bluuebunny/crossref_metadata_2025 huggingface dataset:
Short-Term High-Temperature Properties of Reinforced Metal Matrix Composites
Authors: Boland PL , DiGiovanni PR , Franceschi L
Published: February 2009

While the Department of Defense initiated Metal Matrix Composite Information Analysis Center (MMCIAC) has been charged with providing centralized information dealing with metal matrix composites (MMCs), test procedures for obtaining primary MMC properties have evolved from ASTM standards. These standards in turn have evolved from polymeric matrix composite (PMC) test procedures and have not yet been established as appropriate for MMC applications. Methods for obtaining short-term high-temperature tensile, flexural, and pin bearing data for reinforced MMC are presented. In addition, coupon design and fabrication, instrumentation, measurement techniques, and some lessons learned are discussed.

Rapid heating, typical of tactical missile aerodynamic heating, can be suitably simulated using infrared quartz lamps. In fact, this type of furnace facilitates longer term baseline testing since temperatures can be reached more quickly, and test fixtures and equipment can be easily cooled. For short-term high-temperature strain measurements, extensometers were utilized. A computerized, digital data acquisition and control system is necessary to maximize data retrieval and minimize test errors during rapidly changing test conditions. Results show that while tensile strength of MMCs subjected to rapid heating greatly exceed those strengths obtained for long-term heating, flexure and pin bearing strength exhibit only moderate increases. Furthermore, differences are observed for specimens fabricated from thin versus thick panels.
Estimation of Reservoir Submerging Losses Using CIR Aerial Photographs: Example of the Ertan Hydropower Station on the Yalong River in Southwest China
Authors: Lin H
Published: February 2009

A geotechnical project, which used remotely sensed and other spatial data to estimate reservoir submergence losses, was carried out in 1982 at the Ertan hydropower station on the Yalong River in Sichuan province, southwest China. To meet the needs for use of data from spaceborne remote sensing to estimate the losses, color-infrared (CIR) aerial photographs were used as the first step in a series of experiments.

An orthophotomap and a land-cover and land-use map of the submerged region have been completed using 1:45 000 and 1:24 000-scale CIR aerial photographs taken in the winter and spring of 1981. After some typical on-site sampling in the region to be submerged, as well as synthetic analysis on the aerial photographs, a three-level classification system has been developed, with 25 categories of potentially submerged objects classified by use of the maps. Each level of the classification system is decided by the needs of the project design for investigating submergence losses, the resolution of the aerial photographs, and the minimum size of the mapping unit. The length or area of each category on the land-cover and land-use map (1:20 000-scale) is measured using a manual tracking digitizer.

The root-mean-square (rms) accuracy standard was adopted to check the accuracy of the estimate. The accuracy includes the classification and position accuracy of the land-cover and land-use map, and the measuring accuracy of the polygons on the maps. Among the 25 classification categories, the difference between the statistical acreage of cultivated land determined from the estimation method using CIR aerial photographs and from the conventional method of on-site investigation by surveyors was only 3.1%. This project has provided not only the data needed for the design of the hydropower station, but also a data base for use in future experiments using Landsat data.
Application of Spatial Statistics to Analyzing Multiple Remote Sensing Data Sets
Authors: Glass CE , Carr JR , Yang H-M , Myers DE
Published: February 2009

The purpose of this paper is to present results from preliminary research using image spatial statistics to improve the resolution of low-resolution digital images. Improvement is needed whenever images from different sensors, and often when images from different spectral bands within the same sensor, are collected for geotechnical interpretation.

The experimental procedure involves degrading one of two digital images in adjacent spectral bands to simulate a low-resolution image. New samples within the sparse, low-resolution image are subsequently estimated using the spatial characteristics displayed in a variogram function and an estimation process known as co-kriging or co-estimation. The resulting high-resolution estimation image is compared with the original undegraded image as a check on estimation accuracy. Reconstruction accuracy, as judged by mean square error (MSE), improved from MSE = 826 for sample replication to 56 for co-kriging.

For cases where geotechnical decisions rely on accurate knowledge of image amplitudes, this research suggests that co-kriging provides an accurate and flexible estimation technique. Moreover, co-kriging appears to be a promising technique for future automated image interpretation and feature extraction algorithms.
Optical Fourier Analysis of Surface Features of Interest in Geotechnical Engineering: Image Subtraction and Correlation
Authors: Scheibengraber KJ , Pincus HJ
Published: February 2009

Description and comparison of surface features of geotechnical interest are facilitated by the application of optical diffraction analysis (ODA). “Before-and-after” pairs of photographs and series of photographs can be compared by image subtraction (IS), in which one image is subtracted from another similar image to produce a difference image. Optical correlation, in particular joint-transform correlation (JTC), can be used to compare the spatial information in pairs of photographs by a quantitative method yielding a correlation coefficient with values between 0 and 1. Comparisons of series of photographs can be accomplished by JTC by working with pairs of photographs in the series; the series may represent a sequence in time for the same area or a strip or mosaic in space of adjoining areas. Results are presented for IS applied to Landsat imagery of an area in Montana and for JTC applied to an area of the Union of Soviet Socialist Republics. IS is also applied to the optical transforms of an area in California photographed in visible light and in the infrared range.
The Effects of SO2 Scrubber Chemistry on Corrosion of Structural Materials
Authors: Mansfeld F , Jeanjaquet SL
Published: February 2009

