bluuebunny/crossref_metadata_2025 huggingface dataset:
Low and High Cycle Fatigue Interaction in 316L Stainless Steel
Authors: Wong YK , Hu XZ , Norton MP
Published: February 2009

The interaction between initial low cycle fatigue (LCF) and high cycle fatigue (HCF) in 316L stainless steel is reported. Specimens were introduced to varying degrees of LCF and subsequently subjected to HCF until failure. LCF involves bulk plasticity where stress levels are usually above the yield strength of the material. On the other hand, HCF is predominantly elastic, and stress levels are below the yield strength of the material. Fatigue was carried out under strain control where two strain amplitudes in the LCF range with a common HCF strain amplitude were investigated. Results show that fatigue life decreased when specimens were introduced to increasing numbers of initial LCF. A linear life trend is observed for high numbers of LCF introduction, which deviates from linearity when lower numbers of LCF were introduced. It is therefore concluded that initial LCF causes substantial irreversible damage, subsequently reducing fatigue life in the HCF regime.
A Critical Appraisal of Fracture Toughness Measurements on AA6061 and an Al2O3-Particle Reinforced AA6061 Alloy for Various Heat Treatments
Authors: van Gorp AC , Mussert KM , Janssen M , Bakker A , van der Zwaag S
Published: February 2009

A disadvantage of metal matrix composites (MMCs) is their assumed brittleness, which results in a low KIc. A possible way to make aluminum MMCs tougher is to heat treat them. In this investigation the influence of three different heat treatments on the KIc of AA6061 and AA6061 with 20 vol% Al2O3 is investigated. Special attention is paid to the set of requirements needed to obtain a valid KIc, as in some studies these are given little attention. In MMC material, the specimen geometry is governed by the delivered shape, which increases the risk of obtaining KQ instead of KIc values. It proves to be possible to obtain valid KIc data for the MMC using the standard disk-shaped compact tension geometry.

The KIc of the MMC is around 21 MPa √m and the influence of the heat treatments on the KIc seems to be very small. The reduction in KIc by the addition of 20 vol% Al2O3 particles to AA6061 is moderate, in view of the KIc of the matrix material, which on average is 27 MPa √m.
A Finite Element Investigation into the Effect of a Skew Insert in a Double-Cantilever Beam Specimen on Calculating Mode I Delamination Fracture Energy of Unidirectional Composites
Authors: Javidrad F , Mashadi MM
Published: February 2009

In the present paper, the effect of a skew insert in a double-cantilever beam specimen in evaluating Mode I delamination fracture energy (GIc) of unidirectional laminated composites is investigated numerically. A delamination growth analysis incorporating the finite element method is utilized to calculate variation of load-displacement-delamination length for a prescribed GIc as delamination propagates along the specimen. In order to evaluate the values of GIc as a function of delamination length, the calculated data were treated as experimental data and processed using two ASTM standard test data reduction methods. These are the modified beam theory and the compliance calibration methods.

It is found that the skew front moves progressively to form a thumb-nail curved front during a few millimeters of growth. Part of this growth occurs within the specimen, not visible from the specimen edges where the delamination lengths were recorded during a test. It also is found that the difference between delamination lengths measured at each side of the specimen can have a significant effect on the calculated GIc. To eliminate this error in an actual test, it is suggested that the larger delamination length be used for data processing.
Direct Measurement of Displacement in Instrumented Charpy Impact Testing for Structural Integrity Assessment
Authors: Tronskar JP , Mannan MA , Lai MO
Published: February 2009

The present research aims to develop a method for the direct measurement of load-line displacement during instrumented Charpy impact tests. The method involves direct measurement of the load-line displacement using a laser interferometer in addition to the load-line displacement derived from the load signal by double integration according to standard procedures. The ISO striker edge is instrumented with a piezoelectric sensor and the system is calibrated in situ in the impact tester as recommended by ISO 14556:2000 Steel Charpy V-notch Pendulum Impact Test—Instrumented Test Method, using a 0.5% accuracy reference load cell and a hydraulic jack system.

Introductory tests were conducted using fatigue precracked and V-notched specimens in the temperature range + 23 to −80°C on a conventional ship grade steel NVE36 for application in floating production, storage, and off-loading (FPSO) vessels. The results were promising and good correlation was obtained with results from conventional instrumented impact testing where the load-line displacement was calculated by double integration of the force versus time plot.
The Effects of Residual Stress, Loading, and Crack Geometry on SEPB Fracture Toughness Test Results
Authors: Grendahl S , Bert R , Cho K , Bar-On I
Published: February 2009

