bluuebunny/crossref_metadata_2025_split huggingface dataset:
Microbiological Contamination of Fuels During Storage
Authors: Littmann ES 
Published: March 2009

Microorganism growth during hydrocarbon storage is a well-recognized problem. The most easily detected problem is fuel filter plugging, particularly in aviation fuels. Other problems include degradation of hydrocarbon quality, corrosion of storage tanks, and concentration of hazardous or toxic growth by-products in the water associated with the storage.
Particular problems and the growth of the microorganisms creating them are discussed. The discussion also includes methods for detection and quantitation of the troublesome organisms and philosophies for control of the microorganism growth.
Surface Materials and Properties Related to Seasonal Variations in Skid Resistance
Authors: Hill BJ , Henry JJ 
Published: March 2009

A three-year research program was initiated in 1978 at the Pennsylvania Transportation Institute by the U.S. Department of Transportation to investigate possible causes for seasonal and short-term skid resistance variations. The primary objective is to determine the parameters which can be used to predict the influence of seasonal and short-term effects. This paper is concerned with the material parameters influencing the long-term seasonal variations.
Data are analyzed from 21 test surfaces in State College, Pennsylvania and 10 test surfaces in Tennessee and North Carolina. The data include skid resistance measurements according to the ASTM Test for Skid Resistance of Paved Surfaces Using a Full-Scale Tire (E 274-79), British Pendulum Number measurements, calculated percent normalized skid number gradient, and average daily traffic volumes. An exponential curve is fitted to the skid number data for the asphalt pavements, while a linear relationship best fits the data for portland cement concrete surfaces. The coefficients of the resulting seasonal variation curves are regressed against pavement and traffic parameters to provide predictors for the long-term effects. Significant predictors are found to be British Pendulum Number and average daily traffic. Further predictors are suggested by the results of a pavement polishing experiment carried out on the 21 Pennsylvania test surfaces. Good agreement is observed between the two sets of test data.
Frictional Performance of Pavements and Estimates of Accident Probability
Authors: Burchett JL , Rizenbergs RL 
Published: March 2009

Objectives of this study were to evaluate standard and experimental surfaces throughout Kentucky in terms of skid resistance and effects of traffic, and to provide criteria for judging suitability of these surfaces to satisfy requirements for skid resistance and economics. The effects of traffic were quantified by regression analysis and scatter of data. Criteria included an estimate of accident risks, effects of speed on skid resistance, and seasonal variations in skid resistance.
Pavements on low volume roads (less than 1000 vehicles per day) maintained adequate skid resistances. Open-graded friction courses, with the possible exception of sections using phosphate slag aggregate, maintained adequate skid resistance to meet design requirements. The adequacy of other pavements may be judged from the criteria provided herein.
Estimates of accident reduction were made by combining the relationship between skid numbers and accidents with the distribution of skid numbers for each pavement type. Those reductions were used to calculate benefits that, along with costs of overlay, were used to determine benefit-cost ratios. Benefits exceeded costs for roads having annual average daily traffic (AADT) greater than 750, 2500, and 5000 and skid numbers (SN) less than 24, 30, and 35, respectively.
An Interactive Tire-Fluid Model for Dynamic Hydroplaning
Authors: Browne AL , Whicker D 
Published: March 2009

An interactive tire-fluid model has been developed to serve as an aid in understanding dynamic hydroplaning of pneumatic tires. Dynamic hydroplaning occurs when the amount of fluid encountered by the tire exceeds the drainage capacity of the footprint region. The tire is completely separated from the pavement by a fluid film.
Important advances in the present model are the automatic generation both of tire surface deformation in the contact region and of vertical axle displacement, both being due principally to fluid inertial forces. Present forms of the two major analysis modules comprising this model—tire deformation and fluid flow—are described in detail. Required experimental inputs including velocity, water film depth, and tire cross-sectional geometry are indicated. A description is then given of how these modules and the inputs they require are combined to form an interactive model. Examples are provided demonstrating the accuracy of the model's predictive capability. The effects of both speed and load on tire deformation in the footprint region and on axle height as predicted by the model are seen to be in agreement in trend with experimentally determined results.
Pavement Design and Controls for Minimizing Automotive Hydroplaning and Increasing Traction
Authors: Balmer GG , Gallaway BM 
Published: March 2009

