bluuebunny/crossref_metadata_2025 huggingface dataset:
A Theoretical and Empirical Analysis of Alternate Auction Policies for Search Advertisements
Authors: Balachander Subramanian , Kannan Karthik , Schwartz David G
Published: December 2009

In the online world, publishers place ads from advertisers adjacent to internet search results for a given keyword. To sell such advertising, web publishers auction multiple ad slots using a generalized second-price auction. In this paper, we compare two auction policies that publishers can use to determine the rank and payments of bidding advertisers. The first policy, the highest bid policy, ranks ads based on the bids submitted while the second policy, the highest profit policy, ranks ads based on the expected profit generated to the publisher. Interestingly, we find that the highest profit policy may generate lower publisher profits per keyword even though it uses more information. Subsequently, we use data from a search engine and empirically establish that the correlation between valuations and click through rates are positive, an important assumption in our theoretical model. This finding provides significant support for the theoretical results.
Technological Diversity and Cost Uncertainty
Authors: Krysiak Frank C.
Published: December 2009

In many industries, different technologies are used simultaneously for the production of a homogeneous good. Such diversification is socially beneficial, because it reduces the transmission of factor price volatility, like oil-price shocks, to consumer prices. Therefore, many countries have implemented policies aimed at increasing technological diversification. The question is whether such policies are necessary. We use a two-stage investment model to address this question in the setting of perfect competition and of a monopoly. We show that factor price uncertainty leads to diversification, if capital is not too expensive, and that this diversification is due to each firm investing in a diversified technology portfolio. An important implication of this form of diversification is that technological diversity is socially optimal, even in the case of a monopoly. Thus policy intervention is unnecessary and might even be detrimental.
Nutritional Hormesis and Aging
Authors: Hayes Daniel P.
Published: December 2009

Nutritional hormesis has the potential to serve as a pro-healthy aging intervention by reducing the susceptibility of the elderly to various chronic degenerative diseases and thereby extending human healthspan. Supportive evidence for nutritional hormesis arising from essential nutrients (vitamins and minerals), dietary pesticides (natural and synthetic), dioxin and other herbicides, and acrylamide will be reviewed and discussed.
The Dose Window for Radiation-Induced Protective Adaptive Responses
Authors: Mitchel Ronald E. J.
Published: December 2009

Adaptive responses to low doses of low LET radiation occur in all organisms thus far examined, from single cell lower eukaryotes to mammals. These responses reduce the deleterious consequences of DNA damaging events, including radiation-induced or spontaneous cancer and non-cancer diseases in mice. The adaptive response in mammalian cells and mammals operates within a certain window that can be defined by upper and lower dose thresholds, typically between about 1 and 100 mGy for a single low dose rate exposure. However, these thresholds for protection are not a fixed function of total dose, but also vary with dose rate, additional radiation or non-radiation stressors, tissue type and p53 functional status. Exposures above the upper threshold are generally detrimental, while exposures below the lower threshold may or may not increase either cancer or non-cancer disease risk.
Sorption of light hydrocarbons on clays from the Oligocene Kiscell Clay Formation, Hungary
Authors: Tóth Judit
Published: December 2009

Sorption of light hydrocarbons on clays from the Oligocene Kiscell Clay Formation, Hungary

Clays from Solymár (Hungary) were treated with volatile components of light hydrocarbon in order to investigate their ability to sorb these organic compounds. The clays were characterized using XRD, optical microscopy (thin sections) and CEC measurements. The contaminated samples were analyzed using ATD-GC-MS, Rock Eval and XRD. Volatilization of the fluid phase hydrocarbon was monitoring for 663 days. The quantity of volatilized hydrocarbon compounds reached 50.0-65.0% at the end of the experiment. All of the analyses indicate hydrocarbon pollution of the clay layers after the volatilization process. The gross compositions of the fluid and the sorbed phases are different; the total amount of cycloalkanes among the sorbed hydrocarbons is very low. The dominant sorbed components are toluene, xylenes, nC9, nC10, nC11 and nC7. Cyclohexane, methylcyclohexane, benzene, nC12 and nC13 also occur in lower concentrations. The geochemical and XRD results indicate that adsorption onto the external surfaces of the clay minerals was the main sorption process.
Remarks on the origin of cerussite in the Upper Silesian Zn-Pb deposits, Poland
Authors: Szczerba Marek , Sawłowicz Zbigniew
Published: December 2009

Remarks on the origin of cerussite in the Upper Silesian Zn-Pb deposits, Poland

Cerussite, the most important oxidized lead mineral in the Upper Silesian Zn-Pb deposits, occurs in two readily distinct types: fine-grained cerussite replacing galena in-situ and macrocrystalline cerussite filling open fractures and cavities. Microscopic observations and thermodynamic considerations lead to the conclusion that galena can be oxidized to lead carbonate directly, not necessarily through an intermediate sulphate phase. Locally present iron sulphides undergoing oxidation acidify solutions and provide ferric ions which are important oxidizing agents. In such microenvironments, anglesite can preferentially form.

