bluuebunny/crossref_metadata_2025 huggingface dataset:
Does Elastic Anisotropy Significantly Affect a Tunnel's Plane Strain Behavior?
Authors: Tonon Fulvio
Published: May 2007

Rock masses are anisotropic because their properties depend on the orientation considered. The diverging opinions in the literature on whether the elastic anisotropy of a rock mass significantly affects the plane strain behavior of a tunnel are contrasted. A two-dimensional parametric study is presented to answer the questions raised by the literature review. For a given premining state of stress, the stress field around a tunnel in an anisotropic rock mass is not significantly different from the stress field around a tunnel in an isotropic rock mass. For a given anisotropic rock mass, the stress and displacement fields, as well as slip zones, obtained under the hypothesis of no lateral strain are radically different from that obtained under the hypothesis of uniform premining state of stress. In the first case, the slip zones can penetrate more than two diameters into the rock mass, especially for vertical or inclined joints. In the second case, the slip zones extend for a maximum of half a tunnel diameter into the rock mass, regardless of rock mass anisotropy. Displacement vector magnitudes are highly influenced by the elastic anisotropy of the rock mass, even if the premining state of stress is fixed. For a given premining state of stress, slip zones around a tunnel are unaffected by the elastic anisotropy of the rock mass. The slip zones depend only on the orientation of the joints along which slippage can occur.
Prediction of Pier Response to Barge Impacts with Design-Oriented Dynamic Finite Element Analysis
Authors: Consolazio Gary R. , Hendrix Jessica L. , McVay Michael C. , Williams Mark E. , Bollmann Henry T.
Published: May 2007

The loads imparted to bridge piers during barge impact events can be quantified and the structural responses that result from the application of such loads can be determined by using analytical procedures of varying degrees of complexity. At one extreme, sophisticated, nonlinear, dynamic finite element impact simulation techniques may be used to quantify the time variation of the dynamic loads generated during such collision events. At the other end of the spectrum are bridge design specifications with simple computational formulas for computing equivalent static loads for barge impact loading. An intermediate level—design-oriented dynamic finite element analysis technique—that is suitable for use in design practice with moderate computational resources is presented. The proposed method uses barge crush data—predetermined either experimentally or by using high-resolution finite element analysis—to link a design-oriented dynamic pier analysis program to a low-order, nonlinear barge model. For demonstration purposes, the method is implemented in a widely used commercial pier analysis program (FB-Pier). Results obtained from the proposed method, including both dynamic load predictions and structural response predictions, are compared with corresponding results obtained using high-resolution, finite element analyses for validation purposes.
Evaluating Potential for Reflection Cracking with Rolling Dynamic Deflectometer
Authors: Lee Jeffrey L. Y. , Chen Dar-Hao , Stokoe Kenneth H. , Scullion Thomas
Published: May 2007

A common rehabilitation strategy used for repairing aged concrete pavement is to place a hot-mix asphalt (HMA) overlay on the existing concrete pavement. However, reflection cracks are often found to propagate from the underlying cracks and joints through the HMA layer. As such, much reflection cracking is believed to be caused by differential vertical and horizontal movements in the concrete pavement. A common method of determining the differential vertical movements is by measuring the load transfer efficiency (LTE) at the joints by using nondestructive deflection testing devices. A study was conducted with a rolling dynamic deflectometer (RDD) to evaluate the movement of joints in concrete pavements. Evaluation of joint movements by RDD testing permits estimation of the LTE of each joint or transverse crack. On the basis of the assumption that reflection cracks are more likely to form at joints or cracks with low LTE than with high LTE, pavement engineers can use the results to identify areas with low LTE and perform necessary repairs at these locations to reduce the potential for creating reflection cracking. Field data collected before rehabilitation work on US-82 near Gainesville, Texas, are presented as a case study, and the benefits of continuous deflection profiling for use in the district’s rehabilitation strategy are discussed.
A Strong but Flexible Foundation for Chisago County, Minnesota
Authors: Wegman Daniel , Dahlberg Mic , Bray Ronald B. , Lukanen Erland , Thomas Todd
Published: May 2007