The authors discuss test results and analyses of tire hydroplaning, skid resistance, and other tire-pavement interactions. They address roadway and vehicle operator controls for mitigating hydroplaning and improving highway safety.
The conclusions are based on analyses of simulation, laboratory, and full-scale tests. Pavement cross slope, texture, rut depth, pavement wear, surface drainage, drainage-path length, precipitation intensity and duration, tire inflation, tread-pattern depth, tire construction, and vehicle traveling speed influence hydroplaning tendencies and vehicle control.
Other factors considered are tire rolling resistance, vehicle fuel consumption, noise, splash and spray, and headlight glare.
These results are applicable to highway pavement design, construction, and rehabilitation; tire construction; and vehicle operation.
Comparison of the Friction Performance of a Passenger Car Tire and the ASTM Standard Test Tires
Authors: Henry JJ 
Published: March 2009

Tire-pavement friction data were obtained for three tires using a pavement friction tester conforming to ASTM Method E 274. The ribbed E 501 test tire, the blank E 524 test tire, and a commercial passenger car tire of similar size and construction were tested. When new and slightly worn, the passenger car tire produces higher friction under the E 274 test conditions than does the ribbed tire. For greater water film thicknesses it is shown that the slightly worn passenger car tires produce friction levels between those of the two standard test tires.
Braking distance tests were performed with the slightly worn passenger car tires on a diagonally braked vehicle in accordance with ASTM Method E 503. The results are compared with a prediction of braking distance calculated from longitudinal friction data obtained with a pavement friction tester operated over the same site under the same water film conditions. The calculations provide a conservative estimate of braking distance for use in estimating stopping sight distance.
Traction Modifications Resulting from Test-Induced Treadwear
Authors: Bernard JE , Ervin RD , Segel L 
Published: March 2009

Measurements have shown that the traction performance of pneumatic tires can be profoundly influenced by wear which accrues during the testing process. These findings indicate that changes can occur in the shear forces generated at both high and low slip angles as a consequence of testing at high angular slip. These performance changes are capable of significantly altering a vehicle's directional properties and thus suggest that data from tests involving high rates of test wear be interpreted with special caution.
The paper reviews and expands upon the basic findings through presentation of data taken on laboratory and mobile tire traction dynamometers and from vehicle tests for both passenger car tires and truck tires.
Characterization of Quick-Cure and Vacuum-Bag Cure Composites
Authors: Gleason DJ 
Published: March 2009

Current processing techniques for graphite/epoxy (Gr/Ep) composites require use of autoclaves. Because the autoclave is a major capital investment, materials that either eliminate the need for the autoclave or shorten autoclave cure times could reduce fabrication costs. The object of this study was to investigate composite materials that had short cure times and that were cured with vacuum-bag pressure only.
Two of the materials investigated were Hexcel HX565/T300 and Celanese diallyl phthalate (DAP)/C6000. Basic mechanical properties were determined initially for these systems. Because these initial results looked promising, the materials were further evaluated. These investigations included processing-time studies and fabrication and testing of a configured part. For the processing-time studies, viscosity profiles and interlaminar shear strengths were determined for several different cure cycles. The results did not indicate any advantage in altering the fast heat-up rate and short-cure-time cure cycle. The configured part evaluated was a hat-stiffened curved panel. Autoclave and vacuum-bag cured parts were tested in compression, in the post-buckling regime, and compared with a Gr/Ep system. The results from all tests indicate that the mechanical properties for these quick-cure and vacuum-bag cure systems are inferior to current Gr/Ep systems. However, the quick-cure and vacuum-bag cure materials might be cost effective in applications where minimum gage requirements make conventional Gr/Ep less efficient.
The Critical-State Pore Pressure Parameter from Consolidated-Undrained Shear Tests
Authors: Mayne PW , Swanson PG 
Published: March 2009

