bluuebunny/crossref_metadata_2025 huggingface dataset:
Combining Design Patterns and Elements of Social Computing for the Design of User Centered Online Help Systems
Authors: Heckner Markus , Schworm Silke , Wolff Christian
Published: December 2009

Many current (online) help systems fail because users refuse to use them or, even if they do so, they do not perceive them as helpful. There is an obvious gap between the intentions of the help content authors and the achievement of objectives concerning the perceived usefulness by help users. Problems may be divided into psychological and implementation issues. On the psychological side users are often seriously challenged with understanding the instructions given by the system, which usually is not adequately adapted to user's prior knowledge or the vocabulary of a lay person. This problem of expert-lay communication is strengthened by the implementation problem of missing feedback channels. As a result, help systems do often leave users in isolation with their problems. The current article aims to address these issues by presenting an information architecture for an online help system which addresses aspects of communication between authors and users. The approach combines earlier models of design patterns with features for user contribution from social software and design principles in multimedia learning.
Emerging Technology Trends and Ethical Practices for the School Principal
Authors: Garland Virginia E.
Published: December 2009

What is the school principal's role in ensuring ethical technology use while promoting the use of wireless and advanced technologies in instruction? The rapid advances in technology in only the past 5 years, including the increase in laptops and smart phones, have transformed both educational practices and the role of the school principal as technology leader. In this research analysis, social, legal, and moral issues have emerged as three major concerns. Principals must advocate for equity and access to new technologies in their schools, with an awareness of student diversity in race, language, special needs, and gender. By closing the “digital divide” gap, promoting safe internet use policies, adhering to copyright laws, and ensuring environmentally sound procedures, the educational leader can meet the challenges of emerging technology use.
Impacts of Mobile Computing on Student Learning in the University: A Comparison of Course Assessment Data
Authors: Hawkes Mark , Hategekimana Claver
Published: December 2009

This study focuses on the impact of wireless, mobile computing tools on student assessment outcomes. In a campus-wide wireless, mobile computing environment at an upper Midwest university, an empirical analysis is applied to understand the relationship between student performance and Tablet PC use. An experimental/control group comparison of mobile computing enabled learning outcomes in selected courses showed that the integration of wireless technology and highly functional computing tools did not have a negative effect on student assessment results. Out of the four courses evaluated, none of the revealed test scores were statistically different between non-using and mobile computer using groups, indicating no negative impacts of the introduction of ubiquitous technology into the classroom. A freshman-level college math course showed statistically significantly positive differences in course assessment scores when mobile computing was implemented over the same timeline. Results are discussed.
Experimental Study and Artificial Neural Networks Simulation of Activated Carbon Synthesis in Fluidized Bed Reactor
Authors: Hashemipour Hassan , Baroutian Saeid , Jamshidi Esmail , Abazari Alireza
Published: December 2009

In this work, thermal activation of pistachio shell was studied in a fluidized bed reactor. The effects of operating conditions on the pore development within the char particles were studied experimentally. The results showed that activation temperature, residence time, oxidizing gas type and concentration have main effects on the Iodine adsorption capacity of the product. The highest surface area was obtained using steam activation at temperature 850°C for 45 min. The synthesis process was also simulated using artificial neural networks (ANNs) to estimate the Iodine number of the product. The present work applied a Tan-sigmoid transfer function in three layers in the feed forward neural network with back propagation algorithm. The results of the network are in good agreement with the experimental data with a maximum relative deviation of 0.015%.
Characterization of Fluidization and Segregation of Biomass Particles by Combining Image Processing and Pressure Fluctuations Analysis
Authors: Zhang Yong , Jin Baosheng , Zhong Wenqi , Ren Bing , Xiao Rui
Published: December 2009

Bed segregation is inevitable in biomass-sand fluidized beds because of density and size differences, but segregation pattern can be significantly different under various operational conditions. In the present work, the combination of image processing technology and pressure fluctuations analysis is used to investigate the fluidization and segregation. Experiments have been carried out in a 3D fluidized bed. The biomass material studied is cotton stalk. Two groups of binary systems are considered, obtained by mixing sand with biomass particles of different sizes and/or concentrations. In addition, the bed-frozen method is also adopted to examine the segregation degree. It is found that the transition velocity from bubbling to turbulent fluidization regime decreases with the increase of biomass size and concentration. The results also show that the biomass concentration has little influence on the segregation degree, and the biomass size significantly affects the rate of segregation, which increases with the size. The pressure gradient and standard deviation of pressure fluctuation are demonstrated to be useful for indicating the bed segregation, which are validated by the result by the bed-frozen method.
Evaluation of Structural Properties of Cylindrical Packed Beds Using Numerical Simulations and Tomographic Experiments
Authors: Mariani Nestor J , Salvat Wilson I , Campesi Agustina , Barreto Guillermo F , Martínez Osvaldo M
Published: December 2009