Chisago County, Minnesota, has a limited budget and many miles of gravel roads that need increasing expenditures to maintain their current condition. Paving would greatly increase the value of this infrastructure to road owner and road users. However, conventional design and construction methods are too expensive or do not give the needed performance. A team of the county engineer, consultants, a supplier, and a contractor developed a cost-effective method for upgrading Chisago's granular material roads and reducing maintenance costs. The existing gravel road is analyzed and sampled. An emulsion-stabilized base mix is designed with performance-related techniques adapted for emulsion mixes. Structural design is performed with traffic, soil, and falling weight deflectometer data. The gravel is mixed with an asphalt emulsion formulated for optimal coating and curing as well as the desired strength and resistance to thermal cracking. After construction, the newly stabilized base is overlaid with a thin, specially engineered surface mixture or sealed with a chip seal to protect the base from moisture and to improve surface texture. Stabilizing a granular base strengthens it and makes it more consistent. A project using this method was constructed in 2001, followed by nine projects in 2002. The initial project described in this study showed a 40% improvement in granular equivalency of the base. The result was a new, engineered system for a strong but flexible bituminous base and surface, ready for future staged construction when warranted. The design procedure, construction, laboratory test results, costs, and field performance measurements, including structural calculations, are discussed.
Comparison of Performance and Cost Between Superpave and Conventional Hot-Mix Asphalt in Washington State
Authors: Willoughby Kim A. , Weston Jim , Pierce Linda M. , Mahoney Joe P.
Published: May 2007

The Washington State Department of Transportation (WSDOT) began using Superpave® in 1996 and has increased the number of projects each year, totaling approximately 1.9 million tonnes (2.1 million tons) and covering 1,753 lane kilometers (1,089 lane miles). After the Superpave projects had been in place for a maximum of 6 years, an evaluation of the field performance, unit prices, and costs per lane kilometer were compared with WSDOT's conventional hot-mix asphalt (HMA). Although none of the Superpave projects have reached the end of their performance life, the purpose of this limited study is to answer the question, Is Superpave performing as well as conventional HMA in Washington State? The data presented show that, in most cases, Superpave is performing as well as, or better than, conventional HMA and the cost is approximately the same.
Stiffness Estimates Using Portable Deflectometers
Authors: Hoffmann Olivier J. -M. , Guzina Bojan B. , Drescher Andrew
Published: May 2007

The use of falling weight deflectometers and portable falling weight deflectometers (PFWDs) is now common for field characterization of pavement system layers. In particular, the application of portable deflectometers in quality assurance of newly constructed granular base has become more widespread. Typically, these devices are used for an in situ assessment of the Young's modulus of the base layer. The traditional backcalculation uses an elastostatic half-space framework to relate Young's modulus of the pavement foundation to the stiffness estimates obtained from force and velocity measurements. The data interpretation method that is customarily used for stiffness estimation uses peak values of the force and displacement records in lieu of their static counterparts. The performance of a particular device, PRIMA 100, was examined with the newly developed beam verification tester (BVT) of known static stiffness. It was shown that the conventional, peak-based method of backanalysis produces incorrect estimates of the static stiffness of the BVT. An alternative, spectral-based data interpretation method was proposed. This method, based on ( a) concept and measurement of the frequency response function and ( b) a single-degree-of-freedom mechanical model, was employed to extract the true static stiffness from PRIMA 100 measurements. The results show a good agreement between the true static stiffness of the BVT and its PFWD estimates stemming from the modified approach. The BVT apparatus can therefore be used to assess the performance of the sensors and data interpretation of PRIMA 100-type deflectometers.
Subgrade Characterization Employing the Falling Weight Deflectometer
Authors: George K. P. , Bajracharya Manil , Stubstad Richard
Published: May 2007

Subgrade soil characterization expressed in terms of resilient modulus ( Mr) has become crucial for pavement design. For new pavement design, Mr values are generally obtained by conducting repeated load triaxial tests, employing TP46/P46 protocol. Because of the complexities encountered with the test, in situ tests would be desirable if reliable correlations could be established. This study investigates the viability of using the falling weight deflectometer (FWD) for direct testing of subgrades with the objective of deriving resilient moduli by means of a correlation between FWD moduli and TP46 Mr values. Ten as-built subgrade sections, reflecting typical subgrade soil materials in Mississippi, were selected and tested with the FWD. Undisturbed samples were extracted by using a Shelby tube and tested in a repeated-load triaxial machine for Mr, employing the TP46 protocol. In addition, other routine laboratory tests were conducted to classify the soils. In the suggested approach making use of seven FWD sensor deflections, elastic moduli, E1 to E7, are calculated through forward calculation equations (assuming an elastic half-space). The first sensor modulus, E1, and an average offset sensor modulus, E3-5 (i.e., the average of E3, E4, and E5), are regressed against Mr, advancing two models for Mr prediction. By employing E1 and E3-5, two distinct resilient moduli are derived with the lesser of the two serving as the "design resilient modulus." A feature of the approach is that the entry into the process of both the center sensor modulus and the offset sensor modulus ensures proper subgrade characterization, even when significant nonhomogeneity in a subgrade profile is being encountered.
Models Relating Pavement Quality Measures
Authors: Aultman-Hall Lisa , Jackson Eric , Dougan Charles E. , Choi Soon-Nam
Published: May 2007

