bluuebunny/crossref_metadata_2025 huggingface dataset:
African American Identity and a Theory for Primary Cultural Instructional Design
Authors: Thomas Michael K. , Columbus Marco A.
Published: December 2009

This article is on the strange confluence of culture, identity, learning, and systemic design. We argue that the work of instructional design is, essentially, work on culture and identity. A person's culture and identity fully and inextricably situate their thought, action, and interaction. For this reason, this inherent situatedness of culture and identity must be explored by those who endeavor to do instructional design work. Instructional designers must be able to navigate the complex and treacherous waters of culture and identity in order to create effective and appropriate designs for learning. Here we take on the particular case of African American learners. We argue for the empirically verifiable existence of three identity types of African Americans and we suggest that design work should target learners displaying one of these identity types, referred to here as primary cultural. In this way, this article may be seen as exploring the problem of constructing theory on primary cultural instructional design. We first explore culture, then identity, and then the interaction between culture and identity. We then move to our study and how it informs our understanding of cultural identification and academic identity and then we conclude with the implications for design research.

It is a peculiar sensation, this double consciousness, this sense of always looking at one's self through the eyes of others, of measuring one's soul by the tape of a world that looks on in amused contempt and pity. One ever feels his two-ness, – an American, a Negro; two souls, two thoughts, two unreconciled strivings; two warring ideals in one dark body, whose dogged strength alone keeps it from being torn asunder.
A Simulation Model of Combined Biogas, Bioethanol and Protein Fodder Co-Production in Organic Farming
Authors: Oleskowicz-Popiel Piotr , Thomsen Mette Hedegaard , Thomsen Anne Belinda , Ejbye Schmidt Jens
Published: November 2009

In order to evaluate new strategies for the production of renewable energy within sustainable organic agriculture, a process-simulation model for a 100 ha organic farm was developed. Data used for the model was obtained from laboratory trials, literature data, consultancy with experts, and results from the BioConcens project (http://www.bioconcens.elr.dk). Different design approaches were evaluated in order to establish the most suitable configuration. Rye grains, clover grass silage, maize silage, whey and cattle manure were selected as raw materials for co-production of fuels, feed and fertilizer at the organic farm, based on the fact that crops grown in organic agriculture act as key carbon sources whereas manure and whey were applied primarily as the nutrient and water supply for the fermentations within the process (anaerobic digestion and simultaneous saccharification and fermentation, respectively). Results from batch and lab-scale fermentation trials provided basic input for the model. To cover the direct energy requirements on the farm, it was calculated that it requires approximately 16.2 ha of rye and 14 milking cows or 5.7 ha of clover grass, 2.5 ha of maize and 13 cows to supply a 100 ha organic farm with ethanol or biogas, respectively. This calculation was based on the assumption that the electrical efficiency of CHP (combined heat and power) unit was 38%. A variety of different scenarios can be simulated to mirror the farmer's needs.
Transdermal Drug Delivery by Microneedles: Does Skin Metabolism Matter?
Authors: Al-Qallaf Barrak , Mori Daisuke , Olatunji Lola , Das Diganta Bhusan , Cui Zhanfeng
Published: November 2009

Microneedle arrays have been shown to increase skin permeability for the transdermal delivery of drugs with high molecular weights. Various theoretical studies have been proposed to predict the drug transport behaviour after drug injection using microneedles. However it is important for the optimal design of microneedle systems to consider the effects of biological factors such as skin metabolism and variations in pharmacokinetic parameters as well as to improve the enhancement of skin permeability. A mathematical model for microneedle systems is introduced and applied to simulate the verapamil transport with metabolism in the skin. A comparative analysis for a transdermal delivery of verapamil from microneedles is presented in this paper. The results indicate that the skin metabolism does not markedly affect the skin permeation after verapamil injection using microneedles.
Gravity Packing of Same Size Spheres and Investigation of Wall Ordering
Authors: Sahu Kisor Kumar
Published: November 2009

In the first part of the present study, Discrete Element Method (DEM) is adopted as a numerical simulation technique for studying gravity packing of randomly distributed monodispersed particles in a box of a rectangular cross section (can be thought as a fluidized bed). Packing density, coordination number distribution and radial distribution function (RDF) are calculated. Stability of the packing, spatial and temporal effects of the wall on packings are analyzed. Qualitatively and quantitatively, the results agree well with the existing literatures. Since this model uses structural reconstruction, many of the features of random packing like clear second peak split in the RDF plot have been observed. From experiments, it is well known that the confining walls impart some order in the near-wall regions. However to the best of the author's knowledge, the actual symmetries of these orderings (of walls) have never been analyzed and these have been the focus of the second part of this study. Taking a cue from structural analysis of amorphous (glassy) atomic systems, the Honeycutt-Andersen (HA) index and Bond Order Orientation (BOO) order have been employed to study the local symmetries of both near wall and core regions. It shows that the 1551 HA index, signifying icosahedral order, is more predominate in the core part than the wall. There is also some good amount of cubic symmetries both in the wall and core regions. However the most predominate structure is distorted icosahedra, which is probably appearing because of a competing effect between the icosahedral order and cubic symmetries.
Bioenergy II: Production of Biodegradable Lubricant from Jatropha curcas and Trimethylolpropane
Authors: Mohd. Ghazi Tinia I. , Gunam Resul Mohamad F. M. , Idris Azni
Published: November 2009