Use of the single-edge precracked beam (SEPB) specimen with the “bridge indentation” method is one of the new ASTM standard test methods for the determination of fracture toughness of advanced ceramics. In support of this effort, the effects of several test parameters on the fracture toughness values were established. The effects of the residual stress due to the indent, the alignment in three- and four-point bending, and the crack front straightness on the fracture toughness values were determined using aluminum nitride specimens. The results show that indent loads should be kept below 100 N (10 kg), and the crack plane angle should be less than 5° in order to prevent artificially high fracture toughness values. Crack front straightness requirements can be less stringent than generally accepted.
Sensitivity Analysis of the Small Specimen Bulge Test by the Finite Element and the Taguchi Methods
Authors: Li W , Hellen TK , Brookfield DJ , Mottershead JE , Whelan M
Published: February 2009

Small punch and bulge tests have been applied to determine material properties from small specimens in the power generation industry for a number of years. This paper applies the finite element (FE) and the Taguchi methods to carry out the sensitivity analysis of the small specimen bulge test to variations of seven parameters. The FE model takes into account elastic/plastic material properties, large strain, and contact behavior with friction. The sensitivity of the punch force to the variation of these parameters has been studied. The relationship between the maximum punch force and the punch displacement and the yield stress of the tested sample has been identified using the orthogonal polynomial regression technique.
A Finite Element Analysis of the Stress Intensity Resulting from Single-Edge Precracked Beam Loading Conditions
Authors: Turner D , Kibble KA
Published: February 2009

The single-edge precracked-beam (SEPB) fracture toughness method has been investigated using finite element methods to analyze the stress intensity (KI) resulting from variations in bridge span, punch length, and virtual crack length. A two-dimensional half-plane, semi-infinite model was used to approximate the stress intensity from a fit of the nodal displacements of a crack face under SEPB loading conditions. The finite element method models the crack in situ, using six-node triangular elements specified around a singular point that simulates the crack tip.

The analysis reveals that for increasing virtual crack length (a), the stress intensity increases to a maximum where ΔKI/Δa = 0. With further increasing virtual crack length, the stress intensity decreases. The inflection point ai, KIi differs for varying span and fixed punch length, and for varying punch lengths with fixed span.

The resulting stress intensities per new ton force loading are presented in tabular and graphical form. The presented series of graphs can be used to explore variations in precracking parameters. This finite element analysis provides useful data for those developing or adopting the SEPB fracture toughness measurement technique.
Calibration of Thin Heat Flux Sensors for Building Applications Using ASTM C 1130
Authors: Zarr RR , Martinez-Fuentes V , Filliben JJ , Dougherty BP
Published: February 2009

Calibration measurements of thin heat flux sensors for building applications are presented. The findings support the continued development of precision and bias statements for ASTM Practice C 1130. Measurements have been conducted using a 1016 mm diameter guarded hot plate apparatus (Test Method C 177) from 10°C to 50°C and for a heat flux range of ± 13 W/m2. The option of using a 610 mm heat flow meter apparatus (Test Method C 518) to calibrate the heat flux sensors is also explored. Experimental designs are presented to compare test methods, evaluate which parameters affect the sensor output, and determine the functional relationship between the sensor output and applied heat flux. The study investigates two sizes of sensors fabricated by one manufacturer. Sensor equivalency, grouped by size, is evaluated to determine whether a calibration based on a subset of sensors will suffice or if extensive individual calibrations are needed.
Geometry of Solidification. I: Shrinkage Criterion Using Results from Finite Element Analysis
Authors: Windelberg D
Published: February 2009

The solidification of molten base material often produces porous or cracked products. Following the investigations of Hansen and Sahm, we try to optimize the product in relation to fewer pores, cracks, and tensions: therefore, we observe the process of solidification of the base material. For the modeling of solidification we use the results of a commercial finite-element analysis program that solves the heat transfer equation. We define a criterion that describes the “goodness” of a casting and discuss the results of the calculation with respect to pores, cracks, and tensions of the product. A “vector of quality” is introduced to describe the results as a certification of the product and to compare castings.
Heavy Metal Retention Behavior of Clayey Soils
Authors: Pandian NS , Sridharan A , Rajasekhar C
Published: February 2009

Effective waste management requires the protection of groundwater resources against potential contamination from the leachates generated by the land disposed wastes. In general, waste disposal facilities are lined with impermeable barriers to protect against the migration of leachates into the natural water bodies. Clayey soils, due to their easy availability and economic viability, are normally preferred as liner materials. In this regard, extensive laboratory studies have been conducted on clayed soils to understand their permeability behavior as affected by the permeation of contaminant cationic solutions. It is also known that the clayey soils retain the heavy metal ions due to their surface characteristics. However, relatively little information is available on the retention characteristics of clayey soils. Hence, in this study, an attempt has been made to study the retention characteristics of clayey soils upon permeation of inorganic cationic solutions. The results indicate that the major portion of the retention of metal ions by clayed soils is through ion exchange.
Notes on Direct Current Potential Drop Calibration for Crack Growth in Compact Tension Specimens
Authors: Tong J
Published: February 2009