A large field-measured international roughness index (IRI) data set was collected in the summer and fall of 2001 on 650 highway kilometers with sections containing full-depth hot-mixed asphalt (HMA) and HMA over portland cement; the set was used to investigate the relationships between IRI, rutting, and pavement cracking. Parametric statistical analysis, linear regression, and neural network models were used with a large database of 65,530 observations (10-m intervals). The goal was to investigate the relationship between both rutting and cracking (estimated from photolog images obtained at the same time field data were collected) and IRI. Specifically, the objective was to determine if these relationships were consistent enough to allow IRI, the more easily measured quantity, to be used as a surrogate for the others or if the effort and resources to collect all three measures were necessary in pavement management programs. The results indicate that while statistically significant relationships exist between IRI and both cracking and rutting, these relationships are not strong enough for IRI to be used as a surrogate measure for pavement condition. The weak predictive relationships are further evidenced by the lack of success in training a neural network that could significantly outperform linear regression models. It was concluded that IRI, while appropriate for measuring rideability, was not appropriate for measuring cracking or rutting.
Wavelength-Related Ride Equation
Authors: Walker Roger S. , Fernando Emmanuel , Bertrand Carl
Published: May 2007

The existing equation used by the Texas Department of Transportation (TxDOT) to evaluate ride quality from measured profiles is based on measurements obtained from a rating session conducted in the late 1960s. Since its original development more than 30 years ago, a number of changes have required a reevaluation of the current equation. These include changes in vehicle design, such as improvements in vehicle suspension and handling characteristics, and the switch from the predominantly large automobiles used in the late 1960s to the smaller and more fuel-efficient midsized and compact cars of today. Additionally, TxDOT has changed the section interval used for reporting ride or present serviceability index from 0.2 to 0.1 mi. A new ride equation based on a specific set of profile wavelengths is described. In addition, possible uses of the equation for construction control and bump detection are discussed.
Assessment of the Transfer Penalty for Transit Trips Geographic Information System-Based Disaggregate Modeling Approach
Authors: Guo Zhan , Wilson Nigel H. M.
Published: May 2007

Transit riders negatively perceive transfers because of their inconvenience, often referred to as a transfer penalty. Understanding what affects the transfer penalty can have significant implications for a transit authority and also lead to potential improvements in ridership forecasting models. A new method was developed to assess the transfer penalty on the basis of onboard survey data, a partial path choice model, and geographic information system techniques. This approach was applied to the Massachusetts Bay Transportation Authority subway system in downtown Boston. The new method improves the estimates of the transfer penalty, reduces the complexity of data processing, and improves the overall understanding of the perception of transfers.
Productivity Analysis in Heterogeneous Operating Conditions: Data Envelopment Analysis Method Applied to the U.S. Heavy Rail Industry
Authors: Martinez Manuel J. , Nakanishi Yuko J.
Published: May 2007

The problem of productivity analysis and heterogeneous operating conditions in the transit industry is addressed. A new method, sequential data envelopment analysis (DEA), is presented. This method accounts for the operating conditions of transit agencies by using a two-step procedure involving DEA and statistical analyses. Sequential DEA was applied to 14 rail transit systems in the United States for the years 1984-1997 to determine productivity levels. The output analyzed was passenger miles, and the three operating conditions selected for inclusion in this nonparametric analysis were population density, transit share of the journey to work trips, and station availability. The results of the sequential DEA productivity analysis indicate that the rail transit industry, on average, operates at a technical efficiency of 76% in using its fixed input. This result is 8% higher than the efficiency levels estimated by conventional DEA. In addition, the referent agencies and optimal output levels for each agency were identified.
Rail Access Pricing for Suburban Services in Europe
Authors: Tsamboulas D. , Kopsacheili A. G.
Published: May 2007

Until recently, Europe was dominated by state-owned, vertically integrated railroads. Lately, European Union (EU) policies and relevant legislation have introduced the legal separation between railroad operations and infrastructure management. Thus, the railroad infrastructure management companies have started applying charges (termed access pricing) to railroad companies for using infrastructure. Although European policies and legislation set the basic access pricing principles, they did not provide specific rules or methods for deriving infrastructure charging systems. An access pricing system for suburban (commuter) rail services was developed. An overview of practices in EU member states and the United States is presented. The basic principles and economic characteristics of infrastructure charging are outlined. The proposed structure of the infrastructure charging system is discussed, with a distinction between the basic charge-which includes costs for train planning and line operations, infrastructure damage and wear and tear costs, and quality of services-and additional components. Each component is mathematically expressed. The proposed charging system does not include costs related to train operations. To test the robustness of the proposed system, it is applied to the suburban rail services provided by the Greek company AMEL, with trains running on the Greek railroads' infrastructure. The proposed infrastructure charging system can be applied to any railroad by changing the variable values.
Suburban Silver Bullet: Personal Rapid Transit Shuttle and Wireless Commuting Assistant with Cellular Location Tracking
Authors: Raney Steve
Published: May 2007

