bluuebunny/crossref_metadata_2025 huggingface dataset:
Hazards of Toxicity Information
Authors: Wiseman LM
Published: December 2008

The Occupational Safety and Health Administration's (OSHA) Hazard Communication standard, state and local right-to-know laws, and a heightened public awareness of environmental issues have created new demands for information on the toxicological properties of chemicals and products. Several computer-searchable database producers have attempted to respond to these new demands by collecting and managing the growing amount of data and generally making it more easily and widely available.

Transforming this data into usable information presents some problems, especially since some of it may be of questionable quality or value. How do we increase our management's, our employees', and our customers' understanding of the true hazards associated with chemicals and products? What and how do we communicate to our various audiences—plant workers, health and safety professionals, management, marketing personnel, customers, and legislators? How do we ensure that we are providing information that is not only accurate and complete, but also usable and understandable? This paper presents one industrial organization's approach to the problems of handling toxicity information.

Celanese Corp. believes that information of the toxic properties of any chemical used in the company's processes or the toxicity of the company's final products is a basic component in the chemical's risk assessment. A Material Safety Data Sheet (MSDS) will effectively communicate accurate environmental, health, and safety information. Significant toxicological data will be communicated to employees, affected customers, regulatory authorities, and the public. The Toxicology Department has developed two documents, a Toxicity Summary and a Toxicity Evaluation, that can be used at the beginning of the communication process.

All those at Celanese involved in hazards communication share two ongoing responsibilities. One is for continuous analysis and verification of data on the toxic effects of chemicals. The second is to impart quality information to others—be it as an MSDS, a “Dear Customer” letter, or a briefing to employees—that will heighten their awareness and increase their understanding. It has been and will continue to be a learning process.
Using the Micro-CSIN Workstation to Provide Chemical Hazard Information
Authors: Hushon JM , Conry TJ
Published: December 2008

Chemical hazards are of two basic types: emergency situations presenting imminent danger to humans or the environment and existing hazards such as dump sites or chemical storage areas. The information requirements and tools available for responding to these two types of hazards are different, and the Micro-CSIN Workstation developed by Bolt Beranek and Newman (BBN) under the sponsorship of the Council on Environmental Quality (CEQ), the Environmental Protection Agency (EPA), the National Library of Medicine (NLM), and the Centers for Disease Control (CDC), can respond to both.

Emergencies require rapid access to factual data. The Micro-CSIN Workstation permits rapid retrieval of factual data stored in three databases: Hazardous Substances Data Bank (NLM/TOXNET), Hazardline (OHS), and Ohmtads (CIS) according to a prestored, userspecified, retrieval profile. The data are then organized by subject area into a report. The Workstation also has the ability to rapidly retrieve chemical identification information.

In a nonemergency situation, it is possible to carry out a more thorough search of the literature. The Micro-CSIN Workstation makes use of a general bibliographic script to access and retrieve any of several hundred bibliographic databases available through Bibliographic Retrieval Systems (BRS), Chemical Abstracts Service (CAS), Dialog, NLM, and Systems Development Corp. (SDC). These more current and in-depth data can be used to supplement the chemical summary information.

For a company responding to the right-to-know laws, the chemical summaries are ideal, especially if supplemented by additional, more recently published results. One way of organizing right-to-know information is to organize all data into two computerized files using a database management software package. BBN uses RS/1, one of its software products. The two files cover (1) product-related information and (2) chemical-related information, and the files are cross-indexed. The structures of these files are presented along with a possible data management scheme for storing and manipulating local site data, material safety data sheets (MSDSs), chemical content information, and chemical-specific data needed to respond to the laws. It is in identifying and retrieving chemical-specific data that the Micro-CSIN Workstation technology is particularly valuable.
Hazard Communication Information: A History and Commentary on the MSDS Problems
Authors: Bransford JS
Published: December 2008

The history of “Need to Know,” which became “right to know,” began at the Occupational Safety and Health Administration (OSHA) in 1973. The immensity of the task of maintaining and tracking the constantly changing health effects and toxicity data required for material safety data sheets (MSDS) and labels changed the regulators' planned methodology. The emergence in recent years of the courtroom principle of strict liability changed the views of the large chemical manufacturers. The right-to-know standard became a vehicle to downshift some liability away from the suppliers to the supplied parties. The courts took a contentious stand against the restrictive policy of OSHA, which covers only those workers in manufacturing, and ordered a widening to cover all workers falling under federal authority. The courts have been breaking down the ability of a manufacturer or formulator to withhold trade secrets from the MSDS data, and in Nov. 1985 OSHA published a new revised policy.

The communities, which include police, firemen, and in some states the public at large, are claiming rights to the information. Some 35 states have already passed right-to-know legislation in one form or another with a high probability that other states will follow suit.

