bluuebunny/crossref_metadata_2025 huggingface dataset:
The Crisis in Response Training
Authors: Kaufmann S
Published: December 2008

The need for training of first responders, contractors, government agencies, and insurance companies to use chemical dispersants effectively is demonstrated by the loss of opportunities both to reduce cleanup costs and to gain helpful data in evaluating the advantages of using dispersants. The interest shown in a new method of training in the use of chemical countermeasures emphasizes the need to be prepared to use them on actual spills as they occur.
A Computer-Assisted Planning System for Oil Spill Response Chemical Applications
Authors: Shafer RV
Published: December 2008

The microcomputer is a very useful oilspill response tool: It can help the spill contingency planner organize and present a wide variety of information; it can help the spill response trainer create realistic scenarios and models of spill events; and it can help the spill response operations manager optimize operational decisions and expedite a variety of communications. This paper suggests some specific ways microcomputers can help plan for and respond to oil spills, and it focuses on a computer program written to help expedite operational decisions and optimize operations for the chemical dispersion of spilled oil in Alaskan waters.
Field Measurement of Effectiveness: Historical Review and Examination of Analytical Methods
Authors: Fingas MF
Published: December 2008

Data are provided on 106 separate offshore experimental spills to determine dispersant field effectiveness. Effectiveness ratings for 25 of these spills were assigned by the experimenters; they vary from 0 to 100% and have an average of 33%.

Measurement techniques used for these experiments are reviewed and described. The techniques include: subsurface measurements to determine oil in the water column, surface sampling to determine oil remaining, dispersant application amount or distribution, and the use of remote sensing to observe visually the results or to quantify the area of surface oil. Existing means of detection and quantification appear to be effective.

Most experimenters have used subsurface oil data in an attempt to establish a mass balance and thereby an effectiveness value. This technique is critically examined using values from historical trials, and it is shown that the subsurface oil does not have a regular distribution in relation to the surface slick. Correlation cannot be established between concentrations at depth or with time and distance. This lack of correlation implies that mass balance values based on subsurface oil concentrations in relation to the surface slick are not reliable. Effectiveness results claimed in the literature are also suspect because they do not correlate well with the maximum oil concentration seen at a given depth.

The mathematical relationships used to provide the integrated amount of oil in the water column are also examined. It is shown by simulation that effectiveness claimed is highly sensitive to both assumptions and mathematical treatment. Historical data are used to show that effectiveness values can vary over an order of magnitude depending on the algorithm used. Values in the literature are generally the highest one would obtain using reasonable algorithms.

A number of phenomena have been observed at spill sites. Herding of oil occurs immediately after dispersant application and has sometimes been misinterpreted as dispersion.

Examinations of spills where slicks were monitored for longer than 3 h show that extensive resurfacing of oil occurred. Resurfacing is particularly problematic because, depending on current and wind, resurfacing may occur outside slick boundaries. When this occurs, resurfaced oil is not included in subsequent calculations, and consequently, effectiveness is overestimated.

Field effectiveness cannot be reliably determined by using only measurements of oil in the water column. The distribution of oil in the water column is not known nor does it necessarily bear a relationship to surface slick boundaries. Furthermore, in the initial hours—perhaps as many as 7—the oil concentration in the water column may be transitory as significant amounts of oil resurface. Remote sensing over a long term such as two or three days is suggested as the primary technique for monitoring experimental spills and for attempting to establish a mass balance.
Mechanics and Micromechanics of Fatigue Crack Propagation
Authors: Tanaka K
Published: December 2008

The present paper reviews major developments in mechanics and micromechanics of fatigue crack propagation at an ambient temperature over the past two decades, and suggests directions of future developments. Mechanics of plastic deformation and closure of fatigue cracks under cyclic loading will first be presented, then the propagation behavior of long and short cracks will be described. Emphasis will be placed on the experimental as well as the theoretical aspects of the mechanical treatment of fatigue crack propagation.
Test Approach for Dense Slurry Erosion
Authors: Roco MC , Nair P , Addie GR
Published: December 2008

The paper presents two test devices to simulate erosion wear by friction and by impact in dense slurry flow. The empirical coefficients determined experimentally are introduced in a predictive model, which numerically simulates the wear by directional impact of solid particles, random impact, and coulombic friction. The last two components are specific for high concentrated slurries (C ≳ 5 to 10% by volume).

The device for erosion by friction has a moving frame with a fast oscillating motion in a horizontal plane. The layer of abrasive particles slides on the bottom side, where the exposed specimens are located. Tests performed with alumina and sand particles are discussed.

The directional and random impacts are both simulated on an inclined wall, which divides into two parts a confined jet of suspension. The experimental results are illustrated for four worn materials under the impingement of a sand-water slurry stream.

