects of mental distress, conducted within the field of psychology, were identified and reviewed. Results. The studies reviewed have been organized in four themes: (a) exploring users' accounts and experiences, (b) examining professional accounts and practices, (c) focusing on mental health-related public texts and (d) deconstructing clinical categories. Conclusions. The main function of discourse analytic studies on mental distress has been to highlight the historically contingent and socially constructed character of professional forms of knowledge and practice. More specifically, this research trend has highlighted the discursive resources drawn upon to conceptualize mental distress, the discursive practices through which specific versions of distress are constructed and the discursive effects of these constructions for institutions, subjectivity and social practices.

Georgaca E

2013-01-01

389

Psychological distress in Ghana: associations with employment and lost productivity.  

UK PubMed Central (United Kingdom)

OBJECTIVES: Mental health disorders account for 13% of the global burden of disease, a burden that low-income countries are generally ill-equipped to handle. Research evaluating the association between mental health and employment in low-income countries, particularly in sub-Saharan Africa, is limited. We address this gap by examining the association between employment and psychological distress. METHODS: We analyzed data from the Ghana Socioeconomic Panel Survey using logistic regression (N?=?5,391 adults). In multivariable analysis, we estimated the association between employment status and psychological distress, adjusted for covariates. We calculated lost productivity from unemployment and from excess absence from work that respondents reported was because of their feelings of psychological distress. FINDINGS: Approximately 21% of adults surveyed had moderate or severe psychological distress. Increased psychological distress was associated with increased odds of being unemployed. Men and women with moderate versus mild or no psychological distress had more than twice the odds of being unemployed. The association of severe versus mild or no distress with unemployment differed significantly by sex (P-value for interaction 0.004). Among men, the adjusted OR was 12.4 (95% CI: 7.2, 21.3), whereas the association was much smaller for women (adjusted OR?=?3.8, 95% CI: 2.5, 6.0). Extrapolating these figures to the country, the lost productivity associated with moderate or severe distress translates to approximately 7% of the gross domestic product of Ghana. CONCLUSIONS: Psychological distress is strongly associated with unemployment in Ghana. The findings underscore the importance of addressing mental health issues, particularly in low-income countries.

Canavan ME; Sipsma HL; Adhvaryu A; Ofori-Atta A; Jack H; Udry C; Osei-Akoto I; Bradley EH

2013-01-01

390

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

Directory of Open Access Journals (Sweden)

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

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

2009-01-01

391

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

Scientific Electronic Library Online (English)

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

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

2009-12-01

392

Prevention of psychological distress in persons with inflammatory bowel disease.  

UK PubMed Central (United Kingdom)

This paper presents an overview of IBD with a critical analysis of the causes and effects of psychological distress in persons with this illness. Based on this literature, risk factors for the development of psychological distress are delineated. It is recognition of these risk factors for the development and the early signs of psychological distress in this population that can enable nurses to prevent this unfortunate psychosocial consequence of this disease. Preventive interventions discussed include the following: treating comorbid psychiatric illness, enhancing problem-solving coping, facilitating mourning and grieving, reducing stress, enhancing the positive appraisal of uncertainty, increasing personal control, increasing social support, and educating patients, families, and others.

Dudley-Brown S

2002-06-01

393

Psychological distress in childhood trauma survivors who abuse drugs.  

UK PubMed Central (United Kingdom)

The relationships between the level of childhood maltreatment and current psychological distress were examined in a community sample of 676 substance abusing men and women using a validated self-report instrument (the Childhood Trauma Questionnaire) designed to measure physical, emotional, and sexual abuse and physical and emotional neglect. Current levels of self-reported psychological distress/symptoms were measured using a 53-item Brief Symptom Inventory. Prevalence of early trauma ranged from 44% for emotional neglect to 65% for sexual abuse. The severity of all forms of childhood maltreatment were directly associated with current psychological distress.

Medrano MA; Hatch JP; Zule WA; Desmond DP

2002-01-01

394

Psychological distress in childhood trauma survivors who abuse drugs.  

Science.gov (United States)

The relationships between the level of childhood maltreatment and current psychological distress were examined in a community sample of 676 substance abusing men and women using a validated self-report instrument (the Childhood Trauma Questionnaire) designed to measure physical, emotional, and sexual abuse and physical and emotional neglect. Current levels of self-reported psychological distress/symptoms were measured using a 53-item Brief Symptom Inventory. Prevalence of early trauma ranged from 44% for emotional neglect to 65% for sexual abuse. The severity of all forms of childhood maltreatment were directly associated with current psychological distress. PMID:11853127

Medrano, Martha A; Hatch, John P; Zule, William A; Desmond, David P

2002-01-01

395

Lung tissue remodeling in the acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

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

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

2003-01-01

396

Lung tissue remodeling in the acute respiratory distress syndrome  

Directory of Open Access Journals (Sweden)

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

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

2003-01-01

397

Effects of screening for psychological distress on patient outcomes in cancer: a systematic review.  