The results of isotropic and anisotropic consolidated-undrained shear tests (CIU, CK0, U) are used to determine the critical-state pore pressure parameter (Λo). The relative advantages of using the critical-state parameter (Λo) over Skempton's pore pressure parameter (A) and Henkel's parameter (a) are discussed. The effects of over-consolidation ratio (OCR) and initial stress state (K0) on both Henkel's and Skempton's pore pressure parameters can significantly alter effective stress predictions of undrained strength. The critical-state parameter is independent of OCR, K0, and level of shear to failure, thus requiring only two basic soil constants in order to predict undrained strength: (1) the effective stress friction angle (φ'), and (2) the critical-state pore pressure parameter (Λo).
An “extended” critical-state model is developed using the equivalent pressure concept for overconsolidated states. The method then provides a simple analytical representation of undrained stress-strain behavior and pore pressure response for clays with different values of OCR. One additional soil constant (Cc: the virgin compression index) is required in order to model stress-strain behavior.
The validity of the critical-state theory is substantiated by data from over ninety different clay and silt soils reported in the geotechnical literature. Furthermore, the critical-state concepts are shown to encompass both total stress and effective stress methods under one unified theory.
A Simple Crack Closure Model for Prediction of Fatigue Crack Growth Rates Under Variable-Amplitude Loading
Authors: de Koning AU 
Published: March 2009

A model for the prediction of growth rates of fatigue cracks in aluminium alloys is presented. The model is based on an approximate description of the crack closure behavior and can be used to predict effects of crack growth acceleration and retardation observed experimentally under variable-amplitude loading.
A computer program was developed for analysis of fatigue crack growth. It was used to analyze the effect of certain parameter variations in a flight simulation load spectrum on the crack growth rate. For 7075-T6 thin sheet material the results are compared with experimental data.
Effect of Cyclic Frequency on the Corrosion-Fatigue Crack-Initiation Behavior of ASTM A517 Grade F Steel
Authors: Taylor ME , Barsom JM 
Published: March 2009

This study was conducted to investigate the effect of cyclic frequency on the corrosion-fatigue crack-initiation behavior in regions of stress concentration in ASTM A517 Grade F steel. The tests were conducted on notched compact tension specimens at a stress ratio of 0.1 in a room-temperature 3.5 percent solution of sodium chloride. The test results showed that the corrosion-fatigue crack-initiation life under full immersion conditions was significantly less than the fatigue-crack-initiation life in air. Moreover, the test results showed no effect of cyclic frequency in the range of 12 to 300 cpm on the corrosion-fatigue life. The data indicate the possible existence of a corrosion-fatigue crack-initiation limit, below which cracks did not initiate, at a ΔK/√ρ of about 172 MPa (25 ksi). This value of ΔK/√ρ corresponds to a maximum stress range, Δσmax, of about 207 MPa (30 ksi) and is one-fourth the value for the fatigue-crack-initiation limit in air.Fatigue-crack-initiation tests results on precorroded notched specimens showed a 25 percent reduction in the fatigue-crack-initiation limit. This decrease was attributed to an increase in the stress concentration caused by corrosion pits on the surface of the notch radius.Metallographic investigations showed that corrosion-fatigue cracks initiate at corrosion pits on the surface of the notch tip. These cracks initiate as microcracks that form by a sharpening of the corrosion-pit tip under the combined influence of the environment and cyclic loads. No relationship was found between microstructure and corrosion-pit sites.
Evaluation of Fly Ash Leachability Using Batch Leaching Procedures
Authors: Sack WA , Boomer BA , Tarantino JT , Keefer GB , Seals RK , Miller M 
Published: March 2009