Jatropha oil has good potential as the renewable energy as well as lubricant feedstock. Production of Jatropha oil based lubricant was performed via a two-step process; (i) the transesterification of Jatropha oil to produce Jatropha Methyl Ester (JME) and, (ii) transesterification of JME with trimethylolpropane (TMP) under the presence of alkaline based catalyst. Transesterification of Jatropha oil was carried out at 65°C for 1 hour by using 1-2% NaOH as catalyst. While, the transesterification of JME was carried out at 150°C with pressure kept at 10mbar. The conversion of JME to jatropha biolubricant was found to be more than 80%. However, to maintain forward reaction, the amount of JME was maintained at about 4:1 ratios to TMP. The basic properties of jatropha biolubricant are found comparable to other plant based biolubricant.
Heat Transfer and Pressure Drop Studies in a Circular Tube Fitted with Straight Half-Twist Inserts
Authors: Siva Rama Krishna V , Pathipakka Govardhan , Sivashanmugam Palani
Published: November 2009

Experimental investigation of heat transfer characteristics of circular tube fitted with straight half twist insert has been presented. The heat transfer coefficient increases with Reynolds number and decreases with spacer distance for both the single direction and left-right twist inserts. Also, there is no appreciable increase in heat transfer enhancement in straight half twist insert with 2-inch spacer distance. Experiments were carried out in turbulent flow using straight half twist insert with 4-inch spacer and similar trend of increasing Nusselt number with Reynolds number was observed. CFD simulation for the heat transfer augmentation in the plain tube and the tube fitted with half twist inserts has also been explained using Fluent version 6.3.26. The data obtained by simulation are matching with the experimental value with the discrepancy of less than ±10% for the plain tube and the tube fitted with straight-half twist inserts for Nusselt number and friction factor.
CFD Comparative Investigation of the Performances of Reverse Flow and Uni-Flow Hydrocyclones in the Enrichment of the Phosphate Pulp
Authors: Mokni Ines , Dhaouadi Hatem , Mhiri Hatem , Bournot Philippe
Published: November 2009

This paper presents a CFD comparative investigation of two types of hydrocyclone: uni-flow and reverse flow hydrocyclones. The study is conducted by means of a Reynolds Averaged Navier-Stockes (RANS) simulation using the finite volume code Fluent. The fluid flow is described by the use of the Reynolds Stress Model, while the determination of particles flow and the air core formation are modeled by the mean of two multiphase models which are respectively the Stochastic Lagrangian model (DPM) and the Volume of Fluid Model (VOF). The flow features are examined in terms of pressure drop and separation efficiency in order to contribute to better performance. The validity of the proposed approach is verified by the good agreement between the predicted and the measured results which are given by the Company of Phosphate of Gafsa (CPG-Tunisia). This study proves that uniflow hydrocyclone is more energy efficient because of its lower pressure drop and its higher removal efficiency for small particles from their carrying fluid.
Contingent impression management in sexual disclosure by older adolescents corresponding in cyberspace: The role of gender dyads
Authors: Wan Chin-Sheng , Chung Su-Hsiang , Chiou Wen-Bin
Published: November 2009

The aim of this research was to investigate whether adolescents' willingness to correspond with cyber friends who had disclosed information about their own sexuality differed by the gender composition of correspondent and discloser dyads. The study involved 192 Taiwanese late adolescents,
all of whom reported having had sexual self-disclosure experiences in cyberspace. When males received sexual disclosure from male correspondents and females received sexual disclosure from female correspondents, they were more likely to exchange information as the topics increased in intimacy,
revealing a reciprocal strategy in impression management. Regardless of the intimacy of the topic, males showed a high level of willingness to correspond with a female discloser, revealing a liberal strategy of impression management. In contrast, females were less willing to correspond with
male disclosers, revealing a conservative strategy of impression management.
Revisiting the scale of the Moral Entrepreneurial Personality in China
Authors: Miao Qing
Published: November 2009

Moral entrepreneurs have been defined as activists who devote considerable time to influencing people to change their values to a particular value system (Becker, 1963; Posner, 1999). Yurtsever (2003) built a measurement model of the moral personality of entrepreneurs,
called the Moral Entrepreneur's Personality (MEP) through an intensive study of members of two nonprofit organizations as well as students, professors, and staff members from two universities. Creating Public Awareness, Resistance, Anticipating Threats, and Mobilizing Power have been identified
as the four dimension components of the MEP.In the present study the aim was to examine the generalizability of the MEP measurement model in a Chinese context through a large-scale survey of top managers of Chinese corporations.
Second language learning success and motivation
Authors: Engin Ali Osman
Published: November 2009

