bluuebunny/crossref_metadata_2025_split huggingface dataset:
The comprehension skills of children learning English as an additional language
Authors: Burgoyne K. , Kelly (née Hutchinson) J. M. , Whiteley H. E. , Spooner A. 
Published: March 2009

Background Data from national test results suggests that children who are learning English as an additional language (EAL) experience relatively lower levels of educational attainment in comparison to their monolingual, English‐speaking peers.Aims The relative underachievement of children who are learning EAL demands that the literacy needs of this group are identified. To this end, this study aimed to explore the reading‐ and comprehension‐related skills of a group of EAL learners.Sample Data are reported from 92 Year 3 pupils, of whom 46 children are learning EAL.Method Children completed standardized measures of reading accuracy and comprehension, listening comprehension, and receptive and expressive vocabulary.Results Results indicate that many EAL learners experience difficulties in understanding written and spoken text. These comprehension difficulties are not related to decoding problems but are related to significantly lower levels of vocabulary knowledge experienced by this group.Conclusions Many EAL learners experience significantly lower levels of English vocabulary knowledge which has a significant impact on their ability to understand written and spoken text. Greater emphasis on language development is therefore needed in the school curriculum to attempt to address the limited language skills of children learning EAL.
Polymer science applied to petroleum production
Authors: Lucas Elizabete F. , Mansur Claudia R. E. , Spinelli Luciana , Queirós Yure G. C. 
Published: March 2009

Abstract
The science of polymers, more specifically, synthesis, characterization, and physicochemical properties in solutions, has wide application in the petroleum industry, which uses polymers as components of fluids or additives to correct problems that affect oil production and/or increase production costs. Polymers are utilized during all phases, from drilling to treatment of oil and water. Research on the synthesis of polymers and their respective characterization aims to develop new molecules, with controlled structures, for various applications, having one or more objectives, namely: (1) to enhance operating efficiency; (2) to reduce costs; and (3) to elucidate mechanisms of action that can help in the development of new technologies. The evaluation of the physicochemical properties of a polymer in solution in many cases permits establishing useful correlations between its properties and performance in a specific application, besides providing insight into the mechanisms inherent in the production system, as is the case of stabilization of asphaltenes. Our research group has applied the knowledge of polymer science to the petroleum industry, focusing on the following functions: viscosification, inhibition of clay swelling, formation of filter cake, drag reduction, divergence, modification of wax crystals, stabilization of asphaltenes, emulsification, demulsification, and cleaning of solids systems contaminated with petroleum, among others.
Hydrophobicity recovery of corona-modified superhydrophobic surfaces produced by the electrospinning of poly(methyl methacrylate)-graft-poly(dimethylsiloxane) hybrid copolymers
Authors: Swart Morne , Mallon Peter E. 
Published: March 2009

AbstractSuperhydrophobicity is dependent on both the surface energy and the texture of the surface. These factors are discussed in terms of a series of electrospun poly(methyl methacrylate)-graft-poly(dimethylsiloxane) (PMMA-g-PDMS) copolymers with different poly(dimethylsiloxane) (PDMS) content. These copolymers are synthesized via conventional free radical copolymerization of methyl methacrylate (MMA) and monomethacryloxypropyl-terminated PDMS macromonomers. It is shown how these copolymers can be electrospun to produce copolymer fibers with diameters in the 100-1000 nm range. The effect of the copolymer composition (and hence the surface energy) and the electrospinning tip-to-collector distance (TCD) on the fiber morphology is discussed. The surfaces produced by the electrospinning process show superhydrophobic properties where the preferential surface segregation of the PDMS component is combined with the roughness of the fiber surface. The surface energy of the fibers is varied by variation of the PDMS content in the copolymers as well as by post-spinning modification with corona discharge. The hydrophobicity of the surfaces shows a greater dependence on the PDMS content than on the average fiber diameter. After exposure of these fiber surfaces to corona discharge, the initial superhydrophobic surfaces become easily wettable despite the fact that much of the surface roughness is maintained after exposure. The samples show the phenomena of hydrophobocity recovery after corona exposure. The rate and extent of this recovery depends on the PDMS content and the corona exposure time. Despite the recovery, scanning electron microscopy (SEM), swelling measurements, and confocal Raman spectroscopy show that permanent surface changes have taken place. The surfaces do not recover to their original superhydrophobic state.
The Use of Full-Scale Testing for Establishing and Validating Structural Performance Requirements
Authors: Yancey CWC 
Published: March 2009

