bluuebunny/crossref_metadata_2025 huggingface dataset:
The Significance of Nonlinear Motion in the Wear Screening of Orthopaedic Implant Materials
Authors: Wang A , Polineni VK , Essner A , Sokol M , Sun DC , Stark C , Dumbleton JH
Published: February 2009

Linear reciprocating pin-on-plate-type wear testing has been a standard technique for the screening of orthopaedic implant materials since the early 1980s. This investigation compares a wear screening technique based on linear motion with a modern hip joint simulator based on multi-axial motion. Two groups of differently sterilized UHMWPE samples were tested. The first group of samples was sterilized by ethylene oxide (EtO) gas that caused no structural changes in the UHMWPE. The second group of samples was sterilized in nitrogen by gamma-irradiation and then subjected to a stabilization treatment that resulted in a significant level of crosslinking in the UHMWPE. When tested on the linear reciprocating wear machine, the EtO sterilized specimens (non-crosslinked linear polyethylene) showed an approximately 30% lower wear rate than the gamma-irradiated and stabilized specimens (crosslinked polyethylene). When tested on the hip simulator, the EtO sterilized specimens exhibited two to three times higher wear rates than the gamma irradiated and stabilized specimens. The ranking of wear resistance obtained with the hip simulator was strikingly different than that obtained with the linear reciprocating wear machine. This study indicates that screening wear machines based on linear motion do not correlate with multi-axial joint simulators and may produce misleading results in the prediction of clinical wear performance of UHMWPE bearing materials.
A Tapered Double-Cantilever-Beam Specimen Designed for Constant-KTesting at Elevated Temperatures
Authors: Beres W , Koul AK , Thamburaj R
Published: February 2009

A compact, constant stress intensity factor, side grooved, tapered double-cantilever-beam (T-DCB) specimen has been designed for measuring elevated temperature creep and fatigue crack growth rates. This specimen is much smaller than the standard DCB specimen generally used for studying corrosion fatigue in airframe materials and it can be easily accommodated in standard furnaces generally used in elevated-temperature fracture mechanics testing. The specimen possesses a constant-K region of 30 mm. This constant-K crack length range was first established analytically through detailed two- and three-dimensional finite-element analyses and the finite-element calculations were further verified experimentally through quantitative fractographic analysis using the striation measurement technique.
Application of Analysis of Variance (ANOVA) Statistical Methods to Breaking Load Corrosion Test
Authors: Golinkin IA , Ruff DD , Kvam EP , McCabe GP , Grandt AF
Published: February 2009

The breaking load test was used for evaluating the effectiveness of a corrosion preventive compound to protect aluminum alloy 2024-T351 from stress corrosion cracking. This test determines the post-exposure fracture stress of smooth tensile coupons exposed to 3.5% NaCl alternate immersion while held at various stress levels. Three groups of specimens were examined: uncoated specimens, specimens coated before environmental exposure, and specimens coated after one day of exposure. Statistical procedures based on analysis of variance methods were used to analyze the data. This statistical methodology shows much promise as a general approach to analysis of breaking load test data.
Experiments Increase Understanding of Chronic Obstructive Lung Disease
Authors: Kayser B
Published: February 2009

The study of chronic obstructive lung disease shows that the discomfort experienced by sufferers of this disease is largely due to their inability to empty the lungs during expiration. After inducing pulmonary hyperinflation in healthy subjects, researchers studied the results in an attempt to develop new breathing techniques and upper-body strengthening exercises suitable for patients. Extensive instrumentation was required to monitor test subject's breathing patterns. A data acquisition and analysis package that allowed researchers to view, plot and analyze data while the experiment was being run was essential in quantifying the results of the experiments. The complete acquisition, analysis and plotting solution was built in a single software environment.
Dynamic Young's Modulus Measurements in Metallic Materials: Results of an Interlaboratory Testing Program
Authors: Wolfenden A , Harmouche MR , Blessing GV , Chen YT , Terranova P , Dayal V , Kinra VK , Lemmens JW , Phillips RR , Smith JS , Mahmoodi P , Wann RJ
Published: February 2009

The results of a round-robin testing study are presented for measurements of dynamic Young's modulus in two nickel-based alloys. The Interlaboratory Testing Program involved six types of apparatus, six different organizations, and specimens from a well-documented source. All the techniques yielded values of dynamic Young's modulus that agreed within 1.6% of each other. For Inconel alloy 600 the dynamic modulus was 213.5 GPa with a standard deviation of 3.6 GPa; for Incoloy alloy 907 the corresponding values were 158.6 and 2.2 GPa, respectively. No significant effect of frequency over the range 780 Hz to 15 MHz was found.
Flexural and Shear Moduli of Full-Section Fiber Reinforced Plastic (FRP) Pultruded Beams
Authors: Bank LC
Published: February 2009

