bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Aquatic Toxicity of the Sensory Irritant and Riot Control Agent Dibenz(b,f)-1,4-Oxazepine (CR)
Authors: Johnson DW , Haley MV , Landis WG 
Published: March 2009

The aquatic toxicity of dibenz(b,f)-1,4-oxazepine (CR) was examined using organisms from three trophic levels. The compound is a peripheral sensory irritant which produces an immediate irritation of the eyes, nose, mouth, skin, and respiratory tract in man. The compound is comprised of a double benzene ring with a shared oxygen molecule and a doublebonded carbon, nitrogen group. The intended use of the compound is for the control of civil disturbances. Acute bioassays were performed using Ankistrodesmus falcatus, Daphnia magna, and Pimephales promelas. A 21-day static renewal test was performed using D. magna.
A 24-h EC50 of 1.48 mg/L and 48-h EC50 of 0.94 mg/L were calculated for daphnids. Significant differences in reproductive output and body length were observed at 0.50 mg/L using ANOVA in the 21-day chronic assay with D. magna. The 96-h algal growth inhibition test yielded an IC50 in the range of 1.95 to 3.55 mg/L. An LC50 of 2.6 to 2.8 mg/L was determined for the fish. An enhancement compared to controls in reproductive output was observed for both the algae and daphnia at low concentrations of CR. Dose response curves and comparisons of linear and exponential regressions are presented for several of the toxicity tests.
Use of Hazard Models in Evaluating the Effect of Exposure Duration on the Acute Toxicity of Three Pesticides
Authors: Moore DW , Schluchter MD , Scott GI 
Published: March 2009

Renewal toxicity tests (96 h) were conducted with the emulsifiable concentrates of three pesticides: azinphosmethyl, endosulfan, and fenvalerate. A second test design, which incorporated a 6-h period of exposure followed by 90 h of observation, was also conducted on these three pesticides.
Toxicity results from the two test types were then compared using different hazard models to test a series of null hypotheses. These comparisons indicated: (1) while the effect of concentration was constant across time, hazard changed for each of the test types; and (2) when the effect of concentration was the same for the initial periods of exposure (6 and 24 h) in the two test designs, the average hazard was significantly lower for 6 h of exposure than for 24 h.
This study may have significant implications for relating results from laboratory toxicity tests to mortality among organisms exposed in situ. The 6-h exposure test design provides information on delayed effects due to short-term exposures, while hazard analysis can be used to estimate the underlying time/concentration relationship from standard laboratory toxicity test data.
The Response of Diploid and Polyploid Rainbow Trout Cells Following Exposure to Genotoxic Compounds
Authors: Powell DB , Kocan RM 
Published: March 2009

Polyploid cells have been associated with malignant neoplasms in many animal species. Recent advances in the genetic engineering of aquatic vertebrates have made it possible to produce healthy rainbow trout (Oncorhynchus mykiss, formerly Salmo gairdneri) that are completely triploid (3n) or tetraploid (4n). The objectives of this study were to compare the effects of direct- and indirect-acting carcinogens on DNA repair and measure the relative binding of benzo[a]pyrene (B(a)P) to DNA in diploid and polyploid cells.
The level of DNA repair was measured in diploid and polyploid cells following an in vitro exposure to the direct-acting carcinogen N-methyl-N′-nitro-N-nitrosoguanidine (MNNG) or the indirect-acting carcinogen B(a)P. A DNA repair assay was used to compare the effects of MNNG and B(a)P on nucleated erythrocytes and hepatocytes.
Diploid and polyploid hepatocytes responded more strongly to MNNG than to B(a)P. DNA repair activity per haploid genome in polyploid fish hepatocytes was found to be greater than in diploid hepatocytes. Tetraploid cells consistently exhibited slightly more than twice the unscheduled DNA synthesis of the diploid cells. Rainbow trout erythrocytes were completely refractory to MNNG and B(a)P in the DNA repair assay.
The 32P-postlabeling assay, which measures DNA-bound compounds, indicated that at least five distinct DNA adducts are formed in rainbow trout liver cells following exposure to B(a)P. Diploid and tetraploid cells were found to contain significant differences in the relative number of specific adducts. No adducts were detected in the DMSO solvent controls.
Stress Proteins: Their Detection and Uses in Biomonitoring
Authors: Bradley BP 
Published: March 2009

