bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Prospective Skiing Injury Study
Authors: Hauser W 
Published: December 2008

A two-year comprehensive prospective experimental skiing injury study is presented. All skiers of two randomly chosen groups registered data of every skier day including injuries, inadvertent releases, hours of skiing, and falls.
The main objective of this study was to estimate the risk difference in skiers with a correct binding setting compared to the average binding setting in a normal skiing population. Also, the risk difference between normal ski poles with a special grip design regarding injury risk to the skier's thumb was investigated.
Nearly 18 000 skier/days were registered. Risk data regarding severe injuries show a similar range as in controlled clinical studies. In this prospective study, however, the bypass effect of unreported injuries can be avoided. Therefore, the overall injury rate including those injuries perceived by the skier as being nonsevere skiing injuries is distinctly higher. Among such injuries is the “skier's thumb” rupture of the ulnar collateral ligament of the metacarpophalangeal joint. Analyzing the injury pattern of this study shows that the most frequent injury is the “skier's thumb.”
Furthermore, many aspects of skier behavior can be shown with this study. The number of falls related to skiing ability and skiing performance and the rate of injuries per falls are reported.
The experimental design can show a distinctly lower risk of injury to skiers with proper binding settings compared to the control group. The risk of lower extremity equipment-related (LEER) injuries is about 3.5-fold lower with the properly adjusted ski bindings compared to the average binding setting we find today on ski slopes. The difference in the risk is caused by a distinct reduction of knee injuries.
Cruciate Ligament Injuries in Female Alpine Ski Racers
Authors: Ellman BR , Holmes EM , Jordan J , McCarty P 
Published: December 2008

In recent years, more and more articles in the literature have documented female athletic injuries, especially knee injuries and, in particular, injuries to the anterior cruciate ligament. It has become obvious that this injury is a particularly serious one. A number of explanations have been given for this increased incidence. One obvious difference in recent years has been the more aggressive approach to athletics by the female participant.
To see whether female alpine ski racers were having a greater percentage of anterior cruciate ligament injuries, a study was developed in conjunction with the Vermont Alpine Racing Association (VARA). A questionnaire was sent to all VARA alpine racers during the summer of 1985, asking for information about ski injuries, training, mechanism of injuries, and treatment. The questionnaire included a release from the skier for information from treating physicians. In addition, coaches were sent printouts of responses, so that further responses and information could be obtained.
Out of approximately 600 racers, 196 Vermont alpine ski racers responded to the questionnaire. Of these, 135 respondees were male and 61 were female. Thirty-three male racers (twenty-five percent) reported knee injuries, but only four (three percent) reported cruciate ligament injuries. This correlated fairly closely with the percentages that have been reported for male basketball players. Twenty-three female racers (thirty-eight percent) reported knee injuries. This was not a remarkable difference from the male racers' percentage of knee injuries. Significantly, however, eleven (18%) of the females responding had cruciate ligament injuries, which was six times the incidence of their male counterparts. Almost one out of every five serious alpine female ski racers were reporting serious knee injuries that included anterior cruciate ligament tears!
This study has revealed a significantly higher incidence of serious knee injuries in female versus male ski racers. Because this fairly large group of skiers is well controlled as far as site of skiing (Vermont), level of expertise (all expert skiers), and equipment (essentially all have state-of-the art skis, bindings and boots), this observation appears to be significant. The most serious of the knee injuries is the anterior cruciate tear, and this was prevalent in females to males in a 6:1 ratio. Further study would seem to be merited to discover the cause of this difference, whether it be muscle strength, knee geometry, or equipment. Certainly, the concept of preventive bracing must be considered if this incidence of serious knee injuries continues or increases.
Concepts of Underground Corrosion
Authors: Escalante E 
Published: December 2008

Corrosion in soil is a complex phenomenon, but there are some basic concepts that are useful in understanding the process. Underground corrosion is electrochemical in character, and this fact is used to describe the corrosion process in terms of an ordinary dry cell. The differences between corrosion in disturbed and undisturbed soil are discussed, and data are presented to emphasize these differences.
The results reveal that soil composition is less important than soil resistivity, but both are subordinate in importance to oxygen availability. Thus, corrosion is negligible in undisturbed soils where oxygen concentration is low.
Backcalculation of Pavement Layer Properties
Authors: Lytton RL 
Published: December 2008