The technical staff requirements for in-house maintenance and the creation of MSDS information is beyond the reach of many chemical manufacturers and formulators in terms of personnel requirements and the need for an extensive chemical, biological library. Many corporate users have not digested the import of multiple suppliers with drastically different MSDSs on commodity chemicals which they purchase from many manufacturers. The liability will be assessed by the courts in terms of the weakest MSDS whether such MSDS was provided to the worker or not. Such weak MSDSs will be obtained for possible entry as evidence through the discovery process.
Evaluation of a Variable-Speed Impact Tester for Analysis of Impact Behavior of Plastics and Composites
Authors: Kamal MR , Samak Q , Provan J , Ahmad V
Published: December 2008

The Rheometrics variable-speed impact tester (RVSIT) was evaluated with regard to the stability and reproducibility of the velocity and load signals. A drop in the speed of the probe was observed upon impact. The extent of the drop depends on the impact speed and the material tested. Mounting the load cell ahead of the impact rod was found to improve the reproducibility of load-deflection signals and to alleviate spurious postpuncture noise. A new rod was designed to apply circumferential loads on notched specimens. Load-deflection data obtained with this type of loading were used to calculate the dynamic critical stress intensity factors (SIF) for sheet molding compound (SMC) and reinforced reaction injection-molded (RRIM) polyurethane panels in the opening and the sliding modes.
Impact Measurements of Low-Pressure Thermoplastic Structural Foam
Authors: Progelhof RC
Published: December 2008

The most common technique used to report the impact characteristics of a plastic member found in the literature today is the drop-weight-to-fracture test, the ASTM Test for Impact Resistance of Rigid Plastic Sheeting or Parts by Means of a Tup (Falling Weight) (D 3029-82). An impactor or tup of specified mass is dropped from a known height. Through the use of a staircase testing procedure, the probable energy required to crack 50% of the specimens, F50, is obtained. The use of this experimental technique for thermoplastic structural foam members can result in misleading data.

A series of constant velocity instrumented impact tests were conducted on several sets of test plaques. The impact energy correlated with the local density of the member, but relatively large variations did occur between identical positions on “identical” plaques. The experiments clearly indicate that the basic premise that the drop-weight-to-fracture test must be conducted on “identical” sets of specimens from a single population is not valid for thermoplastic structural foam specimens.
Instrumented Impact Testing of Aramid-Reinforced Composite Materials
Authors: Wardle MW , Zahr GE
Published: December 2008

Instrumented impact testing has been applied to study the effect of fiber properties on the impact damage tolerance of fiber-reinforced composites containing aramid, carbon, and glass fibers. The energy-absorbing capability of fibrous composites in impact is dependent on the tensile strain capacity (toughness) of the fibers, as well as on properties of the resin and interface. The aramid fibers are particularly efficient in energy absorption and in retention of properties after impact.
Effects of Test Rate and Temperature on Fracture Behavior of Some Rubber-Modified Polymers
Authors: Gaggar SK
Published: December 2008

The fracture behavior of acrylonitrile-butadiene-styrene (ABS) and rubber-modified polyvinyl chloride (PVC) at various test temperatures and test rates was studied. The ductile-brittle transitions, in terms of test rate and test temperature, were established in each case, and the effects of material structural parameters on such transitions were studied. In modified PVC it is shown that the presence of the rubber modifier causes a shift of the ductile-brittle transition of unmodified PVC to a higher test rate at a given test temperature. The presence of an elastomeric phase in ABS induces a ductile failure mode in an otherwise brittle matrix over a broad range of test rates and temperatures. The ductile-brittle transition in ABS shifts to lower test temperatures as the rubber level is increased.
Effect of Loading Rate on the Impact Fracture Toughness of Acetal and Polymethyl Methacrylate
Authors: Goolsby RD , Lin C
Published: December 2008

This investigation is concerned with evaluating the suitability of fracture mechanics testing and analysis methods for characterizing the impact fracture resistance of polymers. The polymers characterized in this study were acetal and polymethyl methacrylate. A precracked three-point bend specimen configuration was selected for fracture characterizations, with tests being conducted at rates from 2.12 × 10−5 to 1.06 m/s. Tests at each loading rate were conducted with specimens having three different crack-length-to-specimen-width ratios, a/W. Specimens were instrumented with a clip gage at the notch opening, and a potential drop technique was also employed during testing to delineate critical crack instability. All the tests were performed on an Instron servohydraulic instrumented impact test system specifically designed and instrumented for impact testing of polymers. Plane-strain fractures were observed for all the specimens tested, and linear elastic fracture mechanics methods were employed for data analyses. Plane-strain fracture toughness was observed to be relatively constant with increasing a/W ratio for both polymers, except for those specimens tested at the highest loading rate. It was also found that fracture toughness was significantly influenced by loading rate, with transitions in toughness occurring for both polymers at particular rates of loading. The authors postulate that these transitions are associated with molecular relaxation mechanisms and a change of thermal state at the crack tip.
Seasonal Variation in Airtightness of Two Detached Houses
Authors: Kim AK , Shaw CY
Published: December 2008

Fan pressurization tests on two unoccupied houses were conducted once every two weeks for a period of a year (May 1982 to July 1983) to determine the seasonal variation in airtightness. Both houses are of insulated wood frame construction. House No. 1 was built with more insulation than is required by the local building code, and a polyethylene vapor barrier was applied with special care to improve its airtightness. House No. 2, a less airtight house, was built with various wall construction features and a polyethylene vapor barrier in only two walls.