Cerussite and galena commonly coexist together with non-oxidized zinc sulphides. It is difficult to explain such assemblages if galvanic couplings made of these two sulphides are not considered. These couplings are only formed when these two sulphides are in direct contact. In such an assemblage, galena undergoes oxidation, mostly to cerussite, and sphalerite is passivated. When there is no direct contact between sulphides, the galvanic couplings do not exist. Galena surfaces become covered by oxidation products which inhibit further oxidation. As such a cover does not form on sphalerite, it can be easily oxidized.
Development of a radiolabeled β-human chorionic gonadotropin
Authors: Jalilian Amir , Khoshdel Mohammad , Garousi Javad , Yousefnia Hassan , Hosseini Mohammad , Rajabifar Saeed , Sardari Daryoush
Published: December 2009

Development of a radiolabeled β-human chorionic gonadotropin

β-Human chorionic gonadotropin (β-hCG) was successively labeled with [67Ga]-gallium chloride after conjugation with freshly prepared diethylenetriaminepentaacetic acid dianhydride (ccDTPA). After solid phase purification of the radiolabeled hormone, high performance liquid chromatography showed radiochemical purity higher than 95 % under optimized conditions (specific activity = 22-23 TBq mM-1, labeling efficiency 80 %). Preliminaryin vivostudies (ID g-1, %) in male wild-type rats showed marked gonadal uptake of the tracer after 240 minutes in agreement with the biodistribution studies and reported β-hCG receptors. Target to blood ratios were 5.1 and 15.2 after 3 and 24 hours, respectively, while target to muscle ratios were 35 and 40 after 3 and 24 hours, respectively.
Chemical composition of endemic Centaurea austro-anatolica and studies of its antimicrobial activity against multi-resistant bacteria
Authors: Ugur Aysel , Sarac Nurdan , Ceylan Ozgur , Duru M.
Published: December 2009

Chemical composition of endemicCentaurea austro-anatolicaand studies of its antimicrobial activity against multi-resistant bacteria

Hexane, chloroform, ethyl acetate and ethanolic extracts of the aerial parts ofCentaurea austro-anatolicaHub.-Mor. (Asteraceae) were evaluated against microorganisms, including multiresistant bacteria, using a paper disc diffusion method. The chloroform extract exhibited significant antibacterial activity toward all bacteria tested. The chemical composition of the chloroform extract was determined by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The major compounds of the extract were caryophyllene oxide (21.32 %), spathulenol (10.86 %),n-tricosanol (9.58 %) and geranyl isovalerate (8.71 %).
Agarose Gel Electrophoresis - Applications in Clinical Chemistry
Authors: Giot Jean-Francois
Published: December 2009

Agarose Gel Electrophoresis - Applications in Clinical Chemistry

Agarose gel electrophoresis is a well established technique routinely used in clinical laboratories for screening protein abnormalities in various biological fluids (serum, urine, CSF). It is based on the principles of zone electrophoresis. Electrophoretograms are evaluated visually for the presence of quantitatively or qualitatively abnormal protein bands. The technique is used for electrophoresis of serum, urine, CSF proteins, enzymes (ALP, LDH and CK), lipoproteins and hemoglobin. Serum protein electrophoresis (SPE) is a very commonly used analytical method in clinical chemistry. Changes in the relative concentration of fractions allow easy recognition of pathological disorders associated with nephrotic syndrome, inflammatory reaction and hepatic diseases. SPE is a screening test for detecting the M component (MC). Immunofixation (IFE) with use of specific antisera allows detection of the type of MC. SPE is also a method for the quantification of MC and monitoring of disease that is essential for clinical evaluation and follow-up of patients with plasma cell disorders.
The Influence of Negative Beta Assets on the Empirical SML in the Polish Capital Market
Authors: Wolski Rafał
Published: December 2009

The Influence of Negative Beta Assets on the Empirical SML in the Polish Capital Market

The classical approach to the SML assumes that it is a straight line, which means that an investor is willing to accept lower return on the negative beta assets than on the risk-free assets. However, Cloninger, Waller, Bendeck and Revere (2004) challenged this commonly accepted approach. The author of the paper decided to verify the approach using empirical data for years 1999-2006 obtained from the Warsaw Stock Exchange. Finance theoreticians believe that the SML is linear, which means that an investor buying negative beta assets is willing to accept lower return than in the case of a risk-free asset. Cloninger et al. (2004) formulated a hypothesis stating that the SML is V-shaped and that it is not a straight line. It was concluded that an investor had no reason to accept lower return of the negative beta assets; quite the contrary, the investor would expect the same return as on the positive beta ones. The author of this article performed an investigation for the Polish market, taking advantage of companies quoted at the Warsaw Stock Exchange. The investigation demonstrated that between 1999 and 2006, the SML had a V-like shape and thus the research hypothesis formulated in the article was positively verified.
New and Little Known Species of Mites of the Genus Caesarodispus (Acari, Heterostigmata, Microdispidae) Associated with Ants (Hymenoptera, Formicidae) from Ukraine
Authors: Khaustov A.
Published: December 2009