Two test programs performed by the National Bureau of Standards (NBS) in 1970 and 1971 on wood-framed houses are discussed as cases in point of the use of full-scale testing for establishing and validating structural performance requirements.
In one study, field tests were conducted on an as-built single-family detached house to measure its deflection characteristics under lateral loading. The test data were used to determine whether the drift limitations required in the design of medium- and high-rise buildings are applicable to low-rise buildings. A series of tests was conducted to determine the stiffness of the house when subjected to simulated wind loading. Load was applied alternately at the second floor level and at the eave line of the two-story house. Horizontal and vertical movements of the building were measured at discrete points on the two levels, for the two loading applications and superposition was used to determine the combined effect. As a result of the two test series, it was concluded that: “The measured second-story drift for the house was considerably less than that derived using the drift limits specified for medium- and high-rise buildings in most areas of the United States.”
In the second study, a series of laboratory tests was conducted on a 3.7-m wide by 18.3 m long (12-ft wide by 60-ft long) factory-built housing module. The tests were to determine the strength and stiffness of a typical wood-frame housing unit and to provide baseline data against which the performance of less traditional construction could be compared. Four of the six tests in the series involved the application of lateral load: (1) monotonic racking, (2) repeated racking, (3) reversals of racking, and (4) racking of capacity. Load was applied perpendicular to the long walls at the eave line of the one-story module using a series of hydraulic jacks to simulate the effects of either wind or earthquake loading. Horizontal and vertical displacements were measured at a number of discrete points. The measured response at various design load levels was compared to the limit states specified in design criteria prepared by NBS for the U.S. Department of Housing and Urban Development's (HUD) Operation Breakthrough. Based on an analytical model used to condition the test results, it was concluded that 1.01 kN/m2 (21 psf) was the maximum static wind pressure at which the housing system could satisfy the conventional drift limitation (that is, h/500, where h connotes height above ground level) applied to medium- and high-rise buildings.
Skyline Plaza North (Building A-4)—A Case Study
Authors: Dixon DE , Smith JR 
Published: March 2009

The dynamic collapse of a portion of Building A-4 of the Skyline Plaza Project at Bailey's Crossroads, Va., predicated an extensive investigation of the remaining structure to determine its salvageability. As part of this investigation two types of load tests were performed. Column shear load tests were made in a portion of the structure which was being demolished. These tests were performed to estimate the shear capacity of the flat plate slabs at the columns. Basically, the tests involved isolating the test area around the column by saw cutting the concrete slab. The isolated slab section was loaded in increments until failure using eight post-tensioning rams reacting against the column two floors down. Load-deflection data were used to compute the appropriate shear value.
Several static load tests of the slabs were also performed. These tests utilized the loading criteria given in Chapter 20 of the American Concrete Institute's (ACI) 318-71, “Building Code Requirements for Reinforced Concrete.” Water was used for the required loads with the depth of water and deflection of the slab under load monitored by remote instrumentation. In several cases the loaded areas were more than one-half of the total floor slab area.
Disposal Systems for Oil Recovered from Marine Spills
Authors: Hansen WG , Ross DE , Sinclair JR 
Published: March 2009