The leachability of two fly ashes was evaluated using two different proposed procedures environmental Protection Agency-Extraction Procedure (EPA-EP) and American Society for Testing and Materials method (ASTM). The EP test was also run to study the influence of contact time and the presence of dissolved oxygen. Finally, a modified EP was carried out with repeated extraction of the same ash with fresh leachate and repeated contact of the same leachate with fresh ash. Both acid and deionized water extractions were used.
The EP test was found to extract more material than the ASTM procedure on a milligrams per kilogram of ash basis, although the ASTM test gave higher concentrations. For the contact times studies (2 to 48 h), no one elution time could be chosen which would allow equilibrium for all parameters. Although certain elements evidenced sensitivity to the presence or absence of oxygen, no general pattern was found. Release during repeated extraction of the same ash with fresh leachate was found to be highly pH dependent. Most of the mobilization tended to occur in the first two extractions for the acid test, while release occurred more gradually for 5 to 7 elutions using deionized water.
Comparison of Three Solid Waste Batch Leach Testing Methods and a Column Leach Test Method
Authors: Jackson K , Benedik J , Jackson L 
Published: March 2009

As a participant in the American Society for Testing and Materials (ASTM) program evaluating U.S. Environmental Protection Agency (EPA) and ASTM solid waste extraction procedures, the Laramie Energy Technology Center of the U.S. Department of Energy has been conducting a study comparing various aspects of batch versus column extraction techniques. This study evaluates three batch extraction methods and compares these results with results obtained from column leach tests.
A standard fly ash material was leached using three types of mixers, five liquid-to-solid ratios, and leach times ranging from 1 h to 96 h. The leachates were analyzed using an atomic absorption spectrophotometer equipped with a graphite furnace for the following metals: selenium, chromium, arsenic, lead, and cadmium. The pH was also determined on all the leachate samples.
The data show that the batch test can be improved by increasing the liquid-to-solid ratio. The data also indicate that the leaching time can be decreased. Comparison of the data from the batch and column leach tests indicates that a correlation may exist.
Comparison of Inductively Coupled Plasma and Atomic Absorption Spectroscopies for Determination of Twenty-five Elements in Fly Ash Leachate Solution
Authors: Drenski TL , Paxton CA , Varnes AW 
Published: March 2009

Atomic absorption (AA) spectroscopy is the approved method for determining metallic and semimetallic elements in aqueous specimens. When many elements are required on a specimen, however, it is a tedious technique, because only one or two elements can be determined at a time. Inductively coupled plasma (ICP) emission speetroscopy, however, is capable of determining up to 50 elements in a single determination, printing out results in less than 2 min.
Data obtained in this study show that for compliance purposes, acceptable agreement is obtained between AA and ICP for 25 elements in fly ash leachate, a fairly complex matrix. Procedures are described for overcoming interference effects encountered in AA. An automated system for ICP is described briefly. Where significant differences were found between the techniques, possible causes and solutions are proposed.
Evaluation of Methodology for the Survey Analysis of Solid Wastes
Authors: Miller HC , James RH , Dickson WR , Neptune MD , Carter MH 
Published: March 2009

This paper presents the results of an experimental program of evaluation of analytical methods for “total content” (survey analysis) of residual wastes. Candidate methods were first studied and modified, and then evaluated with the analysis of a variety of residual waste specimens and determination of a broad range of organic compounds and metals. The methods depend on extraction, gel permeation chromatography (GPC) cleanup, preconcentration, and gas chromatography/mass spectrometry (GC/MS) analysis for identification and quantitation of semivolatile organics; purge-and-trap and GC/MS for purgeable organics; and acid digestion combined with atomic absorption spectroscopy (AAS) or inductively coupled plasma emission spectroscopy (ICP) determinations for metals.
The results of the study are presented in terms of observed accuracy and precision and are based on statistical analysis of over 10 000 data points.
Testing of Materials for Use in the Lining of Waste Disposal Facilities
Authors: Haxo HE 
Published: March 2009