In using the direct current potential drop method for crack growth measurement, a suitable reference location on the test piece of a compact tension (CT) specimen seems difficult to find and yet is highly desirable for high-temperature long-term testing. This short report presents a possible solution that seems promising based on our preliminary test results. Vanations in the potential and current lead placement were also evaluated for some typical lead configurations in CT specimens.
Superpave Shear Tester as a Simple Standardized Measure to Evaluate Aggregate-Asphalt Mixture Performance
Authors: Shenoy A , Romero P
Published: February 2009

The present work provides a standardized method by which various mixtures can be compared and their expected performance can be assessed in a uniform manner using the Superpave shear tester. Based on the present findings, it is evident that complete mixture evaluation can be done through the frequency sweep at constant height (FSCH) data from the Superpave shear tester (SST), without the need to generate the repeated shear at constant height (RSCH) data. This would reduce the experimental time without compromising the information obtained.

FSCH and RSCH data at different temperatures are generated on the SST for a number of aggregate-asphalt mixture combinations. The shear moduli versus frequency data from the FSCH at different temperatures are unified to form a single curve for each mixture so that a specification parameter Ts (°C) can be determined.

Each unified curve is fitted with a constitutive equation from which model parameters are evaluated. The slope B1 in the low frequency region of the unified curve, when normalized with the term (T/Ts), results in a parameter that relates to the permanent strain after 5000 cycles in RSCH at any temperature T. There is a good possibility that the slope B2 in the high frequency region of the unified curve may relate to distresses in the intermediate temperature range, such as fatigue. If this is proven true through future research, then the Superpave shear tester could earn the distinction of being a “simple performance tester.”
Determination of the Energy Necessary for Creating Fatigue Cracks by Measurement of Microhardness
Authors: Benguediab M , Mazari M , Ranganathan N
Published: February 2009

The growth of cracks is related to the existence of a plastic zone at the crack tip, the formation and growth of which are accompanied by an energy dissipation. The estimation of this energy is generally made by global measures. In our study, we have used microhardness measurements at the crack tip for estimating energy. The results obtained are more accurate near the crack tip than those estimated by other methods.
An Apparatus for Evaluating Adhesion Between Soils and Solid Surfaces
Authors: Subba Rao KS , Allam MM , Robinson RG
Published: February 2009

An apparatus in the direct shear mode has been developed to conduct soil-soil and soil-solid material interface tests in the undrained condition. Evaluation of the apparatus showed that all the requirements for simulating the undrained condition of shear are satisfied. The interface test results show that the adhesion factor α increases with the surface roughness of the solid material. In the case of the normally consolidated state, α is practically independent of the undrained shear strength of the clay for a given surface. For the overconsolidated state, α depends on the undrained shear strength and the overconsolidation ratio for smooth surfaces but for rough surfaces, α is independent of both undrained shear strength and overconsolidation ratio.
Evaluation of Sharp Indentation Testing of Thin Films and Ribbons on Hard Substrates
Authors: Larsson PL , Peterson IRM
Published: February 2009

A numerical investigation of sharp indentation of thin films and ribbons has been conducted using the finite element method. For a wide variety of material behavior, the critical ratio of indentation depth to thin film thickness is determined for the case of indentation of thin films or ribbons perfectly clamped on hard substrates. The critical ratio is defined as the ratio at which the indentation response can no longer be considered closely acceptable to the corresponding response at indentation of bulk materials. The indentation parameters investigated are hardness (average contact pressure), the size of the contact area between indenter and material, and the initial unloading slope of the indentation load-indentation depth curve. The implications of the results for material characterization of thin films and ribbons by indentation are discussed in some detail.
Precision and Equivalence of Automatic and Manual Flash Point Apparatus
Authors: Montemayor RG , Collier MA , Lazarczyk GG
Published: February 2009

