bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Calibration Procedural System and Facility for Gas Turbine Engine Exhaust Emission Analysis
Authors: Elwood JH 
Published: March 2009

This paper is directed toward those individuals and organizations who, in the process of being regulated, are, or have been, required to develop their own standard reference materials, to establish the analytical procedures necessary to develop and maintain these materials, and to evolve a calibration methodology for using these standard materials in day-to-day operations, as well as for compliance testing.
In the Federal Register, (Vol. 38, No. 136, Part II, 17 July 1973) the Environmental Protection Agency (EPA) promulgated “Emissions Standards and Test Procedures for Aircraft.” Maximum allowable emission levels were established for smoke, carbon monoxide, hydrocarbons, and oxides of nitrogen; and, in addition, criteria were established for the measurement of these constituents. Requirements were also set for the measurement of carbon dioxide to be used in determining the representativeness of the sample. At that time, only a few selected standard reference materials, developed for the automotive industry, were available. These were three concentrations of carbon dioxide in nitrogen and five concentrations of propane in air, all certified to ±1 percent over a 95 percent confidence interval. The EPA required that all calibration gases would be known to ±2 percent without specification of the confidence interval. There was no suggestion as to a source of these relatively high accuracy gases, how to guarantee the accuracy of assay, or how they were to be maintained, monitored, and used. Generally poor experience with gas vendor's abilities to consistently supply gases within 2 percent of the certified analysis, and the demonstrated instability of some mixtures in the cylinder led, in part, to the decision to develop a standard reference materials laboratory in support of our emissions measurement technology programs. This standards laboratory was charged with :
1. Providing a bank of standard reference gases for use in all emissions measurement technology programs at Pratt and Whitney Aircraft.
2. Where analytical procedures for making high accuracy determinations of gas concentrations were lacking, to develop this capability.
3. Develop procedural systems necessary to make this reference bank of standards available for day-to-day instrumentation calibration, and 30-day detailed calibrations as required by the EPA.
4. Determine, insofar as practicable, our ability to perform analyses and assign concentration levels in comparison with the rest of the industry.
5. As National Bureau of Standards standard reference materials become available, to adopt these standards and phase them into our program.
These goals have been met in essentially all respects. In addition, it has been determined that the practically achievable precision and accuracy of measurement is significantly different from that implied by the EPA, and it is highly unlikely that their high accuracy requirements can be met.
Problems with Zero Gases for Ultra-Low Level Measurements of Air Pollutants
Authors: Scott WE , Marrin JT 
Published: March 2009

The replacement of wet-chemical methods of measuring air pollutants by more sophisticated instruments has introduced a number of new problems. Most of the new analytical instruments do not give absolute results. Instead, their measurements are relative to a reference standard containing a “known” concentration of the pollutant of interest and to a “zero” standard containing neither the pollutant of interest nor interfering components. As the attempt is made to measure pollutants at very low levels, it becomes more difficult not only to produce reference standards, but also equally difficult to establish the zero level.
The specific requirements for ultra-pure zero gases, including carrier gases employed in Chromatographic measurements, are illustrated for many instruments in use today. Problems in the handling of zero gases are discussed. Results of tests demonstrate the ease of contamination of zero gases by regulators, sample lines, syringes, etc. Solutions to many of these handling problems are presented.
The Importance of Sequential Assessment in Test Programs for Estimating Hazard to Aquatic Life
Authors: Duthie JR 
Published: March 2009

