bluuebunny/crossref_metadata_2025 huggingface dataset:
LETTER TO THE EDITOR: The Effects of Nutraceuticals in Patients with or without Chronic Kidney Disease: Classification Matters
Authors: Nikolaidou B. , Katsiki N. , Lazaridis A. , Reklou A. , Grammatiki M. , Doumas M.
Published: November 2013

DEAR EDITOR

We have read with great interest the study by Cicero and
colleagues [1], reporting the long-term effects of lipidlowering
nutraceuticals on Low Density Lipoprotein - Cholesterol
(LDL-C) levels and arterial stiffness. The impressive
reduction of LDL-C combined with the excellent safety profile
points towards further research in this field and calls for
a wider use of nutraceuticals in everyday clinical practice.
Furthermore, the beneficial effects of nutraceuticals in patients
with chronic kidney disease (CKD) are of clinical importance,
since this group of patients is highly susceptible to
atherosclerosis and cardiovascular disease is their primary
cause of death [2-4].

However, a closer look at the demographic data of participating
patients in the Cicero et al. study [1] raises a question:
whether patients included in the non-CKD group were
actually free of renal disease. As depicted in Table 1 [1], the
mean estimated glomerular filtration rate (eGFR) levels in
the non-CKD group were 67.7 ml/min/1.73m2. According to
the 2002 K/DOQI clinical practice guidelines [5] that were
recently updated by the KDIGO 2012 clinical practice guidelines
[6], stage I and II CKD have eGFR levels over 60
ml/min/1.73m2, when other indices of renal damage are present.
Therefore, we would be really grateful to the authors if
they could clarify this issue.

In addition, it would be interesting to know how many
patients had stage I, II, IIIa and IIIb CKD. Moreover, it would be important to know whether nutraceuticals were
equally effective in all stages of CKD, although we acknowledge
that the small number of study participants would
probably not allow for statistical comparisons.

In conclusion, we would like to congratulate the authors
for their interesting study with significant findings, and
thank them in advance for their clarifications.
Normalisation and Stigmatisation of Obesity in UK Newspapers: a Visual Content Analysis
Authors: Patterson Mr. Chris , Hilton Dr. Shona
Published: November 2013

Obesity represents a major and growing global public health concern. The mass media play an important role in
shaping public understandings of health, and obesity attracts much media coverage. This study offers the first content
analysis of photographs illustrating UK newspaper articles about obesity. The researchers studied 119 articles and images
from five major national newspapers. Researchers coded the manifest content of each image and article and used a
graphical scale to estimate the body size of each image subject. Data were analysed with regard to the concepts of the
normalisation and stigmatisation of obesity. Articles’ descriptions of subjects’ body sizes were often found to differ from
coders’ estimates, and subjects described as obese tended to represent the higher values of the obese BMI range, differing
from the distribution of BMI values of obese adults in the UK. Researchers identified a tendency for image subjects
described as overweight or obese to be depicted in stereotypical ways that could reinforce stigma. These findings are
interpreted as illustrations of how newspaper portrayals of obesity may contribute to societal normalisation and the
stigmatisation of obesity, two forces that threaten to harm obese individuals and undermine public health efforts to reverse
trends in obesity.
Detecting wheels
Authors: Diot Emilie , Tavenas Sébastien , Trotignon Nicolas
Published: November 2013

A wheel is a graph made of a cycle of length at least 4 together with a
vertex that has at least three neighbors in the cycle. We prove that the
problem whose instance is a graph G and whose question is "does G contains a
wheel as an induced subgraph" is NP-complete. We also settle the complexity
of several similar problems. [LABEX MILYON (ANR-10-LABX-0070) of Universit?
de Lyon]
An algorithm for solving a capacitated indefinite quadratic transportation problem with enhanced flow
Authors: Gupta Kavita , Arora S.R.
Published: November 2013

The present paper discusses enhanced flow in a capacitated indefinite
quadratic transportation problem. Sometimes, situations arise where either
reserve stocks have to be kept at the supply points say, for emergencies, or
there may be extra demand in the markets. In such situations, the total flow
needs to be controlled or enhanced. In this paper, a special class of
transportation problems is studied, where the total transportation flow is
enhanced to a known specified level. A related indefinite quadratic
transportation problem is formulated, and it is shown that to each basic
feasible solution called corner feasible solution to related transportation
problem, there is a corresponding feasible solution to this enhanced flow
problem. The optimal solution to enhanced flow problem may be obtained from
the optimal solution to the related transportation problem. An algorithm is
presented to solve a capacitated indefinite quadratic transportation problem
with enhanced flow. Numerical illustrations are also included in support of
the theory. Computational software GAMS is also used.
Strong metric dimension: A survey
Authors: Kratica Jozef , Kovacevic-Vujcic Vera , Cangalovic Mirjana , Mladenovic Nenad
Published: November 2013

