bluuebunny/crossref_metadata_2025 huggingface dataset:
Seasonal and spatial variations in characteristics of Lake Biwa dissolved organic matter: sorption of pyrene and its derivatives and fluorescence properties
Authors: Kusakabe T. , Ikeda K. , Shimizu Y. , Higashi S. , Kawabata Y. , Kitamura T. , Suzuki Y.
Published: November 2008

The objectives of this research were to investigate seasonal and spatial variations in (1) sorption of pyrene and its derivatives onto dissolved organic matter (DOM) and (2) fluorescence properties of DOM in Lake Biwa, Japan. In the case of pyrene, sorption coefficient (Kdoc) of Lake Biwa DOM seasonally changed from 1,200 to 3,800 L/kgC. Vertical distribution of Kdoc was affected by thermocline formation in summer, while it was uniformly distributed as a result of vertical mixing in winter. Functional groups affected sorption of pyrene onto Lake Biwa DOM in different manner from that onto Suwannee River fulvic acid. Three-dimensional excitation emission matrices (3D-EEMs) fluorescence spectroscopy was applied to characterize Lake Biwa DOMs and indicated the existence of at least two fluorophores. The two major peaks at Ex230/Em300 and Ex230/Em425 originated from protein-like and fulvic/humic-like substances, respectively. The peak at Ex230/Em300 showed the maximum fluorescence intensity at a depth of 5 m and could be affected by stratification of the water column in summer. On the other hand, the peak at Ex230/Em425 showed similar profiles both in summer and in winter. These results demonstrably showed that sorption of micropollutants and fluorescence properties of Lake Biwa DOMs were seasonally and spatially varied.
Utilization of activated sludge plants for enhanced treatment of combined sewage
Authors: Nikolavcic B. , Svardal K. , Wandl G. , Günther N. , Spatzierer G.
Published: November 2008

A process is introduced which utilizes secondary clarifiers for the treatment of combined sewage. Under storm water conditions, surplus sewage bypasses the aeration tanks after primary treatment and is directly introduced into the secondary clarifiers. The hydraulic capacity of existing activated sludge plants can be increased without additional tank volume. Particulate matter as well as dissolved compounds are removed to a high extent. Investigations on a full scale treatment plant (100,000 p.e.) show that the effluent quality is comparable with full biological treatment, even if the hydraulic loading is increased by 50%.
Electromagnetic plane-wave scattering from a sectorial groove in a perfectly conducting plane
Authors: Tsaur Deng-How , Chang Kao-Hao
Published: November 2008

Scattering characteristics of plane waves by a sectorial groove in a perfectly conducting plane are investigated. Both the transverse magnetic (TM) and transverse electric (TE) polarizations of the incident wave are considered. Judicious use of the region-matching technique provides a rigorous series solution to the problem. The analyzed region is separated into two sub-regions by choosing a semi-circular auxiliary boundary. Thefield in each sub-region is expanded as a summationof proper wave functions with unknown coefficients. Enforcing the matching of conditions on the auxiliary boundary and of boundary condition on the circular-arc surface of the groove leads to a linear set of equations and the unknown coefficients are then determined. Numerical results demonstrate the influence of central angles of the sectorial groove on echo width, far-field pattern and near-field distribution. The presented geometry is easily applicable to the design and fabrication of a grating structure for optical switches and tunable filters.
Controlling chaos by developing spiral wave from heterogeneity in excitable medium
Authors: Chen Jiang-Xing , Xu Jiang-Rong , Zhang Xiang-Peng , Zhang Ju-Wang , Zhang Xiao-Wei
Published: November 2008

We study pattern formation induced by a spiral wave developing from heterogeneities in an excitable medium. Turbulence can be suppressed by a spiral wave from the heterogeneity, forming multiple coexistent systems of regular geometrical patterns. We find that the types of these patterns depend critically on the degree of heterogeneity. The underlying mechanism is due to dispersion relation which is characterized by excitability.
Shoulder dystocia related fetal neurological injuries: the role of diabetic control
Authors: Iffy Leslie , Brimacombe Michael , Varadi Valeria , Raghuwanshi Maya , Ganesh Vijaya , Raju Vijaya
Published: November 2008

The study explores the roles of routine prenatal diabetic screening and control in the occurrence of neurological birth injuries associated with shoulder dystocia. The investigation involved retrospective review of 226 medical records that contained information about the antenatal events in cases that resulted in permanent neonatal injuries following arrest of the shoulders at delivery. Close attention was paid to diabetic screening and management of mothers with evidence of glucose intolerance. Analysis of the records revealed that one-third of all women, including those with predisposing factors, received no diabetic screening during pregnancy. The majority of confirmed diabetic patients were not treated adequately. Among babies of diabetic women, birth weights exceeding 4500 g were about 30-fold more frequent than among those with normal glucose tolerance. The data suggest that universal screening and rigid diabetic control, including mothers with borderline glucose tolerance, are effective measures for the prevention of excessive fetal growth and intrapartum complications deriving from it. If ignored, impaired maternal glucose tolerance may become a major predisposing factor for neurological birth injuries. It appears therefore that with routine screening for diabetic predisposition and effective control of gestational diabetes the risk of fetal damage can be reduced substantially.
Intracavity optical parametric oscillator pumped by passively Q-switched Nd:YLF laser
Authors: Żendzian W. , Jabczyński J.K. , Kwiatkowski J.
Published: November 2008