This contribution is focused on the analysis of the structure of packed beds of spherical particles at relatively low aspect ratios (i.e., particle to tube diameter ratio) as those arising in multitubular fixed bed reactors. On one hand, the computed tomography (CT) technique is employed to evaluate the position of each particle in the packing and from this information local properties such as particle center distribution and radial porosity profile were obtained. On the other hand, results from a previously developed algorithm to simulate packings were compared with those from our CT data and from literature sources. The agreement was very satisfactory.
Dynamic Kinetic Resolution of Sec-Alcohols in Ionic Liquids/Supercritical Carbon Dioxide Biphasic Systems
Authors: Lozano Pedro , De Diego Teresa , Vaultier Michel , Iborra Jose L
Published: December 2009

Supercritical fluids and ionic liquids are neoteric solvents that can be used as non-conventional reaction media for enzymatic catalysis under optimised conditions. These solvents exhibit many different physical and chemical properties, but have two cross-points: they are not-miscible and can be easily separated from substrates and products, and they can be reused. As supercritical carbon dioxide (scCO2) can dissolve in the ionic liquid (IL) phase (up to 0.7 mole fraction), a new concept of biphasic bioreactors for Fine Chemicals syntheses may be developed by using both enzyme and chemical catalysts "immobilized" into the IL phase, and substrates transported by the scCO2 phase. The system was tested for the continuous chemoenzymatic dynamic kinetic resolution (DKR) of rac-1-phenylethanol in IL/scCO2 by using simultaneously immobilized lipase (Novozym 435) and acid zeolites catalysts at 50°C and 100 bars, providing good yields (up 98.0 %) for R-phenylethyl propionate ester with excellent enantioselectivity (up to 97.3 %), and without any activity loss after 14 days of operation.
The Privacy Paradox: The Case of Secondary Disclosure
Authors: D'Souza Giles , Phelps Joseph E
Published: December 2009

This paper examines the effect of privacy concerns on purchase likelihood. In many consumer-seller relationships, consumers are required to provide personal information to marketers in order to get better service. The law requires that marketer provide a statement of their privacy policies to consumers. Secondary disclosure is a key aspect of privacy policies. Consumers are concerned about giving up privacy, but the impact of such concerns on purchase behavior is unclear. By integrating several marketer-controlled variables like price, product, and channels with a marketers secondary disclosure policy, the study measures the relative importance of the latter along with the effects of secondary disclosure and internet attitudes. The results show that secondary disclosure attitudes influence the weight of secondary disclosure policies in purchase situations. The results also indicate that price sensitivity is influenced by secondary disclosure policies. The clear implications are that privacy concerns do matter and that privacy policies and marketing strategies cannot be set in isolation of each other. The findings are discussed in relation to prior research on privacy and future research directions. Statistical techniques used in the paper include structural equation models, conjoint analysis, and simultaneous equation regression.
Should Banker Pay Be Regulated?
Authors: Kaplan Steven N
Published: December 2009

Pay structures weren't the problem, argues Steven Kaplan, who suggests that contingent equity is a better way to avoid bailouts.
The Effect of Climate on Tree-Ring Chronologies of Native and Nonnative Tree Species Growing Under Homogenous Site Conditions
Authors: Feliksik Edward , Wilczyński Sławomir
Published: December 2009

Dendroclimatic studies were carried out in the experimental stands composed of many tree species situated in the Polish part of the Baltic sea-coast. Increment cores were taken from a 100-years old trees of 2 native species: Norway spruce (Picea abies (L.) Karst.), and Scots pine (Pinus sylvestris L.) and 3 nonnative species: Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), Sitka spruce (Picea sitchensis (Bong.) Carr.) and Silver fir (Abies alba Mill.). Thirty trees of each species were cored. The relationships between the diameter increment and the thermal and pluvial conditions during the period from 1925 to 2005 were analyzed on the basis of standardized tree-ring chronologies and climatic data. It was found that precipitation and temperature of the growing season and months preceding that season affected the annual diameter increment of all investigated tree species. The current year winter and early spring temperatures as well as February and August precipitation had a similar effect on the variation of diameter increment of trees. On the other hand thermal and pluvial conditions of the current year June differentiated the increment rhythm of individual species. A very strong negative effect on diameter growth of trees was observed in the case of winter and early spring frosts. Norway spruce turned out to be a species most resistant to low temperatures. The investigated tree species, especially Norway spruce, was susceptible to water deficiency in the soil during spring and summer. In the case of Scots pine a high precipitation in June stimulated its growth. The diameter increments of Douglas fir, Sitka spruce, Scots pine, and Silver fir were more strongly connected with air temperature than with precipitation. So called all-species chronology of tree-ring width, constructed during this study, permitted to verify the factors having a similar effect on growth response of the investigated tree species. It reflected the mutual characteristics of diameter increments of trees of various species.
Study on the Possible Existence of Water on the Moon
Authors: Robens Erich , Halas Stanislaw
Published: December 2009

Aim of an extensive research project is an analysis of surface properties of Moon's regolith covering and the assessment of the possible existence of usable water on the Moon. In the present paper a short historical survey on Moon's exploration and recent and planned missions is given. Recent recognitions are discussed on the basis of origin and history of the Moon and the import of water from other celestial bodies. Characteristic data and chemical composition of the Moon's surface are summarised with respect to possible water or ice preservation.