UK PubMed Central (United Kingdom)

OBJECTIVE: Several practice guidelines recommend routine screening for psychological distress in cancer care. The objective was to evaluate the effect of screening cancer patients for psychological distress by assessing the (1) effectiveness of interventions to reduce distress among patients identified as distressed; and (2) effects of screening for distress on distress outcomes. METHODS: CINAHL, Cochrane, EMBASE, ISI, MEDLINE, PsycINFO, and SCOPUS databases were searched through April 6, 2011 with manual searches of 45 relevant journals, reference list review, citation tracking of included articles, and trial registry reviews through June 30, 2012. Articles in any language on cancer patients were included if they (1) compared treatment for patients with psychological distress to placebo or usual care in a randomized controlled trial (RCT); or (2) assessed the effect of screening on psychological distress in a RCT. RESULTS: There were 14 eligible RCTs for treatment of distress, and 1 RCT on the effects of screening on patient distress. Pharmacological, psychotherapy and collaborative care interventions generally reduced distress with small to moderate effects. One study investigated effects of screening for distress on psychological outcomes, and it found no improvement. CONCLUSION: Treatment studies reported modest improvement in distress symptoms, but only a single eligible study was found on the effects of screening cancer patients for distress, and distress did not improve in screened patients versus those receiving usual care. Because of the lack of evidence of beneficial effects of screening cancer patients for distress, it is premature to recommend or mandate implementation of routine screening.

Meijer A; Roseman M; Delisle VC; Milette K; Levis B; Syamchandra A; Stefanek ME; Stewart DE; de Jonge P; Coyne JC; Thombs BD

2013-07-01

398

Rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems in the presence of trees.  

UK PubMed Central (United Kingdom)

The retrofitting of sustainable drainage systems (SuDS) such as permeable pavements is currently undertaken ad hoc using expert experience supported by minimal guidance based predominantly on hard engineering variables. There is a lack of practical decision support tools useful for a rapid assessment of the potential of ecosystem services when retrofitting permeable pavements in urban areas that either feature existing trees or should be planted with trees in the near future. Thus the aim of this paper is to develop an innovative rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems close to trees. This unique tool proposes the retrofitting of permeable pavements that obtained the highest ecosystem service score for a specific urban site enhanced by the presence of trees. This approach is based on a novel ecosystem service philosophy adapted to permeable pavements rather than on traditional engineering judgement associated with variables based on quick community and environment assessments. For an example case study area such as Greater Manchester, which was dominated by Sycamore and Common Lime, a comparison with the traditional approach of determining community and environment variables indicates that permeable pavements are generally a preferred SuDS option. Permeable pavements combined with urban trees received relatively high scores, because of their great potential impact in terms of water and air quality improvement, and flood control, respectively. The outcomes of this paper are likely to lead to more combined permeable pavement and tree systems in the urban landscape, which are beneficial for humans and the environment.

Scholz M; Uzomah VC

2013-08-01

399

Rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems in the presence of trees.  

Science.gov (United States)

The retrofitting of sustainable drainage systems (SuDS) such as permeable pavements is currently undertaken ad hoc using expert experience supported by minimal guidance based predominantly on hard engineering variables. There is a lack of practical decision support tools useful for a rapid assessment of the potential of ecosystem services when retrofitting permeable pavements in urban areas that either feature existing trees or should be planted with trees in the near future. Thus the aim of this paper is to develop an innovative rapid decision support tool based on novel ecosystem service variables for retrofitting of permeable pavement systems close to trees. This unique tool proposes the retrofitting of permeable pavements that obtained the highest ecosystem service score for a specific urban site enhanced by the presence of trees. This approach is based on a novel ecosystem service philosophy adapted to permeable pavements rather than on traditional engineering judgement associated with variables based on quick community and environment assessments. For an example case study area such as Greater Manchester, which was dominated by Sycamore and Common Lime, a comparison with the traditional approach of determining community and environment variables indicates that permeable pavements are generally a preferred SuDS option. Permeable pavements combined with urban trees received relatively high scores, because of their great potential impact in terms of water and air quality improvement, and flood control, respectively. The outcomes of this paper are likely to lead to more combined permeable pavement and tree systems in the urban landscape, which are beneficial for humans and the environment. PMID:23697848

Scholz, Miklas; Uzomah, Vincent C

2013-05-19

400

Fluid management in acute respiratory distress syndrome.  

UK PubMed Central (United Kingdom)

PURPOSE OF REVIEW: Fluid management is one of the most important measures shown to impact acute respiratory distress syndrome (ARDS) outcomes. This review summarizes the current strategies aimed at evaluating and modulating lung fluid balance. RECENT FINDINGS: Multiple recent studies have shown that a conservative fluid management in ARDS patients had beneficial effects on morbidity and mortality. These findings were replicated also in different patient populations assumed to have potential deleterious effects from this approach. So far, only one retrospective study raised the possibility of impaired cognitive function in ARDS patients managed with a conservative fluid strategy. Thermodilution methods and serum biomarkers can be used to monitor lung fluid balance and guide therapy. Recent evidence has indicated significant detrimental effects associated with beta-2 agonists use in ARDS, despite a putative beneficial role in the resolution of alveolar edema seen in preliminary studies. SUMMARY: Dynamic monitoring of lung fluid balance needs to be implemented to guide fluid therapy in ARDS patients. A conservative fluid strategy seems safe and yields overall good clinical outcomes, but its impact on cognitive function needs to be evaluated in further studies. The role of colloids and other pharmacological agents deserves further investigation.

Neamu RF; Martin GS

2013-02-01