bluuebunny/crossref_metadata_2025 huggingface dataset:
Identifying Segregation in Hot Mix Asphalt Pavements Using Rolling Nuclear Gage Measurements and Infrared Imaging
Authors: Stroup-Gardiner M
Published: February 2009

Previous research indicated that density, gradation, and asphalt content change due to segregation. A rolling nuclear gage capable of measuring both density and hydrogen count was evaluated for its ability to detect and measure both density and asphalt content. Eight projects (four recently constructed pavements and four during construction) were used to evaluate this instrument. Longitudinal density profiles were obtained for each project at transverse quarter points across the lane. Additional testing included infrared thermography and traditional destructive testing of cores.

Visual observations of texture differences were used to identify areas with no, low, medium, and high levels of segregation. At least three core locations were then identified from each of these areas; cores were taken always from the longitudinal paths tested with the nuclear gage. Cores were used to determine changes in air voids, asphalt content, aggregate gradation, and mix stiffness as a result of the various levels of segregation.

Results indicate it was difficult to use air voids alone to detect and measure segregation, regardless of how densities (air voids) were determined (i.e., nuclear density or core properties). The rolling nuclear density measurements showed that while densities may be uniform longitudinally, there were significant differences in densities transversely for several projects.

A second type of temperature segregation was found using this gage in combination with the infrared thermographs. During paving operations, the paver may be stopped to change or wait for the haul truck or to adjust the equipment. The mix immediately behind the paver cools off but cannot be compacted since the paver is in the way of the roller. This results in a localized transverse region of very low density.
Remedial Sealant Procedures for Fixed Glass and Curtain Walls
Authors: Beers PE , Yarosh KF
Published: February 2009

A commonly prescribed remedy for fixed glass (non-operable windows) and curtain walls that are experiencing water leakage is to install new exterior sealants throughout the system. This is commonly referred to as “wet sealing.” This method is commonly used on both new construction with water leakage problems and existing construction with aged sealants. Unfortunately, this repair solution is not always as easy as it sounds as there can be several complex details that must be addressed.

When “wet sealing,” the design concept of a system that was originally designed to collect and drain water is changed to a barrier system. With a barrier system, the concept is that all water will be shed at the exterior surface. Accordingly, if any water were to penetrate the outside face, it will be trapped inside the assembly. Therefore a retrofit that stops less than 100% of the water will not function.

This paper will present the factors to evaluate when considering a “wet seal” application. It also includes a discussion about how to properly seal various types of joints when “wet sealing.” Finally, other considerations that may affect the performance and longevity of the wet seal will be outlined.
An Improved Capping Technique for Excavatable Controlled Low Strength Material Compressive Strength Cylinders
Authors: Sauter HJ , Crouch LK
Published: February 2009

ASTM D 4832: Standard Test Method for Preparation and Testing of Controlled Low Strength Material (CLSM) Test Cylinders currently permits three types of capping for CLSM cylinders: sulfur mortar (ASTM C 617), gypsum plaster (ASTM C 617), and unbonded neoprene restrained by rigid retainers (ASTM C 1231). These cappings were developed for portland cement concrete (PCC) cylinders and all produce good estimates of PCC potential strength. However, these cappings are inappropriate for excavatable CLSM cylinders. Sulfur mortar and gypsum plaster methods often result in cylinder damage during capping due to the low strength of excavatable CLSM cylinders. The recommended 50 to 70 durometer neoprene pads are far too stiff at low stress levels, which are common in testing excavatable CLSM cylinders. The neoprene pads essentially act as a rigid plate rather than a capping material. The authors developed an unbonded capping system using a much softer neoprene that is more malleable at lower stress levels.

To evaluate the effectiveness of the new capping system, ten batches of an air-entrained and ten batches of a non-air-entrained excavatable CLSM were produced. Each batch was approximately 0.0453-m3, allowing 20 100-by-200 mm cylinders as well as flow consistency (ASTM D 6103) and gravimetric air tests (ASTM D 6023). Five pairs of cylinders were tested at 7 days and five pairs at 28 days. At each age, one pair was capped with each of the following materials: sulfur mortar, gypsum plaster, 50-durometer neoprene, nothing, and the new softer neoprene unbonded capping system.