The equivalence between the energy dissipated by particles-wall interactions and erosion intensity gives a unified way to determine all erosion components. The suggested test devices provide the coefficients of proportionality. The approach can be used for the dense slurry flows usually encountered in industrial applications, for various flow regimes and wall geometries.
Considerations for Fiber Sampling with Infrared Microspectroscopy
Authors: Bartick EG
Published: December 2008

The sampling of fibers by infrared microspectroscopy is considered. Fibers are grouped into three categories: 30 to 50 µm diameter, less than 30 µm diameter, and small clumps of fibers. In the first type, rapid analysis can be easily accomplished without any preparation; however, the effects of the circular cross section of the fibers must be considered. In the second type, the best results are obtained by flattening the fibers. In the third type, the most reproducible results are acquired by pressing the clump into a potassium bromide substrate. When doing spectral subtraction, all categories require that the mixture and the subtracted spectra are obtained under the same sampling conditions. When applying these considerations to the analysis of fibers, microscopy combined with infrared (IR) spectroscopy should prove to be a very viable analytical method.
Collision Injuries in Alpine Skiing
Authors: Lystad H
Published: December 2008

A controlled study of collision injuries in Hemsedal, Norway, is presented. Accident data for 1982 through 1986 seasons were analyzed. A total of 883 injured skiers and 379 controls were compared for epidemiological data.

Eighteen percent (n = 158) of the injuries were due to collision. There was a great difference in collision injury rate during the recording time. A peak injury rate of 0.27/1000 skier days in 1984 when a new chairlift doubled the lift capacity without opening any new slopes declined to 0.11/ 1000 skier days in 1986 after making new slopes and widening old ones.

Beginners and children were more at risk, and 28% of the injured by collision suffered a head injury.

In conclusion, different degrees of difficulty of the slopes give a better separation between the different skiing-ability groups, and wider slopes reduce relatively the “collision zone” at the tree/ slope border. This results in safer skiing on each slope.
Reliability Testing of Seven Nondestructive Pavement Testing Devices
Authors: Bentsen RA , Nazarian S , Harrison JA
Published: December 2008

Nondestructive pavement testing devices produce and collect deflection data using methods unique to each device. Loadings are produced on various-sized loaded areas by vibratory motions of various loads and frequencies and also by dropping masses from various heights. Deflections are measured using various types of deflection sensors.

Data from three vibratory loading and four falling weight loading nondestructive pavement testing devices are evaluated and compared for accuracy, reliability, and repeatability. The loading output of each device is compared to the output of a load cell placed under the loaded area. The output of the deflection gauges at varied load levels is compared to the output from both a linear variable differential transformer placed under the gauge and a transducer placed next to the gauge. The repeatability of each device to produce consistent and accurate data at one location on various pavement types is determined by loading that location many times in a short period of time. The long-term repeatability of each device is determined by loading a specific location many times over a long period of time. Conclusions are drawn for each device concerning its reliability for producing accurate loading and deflection output and its repeatability for producing accurate results over time.
Backcalculation of Layer Moduli from Nondestructive Pavement Deflection Data Using the Expert System Approach
Authors: Chou YJ , Uzan J , Lytton RL
Published: December 2008

None of the existing backcalculation procedures is guaranteed to give a reasonable, effective elastic layer modulus for every deflection basin measured. The differences of results among various backcalculation programs are magnified by the differences of distinct analysts using the same program but applying different input parameters. A more experienced analyst often may obtain better results. Some of the difficulties, such as the deviation of pavement material properties from the linear elastic, isotropic, and homogeneous assumptions, the uncertainty of input parameters (for example, the deflection measurement), and the limitation of basin matching techniques, may only be dealt with by informed engineering judgement. A knowledge-based expert system approach as described in this paper may be used to generate more consistent and better estimations of in situ pavement material properties by combining numerical computations with a pavement expert's knowledge and judgement. A knowledge base which serves as an intelligent pre- and postprocessor to the backcalculation program is developed. The knowledge base may be revised easily as better understanding emerges.
ILLI-PAVE Based NDT Analysis Procedures
Authors: Thompson MR
Published: December 2008

ILLI-PAVE (a stress-dependent, finite-element pavement model)-based procedures have been developed for flexible pavement analysis and design. Full-depth asphalt concrete (AC), AC granular base, and AC high-strength stabilized base (HSSB) type pavements can be considered. Pertinent ILLI-PAVE inputs are the moduli of the AC and stabilized base layers and ERi (the stress-dependent subgrade resilient modulus).