Indoor relative humidity, indoor and outdoor air temperatures, and moisture content of the stud and top plates of the wood framing were measured at the time of airtightness testing to determine whether a correlation exists between these factors and house airtightness. The results indicate that air leakage varies throughout the year, with the minimum value in late summer and fall and the maximum value in winter and early spring. The difference is more pronounced in the leakier house. There is also indication of a rough correlation between envelope airtightness and indoor humidity ratio.
Air Leakage in Industrial Buildings—Description of Equipment
Authors: Lundin LI
Published: December 2008

Air leakage in industrial buildings—preliminary results: The National Testing Institute is currently investigating air leakage in industrial buildings. In 1980 the Institute was asked to carry out a number of pressurization/depressurization tests in industrial buildings. The buildings that were tested were constructed according to two different principles: light-concrete elements attached to a prefabricated concrete frame and sheet metal attached to a steel frame insulated with mineral wool. The measurements were asked for by a manufacturer of building materials. The results indicate that some industrial buildings are very leaky and some are very airtight. Therefore Nordtest has asked us to develop a method for pressurization tests of large buildings and for equipment to carry out those tests. The paper will describe the equipment and present preliminary results.
The Measurement of Air Infiltration in Large Single-Cell Industrial Buildings
Authors: Waters JR , Simons MW
Published: December 2008

Measurements of the air infiltration rate of three large single-cell buildings have been carried out using the tracer dilution method. The purpose of the measurements was to determine whether or not there are any special difficulties in using the tracer dilution method in this type of building prior to embarking on a more substantial measurement program. The tracers used were nitrous oxide and sulfur hexafluoride. Both were found to be satisfactory, but it was concluded that sulfur hexafluoride, in conjunction with a portable gas chromatograph, performed more reliably when used for on-site measurements and therefore was to be preferred.
Some Induced-Pressure Measurements in a High-Rise Office Building
Authors: Hunt CM
Published: December 2008

Induced-pressure measurements were made in the tower of an eleven-story office building using a fan of 7.55-m3/s capacity. The fan was used to depressurize the entire tower as well as a single floor. Sulfur hexafluoride (SF6) tracer gas was used to trace air movements from floor to floor during single-floor depressurization.

Average flow coefficients of approximately 5 × 10−4 m3/m2 · s · Pa0.65 for the tower and 7 × 10−4 m3/m2 · s · Pa0.65 for the single floor were estimated from single point measurements. The effect of opening and closing office doors also was determined.

By simultaneous solution of flow equations for the whole tower and a single floor, it was estimated that about 80 to 90% of the airflow during depressurization of a single floor came from floors above and below. From SF6 tracer gas measurements, it was estimated that about 50% of the flow could be traced to the floor below.

The pressure difference measurements upon which the previous estimates are based were in the 3- to 10-Pa range. Uncertainties in the estimates of flow coefficients and air-flow from above and below are discussed in the text. The results essentially are descriptive, but they suggest an experimental approach to the determination of flow coefficients for modeling through the wall and for floor-to-floor components of airflow in building ventilation.
Measured Air Infiltration and Ventilation Rates in Eight Large Office Buildings
Authors: Grot RA , Persily AK
Published: December 2008

Air infiltration and ventilation rate measurements were made during all seasons of the year in eight federal office buildings using an automatic air infiltration system designed at the National Bureau of Standards. The eight federal office buildings were located in Anchorage, Alaska; Ann Arbor, Michigan; Columbia, South Carolina; Fayetteville, Arkansas; Huron, South Dakota; Norfolk, Virginia; Pittsfield, Massachusetts; and Springfield, Massachusetts. These buildings ranged in size from 1730 m2 (18 600 ft2) for the building in Pittsfield to 45 500 m2 (490 000 ft2) for the Anchorage federal building. All were constructed within the last 10 years. Air infiltration rates were found to vary from 0.2 to 0.7 air changes per hour and constituted from 23% to 61% of the building design load. Minimum ventilation rates in the tighter buildings were found to be less than what would be recommended for occupied offices.
Pressurization Testing of Federal Buildings
Authors: Persily AK , Grot RA
Published: December 2008

Seven federal buildings ranging in size from 1900 to 48 000 m2 of floor area were pressure tested to determine the airtightness of the building envelopes. These tests are part of a larger project to evaluate the thermal integrity of the envelopes of federal buildings. The buildings were pressurized using the air-handling equipment in the buildings and a constant-injection, tracer gas technique to measure the airflow through the fans. In addition, selected windows in some of these buildings were pressure tested separately to determine the airtightness of individual components.