The average 28-day compressive strength of the cylinders using the proposed capping system was 275 kPa (39.83 psi) for non-airentrained and 345 kPa (50.01 psi) for the air-entrained mix design. The proposed capping system was not significantly different than the sulfur mortar or gypsum plaster. It was significantly superior to 50-plaster durometer neoprene and the no-cap technique.
Evaluation of the Autofrettage Effect on Fatigue Lives of Steel Blocks with Crossbores Using a Statistical and a Strain-Based Method
Authors: Badr EA , Sorem JR , Tipton SM
Published: February 2009

A problem of fundamental and industrial interest is the effect of autofrettage on fatigue lives and the structural integrity of engineering components. The component considered is a steel block containing crossbores, a situation found in many industrial applications such as the fluid ends of positive displacement pumps. Twenty-one steel blocks containing intersecting perpendicular crossbores were autofrettaged with pressures ranging from 79 to 172 MPa. The specimens were subsequently fatigue tested on a specially designed test facility under 53 and 69-MPa pressures. Statistical procedures based on analysis of variance were used to analyze the effect of the different autofrettage pressure levels on fatigue lives of specimens. The reverse plasticity criterion was also used to investigate the fatigue enhancement limit of the autofrettage process. Results of the statistical methodology correlated with results of the reverse plasticity criterion showed the existence of an “optimal” autofrettage pressure.
A New Assessment Method for the Bulk Modulus and the Poisson's Ratio of Porous Ceramics
Authors: Yeheskel O , Tevet O
Published: February 2009

A new assessment method for the elastic moduli of porous materials is proposed. This method is based on a linear correlation between the Young's and the shear moduli of a given porous material. It is shown that such a correlation prevails for ceramics (Al2O3,ThO2,andZnO) and for glass (SiO2) having Poisson's ratios of the solid bulk in the range of 0.15<ν0≤0.36. The outcome of the new assessment method is the use of either an elastic modulus or a sound velocity as the parameter for non-destructive assessment of the bulk and the Poisson's ratio of porous ceramics. These findings open a simplified route to quantitative non-destructive evaluation (QNDE) of the elastic moduli of porous materials.
A New Technique for Measurement of the Strength of Ceramic Shells in the Precision Casting Process
Authors: Reddy AC , Murti VSR , Jebaraj PM
Published: February 2009

This paper discusses the development of a new technique for measuring the strength of ceramic shells. In this technique, compressed air was passed into the ceramic shells and the bursting pressure was measured using a diaphragm pressure gage. The hoop stresses were calculated. The results of the new technique realistically match the actual failure rate of shells in the precision casting process.
Development of Small Punch Tests for Creep Property Measurement of Tungsten-Alloyed 9%Cr Ferritic Steels
Authors: Komazai S , Hashida T , Shoji T , Suzuki K
Published: February 2009

A small punch creep (SP-C) testing technique using miniaturized specimens has been demonstrated for evaluating creep properties and material deterioration due to thermal aging. This technique has been applied to tungsten-alloyed 9%Cr ferritic steels. Experimental results revealed that the overall shapes of the creep curves obtained from the SP-C tests were qualitatively similar to those obtained from conventional uniaxial creep tests and reflected closely the degradation of creep rupture strength of the materials. A correlation with uniaxial creep was also determined in terms of stress (load) exponent and apparent activation energy for creep deformation. The correlation suggests that the SP-C testing technique may provide a useful tool for evaluating degradation of creep properties for structural components in-service.
Repeatability Analysis of Road Roughness Measurements
Authors: Divinsky M
Published: February 2009

A roughness of the road profile as an inherent pavement surface characteristic is of importance in pavement management. Roughness measurements are used for dividing the road section into statistically homogeneous units, establishing the preferences for maintenance and rehabilitation, and in other aspects of pavement surface characterization. Roughness characteristics are variable, and the method of obtaining the measurements as well as equipment specifications have significant effect on the processing and interpretation of the results. The most basic aspect of measurement capability is repeatability, and the measurement system cannot be accepted without a relatively high level of repeatability. For the purposes of repeatability studies, paired series of roughness measurements have been collected at the Israeli Public Works Department at the same road section under the same conditions for the section, device, and operator. The results of the repeatability studies include descriptions of statistical peculiarities of roughness measurements for each profile involved in the analysis, mutual behavior of compared measurements, as well as repeatability characteristics of the measurement system.
Testing of Thermal Imagers for Nondestructive Thermal Testing Applications
Authors: Chrzanowski K , Fischer J , Gutschwager B , Wrona W
Published: February 2009

One of the important areas of application of commercial thermal imagers is nondestructive thermal testing. An analysis of two standards published by the American Society for Testing and Materials describing measurement procedures of the minimum resolvable temperature difference (MRTD) and the minimum detectable temperature difference (MDTD) was made in this paper. It was shown that in the case of modern thermal imagers, the measurement results of these parameters carried out according to the ASTM recommendations may be unreliable. Proposals to update the standards and to enable accurate measurement of the parameters mentioned above are presented. A laboratory setup for measurement of the MRTD and the MDTD that fulfills requirements of the proposals is described. Measurement results of the parameters for a modern commercial imager according to updated procedures are presented.