The flash point of a liquid material is used to classify whether the material is flammable or combustible. Historically, flash point determination has been done using manual flash point apparatus. However, the advent of automatic flash point apparatus, especially in the petroleum and related industries, brought about improved testing efficiency such that manual flash point determination is becoming the less preferred way of determining flash point. Three ASTM standard test methods, namely, D 56 “Flash Point by Tag Closed Cup Tester,” D 92 “Flash and Fire Points by Cleveland Open Cup,” and D 93 “Flash Point by Pensky-Martens Closed Cup Testers” are the most common test methods used in the various specifications and regulatory requirements for determining the flash point of materials. Three interlaboratory studies were conducted in 1991 to determine new precision values for the ASTM D 56, D 92, and D 93 flash point test methods, and to determine if the flash points obtained by the automatic apparatus are statistically equivalent to the flash points obtained by the manual apparatus in each of these three standard test methods. The pooled repeatability at a 95% confidence level for the D 56 flash point was found to be 1.1°C (manual) and 1.2°C (automatic) for flash points below 60°C; and 1.4°C (manual) and 1.6°C (automatic) for flash points at or above 60°C. The pooled reproducibility for D 56 at a 95% confidence level was found to be 4.1°C (manual) and 4.3°C (automatic) for flash points below 60°C; and 5.8°C (manual) and 5.1°C (automatic) for flash points at or above 60°C. For D 92, a repeatability at a 95% confidence level of 4°C (manual) and 8°C (automatic); and a reproducibility at a 95% confidence level of 13°C (manual) and 18°C (automatic), were obtained. The precision for D 93 was shown to be dependent on the flash point value, with a repeatability at a 95% confidence level of 0.032 X °C (manual) and 0.035 X °C (automatic), and a reproducibility at a 95% confidence level of 0.073 X °C (manual) and 0.078 X °C (automatic). Standard statistical evaluation tests were performed on the data for the three test methods. Essentially, no statistically significant differences were found between automatic and manual D 56, automatic and manual D 92, and automatic and manual D 93 flash point results. Thus, the interlaboratory studies of the three flash point test methods indicated that automatic flash point results are equivalent to manual flash point results.
Precision and Relative Bias of Automatic and Manual Refractometers Using ASTM D 1218 at 20°C
Authors: Montemayor RG
Published: February 2009

The refractive index at a given temperature is an important specification parameter for a large number of petroleum products as well as various paraffinic, olefinic, and aromatic hydrocarbon solvents. It is an easy and quick test method to assure the quality and identity of a specific material. Historically, refractive index and refractive dispersion have been measured using manual refractometers. The advent of digital automatic refractometers has made the measurement of refractive index much easier. An interlaboratory study was conducted in 1996 to determine the precision of automatic refractometers and to compare the results with manual instruments. The study involved eight different samples, ten laboratories that used automatic instruments, and six laboratories that used manual instruments, using ASTM D 1218, Test Method for Refractive Index and Refractive Dispersion of Hydrocarbon Liquids, at 20°C. The repeatability of both automatic and manual refractometers was determined to be 0.0002. The reproducibility of both automatic and manual refractometers was determined to be 0.0005. The study showed that there was no statistically significant difference between results obtained with automatic and manual refractometers using ASTM D 1218 at 20°C at a 95% confidence level.
Precision and Relative Bias of Automatic and Manual D 1078 Distillation
Authors: Montemayor RG
Published: February 2009

ASTM D 1078 Distillation Range of Volatile Organic Liquids is included in the specifications for a number of organic materials used in the paint and related coatings industry, such as hydrocarbon solvents, olefinic solvents, alcohols, ketones, glycols, and esters. Historically, only manual D 1078 distillation has been used. In the last decade, however, the use of automatic distillation has become increasingly prevalent. There are fewer and fewer laboratories that use the manual method. In order to be able to incorporate automatic instruments into the present D 1078, it was necessary to establish the comparative precision and relative bias of the automatic D 1078 procedure to the manual D 1078 procedure. An interlaboratory study was conducted in the summer of 2000 involving six samples of varying distillation ranges, ten laboratories that used automatic instruments, and five laboratories that used manual instruments. The precisions for the initial boiling point, 50% boiling point, and the dry point were found to be dependent on the boiling point temperature. The precision for the distillation range was found to be dependent on the distillation range. Automatic D 1078 distillation results were found to be statistically equivalent to manual D 1078 distillation results. The average relative bias for the six samples included in the study was 0.5°C. ASTM D 1078 has been revised to reflect the new precision value and relative bias of the automatic D 1078 and the manual D 1078 distillation.
An Extrapolation Method for Estimating Crack Growth Rate Confidence Intervals from Small Fatigue Crack Data
Authors: Carlson RL , Halliday MD
Published: February 2009

Small fatigue crack growth data for the aluminum alloy 6061-T651 are analyzed to obtain confidence intervals for the mean crack growth rate as a function of crack length. Results of an extrapolation procedure are presented to illustrate how variations in crack size and elapsed load cycles in the early stages of crack growth may be examined.
On Bounding a Near-Zero Probability When Zero Occurrences Appear in a Sample
Authors: Proctor CH , Luko SN
Published: February 2009

In attribute sampling, it is sometimes the case that the investigator will report a “zero response” in the sample. This means that where a specific attribute has been defined, no occurrences having the attribute are observed in the sample. When this event occurs, it may be tempting to report a result of “zero defects” or simply that the attribute was not observed within the sample. It may even be concluded that defects are not to be expected from the process or lot since none were observed in the sample. This paper shows that this reasoning is false and shows how to bound the probability of future occurrence of a defined attribute, under various conditions of sampling, when zero occurrences are exhibited in a sample. Several common scenarios of sampling are considered, including sampling from a process, sampling finite or isolated lots, and sampling from a continuum. In addition, some common sampling problems such as errors of misclassification and autocorrelation are considered.
The Relation Between an Extreme Proportion and a Less Extreme Proportion, in the Context of the Comparability of Tests
Authors: Hutchinson TP
Published: February 2009