The results of the whole building and component pressurization tests are presented and discussed. In addition, the component pressurization test results are used to estimate the contribution of the windows to the total building air leakage. The results of the building pressurization tests are compared empirically to measured infiltration rates on the same buildings. The large building infiltration model developed by Shaw and Tamura of the National Research Council of Canada is applied to the buildings to predict air infiltration rates induced by weather.
Detailed Description and Performance of a Passive Perfluorocarbon Tracer System for Building Ventilation and Air Exchange Measurements
Authors: Dietz RN , Goodrich RW , Cote EA , Wieser RF
Published: December 2008

The manufacturing procedures for and the performance of a building air infiltration kit consisting of miniature passive perfluorocarbon tracer (PFT) permeation sources and passive adsorption tube samplers are described. With four PFT types available, homes and buildings with up to four separate zones can be evaluated fully under steady state conditions for the air infiltration and exfiltration rates from each zone as well as for the air exchange rates between zones using this inexpensive and nonobtrusive field kit. Complete details on deployment in homes and on gas chromatographic analysis of the passive samplers are presented. Examples of total air changes per hour (ACH) results in several studies showed average values between 0.25 to 0.64 h−1. A generalized correlation was used to characterize the leakiness of eleven homes in the United States and Canada, showing ACH dependency only on inside-outside temperature difference, on wind speed to the 1.5 power, and on a subjective terrain factor; the approach has application in evaluating weatherization performance. Details of multizone measurements in four homes provided insight into the role of attics, crawl spaces, and basements on the indoor air quality and weatherization needs for the living zone.
Comparison of Measured and Predicted Infiltration Using the LBL Infiltration Model
Authors: Sherman MH , Modera MP
Published: December 2008

The Lawrence Berkeley Laboratory (LBL) infiltration model was developed in 1980; since that time many simultaneous measurements of infiltration and weather have been made, allowing comparison of predictions with measured infiltration. This report presents the LBL model as it currently exists and summarizes infiltration measurements and corresponding predictions. These measurements include both long-term and short-term data taken in houses with climates ranging from the mild San Francisco Bay area to the more extreme Midwest. These data also provide a data base for comparison with other infiltration models and provide a starting point for the determination of the accuracy and precision of air infiltration models.
Constrained 90-Deg Ply Cracking in 0/90/0 and ±45/90/∓45 CFRP Laminates
Authors: Peters PWM
Published: December 2008

The strength distribution of 90-deg plies in the laminates (±θ/90n)s with θ = 0 deg and 45 deg and n = 2, 3, and 6 is described in the form of a two-parameter Weibull distribution. A common feature for both orientations of surface layers is that at decreasing 90-deg ply thickness the characteristic strength and shape parameter increase. The reason is that the surface layers suppress a growth of the defects in the 90-deg ply which are lying close to the interface with the surface layers. This causes the apparent shape parameter to increase from a value a = 6.4 for a thick 90-deg ply (which is comparable to the shape parameter determined on a unidirectional laminate) to a shape parameter of a = 10.47 for a thin 90-deg ply (n = 2) in case of the (02/90n)s laminate. Further, it is shown that crack formation in the 90-deg plies of the (±45/90n)s laminates is strongly influenced by the severe edge stresses. This causes the applied one-dimensional fracture strain criterion to be inaccurate for the (±45/90n)s laminates.
Failure Analysis of a Graphite/Epoxy Laminate Subjected to Bolt-Bearing Loads
Authors: Crews JH , Naik RVA
Published: December 2008

Quasi-isotropic graphite/epoxy laminates (T300/5208) were tested under bolt-bearing loads to study failure modes, strengths, and failure energy. Specimens had a range of configurations to produce failures by the three nominal failure modes: tension, shearout, and bearing. Radiographs were made after damage onset and after ultimate load to examine the failure modes. Also, the laminate stresses near the bolt hole were calculated for each test specimen configuration, and then used with a failure criterion to analyze the test data.

Failures involving extensive bearing damage were found to dissipate significantly more energy than tension-dominated failures. The specimen configuration influenced the failure modes and therefore also influenced the failure energy. In the width-to-diameter ratio range of 4 to 6, which is typical of structural joints, a transition from the tension mode to the bearing mode was shown to cause a large increase in failure energy.