The strong metric dimension has been a subject of considerable amount of
research in recent years. This survey describes the related development by
bringing together theoretical results and computational approaches, and
places the recent results within their historical and scientific framework.
Tourism policy and territorial imbalances in Spain
Authors: García Fernando Almeida
Published: November 2013

This paper aims to analyse Spanish tourism policy and its relation to a series of facts. The research combines an extensive review of the existing studies into the aspects of tourism policy linked to government, geography and economy with an examination of statistical sources. The main issues and findings analysed in this study are highlighted below. Firstly, the evolution of tourism policy of Spain in the last 60 years in relation to the process of national economic development is analysed. Secondly, a limited role of tourism on economic and territorial balance as well as changes in the regional distribution in the supply of hotel accommodation is highlighted. Thirdly, territorial changes related to the supply of hotel accommodation and GDP per capita are discussed. Finally, certain topics are suggested for future debate: tourism and imbalance as well as tourism and development.
Spatial autocorrelation of communes websites: A case study of the region Stredné Považie in Slovakia
Authors: Klobučník Michal , Bačík Vladimír
Published: November 2013

Since its origination the Internet has been the basic communication channel through which e-Government processes in our society are carried out. The basic element of such processes is an existing website. This paper is the result of long-term research during which the authors collected information on the presence or absence of websites of self-governments in Slovakia. The output can be divided into two main parts. The first one, on the basis of the acquired data, evaluates the overall trend of self-government websites between 2008-2012. The results were distributed in the form of a website devoted to communes of Slovakia, using technology enabling the graphical and cartographic interpretation of the results. In the second part, on the basis of the gathered data, the authors applied spatial autocorrelation, specifically the ‘join count statistics’ method with the subsequent application to selected phenomenon in society, in particular the occurrence of websites of a selected region of Stredné Považie in Slovakia at the same time interval. This way the authors wanted to point out the interaction of communes in the development of websites, whether through inspiration or rivalry among neighbouring communes. From this point of view, mainly in the first period under review (2008), positive spatial autocorrelation is apparent in the occurrence of communes with websites.
Cartographic source materials and cartographic method of research in the past environment analyses
Authors: Nieścioruk Kamil
Published: November 2013

The article reviews a methodology of using early maps and other cartographic materials in the past environment studies. The application of the cartographic method of research is presented on examples from different research fields, but cases from the Earth Science are analysed deeper - from hydrography, through geomorphology to many aspects of economic geography. What is broadly described is a detection of human interaction with the nature: all traces that are marked by settlement, land use, communication, etc. This paper shows that the past environment, with its ways of use and topology can be recreated using early maps. These materials help finding hidden marks from the past, saved in abandoned orchards, old roads composed into modern network, toponyms storing past spatial relations, etc. It is also shown that analyses of early maps have to be conveyed with great care and responsibility, especially when it comes to geometric properties of old cartographic materials. The Geographic Information System (GIS) is helpful in such a situation, but its use is more profound. In this paper GIS is described as a tool being a great step forward in the applications of cartographic method of research and many examples of such applications in the field of a landscape analyses are given - from simple yet informative numeric outcomes of research to 3D virtual creations of long-gone landscapes.
Inflammation as a target of minocycline: special interest in the regulation of inflammasome signaling
Authors: Kauppinen Anu , Salminen Antero , Kaarniranta Kai
Published: November 2013

Minocycline is a wide-spectrum antibiotic derived from tetracycline. In addition to its anti-microbial activity, minocycline is known to possess several immunomodulatory and neuroprotective properties. Fewer severe side effects and more efficient tissue penetration make minocycline better than its parent tetracycline. Doxycycline competes with minocycline in improved biological half-life but minocycline becomes more rapidly absorbed in tissues than doxycycline. Due to its high lipid solubility, minocycline also crosses the blood-brain barrier easily, which increases its relevance in the treatment of diseases beyond the barriers. Inflammasomes are intracellular protein complexes which become primed via NF-kB and MAPK pathways, and activated by various PAMPs and DAMPs. In this article, we hypothese about the capability of minocycline to regulate inflammasomes as part of its anti-inflammatory activity. The hypothesis is based on the ability of minocycline to regulate signals essential to both the priming and the activation of inflammasome signaling
Interior and closure operators on bounded residuated lattices
Authors: Rachůnek Jiří , Svoboda Zdeněk
Published: November 2013

Bounded integral residuated lattices form a large class of algebras containing some classes of algebras behind many valued and fuzzy logics. In the paper we introduce and investigate multiplicative interior and additive closure operators (mi- and ac-operators) generalizing topological interior and closure operators on such algebras. We describe connections between mi- and ac-operators, and for residuated lattices with Glivenko property we give connections between operators on them and on the residuated lattices of their regular elements.
The jump of the Milnor number in the X
9 singularity class
Authors: Brzostowski Szymon , Krasiński Tadeusz
Published: November 2013