The qualification process for a new chemical should include not only appropriate toxicity testing but supportive evaluations which allow an assessment of potential risk to aquatic life. Since materials differ not only in toxicological effect but also in other properties that can affect their ecological impact, each material should be considered individually, and any tendency to apply a rigid standard test program to all should be resisted. Guidelines are provided to develop testing programs which will provide a sound basis for hazard assessment without squandering limited scientific resources.
Review and assessment of data on a sequential basis are necessary to focus effort on the most appropriate kinds of tests. Based on expected usage and disposal patterns, it is important to estimate the maximum concentrations that are likely to occur in the environment and their critical locations. When chemical or biological tests have indicated that a material will not be persistent, the use of shorter term toxicity tests on sensitive life stages may be substituted for total life-cycle tests. Similarly, consideration of chemical and physical properties may provide guidance on the need or priority for bioconcentration testing.
Review points are identified where a decision to either abandon or utilize a test material should be considered rather than continuing a fixed pattern of testing that merely postpones a difficult judgment.
A New Capacitor Fluid—A Case Study in Product Stewardship
Authors: Branson DR 
Published: March 2009

Product stewardship is a commitment to exercising responsible care during the manufacturing, use, and ultimate disposal of chemical products. An important part of product stewardship is the generation of an adequate data base to assess the potential hazards of a new product. A new capacitor fluid (Dow's XFS-4169L) is a working example of product stewardship. Electrically, the fluid has been found to perform as well as or better than capacitor-grade polychlorinated biphenyl (PCB) in capacitors. Assessment of its health and environmental acceptability was based on the composite interpretation of movement, stability, bioconcentration, and toxicity data.The use pattern, sediment binding, and recommended disposal suggest that only small amounts of the new capacitor fluid will enter the aquatic environment. The routes for leaving the aquatic environment—biodegradation and volatilization—allow only very low concentrations of the capacitor fluid to remain in water. The bioconcentration potential of the fluid is low enough so that residue levels in fish are not critical to the health of the fish or animal consumers, and its toxicity to aquatic organisms is similar to that of a large group of commodity chemicals and less than PCB's.
Bioassays with a Natural Assemblage of Benthic Macroinvertebrates
Authors: Burks SL , Wilhm JL 
Published: March 2009

A new bioassay method for determining the effects of environmental contaminants on populations of benthic macroinvertebrates is described. Colonized Hester-Dendy samplers were transported from a natural stream to artificial streams and exposed to industrial wastewater. Species diversity, number of taxa, and density of the aquatic organisms were measured before and after selected time intervals of exposure. A 30 and a 32-day continuous-flow exposure test with the benthic macroinvertebrates showed that activated sludge treated petroleum refinery wastewater caused a greater decrease in species diversity than the sequential activated sludge-dual media-activated carbon treated effluent. The effect upon number of taxa and mean density of individuals was even greater.
This procedure permitted exposure of several species of aquatic invertebrates to the test solution and thus measured the effect upon pollution-sensitive and tolerant organisms.
Uptake, Clearance, and Bioconcentration of 14C-Sec-Butyl-4-Chlorodiphenyl Oxide in Rainbow Trout
Authors: Blanchard FA , Takahashi IT , Alexander HC , Bartlett EA 
Published: March 2009

Steady state bioconcentration factors for sec-butyl-4-chlorodiphenyl oxide in rainbow trout muscle were calculated using a simple two-compartment model from radioassay data of concentrations of 14C in fish and water during an uptake and clearance (depuration) experiment. There was a relatively rapid removal with one half of the material cleared in 30 to 40 h.
Average Exposure Concentration, ppbUptake Rate, k1, ppb/ppb/hClearance Rate, k2, h−1Bioconcentration FactorClearance Half Time, hTime to 90% of Steady State, h3.626.1 ± 1.00.021 ± 0.004292 ± 7533 ± 7111 ± 220.345.3 ± 0.50.016 ± 0.002336 ± 5244 ± 5146 ± 18
A partition coefficient (octanol/water) for sec-butyl-4-chlorodiphenyl oxide of 16000 ± 4900 was measured. The regression equation relating the partition coefficient to bioconcentration factor in trout muscle predicts a bioconcentration factor of 100 to 500, in agreement with the calculated values of 292 and 336.
The two-compartment model used for analysis of the data does not distinguish between 14C activity in the form of sec-butyl-4-chlorodiphenyl oxide from that in the form of metabolic products. The reported bioconcentration factor is an overall number encompassing both the compound and its metabolites. Thin-layer chromatography analysis of tissue extracts showed polar metabolites were formed during the experiment. The calculated bioconcentration factors are somewhat larger than they would be if put on a pure compound basis. However, we believe that the reported bioconcentration factors are valid, since there is good agreement between the 14C-derived muscle bioconcentration factors and the bioconcentration factor derived from the partition coefficient equation.
A Model System to Study the Desorption and Biological Availability of PCB in Hydrosoils
Authors: Halter MT , Johnson HE 
Published: March 2009

