bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Stress Relief Time on the Transition Temperature of Linde 80 Welds
Authors: Hall JB , Yoon KK
Published: April 2008

The Babcock & Wilcox Company used Mn-Mo-Ni automatic submerged-arc welds with the Linde 80 flux type for the fabrication of 14 currently operating PWR reactor vessels. Due to the fact that the weld wire was copper-coated (high copper content) and that they have low upper-shelf toughness properties, the welds are limiting with respect to pressurized thermal shock analysis. The welds (reactor vessel, surveillance, and nozzle dropouts) were exposed to stress relief times (postweld heat treatment) ranging from 10–53 h between 593°C (1100°F) and 621°C (1150°F). In analyzing recently acquired master curve reference temperature data (ASTM E1921), it was discovered that there is a stress relief time effect on the transition temperature. The stress relief time effect can be seen in the drop weight TNDT data, but its effect is less clear in the 41 J (30ft-lb) Charpy impact data. In addition, the stress relief time has an effect on yield stress. The stress relief time may have an effect on the irradiation embrittlement of the welds, but the trend is not conclusive. Since there is an effect of stress relief time on the initial transition temperature, it is felt that it is important to test surveillance welds with similar stress relief times as the vessel welds that are being evaluated. Surveillance welds with longer stress relief times can be used to conservatively represent the vessel welds.
The Technical Foundations of a Unified Adjusted Reference Temperature for RPV Fracture Toughness
Authors: Lott RG , Rosinski ST , Server WL
Published: April 2008

The use of a reference temperature to define the transition from ductile-to-brittle behavior is a well-established practice in reactor pressure vessel integrity analysis. Current procedures for analysis of irradiated pressure vessel steels use an Adjusted Reference Temperature (ART or RTPTS) that shift the unirradiated RTNDT value based on Charpy data and apply additional margins. The recent adoption of an ASTM Standard Test Method for Determination of Reference Temperature, To, for Ferritic Steels in the Transition Range (E 1921) has made direct determinations of fracture toughness reference temperature in irradiated materials using Master Curve feasible. ASME Code Case N629 recognizes the potential of this new technology as an alternative means of determining an ART value for use in reactor pressure vessel integrity analysis. This alternative approach has been used in recent plant specific submittals to the NRC. ASTM sub-committee E10.02 is currently considering adopting a standard to provide a unified definition of the Adjusted Reference Temperature. This unified definition would provide consistent procedures for using either RTNDT or Master Curve based definitions of ART. This unified definition would provide common margins for the two approaches and assure a consistent level of confidence in the analysis. The statistical basis of the Master Curve makes it possible to establish a more rational basis for the margins applied in both approaches.
Effects of Copper Content on the Tensile Properties of Iron-Copper Alloys
Authors: Toloczko MB , Kumar AS , Hamilton ML , Jumel S , Van Duysen JC , Snead LL
Published: April 2008

Miniature tensile specimens of high purity iron and iron-copper alloys containing 0.1 and 0.3 weight percent copper were irradiated at 150°C and 290°C in the HFIR to 0.025 and 0.1 dpa. Following irradiation, room temperature tensile tests were performed. The effect of copper content on the yield stress (YS), ultimate tensile strength (UTS), uniform elongation (UE), and total elongation (TE) were examined for both unirradiated and irradiated specimens. For the unirradiated specimens, YS and UTS increased by 10% or less when copper in the amount of 0.1% was added, while UE decreased by about 30% and TE decreased by about 20% when copper in the amount of 0.1% was added to the pure iron. There was almost no further change in tensile properties when the copper content was increased from 0.1% to 0.3%. The effect of irradiation at 290°C to 0.1 dpa was to increase the strength and decrease the ductility of all the materials. Greater percent changes in tensile properties were observed in the Fe-XCu alloys after irradiation suggesting that copper contributes to the formation of extended defects at these temperatures.
Predicting the Reliability of Ceramics Under Transient Loads and Temperatures with CARES/Life
Authors: Nemeth NN , Jadaan OM , Palfi T , Baker EH
Published: April 2008

