bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Role of Field Measurements in Environmental Radiation Monitoring
Authors: Lowder WM , McLaughlin JE 
Published: March 2009

The operational assessment of releases of radioactivity from nuclear facilities is performed with instruments located in or near the effluent streams or is accomplished by measuring samples collected from these streams. Direct field monitoring is relegated to a lesser role in dose assessment. The reasons for this practice include recognition that effluent measurements are more easily and rapidly performed than environmental measurements. At the same time, by regulation, detailed environmental measurements of mixed character are required around nuclear power plants. This arrangement of priorities tends to produce an unclear understanding of the objectives of field measurements and to reduce theirimportance and hence the quality of the data.
While an optimum radiation monitoring program is site-dependent, the elements of direct field measurements should include the routine deployment of thermoluminescent dosimeters (TLD's) and a few continuous “real time” monitors. Several monitors have been developed in the Environmental Measurements Laboratory and elsewhere and are undergoing field testing. The availability of field monitors provides a desirable capability for the rapid evaluation of special problems in or near the plant that arise from time to time. Moreover, such sensitive measurement methods in conjunction with meteorological data and direct effluent measurements can be employed to verify the models used for setting release limits, to calculate doses to the population around the site, and to maintain a check on effluent measurements. Improved monitoring efforts should instill greater public confidence in the facility's normal operations by detailing actual exposure data in a timely fashion.
Preparations for High-Level Defense Waste Immobilization at Savannah River Plant
Authors: Wiley JR 
Published: March 2009

Methods are being developed to immobilize Savannah River Plant (SRP) wastes in high-integrity glass forms. The waste forms will be suitable for storage in an on-site facility or for shipment to an off-site repository. Alkaline wastes produced in SRP separations plants are currently stored in large, carbon-steel tanks. These wastes consist of a water-soluble fraction (salt cake and supernatant liquor) and an insoluble sludge. The water-soluble fraction contains most of the 137Cs and the insoluble sludge contains most of the 90Sr, waste actinides, and other fission products. 90Sr and l37Cs are the most hazardous radionuclides in 10-year-old waste.
A conceptual solidification process has been developed from laboratory tests with both actual and simulated waste. Engineering design studies are in progress. First, wastes are removed as a slurry from the waste tanks. The sludge is separated from the supernate, and then 137Cs is removed from the clarified supernate by ion exchange. The resulting decontaminated supernate is evaporated to a salt for bulk storage. In the second part of the process, 137Cs is mixed with sludge and the mixture is calcined and then immobilized in borosilicate glass. Off-gas from the calciner and glass melter is treated to ensure that no hazardous materials are released to the atmosphere.
Quality Assurance for Effluent and Environmental Monitoring—A Nuclear Regulatory Commission Overview
Authors: Cohen LK 
Published: March 2009

This paper discusses the Nuclear Regulatory Commission's (NRC's) philosophy and approach to quality assurance (QA) for effluent and environmental monitoring. QA is considered an integral part of any comprehensive monitoring program. The NRC and other regulatory agencies are recognizing the importance of QA and are devoting more effort to incorporating QA programs into all monitoring programs. The rationale and the necessity for QA in the various monitoring programs are discussed. Current and proposed NRC quality-assurance requirements and technical specifications implementing those requirements are reviewed.
The NRC staff has developed a regulatory guide which covers generally accepted elements of QA for monitoring programs from sampling through analysis to reporting. A description of the proposed NRC Regulatory Guide 4.15, “Quality Assurance for Radiological Monitoring Programs—Effluent Streams and the Environment,” is presented.
Discordant Gross Radioactivity Measurements of Natural and Treated Waters
Authors: Janzer VJ 
Published: March 2009

The periodic measurement of gross radioactivity is being widely used as an indicator of the satisfactory quality of community water systems with respect to radioactivity. Requirements for these measurements were defined by the U.S. Environmental Protection Agency in Title 40, Part 141-Interim Primary Drinking Water Regulations, in the 9 July 1976 Federal Register.
Americium-241 apparently is being used by an increasing number of laboratories as an alternative gross alpha activity calibration standard in place of the recommended uranium. Higher alpha counting efficiencies obtained using 241Am result in gross alpha activity analysis differences of up to 100 percent when compared with duplicate sample analyses based on a natural uranium standard. Data presented in this report demonstrate that the use of 241Am as an alternative gross alpha calibration standard will, in effect, double the Federally specified maximum contaminant level for gross alpha activity in community water systems.
Similar problems are associated with gross beta activity calibration standards but the effects are not as pronounced. Comparative counting efficiency data for l37Cs and 90Sr/90Y as gross beta activity calibration standards are given. Gross beta activity differences of up to 25 percent may be obtained on duplicate analyses depending on the beta calibration standard used.
If gross radioactivity measurements are to be useful indicators of water quality, strict adherence to standard procedures and acceptance of single calibration standards used for determining gross radioactivity concentrations in water are needed to achieve industry-wide comparability of results.
Influence of Collector Recombination Lifetime on the Current Gain and Storage Time of High-Voltage Power Transitors
Authors: Hower PL 
Published: March 2009