Model aquatic systems incorporating hydrosoil, water, and fish components were used to measure the dynamics of Aroclor 1254 [polychlorinated biphenyl (PCB)] under both flowing and static water conditions.
PCB desorption from hydrosoils was consistent with adsorption-desorption theory. Under static conditions, hydrosoil PCB concentrations from 10 to 500 µg/g produced equilibrium levels of 0.13 to 7.60 µg/litre PCB in water. In continuous flow tests, equilibrium PCB levels in water ranged from 0.11 to 0.54 µg/litre for hydrosoil concentrations of 100 to 500 µg/g PCB. Equilibrium PCB concentrations in water could be predicted under both static and continuous flow conditions with the distribution coefficient equation. Desorption favored the lower-chlorinated, more water-soluble components of Aroclor 1254.
Fathead minnows allowed direct contact with PCB-contaminated hydrosoils accumulated PCB residues at six times the rates of those screened from direct exposure to sediments. Fish selectively bioaccumulated the higher chlorinated components of Aroclor 1254.
Evaluation of the Significance of Waterway Sediment-Associated Contaminants on Water Quality at the Dredged Material Disposal Site
Authors: Lee GF , Mariani GM 
Published: March 2009

During the past few years, considerable interest has developed concerning the significance of chemical contaminants associated with dredged sediments. Research has been done on the factors influencing the release of contaminants from waterway sediments and the toxicity of these sediments to various forms of aquatic life. This study has shown that the only two compounds which are released in potentially significant amounts to affect water quality at the disposal site are manganese and ammonia. The other compounds studied including heavy metals, chlorinated hydrocarbon pesticides, polychlorinated biphenyls (PCBs), and aquatic plant nutrients are either not released, released in insignificant amounts, or taken up as a result of mixing the sediments with the overlying waters under conditions which simulate typical dredging and dredged material disposal.
Bioassays conducted of the elutriates of the sediments with the sediments present show that, in general, large concentrations of contaminants can be present in dredged sediments which would have little or no effect on water quality at an in-water disposal site. These results show that the bulk chemical criteria that have been used frequently by pollution control agencies to establish the method of dredged material disposal are not a technically valid approach for determining the significance of contaminants associated with natural water particulate matter. In fact, in some instances, the methods of dredged material disposal which have been adopted because of excessive concentrations of contaminants based on bulk chemical criteria may have been more detrimental to environmental quality than the previously used methods of dredged material disposal.
Realism in Fatigue Testing: The Effect of Flight-by-Flight Thermal and Random Load Histories on Composite Bonded Joints
Authors: Wilkins DJ , Wolff RV , Shinozuka M , Cox EF 
Published: March 2009

Current military specifications call for increased realism in fatigue testing. Criteria are discussed which recognize those portions of a spectrum that should be random and those that should be deterministic.
This paper documents a research program which included spectrum development, test facility setup, and a limited test series. The spectrum was a flight-by-flight random load history including realistic mission temperature exposures. The test facility utilized a small digital computer for closed-loop control of load and temperature.
Results of tests on three sets of five boron-epoxy-to-titanium bonded joints are discussed, and the effects of temperature exposure and time acceleration are investigated.
Microstructure Approach to Property Optimization in Wrought Superalloys
Authors: Muzyka DR , Maniar GN 
Published: March 2009