We report on a passively Q-switched end pumped Nd:YLF laser including a noncritically phase-matched KTP singly resonant intracavity optical parametric oscillator (IOPO-KTP). For the Q-switching operation we have used Cr:YAG saturable absorber. The optimized passively Q-switched Nd:YLF laser without IOPO generated linearly polarized pulses of 11.5 ns and 1.07 mJ at 1047 nm. The conversion efficiency of the optimized Q-switched pulse energy at 1047 nm to 1547 nm of a signal approached about 47%. For optimizing both Nd:YLF laser and IOPO we have numerically solved a theoretical model. We have achieved 1.6-ns duration pulses at 1547 nm with energy of 0.5 mJ and peak power of above 300 kW. The beam quality was excellent (M2 ≈1).
Thalassemias and Other Hemoglobinopathies in Former Yugoslavia
Authors: Efremov G
Published: November 2008

Thalassemias and Other Hemoglobinopathies in Former Yugoslavia

This review summarizes our results on the epidemiology and molecular basis of thalassemias and other hemoglobinopathies in the republics and provinces of the Former Yugoslavia. Over the past 40 years, surveys of more than 37,000 school children and more than 1,600 adults, from all over Former Yugoslavia, except Slovenia, have shown an average incidence of β-thalassemia (β-thal) trait of 1.2%, ranging from 2.9% in the south (Macedonia) to 0.8% in the northwest (Croatia). The frequency of δβ-thal was 0.2%, while that of Swiss type hereditary persistence of fetal hemoglobin (HPFH) was 0.4%. Screening of 12,680 newborns has shown that the frequency of α-thal trait was 1.5%. The molecular basis of the thalassemias in the populations of Former Yugoslavia has been completely defined. More than 700 β-thal chromosomes have been studied and their molecular defect was determined. In the Macedonian population, 16 different β-thal mutations were detected, four of which (IVS-I-110, G→A; IVS-I-6, T>C; IVS-I-1, G>A and codon 39, C>T) accounted for 85% of all β-thal chromosomes. In the Croatian population, 18 different β-thal alleles were detected. Four new mutations [nucleotide (nt) -87, C>A; IVS-II-850, G>C; initiation codon mutation T>C; polyadenylation signal (poly A), AATAAA>AATGAA)] and one new deletion (1605 bp), were characterized. Molecular analyses of DNA from over 50 unrelated cases with δβ-thal have shown that this condition was mainly caused by a 13 kb deletion (Sicilian type); in one family, a deletion of >18 to 23 kb (Macedonian-Turkish type), and in another, a deletion of 148 kb (Yugoslavian type of εγδβ-thal) of the β-globin gene complex, were discovered. Molecular analyses of α-thal from Former Yugoslavia revealed the following defects: the -20.5, -17.5 and -3.7 kb deletions, a 5 nt deletion, and Hb Icaria [α142, Term→Lys (TAA>TCA in α2)]. The incidence of abnormal hemoglobins (Hbs) in Former Yugoslavia was 0.3%. Five different α chain variants in 16 families, 16 different β chain variants in 61 families, one δ chain variant in one family, two types of Hb Lepore in 122 families and two γ chain variants, have been characterized.
Molecular Analysis of Friedreich's Ataxia in Macedonian Patients
Authors: Kocheva S , Trivodalieva S , Vlaski-Jekic S , Kuturec M , Efremov G
Published: November 2008

Molecular Analysis of Friedreich's Ataxia in Macedonian Patients

Friedreich's ataxia (FRDA) is rare a progressive neurodegenerative disorder of autosomal recessive inheritance, which is associated with an unstable expansion of a GAA trinucleotide repeat in the first intron of the frataxin gene on chromosome 9q13. We have performed molecular analyses of the frataxin gene of 40 patients with spinocerebellar ataxia from the Republic of Macedonia. Fifteen had early onset of progressive ataxia (before the age of 25), while the remainder were over 25 years old at the time of diagnosis. Only 14 patients had a mutation in the frataxin gene and all of these had early onset ataxia. The number of GAA repeats was in the normal range in 50 healthy individuals.
Choleric Fictions: Epidemiology, Medical Authority, and An Enemy of the People
Authors: Matos Timothy Carlo
Published: November 2008

In its dramatic use of the emerging sciences of sanitation and prophylaxis, An Enemy of the People extends the medical field of Ghosts and other early plays to the triumphs and promises of the newly implemented germ theory that was transforming the medical and social landscape of disease. In its exploration of the culturally ascendant man of science, it addresses the communal and psychologically problematic dimensions of a missionary reformism in a society resistant to its demands.
Coercive Somatographies: X-rays, Hypnosis, and Stanislavsky's Production Plan forThe Seagull
Authors: Kairschner Shawn
Published: November 2008