ILLI-PAVE data bases were used to develop direct plot procedures and algorithms for backcalculatirtg pavement layer and subgrade moduli from falling weight deflectometer (FWD) type nondestructive testing (NDT) data. FWD 9-kip surface deflection basin measurements (at 0, 12, 24, and 36-in. offsets) and AREA (a calculated deflection basin parameter) are the required plot and/or algorithm inputs.
Stress Dependency of the (Sand) Subgrade Modulus by the Dead Weight of the Pavement Layers: Field Experiments with the Falling Weight Deflectometer
Authors: Pronk AC
Published: December 2008

In the Netherlands nearly all pavements for motorways and highways can be modelled into a three-layer system: 1. A wearing and base course of asphalt concrete. 2. A Base of (un)bound material. 3. A subbase and subgrade of sand.

In situ deflection measurements can be used for the backcalculation of the moduli of the separate pavement layers including the subgrade. Sand is an unbound granular material, and therefore its modulus ought to be stress dependent. This dependency is rarely noticed when falling weight deflection (FWD) measurements are carried out on a pavement at different force levels. Also, within the measurement on the asphalt surfacing (I) of the sections at issue, no changes were obtained in the backcalculated subgrade moduli when the applied FWD load was varied. However, when the wearing course and base course had been removed carefully, a significant decrease was noticed in the backcalculated subgrade moduli from the FWD measurement carried out on the bound base (II) compared to the values gained from the measurement on the asphalt surfacing (I). But when the load was varied again no significant changes were observed in the backcalculated moduli. The decrease in the subgrade moduli of Measurement I and Measurement II can be explained by assuming a stress dependency for the subgrade modulus. The difference in the subgrade modulus found in both measurements is caused by the difference in the dead weight of the overlaying construction layers. The problem is that this stress dependency will not be found when the load is varied and a backcalculation procedure is used which is based on curve fitting.

An explanation is given why this stress dependency of the subgrade modulus will be overlooked in the backcalculation procedure of FWD measurements at different force levels. Also, a backcalculation procedure is proposed, using a simple model for the stress-dependent character of the subgrade modulus, in which the road can still be considered as a linear elastic multilayer system.
SHRP Plans for Nondestructive Deflection Testing in the Development of Pavement Performance Prediction Models
Authors: Richter CA , Rauhut JB
Published: December 2008

Nondestructive deflection testing using falling weight deflectometers is one element of the monitoring effort planned by the Strategic Highway Research Program (SHRP) for the Long-Term Pavement Performance Studies (LTPP). Nondestructive deflection testing provides data for the backcalculation of moduli for the various pavement structural layers, as well as critically important data on material variability that is expected to be an important independent variable in future pavement performance prediction models. The backcalculated layer moduli are critical to the development of calibrated mechanistic-empirical models for a variety of uses. These moduli must be calculated using standard procedures representing the state of the art. Current studies are aimed at identifying specific problems leading to unacceptable variations in backcalculated moduli when using different computer codes and closure tolerances. It is expected that these studies will provide a wealth of information which will be useful as SHRP planning for the use of deflection testing proceeds. Backcalculated moduli from measurements at a number of locations within a test section are to be used to establish the mean, minimum, maximum, and standard deviation of moduli for each layer. In addition, it is planned that four drop heights will be used to apply four different load levels at a single location. Four load levels should provide the variations in layer moduli with stress sensitivity.

Presently it is planned to use nondestructive testing to study variations in deflections and moduli on a seasonal basis, especially variations through the spring thaw in northern climates. These studies should provide critically important information that has been a severe limiting factor in past attempts to predict the performance of pavements subjected to spring thaw conditions. While major damage occurs to pavements during the spring thaw, these conditions have never been adequately accounted for on a mechanistic basis.

This paper summarizes current (as of Spring 1988) SHRP planning for the utilization of nondestructive deflection testing in their Long-Term Pavement Performance Studies. The plans presented herein are preliminary. It is hoped that this presentation will generate comments as well as constructive criticism, which might be incorporated into SHRP plans before work has progressed to a point where changes are difficult to make.
Superheavy Overloads: NDT Pavement Deflections Compared to Predictions Based on Backcalculated Moduli
Authors: Nokes WA
Published: December 2008

Effects on in-service pavements from superheavy overloads exceeding 9 340 kN were investigated by field study and mechanistic modeling. Field study consisted of conducting a crack survey, measuring pavement deflections using a Dynaflect before and after hauling the overloads, and using three nondestructive testing (NDT) instruments to measure surface deflection when the overloads were hauled. In addition, field study included measuring static wheel loads and extracting cores. Prior to hauling, deflections were predicted using elastic layer computer models for assumed “best” and “worst” case scenarios. These initial predictions are compared to measured in-transit seismometer deflections. Layer moduli later were backcalculated using the BISDEF computer model and Dynaflect data. Results of crack surveys show no change in visible condition of the pavement after transporting the overloads. Dynaflect measurements after transport were approximately equal to pavement deflections measured before hauling the overloads. In-transit deflection measurements show that a “big basin” results from widely distributed trailer axle loads. Deflections from tractor tires were not substantially different from those caused by trailer tires. Measured in-transit deflection is less than the “best” and “worst”case initial predictions. Subsequent backcalculation yielded a wide range of layer moduli. However, these moduli resulted in final estimated deflections that are much closer than initial predictions to field measurements.
Technical Overview on Mechanical and Physical Property Measurements on Coatings
Authors: Di Bari GA
Published: December 2008