The synthesis of stress proteins is induced by a wide variety of stressors and occurs in virtually every organism. Which proteins are synthesized depends on the stressor, and the amount of protein synthesized seems to depend on the level of stress.
Stress proteins can be detected quite easily autoradiographically or immunologically. A field immunoassay is feasible, allowing early warning of environmental problems as well as routine in situ monitoring. More sophisticated laboratory assays are also available, combining gel electrophoresis, autoradiography, immunoassays, and densitometry to confirm the field assessment and perhaps to suggest the physical or chemical stressor or stressors causing the problem.
The tests can be done on live, fresh, or preserved specimens. Assaying preserved specimens allows samples from different areas and times to be tested simultaneously.
The Use and Preparation of Curtain Wall Structural Design Drawings
Authors: Tawresey JG 
Published: March 2009

The concept of curtain wall structural design drawings is introduced. What are structural design drawings? How are they used and how are they prepared? These questions are discussed.
Curtain wall structural design drawings apply to either the design-then-bid or the bidder design construction format. They are analogous to the structural design drawings for a building structural frame and can be used for design team review and building department approvals.
The structural engineer's involvement in curtain wall design goes beyond conformance with prescription in the form of codes, standards, or specifications. There are few curtain wall prescriptions. Instead, the involvement relies on hands-on experience with the materials, judgment, customized testing, and analysis. The results of these efforts must be clearly communicated to the rest of the design team, and the curtain wall structural design drawing is a method to accomplish this task.
Innovations in Structural Sealant Glazing
Authors: Francis GV 
Published: March 2009

Structural silicone glazing—sometimes called flush glazing, stopless glazing, or just structural glazing—is a method of fixing glass to its supporting framework by an adhesive. This fixing method results in a smooth, uninterrupted surface of glass, which significantly improves the appearance of glass walls.
Use of the method has grown considerably since it was introduced in the early 1970s. Currently, nearly 30% of all commercial glazing in the United States is fixed in place using silicone on at least two edges of the glass.
Many people, however, are concerned about the safety aspects of the method. The industry has responded with improved materials, improved quality control procedures, and improved designs.
One of the most recently designed systems which addresses the safety issue uses a special insulating glass unit with a recessed channel around all four edges of the lite. The recess is then used to hook or clip the unit to the supporting mullion. The installation then gives the appearance of structural silicone glazing without relying entirely upon a silicone tensile bead.
The evolution and growth of structural sealant glazing, safety aspects, and the design, testing, and safety of the new method are presented.
Insulated Concrete Sandwich Walls
Authors: Sauter JE 
Published: March 2009

Durability, fire resistance, relatively low cost, and availability makes concrete a natural choice for wall construction. The insulating properties of concrete, however, greatly reduce its effectiveness. Concrete sandwich panels were developed in response to the need for more efficient concrete wall systems.
The first forms of sandwich walls used steel and/or concrete connections to hold two layers of concrete together with insulation sandwiched between. Steel and concrete traversing the insulation layer, however, can reduce the insulating value of a wall by 20 to 40% or more due to a phenomenon known as thermal bridging. A method for determining loss due to the thermal bridging has been developed by ASHRAE called the isothermal planes (series parallel) calculation method. A modern personal computer and spreadsheet can be used to easily perform these calculations.
Composite materials (reinforcing fibers and binding resins) developed for the aerospace industry have recently been adapted to take the place of steel and metal connections in concrete sandwich walls. The result is the ability to manufacture insulated concrete sandwich panels with no loss in thermal energy. The composite connections are stronger than steel, will not corrode, are flexible to withstand thermal cycling, and are cost competitive. Modern technology has provided concrete panel manufacturers with the ability to produce concrete panels that are almost 100% thermally efficient.
Glass Fiber Reinforced Concrete Cladding Panels
Authors: Knowles ES 
Published: March 2009