This was prepared for the symposium as a state-of-the-art paper. The paper summarizes the history and present use of nondestructive testing (NDT) and speculates on future developments and uses of NDT in backcalculating pavement layer properties. The paper concentrates on the backcalculation of the elastic stiffness of pavement layers.
Measurement methods include a variety of methods of applying loads to the pavement and a number of sensors of the pavement response. Loading methods include static or slowly moving loads, vibration, near field impulse, and wave propagation which applies to far field measurements. A fundamental distinction is drawn between near field impulse loads which closely simulate traffic loads and far field impulse loads, the results of which must be corrected substantially to provide realistic pavement layer moduli.
Analysis methods are surveyed, including some historical methods, microcomputer methods, impulse and response analysis methods, and systems identification methods. The historical methods include two-layer closed form and graphical methods, equivalent layer methods, and a closed-form multilayered method that searches for the best set of moduli to satisfy a leastsquares criterion. Microcomputer methods are described generically, noting all of their common features, including methods of dealing with both random and systematic errors in measuring and computing layer moduli. Random errors can be reduced by repeating the measurements. Systematic errors include the assumptions used in the backcalculation process, including nonlinearity. The results of an exercise conducted to estimate the size of systematic errors is reported. Impulse and response methods analyze the complete signals to determine a “transfer function” of the pavement from which the complex moduli of the layers can be backcalculated. Some speculation is offered on how this information may be used to determine fatigue and permanent deformation properties of pavement layers. A systems identification method of analyzing far field measurements is illustrated.
Uses of nondestructive testing in the future are envisioned to include layer thickness, asphalt or water content, density, elastic stiffness, creep compliance, fracture, and permanent deformation properties. A strategic objective of NDT methods is for them to become the primary method of measuring pavement material properties.
The Multidepth Deflectometer (MDD) System for Determining the Effective Elastic Moduli of Pavement Layers
Authors: De Beer M , Horak E , Visser AT 
Published: December 2008

This paper describes a nondestructive pavement testing system called the multidepth deflectometer (MDD), which is used to measure depth deflection profiles of pavements. Effective elastic moduli of multilayered pavement structures can be backcalculated from these measurements. This system was developed in South Africa during the late 1970s to enhance the extensive program of full-scale accelerated testing with the aid of the heavy vehicle simulator (HVS).
The MDD consists of a series of up to six linear voltage differential transducers (LVDTs) installed vertically into the pavement at preselected depths in a relatively small-diameter hole. Normally the MDDs are anchored at a depth of approximately 2 m below the surface of the pavement. Resilient depth deflections are measured with the MDD in association with a moving load.
Case studies of measured deflections and backcalculated effective elastic moduli are given for tests on an asphalt base, a granular base, a cemented base, and a concrete base pavement section. The results are interpreted and discussed in terms of the behavioral characteristics and pavement responses, including permanent deformations. It was found that: 1. Asphalt bases may become granular after extensive accelerated testing. 2. Crushed stone bases may become stronger as a result of trafficking. 3. Lightly cemented bases crush near the surface, thus weakening the layer. 4. One concrete pavement debonded from its subbase after 190 000 load repetitions.
Application of Ground-Penetrating Radar and Infrared Thermography to Pavement Evaluation
Authors: Holt FB , Eckrose RA 
Published: December 2008

New technologies have enabled the pavement engineer to develop a better picture of the pavement structure. Two of these new technologies are ground-penetrating radar and infrared thermography. Each of these techniques allows the pavement engineer to nondestructively evaluate subsurface defects within and under the pavement. Infrared thermography is now widely used to determine the location of delaminations within the pavement.
In the case of delaminations or debonded sections of pavement, the thin delaminated area will heat faster than the adjacent thicker section, and the infrared scanner will detect temperature differences between the two areas. This process is widely used to inspect bridge decks. It is used to determine the extent of deterioration beneath asphalt overlays on the deck and thus save the costs of removal of the asphalt and any waterproofing membrane.
Ground-penetrating radar can be used to determine a number of characteristics useful to the pavement engineer in developing a rehabilitation scheme. Radar is used to determine the condition of joints in concrete pavement, to locate and size voids beneath the pavement, to determine the thickness of pavement, and to determine the composition of the pavement structure.
Case histories are presented to discuss each of these technologies and their applications. These technologies are presently being written into ASTM standards for particular applications, including determination of delamination using infrared thermography and determination of pavement layer thickness using ground-penetrating radar. Limitations in the use of the techniques are also discussed.
Deflection Reading Accuracy and Layer Thickness Accuracy in Backcalculation of Pavement Layer Moduli
Authors: Irwin LH , Yang WS , Stubstad RN 
Published: December 2008

