bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Transport Aircraft Wing Loads Spectrum Variation on Crack Growth
Authors: Abelkis PR 
Published: March 2009

The effect of spectrum loading variations on crack growth were evaluated analytically and experimentally using C-15, KC-10A, and DC-10 transport aircraft wing loads spectra and 7475, 2024, and 7075 aluminum alloys. A total of 134 spectrum variations were generated in the following categories: (1) baseline spectra; (2) mission mix; (3) sequence of missions; (4) individual flight length; (5) flight segments; (6) exceedances spectra; (7) design stress level or usage severity; (8) valley/peak coupling; (9) low-load truncation; (10) high infrequent loads; (11) clipping of large loads; (12) miscellaneous variations, including the effect of flight loads alleviation system; and (13) combined variations. Spectra were generated as random cycle-by-cycle, flight-by-flight loading sequences. Crack growth tests, with cracks starting as through-thickness or corner cracks on one side of a hole, were performed on 47 of these spectra.
Analysis to test correlation shows 40 percent or better accuracy 78 percent of the time. However, different crack growth models had to be used to match the three aircraft baseline spectra: linear (C-15 and DC-10) and modified generalized Willenborg (KC-10A). Crack growth due to spectrum loading, with respect to loads interaction effects, appears to be a function of retardation and acceleration phenomena. An analysis model, incorporating both of these phenomena, is needed to properly predict spectrum variation effects.
Largest effect on crack growth life due to spectrum variations, as measured in flight hours, was due to mission mix, flight length, design stress level or usage severity, high infrequent loads, load alleviation system, and a change from a wing type to a vertical tail type spectrum. Using spectra variations that could be expected in service, fleet-wide crack growth variations by factors in the neighborhood of 100 and 10 could be experienced, depending on whether a short-term or a long-term spectrum variation is considered.
Radiation Sources and Detectors
Authors: Polansky D 
Published: March 2009

Some characteristics of radiation sources, such as X-rays, electrons, protons, and neutrons used in the nondestructive testing of material, are presented. Detailed information on the quality of inspection possible with X-rays is also presented.
The different types of detectors such as ionization chambers and solid-state detectors are briefly reviewed, while a detailed presentation is made of the characteristics of film. The capability of the radiographic system as described in specifications is presented as the measuring base for competitive methods of image analysis in nondestructive test systems.
Real-Time Radiographic Imaging for Submerged-Arc Welded Pipe
Authors: Rudolph RG , Henry EB 
Published: March 2009

According to American Petroleum Institute (API) Standards 5L and 5LX, the longitudinal weld in submerged-arc-welded (SA-welded) pipe may be nondestructively inspected by either radiological or ultrasonic methods. Each method has particular merits for detection of the weld imperfections normally encountered; the ultrasonic method has high sensitivity to planar imperfections, and the radiographic method has high sensitivity to volumetric imperfections. Although both methods have proven capable of meeting customer requirements, recent specifications for pipelines in the Arctic and offshore require automatic ultrasonic inspection.
The trend toward ultrasonic inspection was anticipated; hence, there was sufficient lead time to study the effects that it would have on flaw discrimination and rejection rates and to develop an automatic system that could meet all current and anticipated requirements. This new inspection system combines ultrasonic and radiographic inspection units in a complementary manner, utilizing each to detect the type of weld imperfection to which each is most sensitive and without confirmation by the other. Thereby, the combined system will exceed the individual performance of either unit for the detection of weld imperfections.
To satisfy the design objectives for this new inspection system, the radiological portion was to be capable of displaying a consistent 2 percent 2T sensitivity image, equivalent to radiographic specifications. Accordingly, a reasearch effort was initiated to develop an improved fluoroscopic system design.
Analysis of the performance limitations for a wide variety of fluoroscopic system designs indicated that designs employing low-light-level television (TV) systems with direct X-ray to light conversion screens showed the best long-range potential for development. The concurrent development of scan-conversion equipment capable of storing and integrating TV images gave considerable impetus to this effort, and a new system design was proposed that would be capable of providing both improved real-time imaging and stored images and could meet the requirements of equivalent radiographic sensitivity.
This new fluoroscopic system design was developed through several prototypes. The final version, available through Inspection Technology, Inc., Twinsburg, Ohio, is now installed in two pipe mills for the inspection of SA-welds. These systems are used in conjunction with automatic ultrasonic inspection systems concurrently developed by U.S. Steel. They provide acceptable 2 percent 2T sensitivity, with additional features of automatic inspection data display, image integration on command, 35-mm film image recording, and correlated display of ultrasonic alarms on the TV monitor.
This paper describes the development of the fluoroscopic system, analyzes the critical system parameters, describes tests performed, and describes the results obtained.
Real-Time Digital Image Processing for Radiological Imaging
Authors: Mengers P 
Published: March 2009