The effects of structure control available from the precipitating phases in wrought superalloys were demonstrated in a recent review. It was shown that criteria for selection of superalloys should be reviewed periodically to establish that they reflect the state of the art. For example, expensive materials may have been specified where lower cost alloys could do a job equally well. This is especially true for superalloys in applications where properties up to about 1200°F are critical.
This paper reviews some results of the continuing study by superalloy metallurgists to reveal means of “retrograding” elevated temperature requirements to lower cost compositions that, combined with proper processing, will meet property requirements. It is shown that microstructure studies, combined with knowledge of phase relationships, prove to be an invaluable tool. Recent examples of improved hot-work behavior, heat-treat response, and property development are reviewed. Effects of thermomechanical processing are also discussed.
Effects of Rest Time on Fatigue Crack Retardation and Observations of Crack Closure
Authors: Sharpe WN , Corbly DM , Grandt AF 
Published: March 2009

Fatigue cracks grown in compact tension specimens of 2024-T851 aluminum at ΔK = 6.93 MN/m3/2 (R =0.1) were subjected to single-peak overloads of 17.31 MN/m3/2. After the overload, the specimens were held at zero load for periods of 3 min, 1 h, and 20 or more hours before recycling at ΔK = 6.93 MN/m3/2. Increasing the rest time had the effect of slightly reducing the crack retardation as measured on the specimen surface.
The load at which the fatigue crack faces fully separate was measured on the specimen surface by laser interferometric techniques and in the specimen interior by through-transmission ultrasonic methods. Crack opening loads measured on the specimen surface were found to increase with application of an overload and then decrease to the original value when the specimen was allowed to rest at zero load, while opening loads measured through the sample by the ultrasonic method did not vary significantly with peak loads or rest times. Varying specimen thickness between 0.64 and 2.54 cm had little effect on surface measured retardation or opening loads. The relationship between applied load and crack surface displacement as measured by ultrasonics varied significantly with specimen thickness.
Mathematical Modeling of Crack Growth Interaction Effects
Authors: Bell PD , Wolfman A 
Published: March 2009

A combined analytical and experimental program was performed to obtain additional insight into the growth of cracks subjected to simple variable-amplitude loading. The experimental results were used to examine methods of mathematically modeling crack propagation behavior to enhance predictive capability for arbitrary spectrum loading.
The mathematical modeling consisted, primarily, of using the crack closure concept to correlate predicted crack propagation behavior with observed behavior for various simple loading spectra. Two analytical schemes were developed, one of which calculated the crack opening load based on residual forces acting on the crack surface, and another where empirical relationships between loading sequences and crack opening behavior were utilized. Difficulties with the Residual Force Model in correctly representing some of the experimentally observed crack opening and closing effects led to emphasizing the development of the more empirical Crack Closure Model.
The test program encompassed constant-amplitude tension loads, single and multiple tensile overloads, compression spikes, and simplified variable-amplitude load sequences applied to 2219-T851 aluminum and Ti-6Al-4V annealed titanium alloy specimens. Detailed crack-growth and crack closure measurements were obtained. These measurements were used to quantify crack closure behavior as a function of stress ratio, including negative values, and various loading sequences.
Spectrum Fatigue Crack Growth in Lugs
Authors: Impellizzeri LF , Rich DL 
Published: March 2009