The effects of 13 trace elements on the corrosion behavior of Ferralium 255, Hastelloy G3, stainless steel (SS) Type 317L, Monit and Ti Grade 2 immersed in an aerated baseline solution containing chlorides and sulfates at pH 1 or 4 in the presence of sulfur dioxide (SO2) have been studied using electrochemical techniques. In a first series of experiments, a Plackett-Burman test matrix was used to determine which of the trace elements have a significant accelerating or inhibiting effect. Polarization resistance measurements were carried out for electrodes that were totally immersed for the entire six-day test period and for electrodes that were exposed above the solution level, except for 1 h/day, when they were immersed in the test solution. A computerized system was used to perform simultaneous measurements for all five alloys and both types of electrodes using up to ten test electrodes. The results of the electrochemical measurements were confirmed by a correlation analysis using results from a solution analysis and visual observation of the number and dimensions of pits after the test. The concentration dependence of corrosion rates for the five alloys has been studied for those species for which a significant effect was observed in the first test series. For Ferralium 255, Hastelloy G3, SS 317L, and Monit, an accelerating effect of Cu and Fe was observed when a certain concentration threshold was exceeded. For Ti, 1000 ppm fluoride additions produced etching of the surface at pH 1. A comparison with the results of the first test series shows that addition of Al at comparable concentrations can prevent this corrosion damage by complexing the fluoride ions. The effects of single ions added to a modified baseline solution at pH 1 that contained all other trace elements at a median level were further studied by recording potentiodynamic polarization curves after exposure times of 1, 3, and 6 days. For SS 317L, polarization curves are obtained in the baseline solution that are typical for an alloy susceptible to pitting and crevice corrosion. In the presence of 1000 ppm Cu or 2000 ppm Fe, this corrosion damage is increased and the polarization curves are those of highly corroded surfaces. For Ferralium 255, Hastelloy G3, and Monit, which are more corrosion resistant, the anodic polarization curves did not show an active/passive transition, but dissolution at a more or less constant rate. For Ti, the anodic polarization curves showed passive behavior with very low corrosion rates. The susceptibility to localized corrosion was studied further in the same solutions using a multiple crevice device. For SS 317L, severe crevice corrosion was observed in the baseline solution with additions of 1000 ppm Cu or Fe additions exceeding 300 ppm. For the other alloys except Ti, severe damage also occurred for additions of 2000 ppm Fe, but not for 1000 ppm Cu.
Review of Corrosion Studies of Metal Containers Using Synthetic Media
Authors: Murphy TP , Pape GA
Published: February 2009

Corrosion phenomena in metal containers differ from those encountered in, for example, pipeline or bridge construction, in that they can be apparent at very low corrosion rates. Thus, contamination of the contents of the package can occur with relatively low metal uptakes, rendering them unsuitable for use. Dissolution of tin or iron from tinplate and of aluminium from body or end stock are examples of this contamination. Sulphide stains may be unsightly, but are not harmful. Perforation of the container may allow the product to escape, leading to secondary corrosion or contamination, and associated losses; or to the ingress of contaminants, leading to flavor changes or microbial spoilage. In practice, the incidence of problems is very low.

Corrosion testing frequently uses the actual products to be packed; this is the ultimate test. Synthetic systems have been used to simulate complex natural food in particular, but also to clarify the behavior of formulated products. Test methods involve electrochemical studies, coupon testing, and test packing. The behavior of coatings for cans may also be studied in this way. Performance is assessed by considering metal pick-up and incidence of swelling or perforation. Controlled-environment chambers are used in accelerated testing.

Characterization of materials also involves using synthetic media in laboratory testing, e.g., measurement of tin oxide levels in tinplate. The properties of containers and components may be checked using synthetic or, occasionally, natural materials.