An experimental methodology is presented for the simutaneous determination of the section flexural modulus and the section shear modulus of thin-walled fiber reinforced polyester and vinylester pultruded beams. A pilot test program, involving four different fiber reinforced plastic (FRP) beams, is described and results are discussed. A slenderness ratio is introduced to characterize the shape of the thin-walled beam, and recommended values of this ratio are suggested for design purposes. With available values of the section moduli the designer has the option of using the Timoshenko beam theory instead of the Euler-Bernoulli beam theory.
Experimental Determination of Hydrostatic Compression versus Volume Change Curves for Cellular Solids
Authors: Fortes MA , Fernandes JJ , Serralheiro I , Rosa ME
Published: February 2009

A floatable solid immersed in a liquid can be made to sink if enough pressure is applied to the liquid to increase the density of the solid to the value of the density of the liquid. If a counterweight, W, is attached to the solid, the sinking pressure is reduced. A simple equation gives the volume of the solid as a function of the sinking pressure for each value of W. This is the basis of an experimental method developed to obtain the volume change, Δ V, of a fairly deformable solid, as a function of pressure, p. The method was applied to cork and two polymer foams; (−Δ V/V0) versus p curves were obtained. These curves are compared with stress-strain curves obtained in uniaxial compression.
Cytotoxicity of Incinerator Fly Ash on Alveolar Macrophages
Authors: Liu WK , Wong MH , Tam NFY
Published: February 2009

Fly ash samples were collected from the electrostatic precipitator of a municipal incinerator in Hong Kong. The physical and chemical properties of fly ash particles of a diameter smaller than 10 μm were studied by a scanning electron microscope incorporated with an X-ray energy dispersive microanalyzer, atomic absorption spectrophotometer, and X-ray powder diffractometer. The particles were very heterogeneous in size and shape and had high levels of trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn).

The cytotoxicity of fly ash particles was assessed using an in vitro culture assay of rat alveolar macrophages. It was found that the particles damaged the surface morphology of the cell, decreased the cell viability and phagocytic activity, and increased the release of cytoplasmic (lactate dehydrogenase) and lysosomal (β-glucuronidase) marker enzymes into the culture medium. No hemolytic effect could be measured on the rat red blood cells, indicating that the plasma membrane is not the target site of the incinerator fly ash.
An Experimental Technique for Studying the Dynamic Stability of Slurry Fuels
Authors: Kesavan SK , Chu ML , Reddy NP , Yazdani S
Published: February 2009

In coal slurry transportation, repeated vertical accelerations larger than the gravitational acceleration are encountered. The sedimentation behavior of the slurry fuels under these conditions is an area of concern in fuel transportation. A laboratory-scale technique has been developed that can be used to study the sedimentation behavior of coal slurry fuels under conditions of repeated vertical accelerations. A coal slurry sample contained in a settling column is subjected to repeated vertical movement using a mechanical shaker. The coal concentration profile along the height of the settling column can be used to quantify the sedimentation behavior of the slurry.
A Compression Test for High Strength Ceramics
Authors: Tracy CA
Published: February 2009

A new uniaxial compression test, developed for high strength ceramics, has successfully measured the strength of 94% alumina (Al2O3). Testing was done using a procedure developed specifically for obtaining strengths to 10 GPa on very difficult to machine ceramics. Strain gage analysis and fractographic observations confirmed that a uniaxial compressive stress state existed. Two existing test methods were also employed to measure the compressive strength of the alumina. Results from these tests are compared with the new methodology.
Fatigue Crack Front Shape and Its Effect on Fracture Toughness Measurements
Authors: Towers OL
Published: February 2009

The shapes of fatigue cracks in fracture toughness test specimens have been reviewed for a sample of approximately 680 three-point bend specimens. Up to 17% of this sample would be rejected for plane strain fracture toughness for Mode I loading KIc test procedures because of fatigue crack front shape. The corresponding rejection rate to crack tip opening displacement (CTOD) procedures is 3%. The results of published work for aluminum alloys indicate that relaxation of the KIc testing standards' restrictions on shape would not cause undue errors. This indication, however, appears to conflict with a computer model of curved crack fronts in a compact tension specimen. The suggestion is therefore made that the calculation procedures for fracture toughness determinations should be made more appropriate to the curved crack fronts usually observed, before the limits quoted in the standards are relaxed. To reduce the number of crack length measurements the removal of one limit on crack front shape is suggested. Finally, experimental justification for the change from the limits on crack front shape of British Standard Draft for Development DD19 [1972]) to those of the current CTOD testing standard, British Standard Methods for Crack Opening Displacement (COD) Testing BS 5762 (1979), is presented.
In-Plane Compression: A New Laboratory Forming Technique to Study the Effect of Large Drawing Deformations in Sheets on Their Subsequent Mechanical Behavior
Authors: Charpentier PL , Piehler HR
Published: February 2009