Analytical and experimental investigations were conducted to determine the crack growth behavior in lug joints subjected to a randomized flight-by flight spectrum. Specific objectives were to evaluate capabilities for analyzing spectrum crack growth in lugs and to assess the effects on crack growth of KIc and cold working the material surrounding the lug holes. Stress intensity solutions were developed for cracks radiating from lug holes using Bueckner's weight function approach for various stress distributions surrounding the lug hole. The stress distributions were determined using an elastic/plastic finite element analysis. Included in these analyses were residual stress distributions following either large lug loads or mandrel hole enlargement. Spectrum crack growth calculations were made using the resulting stress intensity values and the Wheeler retardation crack growth model.
Lug specimens were fabricated from two heats of 6Al-4V mill annealed titanium representative of material having low and high fracture toughness levels. Basic mechanical properties including ultimate and yield strength, percent elongation, and reduction in area and fracture characteristics, including KIc and constant-amplitude crack growth rates, were determined for each heat of material. EDM cuts in the lug specimens were used as points of stress concentration where precracks were developed by low-level constant-amplitude fatigue loading. The lug holes of selected specimens were cold worked to determine the effect of compressive residual stresses on the crack growth rate. Plots of crack growth versus spectrum hours were obtained for each specimen by post-failure examination of the fracture surfaces using the scanning electron microscope.
Report on the Paper Workshop
Authors: Arnold EW 
Published: March 2009

The percentage recycling of paper in the United States has recently increased, reversing the previous downward trend. Old corrugated containers appear to be recyclable at increasing rates without major new technology or incentives needed. Old newspapers are readily recycled, but new cleaning and contaminant control technology are needed to allow their use in the applications where the largest additional consumption would be available. Mixed waste paper represents the greatest challenge for increased recycling as there are substantial technical and economic factors to be resolved if its consumption is to be markedly increased.
Recommendations included the preparation of information kits for aiding municipal collection of segregated wastepaper, for assembling background information on the recycling technology of selected grades, and an analysis of the impact of various possible incentive programs.
Applications of Neutron Radiography to Histopathology
Authors: Boyne PJ , Whittemore WL 
Published: March 2009

This paper describes a four-year study of the application of neutron radiography to histopathology using an approach directed toward improvement in histologic sectioning, staining and tissue preparation techniques, and refinement in the application of neutron radiography in three areas: 1. characterization of normal tissues of the facial bones and jaws, 2. diagnosis of intraosseous tumors and a delineation of the invasion of the tumor into the surrounding bone, and 3. the study of metallic semiburied implants attached to bone of the jaws.
It was found to be possible, through the application of these techniques, to determine the presence of intraosseous tumor tissues and to determine the exact extension of the tumor tissue along the marrow vascular spaces and the neurovascular bundles of the bone. Additionally, it was found to be possible to delineate various normal anatomic structures of the facial bones and surrounding soft tissue, and to study the interface between semiburied metals and the surrounding bone and surrounding soft tissue.
It is felt that neutron radiography will provide a significant diagnostic tool in research and in surgical pathology as an adjunct to the usual microscopic method of tissue examination, and additionally in the study of osseous-soft tissue interface with various types of metal implants.
Testing for Moisture Content in Foods by Neutron Gaging
Authors: Helf S 
Published: March 2009

Neutron gaging was applied to the testing for moisture content in bulk powdered foods and in canned Army field rations. The technique is based on the moderation or thermalization of fast neutrons by hydrogenous matter and the measurement of thermal neutron intensity as a function of moisture content. A small californium-252 capsule, of approximate output 107 neutrons per second, was used as the source of fast neutrons.
It is concluded that a fast neutron moderation technique is feasible for the nondestructive measurement or control of moisture or both in near-dry bulk powdered foods. Samples must be measured under identical geometric conditions, that is, uniform bulk density and volume using a standard metal container or cell. For canned or otherwise prepackaged rations, measurement of moisture is interfered with by variations in fill weight among cans or packages of the same product. A gamma-ray attenuation gaging method proved to be of insufficient sensitivity to correct for fill weight variation and was further complicated by nonuniformity in can wall dimensions. Neutron gaging, however, appears to be quite useful for monitoring a standard packaged item for fill weight since the neutron signal is virtually unaffected by variations in container dimensions. The radiation dose imparted to a sample or package of food subjected to such a test is judged to pose no threat to humans from subsequent consumption of the food. An estimate is given for the cost range of a commercial neutron gage and of encapsulated radioisotopic neutron sources.