Two new charge control models are described that account for the effect of collector recombination on transistor current gain, hFE, and storage time, tS. For hFE it is shown that the collector lifetime, τ, is usually large enough that collector recombination can be ignored. As τ is decreased, this assumption is no longer valid, and hFE eventually becomes proportional to τ.
The lifetime is also important in determining tS at low collector currents, where tS is approximately proportional to τ. The resulting trade-off between hFE and tS is determined quantitatively for a particular example by using the proposed models.
Additional data are given that show that both models agree well with experimental measurements. The comparison is made using measured open-circuit-decay lifetimes in the theoretical calculations.
Mechanisms of Erosion of a Ductile Material by Solid Particles
Authors: Maji J , Sheldon GL 
Published: March 2009

Erosion of flat plates and tubular test specimens by spherical 270-μm steel shot showed appreciable differences in the amount of material removed, depending on the condition of the steel shot used. Ductile shot removed considerably less material than brittle or more frangible shot. In addition, lower-velocity exponents were obtained for the tougher, more ductile abrasive.
The evidence presented here supports the view of Tilly that erosion by frangible particles may be viewed as a two-stage process. According to this view, the first stage is due to surface indentation by the particle, forming vulnerable lips around the crater, and the second is due to removal of these lips by radially projecting particle fragments.
Calculated Tolerance of a Large Electric Utility Gas Turbine to Erosion Damage by Coal Gas Ash Particles
Authors: Menguturk M , Sverdrup EF 
Published: March 2009

Erosion damage was estimated for the first stage of a large electric utility gas turbine based on projected particle distributions in the gas leaving the hot gas cleaning system of a pressurized fluidized-bed gasifier system. Based on the assumptions used in making the estimates, cleaning of the turbine expansion gas to a particulate concentration of 0.005 gram per standard cubic metre (0.002 grain per standard cubic foot) with particles larger than 6-μm diameter effectively removed should give satisfactory blade life from an erosion standpoint. Two stages of high-performance cyclone cleanup to 0.1 gram per standard cubic metre (0.5 grain per standard cubic foot) with 0.05 weight percent of 12-μm diameter particles remaining in the gas would wear stator vane trailing edges by 0.25 cm (0.1 in.) thickness (roughly equivalent to full wall thickness in upstream stage vanes) in 10000 h of operation.
The numerical results presented in this paper are based on the estimate that coal ash and sulfur sorbent particles will have, when impacting superalloy turbine materials under turbine conditions, 1/25th of the erosivity of silicon carbide particles impacting a nickel alloy at room temperature. The estimates do not account for the appreciable slowing of the 1- to 3-μm particles in the blade boundary layers before they reach the blading, even though these small particles account for most of the damage. The numerical results are in this way conservative. Actual data on the damage which coal gas particulates do to blade materials under turbine conditions are needed to establish the erosion tolerance of the turbine more accurately.
Effect of an Air-Injected Shroud on the Breakup Length of a High-Velocity Waterjet
Authors: Eddingfield DL , Albrecht M 
Published: March 2009

Air-injected shrouds are used to create an airflow parallel to a high-speed waterjet to examine the effect of the air velocity on the breakup length of the waterjet. Eight shrouds having four different lengths and two different diameters are employed in this study. The air velocity was varied from zero to approximately twice the velocity of the waterjet. The waterjet has an exit diameter of 0.766 mm (0.030 in.) and an exit velocity of 266 m/s (874 ft/s) for all the experimental runs.
Of the shrouds tested, the shortest shroud with the smaller diameter produced the best results for the entire air velocity ranges. The breakup length of the waterjet with a shroud compared to that of a waterjet without a shroud ranges from 1.2 for an air-to-water velocity ratio of zero up to a value of approximately 1.7 for a velocity ratio of 2.0.
Cutting tests on a representative material are planned to establish firmly the benefit of utilizing an air-injected shroud in conjunction with a high-velocity waterjet.
Use of High-Pressure Waterjets in Utility Industry Applications
Authors: Huszarik FA , Reichman JM , Cheung JB 
Published: March 2009