Erratum to this paper appears in 28(6).
An On-Line Correction Technique of Random Loading with a Real-Time Signal Processor for a Laboratory Fatigue Test
Authors: Li M , Wu Y-S , Xu B-H , Jia W , Zhao W
Published: February 2009

The authors present an application of the Solartron 1200 Real Time Signal Processor to correcting the on-line random loading in a fatigue test system. By inputting a power spectrum described by a data file to a computer, its corresponding random process may be simulated. Since the processor is connected with a computer, results of signal processing done by the processor are sent to the computer periodically during the test. The computer performs pattern matching using the correlation coefficient value (CCV) between a loading spectrum and its predetermined target. If a CCV exceeds its threshold, the old data file will be replaced with a new one and the random loading exerted on a specimen will be updated. When the new data file is obtained based on optimal control strategy, the updated loading spectrum will approach its target. Therefore, an electrohydraulic fatigue test system equipped with a real-time signal processor can realize an on-line correction of a random loading based on the target spectrum desired. Since this updating does not change the original software package and hardware of the system, the performance of the system and testing quality are safely improved.
Transverse Vibration of a Simply Supported Frustum of a Right Circular Cone
Authors: Murphy JF
Published: February 2009

Presently, there is no efficient mechanical method in the United States to sort small-diameter logs. This paper explores the problem theoretically using transverse vibration as one such method. The numerical solution to the frequency equation for the transverse vibration of a simply-supported frustum of a right circular cone is found. We refer to this solid as a tapered cylinder with constant taper. The numerical solution is found as a function of cylinder taper, and an approximation to the solution of the frequency equation for slight taper is presented and compared with the numerical solution. This simple yet accurate approximation is most useful to determine the tapered cylinder's flexural stiffness or modulus of elasticity by freely vibrating a simply supported tapered cylinder.
Effect of Zeolitization on Compaction, Consolidation, and Permeation Characteristics of a Lagoon Ash
Authors: Kolay PK , Singh DN
Published: February 2009

A common method of disposing of ash generated from coal-fired thermal power plants is wet disposal, where the ash is mixed with water to make a slurry and is disposed of in ash ponds or lagoons. Such a disposal system allows for ash-water interaction, and alkalis present in the ash react with water, leading to the formation of ash zeolites. Formation of zeolites alters the overall properties of the ash. Controlled laboratory experiments have been conducted on a lagoon ash to determine the effects of zeolitization on its physico-chemico-mineralogical properties. Further investigations have been carried out to demonstrate the effect of zeolitization of the ash on its geotechnical properties such as its compaction, consolidation, and permeation characteristics. Such a study is required for bulk utilization of the ash (as a fill material) where compaction, consolidation, and permeation properties are most important.
Evaluation of Density Gradients in Loaded Wheel Tester Samples
Authors: Cooley LA , Kandhal PS
Published: February 2009

The Asphalt Pavement Analyzer is a tool used to estimate the rutting potential of hot mix asphalt (HMA). This device is essentially the second generation of the Georgia Loaded Wheel Tester. It measures rutting potential by applying a moving wheel load to the surface of an HMA sample through a pressurized linear hose.

This study was conducted to evaluate the density gradients in samples compacted with methods common to the Asphalt Pavement Analyzer. Both beams compacted with the Asphalt Vibratory Compactor (AVC) and cylinders compacted with the Superpave Gyratory Compactor were included. In order to realistically compare the two modes of compaction, cylindrical specimens compacted with the AVC were also included.

Data accumulated from this study showed that the two compaction methods did produce different density gradients within samples. Vibratory compaction produced a density gradient where the highest density was at the top of the sample and subsequently the density was less toward the bottom of the sample. Gyratory compaction resulted in less density in the top and bottom of samples and more compaction in the middle of the sample.
Assessment of Misalignments in Some Selected Buildings in Jordan and Their Structural Effects
Authors: Abdel-Halim MAH , Obaidat MT
Published: February 2009

A field survey was performed to assess horizontal and vertical misalignments and their structural effects in some selected buildings in Irbid City, Jordan. Fifty-two building units were selected as representative of the construction practice of residential buildings in Jordan after the Gulf War during the nineties. Buildings in the inventory were low-rise with one to four stories above ground. Story height ranged typically from 2.80 to 3.30 m. Field measurements for misalignments in the exterior elements of twentyone buildings were collected. Twelve of these buildings have concrete-backed stone masonry walls that serve as bearing walls, and nine buildings have skeletons which serve as reinforced concrete frames in-filled with hollow concrete blocks. Also, field measurements for misalignments in the interior elements of thirty-one buildings with skeletons of reinforced concrete frames filled in with hollow concrete blocks have been collected using the concept of the intersection algorithm.

Average values of measured misalignments for every type of construction are compared with the tolerances according to the Jordanian Standards, General Technical Specifications for Buildings, and ACI Standards. All measured misalignments exceed the tolerances in both standards except for the vertical alignment of the interior reinforced concrete frames filled in with hollow concrete blocks. The maximum values for the ratio between the measured misalignments and the tolerances were in the exterior concretebacked stone masonry walls, which reached 31.5 for the horizontal misalignment, and 3.4 for the vertical misalignment, according to the Jordanian Code. The reason for the different ratios between the interior and the exterior misalignments is due to more difficult environmental conditions for outside construction compared with inside construction. The value 3.4 for vertical misalignment compared with 31.5 for horizontal misalignment reflects the importance of using checking and surveying equipment (such as level and plumb) for every stone course (25 cm height), while lines and other checking equipment are used for horizontal distances which range between 12 and 15 m.