This article explores points of contact between Stanislavsky's detailed 1898 mise en scène for the Moscow Art Theatre's production of Chekhov's The Seagull, on the one hand, and discursive practices – specifically X-ray photography and hypnosis – striving to map the vaguely perceptible interior spaces of bodies upon their visible surfaces, on the other. For each of these discourses, this act of mapping was dependant upon the work of an interpreting authority – the stage director, master hypnotist, or clinician – who penetrated, arrested, and forcefully rearticulated the meanings of the body's interior. The bodies of The Seagull's actors thus vividly conveyed not their own psychic material but that belonging to Stanislavsky, the intervening master interpreter. In this, they joined hypnotized hysterics and X-rayed patients in presenting a referential psychosomatic palimpsest, displaying at once a perceptible surface and a safely reordered and coercively reinscribed interior.
A Randomized Clinical Trial of Aquatic versus Land Exercise to Improve Balance, Function, and Quality of Life in Older Women with Osteoporosis
Authors: Arnold C.M. , Busch A.J. , Schachter C.L. , Harrison E.L. , Olszynski W.P.
Published: November 2008

Purpose: Despite the decreased gravitational loading that is experienced in an aquatic environment, little research has been conducted on this exercise medium for women with osteoporosis (OP). Aquatic exercise (AE) may improve function and balance, thus ultimately decreasing fall risk and the potential for hip fractures in this high-risk population.

Method: A total of 68 women with OP, aged 60 years or older, were recruited into a randomized clinical trial evaluating the impact of AE, land exercise (LE), and no exercise (NE) on balance, functional mobility, and quality of life (QOL).

Results: Only one balance measure (backward tandem walk) significantly improved with AE compared to LE, but this did not translate into a greater improvement in self-report function. There were no significant differences between the exercise interventions and NE, except for in ratings of global change, where participants in the AE group were three times more likely to report improvement than those in the NE group.

Conclusion: There were no differences in balance, function, or QOL in women with OP who followed an AE or LE programme compared to those in an NE control group. However, the significant differences in backward tandem walk between the AE and LE groups and self-reported global change between the AE and NE groups warrant further investigation. Significant improvements in balance and global change suggest that AE is a viable alternative for older women with OP who have difficulty exercising on land.
Scheduling Work Zones for Highway Maintenance Projects
Authors: Tang Yimin , Chien Steven I-Jy
Published: November 2008

Highway maintenance usually requires lane closures and disrupts traffic operations. Transportation agencies face increasing pressure to reduce construction time and alleviate the traffic impact. However, accelerated construction and compressed schedules are expensive. This study focuses on improving traffic operations and the efficiency of maintenance work through optimizing work zone schedules. The objective total cost, including agency and road user costs, is minimized while a discrete relationship between maintenance time and the associated cost is considered in the mix. A genetic algorithm is developed to solve the combinatorial, multidimensional optimization problem. A numerical example demonstrates the applicability of the developed model and efficiency of the solution methodology. A sensitivity analysis explores the relationships among decision variables.
Pavement Marking Retroreflectivity Inspection Data
Authors: Sathyanarayanan Sudhakar , Shankar Venky , Donnell Eric T.
Published: November 2008

Quantifiable life-cycle models of the service life of pavement markings are essential for a cost-efficient pavement marking management system. A study was conducted to develop an analysis procedure for typical pavement marking retroreflectivity inspection data. Retroreflectivity data collected by the National Transportation Product Evaluation Program on water-based paints in 2002 on a Pennsylvania test deck were used. Those data were considered interval-level duration data, and a Weibull analysis was performed. A Weibull analysis is a typical method in reliability engineering in which Weibull scale and shape parameters are estimated from failure data for making objective maintenance decisions. Results of the Weibull analysis indicated that the water-based paints had shape and scale parameters of 1.42 (±0.05), and 601.67 (±17.73) days, respectively, for skip line areas and 2.38 (±0.08) and 227.41 (±4.48) days, respectively, for left wheelpath areas. It was also determined that the probability of 2-year water-based paints lasting above 100 mcd/m2/lx varied from 0% to 27%. The lower limit corresponds to the left wheelpath, and the upper limit corresponds to the skip line area. The left wheelpath markings failed to stay above 100 mcd/m2/lx after approximately a year, while skip line markings could maintain 100 mcd/m2/lx ratings or higher for more than 1,000 days. White markings were found to last longer than yellow markings for the same exposure. This study used data from a single site in Pennsylvania. A multisite analysis accounting for time and space variations is recommended before adopting this method for minimum pavement marking retroreflectivity standard assessment.
Decision Tree for Pretreatments for Winter Maintenance
Authors: Russ Andrew , Mitchell Gayle F. , Richardson Wallace
Published: November 2008