Experimental investigations have been made on three typical lunar regolith powder samples from the Apollo 11, 12 and 16 missions. The experiments include spectroscopic and thermal analysis, density measurements and sorptometry. In the present paper we give a survey on measuring methods applied and discuss some results. The measurements confirm results of investigations made with less sensitive equipment shortly after the missions. With regard to water occurrence we found that the regolith cover of the Moon surface is rather hydrophobic and can hardly store water as adsorbed layers.
Chronology of Aeolian Events Recorded in the Karczmiska Dune (Lublin Upland) in the Light of Lithofacial Analysis, 14C and TL Dating
Authors: Fedorowicz Stanisław , Zieliński Paweł
Published: December 2009

The article studies an average-size parabolic dune located in the northern part of the Chodel Basin, Lublin Upland, Poland within the extensive dune field which covers the contact area of the loess patch slope and the high sandy terrace. Its complex structure and the presence of terrace sand and loess in the floor inspired the authors to conduct detailed lithological studies, as well as TL and 14C dating. As a result, it was possible to determine the mechanism and age of aeolian accumulation cycles in the dune, which contains very good representative evidence of aeolian events in the Lublin Upland.
An improved procedure for synthesis of some new 1,3-diaryl-2-propen-1-ones using PEG-400 as a recyclable solvent and their antimicrobial evaluation
Authors: Dawane Bhaskar , Konda Shankaraiah , Shaikh Baseer , Bhosale Raghunath
Published: December 2009

An improved procedure for synthesis of some new 1,3-diaryl-2-propen-1-ones using PEG-400 as a recyclable solvent and their antimicrobial evaluation

A simple and convenient route is described for the synthesis of novel hetero 1,3-diaryl-2-propen-1-ones (chalcones) by using recyclable PEG-400 as an alternative reaction solvent. The reaction is clean with excellent yield, shorter reaction time and reduces the use of volatile organic compounds (VOCs). All the synthesized compounds were evaluated for their antimicrobial activities against several pathogenic representatives.
Identification of Myotis Blythii and M. Myotis (Chiroptera, Vespertilionidae) from Eastern Europe Based on the Measurements of Lower Teeth
Authors: Ghazali M.
Published: December 2009

Identification ofMyotis BlythiiandM. Myotis(Chiroptera, Vespertilionidae) from Eastern Europe Based on the Measurements of Lower Teeth

Since the shape of lower teeth is similar inMyotisspecies, it was the size that was used for differentiation between them. Canonical variates analysis was used to determine the possibility of discrimination betweenM. blythiiTomes, 1857 andM. myotisBorkhausen, 1797 based on lower teeth. The lengths and widths of canines, premolars and molars were measured. More than 89% of the specimens were correctly classified in the models built using measurements of each tooth separately ("one-tooth" models). Better result was obtained for different combinations of the teeth. The largest and the most frequent in the fossils teeth (c inf., p/4, m/1, m/2, and m/3) were chosen for "several-teeth" models. Sets of three teeth maximize the discriminatory power almost to 100%.
Anaerobic capacity of upper extremity muscles of male and female swimmers
Authors: Ogonowska Anna , Hübner-Woźniak Elżbieta , Kosmol Andrzej , Gromisz Wilhelm
Published: December 2009

Anaerobic capacity of upper extremity muscles of male and female swimmers

Study aim: To assess the anaerobic capacity of upper extremity muscles of male and female swimmers by applying two exercise tests.

Material and methods: Male and female swimmers (n = 9 and 6, respectively), aged 19 - 23 years and having training experience of over 10 years, were subjected to two tests: 30-s Wingate for upper extremities and semitethered swimming test. The following variables were determined: body fat content (from 4 skinfolds), maximum power output, heart rate (HR) and lactate (LA) concentration in blood.

Results: Relative power outputs in the Wingate test and swimming force in semi-tethered swimming test (maximum and mean) were significantly (p<0.001) higher in male than in the female swimmers. Maximum LA concentrations were higher in male than in female swimmers, but maximum LA values related to relative power output were in both genders alike. Maximum force produced in the semi-tethered swimming test was strongly (r = 0.765; p<0.001) correlated with maximum relative power output in the Wingate test.

Conclusions: Both tests may be interchangeably applied to determine the anaerobic capacity of upper extremity muscles in swimmers.
Participation in sports and sociometric status of adolescents
Authors: Gadžić Aleksandar , Vučković Igor
Published: December 2009

Participation in sports and sociometric status of adolescents

Study aim: To examine the relationships between sport participation and sociometric status of adolescent youths.