While such procedures are helpful in clarifying corrosion processes and studying components or materials, they have limitations. Ideally, the test procedure should correspond to the products to be packed under anticipated conditions of use. Nevertheless, the use of synthetic systems contributes to the optimization of the final container/product combination.
Synthetic Environments for the Testing of Metallic Biomaterials
Authors: Kuhn AT , Neufeld P , Rae T
Published: February 2009

Synthetic environments used for testing biomaterials are considered. In terms of the environment they seek to simulate, these can be subdivided into saliva substitutes and body fluid substitutes. In respect of the former, it is seen that most formulations used in the past cannot even be taken into solution. In both cases, evidence is presented to suggest that use of electrochemical corrosion test methods or in-vivo use of the same methods gives results that are in error because of simultaneous anodic oxidation of organic species, such as simple redox-type amino acids. The correlation between in-vivo and in-vitro corrosion rates is examined. Agreement is far from satisfactory in many cases.
Laboratory Evaluation of Materials for Resistance to Anaerobic Corrosion by Sulfate-Reducing Bacteria: Philosophy and Practical Design
Authors: Stott JFD , Skerry BS , King RA
Published: February 2009

Reliable laboratory test methods for the evaluation of the performance of materials against anaerobic corrosion by sulfate-reducing bacteria are not readily apparent in the literature. Traditionally, such testing has been carried out in small scale “batch cultures” using filled and stoppered vessels or small cells contained in anaerobic jars. The problem with such tests is that they give much lower rates of corrosion than those frequently experienced in the field. This is almost inevitable, as the total quantity of hydrogen sulfide produced is small compared with the surface area of the test coupons, and quickly becomes denuded. From our knowledge of the microbiology and electrochemistry of anaerobic corrosion by sulfate-reducing bacteria, any realistic test must meet certain conditions. The duration must be long enough to allow the stable crystallographic forms of metal sulfide to form. These tend to be nonprotective and cathodic to the metal. The vessel should be sufficiently large to present a realistic volume of test medium to exposed specimens. It should contain a medium that supports the growth of sulfate-reducing bacteria, but excludes organic constituents, which act as inhibitors. It should operate in a semicontinuous culture mode to maintain the organisms in an active state of growth and sulfide production. It should be maintained at a temperature which is compatible with the active growth of the sulfate-reducing bacteria. Air should be effectively excluded. Large anaerobic culture vessels (20-L capacity) have been constructed containing both aqueous and soil environments. These have been used in a number of tests involving various environments. Electrochemical monitoring by linear polarization, electrical resistance, and advanced electrochemical techniques has been incorporated. Results of a 250-day test involving cast iron pipe sections are outlined. The test regime described provides a reliable method for the evaluation of the likely long term anaerobic corrosion behavior of any selected materials and associated corrosion protection methods.
Comparison and Control of Microbial Spoilage of Metal-Working Fluids and Associated Corrosion
Authors: Hill EC , Hill GL , Robbins DA
Published: February 2009

The microbial environment in the metal-working fluid in a machine tool is complex, as the dissolved oxygen content, Eh, and temperature differ at different locations in the system. Thus different species of microorganisms flourish or decline at different points in the fluid depending on their individual needs and preferences. Experiments using simple shake flasks or stagnant flasks in the laboratory can produce misleading results. A recirculation apparatus is described that allows both aerobic and anaerobic microbial growth to occur. It can be monitored and manipulated (for example by reinoculation or the addition of biocides) over a long period. Metal swarf is added to the apparatus and its corrosion can be rated visually. The corrosiveness of the fluid can also be determined at intervals using the standard metal chip test.
Alloy Ranking for Corrosion Resistance Laboratory Tests Versus Field Exposures
Authors: Silence WL , Corey SM , Kolts J
Published: February 2009

This paper reviews the relative ranking of the corrosion resistance of stainless steels and nickel-base alloys. Laboratory rankings for pitting resistance were determined by measuring critical pitting temperatures in chloride-containing solutions with ferric ion additions. The rankings were compared to field test data obtained from locations in coal-fired power generating flue gas desulfurization systems and in various applications in the pulp and paper industry. Excellent correlation was found. Laboratory test results for measuring uniform corrosion resistance do not correlate well with uniform corrosion rates from field racks retrieved from a wide variety of industrial applications.
Synthetic Solutions and Environment Sensitive Fracture
Authors: Parkins RN
Published: February 2009

The stress corrosion cracking of alloys is markedly sensitive to the environment to which they are exposed, so that an alloy developed to have low susceptibility to such failure in a particular environment will not necessarily show such behavior in a different environment, as illustrated by a number of examples. It is also possible for results from tests using standard environments to lead to the exclusion of the use of materials that may behave satisfactorily in service. While it is obvious that tests should be conducted, whenever possible, in environments relevant to particular service conditions, these are not necessarily known when alloy development programs are being undertaken in the laboratory, hence the need for standardized or synthetic solutions. Evidence for the cracking domains for ferritic steels and α-brasses suggests that stress corrosion cracking in a range of environments occurs at potentials and pH's where the lower oxide of the relevant metal can form. This suggests that laboratory tests should involve more than a single standardized environment, and that variation from test to test of potential and pH, guided by the potential pH diagram, may provide a more reliable guide to stress corrosion cracking propensities than that obtained from tests in a single solution.
Intergranular Corrosion of Austenitic Stainless Steels—An Electrochemical, Potentiokinetic Test Method
Authors: Johns DR
Published: February 2009

