bluuebunny/crossref_metadata_2025_split huggingface dataset:
Observations of Cracking Behavior in Tension and Torsion Low Cycle Fatigue
Authors: JA Bannantine , DF Socie 
Published: February 2009

A series of tension and torsion low-cycle fatigue tests were conducted on several engineering materials. Detailed observations of nucleation and early crack growth were made. Cracking behavior is shown to depend upon loading mode (tension or torsion), strain amplitude, and material type.
Multiaxial models developed for shear sensitive materials did not correlate multiaxial test results of a tension sensitive material. Differences in cracking behavior for different materials and loading conditions need to be considered in successful life predictions for components subjected to multiaxial fatigue.
Some Contributions to the Further Development of Low Cycle Fatigue Life Analysis Concepts for Notched Components under Variable Amplitude Loading
Authors: H Nowack , W Ott , J Foth , H Peeken , T Seeger 
Published: February 2009

In order to minimize the expenses of the development of engineering components and to reduce the risk of their operation, reliable fatigue life prediction methods have to be available in the design stage. Presently two groups of methods can be distinguished which explicitly account for the local stresses/strains in the fatigue critical areas: the so-called notch analysis concepts or “local approaches,” and new developments which are based on finite element methods (FEM).
In the first part of the paper typical areas in application of the notch analysis methods and some aspects of their further development are described. The significance of the short crack stage is briefly characterized from a physical and an engineering point of view.
In the second part the present state in the development of a new three-dimensional elasticplastic FEM-based fatigue analysis concept, FEMFAT, is described. FEMFAT uses a material model according to Mróz's proposal, and the fatigue damage is calculated on the basis of the plastic work as performed at the fatigue critical locations of components. A calculation scheme for the damage increments under arbitrary out-of-phase loading based on uniaxial data is proposed. Two examples of the application of FEMFAT are given.
Correlation Between Strain Singularity at Crack Tip under Overall Plastic Deformation and the Exponent of the Coffin-Manson Law
Authors: Y Murakami 
Published: February 2009

This paper is concerned with the interpretation of the Coffin-Manson law Δεp·Nfα=C [1] from the standpoint of the behavior of small cracks and also with the explanation of the uniqueness of the exponent α from the strain singularity at crack tip under overall plastic deformation.
Firstly, the characteristic behavior of small cracks in low-cycle fatigue range is discussed; then it is demonstrated that the Coffin-Manson law is virtually identical to the growth law of a small crack. This suggests that we must pay attention to the behavior of a small crack in order to solve low-cycle fatigue problems. Secondly, the singularity of strain field at crack tip is analyzed by a finite element method. It is well known that, denoting the distance from the crack tip by r, the elastic stress strain field near crack tip has the singularity of r−0.5 and under the elastic-plastic condition the stress and strain has HRR singularity. However, under overall plastic deformation (i.e., under low-cycle fatigue range) the singularity in strain distribution near crack tip deviates from HRR singularity to r−(0.5∼0.7) with increasing plastic deformation regardless of hardening exponents of materials.
It is concluded from the viewpoint of the propagation of a small crack that this exponent (0.5 ∼ 0.7) in singular strain distribution is closely related to the fact that the exponent α in Δεp·Nfα=C ranges from 0.5 to 0.7 for various materials.
Location of Potential Ground Subsidence and Collapse Features in Soluble Carbonate Rock by Remote Sensing Techniques
Authors: Kennie TJM , Edmonds CN 
Published: February 2009

The occurrence of subsidence and collapse dolines in soluble carbonate rock is a frequent geotechnical hazard throughout the world. Such features pose serious geotechnical problems to engineering and building construction and also to public safety.
Detection methods utilized during preliminary site investigations range from direct methods, such as drilling, to indirect methods, such as ground geophysics and airborne remote sensing.
The aim of this paper is to examine the role of remote sensing in these preliminary site investigations. Previous and current remote sensing research concerned with the location of solution features is reviewed, with particular emphasis on airborne multispectral and thermal infrared line scanning. A comparative assessment of the relative merits of the different techniques is given, together with an examination of the factors which influence whether a particular technique will be successful.
The authors recommend that the most favorable detection results will be obtained if remote sensing methods are used under optimum environmental conditions and in appropriate geological conditions.
A Satellite-Based Investigation of the Significance of Surficial Deposits for Surface Mining Operations
Authors: Leach JHJ , Mallett CW 
Published: February 2009