The jump of the Milnor number of an isolated singularity f
0 is the minimal non-zero difference between the Milnor numbers of f
0 and one of its deformations (f
s). We prove that for the singularities in the X
9 singularity class their jumps are equal to 2.
Experimental study of the structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se by means of NQR and EPR spectroscopy
Authors: Bolebrukh Olga , Sinyavsky Nikolay , Korneva Irina , Dobosz Bernadeta , Ostafin Michal , Nogaj Boleslaw , Krzyminiewski Ryszard
Published: November 2013

The structure of chalcogenide glassy semiconductors in three-component systems of Ge-As-Se and As-Sb-Se has been studied by means of both NQR (nuclear quadrupole resonance) and EPR (electron paramagnetic resonance) spectroscopy. It is investigated that in the glasses of both systems the value of the electric field gradient at the resonating nuclei grows with increasing concentration of the clusters As2Se3 and Sb2Se3, thereby increasing the NQR resonance frequencies. It appears that for the Ge-As-Se system the structural transition from a two-dimensional to three-dimensional structure occurs at average coordination number $\bar r$ = 2.45. The EPR spectral parameters of glasses depend on the composition, the average coordination number and the temperature, and these are discussed. The effect of ”ageing” for CGS (chalcogenide glassy semiconductors) of As-Sb-Se system due to partial crystallization of the sample is observed from the EPR spectra.
Corrosion and wear study of Ni-P-PTFE-Al2O3 coating: the effect of heat treatment
Authors: Sharma Ankita , Singh A.
Published: November 2013

In the present work, Ni-P-PTFE-Al2O3 nanodispersion coatings were developed on mild steel. These coatings were heat treated and were exposed to 3.5% NaCl solution. Thus obtained as plated, heat treated and exposed coatings were investigated for their corrosion and wear behavior together with other tribological properties. SEM/EDAX and X-ray diffractometry were used to analyze composition and structural changes of the coatings. Corrosion parameters of the coated samples were obtained from electrochemical polarization and immersion tests. Microhardness, wear resistance and friction coefficient of the coatings were also measured. The results showed that heat treatment at 200°C has little effect on the coating whereas treatment at 400°C results in enhanced crystallinity due to formation of intermetallics phases and possibly aluminum phosphide. Beyond this temperature at 600°C coarsening of the grains occurs which reduces the number of hardening sites. These structural changes result in the observance of highest hardness and lowest wear rate in case of coatings treated at 400°C. Corrosion resistance of the coated samples was observed to decrease with the heat treatment presumably due to the various physical and structural changes of the coating components. Similar changes were observed on their exposure to the corrosive media.
On MHD unsteady reactive Couette flow with heat transfer and variable properties
Authors: Makinde Oluwole , Franks Oswald
Published: November 2013

This study is devoted to investigate the effect of magnetic field on a reactive unsteady generalized Couette flow with temperature dependent viscosity and thermal conductivity. It is assumed that conducting incompressible fluid is subjected to an exothermic reaction under Arrhenius kinetics, neglecting the consumption of the material. The model nonlinear differential equations governing the transient momentum and energy balance are obtained and tackled numerically using a semi-discretization finite difference technique coupled with Runge-Kutta Fehlberg integration scheme. Important properties of the velocity and temperature fields including thermal stability conditions are presented graphically and discussed quantitatively.
Applying data envelopment analysis to operating performance in textile industry
Authors: Ho Chia-Hui
Published: November 2013

Operating performance could affect the survival and future development of a business that both businesses and
business managers would devote to the enhancement of operating performance. Having developed for more than
four decades, the consistent upstream, mid-stream and downstream system have been constructed in domestic
textile industry. The output value of textiles in Taiwan has exceeded 480 billion NT dollars, which is not a sunset
industry, as generally described. The impacts of high labour cost, environmental protection measures and changes
of capital market as well as the competition of emerging countries, particularly Mainland China, have made textile
industry in Taiwan face great market competition and pressure. Since textiles are regarded as one of the major
products in Taiwan, the operating performance could affect the survival of the overall industry. In this case, operating
performance survey of textile manufacturers in Taiwan during 2010–2012 is combined with Data Envelopment
Analysis and Slack Variable Analysis to measure the total efficiency, pure technical efficiency and scale efficiency
of top 12 textile manufacturers in Taiwan, tending to provide the reference of operating efficiency improvement for
the manufacturers.