An anodic polarization test in a perchloric acid-sodium chloride electrolyte has been developed to determine the intergranular corrosion susceptibility of three austenitic stainless steels, American Iron and Steel Institute (AISI) 302, 304, and 316. A region of secondary activity is present in the polarization curves, and the magnitude and potential of the maximum of this secondary activity is related to susceptibility to intergranular corrosion. The initial work involved polarization testing of the main surface of strip and plate material in the solution-treated condition and after heat treatment at 948 K (675°C) for up to 7 days. The correlation between the penetration rate determined by ASTM C 262 and the electrochemical activity is excellent for some materials but poor for others. In the latter, it was clear that end and edge grain attack were dominant in the nitric acid test. However, if the electrochemical activity of all three orthogonal faces of the materials is measured, and a weighted sum determined to reflect the relative areas of each face exposed to nitric acid, then a consistently good correlation with penetration rate is obtained. For material heat treated to provide a range of penetration rates (0.08–14 mm/year) as measured by ASTM C 262, a relationship of mm/year = A (activity)0 5 is found. For low penetration rates (<0.5 mm/year), the power index becomes approximately 0.25. This indicates that the nitric acid test is less able to differentiate between highly resistant materials that still exhibit measurably different electro-chemical activities.
Ammonia Test for Stress Corrosion Resistance of Copper Alloys
Authors: Mattsson E , Holm R , Hassel L
Published: February 2009

Within the ISO Committee TC 26/SC 2, Wrought Copper and Copper Alloys, a Working Group, WG4, has been set up to propose an ammonia test to evaluate the stress corrosion resistance of copper alloy products. To create a basis for such a proposal, the Swedish-Corrosion Institute has initiated a test program, which has been carried out by Metallverken in Sweden. The proposal is based on earlier experience with ammonia tests at Metallverken, including a method originating from F. Aebi and used in Switzerland, Great Britain, and the Federal Republic of Germany. The proposed test procedure involves a 24-h exposure of the test material at room temperature to an ammoniacal atmosphere in equilibrium with an ammonium chloride solution. The vapor pressure of ammonia in equilibrium with the solution depends on the pH value. So, by changing the pH value, the severity of the test can be regulated. For comparison, a selection of materials has been subjected to the proposed test, to other accelerated tests based on ammoniacal corrodants, to the mercurous nitrate test, and to a four-year field test in the urban atmosphere of Stockholm. The results have shown that the proposed method has advantages over other accelerated SCC tests hitherto used for production and acceptance control. The test has been described in ISO standard 6957.
A Synthetic Environment to Simulate the Pitting Corrosion of Copper in Potable Waters
Authors: Goodman PD , Lucey VF , Maselkowski CR
Published: February 2009

The BNF rapid test to assess the ability of water to support the pitting corrosion of copper is described. The test cell provides an environment that simulates conditions that, in service, lead to the pitting of copper. The mode of operation is explained in terms of copper corrosion mechanisms elucidated by investigations carried out at BNF. The development of a synthetic water capable of supporting the pitting corrosion of copper is also described.
Synthetic Versus Natural Marine Environments for Corrosion Testing
Authors: Money KL , Kain RM
Published: February 2009

Comparison of synthetic and natural marine environments is the subject of this paper. The synthetic environments discussed include salt spray or fog, acetic acid salt spray and copper accelerated acetic acid salt spray. Results from corrosion tests conducted in these synthetic or simulated environments are compared to corrosion test results in natural seawater and the marine atmosphere. Laboratory and/or synthetic solutions can and often do rank or predict the relative performance or behavior of a given material, but when their results are compared to the behavior of materials in the natural environment, the investigator must use all of the available data before characterizing performance.
Laboratory Solutions for Studying Corrosion of Aluminum Alloys in Seawater
Authors: Dexter SC
Published: February 2009

The difficulties in obtaining reproducible results for the corrosion of aluminum alloys in saline waters, both in the laboratory and in the field are well known. The various factors contributing to variability in aluminum corrosion data in saline waters are briefly reviewed. This information is then used to evaluate NaCl solutions, enhanced NaCl solutions, synthetic seawaters, and stored seawater as substitutes for natural seawater in studying the corrosion of aluminum in the laboratory. The effects of such factors as dissolved oxygen concentration, pH, temperature, organic content, salinity, and stability of the solution are discussed. While no laboratory solution can replace natural seawater for long-term corrosion testing, an artificial solution composed of sodium chloride, sodium bicarbonate, and magnesium, with controlled oxygen, pH, temperature, and hydrodynamics is suitable for many laboratory purposes. This solution is simple, more stable than either natural or artificial seawater, and closely reproduces the short-term behavior of aluminum alloys in natural seawater.
Particle Containing Formation Water for the Study of Erosion Corrosion
Authors: Kohley T , Heitz E
Published: February 2009

Mass loss rates of a 13% chromium steel have been determined in particle-containing formation water using a loop with a constricted pipe as a test section. Erosion corrosion rates increase approximately with the square of the flow rate and linearly with the sand content. Under CO2-corrosion conditions, changes of the particle parameters (size, concentration) are much more significant than medium parameters (chloride content, temperature).
Pitting of AISI 410 Stainless Steel in CO2-Saturated Synthetic Seawater and Condensate
Authors: McIntyre DR
Published: February 2009

Specimens of American Iron and Steel Institute (AISI) Type 410 stainless steel were exposed to aerated and deaerated solutions of artificial seawater and distilled water, with and without quaternary amine additions, with a CO2 atmosphere. Pitting rates were determined from autoclave exposures, and electrochemical parameters were obtained from potentiodynamic polarization curves.