During the past several years, waterjets with pressures up to 408 MPa have become a reliable tool for industry and have been used for a variety of factory applications. In addition, waterjets have been tested for rock cutting in mining and tunnel applications. The utility industries do a considerable amount of work that requires excavation in rock and concrete. The potential of using high-pressure waterjets to meet their field needs has been considered. To date, the telephone, electrical power, and gas industries have conducted studies on the use of high-pressure waterjets. This paper contains descriptions of the various applications of waterjets in the utility industry, descriptions of the appropriate equipment and cutting techniques, discussions of some possible systems and their operating parameters, and an economic analysis of waterjet methods for trenching and pole-hole drilling.
A study was conducted to examine the use of waterjets in utility industry applications. The study was a three-phase program. In the first phase, the possible applications and their significance to utility company operations were examined. In the second phase, a strategy for cutting rock and concrete with waterjets as well as a conceptual system design was developed. Various rock types were tested, and rates were predicted for two specific applications: trenching and pole-hole drilling. In the third phase an economic analysis of the cost of using waterjet methods for trenching and pole-hole drilling was performed and costs were compared with current methods on a per-hole or per-foot of trench basis. In addition, the advantages and disadvantages of waterjet methods on a system basis were compared with those of existing methods.
The study has demonstrated that there is a wide variety of applications for high-pressure waterjets in the utility industry. The study further shows that waterjet devices are both technically and economically feasible. The predicted rates and the costs indicate that, in rock, the waterjet system is better than current methods.
A detailed overview of this study as well as the results are presented in this paper.
Initial Experimental Investigation of Tearing Instability Theory
Authors: Paris PC , Tada H , Ernst H , Zahoor A 
Published: March 2009

An initial experimental investigation was conducted to confirm the theory of tearing instability developed in previous work. A simple testing program was selected which employed 3-point bend specimens with various crack size to specimen depth ratios and an additional spring bar to easily adjust effective specimen span (or loading system compliance).
All stable-unstable behaviors observed in the tests are in good agreement with those predicted by the theory. Thus the present study demonstrates the appropriateness of the tearing instability analysis, presenting guidelines for its further development.
Thickness and Side-Groove Effects on J- and δ-Resistance Curves for A533-B Steel at 93°C
Authors: Andrews WR , Shih CF 
Published: March 2009

A test program was conducted to determine the effects of specimen thickness variations, side grooves, and crack length variations on the deformation and ductile fracture of A533-B, Cl-1 steel at 93°C.
The crack extensions were estimated using the correlation between elastic compliance and crack length. Crack extensions were also estimated using a correlation among crack-opening displacements, load line displacements (δ - VL), and crack length. The inferred estimates of crack extension were supplemented by some measurements on heat-tinted fracture surfaces. The results suggest that the observation of thickness or side-groove effects on crack-extension resistance curves is dependent on the method of measuring crack extension.
The compliance correlation method was less sensitive to crack extension and showed a classical thickness effect: increased crack growth resistance with decreasing thickness, and decreased resistance with the use of side grooves. The δ - VL correlation method was more sensitive to crack extension and showed no effect of thickness or of side grooves on crack growth resistance. The presence of side grooves promoted flat fracture and suppressed shear lips. Specimens without side grooves developed large shear lips.
Fracture Behavior of Stainless Steel
Authors: Bamford WH , Bush AJ 
Published: March 2009

An experimental program has been carried out to characterize the fracture properties of austenitic stainless steel piping and plate material. Characterization was in terms of the J-integral, and several specimen types were tested, including compact specimens, center-cracked panels, and three-point bend specimens.
Several methods of monitoring crack extension were used in the program, including unloading compliance, electrical potential, and acoustic emission in addition to the multiple-specimen heat tinting method used for baseline data. These methods are compared and evaluated in detail.
In addition to determining JIc values for the material, Paris's proposed tearing modulus is evaluated, and various proposed specimen size requirements are discussed.
Use of AIDS Recorded Data for Assessing Service Load Experience
Authors: de Jonge JB , Spiekhout DJ 
Published: March 2009

Inspection periods and safe service lives of transport aircraft are based on an assumed average design load experience. Actual service loads may deviate appreciably from these assumptions.
Fatigue related load data may be obtained on a routine basis from AIDS-recordings. The importance of careful data quality checking is stressed.
Examples illustrate the highly relevant information with regard to aircraft usage and loading environment that may be obtained.
Long Life Random Fatigue Behavior of Notched Specimens in Service, in Service Duplication Tests, and in Program Tests
Authors: Gassner E , Lipp W 
Published: March 2009

The actual service fatigue life of notched steel and aluminum specimens was determined using a special testing device installed in a passenger car and operated by the vertical displacements of a car rear wheel; the specimens are subjected to reversed bending. The tests were carried out over a distance of more than 2 × 105 km. The testing device was equipped with counting instrumentation to ensure direct correlation between the individual test result and the relevant frequency distribution of level-crossings.
The results of the service test series are statistically evaluated and presented as stress/life curves for SAE 5140 and for 2024 T 3 specimens. The corresponding stress/life curves, obtained in service duplication tests were not significantly different.
However, the conventional eight-step program tests overestimate the fatigue life observed in service and service duplication tests by a factor which may be as high as five.
The results of the test series were also compared to fatigue calculations. It was found that the application of a modified linear fatigue damage rule, which does not account for the sequence effect of load changes, yielded fatigue life data which are very much on the nonconservative side. This confirmed the now generally accepted fact that valid fatigue life prediction models must account for the sequence of individual peaks and troughs.
A Unifying Theory for Determining Human Response to Sound
Authors: Higgins TH 
Published: March 2009

