bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Nonionic Surfactants on Properties of Water Dispersible Granule Formulations
Authors: Utz CG , Sekmistrz JM , Hollis RP 
Published: March 2009

Nonionic surfactants are not generally used in water dispersible granule formulations. Common dispersants for these systems include lignin sulfonates and naphthalene sulfonates. Recent studies have shown that ethylene oxide/propylene oxide (EO/PO) block copolymers can also be used to stabilize atrazine dry flowables in both pan granulation and extrusion processes. In laboratory tests, they impart better granule hardness and provide markedly improved suspensibility compared to the anionic dispersants. Most of the formulations tested show good particle size stability over time at room and elevated temperatures. Some particle size increase was seen in some formulations at 45°C.
Blends of these dispersants can be used to provide desired performance characteristics. Combining different ratios of nonionic and anionic dispersants impart varying properties to the granules. Increasing the amount of anionic surfactant can lower the particle size and reduce settling while maintaining the hardness and suspensibility obtained from the nonionic component. The performance of the anionic/nonionic blend in the granules is favorable when compared to the classical anionic formulation.
The molecular weight of the EO/PO block can also influence particle size (measured via wet screen analysis). As the total molecular weight is raised and the EO chain length thus increased, particle size decreases and suspensibility is improved. This result indicates a better dispersive capacity for the larger molecules.
In extruded granules, EO/PO blocks offer not only improved suspensibility and hardness but also equivalent particle size to an anionic dispersant. Obvious differences exist between surfactant performance in extrusion as opposed to that in pan granulation.
Improving Insecticide Activity and Rain-Fastness with Polyethylenimine
Authors: Feigenbaum HN 
Published: March 2009

Many surfactant or polymer-based adjuvants designed to improve the adhesion of active ingredients on plants function through mechanisms involving surface tension modification or hydrogen bonding. Polyethylenimine, a branched polyamine with high molecular weight and cationic charge density, offers a different adhesion promotion mechanism based on the formation of ionic bonds with anionic substrates combined with an ability to orient itself with organic active ingredients.
The product is particularly beneficial with pesticide actives which function through a contact mechanism and demonstrates an ability to improve pesticide efficacy particularly in terms of rain-fastness, adhesion, heavy metal complexation, biodegradation, and initial fixation level.
In Situ Bioremediation Pilot Study at a Former Manufactured Gas Plant Site
Authors: English DA , Nelson JR , Hargens DA 
Published: March 2009

A one-year in situ bioremediation pilot study was implemented in January 1992 at a site contaminated with polynuclear aromatic hydrocarbons, benzene, ethyl benzene, toluene, and xylenes from former manufactured gas plant operations. The objective of the study was to evaluate the effectiveness of in situ bioremediation on high molecular weight hydrocarbons under site conditions.
The pilot study involved injecting treated groundwater amended with nutrients and oxygen (in the form of hydrogen peroxide) into the subsurface via an injection well, extracting groundwater through a downgradient extraction well, and periodically monitoring the system using monitoring wells and soil borings.
Results indicate that the site hydrogeology, the high concentrations of target and non-target organics, and the presence of pure-phase coal tar in the subsurface limit the cost-effective application of in situ bioremediation at this site.
Bioremediation Application in the Cleanup of the 1989 Alaska Oil Spill
Authors: Lessard RR , Wilkinson JB , Prince RC , Bragg JR , Clark JR , Atlas RM 
Published: March 2009

Following the Valdez spill in Alaska in 1989, Exxon scientists worked closely with the U. S. Environmental Protection Agency (EPA) and the State of Alaska, to conduct the most extensive bioremediation study on oiled shoreline ever carried out. Over $10 million was spent conducting this research. The process involved applying fertilizers on intertidal shorelines to stimulate the growth of indigenous oil-degrading microbes and accelerate the rate of natural degradation of the oil. In analyzing the data from this program, Exxon developed unique approaches, focusing on specific changes in the oil chemistry to verify the degradation rate increase provided by the added nutrient. Such a sophisticated approach was required because of the problems inherent with measurement of total petroleum hydrocarbon in the sediment to define the degradation rate. Results show that the rate of oil biodegradation on fertilized beaches was from three to more than five times faster than on unfertilized beaches.
This paper summarizes the bioremediation research conducted, and the extensive information obtained. The experience gained by Exxon, including pioneering work on internal markers, applies directly to bioremediation studies in other environments. Some of this experience is being extended to the remediation of inland contaminated sites and there is a major effort now underway to identify low-cost bioremediation techniques for in-situ restoration of such sites.
Establishment of Fatigue Test Method for Turbine Blade Fastener
Authors: Endo T , Kondo Y , Kadoya Y 
Published: March 2009