The studies showed that in deaerated solutions, the amine additions had a mild inhibiting effect on liquid phase pitting in both seawater and distilled water. The amine additions increased the rate of attack in aerated solutions of distilled water. Correlation between electrochemical test methods, laboratory autoclave tests, and field experience is good.
Simulating the Pitting Corrosion of Steel Reinforcement in Concrete
Authors: Sykes JM , Balkwill PH
Published: February 2009

The pitting behavior of steel in solid gels made from alkaline solutions containing chloride ions is shown to be markedly different from the behavior that occurs in the solutions themselves. After an induction period during which composition changes take place at the metalgel interface, pitting can start even at bulk chloride levels at which pitting would not occur in solution. Addition of calcium hydroxide to the gel delays the onset of pitting. Portland cement mortar is a less aggressive environment then the alkaline gels, probably because of the formation of a portlandite layer on the steel surface.
A Cumulative Damage Model for Continuous Fiber Composite Laminates with Matrix Cracking and Interply Delaminations
Authors: Allen DH , Groves SE , Harris CE
Published: February 2009

Experimental evidence has shown that significant stiffness loss occurs in graphite/epoxy laminates when matrix cracking and interply delaminations exist. Therefore, a cumulative damage model for predicting stiffness loss in graphite/epoxy laminates is proposed herein by applying a thermomechanical constitutive theory for elastic composites with distributed damage. The model proceeds from a continuum mechanics and thermodynamics approach wherein the distributed damage is characterized by a set of second-order tensor-valued internal state variables. The internal state variables represent locally averaged measures of matrix cracking and interply delaminations. The model formulation provides a set of damage dependent laminated plate equations. These are developed by modifying the classical Kirchhoff plate theory. The effect of the matrix cracking enters the formulation through alteration in the individual lamina constitution. The effect of interply delamination enters the formulation through modifications of the Kirchhoff displacements. The corresponding internal state variables are defined utilizing the kinematics of the interply delaminated region and the divergence theorem. These internal state variables depend on the components of the displacements created by the delamination.
Two-Dimensional Delamination Growth in Composite Laminates Under Compression Loading
Authors: Flanagan G
Published: February 2009

A closed-form approximate solution for the total strain energy release rate (G) of an elliptically shaped delamination has been developed from thin-film assumptions that treat the delamination as a clamped plate subject to enforced boundary displacements. Approximate equations are derived which couple the large deflection membrane stresses to the out-of-plane deflections. The model restricts the boundary to remain elliptical as the delamination grows. By applying the simple failure criterion that rapid growth of the delamination (which occurs when G reaches a critical value) precipitates the final failure of the laminate, the predicted failure stresses can be correlated with post-impact strength data available in the literature. The Mode I critical G is required for a good correlation, although the model calculates the total G averaged around the perimeter. For impact damage, data on delamination depth are rarely available. However, it was found that by assuming a delamination interface that results in the lowest failure strain, correlation with test data was obtained.
An Experimental Study of a Curved Composite Panel with a Cutout
Authors: Palazotto AN
Published: February 2009

This paper is an attempt to compare a set of experimental measurements on a panel with a symmetrically positioned cutout to values determined through a nonlinear finite element program. The comparison shows the sensitivity of the panel to a varying boundary condition produced by the restraints associated with the experimental structure. The finite element program used is STAGS C-1.
The Development of a Satisfactory, Simple, Shear Fatigue Test for Unidirectional E-Glass Epoxy
Authors: Butler RJ , Barnard PM , Curtis PT
Published: February 2009

An experimental evaluation of the ASTM D 4255 two-rail shear test has been carried out for the fatigue of unidirectional E-glass/913 epoxy. Results from the standard configuration were unsatisfactory with scatter on fatigue life of three orders of magnitude. A close examination of specimens revealed the presence of longitudinal cracks from the specimen free edge caused by the transverse loading component from rail bending. Specimens with such cracks had long lives while specimens without had short lives. The coupon configuration was thus modified with the inclusion of small slots at the location of the longitudinal cracks. This modification greatly decreased scatter of both static strength and fatigue life. Finite-element work showed a consistent shear field in the gage area of the slotted coupon. Experimental work showed a slightly lower value of stiffness from the modified coupon. An effective gage length for the slotted coupon was deduced. A useful S-N curve for unidirectional glass/epoxy in shear has been produced from a simple modification to an existing static shear test method. Its applicability to other materials and layups has been commented upon.
Height-Tapered Double Cantilever Beam Specimen for Study of Rate Effects on Fracture Toughness of Composites
Authors: Yaniv G , Daniel IM
Published: February 2009