Material and methods: A group of 359 secondary school students from central Serbia (143 male and 216 female) aged 16 - 19 years participated in the study. The subjects were given questionnaires pertaining to their participation in sports and sociometric relations, especially "work with" and "interact with".

Results: In total, about 23% of subjects were actively engaged in sports at various levels: local (11%), regional (8%), national (3%) and international (2 subjects), the others were classified as sedentary. The sport-active subjects scored significantly (p<0.001) higher sociometric acceptance and sociometric status and lower sociometric rejection (p<0.05) than the sedentary ones. However, no significant correlations were found between sport-engagement variables and the sociometric ones.

Conclusions: The presented results can be regarded as preliminary only and call for conducting the study on a larger cohort and to include more psychosocial variables.
The Quebec Clerk Controversy: A Study in Sociability, the Public Sphere, and the Eighteenth-Century Spirit of Enlightenment
Authors: Eamon Michael
Published: December 2009

Abstract:

In December 1790, a proposal advocating the creation of a weekly club for merchant clerks was published in the Quebec Herald, sparking a controversy over the propriety of sociability, public debate, and the proper conduct of youth. This article explores the concerns expressed by contributors to the newspaper, many of whom purported to be of the city's young, ambitious – though little-regarded – clerical class. Over a five-month period, letters arguing the importance of personal and civic betterment and valuing free association, rational discussion, and democratic order came into opposition with missives embodying more traditional fears such as the inherent restlessness, disorder, and impatience of youth. The use of the Quebec Herald to voice these concerns illustrates that a dynamic public sphere of opinion existed in late-eighteenth-century Quebec. Furthermore, the controversy provides a window into the diffusion of the spirit of Enlightenment among the colony's English-language society on the eve of the Constitutional Act.
Class, Gender, and the Social Standard: The Montreal Junior League, 1912–1939
Authors: Chenier Elise
Published: December 2009

Abstract:

This article examines how Anglo-Montreal upper-class women constructed, managed, and maintained their identity and, by extension, their social position by recasting ‘coming out’ as a debutante as training in intelligent philanthropy and civic responsibility. Using the Montreal Junior League as a case study I argue that, though run by and for women, Junior Leagues functioned primarily as a means to confer social status and affirm class privilege. In contrast to their middle-class feminist contemporaries, Junior Leaguers’ sense of their own legitimacy as actors on the public stage derived from their social position as elites, not on their maternal authority as women. By focusing on social status as an identity category, the article concludes that historians need to take more care to treat gender as a primary category of analysis, not the primary category of analysis.
The Spread of Permissive Religion
Authors: Petigny Alan
Published: December 2009

Abstract:

The article takes issue with the received narrative by arguing that, during the 1950s, a secularizing process was underway in the United States. In making this case, the author examines the rise of bingo, Sunday shopping, Billy Graham, and the Revised Standard Version of the Bible.
“It Was My Dream That Screwed Up”: The Relativity of Transcendence inOn the Road
Authors: Haslam Jason
Published: December 2009

Abstract:

This paper interrogates Jack Kerouac's appropriation and transformation of a Thoreauvian-style transcendentalism by reading On the Road through Mikhail Bakhtin's discussion of the chronotope. Kerouac's chronotopic resistance to dominant visions of the United States brings with it a problematic identity politics, specifically in terms of the racialization of the representation of transcendent identity. Rather than a personal or specific failure of a particular author or text, this tension can be read as a portrayal of the inevitable failure of social critiques that are based on notions of finding an “authentic” identity in a transcendence beyond, and disconnected from, historical and personal contexts. In other words, On the Road can be seen as a portrayal of the problems of an American romantic notion of identity, which makes universal claims about the transcendental potential of the individual. On the Road thus points to a difficulty surrounding dominant US notions of the self-reliance of the individual per se.
With Malice toward Quite a Few: Troubled Polities in American Literary Realism
Authors: Varsava Jerry A.
Published: December 2009

Abstract:

Increased scholarly attention is now being paid to the depiction of intercultural relations in American literature across all periods. The books examined in this review article contribute importantly to this body of work, paying particular, though not exclusive, attention to realist fiction of the late nineteenth and early twentieth centuries. As Henry Wonham and Mary Esteve demonstrate, we find embedded within realist literary works sometimes blatantly obvious, sometimes teasingly oblique, representations of racial minorities, women, and immigrants that are most often malicious in intent and inevitably invidious in consequence. Also investigating the depiction of intercultural relations—though focusing on affirmations of cosmopolitanism in American regional literature from 1850 to 1930—Tom Lutz tenders a more sanguine reading of the realist tradition, finding within it reverberations of a democratic sensibility that is, in his view, inalienably American and indeed the very hallmark of American literature.
Application of Improved Crack Prediction Methodology in Florida's Highway Network
Authors: Nasseri Sahand , Gunaratne Manjriker , Yang Jidong , Nazef Abdenour
Published: December 2009