The failure modes associated with ultimate strength were usually different from those associated with the damage onset. Typical damage sequences involved bearing damage onset at the hole boundary followed by tension damage progressing from the hole boundary. Ultimate failures involved shearout beyond the clampup washer for specimens with small edge distances and involved bearing damage beyond the washer for larger specimens. Strength predictions indicated that the damage corresponding to ultimate strength was governed by the maximum stress near the hole.
Delamination Arrester—An Adhesive Inner Layer in Laminated Composites
Authors: Chan WS
Published: December 2008

Delamination arrestment in laminated composites has been achieved by using tough adhesive strips embedded in the interior of the laminate. For (± 302/903/∓302)T and (±35/0/90)s laminates, edge delamination was arrested under both static and fatigue tension loadings. For the (±302/903/∓302)T laminates, delamination was delayed and fatigue life was significantly increased. These results are attributed to the G1 component of the total strain-energy release rate decreasing as delamination approaches the adhesive strip region. It is suggested that the initiation of delamination for both static and fatigue loadings is mainly due to the highest G1 component in the laminate, not the total G. A characterization of fatigue behavior is discussed. It was found that delamination growth rate decreases as the number of fatigue cycles increases.
Fatigue Failure Mechanisms in Unidirectional Composites
Authors: Lorenzo L , Hahn HT
Published: December 2008

The tension fatigue behavior of unidirectional composites has been studied using model composites where bundles of E-glass and T300 graphite fibers were combined with ductile and brittle epoxies. Model specimens allowed one to monitor and identify the basic failure mechanisms which are difficult to detect in real composite coupons. Fatigue failure modes and the sequence of damage accumulation depended on the stress level. Matrix microcracks between fibers normal to the applied load were subcritical failure mechanisms which occurred early during fatigue in both glass and graphite bundles. In graphite fiber bundle, they were initiated at the interface along the fibers and were rather isolated. These microcracks were not deleterious in that they neither triggered fiber failures nor grew bridging the fibers. At medium and high cyclic stresses, degradation of the glass as well as the graphite bundle in the form of fiber failures was observed. In glass specimens, extensive interfacial failure and matrix cracking followed while in graphite bundles matrix cracking occurred close to the zones of accumulation of fiber breaks. At low stress levels, only matrix microcracking and few scattered fiber failures were seen.
Internal Load Distribution Effects During Fatigue Loading of Composite Laminates
Authors: Highsmith AL , Reifsnider KL
Published: December 2008

Two fundamental processes govern the reduction of strength and stiffness of composite laminates caused by cyclic loading, commonly called the “fatigue effect.” One process is the reduction of the strength and stiffness of the individual constituent materials in the composite, caused by events such as localized nonconservative deformation, microcrack formation, and substructure variations. This process is essentially the source of the “fatigue effect” homogeneous materials, except that macrocrack formation and fracture dominated by a single crack generally does not occur as a consequence of this process in composite materials. In laminated composites there is another fundamental process which plays a major role in determining residual properties. That process is the damage-dependent redistribution of load sharing among the plies of the laminate caused by the continuous variation of the elastic stiffness properties of each ply induced by microdamage development in those plies. Experience suggests that this process is critical and, in some cases, dominant in the determination of the residual strength and life of a laminate under cyclic loading. This paper addresses the experimental and analytical aspects of this fundamental process. The results of the present work indicate that strain (and stress) redistributions in regions of highly localized damage are large and significant. The general nature of these redistributions has been established, which provides the first firm foundation for the formulation of the philosophy needed to interpret these physical damage states in terms of residual strength and life.
On the Interrelationship Between Fiber Fracture and Ply Cracking in Graphite/Epoxy Laminates
Authors: Jamison RD
Published: December 2008

The present work examines in a systematic way the development of microdamage in several laminates of graphite/epoxy material subjected to both quasi-static tensile loading and tension-tension fatigue. Emphasis is placed upon discriminating and quantifying matrix and fiber microdamage. Penetrant-enhanced standard- and stereo X-ray radiography were used along with edge replication to follow the progression of matrix damage. The recently developed technique of laminate deply was used to map the development of fiber fracture.

The most significant result, confirmed in both the quasi-static and fatigue tests, was the dominant role played by off-axis ply cracks in the fracture of fibers in adjacent load-bearing plies. By direct observation of fiber fractures in situ, it was established in both cases that fiber fractures do not occur in a random pattern at elevated loads/cycles, but instead occur in narrow bands adjacent to off-axis ply cracks. It is the action of these crack tips upon adjacent fibers which may govern the wearout or overload of laminates under these conditions.

By direct accounting of fiber fractures in deplied laminae taken from damaged but unfailed laminates, the relationship between the density of fiber fractures and the number of cycles at one cyclic stress level is reported. The relationship between fiber fracture density and quasi-static stress level is reported as well.

For the quasi-statically loaded specimens, efforts to characterize and discriminate between fiber fracture and transverse ply cracking on the basis of acoustic emission (AE) amplitude distribution are described. Correlations between attributes of the AE amplitude distribution and the established damage extent and chronology are reported. Common assumptions regarding the contributions of these distinct damage modes to acoustic emission from laminates under tensile loading are discussed in terms of the present evidence.