This study addressed pretreatment protocol for winter maintenance of roadways using brine. Information on pretreatment was assessed from surveys of personnel in state departments of transportation and county garages in Ohio. Field durability studies of various applications of brine were conducted on portland cement concrete and asphalt concrete pavements in Ohio. Over three winter seasons, weather events and resulting pavement conditions were documented during pretreatment and during the subsequent events using visual assessment and limited road grip tester assessment. In addition, extensive laboratory studies were undertaken to supplement the field investigations. Integration of the findings resulted in a decision tree to aid in operational planning and pretreatment.
Relationship of Vertical Illuminance to Pedestrian Visibility in Crosswalks
Authors: Edwards Christopher J. , Gibbons Ronald B.
Published: November 2008

Twenty-six participants evaluated a series of crosswalk lighting designs by visually detecting objects at each crosswalk location while traveling in a moving vehicle. The research was performed on a closed test track under nighttime conditions while the participants were driving an SUV with regular halogen headlamps. The conditions included several vertical illuminance levels (6, 10, 20, and 30 lux), varied luminaire types [high-pressure sodium (HPS) and metal halide (MH)], and various target object types (pedestrian and surrogate objects). Only one age group of participants (66 years and older) was used for the study, with equal representation of males and females. The participants were asked to detect objects at each crosswalk location when they were confident an object was present. The results indicated that object detection distances changed on the basis of vertical illuminance level, luminaire type, and object type. Object detection distance for HPS was greatest at 30 vertical lux and for MH at 20 vertical lux. However, these results were moderated by the clothing color of the target object. When object color was considered, pedestrians in white clothing were identified earlier under the HPS lighting condition at 20 lux. Under the MH configuration, denim-clothed objects were detected earlier than black-clothed objects, especially at the 20-lux lighting level. The results suggest that a vertical illuminance level of 20 lux at crosswalk locations provides adequate levels for target object detection. In addition to benefiting from vertical illuminance, target objects that wore white clothing had detection distances superior to other object types of different clothing colors. Recommendations for crosswalk lighting configurations are further discussed.
Pavement Marking Retroreflectivity
Authors: Smadi Omar , Souleyrette Reginald R. , Ormand Daniel J. , Hawkins Neal
Published: November 2008

Previous research has shown that greater longitudinal pavement marking retroreflectivity levels increase drivers’ visibility and detection distance. However, increased visibility may cause drivers to feel too comfortable during nighttime conditions, and drivers may then pay less attention, operate their vehicles at unsafe speeds, or both. Before-and-after studies have been conducted on a pavement marking improvement such as repainting stripes or changing to a more durable marking material. Studies have also used models to estimate the retroreflectivity on the basis of the date of installation and vehicle exposure or have assumed a linear reduction in retroreflectivity over time. Only two studies have related field-measured pavement marking retroreflectivity to safety performance (crash data). One study analyzed the relationship between 3 years of pavement marking retroreflectivity data collected by the Iowa Department of Transportation on all state primary roads and corresponding crash and traffic data. The other study developed a spatial–temporal database by using measured retroreflectivity data to account for the deterioration of pavement markings over time, along with a statewide crash database to attempt to quantify a relationship between crashes and the quality (measured by retroreflectivity) of pavement marking. Three sets of data were analyzed: the complete database, records for two-lane roads, and records with retroreflectivity values less than or equal to 200 mcd/m2/lx only. The distributions and models of the entire database and the two-lane records did not show that poor pavement marking retroreflectivity correlated to a higher crash probability. However, when only records with retroreflectivity values of 200 mcd/m2/lx or less were examined, a statistically significant, albeit weak, relationship was determined.
Safety Evaluation of Flashing Beacons at Stop-Controlled Intersections
Authors: Srinivasan Raghavan , Carter Daniel , Persaud Bhagwant , Eccles Kimberly , Lyon Craig
Published: November 2008

FHWA organized a pooled fund study of 26 states to evaluate low-cost safety strategies as part of its strategic highway safety effort. One of the strategies chosen to be evaluated was the installation of flashing beacons at stop-controlled intersections. The intent of flashing beacons is to reduce the frequency of crashes related to driver unaware-ness of stop control. Geometric, traffic, and crash data were obtained at stop-controlled intersections for 64 sites in North Carolina and 42 sites in South Carolina. Empirical Bayes methods were incorporated in a before–after analysis to determine the safety effectiveness of installing flashing beacons while accounting for potential selection bias and regression-to-the-mean effects. Overall, installation of flashing beacons in North Carolina resulted in statistically significant reductions in total, angle, and injury-plus-fatal crashes. The intersections in South Carolina experienced little change following the introduction of flashing beacons, but the combined results from both states still indicated a statistically significant reduction in angle and injury-plus-fatal crashes. An economic analysis indicated that standard flashing beacons can achieve a 2:1 benefit–cost ratio.
Dual-Advisory Speed Signing on Freeway-to-Freeway Connectors in Texas
Authors: Voigt Anthony P. , Stevens Charles R. , Borchardt Darrell W.
Published: November 2008