The deformation mode or strain path imposed during sheet forming can have a strong influence on the mechanical behavior of materials, both during and after forming. To study strain path effects, laboratory forming techniques capable of producing deformed samples that are flat, of sufficient size, and relatively free from strain gradients are desirable. A new laboratory forming technique, called in-plane compression, has been developed in this study to produce samples in which the strain state approximates that observed in the flange of a partially drawn cylindrical deep-drawn cup, that is, ϵ2 < 0, ϵ1 and ϵ3 > 0, where ϵ1, ϵ2, and ϵ3 are the principal logarithmic strains. These samples exhibit good strain uniformity and are of adequate size (31.8 by 76.2 mm by sheet thickness) to permit subsequent measurement of the postformed mechanical properties. For a 552-MPa (80-ksi) yield-strength high-strength low-alloy (HSLA) steel, it is shown that the postformed tensile properties after in-plane compression agree well with those observed after cup drawing, thus validating the use of in-plane compression to simulate drawing deformations.
Some Factors Affecting Cement Mortar Strength Results Using ASTM Standard Test Methods C 348 and C 349
Authors: Zoldners NG , Carette GG
Published: February 2009

The purpose of this study was to determine the effect of certain factors on test results when using ASTM Methods C 348 and C 349. For this purpose, four series of 3 mortar mixes each were made, and companion test specimens were molded using both hand tamping and vibrating methods. The results showed that, (1) Compaction of mortar test prisms by hand tamping produced densities which increased from the center towards both ends of the prism by an average of 2.1 percent; whereas this increase for prisms which were compacted by vibration averaged only 0.3 percent: (2) Compressive strengths by modified cube tests at the end locations averaged 5.6 percent higher than those at the middle of broken halves of the prisms compacted by hand tamping, but there was only 0.7 percent difference in strengths for the prisms compacted by vibration (Series IV): (3) The density of prisms compacted by vibration was, on the average, 3 percent less than that of tamped prisms. However, their flexural strength, on the average, was 8.5 percent higher than that of prisms compacted by tamping. (4) In comparison with standard 2-in. (50 mm) cube strengths, the compressive strengths of modified cube tests at the middle of broken halves and at the end of the prism averaged 96.0 and 101.7 percent, respectively, for tamped or 96.2 and 96.8 percent, respectively, for vibrated test specimens.
Capillary Porosity in Hardened Cement Paste
Authors: Auskern A , Horn W
Published: February 2009

The porosity and pore size distributions of cement pastes of water/cement ratios of 0.35 and 0.55 were measured by high pressure (50,000 psi) mercury porosimetry. Measurements were made on pastes hydrated from 8 hours to 90 days. The variation of mercury porosity with maturity was found to correlate well with generally held concepts of the hydration of cement paste.

Differences in the pore size distributions between pastes of different water/cement ratio lie mainly in the region of large pores.
Indirect Measurements of Compliances in Four-Point-Bending Tests
Authors: Fett T , Diegele E
Published: February 2009

Compliance measurements are often necessary in fracture mechanical investigations. In high temperature bending tests the displacements are hardly accessible at the points of load application. An indirect method is proved by finite-element calculations and experimental displacement measurements.
Mechanical Testing of Stainless Steel Bone Staples
Authors: Liberace R , Ladin Z
Published: February 2009

Bending characteristics of stainless steel bone staples were examined to determine their possible inclusion in future standards. These characteristics included a measure of the initial slope of the bending curve as the staples were bent in a four-point bending load apparatus and a factor which accounts for the decrease in staple stiffness due to the bends in the staple. Both factors were measured and showed variations as high as 20% when similar size staples from different manufacturers were compared. Material properties such as hardness and tensile strength were also measured, and the resulting values were within 5% of each other for similar size staples. These results suggest that the staples were made from wire with very similar mechanical properties and that the observed variations are probably due to differences in the manufacturing process.
Comparison of Materials for Staple Pull-Out Tests
Authors: Thomas AMC , Pynsent PB , McCombe PF
Published: February 2009

Maximum pull-out forces of 16 mm bridge width staples of 10, 15, 20, and 25 mm leg length were tested in cadaver femoral metaphyseal bone. Pull-out force was related to leg length, but there was a very wide standard deviation. A plastic composite bone and beech hardwood were tested as substitutes and found to be unsuitable. A balsa wood composite was found to provide more reproducible results and is recommended for staple testing.
New Formulae for Determining Fracture Toughness of a Wide Range of Different Materials with Chevron-Notched Short-Rod and Short-Bar Specimens
Authors: Yin XC , Chen TG
Published: February 2009

New formulae are presented to re-evaluate plain strain fracture toughness of brittle and ductile materials from previous works on chevron-notched specimens. The fracture toughness KIm from the new formulae agree with values of KIC from ASTM specimens. The KIm measurements are successful in tests of tough aluminum when the fracture toughness exceeds 40 MPa · m1 2 and steel 20G with the plasticity factor p approach 1. It is found that the valid specimen size could be smaller than 1.25(KIC/σS)2 for aluminum alloys, and even less than 0.1(KIC/σS) for steel 20G when the KIm formulae are used.
Time-Domain Ultrasonic Measurement of the Thickness of a Sub-Half-Wavelength Elastic Layer
Authors: Zhu C , Kinra VK
Published: February 2009

This work is motivated by the need to measure the thickness of extremely thin adhesive layers in adhesively bonded joints. The classical method for ultrasonic determination of the thickness of a plate is the so-called “time-of-flight” method. One launches a longitudinal wave normally incident upon an immersed specimen and records the successive reflections from the two walls. The temporal separation between two successive reflections corresponds to the spatial distance between the two walls via the elastic wavespeed. This method breaks down when the specimen thickness (h) is less than three wavelengths (3λ). By combining conventional ultrasonics with the theory of Fourier transforms, Kinra and Dayal developed a technique that worked for h < 3λ. However, their technique runs into a convergence problem when h/λ < 0.5. More recently. Kinra and Iyer have explained the reasons for these convergence problems and refined this technique to the point at which it works satisfactorily down to h/λ = 0(10−2).