The empirical results show that the overall efficiency in the 3 years appears 0.89 averagely. The relative efficiency
(1) between two manufacturers, Far Eastern New Century and Ruentex Industries, achieves the optimal operating
efficiency, whereas the remaining 10 are comparatively worse. Regarding the analysis of returns to scale, two textile
manufacturers present constant returns to scale, with the optimal operating efficiency, whereas the remaining 10
show increasing returns to scale, revealing that expanding the scale could enhance the marginal return and further
promote the efficiency.
Evaluation of Driver Performance and Distraction during use of in-vehicle Signing Information
Authors: Creaser Janet , Manser Michael
Published: November 2013

The goal of this study was to examine the in-vehicle signing (IVS) function displayed on a mobile device to determine whether drivers’ compliance with speed limits increased when IVS information was present. The study also sought to identify whether any visual distraction occurred while the IVS information was being used. Notifications of speed zone changes along a roadway, of school zones, construction zones, and curves were visually displayed on a mobile device as per project requirements. Sixty participants (balanced for gender) completed the study, which involved performing a simulated drive in one of three conditions along 24 mi of roadways. The three system-on groups represented the following information conditions: IVS plus navigation, navigation only, or IVS only. Each group also completed a baseline (system-off) condition. The driving performance results indicated that drivers complied with most speed zones whether IVS information was present or not; however, average speeds tended to be higher in the system-on conditions. Drivers in the IVS-only condition spent significantly less time looking at the in-vehicle display than drivers who were also presented with navigation information. Response time to a roadside visual detection task was significantly increased only in speed transition zones whether IVS information was present or not. This condition suggests that increased driver workload occurs during transitions to a new speed zone, particularly when drivers are required to search the environment for additional visual information (e.g., signs, pedestrians, other vehicles).
Longitudinal Driving Behavior with Integrated Crash-Warning System
Authors: LeBlanc David J. , Bao Shan , Sayer James R. , Bogard Scott
Published: November 2013

This study created the most extensive set of naturalistic data that has ever been gathered on the following behavior of drivers when interacting with a forward crash-warning system. For the purposes of this paper, data from the naturalistic driving study of the Integrated Vehicle-Based Safety System (IVBSS) program were used. IVBSS data collected from a total of 108 drivers, representing 81,163 steady state following events and 20,096 forward conflict events were extracted and compared. Drivers were from three age groups (younger, middle-aged, and older) and balanced between two gender groups. Three objective measures were used in this study: mean time headway, minimum time to collision, and proportion of time drivers spent in time headway of 1 s or less. Drivers used the research vehicles for 40 days, with the system not activated for the first 12 days and activated for the following 28 days. A linear mixed model was used for the data analysis. Results of this study show that drivers have a tendency to follow more closely when the warning system is activated. It is recommended that a visual display for feedback on real-time safe following distance may help drivers keep a safer distance. This study also observed age-related self-regulation behavior when other vehicles were being followed and showed that older drivers tended to follow farther away from the leading vehicle.
Road Safety Differences between Priority-Controlled Intersections and Right-Hand Priority Intersections
Authors: De Ceunynck Tim , Polders Evelien , Daniels Stijn , Hermans Elke , Brijs Tom , Wets Geert
Published: November 2013

This study analyzes interactions between two vehicles at right-hand priority intersections and priority-controlled intersections and will help to gain a better insight into safety differences between both types of intersections. Data about yielding, looking behavior, drivers’ age and gender, approaching behavior, type of maneuver, order of arrival, and communication between road users are collected by on-site observations. Logistic regression models are built to identify variables that affect the probability that a violation against the priority rules will occur and the probability that a driver will look to the side when entering the intersection. The number of right-of-way violations is significantly higher at the observed right-hand priority intersection (27% of all interactions) than at the priority-controlled intersection (8%). Furthermore, at the right-hand priority intersection, the behavior of drivers on the lower-volume road is more cautious than the behavior of drivers on the higher-volume road, and violations are more likely when the driver from the lower-volume road has priority. This situation indicates that the higher-volume road is considered as an implicit main road. At both intersection types, there is a higher probability of a right-of-way violation when the no-priority vehicle arrives first: this condition indicates that yielding is partly a matter of first come, first served. For both intersections, the way a driver approaches the intersection (i.e., stopping, decelerating, or holding the same speed) is highly relevant for the occurrence of a right-of-way violation and the probability that the driver will look to the sides on his or her approach to the intersection.
Large-Scale Observational Study of Drivers’ Cell Phone Use
Authors: Wenners Keith E. , Knodler Michael A. , Kennedy Jennifer R. , Fitzpatrick Cole D.
Published: November 2013

This report details the 2012 observational study used to determine drivers’ cell phone use in Massachusetts; the study was completed as a component of the annual seat belt observation study by the University of Massachusetts Traffic Safety Research Program. This study identified the magnitude of risky driving behavior throughout Massachusetts. The location, the time of day, and the direction of travel for each observation were determined by random selection with consideration given to the region's fatality rate and length of roadway. Throughout the state, the drivers’ cell phone use at any given daylight hour was determined; the timing allowed for comparisons between different populations. The apparent cell phone use of 17,677 drivers was observed at 145 locations, with a finding of an average cell phone use of 7.0%, a handheld use of 5.6%, and a text messaging use of 1.4%. Females were observed having handheld conversations at a greater rate than males, but there was little difference in text messaging use. Teens were observed text messaging more often than adults and elders, while the handheld conversation rate was similar for teens and adults. Drivers observed wearing seat belts had a lower cell phone use than those who were not wearing seat belts, for text messaging and handheld conversations. Notable variations in cell phone use were identified across various driver demographics, road types, and times of observation and furthered the understanding of drivers’ cell phone use and providing an opportunity for targeted countermeasures.
Investigating Speeding Behavior with Naturalistic Approaches
Authors: Richard Christian , Campbell John L. , Brown James L. , Lichty Monica G. , Chrysler Susan T. , Atkins Randolph
Published: November 2013