The aim of this study was to understand the importance of the types of motivation students need to learn a foreign language successfully. Teaching and learning a foreign language are dependent upon positive motivation. A questionnaire and an achievement test were prepared and administered
to a group of 44 students. Results were analyzed and evaluations and comparisons between success and motivation levels were then used to make suggestions for planning activities relating to teaching and learning languages.
Susceptibility to interpersonal influence: A study in Turkey
Authors: Ebren Figen
Published: November 2009

In this paper the Susceptibility to Interpersonal Influence (SUSCEP) Scale (Bearden, Netemeyer, & Teel, 1989) dimensionality in Turkey is explored. Susceptibility to interpersonal influence is a general trait that varies across individuals for which a person's relative influenceability
in one situation tends to have a significant positive relationship to his or her influenceability generally. A survey of 268 university students in Antalya, Turkey was conducted using the structured questionnaire of the SUSCEP. Susceptibility to interpersonal influence has been conceptualized
as being either informational or normative. The factor analysis of the data consistently revealed a two-factor correlated structure. A comparison of normative and informational scores based on individualistic/collectivistic culture was also made.
Automatic thoughts as predictors of Turkish university students' state anxiety
Authors: Aydin Kâmile Bahar
Published: November 2009

The aim of the study was to examine the correlation between automatic thoughts and state anxiety. A total of 220 (119 females, 101 males) fourth-year students at Mehmet Akif Ersoy University, Turkey, completed the State-Trait Anxiety Inventory (STAI; Spielberger, Gorsuch, & Lushene,
1980) and the Automatic Thoughts Questionnaire (ATQ; Hollon & Kendall, 1980) when they were preparing for their final examinations. The predictor variable of the study was automatic (negative, dysfunctional) thoughts, while the predicted variable was state anxiety. Simple linear regression
analysis was used to examine the data. Consistent with the researchers' expectations, automatic thoughts were a significant predictor of state anxiety. State anxiety explained 39% of the total variance in relation to students' automatic thoughts. Findings are discussed in the light of possible
developments at Turkish universities to train students to overcome these thought patterns and the resultant anxiety.
Jordanian parental efficacy about the reduction of adolescent behavior problems
Authors: Simadi Fayez A. , Olimat Hmoud , Momani Fawwaz
Published: November 2009

Parenting beliefs about efficacy in the prevention of adolescent problem behaviors in Jordan in terms of some sociodemographic factors are examined in this study. A group of 171 parents to adolescent children was randomly selected from several areas in northern Jordan. ANOVAs were used
to examine the role of sociodemographic variables in explaining parents' beliefs about their efficacy in preventing such problems. Predictor variables included parents' educational attainment, family income, place of living, occupation, and gender. Results revealed a significant impact in
the fields of educational attainment, gender, and family place of living on the parents' belief in their efficacy, while occupation and family income were less significant.
Predicting stress in male and female psychiatric patients and healthy volunteers
Authors: Zöller Madeleine , Archer Trevor
Published: November 2009

The present study was aimed at examining the relationships between affective status, mood, and stress in both a psychiatric patient group (n = 100) and a healthy volunteer group (n = 101 persons), as well as trying to find evidence of a gender effect. The Positive Affect
(PA) and Negative Affect (NA), Stress and Energy (SE), Dispositional optimism (LOT), Comprehensive Psychopathological Rating Scale (CPRS) self-rating scale and the DSM-IV and ICD-10 Personality Questionnaire (DIP-Q) were used. Psychiatric disability had a detrimental effect on stress, energy,
and optimism. The results indicated that stress was predicted by NA and that PA was counterpredictive for stress. Different effects were found for males and females, with NA predicting stress for both men and women, while the DIP-Q general criteria were stress predictors for males only and
PA was counterpredictive for stress in men. Stress as a dependent variable was not significantly predicted by either DIP-Q general criteria, CPRS-depression, CPRS-compulsion, or CPRS-anxiety. It was predicted by negative affect and counterpredicted by positive affect. Data suggest that negative
affect was the most important factor in predicting stress. The healthy volunteer group was found to be less affected by stress than the psychiatric patient group.
School satisfaction among Chinese mainland adolescents
Authors: Tian Li li , Gilman Rich
Published: November 2009

The major goals in this exploratory study were to investigate the absolute levels of school satisfaction, and clarify the relationship between school satisfaction and gender/grade among Chinese mainland adolescents. Participants were 1,339 middle school students from grades 7, 8, 10,
and 11 who completed the Adolescents' School Satisfaction Scale, a subscale of the Adolescents' School Well-being Scale (Tian, 2008). Results show that the highest school satisfaction domains are peer relationship and teacher-student relationship and that male and female students and students
from different grades report different levels of school satisfaction. Implications for future research and educational practices are discussed.
Personality implications of adaption-innovation: IV. cognitive style as a predictor of marital success
Authors: Skinner Nicholas F. , Iaboni Kristine N.
Published: November 2009