National Oceanic and Atmospheric Administration (NOAA) advanced very-high-resolution radiometer (NOAA-AVHRR), Landsat multispectral scanner (MSS), and shuttle imaging radar (SIR) imagery have been analyzed to determine their utility in evaluating parameters of geotechnical interest. This imagery has been used to determine the distribution, structure, and form of surficial deposits in the vicinity of large-scale mining operations. The data have been assessed in relation to specific problems encountered in large open-cut coal mines. The test sites chosen for this study are in the Bowen Basin of Queensland, Australia, where there are a number of very large open-cut coal mines. Some of these mines have slope stability problems in the pit walls and the spoil piles. Geotechnically important data on structural lineaments and the location and variation within surficial deposits have been acquired using these systems.
This paper presents the results of the study and points out the capabilities and limitations of the current satellite imaging systems. It also examines the potential of the next generation of satellite systems, such as the thematic mapper (TM) and Systeme Probatoire d'Observation de la Terre (SPOT), and discusses the characteristics of the ideal geotechnical remote sensing system.
Automated Design of Composite Plates for Improved Damage Tolerance
Authors: Gürdal Z , Haftka RT 
Published: February 2009

This paper is a first step toward automating the design for local damage tolerance of composite plates under compressive loadings simulating the local damage condition by a central through-the-thickness crack-like notch. Based on recent experimental investigations, the failure mode is assumed to be shear crippling, believed to be the result of kinking failure of the principal load-carrying fibers at a point of stress concentration in a laminate. The paper utilizes a microme-chanical failure model for the fiber kink formation in the load-carrying layers accounting for the combined effects of compressive and shearing stresses around the notch.
A previously developed code for cracked plates under tensile loading is used for the design purpose. The design code combines a finite-element analysis program with an optimization program and an automated mesh generation interface program. Minimum weight designs are achieved for stiffened and unstiffened plates subject to a constraint that a crack will not grow by fiber kinking failures. Design variables are ply thicknesses in different regions of the plates. Stiffened plates with four stiffeners that are assumed to be perfectly bonded to the plate section are considered. For stiffened plates, minimum weight configurations are obtained where the crack is isolated in low stiffness plate regions.
Characterizing the Tensile Stress-Strain Nonlinearity of Polyacrylonitrile-Based Carbon Fibers
Authors: Kowalski IM 
Published: February 2009

It is well known that carbon fibers exhibit nonlinear stress-strain behavior with their axial modulus increasing as they are strained. An empirical model is proposed to take into account this nonlinearity by adding a second-order term to Hooke's Law. This modified Hooke's law has the form σ = E0ε + Fε2. The tangent modulus is found by differentiating with respect to strain, giving Etangent = E0 + 2Fε. The tangent modulus increases linearly with strain.
Data are presented on three material forms—composite, impregnated strand, and single filament—to validate the empirical model. The E0 and F elastic coefficients are determined by performing a least-squares fit to the quadratic model. Data are generated for T-700 and T-40 high-strength polyacrylonitrile (PAN)-based carbon fibers. The nonlinearity of the fiber is shown to be comparable in single filaments, impregnated strands, and uniaxial composites.
The experimental results show that the empirical model provides an excellent fit to the stress-strain behavior of the carbon fiber. The E0 and F elastic coefficients are repeatable in various resin systems and differ for each fiber type. The elastic coefficients determined by this method should be used in the design of composite parts that see high loading in the fiber direction. As an example, the initial modulus of a T-40 fiber is 263 GPa (38.1 Msi) and increases to a secant modulus at failure of 308 GPa (44.7 Msi), and increase of 17%.
Galvanic Corrosion Caused by Corrosion Products
Authors: Wilhelm SM 
Published: February 2009