Finally, in comparing damage resulting from quasi-static tension loading of cross-ply laminates with that observed in tension-tension cyclic loading of laminates of similar graphite/epoxy material, microdamage modes unique to fatigue are identified and discussed.
A Critical-Element Model of the Residual Strength and Life of Fatigue-Loaded Composite Coupons
Authors: Reifsnider KL , Stinchcomb WW
Published: December 2008

This paper addresses the basic question of how to develop a mechanistic cumulative damage model that has the capability of describing and predicting the strength and life of high-modulus continuous-fiber composite laminates subjected to general cyclic loading. The paper is a first step in philosophy from phenomenological descriptions of composite laminate fatigue behavior to mechanistic modeling based on the physics and mechanics of the details of the laminate response during cyclic loading. The major point of departure of the present effort from prior modeling activities is the mechanistic approach.
Response of Thick, Notched Laminates Subjected to Tension-Compression Cyclic Loads
Authors: Bakis CE , Stinchcomb WW
Published: December 2008

The fatigue response of a [(0/45/90/ −45)s]4 T300-5208 graphite/epoxy laminate with a drilled center hole subjected to constant-amplitude, fully reversed tension-compression loading was investigated. Damage evaluation techniques such as stiffness monitoring, penetrant-enhanced X-ray radiography, C-scan, laminate deply, and residual strength were used to establish the mechanisms of damage development as well as the relations between this damage and the stiffness, strength, and life of the laminate. Two load levels provided for fatigue lives of 105 to 106 cycles and significant stiffness reductions. Damage initiated at the hole as matrix cracking parallel to the fibers in all plies. Matrix cracks had a significant effect on delamination initiation and growth. Delaminations initiated near the surface in the densely cracked region at the hole and grew along major matrix cracks. Delaminations of smaller extent developed later throughout the interior of the laminate and followed similar growth patterns as those closer to the surface. Compressive properties degraded more rapidly than tensile properties. At the stress levels used in this investigation, residual tensile strength increased early in the fatigue life and remained approximately constant to near the end of life, when failure was precipitated by excessive laminate instability during the compressive portion of the loading.
Recent Studies to Investigate Effects of Tire Footprint Aspect Ratio on Dynamic Hydroplaning Speed
Authors: Horne WB , Yager TJ , Ivey DL
Published: December 2008

Previous National Aeronautics and Space Administration (NASA) Langley aircraft tire friction performance investigations indicated the primary parameter influencing dynamic tire hydroplaning was inflation pressure. The empirical equations derived from aircraft tire test data to estimate tire hydroplaning speed were considered applicable to all pneumatic tires. Some recent studies of several tractor-trailer accidents on flooded highway surfaces, however, suggest that in addition to inflation pressure, truck tire footprint aspect ratio (tread contact area width to length) may significantly effect dynamic hydroplaning speed. Although the truck accident data indicated a new equation to predict highway vehicle dynamic tire hydroplaning speed, collection of additional test data was considered necessary. Tests aimed at obtaining this needed data were initiated by researchers at Texas Transportation Institute (TTI) and NASA Langley. Results from these initial tests using a worn truck tire, an ASTM Specification Standard Tire for Pavement Skid Resistance Tests (E 501) and Specification for Smooth Tread Standard Tire for Special-Purpose Pavement Skid Resistance Tests (E 524) tires are discussed in this paper. The status of the work directed towards developing a new dynamic tire hydroplaning speed equation(s) is reviewed. During wet weather, highway vehicle operators are cautioned to be alert to the possibly lower hydroplaning speeds because of the influence of tire footprint aspect ratio effects when their vehicles are lightly loaded.
Skid Resistance of Wet-Weather Accident Sites
Authors: Wambold JC , Henry JJ , Hegmon RR
Published: December 2008

A small-scale, wet-weather accident study was conducted in the years 1981 to 1983 as part of a wider study on pavement texture. The researchers were notified of wet-weather accident occurrences, and the skid resistance was measured as soon as possible after the accident, usually within one day, but never more than two days. During the study period, 79 such sites were tested, 21 of which had multiple accidents. All sites were tested with the ribbed and blank test tires. Similar tests were made on control sections within 1.6 km (1 mile) of the accident sites. These were selected to have geometric and traffic characteristics similar to those of the accident sites. As it turned out, the data base was too small to warrant definitive conclusions. Uncertainties about accident causation were reflected in the fact that the data from the control sites were not significantly different from those of the accident sites. The results, however, show a trend consistent with findings by other researchers. Skid resistance measured with the blank tire is not only lower than that measured with the ribbed tire, but is also better as a predictor of skidding accident potential. Wet-weather accident data from Florida were also analyzed, and the results reinforced this conclusion. The use of data from both the blank and the ribbed tire for pavement evaluation is recommended for future study.
Time-History Performance of Reference Surfaces
Authors: Whitehurst EA , Neuhardt JB
Published: December 2008