With the growing need to maintain roadway systems despite increasing competition for resources while ensuring safety and comfort for travelers, sound network-level decision making becomes more vital than ever. A stochastic process known as the Markov chain has been used extensively to capture the uncertainty associated with pavement performance over time and to support this critical decision-making process. By application of the Markov chain, this paper investigates the crack histories of flexible pavements to gain insight into the impacts of two primary factors that contribute to the rapid deterioration of surface cracks in flexible pavements: excessive traffic loading and delayed maintenance and rehabilitation. The empirical results of the investigation, obtained by using the data from the Florida Department of Transportation's pavement condition survey database, are presented. The results show that the impacts of the two factors mentioned above are statistically different from one another in terms of the rate of deterioration of Florida's pavements because of cracks. These findings will assist highway authorities in making more timely and efficient network-level decisions.
Impact of Escalating Construction Costs on Long-Term Pavement Performance Loss
Authors: Wang Zhaohua , Tsai Yichang (James) , Pitts Eric , Wu Yiching
Published: December 2009

Escalating construction costs caused by increasing crude oil prices have a serious impact on long-term pavement performance. There is an urgent need for transportation agencies to quantify the impact of the long-term loss of pavement performance (LOPP) and the additional pavement preservation need. This paper proposes a mathematical model that can be used to quantify LOPP. Historical data from the Georgia Department of Transportation (GDOT) from fiscal years (FYs) 1999 to 2007, including pavement survey data and resurfacing expenditures, were used to develop Markovian transition probability matrices. The average annual escalation rate (AAER), 18.1%, was obtained by analyzing the historical resurfacing costs. The impacts of different AAERs (15%, 20%, 30%, and 40%) were analyzed. At GDOT's current funding level, the results show that the composite rating of the non-Interstate pavement network with a 40% AAER would drop to 70 almost 2 years earlier than the one with a 15% AAER. If the AAER is increased from 15% to 30%, the pavement preservation cost needed to meet the expected pavement condition triples from $1.1 billion to $3.4 billion. The LOPP that would occur if there were a sudden increase in construction costs (50%, 100%, and 150%) within a single year was also analyzed. The results showed a 7.8% LOPP for a 100% sudden increase in construction costs in FY 2009. With the impact quantified, it is hoped that transportation agencies can communicate with their state legislatures and stakeholders more transparently about their actual funding needs because of escalating construction costs. Finally, recommendations on improving the accuracy of forecasting are also discussed.
Finite Element Model Analysis of Thermal Stresses of Thick Airport Concrete Pavement Slabs
Authors: Nishizawa Tatsuo , Ozeki Takahito , Katoh Kouji , Matsui Kunihito
Published: December 2009

Thermal stress caused by temperature distribution in pavement slab is important in the structural design of airport concrete pavements. Airport concrete pavement slab is thick; therefore, temperature in the slab varies nonlinearly throughout its depth. Thermal stress caused by nonlinear temperature distribution differs from that of linear temperature distribution. In this study, thermal stress caused by nonlinear temperature distribution was calculated by using temperatures and restraint strains measured in an experimental concrete pavement with 460-mm-thick slabs. The calculated thermal stress differed from curling stress because of the linear temperature distribution. Temperature distributions in concrete slabs of various thicknesses were computed by solving the heat transfer equation with the control volume method. This calculation revealed that temperature distributions in thick concrete slabs were highly nonlinear. Thermal stress was analyzed to compute the nonlinear thermal stress distributions in concrete slabs from the computed temperature distributions by using a three-dimensional finite element model. On the basis of the analysis, effects of slab thickness and nonlinear temperature distribution on thermal stress were discussed. The effect of nonlinearity was found to be pronounced at a slab thickness greater than 300 mm. In this range, the reduction factor for taking into account the effect of nonlinear distribution was larger than 0.7. It was also found that thermal stresses in summer and spring were relatively large.
Design of Tie Bars in Portland Cement Concrete Pavement considering Nonlinear Temperature Variations
Authors: Choi Seongcheol , Won Moon C.
Published: December 2009

Tie bar design at longitudinal construction joints in portland cement concrete pavement is based on the so-called subgrade drag theory. According to this theory, the required maximum spacing between tie bars is inversely proportional to the widths of the lanes that are tied together. As the number of lanes increases to accommodate greater traffic demand, tie bar spacing decreases. In a recent IH-10 project in Houston, Texas, the width of pavement lanes tied together was great enough to require 30-cm (1-ft) tie bar spacing. In Texas Department of Transportation design standards for continuously reinforced concrete pavement, the same spacing is required for both tie bars and transverse steel. The use of 30-cm spacing for both tie bars and transverse steel results in a substantial increase in the cost of the project. The subgrade drag theory assumes uniform temperature distribution through the concrete slab depth and no curling effect is incorporated. This assumption needs reconsideration. Field testing was conducted to investigate slab behavior and to develop more rational designs for tie bars and transverse steel. Concrete displacement gauges were installed at the free edge of the concrete slab to measure transverse horizontal as well as vertical displacements. Steel strain gauges were installed at different locations in tie bars. The concrete slab showed curling behavior; the stresses in tie bars clearly demonstrated the effects of curling. Theoretical analysis was conducted, and the results verified the field data. A new design method was proposed for tie bars.
Development of a Permanent Deformation Model of Asphalt Mixtures for South Korean Pavement Design Guide
Authors: Le Anh Thang , Lee Hyun Jong , Park Hee Mun , Lee Sang Yum
Published: December 2009