Although speeding is a significant contributor to traffic fatalities, attempts to address this problem have not led to a significant reduction in speed-related fatalities. There are a number of inherent shortcomings in using primarily self-report surveys and crash data to learn more about why drivers speed and in selecting countermeasures that will most effectively address speeding behaviors. An emerging empirical approach is to study the speeding choices that drivers make under everyday driving conditions by using naturalistic driving methods. Such an approach has the potential to yield highly informative data about speeding. These data, however, are complicated and prone to analytical confusion and uncertain interpretation if some key conceptual and methodological issues are not addressed. In this paper, an overview is provided of a naturalistic driving study that was intended to (a) identify the reasons why drivers speed; (b) model the relative roles of situational, demographic, and personality factors in predicting travel speeds; (c) classify speeders; and (d) identify interventions, countermeasures, and strategies for reducing speeding behaviors. The focus here is on discussing lessons learned associated with three methodological issues in particular (defining speeding, identifying a way to measure exposure, and obtaining accurate posted speeds) that were crucial to successfully analyzing the data that this study provided and for generating useful results and conclusions. It is believed that careful consideration of these issues will greatly benefit the traffic safety community, especially as future analyses of naturalistic driving data are considered.
Observational Study of use of Cell Phone and Texting among Drivers in California
Authors: Cooper Jill F. , Ragland David R. , Ewald Katrin , Wasserman Lisa , Murphy Christopher J.
Published: November 2013

This methodological report describes survey research and data collection methods used for the second Observational Survey of Cell Phone and Texting Use Among California Drivers study conducted in 2012. This study was conducted by Ewald & Wasserman Research Consultants on behalf of the California Office of Traffic Safety and the Safe Transportation Research and Education Center at the University of California, Berkeley. The goal of the survey was to obtain a statewide statistically representative observational sample of California's cell phone use behaviors, focusing on mobile device use and comparing it with the 2011 survey data. Vehicle drivers were observed at controlled intersections, such as traffic lights and stop signs; a protocol similar to the National Occupancy Protection Use Study methodology published by NHTSA was used. The sample frame included a total of 5,664 vehicle observations from 129 sites. The total percentage of drivers distracted by electronic devices (holding a phone to the ear, manipulating a handheld electronic device while driving, or talking on a handheld device) increased to 6.2% in 2012 from 4.2% in 2011. California's baseline level of cell phone use and driving will be a critical metric over the years as traffic safety stakeholders mobilize to conduct high-visibility enforcement campaigns, explore new policies, expand educational programs, and engineer countermeasures to increase safety on the roads.
Univariate Volatility-Based Models for Improving Quality of Travel Time Reliability Forecasting
Authors: Zhang Yanru , Sun Ranye , Haghani Ali , Zeng Xiaosi
Published: November 2013

The literature is rich in travel time prediction because of its importance in intelligent transportation systems. Despite the proliferation of advanced methodologies, modeling the uncertainty of traffic conditions is still a challenge, especially during congested situations. Travel time reliability associated with its time-dependent variation provides a way to measure the system performance and has received extensive attention in recent years. In practice, one of the measures for travel time reliability is the identification of prediction intervals (PIs). The PI measurement has many potential applications in the development of systems that aim at disseminating real-time traffic information to travelers. From a management point of view, the PIs forecast the unreliable traffic periods and enable the selection of proper strategies to avoid or release possible traffic congestion. The generalized autoregressive conditional heteroscedasticity (GARCH) model has proved to have the ability to model the uncertainties in the literature. However, the model has some drawbacks in traffic forecasting. To improve the quality of travel time reliability forecasting, this paper proposes two univariate volatility models and compares their performance in generating high-quantity PIs. Travel time data collected from automatic vehicle identification stations located along U.S. Highway 290 in Houston, Texas, are used to examine each model's performance in travel time reliability forecasting. Study results indicate that all three models give reasonable PIs that could be used to indicate the variability of future traffic conditions. The statistical analysis and forecasting results indicate that the proposed Glosten–Jagannathan–Runkle GARCH model outperforms the other two models in constructing better PIs.
Business Logo Signing
Authors: Dagnall Erin E. , Katz Bryan J. , Bertola Mary Anne , Shurbutt Jim
Published: November 2013