New and Little Known Species of Mites of the GenusCaesarodispus(Acari, Heterostigmata, Microdispidae) Associated with Ants (Hymenoptera, Formicidae) from Ukraine

Mites of the genusCaesarodispusMahunka, 1977 of Ukraine are reviewed.Caesarodispus pusillusKhaustov, sp. n. from nest of antsCrematogaster schmidtiMayr from the Cape Martyan Nature Reserve (Crimea) is described. Type material ofCaesarodispus minutus(Sevastianov, 1981) comb. n. is redescribed.Caesarodispus modestus(Berlese, 1903) collected from antsMessor rufitarsisFabricius is redescribed based on material from Crimea.
On the Migration of Cystacanths Sphaerirostris Picae (Acanthocephala, Centrorhynchidae) in Paratenic host Lacerta Agilis, Histopathology
Authors: Krasnoshchekov G. , Lisitsyna O.
Published: December 2009

On the Migration of CystacanthsSphaerirostris Picae(Acanthocephala, Centrorhynchidae) in Paratenic hostLacerta Agilis, Histopathology

The penetration mechanism ofSphaerirostris picaecystacanths in intestinal wall of the paratenic hostLacerta agilisand characteristic features of inflammatory changes in host intestinal wall are examined. Inflammatory reaction is characterized by predomination of eosinophiles and comparatively small amount of neutrophiles. The reaction is much more pronounced when cystacanth is placed in parallel to the wall of intestine. Extensive edema, plethora, stases in vessels, and slight hemorrhages are observed in submucous membrane. Inflammatory infiltration is less pronounced in case of perpendicular orientation of the proboscis. The secretory glands in cystacanths were not found, secretion on the tegumental surface was not seen, as well as no morphological effect of lytic enzymes on host tissues. The penetration of host intestinal wall is shown to be mechanic, advancement of the cystacanth through the wall of intestine is due to alterations of partial evagination and invagination of the presoma in combination with contractions of the metasoma.
Parazodarion, a New Genus of the Spider Family Zodariidae (Araneae) from Asia
Authors: Ovchinnikov S. , Ahmad B. , Gurko V.
Published: December 2009

Parazodarion, a New Genus of the Spider Family Zodariidae (Araneae) from Asia

ParazodarionOvchinnikov, gen. n. is described. It is a monotypic genus with the type speciesZodarion raddeiSimon, 1889 widespread in Turkmenistan, Southern Kazakhstan, Uzbekistan, Tajikistan, Afghanistan, Iran and Pakistan previously assigned to the genusZodarionWalckenaer, 1826 recently shown to be non-monophyletic.
‘A carnival of crime on our border’: International Law, Imperial Power, and Extradition in Canada, 1865–1883
Authors: Miller Bradley
Published: December 2009

Abstract:

This paper traces the development of Canadian extradition law from the formation of a pro-extradition consensus in the 1860s to the passage of a new Canadian statute in 1877, to that act's final ratification by Britain in 1883. This process of law reform illustrates Britain's continuing legal power in Canada. Throughout the 1870s and 1880s imperial authorities suppressed, delayed, and rewrote dominion extradition law, bringing it back into line with Britain's shifting policy. But the legal ideas that Britain exported to the colonies in this period were not particularly British at all. Rather, what arrived in Canada in the 1870s was an emerging branch of international law heavily influenced by Europe – one that balanced extensive international co-operation against crime with individual civil liberties protections and safeguards for political asylum-seekers. Its origins were in post-revolutionary France, and as it spread to Britain and then the colonies it frustrated Canadian attempts to design a new extradition policy. As a result, this article illustrates the interplay between international law and imperial power in nineteenth-century Canada.
Writing Vice: Hannah Webster Foster and The Coquette
Authors: Harris Jennifer
Published: December 2009

Abstract:

This paper opens with a consideration of the ways women's virtue was judged by their innocence (real or feigned) of worldly vice. For a respectable female author, this creates a quandary: how to write convincingly about a female heroine's supposed sexual wickedness without appearing to possess knowledge of, or insight into, such things. Considering available modes of representing crime (the criminal broadside and execution sermon), the formal constraints and implications of various literary forms (the epistolary novel versus omniscient narration), and the restrictions the real-life narrative imposed, this paper argues that Hannah Webster Foster carefully navigated various literary modes and social conventions in crafting her narrative. The end result is a series of revisions and elisions that protect Foster's reputation, while also rendering the novel far more sympathetic to the heroine.
Wars for Oil:Moby-Dick,Orientalism, and Cold-War Criticism
Authors: Leroux Jean-François
Published: December 2009

Abstract:

Beginning with Edward Said's reflections on the media fall-out post 9/11, the ideological representations of which he likens to the mythical drama enacted in Moby-Dick, the article goes on to revisit the consensus achieved in Cold-War criticism of the novel in light of our awareness of the cultural construction of recent events. Specifically, the article questions the dichotomizing of the novel in terms of East and West and the critical casting of Fedallah and Ahab as scapegoats for collective guilt, drawing on the work of René Girard on the subject. In this way, it confirms the analogical justness of Said's evocation of Moby-Dick in relation to America's “collective imagination” of its relationship to the Near East and argues the book's power to re-orient and subvert that very representation by revealing both its mythical core and the collective acts of violence it seeks to conceal or sanction.
Methodology to Evaluate Quality of Pavement Surface Distress Data Collected by Automated Techniques
Authors: Ong Ghim Ping , Noureldin Samy , Sinha Kumares C.
Published: December 2009

Highway agencies commonly use automated pavement data collection techniques to collect pavement surface distress data at the network level. Although an immense amount of data is collected at the network level, agencies realize that there is a lack of understanding of the quality of the data collected. Traditionally, either the overall pavement condition rating or individual distress ratings are used to evaluate the quality of the condition data. However, each measure has its own pros and cons, rendering the use of a single measure inadequate. This paper presents a set of performance measures that highway agencies can use to quantify the quality of the pavement condition data collected and processed. The set of measures consists of ( a) the pavement condition rating and hypothesis testing for differences, ( b) the percentage cumulative difference in the pavement condition rating over its entire range, and ( c) kappa statistics for individual distresses. This set of performance measures can be used to assess the effectiveness of an automated method for the collection of pavement condition data and the effect of sampling on the pavement condition ratings obtained by automated techniques. The effectiveness of an automated technique is assessed by comparison with the findings of benchmark manual visual surveys. The performance measures offer a complete assessment of the effect of sampling on the overall pavement condition rating, its variation over the entire range, and the identification of individual surface distresses.
Pavement Maintenance Prioritization Using Analytic Hierarchy Process
Authors: Farhan J. , Fwa T. F.
Published: December 2009

The prioritization of maintenance activities is commonly applied in pavement maintenance planning. A widely adopted practice is to express maintenance priority in the form of a priority index, computed by means of an empirical mathematical expression. Though convenient to use, empirical mathematical indices often do not have a clear physical meaning and cannot accurately and effectively convey the priority assessment or intention of highway agencies and engineers. In an attempt to overcome this limitation, this study explores the use of an analytic hierarchy process (AHP) for the prioritization of pavement maintenance activities. The main aim is to identify an approach that can reflect the engineering judgment of highway agencies and engineers more closely. Three forms of AHP are examined, namely, the distributive-mode relative AHP, the ideal-mode relative AHP, and the absolute AHP. The applications of the three methods are illustrated by using an example problem, and the results are compared with the priority assessments obtained by a direct assessment method in which the raters make the evaluation by directly comparing all maintenance activities together. The study concludes that the absolute AHP is suitable for the pavement maintenance prioritization process, on the basis of its ability to provide priority assessments for pavement maintenance activities in good agreement with the priority assessments obtained by the direct assessment method and its operational advantage in evaluating a large number of maintenance activities.
Evaluation of Long-Term Pavement Performance Profile Data for Flexible Pavements
Authors: Corley-Lay Judith , Mastin Jeffery Neil
Published: December 2009

The Long-Term Pavement Performance (LTPP) program has collected longitudinal profile data for a wide variety of pavements nationally for almost 20 years. The program is managed by FHWA, which also maintains the LTPP database. The Office of Highway Policy Information, also of FHWA, increased the frequency with which state agencies must perform longitudinal profile testing for the Highway Performance Monitoring System (HPMS) from biannually to annually. This paper looks at the LTPP program data to see if the increased frequency being required for HPMS is justified. All data sets used in the study were from general pavement studies (GPS) with either aggregate base or asphalt-stabilized base. The international roughness index (IRI) and the time between successful data collections were used to plot IRI versus time for each section. A polynomial equation of the form ax2 + bx + c was fit for each site, and the polynomial was used to calculate the number of years to a 30-point change in IRI by the use of English units of inches per mile. Plots of the change in IRI versus the time between test events by climatic region were also made. As has been reported by others, the largest contribution to the future IRI is the initial IRI. In all climatic zones, the time required to reach a 30-point increase in the IRI decreased with increasing initial roughness. Straight lines fit through the change in IRI versus time between tests had very low slopes that ranged from 0.0052 to 0.0096 point per day. Even at the maximum slope, it takes 3 years to reach a 10-point change in the IRI, using English units. On the basis of the LTPP program data for GPS flexible pavements nationally, annual testing is not warranted.
User-Oriented Model to Support Funding Decisions in Pavement Management
Authors: Mellano Mario , Dell'Orco Mauro , Sassanelli Domenico
Published: December 2009