Glass fiber reinforced concrete (GFRC) panels are a lightweight cladding panel. They are used as facia panels for building structures. GFRC panels support their own vertical load and the vertical load from the glazing system.
The GFRC skin is reinforced (stiffened) by a steel stud frame. The stud frame is attached to the GFRC skin by means of flex anchors.
The gravity load of the GFRC skin is transferred to the stud frame by two methods: (1) flex anchors only and (2) gravity anchors in addition to flex anchors. The stud frame is attached to the structure, and the loads of the panel are carried through the stud frame to the panel connection points on the structure.
Deformation and Failure of Longitudinally Loaded Brittle-Matrix Composites
Authors: Lee J-W , Daniel IM 
Published: March 2009

A modified shear lag analysis is proposed for a unidirectional brittle-matrix composite under longitudinal tensile loading. It is assumed that the matrix, having a lower ultimate strain than the fiber, fails by transverse cracking. The analysis was conducted for a cylindrical element of matrix with a single fiber with various boundary conditions. Closed form solutions were obtained for stress distributions in the matrix and fiber as a function of applied stress and constituent properties in each case. In addition, the matrix crack density, debonded length, and reduced axial stiffness of the damaged model of two matrix cracks were obtained in closed form as a function of applied stress and constituent properties. The shear lag parameter is only a function of geometry and shear moduli of the constituents. The basic assumptions used in the analysis are that the shear stress in the fiber varies linearly and in the matrix varies according to an inverse function of a second-degree polynomial in the radial direction. The analysis can take into account residual stresses in the material.
The predicted stress-strain and stress versus matrix crack density curves were compared with experimental results for a silicon carbide/glass ceramic (SiC/CAS) composite subjected to monotonic loading. The predictions in general are in good qualitative agreement with experimental results. In particular, the saturation crack density measured is very close to the predicted value.
Analysis and Test Techniques for Composite Structures Subjected to Out-of-Plane Loads
Authors: Paul PC , Saff CR , Sanger KB , Mahler MA , Kan H-P , Kautz EF 
Published: March 2009

The ability to predict stresses and failures caused by out-of-plane loads has gained importance as airframe manufacturers begin to use integral (co-cured or bonded) composite structures to minimize weight and maximize performance. Rapid and accurate analysis methods are needed to reduce the amount of testing required to ensure confidence in integral composite structures. Recently, simple two-dimensional analysis methods were developed to predict the out-of-plane failure strengths of composite airframe structures. These analyses were primarily derived to address induced stresses in laminate corner radii, direct stresses as a result of fuel pressure loads, induced stresses as a result of panel buckling, and induced stresses as a result of stiffener runouts or other load path changes.
The development and verification of analyses for out-of-plane failures have shown the need for out-of-plane material properties and strength allowables that are not traditionally determined for composite laminates. Accurate stress and failure predictions depend heavily on these experimentally determined values. The test methods and experience gained in this program indicate the need for new techniques to determine the interlaminar properties required for accurate stress and failure predictions. Test techniques are suggested for determining some of the values necessary for these predictions.
Analysis and Testing of a Composite Sandwich Shell Horizontal Tail
Authors: Sherrouse MA , McWhorter JC 
Published: March 2009