Moreover, misalignment sensitivity analysis was carried out for a typical reinforced concrete frame, which consisted of three spans continuous beam and four-story height, for the purpose of studying its effect on the static actions in the plane frame. Results indicated that horizontal misalignments have negligible effect on the static actions, however, vertical misalignment starts to have an effect at a value of 2.5% (e.g., at 3% vertical misalignment and 2.5% horizontal misalignment the required ratio of steel in the column has increased from 0.0100 to 0.0219).
Condition Monitoring of a Water Hydraulic Cylinder by Vibration Analysis
Authors: Tan ACH , Chua PSK , Lim GH
Published: February 2009

This paper attempts to lay some groundwork on reciprocating machines with particular emphasis on a water hydraulic cylinder. The objective is to diagnose a worn-out piston seal by means of vibration analysis. Pulsation theory is used to explain the harmonics produced in reciprocating machines. The cylinder piston seal was removed to simulate actual wearing of the seal. This mod ified machine was tested for its vibration signals and compared against the “healthy condition” state under some loading. LabVIEW® was used as the software interface. Results show that removing the piston seal caused an increase in magnitude at a fundamental fault-dependant frequency in the amplitude spectra.
Method-Specific Precision and Bias Relationships Developed from Data Submitted During USEPA Wastewater Laboratory Performance Evaluation Studies
Authors: Britton PW
Published: February 2009

This paper documents the process used the United States Environmental Protection Agency (USEPA) to estimate the mean and standard deviation of data reported by in-control wastewater laboratories during Water Pollution (WP) studies. This process is then applied to the data reported for each specific sample, analyte, and method in ten WP studies and linear relationships between the mean response and true analyte concentration, and between the interlaboratory standard deviation of responses and true analyte concentration, are presented. Such relationships can be invaluable as background information for anyone who must conduct an interlaboratory study using the same methods to analyze similar interference-free samples, or who must evaluate the analytical quality of such data.
Repeatability and Bias of Two Walkway Safety Tribometers
Authors: Powers CM , Kulig K , Flynn J , Brault JR
Published: February 2009

Falls resulting from slips on walkway surfaces are a significant source of injury in society. To measure friction between the floor and the shoe, various types of tribometers and ASTM standards have been developed to assess walkway slip-resistance with the goal of improving pedestrian safety. The purpose of this study was to determine the repeatability and bias of the PIAST and VIT tribometers under both dry and wet conditions. Both devices were tested on an AMTI force platform over a wide range of angles. Bias was assessed by comparing the tribometer slip resistance reading to the actual Fx/Fz ratio measured by the force plate, while reliability was established by evaluating the ability of the tribometers to reproduce Fx, Fz, and the Fx/Fz ratio. Both tribometers demonstrated high degrees of bias and repeatability under both wet and dry conditions; however, each measured different slip-resistance values for the same surface. Further study should be directed at establishing which tribometer best simulates initial foot contact during gait with respect to measuring slip resistance.
On the Application of the Indirect Compliance Measurement Technique to Flexure Specimens Containing a Chevron Notch
Authors: Sarrafi-Nour GR , Coyle TW
Published: February 2009

Various fracture tests employing chevron-notched flexure specimens require accurate measurement of the specimen loading-point compliance at least through the achievement of the maximum load. Conventionally this compliance is determined by monitoring the center-point deflection on the specimen and then correcting the measured displacements for the compliance of the test setup, determined through separate calibration tests. A simple and accurate indirect determination of the compliance under flexure load condition, which is not affected by the compliance of the test setup used for fracture testing, was introduced previously. This method has been verified for flexure specimens containing throughthickness cracks. The present work deals with the application of the indirect compliance measurement method to chevron-notched flexure specimens. The original governing relation, previously verified for a specimen with a through-thickness crack, is modified based on finite element analysis results so as to be applicable to the chevronnotched specimens. After modification, this method is shown to lead also to accurate determination of the loading-point compliance in tests involving chevron-notched specimens.
Environmental Degradation of Natural Rubber Latex Gloves: The Effects of Elevated Temperature on Tensile Strength
Authors: Walsh DL , Chwirut DJ , Kotz RM
Published: February 2009

Various styles of latex gloves were oven-aged for 7, 14, and 21 days at 70°C and then subjected to tension testing per ASTM D 412. Five of seven powder-free glove styles exhibited dramatic decreases in tensile strength after 7 to 14 days at 70°C, with total decreases in tensile strength ranging from 70 to over 90% after 21 days of aging. These five styles were examination gloves that were later confirmed to be chlorinated. In contrast, a chlorinated surgical glove, a non-chlorinated examination glove, and all of the powdered gloves (examination and surgical) subjected to the same conditions exhibited total decreases in tensile strength ranging from 0 to 25% after 21 days. These results suggest that chlorination, a process commonly used in the manufacture of powder-free gloves, may have detrimental effects on the ability of natural rubber latex to retain its barrier integrity after exposure to severely elevated temperatures.
Modeling of Vibratory Cavitation Erosion Test Results by a Weibull Distribution
Authors: Meged Y
Published: February 2009