In a hypothetical year 2008 scenario, a personal rapid transit (PRT) circulator shuttle system and comprehensive door-to-door, new-mobility service transform the major employment center of Palo Alto, California, into a 2-mi transit village, complementing and significantly increasing the attractiveness of rail, carpool, vanpool, bicycle, and bus commutes for the center's 20,000 employees. Of utmost importance, PRT is faster than a person driving alone in the last mile. A transportation management association enables a supportive commuting culture. A larger candidate pool accesses the personal, web-based ride-matching service, MatchRide and increases carpool formation. New applications of cellular location-tracking technology and wireless-enabled handsets are proposed to increase the competitiveness of suburban commuting alternatives. Cellular phones evolve to become a commuter's command center, an integral part of the workday. The following applications are proposed: (a) TrakRide to improve the reliability of carpool rendezvous and increase courteous, punctual behavior; (b) NextTrain to improve the reliability of train-shuttle connections; (c) HomeSafe to ensure that carpools of strangers operate safely; (d) QuickCar to provide 5-min access to cars for centralized carsharing and emergency ride home with wireless door key; (e) SpyKids to maintain secure custody of children during unaccompanied shuttle trips; and (f) NextSpace to direct commuters to available parking spaces, with wireless access to automated, shared parking lots. A central database, known as Big Sister, maintains personal data to support these applications.
Load Planning with Uncertain Demands for Time-Definite Freight Common Carriers
Authors: Lin Cheng-Chang
Published: May 2007

Time-definite common carriers are third-party logistics providers that publish tariffs and provide door-to-door pickup and delivery services for small shippers. Their time-sensitive transport operations are critical outsourced activities for a successfully integrated supply chain. In a pure hub-and-spoke network, centers are points of pickup and delivery while hubs are points of consolidation. When the magnitude of demand is uncertain, the stochastic load-planning problem is to determine freight paths and design a balanced trailer network so that expected operating cost is minimum while integral and operational side constraints are met. Demands are assumed to be a finite discrete distribution. Both the first phase and the recourse are pure integer programs. As a result of study of necessary conditions, a heuristic solving algorithm was developed. As a representative example, a small hub-and-spoke network of the third largest carrier in Taiwan was selected for numerical experiments. Results showed a small fleet size with lower operating costs than with the conventionally used deterministic load plan. Stochastic planning is sensitive to the demand fluctuation, whereas deterministic planning is not. Also, the larger the deviation from estimated shipping demand, the higher the operating cost. Finally, if the carrier must pay a higher wage rate for standby drivers, the carrier must assign a larger feeder fleet to anticipate a surge in demand.
Impact of Traffic Congestion on Trade and Strategies for Mitigation
Authors: O'Mahony Margaret , Finlay Hugh
Published: May 2007

Traffic congestion is proving to be a major cost and inconvenience for many businesses and companies, particularly those whose activities demand high levels of transport per unit of production. Following the recent period, from the mid-1990s to today, of heightened economic activity against the background of years of underinvestment in transport infrastructure, Irish businesses are no exception. Analysis was conducted on the results of a survey conducted on Irish businesses in three sectors—manufacturing, distribution and sales, and services—to estimate the impact of traffic congestion. The opinion of the companies was also sought on how they believe transport strategies by the government under the National Development Plan and new infrastructure, either under construction or proposed, will relieve traffic congestion. Finally, the survey investigated what type of strategies companies had used or would consider using to mitigate the negative impacts of traffic congestion. Those policies examined included relocation, flexible working hours, teleworking, and provision of alternative transport for staff. The findings indicated that traffic congestion has an impact on a large proportion of companies to a major degree, particularly when one considers road haulage costs, delivery schedules from the company, and staff punctuality. To mitigate the negative impacts, the strategies that have been used most by companies are flexible working hours, teleworking, and contracting out the distribution function—with relocation and moving the distribution function to the rail mode being less popular than other approaches.
Finding the Number of Yard Cranes Needed to Achieve Desired Truck Turn Time at Marine Container Terminals
Authors: Huynh Nathan , Walton C. Michael , Davis Jeff
Published: May 2007

Because of environmental concerns, terminals are increasingly looking to reduce their truck turn time. Terminals are also looking to reduce truck turn time so that they can lower the inland transportation cost of shipping a container. For terminals that stack their containers, the solution may seem obvious: add more yard cranes. However, the high cost of those cranes often prohibits terminals from freely buying more. Another reason terminals are reluctant to add more yard cranes is that there is no clear understanding of how yard cranes affect truck turn time. A study introduces a simulation model for the analysis of truck turn time with respect to crane availability and deployment. This effort is accomplished by modeling the precise movements of trucks and yard cranes. The developed model uses the Barbours Cut Container Terminal of the Port of Houston Authority as a test bed to demonstrate how it can be applied to find the number of yard cranes needed to achieve a desired truck turn time. Other uses of the model include testing the crane deployment methodology, examining the effect of crane failure, and analyzing the impact of an appointment system.
Improving the Intermodal Freight Transport System Linking Western Europe with Central and Eastern Europe: Identifying and Prioritizing Policies
Authors: Walker Warren E. , van Grol H. J. M. , Rahman S. Adnan , Lierens Abigail , Horlings Edwin
Published: May 2007