Specific service signs provide motorists with business identification information along freeway approaches to interchanges. The Manual on Uniform Traffic Control Devices limits the number of these signs along an interchange approach to four and the number of logo panels per sign to six, although there are continuing requests to increase the number of panels allowed per sign. The present research evaluated specific service signs with four, six, or nine panels per sign and with all logo-based panels or all text-based panels. Participants were asked to determine whether a particular business was present on a sign. Mean reaction times indicated that for nine-panel signs, younger drivers took approximately 2.2 s to determine correctly the presence of a business, while older drivers took approximately 2.9 s. In considering drivers of all ages, an increase from six to nine panels brings mean reaction times from 1.8 s to 2.5 s for text signs and from 1.9 s to 2.5 s for logo signs. In a second task, participants were given 2 s to view each sign before reporting the businesses present on the sign. Participants reported three to four businesses on average, regardless of the number of panels on the sign. Considering the generally accepted standard that eye glances away from the forward roadway for greater than 2 s are unsafe, the study concluded that the benefit of providing more service information is presumably not great enough to outweigh the risk of information overload and driver distraction.
Flexible, Mobile Video Camera System and Open Source Video Analysis Software for Road Safety and Behavioral Analysis
Authors: Jackson Stewart , Miranda-Moreno Luis F. , St-Aubin Paul , Saunier Nicolas
Published: November 2013

This paper presents a scalable, discreet, mobile video camera system that takes elevated video data of roadway locations for traffic safety analysis. The video is used to extract microscopic traffic parameters that include road user trajectories, lane changes, and speeds. Collected video data are processed with an open source automatic tracking tool. Trajectories can then be used to analyze road user behavior for specific locations (intersections or highway sections) or to evaluate the safety effectiveness of a treatment. The different elements of the system, including data collection and processing, are discussed. To illustrate the system's versatility, applications (case studies) illustrate the use of the video camera system and open source video-tracking and analysis tool. These studies include video-based analysis of conflict at highway ramps and behavioral analysis of pedestrians and cyclists at signalized intersections that includes red light violations.
Revision and Further Validation of Surface Performance-Graded Specification for Chip Seal Binders
Authors: Vijaykumar Aishwarya , Martin Amy Epps , Arambula Edith
Published: November 2013

The design and selection of chip seal binders for adequate performance in service are currently based on specifications that include tests of emulsion residues or hot-applied asphalt cements at standard temperatures that do not cover the entire range of in-service temperatures, measure properties that are not performance related, and do not consider representative aging conditions for the critical first year. A surface performance-graded (SPG) specification for the evaluation and selection of chip seal binders that addressed these shortcomings was developed as part of previous Texas Department of Transportation (DOT) and NCHRP research projects. In the current study sponsored by the Texas DOT, the SPG specification was revised and further validated. This was accomplished through use of a single emulsion residue recovery method, determination of performance-related properties and exploration of additional criteria, and further validation of the SPG specification thresholds for these properties based on field performance monitoring and a comparison with laboratory results. This study was limited to producing a revised SPG specification for performance-related properties that addressed aggregate retention and bleeding in service. Specifically, the threshold for minimum shear strain at 0.8 G*i was reduced from 25% to 17.5%, and the m-value was removed. The effects of construction and quality control processes were beyond the scope of this study, and additional specifications are needed for use in conjunction with the SPG specification to address these issues and ensure adequate performance.
Low-Temperature Oxidation Kinetics of Asphalt Binders
Authors: Glaser Ronald R. , Schabron John F. , Turner Thomas F. , Planche Jean-Pascal , Salmans Stephen L. , Loveridge Jenny L.
Published: November 2013

A simple dual-mechanism model successfully fits the oxidation of 12 unmodified asphalt binders originating from a wide variety of sources. The kinetic formulation includes fast and slow reaction paths in parallel with free radical interactions between the two reaction pathways. The same Arrhenius parameters are used for all 12 binders studied. The differences in asphalt binder oxidation rates can be explained with the use of only one adjustable parameter, the amount of reactive material available for the fast reaction. This result suggests that unmodified asphalt binders oxidize with essentially the same chemical mechanisms. Because the Arrhenius parameters apply universally, a simple test may be performed to characterize the oxidation kinetics for unmodified binders without expensive, long-term oxidation experiments at multiple temperatures. A rheological study of the materials generated in the aging of the 12 binders using dynamic shear rheometry was also performed to investigate the relationship of rheological changes with chemical changes as binders oxidize. The rheometry consisted of the generation of a series of isothermal frequency sweeps, followed by fitting the resulting master curve with the Christensen–Anderson model. Simple shifting cannot account for the master curve changes, but changes in the model parameters follow a log-linear relationship for oxidation chemical changes. These fits appear to be source dependent, suggesting that a method with two aging time conditions would be required to characterize the rheological property changes in an unmodified asphalt binder as it ages. Such a method would produce a complete master curve–shift function set at any extent of aging, suitable for input into rational performance models.
Recovery and Laboratory Testing of Asphalt Emulsion Residue
Authors: Farrar Michael J. , Salmans Stephen L. , Planche Jean-Pascal
Published: November 2013