Measurement of the mechanical and physical properties of metallic and inorganic coatings presents difficulties. The difficulties arise because coatings are often thin, and they are by definition attached to substrates. The expediency of separating the coating from its substrate to measure certain characteristics may be resorted to. Although this technique may provide useful information, a doubt may linger as to whether the coatings on a particular batch of production parts have identical properties as those measured on separately prepared specimens. The coating may present handling problems even when it is detached if it is brittle and extemely thin. The properties may be dependent on thickness; studying the properties of thick coatings to deduce the properties of thinner ones may not be worthwhile.
Crack Growth and Fracture of Continuous Fiber Metal Matrix Composites: Analysis and Experiments
Authors: Goree JG , Dharani LR , Jones WF
Published: December 2008

It is reasonably well accepted that the standard procedures developed for isotropic homogeneous metals using linear elastic fracture mechanics models are not appropriate for either continuously or discontinuously reinforced metal matrix composites. For example, the ASTM plane strain fracture toughness test methods typically give widely different values of fracture toughness depending on the particular test specimen geometry as well as the fiber orientation. For unidirectional boron/aluminum composites one finds approximately a factor of two difference between the measured values of fracture toughness obtained from a center-notched test coupon and that given by a compact tension specimen. In particular for unidirectional composites, and to a slightly lesser degree for angle ply laminates, the dominant controlling mechanism for this behavior is matrix plasticity. A secondary toughening mechanism, resulting from the matrix plasticity, is stable transverse fiber failure. The present paper will focus on both the influence of the large plastic zone at the end of the notch and on the constraint that the fibers impose on the shape of this zone, as well as the transverse crack growth. First, a review of some particular experimental studies and methods of analysis for predicting crack growth and fracture of notched unidirectional metal matrix composites is given. Next, two mechanistic models for unidirectional composites with damage are presented. The first is an improved shear lag model that accounts for both of the above damage modes, and the second describes a recent extension of the shear lag concept in an attempt to include transverse stresses. A related finite width laminate model is then discussed, and it is indicated that an isotropic finite width correction factor is reasonably accurate for most center-notched test coupons.
Systematic Approach for the Design of Pumpable, Cement-Based Grouts for Immobilization of Hazardous Wastes
Authors: Sams TL , Gilliam TM
Published: December 2008

Cement-based grouts have proven to be an economical and environmentally acceptable means of waste disposal. Costs can be reduced if the grout is pumped to the disposal site. This paper presents a systematic approach to guide the development of pumpable grouts.
Characterization and Control of Solidified Radioactive Wastes According to the Italian Rules: Organization of a Characterization Facility and First Results
Authors: Ricci GA , Donato A
Published: December 2008

According to Technical Guide No. 26, officially published in 1987 by the Italian Regulatory Body (ENEA-DISP), the radioactive wastes are now classified in Italy in accordance with the identities and the concentrations of radionuclides, no distinction being made from the point of view of the physical state.

Three “radwaste” categories have been established: The first refers to wastes that decay below exemption limits for free discharge, as defined by current Italian laws, within a few months or within a few years, maximum. The second category of radwastes, which is the most important in terms of overall production, refers to those wastes whose radioactivity decays to radioactive levels comparable with the exemption limits set up for natural radioactive solids within a few centuries, maximum. The radwastes falling into this second category, which are generated mainly by nuclear power plants, must be solidified by means of suitable solidification agents such as cement, bitumen, or polymers. Moreover, a test program must be performed to assure the compliance of the waste forms with a set of specified waste form characteristics.

The third category of radwastes refers to the high-activity liquids arising from the first cycle of the fuel reprocessing facilities and to the alpha-bearing wastes.

The tests to be applied for the characteristics control of real radioactive solidified wastes of the second category are briefly described. They require, in some cases, that a noncommercial apparatus be operated in radiation-controlled areas. A glove-box chain, also suitable for the characterization of solidified alpha wastes, has been designed and built.