Experiments were conducted to quantify the magnitude of galvanic currents and potentials that exist between metals (iron, copper, titanium, aluminum, chromium, and nickel) and their corrosion products in oxygen-containing environments. Current measurements using a zero resistance ammeter and potential measurements of metal electrodes and oxide electrodes are reported. The effects of solution and electrode compositions on galvanic currents and potentials were determined. A galvanic series of corrosion products was constructed.
Galvanic interactions between metals and surface compounds are dependent on electronic conduction type (insulator, n-type, p-type, metallic) and thickness of corrosion product layers. It may be possible to modify semiconductor film conductivity by doping with impurity elements present as alloy constituents or via environmental addition and thereby mitigate galvanic corrosion.
Analysis of Microinclusions in Through-Hardening Bearing Steels
Authors: Lane S 
Published: February 2009

An automatic optical image analyzer, the Quantimet 800 Steelscan, has been applied for microinclusion assessment in bearing steels according to the Stahl Eisen Prufblatt (SEP) 1570/71 method. A brief description of the system is given, including the use of electronic image amendment to distinguish reliably between different types of oxides.
Although the SEP comparison chart is well-formulated and should be sensitive enough for inclusion assessment of present-day bearing steels, results are presented showing that manual assessments with this method should suffer from very poor reproducibility. The automatic method has provided a more reliable basis for discriminating different degrees of inclusion content and, as a consequence, has highlighted the difficulty in obtaining a representative measurement of microinclusion content, especially in worked material such as bar or tube. The effects of deformation by rolling, sampling errors due to material inhomogeneity, and small variations in the orientation of the plane of sectioning on the microinclusion K ratings are discussed.
The limitations of comparison chart methods and automatic image analysis systems are reviewed, with emphasis on the required sensitivity for assessing bearing steels, as compared with an accurate chemical analysis of impurity elements for the prediction of microinclusion content.
A Rapid Bioassay Using the Green Alga Selenastrum capricornutum to Screen for Toxicity in St. Lawrence River Sediment Elutriates
Authors: Ross P , Jarry V , Sloterdijk H 
Published: February 2009

A toxicity bioassay using the green alga Selenastrum capricornutum and measuring inhibition of photosynthetic carbon-14 (14C)-labeled carbon dioxide (14CO2) assimilation is described. The essential test specifications are the following:
(a) experimental vessels: 16-mL test tubes;
(b) exposure and incubation times: 20 h exposure plus 4 h incubation;
(c) dilution water: demineralized H2O;
(d) algal cell density: 1.9 × 105 cells mL−1;
(e) radioactivity: 0.072 µCi mL−1, as 14C-labeled sodium bicarbonate [Na2(H14CO3)2];
(f) nutrient enrichment: 1 mL of × 10 provisional algal assay procedure (PAAP) medium; and
(g) isotope partitioning: acidification and bubbling.
The resulting method is rapid, sensitive, and reliable (coefficient of variation &lt; 10%) and is applied to elutriates of St. Lawrence River sediments in an ongoing research project.
Effects of Complex Effluents on Photosynthesis in Lake Erie and Lake Huron
Authors: Bridgham SD , McNaught DC , Meadows C 
Published: February 2009