Data are sometimes encountered consisting of the proportions of items falling into each of three ordered categories in a number of different circumstances. The examples in this paper concern properties of particulate material, such as the proportion of particles considered to be fractured. Methods are proposed for relating the proportion satisfying some stringent criterion (e.g., two or more fractured faces) to the proportion satisfying some less stringent criterion (e.g., one or more fractured faces). Emphasis is on methods whose success or otherwise can be seen graphically.
Fatigue Testing and Evaluation of Asphalt Binders Using the Dynamic Shear Rheometer
Authors: Shenoy A
Published: February 2009

The dynamic shear rheometer (DSR) is being used currently by the asphalt pavement community for determination of the viscoelastic properties of asphalts following the recommendations of the Strategic Highway Research Program. The Superpave specification parameter |G*| sinδ was identified as the term to be used in rating the asphalt binders for their fatigue resistance. However, in subsequent research work, it was found that this parameter did not relate well with the accumulation of fatigue damage of mixtures measured through a beam fatigue test under strain-controlled conditions. This led researchers to seek other methods of characterizing fatigue resistance behavior of asphalt binders. The suggested new test was a binder fatigue test using the time sweep on the DSR. The number of cycles to fatigue failure Nf was chosen as the criterion for rating the fatigue resistance of the binder.

The present work reevaluates the binder fatigue test in order to establish the proper window for choosing the correct experimental conditions for getting meaningful results that would describe true fatigue behavior and not experimental artifacts. The fatigue tests are conducted at different temperatures of Te (°C) for various binders in order to ensure equistiffness conditions (identical initial complex modulus |G*i| values) at the start of the test. It is shown that the cycles to fatigue failure is directly a function of the initial loss modulus G″i, or in other words, the Superpave specification parameter |G*i| sinδi, and is also related to the loss modulus obtained through a strain sweep G″s or |G*s| sinδs at the temperature Te (°C). It is recommended that a specification temperature TIS = Te (G″s/|G*s|) = Te sinδs be used for ranking the binders in terms of their expected fatigue behavior.
Use of Surfactants in Condom Water Leak Testing
Authors: Kerr LN , Mailhot SA , Boivin WS , Hamilton SL , O'Malley LG , Boyd SM , Pierdominici VJB , Bushar HF
Published: February 2009

This paper identifies an appropriate surfactant solution to improve the defect detection rate of the ISO/FDA water leak test method for condoms. A surfactant solution and concentration are identified to optimize leakage testing of condoms, considering factors of safety, cost, reproducibility, and hole detection. Defect detection rates are compared using the ISO/FDA method with and without the surfactant solution.

Micro-90® concentrated cleaning solution is selected as a suitable surfactant for water leak testing of condoms due to reliable formulation, low sudsing, low cost, and no disposal or toxicity problems. A concentration of 0.1% by volume optimizes the effectiveness of the solution while minimizing solution concentration.

Detection rates of standardized defects are quantified for four condom types tested with and without surfactant solution. Use of surfactant solution in the ISO/FDA method increases the detection rates of all defect types and sizes in all the condom types tested. This increase is statistically significant for 10 (out of 48 possible) combinations of condom type, hole diameter, and hole location.
Visualization of Localization in Grain Skeletons with Particle Image Velocimetry
Authors: Nübel K , Weitbrecht V
Published: February 2009

An optical method called Particle Image Velocimetry is well-suited to observe strain localization in plane strain conditions of granular bodies. A detailed description of different deformation states can be obtained. The experimental data can be used for the verification and physical interpretation of numerical models.
Retrieval and Interpretation of Crash-Related Data from Nonresponsive Electronic Control Units in Land Vehicle Systems
Authors: Rosenbluth W , Adams HA
Published: February 2009

This paper discusses methods and procedures for recovering valuable vehicle crash parameter data from EEPROM/flash memory in damaged devices in the subject crash vehicle. The objective of these methods and procedures is the revival of seemingly dead or inoperative post-crash on-vehicle electronics control units (ECUs) to recover potentially valuable at-crash vehicle parameters from data that may be retrieved from EEPROM within these ECUs. In many instances, such data can strongly assist an accident investigator in his/her analysis of a crash scenario.

The first section consists of methods whereby an investigator can properly clean and restore a previously nonresponsive ECU/PCB/component to functional diagnostic operation by applying successive methodical and tested procedures. If such cleaning procedures fail, the process of component substitution is illustrated.

The second section shows an example of a complex interpretation process for a hypothetical EEPROM data example in an ABS ECU. While hypothetical, this example is very real-world in concept and content, and shows that information important to a crash investigation can be derived from EEPROM data in many types of on-vehicle ECUs.