The first characterization test campaign has been carried out on radwastes produced by boiling water reactor power plants solidified in cement and the results are presented.
Leaching Low-Level Radioactive Waste in Simulated Disposal Conditions
Authors: Buckley LP , Tosello NB , Woods BL
Published: December 2008

Leaching tests formally recognized by the International Atomic Energy Agency (IAEA) or by the American Nuclear Society (ANS) are used to evaluate the release of radioactivity from a waste form under idealized conditions. These conditions do not represent the reality of disposal environments, where engineered barriers are in place to limit access of water and to retard the migration of radionuclides into the biosphere. A test program underway at Chalk River, Ontario is attempting to provide an understanding of the release and transport of radionuclides under more realistic conditions. Preliminary results indicate that releases are suppressed by at least an order of magnitude when the effects of barriers in a repository failure are considered. However, migration mechanisms cannot be fully explained by classical concepts involving saturated flow. Research effort is now focused on measurements in an unsaturated, reducing environment, the condition which will be expected to be found in a well-designed repository.
Using Hydrated Lime to Control Erosion of Dispersive Clays
Authors: McElroy CH
Published: December 2008

Laboratory testing and actual field observations over the past 15 years have shown that 1 to 4% of hydrated lime has been successful in controlling erosion of highly dispersive clays. The modified pinhole test procedure has been used to determine the amount of hydrated lime needed. Dispersive clays are highly erosive because they contain a higher percentage of dissolved sodium in their pore water than ordinary clays. The colloids go into suspension in practically still water. Dispersive clays behave as individual particles instead of aggregates or as a mass. They are not easily detectable by the usual tests performed in a geotechnical laboratory. The pinhole test has proven to be a valuable aid in identifying dispersive clay soils. In the pinhole test, dispersive clays are classified as D-1 or D-2. Nondispersive clays are classified as ND-1 or ND-2. ND-3 and ND-4 classes are borderline. Field sampling, specimen preparation, test procedures, construction methods, field performance, and monitoring are discussed.
The Canadian Standards Association and the Evolution of Head and Face Protection in Canadian Hockey
Authors: Dixon JL
Published: December 2008

The Canadian Standards Association (CSA) is Canada's foremost and best-known standards development, certification, testing, and inspection organization. CSA has published over 1300 standards in 8 major areas. About one third of these standards are referenced in legislation. Standards benefit society in many ways. They provide protection, guide purchasing, enhance interchangeability, compatibility, and reliability, and they have many other advantages.

The development of a standard involves committees, public reviews, consumer group reviews, and other activities.

In 1959, the need for quality hockey helmets was identified. Their design improved over the years, particularly in terms of impact attenuation. The first CSA standard was published in 1975. Many improvements in the standard have been made since then.

In 1973, the need for quality hockey face protectors was identified, and a CSA standard was published in 1978 to address this need.

Since the inception of these CSA standards, eye injuries and blind eyes have been dramatically reduced. All players who suffered eye injuries and blinded eyes had not worn CSA-certified face protectors.

In 1979, the need for international standards on protective equipment for hockey was identified. The first ISO/TC83/SC5 meeting was held in Ottawa, Canada, where the first drafts of hockey helmet and face protector standards were completed. The second meeting was held during August 1988 in Helsinki, Finland, and the third meeting was held in Stockholm, Sweden, during April 1989. International Organization for Standardization (ISO) standards are expected to be published in 1991–1992.

Facially-featured headforms have been developed to test hockey helmets and face protectors accurately.

Testing, certification, inspections, audits, and investigations are also services provided by CSA in support of their standards work.

The institution of standards followed by the certification of products have proven to be effective in reducing sports injuries.
The Development of Head, Face, and Neck Protectors for Ice Hockey Players
Authors: Odelgard B
Published: December 2008

In 1963, the Swedish Ice Hockey Association introduced the compulsory use of helmets for ice hockey players in matches sanctioned by the association. As such, the first rules were formulated for testing and certifying helmets. As a step in the association's efforts to reduce injuries to players, separate rules were also drawn up for the protection of the eyes, the teeth, and the whole face. It is now recognized that injuries to players have been reduced both in number and severity, despite a great increase in the number of hours of play. This positive result has been achieved both by the injury-prevention qualities of the protector and by extended compulsory use of combined protectors (helmets and face protectors) and, more recently, by the use of a throat protector. The development of head protectors during the last 25 years has been interesting and has been concerned with design, production, material, test methods and equipment, and so forth. There is no doubt that the hockey helmets have lead the way for other types of sport and recreational helmets. A study of the history of ice hockey helmets provides a good example of how rules and standards may guide the development of design and performance. All ice hockey players in Sweden who play in official matches are covered by group insurance. Therefore, the statistical data on injuries can be considered reliable.
Effect of Aggregates on Performance of Bituminous Concrete
Authors: Brown ER , McRae JL , Crawley AB
Published: December 2008

Because aggregate comprises approximately 95% of asphalt mixtures, it has a major effect on the performance of mixtures. The quality of filler and amount of filler greatly affect asphalt concrete performance. To insure satisfactory performance, procedures must be available that can be used to detect poor-quality mixtures and there must be techniques available for improving mixture properties.