The present study provides support for the hypothesis that similarities and differences in cognitive style could mediate the success of a marital relationship. Forty-five married couples, whose scores on the Marital Views Survey indicated they were satisfied in their marriage, independently
completed the Kirton Adaption-Innovation Inventory (KAI; Kirton, 1976) to determine their cognitive style (adaptor or innovator). Both members of 45 divorced couples also completed the KAI. Significantly more adaptor/adaptor dyads (32/45, i.e., 71%) were found among married couples than in
the divorced sample, suggesting that the preference for structure characteristic of spouses in adaptor/adaptor pairings enables them to produce mutually beneficial approaches to change and solutions to problems in their marriages. The KAI may be valuable in the prospective determination of
marital compatibility, and in therapy protocols for couples with marital difficulties.
English language learning and teaching styles in two Turkish primary schools
Authors: Egel Ilknur Pekkanli
Published: November 2009

Foreign language learning styles are aimed at facilitating students' learning and therefore the teaching style used is important in terms of matching learners' styles to their educational needs. The present study was aimed at investigating several dimensions of primary school students'
language learning styles and the ways in which certain styles are shaped and favored by teachers' teaching styles. The primary aim was to find out whether or not the measures taken by the Turkish Ministry of Education regarding rectifying the shortage of teachers of English as a foreign language
have had an effect on the learning styles of primary school students. The secondary aim was to examine the varying learning styles of EFL students in two primary schools and to establish whether or not there has been a change in these learning styles. Finally, the researcher examined whether
or not the economic conditions of the schools had an influence on the students' learning styles.
The influence of transformational leadership on workplace relationships and job performance
Authors: Li Chung-Kai , Hung Chia-Hung
Published: November 2009

Social-identity and social-exchange theory are employed to examine the role of leader-member relationships (LMX) and coworker relationships (CWR) in explaining the relationship between transformational leadership and task performance/organizational citizenship behavior. These relationships
remain unclear in the current organizational literature. Survey data were collected from 1,040 teachers in 52 elementary schools in Taiwan. Results indicate that all 4 dimensions of transformational leadership have positive effects on LMX, whereas only individualized consideration and inspirational
motivation positively affect CWR. It was also found that LMX is a more efficacious predictor of task performance than is CWR, whereas CWR, rather than LMX, is the better predictor of organizational citizenship behavior. Implications and directions for future research are discussed.
The barriers to career advancement of female teachers in Turkey and their levels of burnout
Authors: İnandi Yusuf
Published: November 2009

The purpose of this study was to determine whether the career barriers that female teachers working in Turkish elementary schools have experienced predict their levels of burnout. The correlation research method was used and multiple regression analysis was conducted on data obtained
from 1,076 teachers randomly selected from elementary schools in 7 geographical regions in Turkey. It was found that career barriers resulting from the school and the environment were predictive of emotional exhaustion and level of personal accomplishment, career barriers resulting from societal
gender stereotypes were predictive of personal accomplishment, and career barriers resulting from school and environment predicted depersonalization.
Physicochemical characterization of solid dispersion systems of tadalafil with poloxamer 407
Authors: Vyas Vikrant , Sancheti Pankajkumar , Karekar Poonam , Shah Manali , Pore Yogesh
Published: December 2009

Physicochemical characterization of solid dispersion systems of tadalafil with poloxamer 407

Dissolution behaviour of a poorly water-soluble drug, tadalafil, from its solid dispersion systems with poloxamer 407 has been investigated. Solid dispersion systems of tadalafil were prepared with poloxamer 407 in 1:0.5, 1:1.5 and 1:2.5 ratios using the melting method. Characterization of binary systems with FTIR and XRPD studies demonstrated the presence of strong hydrogen bonding interactions, a significant decrease in crystallinity and the possibility of existence of amorphous entities of the drug. In the binary systems tested, 1:0.5 proportion of tadalafil/poloxamer 407 showed rapid dissolution of tadalafil (DE30 70.9 ± 3.6 %). In contrast, higher proportions of poloxamer 407 (1:1.5 and 1:2.5) offered no advantage towards dissolution enhancement of the drug, indicating altered rheological characteristics of the polymer at its higher concentration, which might have retarded the release rate of tadalafil.
Recommendations for Use of Free Light Chain Assay in Monoclonal Gammopathies
Authors: Radović Vesna
Published: December 2009