A methodology is shown for predicting the time-dependent reliability of ceramic components against catastrophic rupture when subjected to transient thermomechanical loads (including cyclic loads). The methodology takes into account the changes in material response that can occur with temperature or time (i.e., changing fatigue and Weibull parameters with temperature or time). This capability has been added to the NASA CARES/Life (Ceramic Analysis and Reliability Evaluation of Structures/Life) code. The code has been modified to have the ability to interface with commercially available finite element analysis (FEA) codes executed for transient load histories. Examples are provided to demonstrate the features of the methodology as implemented in the CARES/Life program.
Fatigue Life Variability Prediction Based on Crack Forming Inclusions in a High Strength Alloy Steel
Authors: Sharpe PS , Hillberry BM , Craig BA
Published: April 2008

Fatigue cracks in metals have been observed to form at nonmetallic inclusions in the matrix of the material, with the size of such features influencing fatigue life. A probabilistic method was used to predict the variability of fatigue life in quenched and tempered AISI 4340 steel. Crack growth analyses, presented as cumulative distribution functions of probability of failure, were made at two stress levels by growing inclusion size fracture mechanics flaws using an existing linear elastic fracture mechanics crack growth model. Initial flaw sizes were obtained from two separate distributions: one representing the overall inclusion population, and the other a subdistribution representing crack forming inclusions. In general, analyses correlated well with experimental lives, typically being within 25%. The two initial flaw size distributions produced similar results; however, predictions based on the total inclusion distribution were heavily dependent on the threshold value. With the appropriate value of crack growth threshold, good correlation with variability can be made without requiring fatigue testing, particularly for the more critical shorter lives.
Application of Probabilistic Fracture Mechanics in Structural Design of Magnet Component Parts Operating Under Cyclic Loads at Cryogenic Temperatures
Authors: Yatomi M , Nyilas A , Portone A , Sborchia C , Mitchell N , Nikbin K
Published: April 2008

This paper presents a methodology for the use of probabilistic fracture mechanics concepts to estimate the design fatigue life and reliability of structural materials used in superconducting coils and magnet intercoil components of the International Thermonuclear Experimental Reactor (ITER). The orbitally welded conductor jackets of superconducting coils are subjected to fluctuating tensile stresses. The paper uses fatigue crack growth (FCGR) data at 7K from type 316LN stainless steel, in parent and weld material conditions, to predict fatigue crack growth rates using Monte Carlo analysis. Two stages are considered in which scatter could be quantified in the analysis. Initially, the unknown in crack length is taken as a stochastic variable. Secondly, the model assumes that the scatter observed in the correlation of the FCGR data versus ΔK is directly due to factors such as testing methods, measurement, material, and geometric variability and can therefore be quantified statistically. Either a normal or lognormal distribution of the scatter is assumed depending on the parameter. The purpose of this approach is to illustrate some of the advantages over a deterministic approach that most design codes use. An example is presented that compares the design life of a conductor jacket section containing a single crack and multiple cracks. A comparison of a sensitivity analysis for multiple cracks, for failure times at probabilities of 1 % and 0.001 %, with times calculated from a deterministic analysis using appropriate safety factors, suggests that the deterministic analysis give less conservative failure times.
Enhancement of Thermomechanical Fatigue Resistance of a Monocrystalline Nickel-base Superalloy by Pre-rafting
Authors: Neuner FC , Tetzlaff U , Mughrabi H
Published: April 2008

In γ'-hardened monocrystalline nickel-base superalloys having a negative γ/γ' lattice misfit, the prior introduction of so-called γ/γ' rafts aligned parallel to the stress axis (by a small creep pre-deformation in compression) has been shown to enhance both the high-temperature isothermal fatigue strength and the tensile creep resistance. It was hence of interest to perform a systematic study of the thermo-mechanical fatigue (TMF) behavior of specimens of a monocrystalline nickel-base superalloy with the main aim to test whether an initial γ/γ' raft microstructure can also enhance the TMF resistance. The experiments were performed on [001]-orientated monocrystalline specimens of the superalloy SRR 99 which contained either the initial γ/γ'-microstructure with cuboidal γ' precipitates or a γ/γ' raft microstructure aligned roughly parallel to the stress axis. The latter was introduced by a small compressive creep deformation of less than 0.4% at a temperature of 1050°C and a stress of 120 MPa. Different strain-controlled TMF cycle forms were employed. However, in most tests a counter-clockwise-diamond (CCD) cycle (temperature interval ΔT = 600°C–1100°C) was used with a total strain rate of 6.67∙10-5 s-1. This CCD cycle is considered to be close to service conditions. The mechanical strain range Δεm was varied in the range of Δεmech = 1%, leading to fatigue lives in the order of some 1000 cycles. It could be shown that pre-rafting in compression enhances the TMF fatigue life significantly for all cases of CCD-cycles investigated.
Miniature Thermomechanical Ramping Tests for Accelerated Material Discrimination
Authors: Roebuck B , Gee MG , Gant A , Loveday MS
Published: April 2008

Conventional thermomechanical fatigue tests are usually performed under conditions of close control of strain amplitude, temperature cycle, loading rates, and frequency—mainly for the purposes of developing data for design. However, in some cases, it is helpful to have a rapid assessment of the likely response to specific thermomechanical environments of those materials, particularly when new materials are being developed, or when material is in short supply, or when material production processes have been changed.