The objective of this paper is to report a new technique which accomplishes all of the foregoing objectives without the use of Fourier transforms. The entire ultrasonic nondestructive evaluation (NDE) is carried out in the time domain. Whereas the implementation of the previous technique would require an engineer with a college education, the new technique can be confidently used by a trained technician with no more than a high school education. It is envisioned that the use of the new technique will expand by at least an order of magnitude the technology base in which ultrasonics can be used for thickness measurement.
Dynamic Shear Modulus Measurements with Four Independent Techniques in Nickel-Based Alloys
Authors: Blessing GV , Wolfenden A , Kinra VK , Chen YT , Dayal V , Harmouche MR , Terranova P
Published: February 2009

Experimental results are presented, on a round-robin basis, to study the effect of vibrational frequency on the dynamic shear moduli of two metals, Inconel 600 and Incoloy 907. Four separate laboratories, each using a different experimental technique, obtained results over the nominal frequency range of 7 kHz to 10 MHz. A brief discussion and comparison of the four techniques, both resonant and pulse, are included. No significant differences were observed for each alloy's modulus over this frequency range.
Contoured Wood Double Cantilever Beam Specimen for Adhesive Joint Fracture Tests
Authors: River BH , Okkonen EA
Published: February 2009

The strain energy release rate and associated parameters are useful measures of adhesive bond quality. A properly contoured double cantilever beam specimen excels in measuring these properties. However, previous specimen designs presented experimental difficulties resulting in possible bias and poor reproducibility. A new composite specimen is described that overcomes these problems. The specimen is made of oriented strandboard (OSB) and has a concave taper; two contoured beams sandwich a wood laminate having the test bondline at its center. Unlike previous specimen designs, this new specimen allows bonding of the test joint under normal conditions and produces a linear relationship between specimen compliance and crack length. These changes improve the accuracy and reproducibility of the test results with adhesively bonded wood joints. This report describes how the new specimen was developed and how to experimentally determine the compliance and crack-length relationship used to calculate the strain energy release rate of an adhesive joint. Furthermore, the reproducibility of two sets of specimens and the use of the method to analyze differences in actual joint quality are shown and discussed.
Quality Assessment Tests for Nails
Authors: Chiang YJ , Chu MH
Published: February 2009

The quality of nails may be measured by the assessment of their impact bend angle, flexural yield strength, or hardness. Testing for the determination of these criteria as conducted by White, McLain, and Padla [1] is based on three factors carbon content (denoted by SAE number), nominal shank diameter, and hardening. The factorial analysis of their experimental results is presented in this paper Given the nonlinear variation of the flexural yield strength versus the carbon content [1], our analysis is divided into two blocks (1) a low-carbon region, between SAE 1010 and SAE 1022 and (2) a high-carbon region, between SAE 1022 and SAE 1040 The impact of main effects and multiple-factor interactions on each criterion is explored in each block. Results show the SAE class to be a valid indicator of the flexural yield strength in both the low- and highcarbon regions. However, hardening must be taken into consideration as another effective factor when the carbon content is high.
Flow and Stability Limits for Six-Inch-Diameter Marshall Specimens
Authors: Newtson CM , Turner JP , Schmidt RJ
Published: February 2009

Finite element analyses were conducted to determine appropriate specifications for limits on flow and stability of 6-in. (152.4-mm) diameter specimens in the Marshall procedure for mix design of bituminous concrete. Loads and deformations on 6-in.-diameter specimens were determined that result in a state of stress similar to that in 4-in. (101.6-mm) diameter specimens at initiation of yield. From these results, dimensionless scaling factors were determined by which stability and flow specifications for 4-in.-diameter specimens can be multiplied to determine appropriate limits for 6-in.-diameter specimens. These analyses provide a more rational basis for evaluation of stresses and deformations that occur in the Marshall test than has been provided previously. The results yielded scaling factors of 1.50 for flow and 2.25 for stability, which verify the results of experimental results reported in the literature.
Future of Water Treatment
Authors: Puckorius PR
Published: February 2009

The future industrial use of water will continue its current trend toward recycling of poorer quality waters particularly for cooling system makeup and boiler feedwater. Most of our water sources will continue to degrade to higher salinity, higher suspended solids, organics, and phosphates. We will be discharging less waste-water because treatment and recycling will be more economical than the fees for noncompliance. New technology in equipment and chemicals will enable much greater recycling in cooling and boiler water systems, with energy conservation continuing to be fine-tuned.