An on-going study sponsored by the U.S. Coast Guard, Office of Research and Development, is being conducted by SCS Engineers to assess the capabilities and shortcomings of existing disposal systems for oils and oil-debris mixtures recovered from spills. Research objectives are to provide a comprehensive description of existing collection, storage, transfer, treatment, and disposal equipment for possible Coast Guard procurement and to conceptualize needed new equipment and systems for Coast Guard-sponsored research and development.
Project results indicate that developed systems have been designed for specific environmental and debris conditions and may not provide the flexibility for the various situations experienced during Coast Guard operations. Yet equipment is available that can be included in general systems for disposal of oil spill debris under a wide variety of environmental conditions. Seventeen systems utilizing such equipment are defined and assessed in terms of on-site capabilities, deployability, cost, and other factors.
Selection of Oil Spill Landfill Disposal and Temporary Storage Sites Along the Beaufort Sea Coast
Authors: Robson W , Blackall PJ 
Published: March 2009

A study was performed to locate landfill disposal and temporary storage sites for oiled debris from sand and shingle beaches along the Beaufort Sea Coast from the Alaska-Yukon border to Cape Bathurst. Approximately 217 landfill disposal sites and 223 temporary storage sites have been located. These sites are shown on 1:150 000 scale strip maps and on 1:20 000 to 1:70 000 scale aerial photographs in the report.
This study involved establishing guidelines for site selection, design, construction, and reclamation for landfill disposal sites, temporary storage sites, and access roads. Limitations on construction, utilization, and reclamation due to seasonal problems with terrain stability, logistics support, and cost effectiveness were considered. All of the sand and shingle beaches in the study area were identified using aerial photographs, and these beaches are shown on 1:150 000 scale strip maps. In addition, alternative or novel landfill disposal and temporary storage techniques are reviewed.
Historical Consideration of Interspecies Relationships in Toxicity Assessment
Authors: Zapp JA 
Published: March 2009

The survival of earliest man depended on recognition and avoidance of those plants and animals which were posionous by contact or ingestion. But early man also found that poisonous plants and animals could be used to advantage in hunting and in killing his enemies. References to poisoned arrows are found in both the Old Testament and the early writings of Homer.
Man's earliest knowledge of toxicology came from direct observation and experiments on man. When, at a later period, experimentation on humans became unpopular and illegal, man experimented on animals such as the dog, cat, and rabbit to gain some insight into probable toxicological effects of substances on man. The transfer of data from one species to another requires extrapolation which, although the techniques have been greatly refined, always embodies a degree of uncertainty. Animal experimentation, however, with the application of arbitrary safety factors, remains the basis on which regulatory agencies reach a decision as to the safety of foods, drugs, cosmetics, pesticides and environmental contaminants. For practical purposes it has worked rather well.
Comparison of Heavy Metal Interactions in Acute and Artificial Stream Bioassay Techniques for the Asiatic Clam (Corbicula fluminea)
Authors: Rodgers JH , Cherry DS , Graney RL , Dickson KL , Cairns J 
Published: March 2009

Population densities of the Asiatic clam, Corbicula fluminea, in the thermally influenced areas of the New River at the Glen Lyn power plant, Glen Lyn, Va., increased from zero before 1975 to approximately 11 522/m2 by February 1978. Since their establishment, clams in the thermal effluent have served as a source of propagules for clam invasion into other areas of the New River during the warmer seasons.
Copper was more toxic (LC50 = 0.04 ppm) to the clam than zinc (LC50 = 6.04 ppm) or copper-zinc simultaneously (LC50 = 0.05 ppm) in 96-h static bioassays. Ninety-six-h LC50 determinations in artificial stream bioassays were at least one order of magnitude higher when compared with the static test values (the LC50 values for copper and copper-zinc combined were 0.49 and 3.06 ppm, respectively). The LC50 values appeared also to be the effective concentration at which at least 50 percent of the clams demonstrated a gaping response and cessation of filtering activity. Elemental bioaccumulation of copper and zinc was more prevalent in the visceral tissue than in concentrations measured from clam valves or from the water in both laboratory bioassays and field determinations. When copper bioaccumulation in the viscera increased to approximately 275 to 400 ppm, gaping and a lack of filtering activity were evident in 96-h tests. Behavioral mechanisms—cessation of filtering activity and the closure of valves during stress—were considered to be likely factors in producing the higher LC50 values, when compared with other invertebrate responses.
Allometric Growth Response of Exercised Rainbow Trout to Cyanide Poisoning
Authors: McCracken IR , Leduc G 
Published: March 2009