The lining of waste disposal facilities with materials of low permeability is a feasible means of preventing potentially polluting constituents in wastes impounded on the land from seeping out of the impoundment and entering the groundwater. A great array of materials, including fine-grain soils and clays, asphaltic compositions, concretes, and polymeric membranes, are potential candidates for use as liners.
The use of materials for lining waste impoundments and disposal facilities is comparatively new, and experience in their field performance is limited. Considering the variety of lining materials that are available and the vast number of compositions of the waste streams that must be impounded, a body of test methods is needed to: (1) guide the selection of liners for specific applications, (2) assure that the quality of the liner that has been selected is placed on the site, and (3) monitor the condition of the liner during service.
This paper discusses the test methods that are currently available for use in liner technology, and describes an overall approach to the testing of liners, principally membrane liners. Emphasis is placed on tests needed for liner selection and impoundment design. Of particular interest are the descriptions of several tests designed to simulate the conditions of service of liners in actual waste impoundments. Data from two ongoing Environmental Protection Agency (EPA) liner research projects are presented to illustrate the tests that are described.
Porous Titanium Alloy for Prosthesis Attachment
Authors: Wheeler KR , Karagianes MT , Sump KR 
Published: March 2009

Void metal composite (VMC) is a porous metal developed to fix a prosthesis to bone by tissue ingrowth. The material is made by techniques which produce structures with controlled porosity, density, and physical properties. The ability to produce a range of structures creates opportunities to study the effects of pore size, shape, and density on bone-metal interface strength.
Ti-6Al-4V is the metal of choice for VMC. This titanium alloy was selected for its corrosion resistance, good mechanical properties, low density, and good tolerance by body tissue. Structures with spherical pore sizes ranging from 275 to 650 μm have been fabricated, with up to 80 percent theoretical densities. Cylindrical pores with controlled direction and arrangement were also produced. The optimum structure for attachment strength seems to be a pore size of 450 μm and 50 percent theoretical density.
Titanium alloy porous implants are well tolerated by body tissue. Intramedullary pins having up to 18 months' implant time and dental implants having 4 years' implant time show development of strong bonds to bone with no adverse tissue reaction.
Statistical Design and Analysis of an Interlaboratory Program on the Fatigue Properties of Welded Joints in Structural Steels
Authors: Haibach E , Olivier R , Rinaldi F 
Published: March 2009

The constant-amplitude fatigue behavior of welded joints in two types of normalized structural high-strength steel has been studied in an interlaboratory program within the European community. The statistical design and analysis of a part of that program is described. This part was aimed at establishing complete S-N curves for three types of fillet welded joints with reference to a comprehensive statistical test plan. The test plan closely linked the activities of six laboratories involved in testing and three welding institutes fabricating the specimens under specified conditions, and it organized the repartition of the specimens to the stress levels to be applied and to the laboratories. Some restrictions, however, were imposed on the test plan due to limitations in test load capacity in some of the laboratories and to limitations in time and costs.
The results were evaluated according to the concept followed in planning, using various methods of analysis that were outlined and compared in treating the 753 test results available and in deducing characteristic figures of the fatigue strength at 2·106 cycles. The assumption of a “uniform” slope of S-N curves for welded joints in structural steel proved to be reasonable. Moreover, it was possible to analyze the additional variability of the results caused by sharing the tests at each stress level among several laboratories or caused by fabricating equal portions of the specimens in three welding institutes.
Measurement Techniques for Fuel Stability Characterization
Authors: Cummings AL , Pei P , Hsu SM 
Published: March 2009

A measurement technique has been developed to characterize the oxidation stability of liquid fuels under various conditions. The technique is based on high-pressure differential scanning calorimetry (DSC). It is shown to be sensitive to the chemical compositions of some fuels, including shale-derived jet fuel and a marine diesel fuel. These fuels were subsequently fractionated according to molecular type using liquid chromatography. Using the procedure developed, the oxidation characteristics of the fuel fractions were examined. The results suggest that the different amounts of the various molecular types present in different fuels may affect the overall stability of the fuels.
The DSC technique offers many advantages in terms of precision and sample size requirement, as well as in the number of parameters measured.