A height-tapered double cantilever beam specimen was introduced for the study of loading rate effects on Mode I delamination fracture toughness of graphite/epoxy composite. The material investigated was AS4/3501-6 graphite/epoxy. The height contour of the specimen was designed to provide a slightly decreasing compliance with increasing crack length in order to produce a stable and smooth crack propagation at high rates of loading. Furthermore, the specimen geometry selected allowed the attainment of much higher crack propagation velocities than was possible with uniform or width-tapered double cantilever beam specimens. The specimens were machined from 24-ply and 48-ply unidirectional plates. A 5.08-cm-long (2-in.) initial crack was machined at the narrow end of the specimen. The specimens were loaded in an Instron electrohydraulic machine at constant crosshead (opening deflection) rates ranging from 7.5 × 10−3 mm/s (1.8 × 10−2 in./min) to 460 mm/s (1.07 × 103 in./min) corresponding to crack extension rates of up to 26 m/s (61 500 in./min). This represents a 500-fold increase in crack velocity over that studied in previous work. Crack extension was monitored by means of a conductive-paint circuit applied along the path of the propagating crack. Continuous records were obtained of the load, deflection, and crack extension for determination of the strain energy release rate. The latter was calculated by the beam analysis method extended to include the effects of transverse shear and kinetic energy. It was found that the strain energy release rate increase with crack velocity up to a value of approximately 1 m/s (2360 in./min); thereafter, it decreases with increasing crack velocity. The maximum value of the strain energy release rate was approximately 46% higher than the quasi-static value.
Analytical and Experimental Investigation of the Notched Strength of Thick Laminates with Surface Notches
Authors: Harris CE , Morris DH , Nottorf EW
Published: February 2009

Experimental and analytical investigations of the fracture of a [0/± 45/90]10s graphite/epoxy laminate with part-through semi-elliptic surface notches have been conducted. Experimental values of notched strength were determined for a variety of notch aspect ratios and notch depths. Analytical predictions of laminate failure were obtained from three different models. One model was based on fracture mechanics concepts while the other two models were based on strength-of-materials concepts with a linear and quadratic strain distribution through the laminate thickness at the notch. The kinematic strain assumptions were in part based on results of a moiré interferometry investigation of the strain field at the notch.

The three models were equally successful in predicting the fracture of laminates with deep notches. The experimental results of laminates with shallow notches indicated more notch sensitivity (that is, greater strength reduction) than did the analytical models.
Analysis of Delamination Growth from Matrix Cracks in Laminates Subjected to Bending Loads
Authors: Murri GB , Guynn EG
Published: February 2009

Delamination is the most commonly observed damage mode in laminated composite materials. A major source of delamination damage is from low-velocity impact. In thin composite laminates under point loads, matrix cracks develop first in the plies, and delaminations then grow from these cracks at the ply interfaces. The purpose of this study was to quantify the combined effects of bending and transverse shear loads on delamination initiation from matrix cracks in composite laminates. Graphite-epoxy laminates with 90-deg plies on the outside were tested and analyzed to provide a two-dimensional simulation of the back-surface damage observed during low-velocity impact. Three plate-bending problems were considered: four-point bending, three-point bending, and an end-clamped center-loaded plate. Under bending, a matrix crack will form on the tension side of the laminate, through the outer 90-deg plies and parallel to the fibers. Delaminations will then grow in the interface between the cracked 90-deg ply and the next adjacent ply. Laminate plate theory was used to derive simple equations relating the total strain energy release rate G, associated with the delamination growth from a 90-deg ply crack, to the applied bending load and laminate stiffness properties. Three different lay-ups, [904/0/±45]s, [904/03]s, and [903/0/±45]s, were tested and results compared. Test results verified that in all cases the delamination formed at the interface between the cracked 90-deg ply and the next adjacent ply. Calculated values for total Gc from the analysis showed good agreement for the three lay-ups and the three different test configurations. Using an assumed value for GIc from a previous study, the analysis was able to predict the delamination onset load for the cases considered. The result indicates that the opening mode component (Mode I) for delamination growth may be much larger than the component due to interlaminar shear (Mode II) from a matrix crack.
Failure Mechanism of Delamination Fracture
Authors: Lee SM
Published: February 2009

The failure mechanism of delamination fracture in composites is investigated. A model based on the fracture mechanics principles is applied to describe the in situ delamination failure process. The crack tip plastic zone developed in the thin resin layer between fibers is considered as the major energy dissipation mechanism. The model expresses delamination fracture toughness GIc (laminate), Mode I critical strain energy release rate, as a function of several resin properties. The delamination behavior of several epoxy/fiberglass systems was characterized using the width-tapered double cantilever beam method. The GIc (laminate) results are correlated with the resin properties based on the in situ failure model. Resin modulus E and yield stress σy are found to dictate the translation from GIc (resin) to GIc (laminate. Residual stresses in the laminates can also significantly weaken the delamination resistance. A comprehensive comparison between laminate and resin fracture toughness reported in the literature is analyzed from the viewpoint of the mechanism modelled.
The Use of Acoustic Emission to Detect the Onset of Interlaminar Shear Failure in Short Beam Fatigue Specimens
Authors: Edwards JH
Published: February 2009