Phytoplankton are the base of the food chain in most large lake ecosystems; if affected by environmental pollutants, significant ecosystem changes can result with potential impact on higher trophic levels. This research determined the effects of a complex effluent discharge from the River Raisin in Monroe County, Michigan, on the Lake Erie ecosystem. This river flows through southern Michigan and has large nutrient and industrial inputs, especially in the Monroe Harbor area. The functional parameters measured were bacterial uptake rate of acetate, zooplankton feeding and reproduction rates, and primary production. The results of the effects of complex effluents on gross photosynthesis, measured as carbon-14 (14C) uptake, are presented in this paper.
Intensive sampling was undertaken during the ice-free seasons of 1983 and 1984. In 1983, water from various stations in the River Raisin was mixed with eutrophic Lake Erie water at several dilutions. The rate of photosynthesis in the mixed samples was compared with with that of a control composed of Lake Erie water only. No clear trend in photosynthetic response was evident with increasing percentages of river station water. In 1984, oligotrophic Lake Huron water was substituted as the control, resulting in massive stimulation in photosynthesis with increasing percentages of river station water. There were increased levels of nutrients, toxicants, and algal biomass in the harbor area in relation to the Lake Huron control. The 1984 data were evaluated again after being weighted for the relative biomass of algae as 14C uptake, so that a nutrient-toxicant interaction could be examined. Using these simple linear mixing criteria, a gradient in toxicity was found, with the upstream area of the river causing stimulation of photosynthesis while the harbor stations caused inhibition at all concentrations of effluent. Extensive chemical and physical analyses were done on the station effluents and controls. An analysis of covariance on the 1984 data indicated that no single toxicant was responsible for the inhibition of photosynthesis found in the harbor area.
Results suggest that, in complex effluent tests when an oligotrophic control is used with eutrophic effluents, a weighting factor for the relative biomass of algae must be used. Predictable trends occurred when this was done in relation to the Lake Huron control. Tributaries with diverse anthropogenic inputs, such as the River Raisin, have the potential for significant inhibition of primary production in receiving bodies of water.
An In Situ System for Evaluating Effects of Toxicants on the Metabolism of Littoral Communities
Authors: Lindblad C , Kautsky U , Kautsky N 
Published: February 2009

A portable in situ continuous-flow apparatus for measuring metabolic activities of littoral ecosystems is described. Oxygen, temperature, light, and flow rate are continuously monitored by a microcomputer that redirects the water flow through the measurement chamber from acrylic jars containing the communities. The apparatus is especially designed for experimental purposes, since it is possible to alter the incoming waters by adding various toxicants. The application of the method is presented by an example showing the response of a filter-feeding community to cadmium.
The community showed statistically significant changes in respiration (oxygen) and excretion (nitrogen or phosphorus) as a result of treatment. Calculated ratios—such as the oxygen/nitrogen ratio, oxygen/phosphorus ratio, and perturbation index (PI), which is the relative change due to treatment, taking into account changes in the controls—were more sensitive measurements of sublethal stress than specific values of oxygen, nitrogen, or phosphorus. These indexes are independent of biomass, and PI normalizes synchronic changes in the environment due to light, temperature, and salinity variations, which affect both treated and control systems equally. The design of the system allows the communities to be placed back in the environment after being tested and also allows repeated measurements to be made of possible delayed effects or recovery from perturbations. In this paper, the authors introduce a new measurement of disturbance, the absolute disturbance index (ADI). ADI is the absolute distance between the metabolic activity of an undisturbed system and a disturbed point in a multidimensional space where each dimension represents the PI of a measured parameter.
Rediscovering Marble and Natural Stone
Authors: Wood RC 
Published: February 2009

This paper deals with the application of thin-gauged marble and natural stone on the exteriors of buildings. The paper presents several methods of doing this, such as site applied over concrete and masonry surfaces and over lightweight steel studs using a wire-reinforced, latex modified mortar system.
The paper also presents the latest technology in exterior cladding utilizing lightweight steel panels, constructed off site where marble or natural stone may be applied to portland cement boards with a latex polymer modified mortar adhesive system. Detailed drawings of the applications are included as well as photographs of projects in various stages of construction.
Compositional Analysis of Light-Duty Motor Bearings in Fuel Pumps
Authors: Pamphilis NA 
Published: February 2009