The paper describes briefly the construction of reference surfaces for use in skid trailer correlation at the Field Test and Evaluation Center for Eastern States and discusses in detail the performance of two of these surfaces over a nine-year period. The seasonal variation in skid number widely reported for pavement surfaces in service is clearly observed in these surfaces subjected to only test traffic. One of the surfaces having an epoxy cement overspray applied at the time of construction has retained essentially the same level of skid resistance throughout the nine years; the other, without the overspray, has experienced a continuing decrease in skid resistance. It is concluded that overspraying a surface with a wear-resistant membrane, which inhibits both loss and polishing of the surface aggregate, may result in a test pad, which will maintain its original skid number for a long period of time.
Development of Runway Rubber Removal Specifications Using Friction Measurements and Surface Texture for Control
Authors: Lenke LR , Graul RA
Published: December 2008

The phenomenon of runway touchdown zone rubber buildup is a potentially hazardous problem. Rubber buildup covers the runway surface and occludes the surface texture. This results in a reduced wet friction coefficient between the runway pavement and the aircraft tires. Methods and equipment are available for evaluating the wet friction coefficient; however, these methods are expensive and require highly trained personnel. Therefore, most airport and airbase managers rely exclusively on visual impressions of rubber buildup in lieu of quantitative friction measurements. Nonetheless, quantitative evaluation techniques are desirable for evaluating rubber buildup. A field evaluation experiment was developed to ascertain which of five selected texture measurement techniques are indicative of Mu-Meter friction values in pavement areas with rubber buildup. The five texture measurement techniques included two volumetric techniques for determining average texture depth, ASTM Test Method for Measuring Surface Macrotexture Depth Using a Sand Volumetric Technique (E 965) (sand patch) and the silicone putty test, two methods of rating the pavement microtexture, the Penn State (PTI) drag tester and the chalk wear tester, and stereophotography. This field experiment was designed to provide quantitative methods for ascertaining rubber buildup and removal requirements. Predictive models were established for estimating friction levels using texture measurements but were found to be too variable for specification implementation. Therefore, Mu-Meter friction was used in developing contract specifications for runway rubber removal.
The Most Complex Tire-Pavement Interaction: Tire Wear
Authors: Veith AG
Published: December 2008

Tire wear is the result of frictional work in the tire-pavement interface that is generated when tread surface elements go through a frictional force-slip cycle during each passage through the footprint. This review focuses on the nature of the two contacting materials in the treadwear process: the tread rubber and the pavement aggregate. To place the unique performance characteristics of rubber in their proper perspective, some text material is devoted to a brief review of the wear of materials in general and to the key role that visco-elastic behavior plays in the rubber-pavement contact.

Laboratory abrasion testers of various sorts have proven to be valuable in investigating rubber wear mechanisms, and they are reviewed, citing both the technological and the theoretical approaches. A general background on tire wear is presented by the use of a simple wear equation. Next the role of the two contacting surfaces is examined: the pavement aggregate and the tread rubber. The key pavement element of in the tread-wear process is the microtexture, that roughness of surface in the 10−2 mm range. Several characteristics of the tread rubber are important: the glass transition temperature, the reinforcement system (carbon black), and the general resistance of the rubber to friction induced (chemical) degradation. The influence of two of the three known external (to the tire) treadwear factors, frictional or tractive tire force intensity and “ambient-tire” temperature, are next examined. (The third external factor is the pavement microtexture.) Finally some brief information is presented on the actual loss mechanism of tread rubber principally by way of microscopic examination of worn tread surfaces and the morphology of abraded rubber particles.
Diagonal Wear Predicted By a Simple Wear Model
Authors: Shepherd WK
Published: December 2008

Diagonal wear on tires is a significant problem that can cause noise and vibration, and reduce the useful life of the tire. A wear model is used to show how diagonal wear can develop across the tread under certain conditions of toe and camber on a nondrive axle.

In a simple wear model, tread wear is taken to be proportional to abrasion and sliding length. Triaxial stress measurements made in the laboratory on the tread blocks of rolling tires provide data for the wear prediction model. Under nonzero toe and camber the magnitude of the predicted wear is increased and its pattern becomes diagonal; a higher wear rate is predicted near the leading edge of contact on one side of the tire and near the trailing edge on the opposite side. This prediction agrees with the diagonal wear pattern seen on tires run on the road at similar toe and camber settings.
Cleaning Efflorescences from Masonry
Authors: Gauri KL , Holdren GC , Vaughan WC
Published: December 2008

Salt efflorescences attack masonry in all parts of the world, but in the arid regions they are the major cause of masonry decay. The efflorescences crystallize repeatedly from saturated solutions and become hydrated, generating, in the confined pore space and under surface crusts, pressures large enough to overcome the strength of the masonry material.

Common methods for removing these salts are washing with water and application of surface-active poultices. These methods have their shortcomings: the first tends to transport salts into deeper regions by capillary action while removing some salts from the surface; the second method, besides being highly cumbersome, may result in masonry damage due to the salt crystallizing at the poultice-masonry interface.