The design of a long, wide blade for a large-sized steam turbine required the development of new design methodology. The most important consideration to ensure the integrity of a blade attachment is to evaluate the stress at the local point of a blade root. The major difficulties in stress evaluation are the three-dimensional effects and the contact problem at the fastening point between the blade root and the disk steeple. Because of these complexities, the design method based on the linear elastic finite-element method (FEM) analysis has to be verified experimentally.
For this purpose, a new fatigue testing apparatus was developed that simulates the operating loads for the steam turbine, including centrifugal forces, untwisting moments, and bending moments. The results of the strain measurement and the low-cycle fatigue tests verified the use of the peak stress, which was calculated by three-dimensional elastic FEM analysis using linear elastic connection of blade root and disk steeple and Neuber's rule for the evaluation of the strain range. If the strain is evaluated correctly, the low-cycle fatigue life can be obtained using a Langer's-type equation.
Mixed Mode Interlaminar Fracture Toughness of Unidirectional Glass/Epoxy Composite
Authors: Gong X-J , Benzeggagh M 
Published: March 2009

The objective of this work is to evaluate the interlaminar fracture toughness, in terms of the total critical strain energy release rate (GTc), for unidirectional glass/epoxy composites under mixed Mode I + II loading. Several bending tests proposed in the literature, such as the DCB, MMF, ENF, and CLS tests, were performed. In addition, the mixed mode CBON and IDCB tests were developed. The combination of these tests gave fracture toughness results that covered a complete mixed mode range: 0 ≤ GII/GTc ≤ 1. The GTc and the individual components, GI and GII, were determined analytically by the beam theory and by finite element calculation. Measurements of these parameters using experimental compliance calibration were compared with the analytical results to ensure their validity. Both the testing and analytical methodologies are discussed. The influence of specimen configuration on the GTc values was also investigated. Fractography provided a way to understand the fracture mechanisms and to associate the fracture surface morphology with the variation of the GTc.
Based on experimental data obtained, a new mixed mode delamination criterion has been proposed.
Non-Penetrating Impact Behavior of CFRP at Low and Intermediate Velocities
Authors: Delfosse D , Poursartip A , Coxon BR , Dost EF 
Published: March 2009

A series of instrumented impact tests have been carried out using two different CFRP laminates, IM6/937 with a relatively brittle matrix and T800H/3900-2 with a toughened matrix. Two impactor masses differing from each other by a factor of 20 were used to study the effect of impact velocity and rate of loading.
Differences in the target impact response were found when the panels were impacted with the same energy but at different velocities. The higher velocities led consistently to slightly higher measured peak forces, but lower maximum deflections. This difference is reflected in the resultant damage state. The measured delamination area is larger for the high-mass impacts at the same incident impact energy, particularly for the tough matrix system. However, when the delamination size is correlated with the impactor energy loss, the mass effect disappears. The low-mass, high-velocity impacts create large contact forces, which leads to significant fiber breakage on the impact face. Fiber breakage throughout the rest of a panel is lower, which can be explained by the lower maximum panel deflections observed in low-mass impacts. An energy balance that takes into account the work done in delamination and fiber breakage gives good agreement with the measured impactor energy loss over the complete range of impact energies tested.
Modeling Crack Growth Resistance Using Computational Cells with Microstructurally—Based Length Scales
Authors: Shih CF , Xia L 
Published: March 2009

Many metals which fail by void growth mechanism display a macroscopically planar fracture process zone of one or two void spacing in thickness characterized by intense plastic flow in the ligaments between the voids. To model this process cell elements, each of which contains a void, are employed on the plane ahead of the initial crack. The linear dimension of these elements is D. We use Gurson model to describe the hole growth in a cell resulting in material softening and, ultimately, loss of stress carrying capacity leading to void coalescence and formation of new crack surface thereby advancing the crack. The void-free material surrounding the cells is described by the J2 flow theory of plasticity. The two cell parameters, D and f0, characterize the mean spacing and volume fraction of voids in the material lying in the plane of fracture.
Finite element calculations have been carried out for plane strain, mode I crack growth under small scale yielding. A wide range of fracture behavior is captured by proper combinations of D and f0 Resistance curves are calculated for crack extensions two orders of magnitude larger than D. The parameters affecting fracture resistance are discussed emphasizing the roles of microstructural parameters and continuum properties of the material. Geometry effects on fracture resistance are investigated by way of the T-stress. As a final application, resistance curves for a deep and a shallow crack bend bar are computed. These are compared with experimental data.
The Second Parameter in J-R Curves: Constraint or Triaxiality ?
Authors: Brocks W , Schmitt W 
Published: March 2009