Recommendations for Use of Free Light Chain Assay in Monoclonal Gammopathies

The serum immunoglobulin free light chain assay measures levels of free κ and λ immunoglobulin light chains. There are three major indications for the free light chain assay in the evaluation and management of multiple myeloma and related plasma cell disorders. In the context of screening, the serum free light chain assay in combination with serum protein electrophoresis and immunofixation yields high sensitivity, and negates the need for 24-hour urine studies for diagnoses other than light chain amyloidosis. Second, the baseline free light chains measurement is of major prognostic value in virtually every plasma cell disorder. Third, the free light chain assay allows for quantitative monitoring of patients with oligosecretory plasma cell disorders, including AL, oligosecretory myeloma, and nearly twothirds of patients who had previously been deemed to have non-secretory myeloma. In AL patients, serial free light chains measurements outperform protein electrophoresis and immunofixation. In oligosecretory myeloma patients, although not formally validated, serial free light chains measurements reduce the need for frequent bone marrow biopsies. In contrast, there are no data to support using free light chain assay in place of 24-hour urine electrophoresis for monitoring or for serial measurements in plasma cell disorders with measurable disease by serum or urine electrophoresis.
Manly Contests: Rodeo Masculinities at the Calgary Stampede
Authors: Kelm Mary-Ellen
Published: December 2009

Abstract:

The Calgary Stampede is one of Canada's most popular annual festivals. Its long history and its mission to preserve Western values might suggest that its principle character, the cowboy, would be relatively uncomplicated. Yet recent scholarship on popular culture and public celebrations, as well as that on gender and masculinity, encourages a re-examination of the cowboy at the Calgary Stampede. This article examines how the Calgary Stampede constituted cowboy masculinities during the first three decades of the twentieth century. Focusing on the era when the flamboyant Guy Weadick was the Stampede's manager (1912, 1923–32), it first explores how the idea that the West could recuperate masculinity was expressed through a definition of the cowboy that was, in Weadick's words, ‘open to all.’ As rodeo became a sport, a new normative cowboy emerged, as local men, both settler and Aboriginal, took centre stage, excluding women and performers. This paper argues that the Calgary Stampede helped foster the development of new rodeo masculinities for both settler and Aboriginal men, ones grounded in the respectability of sport, and in the economic, social, and political challenges of early-twentieth-century Western Canada.
Death Wore Black Chiffon: Sex and Gender in CSI
Authors: Lavigne Carlen
Published: December 2009

Abstract:

In light of the popularity of television crime dramas, it seems prudent to investigate the political nature of their prime-time messaging. From a feminist perspective, an analysis of gender and sexuality issues in CSI: Crime Scene Investigation reveals that the program consistently associates women, queer cultures, and sexual subcultures with shallow stereotypes, negativity, and death.
Integrating Environmental Perspectives into Pavement Management
Authors: Nathman Rachel , McNeil Sue , Van Dam Thomas J.
Published: December 2009

Sustainability is characterized as a three-legged stool supported by economic, environmental, and social considerations. This paper demonstrates the feasibility of integrating environmental performance measures, one aspect of sustainable practices, into asset and pavement management. To illustrate these concepts, a Microsoft Excel workbook-based pavement construction decision support tool named Pavement Life-Cycle Assessment Tool for Environmental and Economic Effects (PaLATE) is introduced. Background information is given on life-cycle assessment (LCA) pavement construction tools. PaLATE product life-cycle and LCA phases are covered, in addition to PaLATE data and data sources. A table describing the data used for environmental calculations is included, and the use of an asphalt emulsion seal and the use of an ultrathin hot-mix asphalt overlay are compared by use of the tool. Special attention is given to recycled materials and environmental measures. Concluding remarks suggest different contexts for potential applications of PaLATE, together with network tools that can be used to meet user needs and applications as well as to address feasibility and cost.
Quadratic Linear Control Approach to Managing Network-Level Performance Goals of Pavement Infrastructure Systems
Authors: Pantelias Aristeidis , Zhang Zhanmin
Published: December 2009

This paper presents a new formulation and solution to the problem of managing infrastructure-specific, network-level performance goals through the planning of maintenance and rehabilitation (M&R) activities for the case of pavement infrastructure systems. The proposed approach is based on tracking agency-set targets with the use of optimal control theory. In particular, the problem is formulated as a discrete-time, continuous-state-space quadratic linear tracking control problem considering M&R actions for a finite planning horizon. The formulation builds on previous research efforts by using deterministic, yet realistic, empirical deterioration models. The problem is subsequently solved by using a standard nonlinear mathematical programming solver. The results obtained are realistic, and the formulation provides ample modeling flexibility, which allows the decision maker to obtain target-specific optimal solutions.
Mechanistic–Empirical Modeling in Network-Level Pavement Management
Authors: Schram Scott , Abdelrahman Magdy
Published: December 2009