A new choice model for corrective road maintenance work based on an economic evaluation of users’ expectations and perceptions about road quality is proposed. Because uncertainty affects human subjective perception processes, the model uses fuzzy sets to deal with this kind of uncertainty. Accordingly, the international roughness index was first fuzzified by combining users’ perceptions about pavement conditions with ranges of speeds for four different categories of rural roads. These fuzzy values were then used to calculate vehicle operating costs and freeflow speed. The latter can be considered a function of the international roughness index and the law enforcement factor. To calculate this factor, a fuzzy inference system was set up. Vehicle operating costs and free-flow speed, as well as the value of time, were then used to calculate the travel cost perceived by users. The model finds, through fuzzy maximization of the difference between perceived travel costs before and after interventions, the best allocation of the available budget for a rural road network. In other words, the results suggest the extent of interventions on specific road sections. An application to a real network shows how the proposed model may be used.
Sensitivity of Axle Load Spectra in the Mechanistic–Empirical Pavement Design Guide for Washington State
Authors: Li Jianhua , Pierce Linda M. , Hallenbeck Mark E. , Uhlmeyer Jeff
Published: December 2009

The Guide for Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures [referred to as the Mechanistic–Empirical Pavement Design Guide (MEPDG)] is proposed as an advanced pavement design tool that integrates up-to-date pavement practices. The use of axle load spectra instead of the equivalent single-axle load is a dramatic change. However, the collection of an adequate amount of data over years is required for the accurate characterization of future traffic for design; this gives primary importance to pavement designers having a good understanding of the axle load spectra. This paper presents the typical truck load spectra that satisfy the MEPDG requirements for the Washington State Department of Transportation (WSDOT) and that were developed on the basis of the data collected from selected WSDOT weigh-in-motion stations. Sensitivity analysis was conducted with various typical design parameters of WSDOT flexible pavements. The significant findings are that ( a) one type of axle load spectrum can present load characteristics for WSDOT in MEPDG, ( b) MEPDG is moderately sensitive to the axle load spectra for typical WSDOT pavement designs, and ( c) WSDOT needs to calibrate MEPDG before use. The results have been verified in the calibration of the flexible pavement distress models for WSDOT. It is recommended that agencies that lack data resources test and use the default MEPDG axle load spectral inputs and that the bias may be corrected through model calibration efforts.
Development of a Calibration Procedure for the U.K. Highways Agency Traffic-Speed Deflectometer
Authors: Ferne B. W. , Langdale P. , Round N. , Fairclough R.
Published: December 2009

One of the headline objectives of the U.K. Highways Agency (HA) is to reduce congestion and improve road safety while undertaking necessary highway maintenance. To this end, HA has invested significant resources in developing an appropriate technology to collect road condition and structural data at traffic speeds. This is reflected in the recent procurement for HA of a prototype traffic-speed deflectometer (TSD). The machine, originally developed by Greenwood Engineering A/S of Denmark, exploits the Doppler effect by using lasers to measure pavement deflection velocities under the loaded wheel of a truck. As part of a research program at the U.K. Transport Research Laboratory, the TSD is being developed to undertake structural surveys at traffic speeds. This paper describes the operation of the TSD and continues with a discussion of one of the most challenging aspects of the research program: the development of a calibration procedure. The proposed procedure compares the response of a particular section of road to the TSD, as recorded by an accelerometer embedded in the road pavement, with that recorded by the Doppler lasers on the TSD.
Assessment of Precision of Circular Track Meter and Dynamic Friction Tester
Authors: Jackson N. Mike , Choubane Bouzid , Holzschuher Charles
Published: December 2009

As part of the evaluation of the potential use of the international friction index as the standard for the reporting of friction measurements, the Florida Department of Transportation (FDOT) conducted an assessment of the precision of the dynamic friction tester (DFT) and circular track meter (CTM) test methods. The FDOT CTM equipment and DFT equipment were compared with similar portable equipment owned and operated by the National Center for Asphalt Technology (NCAT) in an attempt to quantify both the repeatability and the reproducibility of the test data obtained. The FDOT portable equipment was mobilized to Auburn, Alabama, for side-by-side testing with the NCAT equipment. This paper summarizes the results of an assessment of the precision of the DFT and CTM equipment on 10 different test surfaces at the NCAT Pavement Test Track. Tests with DFT and CTM were performed at five different locations within each of the 10 different test sections by using both NCAT and FDOT equipment. On the basis of the results of this comparison testing, proposed precision statements are presented for both the repeatability and the reproducibility of the data for the respective pieces of equipment. Correlation relationships are also presented for the portable equipment and the full-scale equipment currently used by FDOT and others.
Top-Down Cracking Predictions for Airfield Rigid Pavements
Authors: Evangelista Francisco , Roesler Jeffery
Published: December 2009

Recent full-scale testing of airfield rigid pavements has demonstrated the possibility of top-down cracking in concrete slabs. The objective of this study was to identify critical gear positions that produced the maximum tensile stress on the top of airfield rigid pavements, given no initial curling. Three individual aircraft gear geometries (dual, dual tandem, and triple dual tandem) and four aircraft types—considering all their main landing gears (B-777, A-380, MD-11, and B-747)—were analyzed for several slab configuration, pavement geometry, and material assumptions. The two-dimensional finite element analysis results showed that consideration of the entire main landing gear of the aircraft was necessary if the top tensile stresses were to be predicted accurately, except for the B-777. The A-380 and MD-11 had the greatest top-to-bottom tensile stress ratios for the full-gear analysis (critical tensile stress at the transverse joint) when the body gears were placed on the same slab for the no-load transfer condition. A factorial analysis further demonstrated that the load transfer efficiency across the joints and the load configuration (single gear or full aircraft) were the most sensitive factors affecting the top tensile stress and top-to-bottom tensile stress ratios.
Estimation of Truck Traffic Inputs for Mechanistic–Empirical Pavement Design in California
Authors: Lu Qing , Zhang Yu , Harvey John T.
Published: December 2009