This project recognizes the disparity in the relationship between truck and passenger car speeds and current advisory speed-signing practices. The results of this project provide a mechanism that traffic engineers may use to provide enhanced differential warning to trucks and passenger vehicles at freeway connector ramps. The strong evidence of a significant differential between the speeds that cars and heavy trucks can comfortably and safely traverse freeway connector ramps or loops revealed a need for further research. This research would investigate current advisory speed-signing practices and examine whether a dual-advisory speed-signing scheme, one that provides different recommended advisory speeds for trucks and passenger vehicles, can safely address this differential. On the basis of the results of the analysis of average and 85th-percentile speeds at the midpoint of each study curve, the dual-advisory warning signs had a positive impact on reducing speeds at the point of curvature on the curve and had an accompanying reduction in speed-related crashes at the study sites, or both.
Cost-Comparison Methodology for Selecting Appropriate Asphalt Concrete Mixes
Authors: McGhee Kevin K. , Clark Trenton M.
Published: November 2008

The Virginia Department of Transportation's (VDOT's) Road and Bridge Specifications combine with various special provisions to cover more than 13 asphalt concrete surface mix designations. Although the specifications offer recommendations about the types of mixes that should be programmed for a given set of facility characteristics, local conditions and experiences heavily influence the predominantly selected mix. As material prices continue to climb without budgets doing the same, local circumstances are more often going to contribute to the selection of the less expensive mixes, especially as long as managers lack a defensible rationale for specifying a more expensive option. This paper describes an economic analysis procedure designed to help engineers and managers select the most cost-effective mix. This procedure includes a methodology for estimating the expected service life for each mix, which is developed by using the systemwide condition ratings for all of Virginia's Interstate and state primary roads. Through the use of examples with typical project families, the research demonstrates that premium prices for stone matrix asphalt can generally be justified by better performance. In one illustration that uses actual condition and awarded price data, a life cycle cost analysis revealed that the use of stone matrix asphalt in lieu of dense-graded mixtures on Interstates might save VDOT more than $7,500 per lane mile in net-present-value costs.
Viscoelastic Behavior of Hydrated Lime-Modified Asphalt Matrix and Hot-Mix Asphalt under Moisture Damage Conditions
Authors: Khattak Mohammad J. , Kyatham Vikram
Published: November 2008

This paper characterizes the viscoelastic response of asphalt matrix (AM) and hot-mix asphalt (HMA) mixtures under dry and moisture-damaged conditions. The AM and HMA mixtures were made with two types of aggregates and one asphalt grade. The hydrated lime was used as a binder additive to reduce the moisture sensitivity of the mixtures. A dynamic shear rheometer was used to conduct frequency sweep and creep tests at various temperatures with AM specimens. The indirect tensile load test was conducted to characterize the creep response, tensile strength, elastic and plastic, and fatigue properties of the HMA mixtures. The results indicated that the generalized creep compliance mechanical model can effectively characterize the viscoelastic response of the AM and HMA mixtures under both wet and dry conditions. The AM testing demonstrated that the lime modification significantly improves the viscoelastic properties of the moisture-damaged AM. The fatigue life of the HMA mixtures improved because of the decrease in the rate of accumulation of tensile plastic deformation as a result of the addition of hydrated lime to the mixtures.
Anisotropic Behavior of Hot-Mix Asphalt at Low Temperatures
Authors: Wagoner Michael P. , Braham Andrew F.
Published: November 2008

A significant cause of premature pavement deterioration can be attributed to the initiation and propagation of cracks. Hot-mix asphalt (HMA) is thought to be an anisotropic material in which the sample orientation with respect to compaction should be considered when laboratory tests are conducted. The sample orientation could be an important factor for fracture testing of HMA because crack paths are influenced by aggregates. Previous research on the anisotropic nature of HMA has mainly focused on bulk material properties at high temperatures. This research investigated the anisotropic effect of low temperatures for bulk material and separation properties. These two properties were analyzed for samples compacted with the Superpave® gyratory compactor and cored field samples with both vertical and horizontal orientations. Three mixtures were tested for complex modulus, creep compliance, tensile strength, and fracture energy. It was determined that orientation influenced the complex modulus and creep compliance results for these three mixtures. Statistical analysis conducted on the tensile strength test results determined that the mean values were similar. The results from the fracture energy tests did not prove consistent, as there were no clear trends between the three mixtures and the specimen fabrication method.
Analysis of Hot-Mix Asphalt Lab Compactability Using Lab Compaction Parameters and Mix Characteristics
Authors: Leiva Fabricio , West Randy C.
Published: November 2008

The compactability of hot-mix asphalt (HMA) mixtures is often used to describe how easy or difficult it is to compact a mixture on a roadway. Several asphalt researchers have proposed the use of laboratory-measured parameters for mixtures and their components as indicators of HMA compactability and resistance to permanent deformation. In this study, laboratory parameters used to represent field compactability of HMA mixtures, such as the compaction energy index and Bailey method ratios, were compared with the compaction slope, the locking point, and the number of gyrations required to reach 92% of the theoretical maximum specific gravity. Once the relationships among these parameters were established, basic mix parameters such as gradation, aggregate shapes, binder grade, and mix volumetric properties were used to explain why some mixtures are more compactable than others in the gyratory compactor. The results suggested that any of the parameters mentioned above can be used to describe compactability in the laboratory. Gradation type, aggregate type, and aggregate size were the most significant variables that can be used to explain the compactability of specimens compacted with the Superpave® gyratory compactor.
Tennessee Environmental Procedures Manual
Authors: Skinner Nancy T. , Delaney Douglas J.
Published: November 2008