Advances in semiconductor memory and microprocessor technology combined with significant cost reductions for these devices have made it technically feasible to develop high-speed, high-performance, stand-alone digital imaging equipment.
The paper describes the design and operation of a digital image processing unit that provides several significant image improvement capabilities especially important to radiological imaging.
Among these capabilities are noise averaging, image differencing or comparison, contrast transfer modification, spatial filtering, and edge enhancement. Most of these operations are performed at television rates in real time without resort to off-line processing in an associated computer. However, the units own random-access digital memory can be time-shared with an external central processing unit for additional processing through software.
Examples of application to X-ray and neutron radiography are presented, including processing of very-low-contrast imagery. The discussion includes also an analysis of the signal-to-noise ratio improvement that is attainable with equipment of this type.
Cylindrical-Scanning Transaxial Roentgen Tomography of High Temporal Resolution
Authors: Ritman EL , Robb RA , Harris LD , Kinsey JH , Gilbert BK , Smith KT , Wood EH 
Published: March 2009

A prototype multiple X-ray source computerized transaxial tomographic system called the Dynamic Spatial Reconstructor (DSR) is currently being fabricated. This system is to consist of 28 X-ray sources arranged in a semicircle with 28 corresponding image intensifier/image isocon imaging chains arranged along an opposing semicircle. This entire system will permit mathematical reconstruction imaging of a cylindrical three-dimensional volume 23 cm axially and 30-cm diameter transaxially. This entire volume can be scanned in various ways ranging from the high “temporal resolution” (10 ms repeated 60/s), spatial resolution [full width half maximum (FWHM) 6 mm axially and transaxially], and “density resolution” (10 percent of roentgen opacity of water) to longer scan durations (for example, 100 ms up to a maximum of 2 s) with associated increases in spatial or density resolution or both.
It is anticipated that in addition to providing much needed information about optimal scanning configuration needs and requirements for different biomedical questions, the DSR is expected to be particularly useful in quantitation of the dynamic structure, function, and perfusion of the heart, lungs, and other organs.
Residential Air Pollution Levels: Observation and Data Interpretation
Authors: Moschandreas DJ , Stark JWC , McFadden JE , Morse SS 
Published: March 2009

A program to characterize the air quality in the residential environment has been undertaken. The generation of the data base, the interpretation of the data, and the formulation and application of an indoor-outdoor numerical model will be discussed.
Pollutant concentrations are sampled in three indoor locations and one outdoor location. “Instantaneous” readings are obtained for carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO2), ozone O3, sulfur dioxide (SO2), total hydrocarbons (THC), methane (CH4), and carbon dioxide (CO2); 24-h averages are monitored for total suspended particulate (TSP) and respirable suspended particulate (RSP) matter, sulfates, nitrates, lead and organics; aldehydes are sampled on a 4-h basis. In addition, the meteorological conditions both indoors and outdoors are measured, and the air exchange rate of each residence is experimentally determined. Elemental analysis is performed by proton-induced X-ray emission (PIXE). Finally, the kilowatt hours for heating, cooking and alternate current; the furnace efficiency; structural specifications; and other energy parameters are measured. The objective of this project is to develop causal relationships between the energy conservation measures-indoor (residential) air pollution concentrations and health effects.
Data analysis shows that the national ambient standards have been violated in the indoor residential environment for two pollutants, ozone and nonmethane hydrocarbons. Additionally, the American Society for Heating, Refrigerating, and Air-Conditioning Engineers' (ASHRAE) recommended indoor air pollution standards are violated by the following pollutants: carbon dioxide, total suspended particulate matter, and aldehydes.
A numerical model relating indoor and outdoor air pollution levels has been developed for the project. The model has been validated with the large data base sampled in the field studies. A series of numerical simulations indicate that under certain conditions energy conserving measures will increase the indoor air pollution levels.
Significance of Air Infiltration on Building Energy Conservation Design, Standards, and Codes
Authors: Ross HD 
Published: March 2009