This paper presents the preliminary results of an investigation into the use of a sandwich shell without spars or ribs as a horizontal tail on a light general aviation aircraft. The primary motivations for designing such a structure are simplicity, ease of construction, and the reduction of fasteners.
The structure investigated consisted of two symmetric, quasi-isotropic sandwich skins with four plies of graphite-epoxy unidirectional prepreg per face and 10-mm honeycomb core laid up in an airfoil-shaped mold and cured at 120°C. The two halves were joined by adhesive to form a tapered cantilevered beam with airfoil cross section truncated at the 56.7% chord line. Two internal ribs were installed at the fuselage contour near the center of the tail to provide attachment to a frame. Symmetric point loads were applied to produce varying amounts of torsion and bending, and the results were compared with analysis from a NASTRAN model using elements with composite material properties. The structure was loaded to failure, and the results were compared with analysis from a NASTRAN buckling routine.
A structurally intact portion of the failed test piece was modified to create one half of a fullsize forward-swept tail. Again, experimental results from various bending and torsion loads were compared with analysis from a comparable NASTRAN model.
Chordwise and spanwise strain plots indicated that the sandwich skins carry the bending loads, whereas the reinforced areas at the leading and trailing edges act as shear webs. Good correlation between the experimental strains and NASTRAN analysis was obtained.
Image Enhancement Techniques for Ultrasonic NDE Applications
Authors: Steiner KV 
Published: March 2009

Ultrasonic nondestructive evaluation (NDE) methods are reliable in the inspection and certification of composite structures. Complex structures are scanned by sophisticated automated multi-axis robotic systems. The acquired data are processed to generate images based on peak-amplitude or time-of-flight data. Digitizing of the ultrasonic information has opened the door to powerful computer graphics image enhancement techniques.
Image enhancement techniques can be applied such that critical information is highlighted and defects detected in the structure are classified. Used properly, image enhancement of digitized data dramatically improves the interpretability of ultrasonic information. A wide variety of image enhancement techniques, applicable in particular to ultrasonic NDE, are discussed. In addition, a new method of interpreting ultrasonic data by working from digitized full-volume waveform information is presented. This work, combined with statistical analysis methods, enables the operator to perform complete post-scan evaluation.
Stress Field Sensitivity of a Composite Patch Repair as a Result of Varying Patch Thickness
Authors: Siener MP 
Published: March 2009

The desired method for repair of composite airframe structures is by joining with an adhesive(-like) material. The available choices of structurally efficient joint configurations are limited. Most of the commonly used joint configurations would result in repairs that would be either impractical, because of the long adherend overlap lengths required to sustain the design load, or unsafe, because a shortened lap length would limit the load-carrying capability of the joint. Single lap joint configurations based on a variety of patch material thicknesses and stiffnesses are investigated for elastic response and strength capability. The section stiffness of the patch material is kept constant in the direction of the first principal stress, as the number of plies is decreased. The average modulus of the patch adherend is increased by reorienting the plies in the laminate. This is done to demonstrate the possibility of increasing the average joint failure shear stress and the accompanying load transfer efficiency by increasing the stiffness of the adherends. Stress analyses of these configurations are carried out and compared to the results from testing the described configurations.
Experimental data show that it may be necessary to incorporate the nonlinear adhesive behavior into the model to account for the extensional response of the adherends. Also, it may be necessary to model each composite ply to predict the extent of incompatibility of the adhesive bondline and the adjacent composite material. The data also demonstrate that the failure of a composite joint depends on the strength of bondline-contacting interfacial plies, as well as the usual factors considered when estimating joint strength.
Characterizing the Fire Safety of Liquid Pesticide Formulations by Using ASTM D56 Tag Closed Cup Flash Point Method
Authors: Namnath JS 
Published: March 2009