In 2002 the Environmental Division of the Tennessee Department of Transportation (TDOT) initiated a simple update of its written environmental procedures for projects evaluated under the National Environmental Policy Act (NEPA). In 2003 a new governor and a new TDOT commissioner ushered in changes to the planning, environmental, and public involvement responsibilities of TDOT. As a result of these leadership changes, the manual's simple update was redirected to a more broadly based assessment of the department's existing environmental procedures and the creation of a more streamlined environmental review process that is better integrated into TDOT's project development process and more transparent to the public and other stakeholders. During this time, TDOT also created its first official policy for environmental reviews of state-funded transportation projects, an environmental procedures manual. The manual incorporates the new environmental review processes required by the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU) and the pending Tennessee Environmental Streamlining Agreement. This case study describes the manual's development, highlights reforms in the department's philosophy and approach that have affected the contents of the manual, and shares lessons learned. The 2007 Tennessee Environmental Procedures Manual (TEPM), available on TDOT's website, will be useful to other states updating their own older manuals or creating new manuals to meet the requirements of SAFETEA-LU. The TEPM provides a handy reference for navigating the NEPA process, implementing the SAFETEA-LU environmental review requirements, and standardizing technical analysis and documentation that should be of value to NEPA practitioners and transportation professionals in Tennessee and across the country.
Comparative Evaluation of Infrastructure Strategies to Reduce Emissions from Intermodal Freight Movement in Southern California
Authors: Ang-Olson Jeffrey , Facanha Cristiano
Published: November 2008

Five major infrastructure projects are evaluated that could substantially reduce emissions from intermodal goods movement in Southern California: on-dock railroad expansion, near-dock railroad expansion, mainline railroad capacity expansion and grade separation, electrification of the Alameda Corridor, and electrification of the entire mainline regional railroad system. Given the importance of Southern California as a gateway for international trade, the need for expansion of the capacity of the region's goods movement system, and the contribution of goods movement to the region's serious air quality problems, it is important to understand the emissions impacts of major goods movement infrastructure projects. This study finds that all five infrastructure projects can reduce a significant amount of emissions. Electrification of the entire mainline railroad system would achieve by far the largest emission reductions, eliminating emissions of more than 7,500 tons of nitrogen oxides (NOx) and 236 tons of particulate matter with a diameter of 2.5 μm or smaller (PM2.5) annually. Mainline capacity expansion would achieve the next-largest reductions. Alameda Corridor electrification is the most cost-effective of the five strategies at $9,000 per ton of NOx and $304,000 per ton of PM2.5.
Comparison of Real-World Emissions of B20 Biodiesel versus Petroleum Diesel for Selected Nonroad Vehicles and Engine Tiers
Authors: Frey H. Christopher , Rasdorf William , Kim Kangwook , Pang Shih-hao , Lewis Phil
Published: November 2008

Field data for in-use fuel consumption and emission rates were collected for 15 nonroad vehicles by using a portable emission measurement system. Five backhoes, four front-end loaders, and six motor graders were tested once on petroleum diesel and once on B20 biodiesel. The vehicles represented a variety of engine certification tiers. A methodology was developed for study design, field data collection, data screening and quality assurance, data analysis, and benchmarking of the data. On average, 6.9% of data were lost because of quality issues and more than 3 h of valid data were collected in each test. Time-based emission factors increased monotonically with respect to engine manifold absolute pressure. Fuel-based emission factors were sensitive to differences between operations of engines idling and not idling. Typical duty cycles were quantified in terms of frequency distributions of manifold absolute pressure and used to estimate cycle average emission factors. On average, the use of B20 instead of petroleum diesel led to an insignificant 1.8% decrease in the nitric oxide (NO) emission rate and significant decreases of 18%, 26%, and 25% for opacity, hydrocarbons (HC), and carbon monoxide (CO), respectively. Emission rates decreased significantly in newer, higher-tier vehicles compared with older ones. Fuel use, NO, HC, and CO data were of similar magnitude as independent benchmark data. Specific recommendations were made for future work.
Comparative Field Evaluation of Biodiesel Impact on Hot Stabilized Emissions from School Buses
Authors: Farzaneh Mohamadreza , Zietsman Josias , Perkinson Dennis , Spillane Debbie
Published: November 2008