The Korean Pavement Design Guide (KPDG) was developed based on a mechanistic–empirical approach. This paper presents the permanent deformation model of asphalt mixtures in the KPDG. The permanent deformation model for various types of asphalt mixtures was developed by using the results of triaxial repeated loading tests. This model was calibrated with the accelerated pavement test (APT) and the Long-Term Pavement Performance (LTPP) database. Through the triaxial repeated loading tests, the permanent deformation model of asphalt mixtures was developed to address the effects of temperature and initial air voids. The model coefficients for the temperature and air voids obtained from the triaxial tests do not need to be calibrated. However, the model coefficients for the shift factor and number of load repetitions should be calibrated with APT data. This study found that the model requires a correction factor to consider the effects of total asphalt concrete (AC) layer thicknesses. The correction factor is useful for simulating the distribution of a real vertical plastic strain for different AC layer thicknesses. A shift factor was found by comparing the measured rut depth from the LTPP sections and predicted values from the KPDG program. A verification study showed that the final permanent deformation model developed in this study can predict the field rut depth of various AC pavements quite accurately.
Effect of Axle Load Spectrum Characteristics on Flexible Pavement Performance
Authors: Haider Syed Waqar , Harichandran Ronald S.
Published: December 2009

The Mechanistic–Empirical Pavement Design Guide (MEPDG) uses performance models to predict cracking and rutting in flexible pavements. A unique mechanism controls the initiation and accumulation of each distress, but each mechanism can have several causes. Axle repetitions and loads are the main causes of all load-related distress types. MEPDG incorporates axle load spectra to characterize axle loading for a site and uses them to calculate pavement response and damage accumulation. These load distributions have a bimodal shape, and a mixture of two continuous distributions can be used to model them. In this paper, closed-form solutions are developed to estimate the characteristics of a mixture of bimodal axle load distributions. The observed axle load spectra from 14 sites in different states were used to relate load distribution characteristics to predicted flexible pavement performance. The overall mean and other characteristics of a bimodal axle load distribution explained the variations in expected flexible pavement performance. Cracking, surface rutting, and ride quality are related to the fourth root of the fourth moment of axle load distributions. Rutting in the hot-mix asphalt layer is strongly associated with the overall mean, but in base and subbase layers it is related to the 95th percentile load of axle load spectra. These findings imply that cracking, rutting, and roughness growth in flexible pavements are caused mainly by axle load distributions having heavier tails with infrequent extreme loads. Heavier loads appear to cause more cracking; a higher number of load repetitions is more critical in developing additional surface rutting in flexible pavements.
Degree of Influence of Active Fillers on Properties of Recycled Mixes with Foamed Asphalt
Authors: Halles Felipe A. , Thenoux Guillermo Z.
Published: December 2009

Active fillers in foamed asphalt mixes are added to modify the fine fraction of aggregate gradation or to reduce the moisture sensitivity of the mix. Some countries use cement as an active filler, and other countries use lime or fly ash, among other ingredients. However, limited information is available concerning the influence of different types of active fillers on the mechanical properties of foamed asphalt mixes. This paper presents the results of a project carried out to study the relative influence of active fillers on the mechanical properties of recycled mixes with foamed asphalt. Four active fillers were studied: portland cement concrete, cement kiln dust, hydrated lime, and fly ash Class C. Indirect tensile strength, triaxial resilient modulus, and triaxial permanent deformation tests were carried out to quantify the influence of these active fillers on the properties of one particular full-depth reclamation material. Different curing methods and moisture conditioning were used to evaluate the role of active fillers after the mix production process. As a result of this study, it was concluded that, for the full-depth reclamation material tested, whereas some active fillers have an important influence on the mechanical properties and long-term performance of foamed asphalt mixes, others act only as mineral fillers of the aggregate gradation. Also, because foamed asphalt takes a long time to cure, some active fillers play an important role in contributing to the early strength of foam recycled mixes.
Culvert Information Management System
Authors: Meegoda Jay N. , Juliano Thomas M. , Tang Chi
Published: December 2009