The rate of mass loss in vibratory cavitation erosion tests varies with time. As a consequence, this process is treated empirically. It is suggested by the author that the cumulative mass loss-time curve test results can be represented accurately by the Weibull cumulative distribution function. This model was verified for 26 tests of nine metals. Among these metals is Ni 200, which is a standard reference material for erosion tests. This model allows treating the results of vibratory cavitation erosion tests analytically, thereby obtaining invaluable information from the test data.
In Situ Shear and Compression Tests in Ancient Stone Masonry Walls of Tuscany, Italy
Authors: Chiostrini S , Galano L , Vignoli A
Published: February 2009

The present paper reports methods and results of an extensive experimental project performed to assess the mechanical characteristics of ancient stone masonry walls of Tuscany (Italy). Some relevant considerations concerning the determination of common design shear strength parameters via experimental test results are also presented. Results from 22 in situ tests performed on nine large-scale stone masonry panels are reported. Test panels were selected as part of shear walls in six different old masonry buildings in the northern part of Tuscany so as to represent a reliable sample of the most common masonry types in this region. In situ tests were carried out according to experimental schemes for vertical compression, shear compression, and diagonal compression. After the first test, several panels were repaired and reinforced by means of cement mortar injections (full cement grouting) or reinforced concrete (RC) jackets, and then tested again to determine the effectiveness of the intervention. Particular attention was then devoted to evaluate the referential shear strength τk of these masonry assemblages in the original state. To this purpose, a fitting process for experimental data was used, adopting two different schemes for interpretation of the shear strength of masonry (the Coulomb and the Tumsek-Cacovic equations). The results from this work have shown that the Turnsek-Cacovic equation gives a better fit to experimental data than the Coulomb equation, especially for medium- and poor-quality masonry walls. Finally, conclusions are presented noting the difference between shear strength values calculated from fitting the data from test results and the values suggested by European and Italian standards.
Method of Measuring the Shear Strength of Wood by the Asymmetric Four-Point Bending Test Using a Notched Beam Specimen
Authors: Yoshihara H , Ohhata O
Published: February 2009

We measured the shear strength of wood by the asymmetric four-point bending test using notched beam specimens of Todomatsu (Japanese fir, Abies sachalinensis Fr. Schmidt). The notches were cut on both longitudinal-tangential (LT) planes along the neutral axis, and the load was applied asymmetrically on the longitudinal-radial plane to obtain the shear strength of the LT plane. In the tests, the notch depth and span-to-thickness ratio, which was defined as span/depth ratio, varied and the influence of specimen configuration was examined. Independently of the bending tests, block shear and Iosipescu shear tests were performed and the shear strengths obtained were compared with those obtained by the bending tests. When the specimen had a proper configuration, the value of shear strength was stable over a wide span/depth ratio range and was close to that obtained by the Iosipescu shear test. Hence, we think that the asymmetric four-point bending test using a notched beam specimen is promising for evaluating the realistic shear strength of wood.
A Review of Watermarking Techniques: Applications, Properties, and Domains
Authors: Trichili H , Bouhlel M-S , Kamoun L
Published: February 2009

With the expansion of the Internet an increased amount of digital information, such as documents, images, and audio and video data has become available to a large number of people. Since the digital network is often used to offer digital media for profit, there is a strong need for copyright protection and a considerable interest in methods for inserting in a multimedia document a visible, or preferably invisible, mark to identify the owner. This article provides an overview of watermarking properties, and an evaluation of different embedding domains besides different applications. A survey of them and their respective requirements is presented.
Comparison of Fine Aggregate Uncompacted Voids Content Measured by the ASTM C 1252 and the VTM-5 Devices
Authors: Rismantojo E , Haddock JE , White TD
Published: February 2009

As part of the National Cooperative Highway Research Program Project 4–19(2), a series of uncompacted voids tests was performed using the ASTM Test Methods for Uncompacted Void Content of Fine Aggregates, C 1252, and the Virginia Department of Transportation VTM-5 test devices. Comparisons between the uncompacted voids measured by the two devices were made by using five different measurement methods on each of six different fine aggregates. The effects of test procedure and/or device, and their interactions with particle size on the measurement of uncompacted voids were also examined. As expected, the findings indicate that the graded sample of ASTM C 1252, Method A produces a significantly lower result for uncompacted void content than do the other four methods. However, the five test methods are significantly correlated. Furthermore, while there appears to be an interaction between test device and particle size, this effect is negated when the graded sample of ASTM C 1252, Method A is used.
A New Dynamic Wind Load Cycle to Evaluate Mechanically Attached Flexible Membrane Roofs
Authors: Baskaran A , Chen Y , Vilaipornsawai U
Published: February 2009