Researchers and practitioners have long recognized the advantages of mechanistic modeling. As agencies implement the Guide for Mechanistic–Empirical Design of New and Rehabilitated Pavement Structures [referred to as the Mechanistic–Empirical Pavement Design Guide (MEPDG)] in the local project-level pavement management system (PMS), its potential as a planning tool in network-level analyses remains unrecognized. A unique, large-scale application of MEPDG is presented. The Nebraska Department of Roads uses a decision tree that systematically screens and identifies candidates for entry into a multiyear optimization program. The process uses linear deterioration rates that have been shown to provide an R2 value as low as 14%. In a retroactive 5-year analysis, 86 sections were prescreened by using the existing models. Predictions indicated that 85 of the 86 sections would have been candidates for maintenance in the first 5 years, whereas field data suggested that only 23 should have been targeted. Calibrated MEPDG distress models calculated with local performance indices replaced the existing linear models. When the analysis was repeated with the mechanistic–empirical models, 35 of the 86 sections qualified for entry into the 5-year analysis, a 70% improvement in the accuracy of the forecasted cost. This research fulfills a timely need for the transitioning of network-level PMS toward mechanistic practices. Consideration of fundamental material properties, climatic conditions, and the structural response to traffic loading provides improved accuracy in planning. Furthermore, production variability and prediction uncertainties can be quantified and used as an additional probabilistic decision-making parameter. Detailed results of the implementation of MEPDG in the local network-level PMS are presented.
Infrastructure Assessment
Authors: Alexander Don R. , Gilbert Robert B.
Published: December 2009

Engineers are being challenged to make critical decisions in response to crisis situations occurring around the globe on a seemingly daily basis. The nature of these crises varies widely and can include military missions as well as humanitarian operations in response to hurricanes, tsunamis, fires, and earthquakes. With thousands of lives hanging in the balance, timely and successful responses to these emergencies often depend on the optimal use of the existing horizontal infrastructure, such as roads, airfields, and railroads, in the affected area. Engineers must provide solutions quickly on the basis of limited data, particularly for unanticipated emergency situations. For military operations, options and alternatives are imperative to the success of a mission. This paper describes an analytical approach to the management of uncertainty because of limited data that provides a solution based on seasonal variability in material strengths, spatial variability in material strengths, and spatial variability in pavement layer thicknesses. An example scenario for an airfield is presented to illustrate techniques for analysis of the structural capacity of pavements of marginal quality and quantification of the uncertainty of the results.
Development of a Management Framework for Rural Roads in Developing Countries
Authors: Chamorro Alondra , Tighe Susan L.
Published: December 2009

During the past decade, considerable efforts have been made to valuate the benefits of investments in rural roads in developing countries. Although the outputs of those studies have led to a global rethinking of traditional road appraisal methods, limited attempts have been made to integrate these findings into the rural road management process. The problem that arises from the analysis is a missing link between the appraisal of the socioeconomic impact and the management of rural roads. The main objective of the present study was to develop a methodology that combined all key aspects required for the sustainable management of rural roads in developing countries. For this, social, technical, economic, political, and sustainability aspects must be considered at the different levels of the management process. A case study developed in Chile is presented to illustrate the application of the proposed framework at the strategic and the network levels. From the application it was concluded that it was possible to combine in a practical and integrated tool all key factors affecting the process of management of rural roads in developing countries.
Development of Distress Guidelines and Condition Rating to Improve Network Management in Ontario, Canada
Authors: Chamorro Alondra , Tighe Susan L. , Li Ningyuan , Kazmierowski Thomas J.
Published: December 2009

In 2006, the Ministry of Transportation of Ontario, Canada (MTO), completed a study with the Centre for Pavement and Transportation Technology at the University of Waterloo to evaluate the performance of automated and semiautomated technologies that collect pavement distress data. From that study it was recommended that MTO define concise guidelines for surveying pavement distresses at the network level by using automated collection technologies and semiautomated distress analysis and for the guidelines to give special attention to quality assurance. In light of that recommendation, the study detailed in this paper presents the development of pavement distress guidelines and a distress manifestation index (DMI) for network-level (DMINL) evaluations by using automated collection technologies and semiautomated distress analysis. To define and validate DMINL, sections evaluated in the previous study were considered. The relative effect of each distress was obtained by linear regression and statistical analysis. The principle used to define the weighting factors was that the distresses considered by the new guidelines should quantify with a minimum error the DMI estimated by the MTO traditional method.
Laboratory and Finite Element Evaluation of Joint Lockup
Authors: Saxena Priyam , Hoegh Kyle , Khazanovich Lev , Gotlif Alex
Published: December 2009

Transverse joints are introduced in portland cement concrete pavements to allow for expansion and contraction due to temperature and moisture variation in the concrete layer. With the use of dowels, the ability of the concrete to expand and contract at the joint may be restrained. This action leads to joint lockup, the severe restriction in the ability of the joint to open and close. Joint lockup had been attributed to rotational misalignments of dowels. The results of this study indicate that other factors may have a greater effect on joint opening behavior. It was demonstrated in the laboratory that dowel misalignment did not significantly increase pullout force for properly greased dowels. It was also found from laboratory testing that a lack of proper greasing significantly increased the dowel pullout force. Dowel–concrete friction was identified as an important parameter that controlled the joint behavior according to the finite element model. High friction may induce damage in concrete and thus cause distresses traditionally attributed to rotational misalignment of dowels; this suggests that designers and contractors should ensure proper bond breaking between dowel and concrete.
Combined Effect of Moving Wheel Loading and Three-Dimensional Contact Stresses on Perpetual Pavement Responses
Authors: Wang Hao , Al-Qadi Imad L.
Published: December 2009