Interlaminar shear failure caused by fatigue loading has been studied in carbonepoxy and glass-epoxy unidirectional composites. Short beam specimens were subjected to three-point bending loading with low mean stress, high mean stress, and zero mean stress at a range of alternating stresses to give lives in the range 104 to 107 cycles.

The indications of incipient failure given by acoustic emission were confirmed by ultrasonic Cscan and cutup. Of 150 specimens, only five failed to be confirmed by all three techniques.

After some initial trials to determine optimum gain levels and the addition of a voltage-controlled gate, acoustic emission proved simple to use, reliable, and accurate.
Damage Assessment by Acousto-Ultrasonic Technique in Composites
Authors: Lorenzo L , Hahn HT
Published: February 2009

This paper addresses the nondestructive evaluation of cross-ply [0/90]2s and [90/0]2s S-2 G1/DER 332 laminates using acousto-ultrasonic (AU) and acoustic emission (AE) techniques. Acoustic emission and acousto-ultrasonic measurements gave early warnings of damage initiation before transverse cracks became visible. AU parameters such as peak amplitude, energy, and stress wave factor were equally sensitive to damage initiation, but peak amplitude and energy were more sensitive to damage accumulation. Variations of peak amplitude, event duration, ringdown counts, and rise time in AU tests were analyzed to show that internal damage not only increased the apparent attenuation but also affected the wave envelope. The same effect was also present in AE tests. Acousto-ultrasonic tests of an undamaged cross-ply laminate showed that the apparent attenuation coefficients were almost independent of the wave propagation direction. The strongest wave was found along the fibers in the ply in contact with the transducers and the weakest wave traveled 45 deg to the fibers.
Standards for Computerized Laboratory Systems
Authors: Schilling PE
Published: February 2009

The ASTM standards for computerized systems are a readily available source of information about laboratory computerization. Generic Guide E 622 introduces a family of standards that describe a six-phase approach to acquiring or developing any type of computerized system. This approach can be used for systems that are developed from scratch, purchased as commercially available products, evolved through several generations of implementation, or developed from rapid prototypes.
Computerized Laboratory and Analytical Data Management System
Authors: Lukas M
Published: February 2009

Local area networks using personal computers have come of age. The features of such networks to share hardware, software, and data have made them an attractive and cost effective system which can be integrated into the operation of the typical metal analysis laboratory.

This paper is divided into two sections. The first section describes the basic building blocks of a local area network, their capabilities, and the key factors that must be considered in selecting a system for an analytical laboratory. The second section is an example of how to combine network technology with a software package to create a computerized laboratory and analytical data management system.
Implementation and Automation of Analytical Statistical Process Control
Authors: Linde TR
Published: February 2009

The goal of analytical statistical process control (ASPC) is to reduce process variability, which in turn will improve the quality of our products. In the case of laboratories, the products are analyses. The analyses, in turn, are used for process control and to verify that products meet customer specifications.

ASPC is implemented through use of control charts, which require a modest understanding of statistics. This paper briefly describes the practical side of developing and interpreting control charts. It also includes a discussion on what is needed to automatically maintain and interpret control charts for use with multi-element analyzers, such as optical emission (OE), X-ray fluoresence (XRF), and plasma spectrometers.
Quality Control System for X-Ray Analysis at Inland Steel Industries
Authors: Martin JE
Published: February 2009

Inland Steel Industries operates three X-ray units in two separate locations which provide routine analysis for blast furnace iron, blast furnace slag, sinter, iron pellets, and other raw materials on a 24 h basis. The original quality system's primary objective was to determine when the X-ray instruments needed to be recalibrated by the use of control samples. The original system generated enormous volumes of control data which were unmanageable without a computer data base. A system was developed using a TSO based cathode ray tube (CRT) terminal and a SAS data base. SAS/FSP (full screen product) screens are used to collect the data, and programs have been written to generate various statistics and plots. The new system has been in operation for approximately two years. It is used to generate daily reports on performance data and is used as a base for several internal check systems for the X-ray units. Because the data are readily available, it has been also used to solve various production problems. The data also can be presented in a statistical process control (SPC) format and have lead to the use of SPC control charts on the instrumentation and on the production samples.

The system completes its primary objective of X-ray control and provides many other benefits. These will be described in detail from data collection to finished reports and graphic plots. Future modification to the system will be also discussed.
Key Word Standardization in Vertebrate Pest Control
Authors: Timm RM , Salmon TP , Schmidt RH
Published: February 2009

Key words are becoming more useful as a means of locating bibliographic material. We expect their utility to increase as more persons use computers to store and retrieve information in data bases.