In North America, at present, no test procedure exists for certifying roofing systems under dynamic wind loads. To develop such a dynamic test procedure, the National Research Council of Canada (NRC) formed an industry-based consortium during 1994. The consortium is known as the Special Interest Group for Dynamic Evaluation of Roofing Systems (SIGDERS). This paper reports SIGDERS' progress on dynamicload cycle development. Wind tunnel investigations were carried out using two flexible roofing membranes: poly(vinyl chloride) (PVC) and ethylene propylene diene monomer (EPDM). Using the wind tunnel pressure records as source data and comparing the membrane responses of PVC with EPDM, SIGDERS developed a dynamic load cycle. With input from industries, building owners, and roofing associations, the developed load cycle has been generalized and extended to evaluate the ultimate strength of flexible membrane roofs. To validate the newly developed load cycle, several membrane roofing systems were investigated and then reported separately. The SIGDERS load cycle in a laboratory mimics failure modes similar to those observed in the field.
Development and Evaluation of a Biaxial Tensile Tester for Fabrics
Authors: Ghosh TK
Published: February 2009

At the Nonwovens Cooperative Research Center (NCRC), North Carolina State University, a prototype instrument has been designed to measure fabric behavior under biaxial force. The system is equipped with a segmented and self-adjusting clamping system designed to apply uniform finite strain in the sample without undesirable boundary effects. The control system is designed to allow tests to be performed under a constant force-ratio or a constant extension-ratio condition. The designs of the clamping and control systems of the instrument have been evaluated by testing a number of spunbonded nonwoven fabrics. The results show a significant influence of biaxial deformation on the force-extension characteristics of fabrics.
Comparison of Returnable Paper and Plastic Corrugated Packaging Trays for the United States Postal Service
Authors: Singh SP , Walker R , Close D
Published: February 2009

This study provides a comparison of paper and plastic corrugated materials that are used for packaging. The test containers were mail trays used by the United States Postal Service. The test methods consist of performing an accelerated test in a warehouse facility that closely simulates the everyday handling characteristics encountered by these trays in postal facilities. The results also compared differences in material-recycled content and fabrication processes. The results show that the reusable plastic corrugated trays performed 2.5 to 3 times better than similar types of reusable paper corrugated trays.
Permeability and Consolidation Behavior of Fly Ashes
Authors: Pandian NS , Balasubramonian S
Published: February 2009

A knowledge of permeability and consolidation is essential in a number of engineering problems such as settlement, seepage, and stability of the structures. Since fly ash is used very widely for several geotechnical applications, there is a need to understand its permeability and consolidation behavior. This paper presents a detailed study conducted on two Indian fly ashes. It brings out the role of chemical composition (free lime) on the permeability and consolidation behavior of fly ashes. It is found that the permeability values computed based on grain-size distribution agree well with those obtained based on test data.
A Powerful New Tool for Testing Adhesives In Situ
Authors: Gegner J , Öchsner A
Published: February 2009

The thick-adherend tensile-shear test of adhesive technology is improved in the experimental part and supplemented with a new computer-aided evaluation method. Stepped substrates ensure a more uniform stress state by increasing the stiffness of the assembly. In order to minimize the influence of the adherend deformation, which is taken into account by a finite element calculation, the total displacement of the joint was measured directly at the overlap zone. For this purpose, two extensometers with strain gages were attached to each side of the specimen at three reference points. In this way, realistic shear data were obtained from the determined stress-strain diagrams. The evaluation procedure was also improved by developing a numerical test simulation technique that allows the computation of Young's modulus. Steel substrates and an anaerobic adhesive were used. The influences of both the test temperature and the bond gap on the mechanical properties of the joint were investigated.
Effects of Recording Parameters on Power Density Spectra in Transport Vibration Measurement
Authors: Singh SP , Sittipod S
Published: February 2009

The variability that exists in the memory and the programmed recording parameters in various types of data recorders has not been well defined. This study investigated the effect of these differences on the final power spectrum density (PSD) generated by environmental data recorders (EDRA). Random vibration levels from both an electrohydraulic vibration table and a 40-ft truck shipment were measured using two types of data recorders. The PSD levels, both numerical and graphical, developed from various recording control parameters were compared.
Proper Selection of the Stiffness of the Disk Spring Pile Cap in Pile Driving
Authors: Zhou L , Zhou X
Published: February 2009

This article analyzes the relationships among the stiffness of the composite disk spring pile cap, the pile penetration, and the dynamic stress within the body of the pile, in pile driving. The range for proper matching between the stiffness of the composite disk spring pile cap and the stiffness of the driven pile is determined through optimization analysis of the pile-driving process.
California Bearing Ratio Behavior of Soil/Fly Ash Mixtures
Authors: Pandian NS , Krishna KC , Sridharan A
Published: February 2009