A major objective of the European Commission (EC) is to strengthen the position of intermodal transport to make it competitive with road transport. In particular, the EC would like to remove obstacles impeding the use of intermodal transport between Western Europe and Central and Eastern European countries. There is a description of work performed for the EC that examined the existing intermodal transport system, identified the major bottlenecks in the system, and identified and prioritized policies that the EC might implement for reducing the negative effects of the bottlenecks. Identification and prioritization of bottlenecks are described. Through desk research and surveys of forwarders, terminal operators, and link operators, 35 groups of bottlenecks were identified. They were prioritized with a set of 11 performance criteria determined on the basis of surveys. Also, identification and prioritization of policies are described. One or more policies were identified to help solve each of the bottlenecks. The resulting set of 70 policies was evaluated and prioritized by experts by using 6 performance criteria and 5 feasibility criteria. A final set of 7 policies for reducing the negative effects of the most important bottlenecks was recommended to the EC.
U.S. Containerized Grain and Oilseed Exports: Industry Survey
Authors: Vachal Kimberly , Reichert Heidi , Van Wechel Tamara
Published: May 2007

Containerization has evolved from an industry serving niche markets to an industry creating niche market opportunities. Although the grain and oilseed industry is dominated by bulky, homogenized product marketing that is heavily reliant on economies of scale in delivering competitively priced commodities, technological advances, foreign market privatization, and declining global market transaction costs have supported diversification of this industry in niche markets such as small-volume containerized products. The findings of this research suggest that an established and growing U.S. shipper population is active in marketing containerized grains and oilseed products. A survey of shippers suggests that premiums for containerized grain and oilseed products are $5 per hundredweight, compared with premiums for the local bulk counterpart market. The net return to shippers is opaque as business practices and market fundamentals influence the costs associated with delivering the product to a customer overseas versus a local grain terminal or processor. Assuming that market activity is positively correlated to profitability, the grain and oilseed container shippers appear to be achieving acceptable levels of profit. Shippers report that container exports increased annually between 2000 and 2002, and they are projecting it will increase another 20% by 2005. Although many factors affect industry ability to realize this growth, shippers deem ocean freight rates as most crucial. Ocean liner routes and services, distance to container terminal, and foreign buyer information are also rated as having above-average importance.
Using a Single Test to Determine Specific Gravity and Absorption of Aggregate Blends
Authors: Hall Kevin D.
Published: May 2007

The ability to measure the specific gravity of an aggregate accurately and consistently is paramount to transportation materials engineers. Current standard test methods (AASHTO T-84 and T-85) typically are not used for routine quality control purposes because of long testing times and questions about variability. Among new techniques developed for measuring specific gravity and absorption is a vacuum-sealing method, which eliminates the need for long soaking periods and for determining aggregate mass in a saturated-surface-dry moisture state. The vacuum-sealing method also has the potential to measure the specific gravity of a blend of aggregates in a single test. Specific gravity and absorption of six coarse and four fine aggregates composed of various mineralogy types were measured by both traditional and vacuum-seal methods. Ten blends, whose gradations generally met Superpave® hot-mix asphalt specifications, were created by using various combinations of aggregates and tested in a single vacuum-seal test. Five replicate tests were done on all individual aggregates and blends. Aggregate-blend single-test results (specific gravity and absorption) were compared with values obtained with traditional individual test results and mathematical combinations. The comparisons yielded generally strong correlations among methods, indicating the vacuum-seal procedure has promise as a relatively rapid method for determining specific gravity and absorption in a single test of an aggregate blend. However, some real differences in test values suggest that the vacuum-seal method needs refinement before it can be seamlessly substituted for traditional methods.
Evaluation of New Test Procedures for Determining Bulk Specific Gravity of Fine Aggregate by Automated Methods
Authors: Prowell Brian D. , Baker Nolan V.
Published: May 2007