This study investigated the impact of biodiesel (B20: 20% biodiesel, 80% conventional diesel), cruise speed, and average acceleration rates on emissions of oxides of nitrogen (NOx), hydrocarbons (HC), carbon monoxide (CO), and carbon dioxide (CO2) from diesel school buses. Two drive cycles were developed on the basis of the rural and urban drive cycle data collected with Global Positioning System technology. Five buses were selected according to the current model year mix in Texas and were driven following the developed drive cycles for three different fuels (TxLED, B20 market blend, and B20 all soy). The emission data were collected by using a portable emission measurement system. The data were aggregated to represent the current Texas school bus fleet mix and rural versus urban miles driven. The results of statistical analysis showed that use of B20 had no significant effect on the level of NOx and CO2 emissions by the school buses. However, it was found that the biodiesel resulted in a significant decrease of HC and an increase in CO emissions. Similarly, the effects of cruise speed and acceleration rates on pollution showed differences depending on the pollutant in question. Some recommendations for emission control plans can be drawn from the analysis.
Predicting On-Road Particle Number Concentrations of Light-Duty Gasoline Vehicles from Gas Concentrations with Time-Series Cross-Section Regression
Authors: Qu Yingge , Holmén Britt A. , Ravishanker Nalini
Published: November 2008

There is a need to quantify real-world particle number emissions from light-duty gasoline vehicles (LDGVs) because of the known toxic properties of ultrafine and nanoparticles, the large number of LDGVs on the road, and the lack of field measurements of particle number (not mass) emissions during real-world vehicle operation. Onboard tailpipe gas and particle number concentrations and vehicle operating data were collected second by second with an instrumented 1999 Toyota minivan driven multiple times on a 17-mi test route by 22 drivers. Time-series cross-section regression analysis was applied to individual test runs to develop a suitable model for predicting particle number concentration based on gaseous pollutant concentrations and sampling conditions. The results indicate that particle number concentration can be effectively predicted from gas concentrations, ambient air temperature and relative humidity, and exhaust temperature. The model signifies the physical relationships between particle number and gas concentrations with respect to gas-to-particle formation processes and implies the possibility of future use of existing gaseous pollutant concentration databases for particle number prediction from a wider range of vehicles.
Acoustical Absorption of Porous Pavement
Authors: Nelson James T. , Kohler Erwin , Öngel Aybike , Rymer Bruce
Published: November 2008

Acoustical absorption coefficients of more than 140 pavement cores were obtained by the impedance tube method with two microphones and cross-spectral analyses. The effectiveness of the impedance tube in predicting noise reduction for different mixes was evaluated by comparing the correlations between onboard sound intensity levels and absorption. Theoretical predictions of acoustical absorption due to friction between air and porous matrix and thermal relaxation were compared with measured results for an idealized porous structure. The model was used to infer porosity, tortuosity, and pore size from measured acoustical absorption spectra for manufactured porous asphalt and extrapolate test results to nonnormal angles of incidence, assuming isotropy of the porous structure. This model will help improve mix designs to increase the absorption of pavement surfaces and can be used to estimate porous pavement properties.
Framework for Environmental Assessment of Tire–Pavement Noise
Authors: Hajek Jerry J. , Blaney Chris T. , Hein David K.
Published: November 2008

Traditionally, the objective of tire–pavement noise studies has been limited to ranking of different pavement surfaces in terms of their potential to generate noise. The potential to generate noise has been assessed by using a variety of sound-level measurements and sound-level measures, typically quite different from those used for the environmental assessment of highway noise. A fundamental methodology is described for the assessment of tire–pavement noise that fits the existing framework for the environmental assessment of highway noise. In this context, it is necessary (a) to express the differences in tire–pavement noise in terms of the sound-level units used for the environmental assessment of highway noise and (b) to consider a realistic situation that includes, for example, sound levels emitted by the entire traffic flow at locations that correspond to outdoor recreational areas of residential dwellings. The process is illustrated by applying it to the environmental assessment of freeway noise in Ontario, Canada, involving two pavement surface types: a dense-graded asphalt concrete surface and a portland cement concrete surface. The results indicate that the difference in sound levels between the two surface types at a residential location adjacent to a freeway can reach up to about 2 or 3 dB(A) Leq (24 h). However, when the typical highway geometry is considered, the presence of noise barriers, and a typical car–truck freeway traffic mix, this difference is reduced to less than 1 dB(A) Leq (24 h). This difference is typically interpreted as having an insignificant environmental impact.
Linking the National Environmental Policy Act and Planning
Authors: Geiselbrecht Tina Collier , Meaux Michelle
Published: November 2008

A case study of the efforts of a metropolitan planning organization to link the National Environmental Policy Act (NEPA) and the planning process is presented. The Capital Area Metropolitan Planning Organization (CAMPO) in Texas initiated a series of workshops to begin a dialogue with agencies not typically involved in long-range planning. CAMPO brought together resource and regulatory agencies, nontraditional stakeholders such as members of the Save Our Springs Alliance, the state department of transportation, and others for a meaningful dialogue that resulted in greater understanding among all parties. The workshops led to a sharing of data that can be used in developing long-range transportation plans. Areas of environmental sensitivity as well as cultural and historic features are now being mapped and used in preparing a long-range transportation plan. The next steps will build on the efforts of the early workshops to continue the exchange of data and information and work cooperatively to link the planning process with the NEPA process. It is anticipated that this early information exchange will result in improved project delivery.
Dynamics in Behavioral Response to Fuel-Cell Vehicle Fleet and Hydrogen Fueling Infrastructure
Authors: Shaheen Susan A. , Martin Elliot , Lipman Timothy E.
Published: November 2008