This study developed default truck traffic inputs for mechanistic–empirical pavement design procedures for the California highway system based on California weigh-in-motion (WIM) data. Both cluster analysis and regression analysis were applied to develop the default axle load spectra. Regression analysis produced unsatisfactory results so it was not used. On the basis of cluster analysis of axle load spectra, the WIM sites were divided into several groups, and default truck traffic inputs were estimated for each group. A decision tree was developed to help designers select the appropriate default factors based on easily available information: geographic location and traffic volume and composition. These data can be obtained from the California Department of Transportation annual report of annual average daily truck traffic. Traffic inputs were developed for both the Caltrans Mechanistic–Empirical Pavement Design and NCHRP Mechanistic–Empirical Pavement Design Guide software.
Calibration of Flexible Pavement in Mechanistic–Empirical Pavement Design Guide for Washington State
Authors: Li Jianhua , Pierce Linda M. , Uhlmeyer Jeff
Published: December 2009

The Mechanistic–Empirical Pavement Design Guide (MEPDG) is proposed as an advanced pavement design tool that integrates up-to-date pavement practices. Since MEPDG was released in 2004, the Washington State Department of Transportation (WSDOT) has continuously worked on calibrating and evaluating the program with regard to implementation for state and local agencies. This paper presents WSDOT's latest efforts on calibrating the flexible pavement portion of MEPDG with data obtained from the Washington State Pavement Management System. It describes preparation of required input data and provides detailed descriptions of input values, as they may apply to states with similar conditions. The calibration process is described, and results and potential implications are discussed. Major observations and general issues encountered in the calibration process are emphasized. An implementation plan is being prepared that may replace the 1993 AASHTO Design Guide with MEPDG in Washington State. This study provides valuable conclusions for national applications: ( a) the flexible pavement distress models were calibrated successfully, ( b) WSDOT flexible pavements require local calibration different from the defaults, and ( c) a software bug does not allow calibration of the roughness model. By making a few improvements and resolving software bugs, MEPDG software can be used as an advanced tool to design flexible pavements and predict future pavement performance.
Quieter Hot-Mix Asphalt Pavements in Washington State
Authors: Pierce Linda M. , Mahoney Joe P. , Muench Steve , Munden Heather J. , Waters Mia , Uhlmeyer Jeff
Published: December 2009

Historically, traffic noise has been reduced through the construction of noise walls and berms, which can be costly (US$2 to $3 million per kilometer in Washington State). Open-graded friction courses (OGFCs) have been found to reduce tire–pavement-related noise. However, OGFC pavement surface lives of less than 10 years, and as short as 4 years, have occurred in Washington State. The primary reason for early failure is surface wear caused by studded tires. In 2006, the Washington State Department of Transportation (WSDOT) placed the first of three test sections (the second test section was placed in 2007 and the third will be placed in 2009) to evaluate noise reduction qualities and pavement performance with the Arizona Department of Transportation (Arizona DOT) asphalt rubber–asphalt concrete friction course, Arizona DOT asphalt concrete friction course modified with styrene–butadiene–styrene, and a standard WSDOT 12.5-mm dense-graded hot-mix asphalt. This paper focuses on pavement surface life and quantifies the reduction and sustainability of tire–pavement-related noise for the project placed in 2006. Initial findings suggest that the OGFC noise reduction benefits quickly diminish as a result of increased surface wear caused by studded tires.
Comparison of Georgia Department of Transportation Design Procedure with Mechanistic–Empirical Pavement Design
Authors: Watson Donald E. , Moore Jason R. , Wu Peter , Jared David
Published: December 2009

This research had several objectives: measure the dynamic modulus of commonly used hot-mix asphalt mix types, two aggregate base courses, and two soils that represent high and low values; compare the results of using measured moduli with Mechanistic–Empirical Pavement Design Guide (MEPDG) Level 3 default moduli for the subgrade and aggregate base material; and compare design results using the AASHTO 1972 Interim Guide for Pavement Design currently being used by the Georgia Department of Transportation (GDOT) with the MEPDG results. The research showed that the MEPDG Level 3 default values for resilient modulus of both soil and aggregate materials are significantly higher than the actual values determined from laboratory test results. Use of actual material properties and load spectra resulted in significantly greater structures being recommended than when Level 3 default values were used for the MEPDG design program. On the basis of these results, GDOT is cautioned against using the default values built into the MEPDG software and should conduct a thorough calibration study using Georgia materials before implementing the MEPDG design procedure.
Methodology to Predict Alligator Fatigue Cracking Distress Based on Asphalt Concrete Dynamic Modulus
Authors: El-Badawy Sherif M. , Jeong Myung Goo , El-Basyouny Mohamed
Published: December 2009