The next 100 years will also include greatly improved water system monitoring tied to computer-controlled chemical feed, thus reducing manpower requirements but enabling more efficient use of chemicals. Results will provide longer equipment life, less cleaning, more efficiency in heat transfer, more efficient steam production, and greater effluent reduction.
Sensitivity of Water Leak Tests for Latex Condoms
Authors: Herman BA , Carey RF , Rinaldi JE
Published: February 2009

As part of quality assurance testing, latex condoms are often screened for pinholes using water leak tests. This report analyzes the seasitivity of two similar tests, both requiring that a condom be filled with 300 mL of water and then examined visually for leakage. One test, a Food and Drug Administration protocol, specifies that the condom be filled vertically, the open end pinched off, and then rolled horizontally on a towel. The second test, developed by the American Society for Testing and Materials, is the same, except the condom is not rolled, merely placed in a horizontal position and examined. Detectability of a defect is dependent on the pressure developed within the condom, wettability of the condom surface by the water, thickness, and expansion of the condom. Three brands and nine different models were studied to determine the range of values for these variables and the sensitivity of the tests were then calculated. Sensitivity (minimum hole size detectable) varies from approximately 100 μm radius to 3 μm radius. Note that the smallest defect observable is larger than the HIV virus.
Outliers in Interlaboratory Testing
Authors: Mandel J
Published: February 2009

The widespread practice of rejecting outliers on the basis of statistical tests of significance is shown to accomplish nothing in terms of finding the causes for discrepancies. A graphical procedure, based on the h-statistic and the k-statistic, is shown to provide a vivid picture of the biases and the internal precisions of the participating laboratories. It is highly recommended that the analysis of the data be followed by an investigation of causes of outhers and thereby lead to improvements in repeatability and reproducibility.
Introduction of a New Dynamic Fracture Toughness Evaluation System
Authors: Kobayashi T , Yamamoto I , Niinomi M
Published: February 2009

Instrumented Charpy impact test has been widely used as a simple method for semi-empirically evaluating material impact toughness. The authors have developed a new instrumented Charpy impact testing system, which is called CAI (Computer Aided instrumented Charpy Impact testing) system. Using the CAI system, dynamic fracture toughness parameters such as Kd, Jd, Tmat, and various absorbed energies can be obtained from the load-deflection curve of a single precracked specimen for both ductile and brittle materials. It has been already put into practical use in Japan. This paper introduces the details of the toughness evaluation procedures in the CAI system.
The Design of a Control System for a Superimposed Frequency Fatigue Test Machine
Authors: Stoten DP , Smith DJ
Published: February 2009

The conjoint action of high- and low-frequency fatigue on a test specimen has been obtained using a servohydraulic test machine. A control strategy was implemented such that only one servo-actuator was required to obtain both low- and high-frequency components. This paper describes the test rig and the decoupled automatic controller development for it.

Test results show that the decoupled strategy systhesis produces satisfactory separation of the low- and high-frequency modes of the closed-loop response.
Novel Stage for Ultrasonic Measurement of Real Contact Area Between Rough and Flat Parts Under Quasi-Static Load
Authors: Polijaniuk A , Kaczmarek J
Published: February 2009

The paper contains a description of an ultrasonic method and stage for real contact area (RCA) measurement on steel flat parts with technological surface layer. The stage allows measurement of RCA of test surface in contact with a rigid flat counterface. The measurement can be taken during the process of surface deformation as well as for the surfaces already deformed.
Evaluation of Static and Dynamic Contact Stresses in Simulated Granular Particles Using Strain Gages
Authors: Xu Y , Shukla A
Published: February 2009

The application of strain gages for the determination of static and dynamic contact loads in granular perticles is demonstrated. For experimental convenience, the grandar particles are simulated by circular disks fabricated from Homalite-100, a brittle polyester material. Stress field equations in the vicinity of the contact points are carefully evaluated to optimize the relative position of strain gages. The results obtained from strain gages were compared with those obtained using the optical technique of photoelasticity for both static and dynamic problems. Finally, as an example, strain gages are used to study wave propagation in a single chain assembly of disks.
The Vibration-Flex Test Method to Determine the Susceptibility of Plastic Films to Pinhole Formation Due to Flexing
Authors: Varughese JV , Gyeszly SW
Published: February 2009

A test method that uses a vibration table and helical compression springs has been developed to deterinine the susceptibility of plastic films to pinhole formation under conditions of repeated flexing. The setup, results, and limitations of the vibrationflex test are discussed.
Analysis of Marshall Test Behavior with Triaxial Test Determined Material Properties
Authors: Low B-H , Tan S-A , Fwa T-F
Published: February 2009