Fly ash is a hyproduct of the combustion of pulverized coal in thermal power plants. Energy and environmental considerations over the coming years point to greater use of coal and hence a further increase in the quantity of fly ash. Geotechnical and chemical characterization of fly ash and its interaction behavior with soil is likely to provide viable solutions for its large-scale disposal and utilization. Concerted efforts have been initiated in the laboratory to understand the effect of fly ash addition on the California Bearing Ratio (CBR) values of black cotton soil both for unsoaked and soaked conditions. The study indicates that CBR values of black cotton soil/fly ash mixtures increase up to an optimum fly ash content wherein fly ash acts as a coarser material. The CBR values decrease beyond this optimum fly ash content and again increase to an optimum value wherein black cotton soil acts as a binder.
Formation of Shear Bands in Model Ground Composed of Aluminum Rods Beneath a Footing
Authors: Yoshida N , Bettou T , Wakita M
Published: February 2009

In this study, a series of bearing capacity tests were carried out on a model ground composed of aluminum rods in order to investigate the initiation and development of shear bands during loading. This paper describes the test apparatus, the methods of testing and data treatment, and some of the test results. Two types of model grounds were prepared depending upon whether the aluminum rods used were single-diameter or two different diameters. During the loading test, by utilizing both front and back of the test apparatus, detailed observations were made on the global deformation of the model ground, on the translational and rotational movements of selected aluminum rods, and on the change of void ratio. It is shown that, in the case of the single-diameter aluminum rods, the slip surface was observed and that dilatancy behavior was noted at the boundary. In the case of the aluminum rods with two different diameters, discontinuous shear bands defining a so-called plastic flow zone were observed, which were initiated at the bottom corners of the footing and extended diagonally downwards. The rotational behavior of the rods differed inside and outside the plastic flow zone, particularly near the boundaries.
J-Integral Evaluation of Single-Edge Notched Specimens under Mixed-Mode I/II Loading
Authors: Donne CD , Pirondi A
Published: February 2009

Standard test methods of mixed-mode fracture toughness still do not exist, even though a decrease of fracture toughness with increasing Mode II (shear components) has been observed for a number of steels. A J-estimation scheme for mixed-mode loaded single-edge notched specimens is therefore developed in this paper. In accordance with the ASTM Standard E 1820-99, the evaluation of the plastic part of J is based on the measurement of the dissipated plastic energy weighted by a ηpl-factor. Two different approaches for the ηpl-factor are derived. Factors from both showed good correlation with finite element calculations for the specific case of a compact-tension-shear specimen (C(TS)), Finally, a simple clip gage setup for the measurement of the crack-opening displacements needed for the evaluation of the dissipated plastic energy is presented. The problem of the qualification of the mixed-mode crack initiation data is not specifically addressed, but some general comments on this topic are given at the end of the paper.
Falling Head Hydraulic Conductivity Tests in a Geotechnical Centrifuge
Authors: Singh DN , Gupta AK
Published: February 2009

Permeability of geomaterials is the most important parameter involved in the assessment of advection of groundwater and contaminants in the subsurface and for the design of barriers to contain hazardous wastes. Evaluation of the permeability of soils by employing a geotechnical centrifuge, where centrifugal acceleration is used to simulate the prototype conditions, is an area of current research interest. This paper presents a working methodology that can be employed for measuring the hydraulic conductivity of compacted fine-grained soils in a geotechnical centrifuge. Two different hydraulic conductivity setups have been developed for silty sand and clays. The paper also studies the effect of sample length, the limiting acceleration levels, and the time of centrifugation on the hydraulic conductivity measurements.
Model Tests by Centrifuge of Soil Nail Reinforcements
Authors: Zhang J , Pu J , Zhang M , Qiu T
Published: February 2009

Soil nailing is an in situ technique to reinforce slopes in the vadose zone where the soil is partially saturated. In this research, model tests of soil nailing on steep cuttings of an unsaturated silty clay were performed using a centrifuge. The results show that soil nailing can greatly increase the stability of cuttings. The length and density of soil nails have significant effects on the deformation behavior and failure mechanism of the soil-nailed structure. When the ratio between the maximum nail length and the excavation depth (L/H) was 0.32 or 0.34, the model slope was unstable with a prototype spacing less than 1.8 m. However, when the L/H ratio was 0.48 or 0.80, the model slope was substantially stable against global failure under the same spacing. External failure occurred in nailed structures with densely reinforced shorter nails; the prototype spacing was less than 1.29 m and the length ratios were 0.32 and 0.34. Internal failure occurred in nailed structures with sparsely reinforced longer nails: the prototype spacing was 3.6 m and the length ratio was 1.0. The failure surfaces of the nailed cuttings were deeper than that of the cutting without reinforcement.
Evaluation of the Elevated Temperature Creep Strength of Three Lead-Free Solder Alloys in Soldered Joints
Authors: Shepherd D , Hagwood C , Fields R
Published: February 2009