J-R curves are used to assess the stability of growing cracks in ductile materials. Since initiation and crack-extension resistance are geometry dependent any transfer of the measured data to a structural component is subject to the individual responsibility of the engineer. The introduction of a second parameter for failure assessments beyond J-control has, therefore, been widely discussed, recently, and different approaches have been used to quantify the local stress triaxiality and crack tip constraint. Three basic ideas underlie these various approaches, — including higher order terms in the analysis of asymptotic fields at the crack tip, — utilizing the J-CTOD relationship as a measure of crack tip constraint,-considering micro-mechanisms of ductile failure.
Before adding new results of tests or calculations to the existing ones it seems worthwhile to discuss the different concepts with respect to their advantages and drawbacks, limitations and generality of application, physical evidence, etc. It seems that constitutive models of damage have the highest degree of physical evidence and generality of applications. “Constraint effects” do not even arise as separate problems since triaxiality of stresses enters the model directly. The investigation of micro-mechanical mechanisms helps to identify significant parameters.
Air Leakage in the Perspective of International Standards
Authors: Levin PA , Wilson DJ , Ackerman MY 
Published: March 2009

There exist a number of national standards and a draft international standard for the fan pressurization method for measuring air leakage. Although the standardized methods in principle are the same, the way of interpreting and presenting the results is different.
In previous studies, houses that have a relatively large leakage area at a low pressure difference (4 to 10 Pa) still can seem comparatively airtight at a high pressure difference (50 Pa). This fact is a consequence of differences in the flow exponent in the power-law equation, which is the normal equation used to fit to the data points, and can be a source of error when trying to compare the relative airtightness of houses. Extrapolating results from high pressure differences to low pressures, which are out of the measured range, can thus result in substantial errors. Air leakage testing of windows normally starts at 50 Pa, which should be accounted for when trying to use these results as inputs in network air infiltration models. Measurement results on low pressure air leakage are discussed in the paper and compared with high pressure air leakage.
Pressurization test data from 105 tests in one house at the Alberta Home Heating Research Facility are used for the study. The tests were made automatically over a seven-month period in low wind conditions. A wide range of pressure differences were tested and the results cover the test specifications for most standards. In addition to comparing standards, these tests were used to measure seasonal effects on air leakage in a wood-frame house with a plastic film air/vapor barrier.
The results show some significant differences between the standards, and also a variation with month of test, indicating a seasonal variation in air leakage.
Measured Airtightness of 24 Detached Houses over Periods of up to Three Years
Authors: Proskiw G 
Published: March 2009

Regular airtightness tests were performed on 24 new houses, over periods of up to three years, to evaluate their air barrier systems and to search for evidence, air barrier degradation. Ten of the houses were constructed with polyethylene air barriers while the remaining 14 used an early version of the Airtight Drywall Approach (ADA). The 24 project houses were architecturally similar and of approximately equal size and general layout; stucco was the predominate exterior wall finish. All were exposed to similar terrain shielding.
The study found that the airtightness of the polyethylene air barrier houses remained stable over their respective monitoring periods. Although two of the ten houses demonstrated possible, albeit slight, evidence of airtightness degradation, the magnitude of these changes was small and judged not to be of practical significance. With respect to the critical issue of air barrier degradation, no evidence could be found to indicate polyethylene is unsuited for use as an air barrier material in residential construction. For example, all but one of the polyethylene houses met the airtightness requirements of the Canadian R-2000 Standard for energy efficient housing at the end of their monitoring periods.
The study found that the airtightness of the 14 ADA houses also remained stable over their monitoring periods. Although six of the 14 houses displayed possible, but slight, evidence of airtightness degradation, the magnitude of the changes was small and not of practical significance. It was concluded that no evidence could be found to indicate that the ADA system is unsuited for use in residential construction. All 14 ADA houses met the airtightness requirements of the R-2000 Program at the end of their respective monitoring periods.
European Insulated Glass Unit Testing
Authors: Lowe GB 
Published: March 2009

The European Community is pledged to reach a situation where there is no technical barrier to trading between the community partners. To this end the Commité European de Normalisation (CEN) committee TC129 — Glass in Buildings was set up. The Working Group WG4 has the specific task of writing a specification for Insulating Glass Units.
The instructions to the committee were that any insulating glass units currently meeting there own national standard should not be disadvantaged, at least in the first instance, by not being able to meet the new specification.
Naturally National views were put forward in the early stages, and there has been a period of intense negotiation, and compromise, before the specification started to take shape.
The current situation is that although not complete, the specification is now taking shape and a series of Round Robin comparisons have been carried out to verify the tests included.
Laboratory Effectiveness Testing of Water-in-Oil Emulsion Breakers
Authors: Fingas MF , Fieldhouse B , Bier I , Conrod D , Tennyson E 
Published: March 2009