The Marshall test is one of the most common methods used for mix design and quality control of asphalt concrete mixtures. However, this method is empirical in nature and does not provide fundamental engineering properties. Fundamental engineering properties provide a basis for rational analysis and design of asphalt concrete pavements. The triaxial test method described in this paper allows engineering properties such as internal angle of friction. φ. cohesion, c, and elastic modulus. E. to be determined. The method of specimen preparation and the triaxial test setup are briefly described. A numerical simulation of the Marshall test is performed using a plane-stress finite element analysis with triaxial test determined properties as input parameters. A constitutive plasticity model based on the Drucker-Prager yield condition is used to describe the elasto-plastic behavior of the specimen. Analysis shows that the model very well describes the deformation progression before failure and can predict experimental Marshall stability value very closely. There is some underprediction of the Marshall flow, probably due to the idealization of an elastic-perfectly-plastic stress-strain relationship for asphalt concrete.
An Advanced Control Concept and Algorithm for Long-Term Data Acquisition in High-Temperature Fracture Mechanics Tests
Authors: Liu H , Dogan B
Published: February 2009

An advanced control concept and algorithm are developed for real-time, computer-driven data acquisition and control in long-term high-temperature fracture mechanics tests. The control concept and algorithm provide a comprehensive and reliable solution for problem posed by data acquisition, reduction compression, and control during long-term measurements. A new software developed on the basis of the algorithm enables simultaneous data acquisition and control at multiple parallell-running testing machines in real-time. The data acquired using the software exhibit the statistic characteristics that are reasonable and acceptable for long-term fracture mechanics tests. The algorithm also makes it possible to run other programs parallel with ongoing data acquisition and control processes so that the capacity of the applied computer may be used more effectively. The structure of the software is designed in a user-oriented style so that users can readily apply it along with related measurement instruments and computer systems to perform data acquisition, processing, and control.
Mean Stress Diagrams for Composites Generated Using a Modified Up-and-Down Test Methodology: Part I—Extensive Preliminary Data
Authors: Little RE
Published: February 2009

Constant-stress-amplitude axial-load fatigue tests were conducted to generate mean stress data for notched and unnotched specimens of a thermoplastic composite material with 40% (by weight) randomly oriented continuous-strand glass in a polypropylene matrix. Maximum likelihood point and interval estimates for the median fatigue strengths at 107 cycles were computed for four stress ratios R (−1.0, −0.2, +0.2, and +0.6) based on tests conducted following a modified small sample up-and-down methodology appropriate when extensive preliminary data are available to aid in test planning.
A Mechanical Extensometer for High-Temperature Tensile Testing of Ceramics
Authors: Liu KC , Ding JL
Published: February 2009

Design and development of a simple mechanical strain extensometer for high-temperature tensile testing of ceramic materials are described. The extensometer uses the lever-arm concept to proportionally reproduce the displacements of fiducial gage marks defined on a specimen. Various potential errors in strain measurement associated with the kinematics of this mechanical extensometer are analyzed and estimated. The extensometer exhibits a resolution of 5 microstrain (μɛ) and good long-term stability under moderate changes of ambient temperature. Limited results of simple isothermal creep tests on silicon nitride tensile specimens are presented to demonstrate the effectiveness of the device.
Analysis of Jet Fuel Thermal Oxidation Deposits by Spectral Fluorometric Technique
Authors: Brice JL
Published: February 2009

The Jet Fuel Thermal Oxidation Test (JFTOT) is a widely used ASTM test procedure that evaluates the thermal stability of a fuel. It is evidenced by the fuel's resistance to undergo any chemical changes during increased thermal oxidative stress, until such time that a thermal breakpoint temperature is reached. A characteristic trace of the fuel is then deposited onto an aluminum test coupon and the fuel is rated on a pass/fail books relative to industry standards. Current rating systems approved by the industry for evaluating these tube deposit formations often fail to generate repeatable rating results. The required visual inspection of these deposit areas produces considerable uncertainty among many reviewers (due to a host of uncontrolled variables within the human observer). This paper will focus on the needs of the industry for an improved method of evaluating jet fuel thermal oxidation deposits using laser-induced spectral flourometry (SF). A novel device for reading these tube deposit areas from the cylindrical surface of an aluminum test coupon will be described as well. The overall technique yields an array of objective criteria for the evaluation of heater tube deposit areas and shows great potential for the identification of individual jet fuels on the basis of their fluorescent profiles.
Static Structural Integrity Monitoring System
Authors: Mo YL
Published: February 2009

Using graphical user interface (GUI) and a database management system, the system described here monitors the structural integrity of industrial buildings. This paper examines the nature of GUI design as practiced in the computer industry and its suitability for application of monitoring structural integrity. The GUI design, database management, graphical editing, and implementation of the load monitoring system are presented.
An Assessment of the Piezoelectric Ultrasonic Composite Oscillator Technique (PUCOT) for Measuring the Elastic and Technical Constants of Solids
Authors: Wolfenden A , Harmouche MR
Published: February 2009