Amendments to the Safe Drinking Water Act mandated that soldered joints used in potable water systems be free of lead. In addition to lead contents, allowable pressures used in potable water systems are directly related to the elevated temperature creep strengths of the soldered joints. The National Institute of Standards and Technology (NIST) and the Copper Development Association (CDA) investigated the stress rupture behavior of leadfree soldered joints at four temperatures and various applied stresses. An extensive statistical analysis involving maximum likelihood techniques was used to generate estimated threshold stresses (below which failure in the soldered joints did not occur) as a function of composition and temperature. The results of that study for three solder alloys are given.
The Calibration Functions of the Arc-Shaped Bend Specimen
Authors: Donoso JR , Basáez F , Landes JD
Published: February 2009

The geometry functions of the Common Format Equation developed by Donoso and Landes were evaluated for the arc-shaped bend specimen. A(B), with a span-to-width ratio S/W of 4 and r1/r2 = 0.95. The specimen geometry functions, Gel = C*BW(b/W)μ, and Gpl = CBW(b/W)m, in the elastic and the plastic range, respectively, were numerically computed with the aid of a two-dimensional, nonlinear, plane strain finite element analysis. The elastic solution, in the form of an elastic compliance, was compared to values obtained in the concise format from the K-solutions of ASTM E 1290. The plastic solution, on the other hand, was compared with available experimental values. The numerical results showed μ = ηe1 = 2,1185 and m = ηpl = 2,0894 for the A(B) specimen analyzed. As is the case with other bend-type specimen geometry, μ ≈ m, which indicates that the J-integral may be computed as one single integral form, in terms of total displacement. For this, it is proposed to use as eta values (clastic and plastic) for the A(B) specimen, the same values of μ derived from the K-solution, dependent on the size ratio r1/r2.
Service Temperature Characterization of Polytetrafluoroethylene-Based Gaskets
Authors: Bouzid A-H , Derenne M , Marchand L , Payne JR
Published: February 2009

Gaskets based on polytetrafluoroethylene (PTFE) are used extensively in bolted flanged connections, especially in difficult chemical process plant applications where blowouts due to excessive bolt load loss are of major concem. The determination of their service temperatures requires the characterization of their short- and long-term creep relaxation resistance. An experiment-alanalytical procedure has been developed to determine a recommended service temperature for PTFE-based gaskets. Based on an improved version of the Hot Blowout Test (HOBT) in which thermal cycling has been incorporated, the procedure quantifies the short-term hot relaxation resistance, and the margin of safety against an in-service blowout. The improved HOBT test provides an excellent tool for the selection of blowout-resistant PTFE gaskets for difficult service.

Currently, the procedure estimates the cooldown load loss due to the thermal contraction difference between the gasket and the flange, based on a rough estimate of the gasket thickness and the coefficient of thermal expansion and their vanation with temperature. The proposed procedure provides not only a better estimation of the gasket thickness but also accounts for thermal ratcheting and the temperature lag between flange and bolts.
Static Axial Behavior of Some Typical Restrained Pipe Joints
Authors: Meis R , Maragakis M , Siddharthan R
Published: February 2009

This paper presents the results of a static testing program designed to determine the axial stiffness and strength characteristics of some typical restrained pipe joints. Pipelines have suffered damage and failure from past earthquakes and are vulnerable to seismic motions. A vast majority of the pipeline failures have occurred at unrestrained pipe joints due to pull-out, and therefore, the effectiveness of restrained pipe joints needs to be examined and their response to earthquake motion needs to be assessed in order to help mitigate potential damage. This paper also suggests methods to use test results for pipeline network analysis and for risk assessment procedures.
Expression for the Dynamic Yield Stress from Instrumented Dynamic Tear Specimens and Plastic η-Factor for Three-Point Bend Specimens: Results for AISI 308 Weld and AISI 316 Stainless Steels
Authors: Sreenivasan PR , Ray SK , Mannan SL
Published: February 2009

An empirical expression for computing the dynamic yield stress, σyd, from the general yield load, PGY, of dynamic tear (DT) specimens has been derived by comparing the results from instrumented drop-weight/impact tests of DT and Charpy V-notch (CVN) specimens of AISI 308 weld and AISI 316 stainless steels. This is based on the following assumptions: the functional expression relating σyd to PGY is the same for both DT and CVN specimens except for a dimensionless proportionality constant: and σyd from both the specimens has the same value. Plastic η-factors obtained by analyzing instrumented DT test results are also presented. The work reported earlier by the authors based on instrumented CVN and precracked Charpy specimen test results showed the dependence of the plastic η-factor on the crack aspect ratio; the present results indicate that the plastic η-factor shows an additional specimen size dependence. However, the new estimates based on the larger size specimens are only slightly larger than the lower-bound estimates reported earlier, but much below the upper-bound curve reported at the same place. Similar size dependence has been reported in the literature.