The objective of this paper is to present data from various studies that show the effect of aggregate grading on performance of asphalt mixtures. Test methods to evaluate these mixture properties are discussed.

A well-graded, crushed aggregate should be used to provide the highest-quality asphalt concrete. Uncrushed aggregates such as natural sands and uncrushed gravels produce mixtures with lower stability and decreased durability, whereas a well-graded aggregate fits together more tightly during compaction, resulting in a lower required asphalt content and improved stability and durability.

The maximum aggregate size is important to control stability, skid resistance, and compactibility of the mixture. A larger maximum size aggregate produces a higher stability and usually requires less asphalt content. The larger size aggregate also provides for improved skid resistance. Compaction of thin layers is difficult when the maximum aggregate size is too small. The compacted lift thickness should be at least twice the maximum aggregate size.

The amount of mineral filler in a mixture greatly affects the overall mix quality. Since the filler tends to fill the voids in the mineral aggregates, an increase in filler results in a corresponding decrease in optimum asphalt content. Laboratory test results also indicate that a mixture design performed for an aggregate with higher filler content will result in a significantly higher stability than that for lower filler content. The type of filler used also affects the mixture properties.

The quality of the aggregate must be controlled to insure a quality asphalt concrete. Some properties that must be considered are maximum aggregate size, amount of crushed particles, and amount and quality of filler.
Rutting, Asphalt Mix-Design, and Proposed Test Road in Saudi Arabia
Authors: Lee KW , Al-Dhalaan MA
Published: December 2008

The drastic change in traffic characteristics due to a crash development program in Saudi Arabia has introduced new forms of pavement distresses. Rutting, which was virtually absent ten years ago, became the principal distress mode. A feasibility study was performed on the Dhahran-Abqaiq road, which is experiencing a severe rutting problem, to formulate rehabilitation alternatives. The comparative study indicates that the Hveem mix-design method gives relatively lower optimum binder content than the Marshall mix-design method and that some of the potential reasons for the rutting at the Dhahran-Abqaiq road were overasphalting, fine-graded mix, and poor quality control. In addition, test results indicate that a sulfur-extended-asphalt mixture can be utilized for reducing the rutting problem, since it provided higher stability values. Finally, to help solve the widespread rutting problem in Saudi Arabia, a decision was made to include test sections in the rehabilitation program of this road.
Measuring the Susceptibility of Emulsion Based Seal Coats to Debonding
Authors: Selim AA , Heidari NA
Published: December 2008

Asphalt mixes, hot and cold, can experience bond loss due to moisture damage, a phenomenon called “debonding” or “stripping.” Debonding in hot mixes has been given more attention by researchers than debonding in cold mixes and seal coats, and there has been no documented methodology to quantify bond loss in seal coats. This report contains a description of a newly developed laboratory test experiment called Seal Coat Debonding Test (SDT) to examine the extent of seal coat susceptibility to moisture damage.

When the test was performed on several emulsion based seal-coat specimens, with asphalt emulsion binder, the nature of the outcome strongly suggested dividing seal coats into three categories according to their degree of vulnerability (DV) to moisture damage. Highly vulnerable seal coats are those that experience a loss of aggregate of more than 20% (based on the weight of the base bitumen and the totally intact aggregate). Moderately vulnerable seal coats lose more than 10% and up to 20%, and low vulnerable seal coats lose up to 10%.

The test is relatively easy to conduct and is considered unique in the sense that no similar tests are currently in use to quantify the amount of bond loss in seal coats. The test is applicable only to seal coats using asphalt emulsion as a binder.
Load-Frequency Effect on Fatigue Life of IMP6/APC-2 Thermoplastic Composite Laminates
Authors: Dan-Jumbo E , Zhou SG , Sun CT
Published: December 2008

Load-frequency effect on fatigue life of a thermoplastic and toughened BMI composite was investigated. Experimental results were obtained using three frequencies at two load levels with three types of laminates, each containing a center hole. Besides fatigue life, the temperature history near the hole and the specimen stiffness were monitored. In addition, the hysteresis loop was recorded at various stages of the fatigue test to observe the variation in viscoelastic property of the specimen. From the fatigue test results, it was found that fatigue life of matrix-dominated thermoplastic composite laminates decreased as load frequency increased. This behavior is opposite to that of epoxy-based fiber composites. For fiber-dominated thermoplastic laminates under tension-compression load, very low load-frequencies (less than 0.4 Hz) could significantly lower their fatigue life. Analytical models were developed to account for the load-frequency effect on fatigue life of thermoplastic composites. Temperature rise near the hole was included in the model to account for temperature effect.
Characterization of Impact Damage Development in Graphite/Epoxy Laminates
Authors: Masters JE
Published: December 2008