Accurate deflection readings must be obtained when using NDT devices in order to obtain correct backcalculated layer moduli. This paper provides an analysis of the sources of deflection errors and illustrates through a series of examples how random deflection errors and random pavement thickness errors affect backcalculated moduli.
The consequence of these errors is most pronounced in the backcalculated modulus of the surface course. The moduli of the base and subbase layers are also affected, and the subgrade moduli are only slightly affected by these errors. To some degree this outcome may be due to the bottom-to-top approach used by the backcalculation program MODCOMP 2.
The consequence of the variability of the backcalculated moduli on the required pavement overlay thicknesses was found to be minimal. This was due to the fact that, generally speaking, data errors which cause an overestimate of the base course modulus also cause an approximately equally significant, but opposite, underestimation of the surface course modulus. Thus, the needed overlay requirement remains nearly the same.
The paper shows how certain FWD calibration and testing procedures can be used to minimize deflection measurement errors. The accuracy of backcalculated moduli is shown to be determinable from the RMS error of the deflection fit. The examples provide an impression of the extent to which random layer thickness errors and deflection measurement errors will influence the ability to discern point-to-point variability of layer moduli for the specific pavement structure considered in this investigation. This provides a perspective from which the practical accuracy of the backcalculation approach can be judged.
A Performance Comparison of Selected Backcalculation Computer Programs
Authors: Mahoney JP , Coetzee NF , Stubstad RN , Lee SW 
Published: December 2008

This paper provides an overview of six different techniques which were used to estimate the “elastic modulus” of five pavement sites located in Washington State. Five of the techniques were backcalculation computer programs and the remaining one was laboratory-determined moduli (diametral and triaxial). Further, these sets of derived moduli were used to assess the needed overlay thickness (for a fixed traffic level) for each technique.
A comparison of the moduli results revealed more “agreement” than “disagreement.” Overall, the overlay thicknesses were, in general, quite similar with a few exceptions. Further, a number of factors were presented which may have contributed to some of the differences.
Numerical and Optimization Techniques Applied to Surface Waves for Backcalculation of Layer Moduli
Authors: Hossain MM , Drnevich VP 
Published: December 2008

This paper eontains two methods of determining the pavement moduli and thicknesses using a computer prograrri written in FORTRAN 77. The first method, a simple finite difference technique, is developed for the analysis of generalized Rayleigh waves in multilayered elastic media. The method, which leads to an eigenvalue problem, is very effective in determining theoretical dispersion curves for pavement systems modeled as layered composite plates with free surfaces at both top and bottom or free surface of the top and rigid base at the bottom. Backcalculation of moduli and thicknesses is done by an optimization routine developed by Powell [1] based on least squares criterion.
The second method determines a theoretical dispersion curve based on Knopoff s technique [2]. Since phase velocities of the waves observed experimentally on pavement structures are complex, suitable modification of Knopoff's algorithm for the geologic model has been made by the authors to account for this effect. For optimization, the same technique is used as mentioned above.
Numerical results obtained in the two cases show excellent agreement with previously published solutions obtained by other theories.
Soil Reinforcement Design Using Geotextiles and Geogrids
Authors: Bonaparte R , Holtz RD , Giroud JP 
Published: December 2008

This paper provides an overview of the design of soil structures reinforced with polymeric materials. Applications for soil reinforcement are reviewed and categorized according to the type of soil structure, type of load, and function and location of reinforcement. Approaches to design are reviewed, and it is shown that most current design procedures are based on simple extensions of classical limit equilibrium analyses.
Properties of polymeric reinforcement relevant to design are presented. They are subdivided into tensile properties and soil-reinforcement interaction properties. Use of wide-strip, constant-load creep tests are recommended for evaluation of tensile properties for design of permanent soil structures. Soil-reinforcement interaction characteristics are evaluated in terms of direct sliding of soil over reinforcement and pullout of reinforcement from soil. Direct sliding characteristics should be evaluated using the direct shear test. Pullout characteristics for geotextiles can be approximated from direct shear test results; however, pullout characteristics for geogrids must be evaluated using pullout tests.
The paper concludes with a detailed presentation of simple limit equilibrium design analyses for three of the most commonly encountered types of reinforced soil structures: reinforced slopes, reinforced soil walls, and reinforced embankments over weak foundations. Specific recommendations are made on determination of reinforcement properties for design of these three types of structures.
A Process for Solidifying Sodium Nitrate Waste in Polyethylene
Authors: Heiser JH , Franz E-M , Colombo P 
Published: December 2008