Building codes in the United States use the letter and intent of model codes issued by the National Fire Protection Association (NFPA). The most recent NFPA codes restrict warehousing of flammable and combustible liquids contained in plastic. To meet these new requirements, formulations are developed to have a higher flash point, incorporate water as a a major ingredient, or are converted to a non-liquid form.
NFPA flammability classification for liquid pesticides is largely based on results of ASTM D56 Tag Closed Cup Flash Point Method.
This study used ASTM D56 to determine flash points of liquid pesticide formulations of varying composition and water content.
In mixtures of combustible and flammable aromatic solvents the flash points were unaffected by relatively high fractions of flammable aromatic content. In other systems where the formulation had considerable water content and a small amount of aromatic solvent the flash points were found to be close to that of the solvent.
This study concludes flash points of complex formulations cannot be assumed to be that of the lowest flash component. Systems must be tested individually for accurate results.
Adjuvants to Reduce Drift from Handgun Spray Applications
Authors: Salyani M , Cromwell RP 
Published: March 2009

The off-target drift deposits from handgun applications of two spray mixtures (one with an invert emulsion oil and one with a polymeric adjuvant) were compared to that of water, all containing a fluorescent dye tracer. Drift deposit samplers consisting of mylar sheets and air sampler filters were positioned at several locations downwind and around the line of spray application. Weather data were recorded by a weather station and the amounts of the tracer dye deposit on the targets were measured with a fluorometer.
Spray mixtures containing the adjuvants produced lower drift deposits, on both mylar sheets and filter papers, as compared to water only sprays. The use of invert emulsion oil (Visko-Rhap) resulted in the lowest drift deposits from handgun applications.
Evaluation of Fumed-Silica Insulation for a Thermal Conductivity Standard Reference Material
Authors: Rennex BG , Somers TA , Faison TK , Zarr RR 
Published: March 2009

Standard Reference Materials (SRMs) used for thermal conductivity measurements are required by industry, academic, and government laboratories for calibrating heat-flux-meter apparatus or checking the accuracy of guarded-hot-plate apparatus. New thermal conductivity SRMs are sought to improve the accuracy and extend the operational range of these apparatus. An advisory panel recommended the development of a low thermal conductivity SRM having approximately the same thermal conductivity as blown fluorocarbon foams, suitable for a temperature range of -175 to 900°C. Fumed-silica insulation was recommended by the advisory panel as the most suitable material.
The National Bureau of Standards (NBS) examined four lots of fumed-silica insulation and recommended one candidate for further development as a low thermal conductivity SRM. The four lots of fumed-silica insulation were examined for their relative handleability, material uniformity, variability of thermal conductivity measurements, and effect of heat treatment on the measured thermal conductivity of the materials. Thermal conductivity measurements were conducted using the NBS 1-m Guarded Hot Plate for each lot of fumed-silica insulation at a mean specimen temperature of 24°C. Analysis of the thermal conductivity data was performed using the NBS statistical analysis program, Dataplot.
Radiant Heat Transfer in Extremely Low Density Fibrous Assemblies
Authors: Dent RW , Skelton J , Donovan JG 
Published: March 2009

In very low density insulating assemblies, heat transfer occurs mainly by gas phase conduction, by convention, and by radiation. Many attempts have been made to analyze the parameters that control the radiant component of this heat transfer using electromagnetic theory based on the Maxwell equations. Extensive solutions are available in the literature for spheres but few results have been calculated for cylinders (which would model fibrous insulations), although the relevant equations have been given by Van de Hulst and by Larkin and Churchill. Larkin and Churchill give appropriate values for “real” refractive indices only, with zero absorption.
We have now obtained complete “complex” solutions as functions of fiber diameter and the fiber optical properties of refractive index and absorption coefficient (or dielectric constant). These solutions allow a full understanding of the roles of scattering and absorption in radiant energy transfer and show how these can be optimized for various materials as a function of wave-length (or temperature).
Once the radiant heat transfer is minimized for single isolated cylinders, we consider how this translates to a low density assembly of many such cylinders or fibers. The results show that radiant heat transfer can be minimized by the selection of an optimum fiber diameter and that this optimum differs for each material and for different absorption coefficients (as these affect the real and imaginary parts of the refractive index which determine the heat transfer).