This study focused on integrating the Mechanistic–Empirical Pavement Design Guide (MEPDG) methodology (NCHRP 1-37A and NCHRP 1-40D) with the simple performance test methodology (NCHRP 9-19) to develop a comprehensive bottom-up fatigue cracking distress prediction model based on the dynamic modulus in a methodology that can be implemented in a probabilistic performance-related specification (PRS) methodology for quality assurance (QA) of hot-mix asphalt (HMA) construction (NCHRP 9-22). The main approach for a comprehensive fatigue cracking–damage predictive methodology was to run MEPDG for a large number of simulations using combinations of inputs that were believed significant in classic load-associated bottom-up alligator fatigue cracking and to develop an accurate closed-form solution for the fatigue damage–cracking distress prediction based on the dynamic modulus of HMA. Four major studies have been completed for fatigue cracking prediction methodology: ( a) development of a fatigue damage model based on a two-layer pavement system, ( b) development of an asphalt concrete (AC) effective dynamic modulus model, ( c) development of a predictive methodology to transform a multilayer to a two-layer pavement system, and ( d) validation of the prediction process. The developed methodology approximately but accurately predicts the classic AC alligator fatigue cracking distress that is close to that from MEPDG. Thus, implementation of the methodology into the PRS-based QA system in NCHRP 9-22 is recommended.
Profile Analysis of Arizona Specific Pavement Studies 5 Project
Authors: Karamihas Steven M. , Senn Kevin
Published: December 2009

This paper characterizes the longitudinal profiles of 11 pavement sections within the Arizona Long-Term Pavement Performance Specific Pavement Studies 5 project throughout their service life. The flexible pavements associated with this project were rehabilitated and monitored as part of the study. Road profile measurements were collected on the in-service pavement before rehabilitation and 12 times over the 16 years afterward. Detailed profile analyses of the sections, including calculating roughness values, examining the spatial distribution of roughness, viewing with postprocessing filters, and examining spectral properties are included here. The value of examining performance with the full suite of methods is demonstrated, and these analyses provided a basis for quantifying and explaining the changes in localized roughness and overall roughness with time as well as for linking profile properties to each section's maintenance history and observations of surface distress. The analysis showed that the two test sections with a 2-in. recycled overlay exhibited the largest postrehabilitation increase in roughness. The two test sections with a 5-in. virgin overlay exhibited the smallest postrehabilitation increase in roughness. Much of the increase in roughness on the roughest test sections was caused by narrow dips at transverse cracks.
Opportunistic Behavior in Road Maintenance Markets
Authors: Altamirano Mónica A. , de Jong W. Martin
Published: December 2009

Gaming simulation has frequently proved a valuable method of exploring future scenarios in various fields of policy making. Researchers applied gaming to examine the long-term consequences of contracting out the maintenance of roads. The game, Road Roles, simulates this new situation at an abstract level. Instead of traditional prescriptive contracts, long-term, performance-based contracts are used to cover a whole road network. This new type of contract allows the contractor to decide the location, timing, and type of work to be carried out under the condition that a certain performance level be maintained for a whole network over a number of years. An explanation is given on how the game can contribute to understanding the consequences and presents the results from 14 different sessions held in the Netherlands, Finland, and Spain. Three of the most characteristic and colorful game runs are described in detail. Opportunistic behavior seems to play a substantial role during the tendering and implementation process of road maintenance markets. The role of the road authority and especially its anticipation of contractor behavior, its subtlety in administering specifications, and its incentives for good and bad behavior are key in averting perversities and a decline in road quality. Many agencies, but not all, seem to fail in this important mission.
Life-Cycle Cost Analysis of Surface Retexturing with Shotblasting as an Asphalt Pavement Preservation Tool
Authors: Gransberg Douglas D.
Published: December 2009

This study explored the economics of replacing chip sealing and thin hot-mix asphalt overlays for highways with surface retexturing with the same shotblasting technology that is used on airport pavements. This technology can restore both the microtexture and macrotexture on pavements that have skid resistance due to polishing. An economic analysis of a typical highway lane is conducted to determine life-cycle costs of various options for the hypothetical project. The study uses FHWA pavement life-cycle cost methodology and reports the results on a net present value basis to compare each skid restoration alternative. The analysis is conducted on two levels. First, a traditional deterministic life-cycle cost analysis is completed; and second, a stochastic analysis of life-cycle cost follows, using a Monte Carlo simulation. The conclusion is that shot-blasting is an economically viable alternative to traditional methods for restoring lost skid resistance. Shotblasting also allows achievement of the desired engineering objective without consumption of additional asphalt binder or aggregate, thus making it an environmentally sustainable alternative as well.
Effect of Crack Sealant Material and Reservoir Geometry on Surface Roughness of Bituminous Overlays
Authors: Wilde W. James , Johnson Eddie N.
Published: December 2009