Experimental investigations indicate that the damage tolerance of graphite/epoxy systems, as measured by the laminate's residual compression strength after low-velocity impact, is directly proportional to the neat resins strain to failure. Results also indicate that laminate damage tolerance is significantly increased when thin, discrete layers of tough, ductile resin are “interlayered” or placed between the graphite/epoxy lamina. The physical mechanics which lead to this improved impact resistance are examined in this investigation. Interlayered and noninterlayered 36-ply pseudoisotropic [(±45/0/90/0/90)2/±45/0/90/±45]s laminates were subjected to low-velocity, drop-weight impacts. Incident impact energy levels ranged from 1110 to 8890 N · m/m of laminate thickness (that is 250 to 2000 in. · lb/in. (Note: Original measurements were in English, which appear in parentheses in this paper.) The resulting impact-induced damage was characterized by a combination of destructive and non-destructive test methods, including ultrasonic C-scan, light microscopy, and scanning electron microscopy. The differences in the amounts and in the distributions of impact-induced damage in the interlayered and noninterlayered laminates will be discussed in detail. The ultrasonic C-scan data indicate that interlayering significantly reduced the size of internal delamination at all impact energy levels. Microscopic investigation of sectioned, polished impact specimens indicates that the pattern of damage development was also altered through interleafing. Although transverse cracks developed in the interlayered laminates at intermediate impact levels, they do not form delaminations at the ply interfaces as they do in the uninterleafed laminates. Damage at these levels is limited, for the most part, to a system of transverse cracks. While interlayered laminates do delaminate at the high-impact energy levels, the number and size of the delaminations are reduced.
Environmental Effects in the Atmospheric Corrosion of Zinc
Authors: Cramer S , Carter JP , Linstrom PJ , Flinn DR
Published: December 2008

The Bureau of Mines, U.S. Department of the Interior, as part of the National Acid Precipitation Assessment Program, is conducting a field exposure program to measure the corrosion damage on commonly used structural metals and the incremental effects of acidic deposition and other environmental variables. Corrosion damage, air quality, rain chemistry, and meteorology are being continuously measured at five sites in the Eastern and Midwest United States for periods up to 84 months. Corrosion damage on zinc for periods up to 36 months was determined from weight-loss measurements, analysis of corrosion film chemistry, and of precipitation runoff chemistry. The results suggest the long-term zinc corrosion film consists of a stable inner layer sensitive to atmospheric sulfur dioxide (SO2) concentrations and a nonprotective outer layer. A synergistic reaction involving SO2 and nitrogen dioxide (NO2) may occur. Dry deposition of SO2 and NOx on the corrosion film is substantial. Zinc losses from the corrosion film are proportional to hydrogen ion loading. Covariance between many air quality and rain chemistry variables may be low enough to avoid, to a considerable degree, problems in developing linear regression models of corrosion damage.
Using the Classification of Corrosivity of Atmospheres to Extend the Service Life of Materials, Structures, and Products
Authors: Vrobel L , Knotkova D
Published: December 2008

The resistance of products to atmospheric degradation is an important quality consideration. In Czechoslovakia, corrosion protection is considered to be an integral element of quality. The corrosion protection system is verified after each production step. The quality of the corrosion protection system is also confirmed by authorized state and departmental testing laboratories. Commissions of large industries concerned with atmospheric effects provide consultation and expert advice, especially in the application of international, national, and departmental standards and regulation.

The assurance of product corrosion resistance is an integral part of the quality control process. A system of coordinated standards covering general principles regulates construction, design, selection of materials, and protection systems. Emphasis is placed on the standardization of quality testing methods. Department and industry standards are now being developed. The physical and chemical principles of corrosion are incorporated in the approach used in these standards.

Every product is exposed to the atmosphere, either during manufacture or during its service life. The atmospheric environment varies from place to place and moment to moment. To select corrosion protection measures rationally for construction materials, it is necessary to know how the various atmospheric factors affect materials and the protective systems that are used with them. The generalization of this knowledge regarding the kinetics of the degradation of materials and protective systems, with information on the influence of the atmospheric factors, permits a practical classification system for atmospheric corrosivity to be developed. The essence of this classification system has been incorporated in national and international standards.

Active international cooperation among twelve member nations has allowed the International Standards Organization Technical Committee 156, Working Group 4 to produce four draft standards. This work summarizes many years of independent effort by the members.