Air infiltration in residences accounts for 30 to 75 percent of the heating load, and present design procedures in commercial buildings result in excessive amounts of controlled fresh air introduction to offset air exfiltration losses. Simulation studies on retrofit potential of residences reveal that, while portions of the building heating and cooling loads can be reduced substantially using cost-effective techniques, air infiltration remains a dominant factor in the loads.
With the advent of a priority status for energy conservation, many new standards have been developed. These standards have been of three primary natures: prescriptive, component performance, and performance. Because new residential designs are making buildings tighter, with less air infiltration, three new standards are necessary to follow the trend in design. These standards are: (1) the use of pressurization-evacuation test methods to set a construction quality performance standard, (2) the use of ducted outside air with heat recovery for fresh air introduction to super-tight residences, and (3) the use of ducted outside air to fossil-fuel burning units for combustion purposes.
Guideline Considerations for Selecting Analytical Methods and for Cost Analysis Associated with Monitoring Waters Associated with Alternative Fossil Fuel Technologies
Authors: Rolan RG , Busacca M , Kangas MJ , Mezga LJ , Cornett CL , Faller A 
Published: March 2009

Considerations for developing detailed environmental monitoring plans are described for fossil energy research, development, and demonstration facilities funded by the U.S. Department of Energy (DOE); this approach applies as well to other fossil energy technologies not currently funded by the DOE.
This paper focuses on a systematic approach to technical and cost aspects of methods selection for chemical, physical, biological, and support parameters. Emphasis is placed on methods selection for inorganic and organic chemical parameters for both process and ambient waters.
Evaluation of Utility Wastes for Hazardous Waste Potential
Authors: Weeter DW , Phillips HL 
Published: March 2009

Recently, it has been recognized that coal ashes and scrubber sludges contain a variety of materials, which, if released in soluble form from a disposal area, could be damaging to the quality of surface and subsurface water. The Resource Conservation and Recovery Act of 1976 (RCRA) places these wastes in a special category. There will be stringent controls placed upon their disposal in the future unless it can be shown that hazardous materials, such as heavy metals, will not leach from disposal areas. Fixation is one potential means of limiting the release of materials.
Two toxicant extraction procedures and agitation with unbuffered deionized water were compared on the basis of heavy metal concentrations of the leachate when these treatments were applied to a fixed (crushed and uncrushed) and unfixed dry additive scrubber waste.
Comparison of the methods indicates that the buffering capacity of a waste, as well as its physical structure, determines the magnitude of heavy metals release. It was found that while fixation may reduce the permeability and surface area-to-volume ratio of a waste, the pH-solubility phenomenon is a controlling factor in some cases for the concentration of metals in simulated leachates.
Determination of Aromatic Hydrocarbons in Biologically Treated Water from a Coal Gasification Process
Authors: Dark WA 
Published: March 2009

A high-performance liquid chromatography gradient scheme has been used to separate the aromatic hydrocarbons in the aqueous effluents of a coal gasification process. Samples of raw water, activated sludge, and activated sludge plus carbon-treated effluents were evaluated. By using a simple chromatographic concentration step before separation, the detection of aromatics below the parts-per-million level can be done routinely. Employing multiple detectors aids in peak identification.
The use of activated sludge plus activated charcoal was highly effective in removing aromatic hydrocarbons from the aqueous effluent of this gasifer. The final treated effluent contained some hydroxy-substituted multiring aromatics that were not removed by these treatments.
Sampling Rates and Other Considerations for Selected Passive Air Sampling Techniques
Authors: Palmes ED 
Published: March 2009

Passive samplers for gases use the motion of the gas molecules themselves to furnish the energy for the transfer of gases from the ambient air to a suitable collecting medium. There is no need for pumps, flow regulators, batteries, or other power supplies. Thus the passive sampler can be made much smaller, lighter, less expensive, and much simpler to use and maintain than active samplers. However, passive samplers cannot be used to sample particulates, which, at the particle sizes encountered in industrial or community air, have coefficients of diffusion that are many orders of magnitude lower than those for gas molecules.
All passive samplers depend on Fick's first law of diffusion, which, paraphrased, states that the sampling rate is directly proportional to the coefficients of diffusion of the gas being sampled, the cross-sectional area of the diffusion path, and the concentration of the gas; it is inversely proportional to the length of the diffusion path.
There are two major types of diffusion samplers currently described in the literature. One type uses an air column as the diffusion barrier. Since the coefficient of diffusion for a gas in air is a constant that can be calculated independently, the area and length of the diffusion path, that is, the sampler geometry, can be chosen to give a suitable sampling rate. The other type uses a thin membrane as the diffusion barrier. At the present state of the art, permeation constants for gases through specific membrane materials cannot be calculated from the data available in the literature. Therefore, the permeation devices currently in use depend on empirical calibration of a specific membrane and a specific absorbent for each gas.
A wide variety of sampling rates can be obtained by using passive samplers, but each sampler operates at a fixed rate. The question of which sampling rates or ranges are the most desirable deserves serious attention by industrial hygienists.
Stainless Steel Castings in New York City Water Tunnel No. 3
Authors: Andersen GA , Goldspiel S 
Published: March 2009