A laboratory-scale process has been developed for the solidification of nitrate salt wastes in polyethylene. The process uses a commercially available single-screw extruder which continuously discharges prescribed polyethylene-waste mixtures from the hoppers to the output die, where it is extruded into a container while still in the molten form. The molten mixture (̃110 to 120°C) conforms to the shape of the container and solidifies upon cooling. Proportional feeders maintain waste-to-binder ratio and homogeneity of the waste form. Present studies use dry wastes, although wet solid wastes can be processed using vented extruders of the type used for the bitumen solidification process.
Tests were performed to determine leachability and mechanical stability. Emphasis is placed upon leaching of nitrates from the waste forms. Leach tests were performed according to ANS 16.1 as well as the EPA extraction procedure (EP). For polyethylene waste forms containing 30 to 70 weight percent sodium nitrate, ANS 16.1 leach indices range from 11 to 7.8, respectively. Compressive yield strengths range from 18 to 5 MPa (after 90 days' water immersion). The results of the EP indicate that the nitrate release levels for waste forms containing as much as 70 weight % sodium nitrate are not defined as characteristically hazardous waste.
Differential scanning calorimetry (DSC) was used to confirm the compatability of polyethylene and simulated salt wastes at elevated temperatures. Components of the polyethylene/sodium nitrate system, alone and in combination, were tested by DSC at temperatures to 400°C. At these temperatures, no chemical interactions were observed between polyethylene and nitrate waste compositions.
Evaluating the Freeze-Thaw Durability of Portland Cement-Stabilized-Solidified Heavy Metal Waste Using Acoustic Measurements
Authors: El-Korchi T , Gress D , Baldwin K , Bishop P 
Published: December 2008

The use of stress wave propagation to assess freeze-thaw resistance of portland cement solidified /stabilized waste is presented. The stress wave technique is sensitive to the internal structure of the specimens and would detect structural deterioration independent of weight loss or visual observations.
The freeze-thaw resistance of a cement-solidified cadmium waste and a control was evaluated. The control and cadmium wastes both showed poor freeze-thaw resistance. However, the addition of cadmium and seawater curing increased the resistance to more cycles of freezing and thawing. This is attributed to microstructural changes.
A Physical Testing Program for Stabilized Metal Hydroxide Sludges
Authors: Forslund BL , Smith LJS , Bergstrom WR 
Published: December 2008

A proposed method of closing two Resource Conservation and Recovery Act surface impoundments containing metal hydroxide (F006) sludges involved stabilization and on-site disposal. A sample testing program was developed as part of an evaluation of processes offered by various firms interested in performing the stabilization. For this application, the stabilized material was to have sufficient strength to support construction and cover loads, low permeability, long-term durability, and low settlement under anticipated loads.
The test procedures developed to determine those properties were based on standard soil and soil-cement test methods to the extent possible. The standard test methods proposed for use included the ASTM Test Methods for Unconfined Compressive Strength of Cohesive Soil (D 2166), for One-Dimensional Consolidation Properties of Soils (D 2435), Wetting-and-Drying Tests of Compacted Soil/Cement Mixtures (D 559), and Freezing-and-Thawing Tests of Compacted Soil/Cement Mixtures (D 560). A falling-head test was used to determine the coefficient of permeability. Appropriate molds and specimen preparation procedures were sent to each firm with a sample of the raw sludge in order that the stabilized sludge specimens would be prepared in the same manner.
Modifications to the proposed test procedures were required due to the condition of several sets of samples. The procedures for evaluating the freeze-thaw and wet-dry durability were altered by eliminating the brushing and weighing of samples between cycles. This sample handling was eliminated so that the relative effects of environmental exposure could be more readily compared. A few of the samples suffered significant expansion, shrinkage, cracking or some combination of these to a degree that made them unusable.
In general, the specimen preparation procedures and test methods developed worked well for the stabilized sludge samples. The unconfined compressive strength test results were highly variable and ranged from 0.5 kg/cm2 (100 lb/ft2) to over 35 kg/cm2 (70 000 lb/ft2). The compressibility under a load of 1.5 kg/cm2 (3000 lb/ft2) ranged from 0.5% to 5%. The permeability of the stabilized material was generally low and in the range of 10-6 to 10-7 cm/s. The specimens generally withstood more freeze/thaw cycles than wet/dry cycles; several of the specimens lost much of their strength and integrity upon saturation. No strong correlation between any of the physical properties was observed. However, specimens which included cement as an additive tended to fail at low strain, have higher unconfined compressive strength, and were less compressible.