Two automated methods were evaluated for determining the dry bulk specific gravity ( Gsb) of fine aggregates: Thermolyne SSDetect and InstroTek CoreLok. Each proposed method was evaluated against the standard method described in AASHTO T-84. The evaluation was based on a round-robin study with 12 laboratories and six materials, four crushed fine and two uncrushed (natural) fine aggregate sources. The CoreLok and SSDetect methods of determining fine aggregate specific gravity offer significant timesavings over AASHTO T-84. Both the CoreLok and SSDetect methods generally produce Gsb results similar to AASHTO T-84. It is believed that AASHTO T-84 may not produce accurate results for angular materials with high dust contents. More frequent statistical differences exist between the CoreLok and SSDetect apparent specific gravity (Gsa) and water absorption results than those produced by AASHTO T-84. However, Gsa and water absorption are not used in volumetric calculations for hot-mix asphalt. SSDetect offers improved precision over AASHTO T-84. The precision of the CoreLok method is slightly worse than that of AASHTO T-84, but it is expected to improve as technicians become more familiar with the procedure.
Equivalency of Crushed Rock and Three Industrial By-Products Used for Working Platforms During Pavement Construction
Authors: Tanyu Burak F. , Benson Craig H. , Edil Tuncer B. , Kim Woon-Hyung
Published: May 2007

A study was conducted to define an equivalency criterion for five materials used for working platforms during pavement construction on a poor subgrade: conventional crushed rock (referred to as breaker run) and four alternatives (Grade 2 gravel, foundry slag, bottom ash, and foundry sand). A layer of alternative material was considered equivalent if the total deflection of the alternative material was equal to that of breaker run under the same construction loading. Total deflection data for the equivalency assessment were obtained from a large-scale model experiment (LSME) simulating a prototype-scale pavement structure. Total deflections obtained from the LSME were checked against deflections measured in the field with a rolling wheel deflectometer and with an analytical method developed for unpaved roads. Design charts were developed for selecting the equivalent thickness of alternative working platform materials so that the alternative and a layer of breaker run provided equal deflection.
Resilient Modulus Models for Compacted Cohesive Soils
Authors: Ooi Phillip S. K. , Archilla A. Ricardo , Sandefur Kealohi G.
Published: May 2007

Three-parameter models have been used to represent the effects of confining and shear stresses on the value of resilient modulus. A new generation of such models allows better characterization of the variation of resilient modulus at low deviator stress. These models can be extended to incorporate the effects of soil type, soil structure, and the soil physical state (combination of molding water content and dry unit weight) by relating the three parameters to explanatory variables consisting of common soil parameters. A simple methodology was applied to the results of 78 resilient modulus tests on low- and high-plasticity silts from the island of Oahu, Hawaii, to optimize the choice of explanatory variables. Then, the nonlinear ordinary least-squares method was used to estimate the model parameters. The results indicate that the new generation models not only provide a better fit than the older models, but they also provide a reasonable fit to the data that can capture the effects of stress state, soil type, soil structure, and the soil physical state quite effectively.
Using Time-Domain Reflectometry for Real-Time Monitoring of Subsidence over an Inactive Mine in Virginia
Authors: O'Connor Kevin M. , Crawford Joseph , Price Kelvin , Sharpe Roger
Published: May 2007

Closure activities at the United States Gypsum Company facility in Plasterco, Virginia, include realignment of an existing highway outside the predicted limits of long-term subsidence. Concerns about the possibility of subsidence along the existing highway being induced by construction activities, or in the former plant area where excavated rock was being placed, motivated the installation of a real-time monitoring system based on time-domain reflectometry (TDR). This technology involves interrogating solid metallic coaxial cables to determine locations and magnitudes of cable deformation. When the cables are grouted into drill holes and trenches, TDR can be used to determine the location and rate of precursor subsurface movement that is causing cable deformation. Manual monitoring of three cables began in June 2001. Then, during 2002, system capabilities were expanded to automated real-time monitoring of 21 cables with lengths that varied from 10 m (30 ft) to 270 m (886 ft) for a total greater than 2,500 m (greater than 8,200 ft) of cable. The cables were installed in angled holes beneath the existing highway, in trenches along the highway, and in trenches over the former plant area where rock excavated for the new alignment was being placed. The automated monitoring system was controlled by a programmable data logger and incorporated a callback capability. Whenever the difference between the baseline measurement and the current measurement at any location along a cable exceeded a preset alarm threshold, the data logger would initiate a call to responsible personnel.
Seasonal Variations of a Subgrade Soil Resilient Modulus in Southern Brazil
Authors: Ceratti Augusto Jorge , Gehling Wai Ying Yuk , Núñez Washington Peres
Published: May 2007