Tire–pavement interaction was analyzed with measured three-dimensional (3-D) tire contact stresses at various load levels (35, 44, and 53 kN) and constant tire pressure (720 kPa). The combined effect of moving wheel load and 3-D contact stresses on flexible pavement response was evaluated with a developed 3-D finite element (FE) model, which incorporated the measured 3-D tire contact stresses, hot-mix asphalt (HMA) viscoelasticity, and continuous moving load by using implicit dynamic analysis. In FE modeling, a perpetual pavement design with 254-mm HMA placed on 305-mm lime-modified subgrade was exposed to dual tire loading. The critical pavement responses under two loading conditions (uniform contact stresses and measured 3-D contact stresses) at various load levels were calculated and compared. The 3-D tire contact stresses induced greater pavement stresses and strains at the pavement near surface (shear strains and octahedral shear stresses) and at deeper depths (transverse tensile strains and compressive strains) comparable to the uniform contact stresses; these results suggest that using uniform contact stresses could underestimate pavement damage, especially near-surface cracking potential and shear flow in perpetual pavement. The transverse tangential stresses induce the outward shear flow from the tire center and shear strain concentration at the pavement near surface. Increasing the wheel load mostly increases contact stresses at the tire edge and the corresponding shear strains and octahedral shear stresses. The difference between pavement responses caused by uniform contact stresses and 3-D contact stresses decreases when wheel load increases.
Full-Depth Reclamation with Engineered Emulsion in Fairburn, Georgia
Authors: Kroge Matthew , McGlumphy Kevin , Besseche Troy
Published: December 2009

In 2006, Virlyn B. Smith Road in Fairburn, Georgia, was determined to be a candidate for reconstruction. Pavement distresses, high seasonal demand from the Georgia Renaissance Festival, overall increased traffic volumes, and the need for lane widening placed Fairburn at the top of the reconstruction list. Instead of traditional methods—full-depth patching nearly 40% of the road followed by a layer of hot-mix asphalt—full-depth reclamation (FDR) with engineered emulsion was chosen. The objective of the project was to improve the structural capacity and widen Virlyn B. Smith Road. The purpose of this paper is to validate the benefits of FDR with engineered emulsion using preconstruction and post-construction falling weight deflectometer (FWD) data from Virlyn B. Smith Road. This paper describes the equipment, materials, and procedures used to reclaim and stabilize Virlyn B. Smith Road and the methods used for data analysis. FWD data taken before and 1 year after construction were compared. The parameters measured by FWD on the road structure are modulus of base and pavement, normalized maximum deflections, and effective structural number. One year after construction, the effective structural number, modulus of base, and modulus of pavement increased significantly and normalized maximum deflections decreased. Resilient modulus analysis was performed on cores taken from the FDR layer in the finished road. The modulus, structural number, and layer coefficient from the cores proved to be higher than those found by FWD analysis. Overall data show improvement in the road structure after stabilization and overlay.
Computational Molecular Analysis of Chloride Transport in Hydrated Cement Paste
Authors: Pan Tongyan , Liu Yajun
Published: December 2009

Concrete in transportation infrastructure is constantly subjected to the ingress of chloride, which could cause reinforcement corrosion and significant deterioration of concrete structures if not well controlled. Major types of reinforcement corrosion, such as pitting corrosion and concentration-cell corrosion, are usually initiated with localized chloride concentrations whose behavior is closely related to the transport characteristics of chloride ions in hydrated cement paste. However, unless studied at the molecular level, chloride transport behavior cannot be properly understood and controlled in view of the high heterogeneity of cement paste. The findings are presented from a research study recently conducted with a molecular dynamics (MD) approach to investigate the physicochemical nature of the various interactions between chloride ions and cement hydration products, which might significantly influence chloride transport in cement paste. Six hydrated compounds including portlandite, C-S-H phases (tobermorite and jennite), AFm phases (hydrocalumite and kuzelite), and the AFt phase (ettringite) were modeled and then validated by using the 35Cl nuclear magnetic resonance spectroscopy technique. On the basis of the MD-generated ionic trajectory, the macroscopic transport phenomenon of chloride species was evaluated in the vicinity of each different hydration product in terms of a computed effective diffusion coefficient.
Sampling and Testing Latex-Modified Concrete for Permeability to Chloride Ion
Authors: Sprinkel Michael M.
Published: December 2009