Lastly, a discussion of Forensic Neutrality with Respect to Electronic Data Interrogations is presented with an example of the special methods required to achieve this with current interrogation tools.
Enhancement of Asphalt Pavement Evaluation Using Monte Carlo Simulation and Accelerated Pavement Testing
Authors: Li S , Li Y , Metcalf JB
Published: February 2009

Pavement engineers often are required to evaluate quickly new pavement structures, new paving materials, or pavement performance. In the past decades, pavement engineers have employed prediction models or tests to fulfill these tasks. Recently, great effort has been made to utilize accelerated pavement testing (APT) to evaluate pavements in situ. Because APT requires building test sections and sophisticated loading facilities, the individual test section is very short and the number of test sections is usually small. Consequently, the test results may not take into account variability in pavement materials, traffic estimation, and surrounding conditions. This paper investigates use of Monte Carlo simulation in conjunction with APT to evaluate asphalt pavement structure and performance. It is shown that the capability of APT for pavement evaluation has been enhanced. The proposed pavement evaluation approach allows for considering variability in pavement properties and traffic estimation, and can generate realistic results.
Fatigue Mechanism of Ion-Nitrided Low Carbon Steel
Authors: Makabe C , Makishi T , Kaneshiro H
Published: February 2009

The fatigue strength and the fracture mechanisms of ion-nitrided steel were investigated using three types of specimens—annealed specimens, nitrided specimens, and specimens from which the surface layer was removed (surface-removed specimens). The latter specimens' surface layers were removed after nitriding, reducing their radius by 0.1 mm. The fatigue limit of the nitrided specimens was higher than that of the annealed specimens, but was almost the same as that of the surface-removed specimens. This is related to the hardness distribution of the specimens. In the case of the nitrided specimen, the maximum hardness was recorded at the surface and decreased gradually toward the center of the specimen. The estimated strength deduced from the hardness of that specimen is higher than the measured fatigue limit within a depth of 0.1 mm from the surface. At internal depths of more than 0.1 mm from the surface, the estimated strength is expected to be lower than the fatigue limit. Accordingly, the fatigue limit and strength of the nitrided specimens are determined by the internal properties of the materials, and thus the fatigue limit and strength of the nitrided specimens are not decreased even if the surface layer is removed. In the case of the nitrided specimens, the cracks were difficult to observe from the surface because the crack initiations occurred internally. Since removing the surface layers facilitates observing the cracks on the surface, the initiation mechanism of internal cracking can be evaluated by observing surface crack initiation. In the case of the surface-removed specimens, many cracks initiated and propagated along the needle-shaped precipitates of Fe4N and finally these cracks coalesced with each other. From the observation of the fracture surfaces, a similar mechanism is assumed to be operating internally in the nitrided specimens.
The Effect of Simulated Clinical Use on Vinyl and Latex Exam Glove Durability
Authors: Kerr LN , Boivin WS , Chaput MP , Hamilton SL , Mailhot SA , O'Malley LG , Teixeira JC
Published: February 2009

A simulated clinical-use study was conducted in order to verify the failure rates found in the literature and to identify the failure modes and typical locations of defects in vinyl and latex exam gloves. A simulated clinical-use protocol consisted of approximately 12 min of manipulating various medical devices. This simulated clinical use created significantly more defects in vinyl gloves (35%) than in latex gloves (9%). The user's dominant hand was significantly associated with defect rate in vinyl gloves (60%) but not in latex gloves (56%). The majority of the defects (74%) in the vinyl gloves were located in the thumb and index finger. The defects in the latex gloves were distributed evenly among the palm/back of hand, thumb, index finger, and cuff. Typical defects consisted of holes, slits, tears, and abrasions.
The Fundamental Threshold Level—a New Parameter for Predicting Cavitation Erosion Resistance
Authors: Soyama H , Kumano H
Published: February 2009

In order to predict and avoid cavitation erosion, it is necessary to know the resistance of materials to cavitation impacts. It is proposed that only cavitation impacts with energy larger than a certain threshold level affect the cavitation erosion of materials. Weak cavitation impacts have small impact energy, which cannot produce elastic or plastic deformation on materials. Cavitation erosion does not take place in this situation. On the other hand, strong cavitation impacts have large impact energy, which generates plastic deformation and/or causes damage with mass loss. It is proposed that only cavitation impacts that are larger than a certain threshold level affect the cavitation erosion of materials. In this paper, the existence of such a threshold level is revealed experimentally. The fundamental threshold level of the material is a new parameter suitable for the prediction of cavitation erosion rate. The erosion rates for several materials were determined by using a cavitating jet erosion test, which forms a new ASTM standard, ASTM G 134. The cavitation impacts induced by the cavitating jet were measured by means of a specially made PVDF transducer and the energy of the cavitation impacts were then calculated. The fundamental threshold levels for several materials were obtained from the relationship between the erosion rate and the energy of the cavitation impacts. A method to predict cavitation erosion quantitatively from the fundamental threshold level of the material and the measurement of cavitation impacts is proposed.
Optimal Quality Characteristic Evaluation for Asphalt Mixing Plants
Authors: Divinsky M , Nesichi S , Livneh M
Published: February 2009