An assessment of the methodology of the piezoelectric ultrasonic composite oscillator technique (PUCOT) shows that the present PUCOT equations are invalid for anisotropic materials. The appropriate differential equations governing elastic waves propagating in thin rods are solved for the required relationships between the response resonant frequencies and the elastic constants. Experimental results for silver, aluminum, and copper single crystals, which have anisotropy factors of 3.1, 1.2, and 3.2, respectively, are presented to support the theoretical findings.
Enhancing Thermal Hazard Awareness with Compatibility Charts
Authors: Gay DM , Leggett DJ
Published: February 2009

Compatibility (or Inter-Reactivity) charts provide a rapid and straightforward approach to the plant-wide dissemination of hazards associated with the inadvertent mixing of chemicals. This paper will describe The Dow Chemical Company's approach to the building and use of these charts. Incorporation of compatibility charts in safety and routine process chemistry training and for hazard evaluation will also be described. The benefits of using a personal computer to generate uniform charts will be addressed.
Techniques for the Determination of the Static and Dynamic Internal Friction Coefficients of Ceramic Powder
Authors: Martínez MA , Cortés R , Sánchez-Gálvez V , Navarro C
Published: February 2009

This paper discusses different techniques for the experimental estimation of the static and dynamic internal friction coefficients of fragmented ceramics. These were applied to the powders of two ballistic ceramics, SiC and Al2O3. The relationship between the fragment sire and the internal friction coefficients of the powders was determined. The results obtained with the different techniques are compared.
Formulation and Application Technologies for Microbial Pesticides: Review of Progress and Future Trends
Authors: Cibulsky RJ , Devisetty BN , Melchior GL , Melin BE
Published: February 2009

During the past twenty years, a number of technological advancements have been made in the development of microbial pesticides for use in agricultural and forest insect control programs. The microbial pesticide currently used for the majority of these applications has been Bacillus thuringiensis (Bt) var. kurstaki. This organism has proven itself to be a valuable tool for the control of lepidopterous insects on vegetables, cotton, soybean, and in hardwood and coniferous forests. The expansion of Bt from the original vegetable crop applications to field crops and forest insect control programs has occurred along with significant advances in technology involving the culture, mass production, formulation, and application of this unique microbe. The current interest in Bt and microbial insect control agents has been heightened by the recent development of significant resistance to chemical insecticides in a number of target insect species.

Additional advances in Bt formulation and application are foreseen for the next decade. These advancements should lead so further improvements in efficacy and increased usage of Bt preparations in agriculture and forestry.
Automated Data Acquisition and Load and Strain Measurement Resolution
Authors: Lehman FL
Published: February 2009

Automated data acquisition for compaterized analysis has become commonplace. Typical testing systems now have, in addition to traditional analog or digital indicators for load and strain measurement, data acquisition subsystems that provide load and strain data to a computer for later analysis. Current standards specify procedures for the verification of load and strain accuracy based upon readings from analog or digital indicators. A standard procedure must be developed for the verification of load and strain acquired data. Such a procedure must define a method for determining resolution from characteristics of the acquired data. This paper discusses the issues pertaining to resolution of measurement as it applies to accuracy verification.
Calibration Techniques for Extensometry: Possible Standards of Strain Measurement
Authors: Watson RB
Published: February 2009

The search for an adequate reference strain measuring technique for use in the materials testing laboratory has spanned several decades. Early methods relied on properly calibrated extensometers. Two examples are Tuckerman's Optical Strain Gage and Bergqvist's highly refined inductive and strain gage based extensometers. Length standards were used to calibrate these devices Initially, mechanical displacement mechanisms were used as extensometer checking devices, but with the advent of lasers, the Michelson interferometer has become a dominant displacement measuring tool Advances in stabilizing hardware and electronic detectors have led to the availability of Michelson systems with a resolution better than 5 nm. Microelectronics manufacturing techniques have been used to replicate entire Michelson systems on a silicon chip Advances in detector technology have also led to interferometric linear encoders with resolutions commensurate to classical interferometers. New techniques are being developed that can report strain and do not require initial calibration by displacement measuring instruments Moire interferometry, using a reference grating frequency of 2400 lines mm, has many valuable traits for providing laboratory strain measurements traceable to the National Institute for Standards and Technology (NIST). Experience with strain calibration by more indicates a measurement uncertainty of less than 0.1% corresponding to an accuracy of better than 1 μm m. Bonded metallic electrical resistance strain gages possess essentially limitless resolution, but accuracy must be established. When properly calibrated, bonded strain gages operating within their elastic range could serve as Class A extensometers. This paper reviews some of the more interesting approaches from the past, analyzes some current methods being investigated, and comments on possibilities for the future concerning the difficult task of finding a suitable calibration technique for use with strain measuring devices.
The Use of Robotics to Eliminate Testing Variability in the Evaluation of Polymeric Matrix Composites Subjected to Three-Point Flexure
Authors: Croman RB , Jefferis DW
Published: February 2009