The overall experience with latex-modified concrete (LMC) overlays constructed with Types I–II, III, and K cements and rapid set cement continues to be good. The most frequent problem with LMC since the late 1990s has been the high incidence of LMC samples failing the permeability test (AASHTO T277) when done at an early age. Approximately one-third of the field-prepared specimens fail because they have permeability values > 1,500 coulombs. Research was done to determine the cause and significance of the failing early-age LMC permeability test results and to recommend changes in practice. The approach included testing of specimens prepared in the laboratory, specimens prepared in the field, and cores from three bridge overlays that had failing early-age test results for field-prepared specimens. Results indicate that the permeability of LMC decreases as the concrete ages. LMC that meets the specification with the exception of early-age permeability should have a very low permeability at later age regardless of the early-age permeability. The permeability test conducted on samples of LMC at early age does not provide a good indication of the later-age permeability of LMC and should not be used to reject LMC.
Recycled Concrete Aggregate Coefficient of Thermal Expansion
Authors: Smith James T. , Tighe Susan L.
Published: December 2009

Despite a critical shortage of virgin aggregate, the availability of demolished concrete for use as recycled concrete aggregate (RCA) is increasing. Using this waste concrete as RCA conserves virgin aggregate, reduces the impact on landfills, decreases energy consumption, and can provide cost savings. However, there are still many unanswered questions about the beneficial use of RCA in concrete pavements. This research studied the effect of RCA on the coefficient of thermal expansion (CTE) and its impact on pavement performance. CTE is a key property of concrete and relates to the amount of expansion and contraction caused by changes in temperature. CTE testing was conducted on 16 cores containing various amounts of coarse RCA (0%, 15%, 30%, and 50%) using a simplified methodology. Testing showed that concrete performance improved as the amount of RCA increased. This result was demonstrated by a decrease in CTE; values for the CTE ranged from 7.28 × 10-6/°C for 0% coarse RCA to 4.10 × 10-6/°C for 50% coarse RCA. The variability of the CTE results was also examined to assess whether the RCA content or simplified testing methodology affected the results. Performance of the RCA concrete was simulated by using the Mechanistic–Empirical Pavement Design Guide. Average, minimum, and maximum CTE values for each RCA amount were used to investigate the sensitivity of this important property on pavement roughness, cracking, and faulting. Simulated pavement performance of all the RCA sections improved as the CTE values decreased.
Modeling of Bond Stresses of Overlay–Bridge Deck System
Authors: Issa Mohsen A. , Alrousan Rajai Z.
Published: December 2009

This study investigated direct and indirect factors influencing the bond strength between the concrete overlay and the bridge deck by using finite element analysis (FEA) and experimental validation. In addition, it presents reliable guidelines for the required bond strength that is needed for concrete to avoid potential delamination under various possible induced stresses. The purpose of the FEA is to predict and correlate the live load– and shrinkage-induced stresses at the interface between the concrete overlay and the bridge deck and to correlate these induced stresses with the direct tensile bond strength of the overlay. Fifteen full-scale prototype bridge systems without and with various thicknesses of overlays were studied. In addition, 42 overlay–bridge deck slab segments were created considering the relative thickness ratio of the overlay to the bridge deck slab ( toverlay/ tslab) and the relative elastic modulus ( Eoverlay/ Eslab). Also, 210 overlay–bridge deck slab segments were created considering toverlay/ tslab, Eoverlay/ Eslab, and slab concrete compressive strength ( f ‘ c). The effectiveness and accuracy of the FEA guideline models were compared with Fowler's guidelines. The FEA results reveal that the live load– and shrinkage-induced shear stresses are about 1.5 to 2.5 times the induced normal stresses, in good agreement with most of the published research. Overlay thicknesses of 38 and 63 mm (1.5 and 2.5 in.) were recommended as the minimum and maximum allowable thicknesses that will prevent the overlay from debonding when the deck is subjected to AASHTO HS-20 truck loading plus impact as well as shrinkage loading.
Pedestrians’ Level of Service at Signalized Intersections in China
Authors: Bian Yang , Ma Junlai , Rong Jian , Wang Wei , Lu Jian
Published: December 2009

This paper attempts to develop a level of service (LOS) model for signalized intersection crosswalks for pedestrians in China by using the pedestrians’ perceptions of comfort and safety. First, three potential factors influencing pedestrian LOS at crosswalks are summarized: traffic conflicts, crossing facilities, and delay. Second, collected data for the model include ( a) information on 653 participants’ real-time sense of comfort and safety when crossing 10 selected intersections and ( b) the design and operational characteristics of the selected intersections. The selected crosswalks are typical of those prevalent in urban areas of China, and the participants in the survey covered a broad cross section of the Chinese population of pedestrians. With the survey data, a Pearson correlation analysis and stepwise regression analysis were carried out to develop a reliable pedestrian LOS model for signalized intersections, suitable for use in the vast majority of Chinese urban areas. The study revealed that the factors significantly influencing pedestrian LOS at signalized intersections included right-turning vehicle and bicycle volume from the street parallel to the crosswalk during pedestrian green time, permissive left-turning vehicles and bicycles approaching from the street parallel to the crosswalk, through bicycle volume on the street parallel to the crosswalk, and pedestrians’ delay.