The development of a quality system for asphalt mixing plants based on original statistical development is the subject of the current investigation. Quantitative evaluation of the quality characteristic under study and distinguishing the quality level for the plant production process have been analyzed. Results for the diagnostic parameter and quality characteristic evaluations (statistical estimations) have been analyzed and compared, employing process capability indices and the control chart method. Quality evaluation of the asphalt mixture produced based on the quality mark (QM) characteristic presented during a previous analysis and corresponding statistical analysis for diagnostic parameters of the presented results and their practical application are discussed. Additional development of the QM characteristic prediction model has been fulfilled and applied in practice. Results presenting the quality mark characteristic behavior with respect to an elaborated general index have been compared with analogous behavior generated using conventional indices for quality mark evaluation. The model presented for quality mark evaluation regarding asphalt mixing plant production and its practical application provides a significant level of efficiency, but requires further development.
Improvement of Sulfur Detection Limits in Petroleum Products Using ASTM D 4045
Authors: Tawara K , Kawabata Y , Uno Y
Published: February 2009

To prevent the adsorption impediment of H2S in the trace sulfur analyzer approved by ASTM D 4045, a specially prepared pure ceramic tube has been advanced to be the only usable reactor for hydrogenolysis procedure. However, a conventional ceramic tube becomes usable by inhibiting the H2S adsorption on the basic impurities by a substitute adsorption of CO2 that can be introduced continuously with H2 in the ceramic reactor. Applying the OxyHydro procedure to reduce the carbon deposit in the analysis of kerosene, a large overestimation error occurred in the determination of a single ppb of sulfur even using the specially prepared pure ceramic tube. The overestimation error was completely eliminated by the continuous introduction of CO2 with H2, even using conventional ceramic reactors. By following procedures to suppress noise from the system, the original limit of detection of 25 ppb sulfur for the analyzer was improved to 0.3 ppb.
Texture Measurement in Zr-2.5%Nb Pressure Tubes for Pressurized Heavy Water Reactors
Authors: Kapoor K , Ramana Rao SV , Sanyal T , Kashyap BP
Published: February 2009

Preferred orientation or crystallographic texture of Zr-2.5%Nb pressure tubes for a pressurized heavy water reactor (PHWR) affects all the critical in-reactor properties. The preferred orientation has to be measured to standardize the process route for getting the desired in-reactor properties. The quantitative determination involves determination of the complete pole figure and calculation of Kearns parameters from the pole figure data. Independently, neither the X-ray reflection nor the X-ray transmission technique can provide the full pole figure data. The literature reports only partial pole figures. Quantification of texture based on partial pole figures may lead to errors in estimation. For a complete pole figure determination, it is required to merge the data from both the reflection and the transmission techniques. This requires a special test setup that can combine the pole figure data obtained from the two techniques. In this paper, a methodology for determination of the complete pole figure with quantitative texture parameters for Zr-2.5%Nb pressure tubes is reported.
Compression Index of Clays and Silts
Authors: Robinson RG , Allam MM
Published: February 2009

The consolidation settlement of a structure founded on a normally consolidated soil can be calcuated from the knowledge of the compression index Cc. The value of Cc is usually obtained from the laboratory oedometer test on the assumption that the void ratio (e)-logarithm of pressure (log σ′v) plot is linear. While the literature reveals that in the case of highly plastic clays the plots are concave upwards with their Cc (computed between successive load increments) decreasing with an increase in σ′v, little is known regarding soils that are less plastic, in particular, silty soils. This paper reports the e-log σ′v plots of clays and silits. It was found that the e-log σ′v curves of the silts are not linear but are convex upwards. This results in an increase in Cc with an increase in σ′v. Convex curves are to be regarded as a normal feature in such soils and can be explained from consideration of the mechanical and physicochemical factors that govern the compressibility of clays. These factors establish that Cc increases with σ′v for those soils whose compressibility behavior is governed by mechanical factors, in contrast to soils like very plastic clays whose compressibility behavior is governed by physicochemical factors. In the latter, Cc decreases with an increase in the consolidation pressure.
Ruggedness Experiments for a Calibrated Hot Box Measuring Fenestration Systems Thermal Transmittance
Authors: Yuan S , Murch L , Goss WP
Published: February 2009