A method of quantitatively determining a number of compounds in light-duty motor bearings has been developed. As a result, large amounts of carbon fibers (about 25% carbon) were found in samples containing polyphenylene sulfide (PPS), inorganic filler, and polytetrafluoroethylene (PTFE) by means of thermal analysis using both thermogravimetry (TG) and differential scanning calorimetry (DSC).
Two different, but related, methods were used to quantitatively determine the contents of the sample. The first, which was nominally called the “indirect approach,” uses DSC for the determination of the polymeric components and TG for the determination of the residue (inorganic fillers or glass). The amount of carbon is then determined based on the difference. The second method, which was nominally called the “direct approach,” uses DSC for the determination of PTFE and TG for the determination of all other components. The agreement between the two methods is good.
Usefulness of Fourier Transform Infrared Spectroscopy in the Analysis of Evolved Gas from the Thermogravimetric Technique
Authors: Khorami J , Lemieux A , Menard H , Nadeau D 
Published: February 2009

The usefulness of thermogravimetry has been amply demonstrated for a wide variety of analytical applications. However, in many instances, additional information is required for adequate characterization of the sample and its thermal decomposition behavior. In this respect, the analyses of evolved gases or condensed liquids has been proven a highly useful approach. Among the various physical methods used for the analyses of thermal degradation products, infrared spectroscopy has often been found very powerful, because it is versatile, rapid, and accessible.
In this study, we report a simple and new approach to recover evolved gases and condensed liquids after the thermal degradation of fibrous organic materials, using an infrared gas cell and a polyvinyl chloride (PVC) membrane filter, respectively. The gaseous components were analyzed by transmission Fourier transform infrared (FTIR) and the condensed liquids products were examined directly on the PVC membrane by FTIR in the internal mode.
For that purpose, several types of synthetic fibers have been selected: polyvinyl alcohol, polyacrylonitrile, polyaramids, and polyolefins. The decomposition products from the combustion of the organic fibers, both in the presence and absence of oxygen, are discussed.
PCBs: The Beginning, the Muddle, the End?
Authors: Manger HC 
Published: February 2009

Over the years, there have been many changes in the federal regulations regarding PCBs. From the beginning, utility personnel were in a dilemma as to how to deal with the problem.
First, we had trouble realizing that the askarel we were using in our transformers was more than 50% polychlorinated biphenyl, and even if it was, could it possibly be a toxic or a hazard to anyone's health? After all, we and those before us had been up to our elbows in the stuff for years. It may have burned our eyes a little, but as far as we know it did us no physical harm. We also found it was many things in our everyday life, at work and at home.
Soon those of use close to the situation realized that the utility industry, in particular, was in deep trouble. Congress passed the Toxic Substance Control Act in 1976 and singled our PCB to be controlled. Three years later EPA published the first of a number of rules that have changed the way utilities do business. The industry has been forced to spend millions of dollars and countless man-hours dealing with regulations that we questioned from the start and, at best, learned to live with. In addition, the rules change so often it is truly difficult to keep up with them.
This paper tries to take us from the start, thru the confusing muddle of regulations, to where we are today.
Methods for Evaluating Solidified Waste
Authors: Hannak P , Liem AJ , Côtè PL 
Published: February 2009

A number of methods for characterizing solidified waste are currently being assessed in the EC/EPA/AEC/Industry Cooperative Study. These are short-term laboratory tests which yield information on material properties (bulk density, specific gravity, and moisture content), ability to maintain physical integrity (unconfined compressive strength and weathering resistance—freeze/thaw and wet/dry), potentials for release of contaminants by advective transport (permeability) and dissolution (acid neutralization capacity, Toxicity Characteristic Leaching Procedure—TCLP—and equilibrium leaching), indication of long-term rate of contaminant release (dynamic leaching), and containment mechanisms (sequential extraction). A brief description is given of these tests, their rationale, and their utilization.
Some of the methods were developed elsewhere and have been adopted or adapted with minor modifications. Others have been developed specifically for the cooperative study. Emphasis is thus given to the latter, specifically to the method for quantifying resistance to wet/dry cycling. The development of this method and preliminary results are described, showing the reproducibility and ability to detect differences in weathering resistance of various solidified products.