Construction of the New York City Water Tunnel No. 3, designed to carry 7.5 million m3 (two billion gallons) of water per day, involves many state-of-the-art technological considerations. This also applies to metallurgical aspects involved and especially those related to stainless steel castings, which are used in large valves 914, 1219, and 2438 mm (36, 48, and 96 in.) in diameter and in their 2438-mm (96 in.) flowmeter components. These entail considerations of long-term corrosion resistance plus demanding dimensional stability over long periods of time and compromises that need not usually be considered for other high-quality stainless steel castings applications, such as chemical plant pressure vessel components.
This paper summarizes specific Bureau of Water Resource Development experiences and decisions reached during its work on the large butterfly valves.
Ferrite Measurement and Control in Cast Duplex Stainless Steels
Authors: Aubrey LS , Wieser PF , Pollard WJ , Schoefer EA 
Published: March 2009

Increased interest has been focused on the ability to predict and control the ferrite content of cast stainless steels with duplex austenitic/ferritic structures. To this end the interrelationship has been examined between the ferrite content in cast CF-type (19Cr-9Ni) stainless steels as estimated by optical microscopy, its magnetic response measured by the Magne-Gage and the Ferritescope, and its chemical composition. The range of ferrite contents examined extended from zero to 48 volume percent in casting sections measuring 27 mm (1 1/16 in.) in diameter to a maximum thickness of 152 mm (6 in.) in a step block casting.
Based upon these tests, statistical relationships were developed to compute the ferrite content from the chemical composition. In addition, calibration procedures were developed for measuring the ferrite content by means of the Magne-Gage and Ferritescope with traceability to the National Bureau of Standards Coating Thickness Standards. The effect of section size on ferrite content is discussed.
Effect of Residual Tin Levels on Mechanical Properties of 12.5Cr Stainless Steel Castings
Authors: Morykwas S 
Published: March 2009

Alloy 12.5 percent chromium (AMS 5350, ASTM A 743; Grade CA 15) is a corrosion-resistant and heat-resistant alloy with which a broad range of mechanical properties may be obtained through thermal processing. It is readily hardened and tempering temperatures up to 732°C (1350°F) produce a broad range of strength coupled with good impact resistance.
This paper presents the problems encountered within master alloy preparation and castings resulting from such preparation, with mechanical properties meeting specification requirements but resulting in field failures upon impact. Specific details regarding the chemical and mechanical property evaluations of the contaminated material are described.
Controlled additions of contaminant (tin) of varying concentrations were made to laboratory melts and subjected to specification test requirements. Test results show the deleterious effect of tin on impact values with no change in results when compared with standard specification mechanical property requirements. A request for changes in chemical composition residual elements has been made with supporting test data.
A New Low-Carbon 16Cr-5Ni Stainless Martensitic Cast Steel
Authors: Niederau HJ 
Published: March 2009

A new low-carbon 16Cr-5Ni stainless martensitic cast steel (S + C 4405) is presented as an advancement of CA6NM with improved corrosion resistance, excellent ductility, less susceptibility to hardening cracks, and good weldability, filling the gap between CA6NM and CF8M. The chemical composition is balanced so that a homogeneous microstructure consisting of annealed martensite with small amounts of δ-ferrite and finely dispersed austenite is obtained after hardening and tempering. Because of limited δ-ferrite, the impact values obtained correspond to CA6NM, and limited austenite still allows yield strength values comparable to those of CA6NM.
Due to its excellent ductility combined with good fabricability, the material is also suitable for cryogenic applications down to −200°C. Furthermore, favorable fatigue tests, and particularly test results in artificial seawater, show a remarkable improvement over CA6NM. Pitting- and crevice-corrosion tests by the International Nickel Co. multiple-crevice tetrafluoroethylene washer method suggest a corrosion resistance between that of CA6NM and CF8M and that this steel is suitable for seawater application in connection with cathodic protection. Stress-corrosion cracking in hydrogen sulfide-containing media was investigated according to the National Association of Corrosion Engineers Specification MR-01-75, and the resistance of 16Cr-5Ni under sour-gas conditions was found to be superior to that of CA6NM. The castability of this alloy was found to be favorable and comparable to that of CA6NM.
These characteristics are important for the following applications: offshore engineering, seawater desalination, chemical and petrochemical industries, shipbuilding, cryogenics, power generation, food industry, paper machine construction, and especially for pumps, compressors, fittings, centrifuges, waterturbines, and ship propellers.