For a specific test method, ruggedness experiments are used to determine experimental conditions that significantly influence the measurement results and to determine how closely these conditions must be controlled to reduce their influence. In this paper, the results of ruggedness experiments using hot box test methods (ASTM C 1199, C 1363, and ISO 12567-1) that are used for the thermal transmittance measurement of fenestration systems are presented. A general procedure of ruggedness evaluations was conducted on the University of Massachusetts Research Calibrated Hot Box. Using ASTM E 1169, a Plackett-Burman (P-B) design with eight experiments was used to investigate the effects of the seven most important experimental conditions. Two experimental conditions, the weather side and metering side fan speeds, were found to have the most significant effects on fenestration systems thermal transmittance measurement results.
The Wave-in-a-Tube Method for Estimation of Mechanical Properties of Viscoelastic Materials Using Ultrasound
Authors: Lippert SA , Rang EM , Grimm MJ
Published: February 2009

The wave-in-a-tube method allows for the estimation of material properties of gel-like, viscoelastic materials utilizing only a pair of matched ultrasonic pressure transducers. To employ this technique, a sample tube must be manufactured that (1) has an inside diameter that fits snugly around the element of the transducers being utilized, (2) is as long as the specimen size will allow given the diameter required, and (3) is made of a low-density, solid material. After construction of the container, the sample to be measured is placed in the tube with a pressure transducer fitted into each end with large air pockets eliminated. An ultrasonic pulse is sent through the sample, and the resulting waveform is analyzed per the Reynolds wave-in-a-bar method, yielding the magnitude of the complex moduli.
Automatic Classification of Faience Tiles by Artificial Vision
Authors: Bouhlel MS , Elloumi M
Published: February 2009

The detection and identification of defects in fairence tiles during manufacture is necessary for an objective evaluation of quality, and for rapidity of processing. To this end, we are working on the automatic classification of surface defects observed on faience tiles.

The range of production is large and tile imprints are diversified. This leads to a complexity in the choice of the classification method and in the parameters to adopt.

After a subdivision of tiles into several types according to imprint, we propose in this paper, for each type, the methodology and the processing realized in order to classify tiles as 1st, 2nd, or 3rd quality.
Shear Testing of Polymeric Foams
Authors: Benderly D , Zafran J , Putter S
Published: February 2009

A standard method for the determination of the shear strength of a polymeric foam is a lap shear geometry. The accuracy and validity of this test was evaluated by means of finite-element modeling. Model results show that the shear stress is not constant over the length of the sample, with shear peaks at the ends, so that the average shear stress in the sample can be quite different than the maximum shear stress experienced. Normal stresses are also present at the sample ends giving rise to a combined stress field. Experimental results for a polymeric foam bonded to steel edge plates show that the measured shear strength can vary significantly with the sample geometry (length). Maintaining a minimum length/thickness ratio, as specified in the ASTM C 273 standard, does not necessarily result in a sample with the most uniform shear field, and therefore the most accurate measure of the true shear strength.
Temperature Effect on Strain Measurement by Using Weldable Electrical Resistance Strain Gages
Authors: Gomes PTV , Maia NS , Mansur TR , Palma ES
Published: February 2009

Thermal output from two different strain gage types was analyzed over a temperature range from 20–500°C. The influence of applied loads was also examined. The strain gages were attached to the specimens in three different configurations. Thermal output was efficiently compensated for using a quarter-bridge configuration. Relative large errors were found using half-bridge configurations. The obtained thermal output values, with and without application of load, are discussed.
Influence of Crystallographic Texture on X-ray Residual Stress Measurement for Ti-3wt% Al-2 Vwt% Tube Material
Authors: Kapoor K , Lahiri D , Ramana Rao SV , Sanyal T , Kashyap BP
Published: February 2009

Some inaccuracies are possible during the near-surface residual stress measurement of textured material by X-ray diffraction using the standard multiexposure technique. Diffraction intensities depend on factors like inclination of the sample, the rotation of the beam, and the position of detectors. Low intensity due to texture can result in increased percentage error observed stress values. Anisotropy of elastic constants in textured materials can further increase the errors in measured stress. In the present study, the effect of texture on residual stress has been studied for seamless Ti-3wt%Al-2Vwt% tubes, in pilgered and annealed conditions, by superimposing the residual stress measurements on the pole figure obtained by texture measurement. A general approach has been developed for accurate determination of the stress tensor in textured material. This consists of the selection of inclinations giving rise to high intensity peak, the selection of rotation angles symmetric to the pole figure to get similar intensity from both the detectors (where this is not possible one detector with low intensity is shut off), and the calculation of the bulk X-ray elastic constants using the single crystal elastic data and texture. Cold worked Ti-3wt%Al-2Vwt% tubes had the highest stress along the rolling direction and that is compressive in nature. The principal residual stresses in the pilgered tubes were along the rolling and transverse directions, and annealing leads to reduction and reorientation of the stresses.