Many state, county, and municipal highway agencies have experienced the formation of bumps when placing single-lift overlays or the first lift of a multiple-lift overlay. These bumps are produced at the location of a previously existing crack, and even then almost exclusively when the crack has been sealed in advance of the overlay. When such bumps are not covered with a subsequent lift, what remains is often a rough ride on a newly overlaid roadway. The effects of crack sealant material type and geometry (shape) of the routed cracks in the existing surface on the formation of bumps in bituminous overlays are described. A matrix of four sealant type treatments and six geometries was designed and implemented in a test section in Jackson County, Minnesota. The overlay on the test section was constructed in September 2007. Results of this investigation indicate that cooler pavement surface temperatures, no over-band, hot-poured crumb rubber, and hot-poured elastic sealants provide the best resistance to the formation of bumps in overlays.
Evaluation of Penetrating Sealers for Reinforced Concrete Bridge Decks
Authors: Mamaghani Iraj H. P. , Moretti C. , Dockter B. A. , Falken L. , Tonnenson J.
Published: December 2009

An evaluation of sealers based on eight sets of laboratory tests was done. Five concrete sealer treatments were studied: D335, DCS, SS, R7, and CT40. These sealers were evaluated for three groups of concrete mixes: normal, fly ash, and old concrete. There were also control specimens that did not use any type of sealer for comparison purposes. The test data were used to determine which sealer and concrete mix combination was the most adequate in improving resistance to the deterioration of concrete properties.
Overview and Comparison of Nationwide Underwater Bridge Inspection Practices
Authors: Strock Thomas , Browne Terence M.
Published: December 2009

The National Bridge Inspection Standards (NBIS) were originally created in 1971 and subsequently updated in 1988 and 2004 (effective 2005). The U.S. Code (23USC151) and the Code of Federal Regulations (23CFR650 Subpart C) outline the national bridge inspection program. FHWA requires that all highway bridges with a submerged substructure be inspected underwater to assess the structural integrity with certainty. Since each state program manager has the responsibility and authority to manage his or her own program under the federal regulations, a variety of local policies, procedures, and techniques are currently employed across the United States, which all comply with the NBIS. An overview is provided of nationwide activities, and underwater inspection techniques and methods used by various states are compared. All underwater inspection techniques and methods are described in detail, with the associated advantages and limitations of each discussed. Also discussed are various state-specific policies on underwater inspector qualifications, underwater inspection intervals, data-gathering techniques, inspection report content, and state policies for non–NBIS-covered structures less than 20 ft long. Historical data on trends for managing underwater inspection programs are reviewed, and future anticipated trends are discussed. Although railway bridges, ferry terminals, and port facilities are not discussed, many underwater inspection techniques and methods are also frequently used on those transportation structures by their maintaining agencies. Data would be informative to all program managers dealing with underwater inspection work.
Bioimprovement of Soils for Highway Applications Using Rolled Erosion Control Products
Authors: Smith Jennifer L. , Bhatia Shobha K.
Published: December 2009

Highway departments are regularly faced with minimizing the soil erosion from highway construction sites. One of the most effective ways of minimizing soil erosion is to provide ground cover that can intercept raindrops. Although bioimprovement (vegetation) is commonly used, it is difficult to establish on steep slopes and in high flow areas, and to a suitable density to provide adequate ground coverage. As a result, rolled erosion control products (RECPs) are often used to provide immediate ground cover protection for soils, enhance the growth of vegetation, and reinforce vegetation once it is established. The success of RECPs has led to development of a wide variety of different RECPs that can vary significantly in basic properties and performance. Although many studies have been published documenting the successful use of RECPs, limited work has been done to compare the rainsplash erosion performance of different types of vegetated RECPs and their mechanisms in minimizing soil erosion. On the basis of results of more than 200 laboratory rainsplash erosion tests on 13 different types of vegetated RECPs, it was found that the use of vegetated RECPs can significantly reduce soil losses on bare soil slopes by an average of 95% to 100% in comparison with bare soil alone. Vegetation improved the performance of the RECPs alone by an average of 54% and 95%. Care must be taken in the design and selection of RECPs to optimize their performance.
Moisture Transport Model for Enhancing FHWA HIPERPAV Predictions
Authors: Xu Qinwu , Ruiz J. Mauricio , Chang George K. , Rasmussen Robert O. , Rozycki Dan K.
Published: December 2009

A portland cement concrete pavement (PCCP) moisture model and associated program are developed for enhancing the FHWA HIPERPAV software predictions. This model predicts PCCP moisture transport and moisture loss to the environment due to drying and self-desiccation. The former is simulated in terms of Fick's second law; the second part is based on Oh and Cha's model. The one-dimensional Crank–Nicolson finite difference method is used to build the mathematical algorithm for solution. FORTRAN coding is developed to program this computational procedure and incorporate the moisture model into the HIPERPAV software. The moisture model has been partially validated with other researchers’ experimental data. Results showed reasonable agreement between predictions and measurements. A sensitivity analysis shows that parameters such as the diffusivity coefficient, surface emissivity, and curing method affect moisture variations, especially at positions close to the surface and the bottom of the slab. Future research will focus on simulations of PCCP critical stresses and distresses with this enhanced moisture model.