This study involves application of two new test methods to the recovery of asphalt emulsion residue, long-term oxidative aging of the residue, and mechanical testing of the unaged and aged residue to determine low- and intermediate-temperature rheological properties. The new methods are the simple aging test (SAT), which is a thin-film (300 μm) oxidative aging test, and a dynamic shear rheometry technique (commonly referred to as 4-mm DSR), which allows testing to −40°C and requires only 25 mg of material. Three polymer-modified emulsions are recovered by two methods: AASHTO PP 72-11 Method B and use of an SAT plate. Both methods use the same evaporative technique to recover the residue (6 h at 60°C in a forced draft oven). The rheological properties (m-value, G* sin d, and ductility) of the recovered emulsion residues by both methods are reported as well as the rheological properties of the aged emulsion using the SAT. The rheological properties of the unaged emulsion residues recovered are roughly equivalent. The proposed SAT recovery method and application of 4-mm DSR offer significant improvements over Method B and current DSR methodology. The recovery process is simpler with the SAT plate than with Method B, and the SAT plate has been designed so that it can be placed directly in a standard pressure aging vessel (PAV) for long-term aging, and the time required for standard PAV aging is reduced from 20 to 8 h. There is no extrapolation of intermediate-temperature DSR data to low temperature. The error from instrument compliance at low temperature is corrected in the 4-mm DSR procedure.
Evolution of the Crossover Modulus with Oxidative Aging
Authors: Farrar Michael J. , Turner Thomas F. , Planche Jean-Pascal , Schabron John F. , Harnsberger P. Michael
Published: November 2013

This study is based on recovered binders from a hot-mix asphalt comparative test site constructed in Arizona in 2001 with mix collected during construction and cores collected in 2005 and 2010. The intent of the study is to evaluate the potential of using the evolution of the binder crossover modulus with time and depth in the pavement to determine the change in linear viscoelastic properties of the binder during the life of the pavement. The crossover modulus is one of three parameters in the Christensen–Anderson (CA) complex shear modulus model. The CA model is used in this study to develop complex modulus and phase angle master curves of the binder as a function of field time, depth, and temperature. The master curves generated demonstrate the change in SHRP specification parameters, such as m-value and creep stiffness, as well as in the mix dynamic modulus with time and depth on the road. In addition, although asphalt dependent, a linear relationship between oxygen uptake and the log of the crossover modulus is reported.
Critical Problems with Using the Asphalt Ductility Test as a Performance Index for Modified Binders
Authors: Tabatabaee Hassan A. , Clopotel Cristian , Arshadi Amir , Bahia Hussain
Published: November 2013

Despite the adaptation of advanced binder rheology characterization methods by many agencies, the asphalt ductility test is still being used in some specifications in the United States and a few other countries as a performance indicator for asphalt modification. In this study, binder properties known to reflect rutting and fatigue resistance were examined in a set of binders modified with two types of commonly used elastomeric polymer modifiers. The results showed no correlations with binder ductility. Additionally, a test procedure was developed by using a dynamic shear rheometer (DSR) as a surrogate to the conventional ductility test, results of which showed that both elastomeric modified binders are much more ductile than conventional binders, even when conventional ductility showed a loss of ductility. Finite element modeling was used to show the significant effects of decreasing true strain rates with elongation on the sample's stress and strain state attributable to the constant crosshead speed in the conventional ductility test. Because of the well-known dependency of failure stress and strain of viscoelastic material on strain rate and temperature, comparing binders with varying ductility values measured in the conventional test is essentially flawed because it is equivalent to comparing them at different temperatures and is thus fundamentally unreliable as an indicator of the asphalt's performance in the pavement. It is therefore strongly recommended that the practice of using low-temperature conventional ductility be removed from modified binder specifications, or the DSR procedure proposed in this paper be used to evaluate modified asphalts as a preferable test method.
Mechanism of Crumb Rubber Modifier Dissolution into Asphalt Matrix and Its Effect on Final Physical Properties of Crumb Rubber–Modified Binder
Authors: Ghavibazoo Amir , Abdelrahman Magdy , Ragab Mohyeldin
Published: November 2013