A pilot scale culvert information management system (CIMS) was developed for the New Jersey Department of Transportation to comply with requirements stipulated by the Governmental Accounting Standards Board, GASB-34, and new federal stormwater regulations. The condition states of culverts are used to express the extent of their deterioration and survival probabilities. A financial analysis model was developed on the basis of the remaining value of culverts and the user cost of failures. Different rehabilitation options were discussed, and recommendations were made for deteriorated culverts on the basis of financial analysis. The pilot CIMS can analyze prescribed culvert information and make decisions to inspect, rehabilitate, or replace culverts or to do nothing at project and network levels. At the project level, this is achieved by comparing inspection, rehabilitation, or replacement costs with risks and costs associated with failure. At the network level, the associated costs are optimized to meet annual maintenance budget allocations by prioritizing culverts needing inspection and rehabilitation or replacement. The CIMS has three major computer software components: databases, user interfaces, and functionality modules. Modules include inlet–outlet structures, culvert segments, culvert assessment, and optimization. Users are able to retrieve culvert and inlet–outlet structure physical and financial information and to generate reports vis-à-vis location, road, and milepost for condition state and assets needing immediate repair. The CIMS will also do the following operations: maintain an up-to-date inventory of eligible infrastructure assets; perform maintenance of eligible infrastructure assets for a given budget using a replicable basis of measurement and measurement scale; and summarize results, noting any factors that may influence trends in the information reported.
Comparison of Methods for Evaluating Pavement Interventions
Authors: Khurshid Muhammad Bilal , Irfan Muhammad , Labi Samuel
Published: December 2009

Decision makers are always faced with the challenge of selecting and implementing cost-effective pavement preservation alternatives, particularly when encountering shrinking budgets and increased competition for funds. Pavement intervention and investment evaluation criteria used in past research and practice are reviewed. The synthesis of pavement preservation effectiveness and efficiency evaluation techniques that is presented is unique from both benefit and cost perspectives. Criteria are of the following categories: effectiveness (benefit) only, cost only, cost-effectiveness, and economic efficiency. Computational details, past applications, merits, and demerits of various evaluation criteria are discussed for each criterion. Then selected criteria are computed with data from a national pavement study; they are used to evaluate alternative rigid pavement rehabilitation treatments. The case study results suggest that the superior short-term effectiveness exhibited by a treatment does not necessarily translate into superior long-term effectiveness. The evaluation results can vary widely for cost only, effectiveness only, and both cost and effectiveness criteria. Thus, evaluation based on cost-only or effectiveness-only criteria can yield biased evaluation results. To be a suitable candidate, a treatment or strategy must be not only effective but also cost-effective and economically efficient and the incorporation of user costs into evaluation can significantly influence the evaluation results. Such a synthesis can be a vital support for highway agencies in decision making for infrastructure management in general and pavement management in particular.
Determining the Service Life of Thin Hot-Mix Asphalt Overlay by Means of Different Performance Indicators
Authors: Irfan Muhammad , Khurshid Muhammad Bilal , Labi Samuel
Published: December 2009

The use of thin hot-mix asphalt (HMA) overlay as a preventive maintenance treatment is gaining wide acceptance in the United States and abroad. Pavement management and maintenance practitioners seek quantitative means to assess the effectiveness of this and other treatments to plan, program, and budget for pavement preservation in the long term. A synthesis was done of studies on thin HMA overlay service life. The service life of thin HMA overlay treatments applied in a midwestern state in 2001 to 2006 is discussed. The study, carried out separately for three functional classes–-Interstates, non-Interstate National Highway System (NHS), and non-NHS–-uses three performance indicators. They are the international roughness index (IRI), pavement condition rating (PCR), and rut depth (RUT). The study finds that the thin HMA treatment service life is 7 to 10 years (basis of IRI), 7 to 11 years (basis of PCR), and 8 to 11 years (basis of RUT). These values are based on the application of the following thresholds: 110 in./mi (IRI), 85 (PCR), and 0.25 in. (RUT), respectively. With the use of the survival model, a probabilistic approach was tested to capture the stochastic nature of the postoverlay deterioration and thus to investigate the variability in the life of that treatment. Furthermore, results suggest that the service life of thin HMA overlays is nonlinearly related to traffic loading and that differences in climatic severity can have a significant impact on the service life of the treatment.
Performance-Based Uniformity Coefficient of Chip Seal Aggregate
Authors: Lee Ju Sang , Kim Y. Richard
Published: December 2009

Development of a new chip seal performance indicator called the performance-based uniformity coefficient (PUC) is presented. The PUC uses the concepts of McLeod's failure criteria for chip seals and the uniformity coefficient used for soil, sand, and aggregate. The aggregate loss performance test, using the third-scale model mobile loading simulator, is used for evaluating the PUC. Results demonstrate that the methodology introduced in this research and McLeod's failure criteria can be excellent tools for narrowing the aggregate specifications required for chip seal construction. In addition to these results, the PUC, which is a gradation-based performance indicator, is an improvement over the previous uniformity coefficient for chip seal construction. The PUC can also aid in aggregate selection for the chip seal, and it can ease and clarify engineering communications within the chip seal industry.
Chip Seal Maintenance
Authors: Lawson William D. , Senadheera Sanjaya
Published: December 2009