The toxicity of cyanide to juvenile rainbow trout held in swimming chambers during 20-day growth experiments at 10°C was found to be size related, the larger trout being more adversely affected than the smaller ones.
The results of four experiments on control and cyanide-exposed trout forced to swim against a constant current speed of 12.1 cm/s while being fed restricted rations revealed that cyanide at 0.01 mg/litre hydrogen cyanide (HCN) increased the food maintenance requirement of the large fish, which were growing less rapidly than their respective controls. The smaller fish, however, grew faster than their controls when exposed to cyanide because of a faster accumulation of lipids.
The metabolic rate of fish is related to size, and this relation is described by the allometric formula Y = aXb, where Y is the metabolic rate, X the body size, a the Y-intercept, and b the weight exponent and slope. This formula was applied to the present results, and a log-log plot of dry weight gains against initial wet weights provided a linear relationship describing the metabolic rates of the control and poisoned fish. The slope representing the controls was 1.12, indicating a metabolic rate function of the weight of the fish, whereas the slope representing the cyanide-poisoned group was 0.67, thus describing a metabolism proportional to the surface area of the fish.
This study brings to light the determining influence of factors modifying the metabolic rate, such as exercise and size, on the response of fish to a toxicant.
Heavy Metal Stress and Increased Susceptibility of Steelhead Trout (Salmo gairdneri) to Yersinia ruckeri Infection
Authors: Knittel MD 
Published: March 2009

Steelhead trout exposed to zinc concentrations as high 98 ppb did not demonstrate increased susceptibility to Yersinia ruckeri infection. Exposure to cadmium at 0.9 ppb did enhance susceptibility to infection; however, the exposure level was near the LC50 for cadmium against steelhead trout.
Exposure of steelhead trout to copper concentrations as low as 2.0 ppb, which is considerably below the LC50 for steelhead trout, increased their susceptibility to Y. ruckeri infection. The time of exposure to the 10 ppb copper showed that maximum infection occurred after 48 h of exposure; however, a 12-h exposure could increase infection in the host fish.
Results of this research show that the study of specific stress in fish caused by exposure to certain toxicants may be best studied by determining their susceptibility to a pathogen.
A Dynamic Photoelastic Study of Crack Propagation in a Ring Specimen
Authors: Dally JW , Shukla A , Kobayashi T 
Published: March 2009

Crack propagation in a thick-walled ring specimen subjected to a mechanically simulated thermal stress was investigated by employing dynamic photoelasticity. Ring models fabricated from Homalite 100 were loaded with a specially designed mechanical deformeter which separated and rotated a slit cut into the ring to produce a combination of tension and bending that simulated a steady-state thermal stress.
Short starter cracks were machined into a series of ring models and the deformeter adjusted to give KQ/K1m ranging from 1.2 to 3.0. The crack was initiated and high-speed photographs of the isochromatic fringe loops at the tip of the running crack were recorded. The data were analyzed to obtain the instantaneous stress-intensity factor K, the normalized crack position a/w, and the crack velocity ˙a.
The relation between K and ˙a was established for Homalite 100 using the ring specimen. It was noted that this K-˙a relation compared well with those determined previously using single edge notch, rectangular double cantilever beam, contoured double cantilever beam, and modified compact tension specimens.
A comparison of K, as a function of position a/w, was made between static and dynamic crack growth. A marked difference was noted. For static crack growth, K increases with a/w until a/w = 0.2 and then decreases with further crack extension. For dynamic crack growth, K decreased monotonically with increasing a/w.
Critical Examination of Battelle Columbus Laboratory Crack Arrest Toughness Measurement Procedure
Authors: Fourney WL , Kobayashi T 
Published: March 2009