The influence of suction on the resilient modulus of a shale residual lateritic soil was analyzed. Laboratory tests were carried out to obtain the moisture content-suction relationship and determine the resilient moduli of specimens submitted to drying, wetting, or wetting-after-drying paths. A supplementary study on the effects of compaction method on soil resilient modulus was carried out. Soil suction was measured in situ, with jet-fill tensiometers installed along test sections built in a pavement testing facility. Test sections were loaded by a traffic simulator, and periodically deflections were measured for modulus backcalculation. Laboratory and in situ results confirmed the consensus that suction remarkably affects soil elastic deformability. Wetting-after-drying paths proved to be an extremely severe condition that may lower resilient modulus up to four times. Static compaction led to resilient moduli higher than those of specimens compacted dynamically or by kneading. In situ results matched reasonably well with laboratory moduli of specimens compacted by kneading and tested at optimum moisture content. In general, the importance of drainage design and maintenance was clearly confirmed. In well-drained pavements, subgrade soils will not be saturated for long periods. Suction will control stress state and soil deformability and guarantee that the pavement will carry the designed traffic before failure.
Lifting All Seasonal Load-Restrictions in Norway in 1995 Background and Effects
Authors: Refsdal Geir , Senstad Paul , Soerlie Arne
Published: May 2007

To preserve invested capital and to protect the existing road network against excessive damage during thaw periods, the Norwegian Road Authority adopted extensive axle load restrictions on both national and county roads up to 1995. On January 1, 1995, all axle load restrictions during the spring thaw period within national and county road networks were lifted after calculations indicating that the total efficiency gain after an administrative lifting would be considerable, provided it was followed by extra funds to maintain the surfacing serviceability. However, without such extra funds, a lifting of restrictions would result in reduced surfacing serviceability and considerably increased cost for all road users. As of 2003, there are no indications that the lifting of load restrictions in 1995 has resulted in reduced road surfacing serviceability. This is remarkable, as the annual budgets for resurfacing during the same period have been considerably reduced. One or more of the following items can explain why it has been possible to maintain the road surfacing serviceability at the 1994 level during a period with reduced budgets: road users have not fully utilized the new possibilities in higher axle loads; there has been a slow but steady increase in surfacing service life from 1985 to 2002 from 10 to 15 years for national roads and from 13 to 18 years for county roads; there has been a reduced use of studded tires during winter; and there has been a general development of asphalt techniques and procedures, such as thin surfacings.
Framework for Analyzing Effects of Spring Load Restrictions
Authors: Levinson David , Li Ning , Zou Xi , Smalkoski Brian , Hashami Maryam
Published: May 2007

Spring load restrictions (SLR) impose restrictions on heavy trucks during the spring thaw period. Although the policies have been implemented for many years, their economic effects on truckers remain uncertain. This study provides an overview of practices around the world and sets up a framework to estimate the benefit-cost of the SLR policy. A freight demand model in Minnesota was built to estimate the impacts of SLR on the freight transportation pattern. The model allows various policy scenarios to be tested before being put into practice. A preliminary result of the freight demand model indicates the SLR policy increased truck vehicle kilometers of travel in Lyon County, Minnesota, by about 13%.
Using a Web-Based Longitudinal Panel to Measure Customer Satisfaction
Authors: Spitz Gregory , Pepper Janice , Chakravarti Varoti , Adler Thomas , Niles Frances
Published: May 2007

The benefits of using web-based longitudinal panels for customer satisfaction studies are described according to the experience of such a study for the rail customers of New Jersey Transit (NJ Transit). Numerous benefits of this method are noted over cross-sectional studies, including more robust statistics, better understanding of customer satisfaction, and the ability to analyze customer satisfaction trends. Various innovative Internet technologies, as described, add value to the study by ensuring data quality, timeliness, reduced respondent burden, less random error in respondent answers, and the ability to pair qualitative data to quantitative analysis. Online geocoding of respondents' origins and destinations is also described as another aspect of the survey that provides NJ Transit more value from the study. The details of how the study was implemented for NJ Transit are described, and some results as an example of the beneficial aspects of the study design are reported.
Using multiple‐mode models for fitting and predicting the rheological properties of polymeric melts. II. Single and double step‐strain flows
Authors: Jiang B. , Kamerkar P. A. , Keffer D. J. , Edwards B. J.
Published: May 2007

Several classes of multiple‐mode rheological constitutive equations are examined for predicting the viscoelastic flow properties of a typical polymer melt in single and double step‐strain flows. The phenomenological parameters appearing in these models have been obtained by the fitting of experimental data taken in small‐amplitude oscillatory shear and steady shear flows. The performance of the models for predicting the experimental data in the step‐strain experiments is examined in detail. Specifically, we examine whether or not mode coupling is necessary to describe the experimental behavior under step‐strain flows. Furthermore, it is demonstrated that the reversing double step‐strain experiment is a very powerful tool for testing viscoelastic constitutive equations. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
In the beginning: the initiation of meiosis
Authors: Pawlowski Wojciech P. , Sheehan Moira J. , Ronceret Arnaud
Published: May 2007

The most‐critical point of reproductive development in all sexually reproducing species is the transition from mitotic to meiotic cell cycle. Studies in unicellular fungi have indicated that the decision to enter meiosis must be made before the beginning of the premeiotic S phase. Recent data from the mouse1 suggest that this timing of meiosis initiation is a universal feature shared also by multicellular eukaryotes. In contrast, the signaling cascade that leads to meiosis initiation shows great diversity among species. BioEssays 29:511–514, 2007. © 2007 Wiley Periodicals, Inc.
Neurotrophic Sesterterpenes Isolated from a Marine Sponge, Spongia sp.
Authors: Tokue Takanori , Miura Shunsuke , Kato Hikaru , Hirota Hiroshi , Ohta Tomihisa , Tsukamoto Sachiko
Published: May 2007

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Dimensions of neopentecostal Identity in the Church of England
Authors: Ball Peter
Published: May 2007

Examined the dimensional structure of identity among neopentecostal Anglicans, applying an analogy between glossolalia and ethnic languages, based on intergroup theory.