The technique of classification of the corrosivity of the atmosphere is useful in making maps showing the corrosivity distribution for regions. It is also helpful in the detailed mapping of localities with variations in pollution levels. This approach is also used to select optimum corrosion protection measures and to develop testing procedures for products exposed to the atmosphere.
Corrosion Monitoring of Shipboard Environments
Authors: Agarwala VS
Published: December 2008

A corrosion monitoring system is developed to determine the corrosivity of naval environments. It consists of a sensor (dissimilar bimetallic couples) and a galvanic current recording system (zero resistance ammeter). The data recording equipment is designed to monitor shipboard environments continuously on a long-term basis. Initially, a database was created from these sensors using accelerated laboratory environmental chambers. Corrosion monitor data, recorded on naval ships and aircraft carriers during their deployment at sea, are analyzed and assessed with respect to the laboratory database. The results show a direct relationship between the sensor output and the corrosivity of the constituents present in the environment.
A New Method to Monitor In-Situ Protective Properties of Rust on Weathering Steel
Authors: Ito S , Kihira H , Murata T
Published: December 2008

To evaluate how protective rust is, and to understand the role rust plays, electrochemical impedance of the rust films on low alloy steels, particularly weathering steels, was studied in a sodium sulfate (Na2SO4) solution. By the analysis of the harmonic current, the impedance in the frequency range of 1 Hz to 1.0 kHz is considered to be due to the ion transfer resistance through the rust film, which is dominant factor for the protective properties of the rust films. Based on this principle, a compact instrument was developed to monitor the protective properties of the rust films formed on weathering steels of field structures.
Characteristics of an Electrostatically Charged Air-Atomized Spray for Pesticide Application
Authors: Simmons HC , Lehtinen JR
Published: December 2008

This paper describes a series of tests performed to evaluate the characteristics of a new system that produces electrostatically charged sprays. The system consists of a nozzle (code-named ENS) that uses air to atomize liquid pesticide into a fine spray which is simultaneously electrostatically charged and a power converter unit which supplies a 1000-V output from a 12-V battery input.

The nozzle is specifically designed for water-based pesticides applied at low flow rates on the order of 75 mL/min (1.2 gal/h). The liquid is supplied at a nominal pressure of 103 kPa (15 psig) and the atomizing air is supplied at the same nominal pressure, resulting in approximately equivalent mass flow rates for liquid and air.

The nozzle produces very fine spray quality, typically giving mean drop sizes of 15 μm both with and without the use of electrostatic charging; thus the latter can be considered an optional operating feature. Measurement of the charge/mass ratio is fundamental to understanding the behavior of electrostatically charged sprays, so considerable attention was paid to designing a satisfactory and reproducible method of making the measurement. The results showed that considerable variation in the apparent value of charge/mass ratio can occur using differing methods and at different positions relative to the spray nozzle. Consistent values on the order of 1 to 3 mC/kg were eventually obtained, however, using a Faraday cage. An endurance test of 170 h indicated no change in any characteristic.

A study was made also of the liquid flux resulting from the spray pattern produced, for both moving and non-moving targets.

Finally, a short investigation was made using four liquids having compositions typical of various pesticide carriers to determine their effect on the behavior of the ENS spray nozzle. The results were encouraging as they showed only minor differences.
Plasma Etching of Aluminum Alloys in BCL3/CL2 Plasmas
Authors: Chen C-H , DeOrnellas S , Burke B
Published: December 2008

Aluminum etching in BCl3/CL2 plasmas is characterized by studying the etch rate of aluminum and native aluminum oxide films as functions of reactant flow rates and rf power in a parallel plate plasma etcher. Results indicate that the etch rate is primarlly dependent upon the Cl2 concentration and is only slightly dependent upon the rf power used to sustain the discharge. Several additives are used to achieve the high resolution and anisotropic pattern required for aluminum alloys. Parametric studies support the roles of the additives have been made.
Application of Total Reflection X-Ray Fluorescence Analysis for Metallic Trace Impurities on Silicon Wafer Surfaces
Authors: Eichinger P , Rath HJ , Schwenke H
Published: December 2008

Total Reflection X-Ray Fluorescence Analysis (TXRF) is presented as a new analytical tool which allows to assess the metal contamination on silicon wafer surfaces in a non-destructive way. The technique uses a conventional X-Ray tube with a Mo anode, an energy-dispersive Si(Li) spectrometer, and an alignment set-up for the exact control of the angle of incidence which is kept below the critical angle for total reflection. Detection limits in the order of 100 ppm of a monoatomic layer are achieved e.g. for transistion metals. Application studies include plating of metals from a high purity liquid process chemical (BHF) and the adsorptivity of the silicon surface for Br originating from RCA type cleaning procedures.