Previous ASTM Vertebrate Pest Control and Management Materials symposia proceedings have required the inclusion of key words; however, we have found that there is too much variability among these key words to enable them to be efficiently used. In the previous four symposia volumes, 104 articles used 469 different key words (\_-X = 7.38 key words per article). Only 12 key words were used more than five times and 375 were used once. We found many examples of synonymous key words. When used in computer information systems, this lack of standardization makes retrieval difficult or less productive.

We propose guidelines for choosing key words. Further, we give a suggested list of key words for articles dealing with vertebrate pest control. Use of these guidelines should lend a greater uniformity to information storage and retrieval in this field by aiding authors, editors, persons searching the literature, and persons developing their own data bases.
Surveys as an Approach to Gathering Animal Damage Information
Authors: Crabb AC , Salmon TP , Marsh RE
Published: February 2009

With limited resources available for vertebrate pest research and control, the use of surveys can be a cost-effective means of gathering certain kinds of data. Information from which to establish research priorities and for establishing control programs or modifying existing programs can be gathered with the careful use of surveys.

Three survey methods are most commonly used: telephone surveys, mailed questionnaires, and personal (face-to-face) interview-type surveys. Each method has its good points and specific shortcomings. The type of information desired, the number of responses needed for an appropriate sample, the geographic area encompassed by the survey, and resources available are major determinants of which survey type to use.

Special attention must be given to assure that biases are not produced by the nature of the survey, those conducting the survey, or those participating in the survey. Biases that do occur should be measured and acknowledged. Analysis of surveys can be made easier with the use of computer-based statistical packages such as Statistical Package for Social Sciences (SPSS) and Statistical Analysis Systems (SAS).

Experience with several types of surveys for gathering information and data are discussed along with an overview of some past uses of surveys in the field of vertebrate pest control and wildlife management.
Evaluating Corn Varieties for Resistance to Damage by Blackbirds and Starlings
Authors: Woronecki PP , Dolbeer RA , Otis DL
Published: February 2009

Because of many uncontrolled variables, it is difficult to study the influence of crop varieties and crop maturity on bird damage under field conditions. To achieve some degree of control in our evaluations of bird damage to corn, we constructed an outdoor aviary with 24 cages (1.5 by 5.0 by 1.0 m), each capable of holding up to ten birds. Racks designed to hold eight husked or unhusked ears of corn in a natural field position were constructed for the cages. This design allowed the evaluation of bird damage to field and sweet corn, controlling for such factors as bird species and sex, bird numbers, duration of damage, maturity of corn, and varieties. In addition, varieties could be tested under both free-choice (up to eight varieties) and no-choice (only one variety) regimes in replicated experiments. By measuring ear and husk characteristics, we could determine which characteristics were most closely associated with differences in damage among varieties. Varieties showing high degrees of resistance in the aviary could then be evaluated in replicated field experiments. With minor modifications, these procedures could be used to evaluate bird damage resistance in other agricultural crops.
Efficacy Testing of an Ultrasonic Bird Repeller
Authors: Griffiths RE
Published: February 2009

The efficacy of a combination sonic-ultrasonic device as a bird repeller was tested by comparing the activity, feeding time, and food consumption of common native birds at treated and control sites baited with sunflower seeds. The effect of the device on bird behavior at an unbaited site was also measured. Tests to date indicate that the device has no significant effect on the species studied. A method for testing the efficacy of repelling devices is proposed.
Levels of Strychnine in Poisoned Ground Squirrel Stomachs
Authors: O'Brien JM
Published: February 2009

Strychnine chopped cabbage bait has been used to control ground squirrels (Spermophilus spp.) in Nevada since 1975. The amount of bait present in the gastrointestinal tract of poisoned ground squirrels is unknown. One hundred forty-two stomachs of poisoned Richardson ground squirrels (S. richardsoni nevadenisis) were analyzed for strychnine. Strychnine averaged 2.3 mg (s = 2.4 mg, range 0.1 to 19.1 mg). In relation to kg bodyweight, strychnine averaged 13.0 mg/kg (s = 11.4 mg/kg, range 0.2 to 64.1 mg/kg).

Ground squirrel age, sex, body weight, and bait strength influenced (P < 0.05) strychnine mg. Age, bait strength (P < 0.01), and application rate (P < 0.005) influenced strychnine mg/kg.

Wide ranges in mg and mg/kg values may be due to other factors in addition to the variables examined. These factors include: bait distribution pattern, length of bait exposure, and susceptibility to strychnine.

Reducing application rate and bait strength lowered mg and mg/kg. Burrow baiting with 0.3% strychnine bait, 15 g per burrow, produced highest or intermediate levels of mg and mg/kg when compared to broadcast applications of 0.3% bait at 2.8 kg and 5.6 kg/ha.