Transportation is a major contributor of carbon dioxide and other greenhouse gas emissions from human activity. It accounts for approximately 14% of total anthropogenic emissions globally and about 27% in the United States. Growing concern regarding the impacts of climate change and greenhouse gas emissions, along with petroleum dependence and energy security, has led to innovations in automotive and fuel technology. However, the behavioral response to the newest transportation technologies, such as hydrogen fuel-cell vehicles (FCVs) and fueling infrastructure, is not well understood. The results of an exploratory hydrogen FCV fleet study, which focused on fleet drivers’ attitudes and perceptions over a 7-month period in 2006, are examined. The study employed a longitudinal survey design, with three phases and one focus group. There were limitations to the exploratory data set generated from this study (e.g., small sample size, self-selection bias, and generalizability). However, the results provided insights into participants’ responses to the FCV and hydrogen fueling infrastructure over time and could help to inform further inquiry. Higher levels of hydrogen exposure were correlated with increased comfort with hydrogen, especially among those who were less experienced. Early adopters of the technology generally felt safer driving the FCV than later adopters. Respondents mostly felt safe refueling the FCV. As experience with the FCV increased, participants felt increasingly safe with the vehicles. The driving range was considered a limitation. Furthermore, over the course of the study, participant perception of vehicle range increased because of learning.
Vehicles and E85 Stations Needed to Achieve Ethanol Goals
Authors: Greene David L.
Published: November 2008

An analysis of the number of stations and vehicles necessary to achieve future goals for sales of ethanol fuel (E85) is presented. Issues related to the supply of ethanol, which may turn out to be of even greater concern, are not analyzed here. A model of consumers’ decisions to purchase E85 versus gasoline based on prices, availability, and refueling frequency is derived, and preliminary results for 2010, 2017, and 2030 consistent with the president's 2007 biofuels program goals are presented. A limited sensitivity analysis is carried out to indicate key uncertainties in the trade-off between the number of stations and fuels. The analysis indicates that to meet a 2017 goal of 26 billion gallons of E85 sold, on the order of 30% to 80% of all stations may need to offer E85 and that 125 to 200 million flexible-fuel vehicles (FFVs) may need to be on the road, even if oil prices remain high. These conclusions are tentative for three reasons: there is considerable uncertainty about key parameter values, such as the price elasticity of choice between E85 and gasoline; the future prices of E85 and gasoline are uncertain; and the method of analysis used is highly aggregated—it does not consider the potential benefits of regional strategies or the possible existence of market segments predisposed to purchase E85. Nonetheless, the preliminary results indicate that the 2017 biofuels program goals are ambitious and will require a massive effort to produce enough FFVs and ensure widespread availability of E85.
Results of Micro-Deval Test for Coarse Aggregates from Virginia Sources
Authors: Hossain M. Shabbir , Lane D. Stephen , Schmidt Benjamin N.
Published: November 2008

Aggregate is the most widely used construction material, and a key aspect of aggregate quality is durability. In this study, the Micro-Deval test was studied to evaluate its suitability for assessing the durability of coarse aggregates from Virginia sources. Results obtained with the Micro-Deval test and several commonly used aggregate tests were compared. The Micro-Deval test showed a very high potential to evaluate aggregate durability with better precision than did the conventional tests. It was able to differentiate between good- and poorly-performing aggregates at least 70% of the time and was able to identify the quality difference between similar aggregate types with varying degrees of weathering. Thus, the Micro-Deval test is recommended for use as a quality control tool for aggregate assessment to supplement the current measures of aggregate quality.
Determining the Length of the Right-Turn Lane at a Signalized Intersection
Authors: Kikuchi Shinya , Kronprasert Nopadon
Published: November 2008

This paper develops the analytical and computational processes for determining the length of the right-turn lane at a signalized intersection. It examines the factors that influence the length, reviews the available literature and practices, derives the recommended length analytically, develops a set of tables of the recommended lane lengths as a function of the approach volumes (right-turn, through-traffic, and cross-traffic volumes) and signal timing, and discusses the results. The analysis is done for two cases: when right-turn-on-red (RTOR) is not permitted and when it is permitted. The probabilities of the following events are computed: the right-turn vehicles do not overflow to the through lane and block the movement of through vehicles, and the queued through vehicles do not block the entrance of the right-turn lane. The lengths are derived to keep these probabilities greater than a threshold value. The recommended length is shown in the number of vehicle spaces, and a procedure that converts this number to the actual distance is presented. The current guidelines for lane length are based on the arrival rate of right-turn vehicles only. The arrival rate of the through vehicles must be considered also. As a result, the proposed lane length is different than in the existing guidelines. In addition, a new guideline of lane length is developed for the RTOR case.