This paper describes two suction techniques, one of which appears to eliminate these shortcomings while promising maximum removal of salt from large surfaces in the shortest possible time.
A Case Study of the Cleaning and Conservation of Marble at the Schenectady, New York, City Hall
Authors: Waite JG , Cheng RJ
Published: December 2008

The Schenectady, New York, City Hall was designed by McKim, Mead, and White, Architects and constructed in 1930–1931. In recent years, severe deterioration of the exterior marble architectural elements was observed by city officials. As a result of this concern, a study was undertaken to analyze the causes and extent of deterioration, as well as methods for its arrest and control.

Investigation of the marble deterioration was carried out using the following equipment and techniques:

(a) optical microscope with photomicrographic dispersive staining capability,

(b) scanning electron microscope and computer-based energy-dispersive X-ray microanalyzer,

(c) ion chromatography,

(d) electron microprobe, and

(e) environmental pollutants data.

Based on this analysis, the following conclusions were drawn regarding the deterioration of the marble:

1. The deterioration of the marble is caused by a constant direct chemical attack by sulfuric acid. 2. Nitric acid has not played a major role in the deterioration of this marble. 3. Acid precipitations have not played a major role in the deterioration of the marble. 4. The major vehicle for attacking the marble is sulfuric acid produced continuously on wet surfaces by the heterogeneous oxidation of absorbed sulfur dioxide (SO2) in the presence of catalysts associated with the burning of fossil fuels.

As the result of these investigations, a major program for the cleaning and conservation of both the exterior and interior marble was prepared and put into effect. It consisted of the following actions:

(a) thorough cleaning of the exterior marble to remove gypsum crusts and sulfur using low-pressure water washing with the use of chemical cleaning agents in areas with severe deterioration, (b) cleaning of the interior marble using liquid cleaning agents and poultices, and (c) preparation of a long-term building conservation/maintenance/repair program for the City Hall to arrest future deterioration.
A Macrostereogrammetric Technique for Measuring Surface Erosion Losses on Stone
Authors: Winkler EM
Published: December 2008

Vertical aerial photograph stereoscopic pairs are the principal resource for making topographic maps and terrain profiles. Based on the same principle, close-up stereophotographs were taken of a strongly weathered surface of Georgia marble. Profiles were drawn of the now roughened surface, and the surface reduction was measured against inclusions of unweathered hornblende. Overlapping close-up photographs were taken at a 1:1 size ratio with a Canon macrolens on a nonautomatic Canon AT camera mounted on a sturdy Velbon-Mini tripod. With the optical axis perpendicular to the stone surface, light was provided by both a ringflash mounted in front of the lens and reflected natural light. An ultrafine-grained black and white film (Kodak Technical Pan, TP 2415) was used, printed onto 12.7 by 17.8-cm (5 by 7-in.) contrast paper for a 5:1 enlargement of the original surface.

A simple Abrams Heightfinder was attached to a small folding pocket stereoviewer with about two- to three-power magnification lenses. The accuracy of the optical height measurements was about ±0.1 mm, based on comparison with measurements employing a needle-point depth micrometer.

The method described here is applied to the comparison of uncleaned with cleaned stone surfaces in terms of both surface shape and surface reduction.
The Concept of Total Building Performance and Building Diagnostics
Authors: Hartkopf VH , Loftness VE , Mill PAD
Published: December 2008

This paper introduces the concept of total building performance and the diagnostic tools for measuring and assessing this performance. It emphasizes the need: (1) to fully address the fundamental building performance mandates of thermal comfort, acoustic comfort, air quality, lighting comfort, spatial comfort, and building integrity; (2) to define their physiological, psychological, sociological, and economic limits of acceptability; and (3) to clarify their relationships with each other. Integrated within the building delivery process, these performance mandates and the associated diagnostic measurement and assessment tools suggest new quality assurance procedures for providing suitable and reliable conditions for occupancy comfort in new as well as in existing buildings.
Promoting Energy-Efficient Rehabilitation and New Infill Construction in the Inner City
Authors: Hartkopf VH , Loftness VE
Published: December 2008

During the past decade, major technical advances were made in energy conservation and in the use of alternate energy sources for residential construction. At the same time, the problem of rising energy costs has increased for large segments of the population, offering an unprecedented stimulus for energy-efficient construction practices. Nonetheless, the actual introduction of the new energy technologies into the planning, design, construction, and use of housing today still remains surprisingly unsophisticated and often is localized to new middle-class suburbs. This paper introduces an inner-city case study and demonstration project in Pittsburgh, Pennsylvania, that has attempted to penetrate these problem areas by demonstrating the political, economic, social, and technical reality of major energy savings afforded by inner-city rehabilitation and infill construction. To promote the introduction of the available new materials and energy technologies into the existing housing development process, the project team has developed workbooks of relevant guidelines, targeted at key decision-making groups: politicians and community officials; financiers, appraisers, and developers; designers and builders; and owners and renters.