In the following work, the relationship between the perceived level of sound (loudness or noisiness) (PLdB) is shown to be a function of the sound pressure (p) squared and the sound frequency (f) squared; that is, PLdB = 10 log (25 p2 f2) in the psychoacoustically important low frequency range up to 4000 Hz. The perceived level of an aircraft takeoff or landing is demonstrated to be equal to the logarithmic sum of the peak perceived levels calculated for each one-third octave band. Effective perceived level (EPLdB) may be calculated by using the procedures contained in the Federal Air Regulations (FAR), Part 36, to correct for the duration of the sound 10 dB below peak level. PLdB and EPLdB show the highest relationship between subject ratings and the physical characteristics of the flyover sounds accounted for by any calculation procedure.
The average rate of growth of annoyance (loudness or noisiness) for a diverse mix of aircraft operations ranging from low to high power levels is shown to be a function of log (k pf)½ for the low frequencies which propagate over long distances with relatively small power loss.
The results are found to be accurate in the useful range of sound pressure levels and frequencies associated with operational aircraft including helicopters, turbofan, turboprop and turbojet powered aircraft. This work, therefore, provides the systems engineer with an easily understood and useful design and evaluation method. The formula developed clearly shows the design engineer and management personnel the relationship between the physical characteristics of an evolving system and its potential impact on human and community response.
Which Populations of Aquatic Bacteria Should We Enumerate?
Authors: Costerton JW , Geesey GG 
Published: March 2009

Bacteria in aquatic systems comprise at least four distinct populations. The planktonic population floates in the water column with the particle-associated population, while the epilithic and epiphytic populations are attached to submerged surfaces, and the sediment population occupies the water-filled spaces of the sediment. Samples taken from the water column include the planktonic and particle-associated bacteria, and core samples include the sediment population, but special techniques are required to sample the epilithic and epiphytic organisms. In all bacterial populations, except the planktonic, the natural adhesion of the cells to surfaces and to each other produces adherent microcolonies whose cohesion presents special problems in bacterial enumeration.
Since we have described freshwater systems in which epilithic bacterial populations are numerically dominant, and since large sediment populations are found in most aquatic systems, it is imperative that bacterial enumeration studies recognize each of these distinct populations. The authors examine the methods available for the enumeration of the bacteria in each distinct population and suggest a holistic approach to bacterial enumeration that can be applied to any aquatic system.
Direct Epifluorescence Enumeration of Native Aquatic Bacteria: Uses, Limitations, and Comparative Accuracy
Authors: Daley RJ 
Published: March 2009

The suitability and comparative accuracy of the acridine-orange epifluorescence direct-count (AODC) technique for determining the numbers, biomass, and metabolic state of aquatic bacteria are reviewed, The AODA method has been indirectly verified as the best available procedure for estimating the total numbers of native aquatic bacteria. It is quantitative, precise, and suitable for use with both pelagic and epibenthic bacteria in all freshwater and marine environments. The development of a standard method should be possible by making only a few technical improvements. However, AODC numbers cannot be converted directly to total carbon biomass because of natural variations in bacterial cell sizes. It is possible that better biomass estimates can be obtained by using combined AODC measurements of cell numbers and cell volumes, but the accuracy of this approach is still to be determined. The alternative, indirect estimation of lipopolysaccharide (LPS), appears, from limited tests, to be accurate for planktonic marine bacteria; however, interference from blue-green algal LPS may restrict its use in fresh waters and sediments.
The distribution of dead, moribund, viable, and growing bacteria within the total population visualized by epifluorescence is unknown. However, recent indirect evidence suggests that most, if not all, native bacteria are viable, but that many are metabolically dormant. Neither the AODC technique nor any of the “living” biomass techniques (plate, membrane, or liquid growth techniques, ATP assays, autoradiography) now used can distinguish the functional states of native bacteria. Autoradiography combined with epifluorescence has the best potential for such measurement, but further assessment is necessary.
The usefulness of the AODC method for descriptive surveys, correlative studies, impact assessment activities, and experimental studies of bacterial dynamics is summarized. Epifluorescence enumeration, in conjunction with activity measurements and filter fractionation procedures, holds considerable promise for examining the productivity and nutrient uptake dynamics of native aquatic bacteria.