The physics and chemistry of water-in-oil emulsions dominate the development of effectiveness tests. Emulsions are variable in stability ‐ this variability is largely dependent on oil type and degree of weathering. These factors complicate the development of a test. Emulsions which have low stability will apparently break easily with chemical emulsion breakers. Broken emulsions will form a foam-like material, called “rag”, which retains water which is not part of the stable emulsions.
Analytical methods used to determine the final stability of the broken or unbroken emulsion were evaluated. Measurements of water content and viscosity measurements show correlation to emulsion stability. Viscosity provides a more reliable measure of emulsion stability but water content measurements are more convenient and are largely used in this study.
Twelve tests were developed in the past. Two testing methods have been developed to a usable stage. These tests are described and data using them provided. The effects of mixing time, agent amount, settling time and mixing energy on effectiveness results are presented.
Computerized Materials Data Integration in an Air Force Analytical Design Package
Authors: Mack TE , Whitney TJ , Kipp TE , Gran MG 
Published: March 2009

To exploit the benefits of concurrent engineering and avoid the usual problems associated with nonconforming materials, an Air Force program for creating an aircraft transparency design engineering workstation, ADP2 (Analytical Design Package), was structured around a materials data server (M/VISION coupled with PATRAN). The data server at the core of the system is used to integrate a variety of applications and databanks, both commercial off-the-shelf (COTS) and special purpose items developed by the Air Force and the University of Dayton Research Institute (UDRI). It provides the focal point for loading, processing, cataloging and transferring of data between the various applications.
As a part of the frameless transparency program (FTP), ADP2 is a design tool consisting of existing analysis codes and computer aided engineering (CAE) software. The objective of ADP2 is to develop an integrated design methodology for frameless transparencies, aircraft interfaces, and their corresponding tooling. The scope goes all the way from materials testing through design and analysis to manufacturing and full life cycle maintenance. Several categories of materials data are handled, including raw test data, manufacturer's product data, evaluated property and specification data (such as from Military Handbooks), synthesized or simulated properties data, as well as data on service history. The functional environment requires multiple iterations through the design process with evolving materials properties and processing parameters for various testing, manufacturing, and analysis environments.
The basic features of the ADP2 system and the development process are described. Insight into how the system is used is given by virtue of an example involving the materials data integration module. The incorporation of technology and concepts from evolving standards like ISO/STEP and ASTM Committee E49 on Computerization of Material and Chemical Property Data proved very beneficial.
Constraint Effects Observed in Crack Initiation Stretch
Authors: Lambert DM , Ernst HA 
Published: March 2009

The current paper characterizes constraint in fracture: J-modified resistance (JMR) curves were developed for two tough structural materials, 6061-T651 (aluminum) and IN718-STA1 (nickel-base superalloy). A wide variety of configurations was tested to consider load configurations from bending to tension including three specimen types (compact tension, center-crack tension, and single-edge notched tension), and a range of ligament lengths and thicknesses, as well as side-grooved and smooth-sided ligaments.
The JMR curves exhibited an inflection point after some crack extension, and the data were excluded beyond the inflection. Qualified JMR curves for the two materials showed similar behavior, but R-curves were identical for equal ligament length-to-thickness ratio, RL, for the aluminum alloy, with increasing slope for increasing RL, while for the nickel, the resistance curves aligned for equal ligament thickness, B, and the slope increased for decreasing B.
Displacements at the original crack tip (δ5) were recorded throughout the test for several specimens. δ5-versus-crack extension curves were developed, and data were excluded beyond the inflection point (as with the JMR curves). The data collapsed into two distinct curves, thought to represent the surface, plane stress effect and the central, plane strain effect. This was observed for both materials.
A technique called profiling is presented for the aluminum alloy only, where the crack face displacements are recorded at the final point of the test as a function of the position throughout the crack cavity, along with an effort to extract the observations in a usable form. Displacements were consistent throughout the cross-section at and behind the original crack tip. In the region where the crack grew, this displacement was developed by a combination of stretch and crack growth. The stretch required to initiate crack extension was a function of the depth beneath the surface into the cross-section.
Investigation of Fracture Mechanical Behaviour of Nodular Cast Iron and Welded Joints with Parent-Material-Like Weld Metal
Authors: Baer W , Pusch G 
Published: March 2009

The focus of the investigations was the determination of fracture mechanical characteristics and crack resistance curves of the J-Integral and CTOD concept by application of the partial unloading compliance technique and D.C. potential drop technique (four point bend) under static load.
The results show a close correlation between crack initiation values as well as crack resistance curves and graphite morphology parameters determined by means of quantitative microstructural analysis where the influence of the matrix (distance of graphite particles) dominates the crack resistance and fracture performance of ferritic nodular cast iron under consideration of the notch effect of graphite particles.
SEM in-situ tensile tests showed that due to a beneficial shielding effect of the strength overmatching parent-material-like weld metal (mis-match ratio M=1.21), cracks positioned directly in the plane of the fusion line did not deviate into the weld metal in spite of its lower toughness compared to that of the parent material. They also showed an unsymetrical formation of damage in front of the crack tip.