Modification of asphalt by crumb rubber modifier (CRM) is mostly done through exchange of components between asphalt and CRM. At 160°C and 10 Hz, CRM absorbs aromatics of asphalt and swells; however, at 220°C and 50 Hz, CRM dissolves into the asphalt; this process leads to the release of different components of CRM including carbon black, fillers, and polymeric and oily components. Depending on interaction conditions, CRM dissolution is performed differently, and therefore the state and role of the released components can be different. In this research different mechanisms of dissolution of one size of CRM in asphalt matrix and their effects on property development of modified asphalt were studied by using different analytic techniques, including dissolution test, dynamic shear rheometer (DSR), thermogravimetric analysis (TGA), and Fourier transform infrared (FTIR) spectroscopy. Dissolution test results in combination with DSR results indicate the state and the role of CRM particles in the matrix, while TGA and FTIR spectroscopy show the type and amount of released components from CRM. The results reveal that for the materials used in this study interaction temperature is the main factor affecting the mechanism of dissolution of the CRM particles and consequently defines the role of the released components of CRM in asphalt matrix. DSR results indicate that during interactions at 190°C (intermediate interaction temperature), released components are more effective on physical properties of asphalt than are released components during interactions at 220°C (high interaction temperature).
Evaluation of Low-Temperature Properties of Asphalt Binders and Mixtures
Authors: Premkumar Laxmikanth , Chehab Ghassan , Solaimanian Mansour
Published: November 2013

Because of the widespread use of modifiers and additives in asphalt bitumen, this study revisits and evaluates the adaptation of the time–temperature superposition principle that is incorporated into the low-temperature Superpave® binder specifications. The study builds on results of bending beam rheometer (BBR) tests conducted on samples of asphalt binders used in seven different surface layer mixtures. Both 240-s and 2-h BBR tests were conducted at three different temperatures: the low temperature of the asphalt performance grade (TL), 10°C higher than the low-temperature grade (TL+10), and at −5°C to construct the flexural creep stiffness master curves. Additionally, indirect tensile tests were conducted on the surface layer mixtures to determine the low-temperature properties. The BBR test results show that the methodology adopted in using the equivalence principle to formulate the low-temperature Superpave binder specifications does not accurately apply for some of the binders used in this study. Thus, modifications to the specifications for loading times and test temperatures are suggested. Further, the time–temperature shift factors for the binders evaluated are compared with the universal shift factors used in the SHRP study. The observed mismatch in the shift factor sets is in disagreement with the implicit assumption that all asphalt binders can be characterized by similar shift factors at low temperatures. The shift factors of the binders and mixtures used in this study tend to match well, particularly at high testing temperatures.
Analysis of Five-Point Bending Test for Multilayer Surfacing System on Orthotropic Steel Bridges
Authors: Li J. , Liu X. , Scarpas A. , Tzimiris G. , Kasbergen C. , Hofman R. , Voskuilen J.
Published: November 2013

The French five-point bending (5PB) test provides a laboratory-scale test that allows studying the fatigue resistance of surfacing systems on orthotropic steel deck (OSD) bridges. The surfacing structure for OSD bridges in the Netherlands is mostly a multilayer system: top porous asphalt (PA) layer, guss asphalt (GA) layer, steel deck, and two membrane layers. In this paper, an analytical solution for the 5PB test setup is presented first. To understand better the influence of geometrical, mechanical, and structural parameters on the performance of the typical multilayer surfacing system of OSD bridges in the Netherlands, the 5PB test specimens with five structural layers have been investigated. The parametric study was performed at the numerical platform CAPA-3D, which was developed at the Section of Structural Mechanics of the Delft University of Technology. The thicknesses of the top PA layer, middle GA layer, and the steel plate were varied. The influences of the mechanical properties of both top and bottom membrane layers were studied. The sensitivities of those influence factors were evaluated by examination of the maximum tensile stress at the top surface of the PA layers and the strain distributions through the entire thickness of the specimen at two cross sections.
Experimental Evaluation of Shear Resistance of Improved Steel–Asphalt Interfaces
Authors: Bocci Edoardo , Canestrari Francesco
Published: November 2013

Although steel orthotropic deck is currently the most widely adopted solution for long-span bridges, the poor adhesion to the upper asphalt layers still represents a serious problem without a clear solution. In recent decades many techniques that involve the use of special bituminous bonding coats, reinforced asphalt membranes, net-reinforced steel deck surfaces, or epoxy asphalt binders have been applied, with varying results, to improve the level of adhesion of the asphalt pavement to the steel surface. In this experimental study, two such techniques were adopted to investigate the shear resistance of steel–asphalt pavement systems. The first technique used epoxy asphalt both as a bonding coat and as a binder of the upper asphalt layer, while the second technique involved the use of a reinforced asphalt membrane that was applied on the steel deck before overlaying with conventional hot-mix asphalt (HMA). The Ancona Shear Testing Research and Analysis shear test device was used to evaluate the shear resistance of different types of HMA–steel interfaces and to investigate the effects of temperature and normal stress. The results have been compared with the shear properties of bitumen-coated interfaces, studied in previous research. The results showed that epoxy asphalt guaranteed high performance regardless of the test temperature. However, the shear resistance of the system with the asphalt membrane was lower than with the epoxy asphalt, although it was higher than the resistance of bitumen-coated interfaces at high temperatures.