Similarity data obatined from a card‐sorting task performed by 29 non‐glossolalic and 49 glossolalic members of Church of England congregations were multidimensionally scaled. The resulting dimensional structures indicate that neopentecostalists define themselves mainly in terms of conventional religious markers: ‘rebirth’ experience, belief in scriptural authority, and, for non‐glossolalists, regular prayer. Glossolalia plays only a limited role, and does so only for those who practise it, while denominational affiliation appears to have no significance in religious identity at all. It is suggested that neopentecostalists regard themselves as having marginal status in mainstream churches and aim to distinguish themselves from ‘nominal’ Christians, thus identibing with all devout believers, in preference to emphasizing neopentecostal distinctiveness which does not afford favourable enough social comparisons.
Acquaintance and visual behaviour between two interactants. Their communicative function for the impression formation of an observer
Authors: Abele Andrea
Published: May 2007

Predictions concerning the formation of impressions on the visual of the visual behaviour of an observed person are tested in two experiments.

Observers were shown a video recording of a conversation between two persons in which person (A) looked at his partner (B) or not depending upon the experimental conditions. In addition, the observers were told whether or not the persons were acquainted with one another before this conversation.

It was found, as predicted, that a was rated higher with regard to friendliness und openness if he looked at his conversation partner. Equally in agreement with prediction it was found that the significance of visual behaviour for the formation of impressions is greater if it is known that the observed persons are well acquainted. Ratings of A's dominance and activity are only dependent on the visual behaviour shown if it is known that the observed persons know eath other. In the case in which the partners are not acquainted, there is no such effect.

These results show that the communicative function of visual behaviour over and above the ascription of friendliness and openness is increased if contextual information is given concerning the interpersonal relationship between the persons observed. The formation of impressions concerning the second person involved in the conversation is not influenced by the visual behaviour of his conversation partner.
Self‐awareness and drive theory: Comparing internal standards and dominant responses
Authors: Hormuth Stefan E.
Published: May 2007

Self awareness theory proposes that behavioural and cognitive changes following self‐ focused attention result from a comparison between a salient behavioural or cognitive aspect of the person and a relevant internal standard of correctness. Generalized drive has been offered as an alternative interpretation not requiring the assumption of a mediating cognitive process. The notion was tested that an internal standard of correctness, and not response dominance, guides behaviour following self‐focused attention. The internal standard used, originality, was to be contrary to dominance. Subjects high or low on this standard were assigned to either a self‐awareness, an arousal, or a control condition. First, response dominance was clearly established on a paired associates task. Then subjects' own associations to the stimulus words were obtained. In the self awareness condition, the originality of responses corresponded to internal standards. Responses in the arousal condition were not as predicted, but could be interpreted through the presumption that the particular operationalization of arousal raised not only drive level but also provided self‐related stimuli. The data imply that internal standards of correctness and not response dominance influence the behaviour of those whose attention is self focused.
Polarizing effects of intergroup comparison
Authors: Reid Fraser J. M.
Published: May 2007

Compared the effects of intergroup and within‐group comparison on attitudes differentiating two well‐defined student groups. Social work students (n = 48) expressed attitudes either before or after estimating ingroup or outgroup (commerce students) norms. Subjects adopted more extreme attitudes following outgroup comparison, but were unaffected by comparison within the group.
Source credibility, attitudes, and the recall of past behaviours
Authors: Olson James M. , Cal A. Victoria
Published: May 2007

The hypothesis that individuals' memory for their past behaviours may be biased toward apparent consistency with their current attitudes was tested by exposing subjects to a message that argued against frequent toothbrushing. Some subjects believed that the source of this message was an expert (high credibility condition), whereas other subjects learned after the message that the speaker was misinformed (low credibility condition). Subjects in the high credibility condition expressed less favourable attitudes toward toothbrushing and reported that they had brushed their teeth less often in the preceding four weeks than did subjects in the low credibility condition. A three‐week follow‐up showed that the attitudinal difference was still significant but that estimates of past toothbrushing did not differ reliably between the two conditions. The results suggest that when attitudes are very salient, they increase the accessibility of consistent behaviours in memory.