Two procedures to characterize crack arrest toughness have been proposed to the ASTM E24.03.04 Committee for possible adoption as a testing standard. One of the procedures, proposed by Battelle Columbus Laboratory (BCL), uses results from a dynamic computer code based on an energy balance criterion. This computer code is utilized to construct two reference curves which relate KID/KQ or KIDm with Δa/ao and V/co with Δa/ao. Here KID represents the plane-strain fast fracture toughness, KIDm the minimum value of plane-strain fast fracture toughness or plane-strain crack arrest toughness, KQ the initial stress intensity, V the crack velocity, co the bar wave velocity, Δa the crack jump distance, and ao the initial crack length.
With these two reference curves for a given specimen geometry and a knowledge of KQ, co, and Δa/ao, not only is the determination of the crack arrest toughness KIDm proposed but also the characterization of the stress-intensity factor and crack velocity relationship.
The authors have utilized a one-dimensional version of the computer code developed by BCL to examine the predicted crack behavior in Homalite 100 and have made comparisons with experimentally observed crack behavior. This paper discusses the following aspects:
1. Comparison of the predicted crack positions with experimentally observed positions for rectangular double cantilever beam (R-DCB) models.
2. Influence of the shape of the K versus crack velocity (˙a) relationship on the reference curves generated for the R-DCB geometry.
3. Examination and comparison of the BCL code-generated K-versus-˙a curve with the experimental curve for R-DCB and crack line loaded (CLL) compact specimens.
4. K levels and velocities predicted by the reference curves compared on a test-by-test basis with experimentally observed values.
Corrosion of Steel in Internally Sealed Concrete Beams Under Load
Authors: Flick LD , Lloyd JP 
Published: March 2009

The ability of internally sealed concrete to prevent corrosion in reinforcement under service conditions has not yet been established. To simulate service conditions, members containing flexural cracks under either static or repeated load and subjected to a period of flushing with fresh water were considered. Corrosion of the reinforcement was induced by daily applications of a 3 percent sodium chloride solution.
The results based on half-cell potentials showed that the corrosion of the reinforcement in internally sealed concrete exposed to salt water was dependent on the type of loading. Under static load, no corrosion of the steel occurred. Under repeated load, however, the corrosion of the steel in internally sealed beams and in beams of conventional concrete occurred at the same time. This indicates that internally sealed concrete may offer only limited protection for members subjected to repeated loads. The lack of correlation between half-cell potentials and rate of corrosion suggests that further research in this area is appropriate.
An Engineering Model for Assessing Load Sequencing Effects
Authors: Wozumi JT , Spamer T , Lambert GE 
Published: March 2009

An engineering model has been developed to assess the impact of load spectrum variables on fatigue crack growth in metal structures. The model is based on the effective stress concept of Willenborg et al and Gallagher et al, and has been extended to accommodate retardation/acceleration phenomena peculiar to transport spectra. Development was accomplished by consideration of basic principles and previously reported results of simple overload/underload spectrum testing. The model does not rely on additional empirical parameters except material constant amplitude crack-growth rates. Formulation is such that flight-by-flight crack growth may be assessed without recourse to cycle-by-cycle integration.
Predictive accuracy of the model was compared with the results of crack propagation testing conducted on 28 center-cracked 7075 and 2024 aluminum specimens subjected to transport wing and fin load spectra. Mission parameter variables investigated in this testing were: altitude, gross weight, flight duration, speed, and touch-and-go landings. Use of the model produced improved accuracy over that exhibited by other models currently in use in the industry. The capability of the model to accurately predict acceleration effects is considered unique.