This study summarizes the research directed at identifying maintenance solutions for bleeding and flushed pavements surfaced with a chip seal. Factors that contribute to bleeding and flushed chip seals pertain to aggregates, binders, traffic, environment, and construction. No better advice exists for dealing with bleeding and flushed chip seals than to avoid the problem from the outset by employing a preventive maintenance perspective. Bleeding is an immediate maintenance problem that must be addressed; corrective maintenance, or in some cases emergency maintenance, would be done. Basic approaches to treat bleeding include bridging over the live asphalt by applying aggregate of various types and gradations, cooling off the pavement surface by applying water with or without additives, and removing the bleeding asphalt and rebuilding the pavement seal. Flushing, in contrast to bleeding, is typically not a maintenance problem that must be addressed immediately. Basic approaches to treat flushed chip seals are to retexture the existing surface or to add a new textured surface over the flushed pavement. Three promising areas for further research and implementation relative to bleeding and flushing solutions include the uses of lime water, ultrahigh pressure water cutting, and the racked-in seal at intersections.
Preservation Treatment for Wood Bridge Application
Authors: Bigelow Jake , Lebow Stan , Clausen Carol A. , Greimann Lowell , Wipf Terry J.
Published: December 2009

Timber can often be a cost-effective construction material for new bridges. The durability of the bridge greatly depends on proper attention to construction details and fabrication, as well as proper preservative treatment before, during, and after construction. Material repair and replacement costs for bridges are a considerable expense for highway agencies. To address these needs, the objectives of an investigation were to determine the field effectiveness of various treatment alternatives used on Iowa roadway projects and to provide information on preservative treatments, inspection techniques, and current specifications for bridge owners. Special emphasis was placed on providing up-to-date synthesized information for county engineers to maintain their timber bridge inventory more effectively. The project scope included a literature review, identification of testing techniques, on-site inspections of bridges in Iowa, and a review of current specifications and testing procedures. On the basis of information evaluated, these general conclusions were made: copper naphthenate was recommended as the plant-applied preservative treatment for timber bridges, American Wood Protection Association Standards and Best Management Practices should be followed to ensure high-quality treatment of timber materials, and bridge maintenance programs would be enhanced by the development of an effective construction and remedial treatment process to improve bridge durability.
Effects of Environmental Variables on Infrared Imaging of Subsurface Features of Concrete Bridges
Authors: Washer Glenn , Fenwick Richard , Bolleni Naveen , Harper Jennifer
Published: December 2009

Deterioration of concrete due to corrosion of embedded steel reinforcing bars and prestressing strands represents a significant challenge for inspection and maintenance engineers. Delaminations develop in the concrete manifest as spalling, which further exposes the steel to the corrosive environment and accelerates the deterioration process. The typical method for detecting these delaminations is hammer sounding, which requires hands-on access to the material under inspection. Specialized equipment and lane closures are frequently necessary to achieve the required access. Application of infrared imaging to detect the subsurface features in concrete can image such defects from a distance, such that direct access to the surface of the concrete is not required. However, the method relies on environmental conditions to create thermal gradients in the concrete so that these subsurface features can be detected. A study examined the optimum environmental conditions for detection of subsurface features in concrete. The goal was to provide guidance on the practical application of infrared imaging for inspection of concrete bridge components. The effects of solar loading from direct sunlight and wind speed have been examined to determine their impact on the detectability of subsurface features in concrete. The optimum time of day for detection of subsurface defects and the effect of their depth is discussed. Characteristics of optimum inspection conditions for using infrared cameras in the field are described.
Pervious Concrete Pavement
Authors: Henderson Vimy , Tighe Susan L. , Norris Jodi
Published: December 2009

Pervious concrete pavement is an environmentally friendly, sustainable paving material for low-volume, low-speed applications. Pervious concrete has been used in warm climates extensively, but its use in freeze–thaw climates has been limited. The Centre for Pavement and Transportation Technology at the University of Waterloo and the Cement Association of Canada, Portland Cement Association, and local Canadian ready-mix producers have partnered to carry out a Canada-wide study to evaluate the performance of pervious concrete. Three test sections have been constructed to date with more planned for the future. The current test sections are located in southern Ontario and southern British Columbia. They are designed to represent all aspects of pervious concrete including but not limited to materials, design mixtures, structural design, potential applications, fresh and cured properties, permeability, environmental strain, filtration capabilities, and maintenance needs and options. A surface distress evaluation form has been developed with information gathered from two of the test areas as well as a literature review. Two test areas have experienced a winter season and showed minimal surface distresses and maintained permeability. Permeability testing is carried out regularly to track changes as well as to evaluate effects of winter maintenance. Instrumentation has been installed at the test areas to track moisture movement throughout the structure, strain caused by environmental conditions, and the filtering capabilities of pervious concrete. The results of this project will be instrumental in understanding the performance and behavior of pervious concrete in the Canadian climate.