A set of 54 flexural specimens of unidirectional AS-4 graphite reinforced J-2 Polymer, an amorphous thermoplastic polymeric matrix, was tested via a robotic testing setup. Because the testing was robot performed, it is here claimed that the variation of the test results is produced by the variability of the material and not by variation in testing method. An analysis of the test results has been correlated to the various aspects of the failture history observed for these specimens. In addition, an analysis of the scatter in failure strengths has been used to predict the scatter previously observed in flexural fatigue lifetimes.
A New Apparatus for Measuring the Drainage Properties of Porous Asphalt Mixes
Authors: Tan SA , Fwa TF , Chuai CT
Published: February 2009

A new apparatus is designed to measure the permeability of porous asphalt road mixes under laboratory conditions. This apparatus works on the falling head principle, from which the falling head with time through a porous specimen is measured with a pracise pressure transducer at very close time intervals (10 readings/s). Using the falling head data, she specific discharge through the specimen can be computed and the penneability of the material obtained from the velocity versus hydraulic gradient relationship. Tests on unbound specimens made with glass spheres showed excellent agreement with constant head test results. The influence of specimen diameter and thickness in relation to particle size is examined, and recommendation for appropriate specimen size proposed. Tests with three types of common porous asphalt mixes were conducted and it is demonstrated that specification of void content alone is not adequate for describing the drainage property of a porous mix.
A Constitutive Model for Metals at High Strain Rates Accurately Determined by the Tensile Impact Recovery Experimental Technique
Authors: Wang C , Zhou Y , Xia Y
Published: February 2009

Based on the loading-unloading test, the tensile impact recovery experimental technique has been developed to obtain the isothermal stress-strain relations of materials under high strain rates. The thermal softening effect can be decoupled by comparing the isothermal stress-strain relations with the adiabatic stress-strain relations at the same strain rate. In the present paper, recovery experiments of brass have been carried out on a self-designed rotating disk tensile impact apparatus. According to the parabolic strain hardening power-law thermoviscoplastic constitutive model, strain hardening parameter, strain-rate strengthening parameter and thermal softening parameter have been decoupled from experimental results. Furthermore, from these parameters, one can determine the theoretical isothermal curves and adiabatic curves at high strain rates, showing a good match with the experimental results respectively. This shows that the teasile impact recovery experimental technique is effective and reliable, and is an important means for the study of thermomechanical coupling. The experimental results also reveal that brass is a typical thermoviscoplastic material.
Characterization of Styrene-Butadiene-Styrene Polymer Modified Bitumens—Comparison of Conventional Methods and Dynamic Mechanical Analyses
Authors: Lu X , Isacsson U
Published: February 2009

Rheological properties of styrene-butadiene-styrene polymer (SBS) modified bitumens were studied using conventional test methods (penetration, softening point, kinematic viscosity and Fraass breaking point) and dynamic mechanical analysis (DMA). The study indicated that SBS modification improved the viscoelastic properties of bitumens, which can be demonstrated using DMA but not conventional methods. Significantly improved properties of binders included increased dynamic mechanical moduli and decreased phase angle at high temperatures, as well as reduced complex modulus and increased phase angle at low temperatures. SBS modification also caused reductions in glass transition temperature, Fraass breaking point, and temperature susceptibility. The degree of improvement was observed to be influenced by bitumen source/grade and polymer content/structure. Comparison showed that certain relationships exist between parameters obtained using conventional methods and DMA, such as between penetration and complex modulus, kinematic viscosity and complex viscosity, and Fraass breaking point and glass transition temperature. However, the main conclusion of the study is that conventional test parameters such as penetration and softening point are not suitable for characterization of rheological properties of SBS modified bitumens.
Measurement of the Fracture Energy of Interfaces in Composites Through Sandwich-Type Chevron-Notched Specimens
Authors: Shaw LL
Published: February 2009

A sandwich-type chevron-notched specimen with a phase angle of loading near zero has been proposed to measure the fracture energy of interfaces arising mainly from chemical bonding. With the specimen configuration of this kind, the advantages from both sandwich test specimens and chevron-notched specimens can be combined to provide an easy and accurate test for the measurement of the interfacial fracture energy. The validity of the specimen has been analyzed in terms of the mechanics of sandwich-type specimens and chevron-notched specimens, and demonstrated using the Al2O3/Nb bimaterial system. The results show that for a phase angle of loading around −7° the Al2O3/Nb interface has a fracture energy of 9.3 ± 0.2 J/m2 that changes to 16.8 ± 1.1 J/m2 when Nb is preoxidized before the formation of the Al2O3/Nb interface.
A Test Method to Determine the Relative Humidity Dependence of the Air Permeability of Woven Textile Fabrics
Authors: Gibson PW , Elsaiid AE , Kendrick CE , Rivin D , Charmchi M
Published: February 2009

This paper describes a test method used to determine the relative humidity dependence of the air permeability of hygroscopic woven textile fabrics. Changes in fabric structure as hygroscopic fibers swell at high humidities can have a large influence on the measured air permeability of materials such as cotton, wool, silk, and nylon fabrics. The method is sensitive enough to show sorption hysteresis effects in the relative humidity versus air permeability curve. The instrumentation also permits dynamic measurements during a step change in relative humidity. Typical results are shown for seven fabrics, covering a range of fiber hygroscopic properties and air permeabilities.