For this purpose a miniature test system, developed at the National Physical Laboratory, has been evaluated for its ability to discriminate between different materials under these general circumstances, but with conditions of ramping load or temperature to accelerate material response and failure characteristics.

The miniature test system uses D-C current to heat test pieces to appropriate temperatures, up to 1300°C in under a minute if necessary, using small cross-sectional (2 × 1 mm) rectangular samples. Strain was measured using changes in electrical resistance of the central 2–3 mm of the gage length (16–20-mm grip separation), where temperature was known to be acceptably uniform.

Several material types were studied, including a powder metallurgy high speed steel, cemented carbides, a refractory metal, Ta, and a Ni-base superalloy. Tests were performed under combinations of either ramping load or temperature ramping. The system was shown to discriminate well between the different materials under various conditions of the thermomechanical environment with respect to the effects of accumulated strain.
Randomization Tests: A Statistical Tool to Assess Heavy Metal Pollution in Caí River Basin Sediments (RS, Brazil)
Authors: Rodrigues MLK , Raya-Rodríguez MT , Pillar VD
Published: April 2008

This study evaluated the use of statistical randomization tests in data analysis regarding heavy metals content in sediments from the Caí River basin (Brazil). During one year, four samplings took place at eleven sites in the Caí River and tributaries. The results showed significant differences between some locations, enabling spatial segregation of sites affected by natural and anthropic sources. Considering a significance level (α) of 5%, the control station, above polluted areas, showed the best quality; Caí River station after the mouth of Pinhal/Belo stream indicated influence from the industrial complex of Caxias do Sul region, as well as copper compounds use in vineyards; and the Cadeia and Forromeco streams showed effects of natural contribution from basalts and surface runoff on naked soils. For α=10%, it was possible to identify chromium pollution by tanneries in the Cadeia stream. Long-term studies should be performed, since understanding temporal aspects such as alteration processes in sediments involves a much longer time scale.
Characterization of Contaminated Sediments in Hamilton Harbour, Lake Ontario
Authors: Zeman AJ , Patterson TS
Published: April 2008

Sediments in many harbors and connecting channels of the Great Lakes have been negatively impacted by industrial, agricultural and municipal discharges and by atmospheric deposition. Contaminated sediments may pose risks to both human health and to aquatic environments. All 42 U.S. and Canadian Areas of Concern (AOCs), designated by the International Joint Commission (IJC), have problems associated with the occurrence of contaminated sediments. Remedial Action Plans, which have been prepared for these areas, include sediment remediation plans. Appropriate and cost-effective sedimentological, geotechnical and geochemical investigations are required to determine the degree and extent of contamination. The methodology used in sediment characterization includes in-situ penetration tests, core sampling, acoustic bottom-classification systems, side-scan surveys and in-situ porewater samplers. Contaminated sediments are typically characterized for chemical concentrations of contaminants of interest in terms of both areal extent and vertical distribution. Site specific examples of sediment analyses and characterization for remediation projects are discussed for three sites within Hamilton Harbour, Ontario, where very heterogeneous sediments exist.
Use of Selective Sequential Extraction for the Remediation of Contaminated Sediments
Authors: Mulligan CN , Azma BD
Published: April 2008

The interaction of contaminants with sediments is a very complex phenomenon and means are required to understand this matter more fully. To determine the speciation of metals in sediments (the distribution of elements among chemical forms or species), specific extracts are used in a process called sequential selective extraction. This method can be used to determine if heavy metals are removable by remediation techniques or to predict removal efficiencies. Sequential extraction can be employed for the evaluation of the most appropriate sediment remediation technology and for monitoring remediation procedures. A biosurfactant, rhamnolipid, was used to remove organic-bound copper and carbonate-bound zinc. Exchangeable, carbonate, reducible oxide and organic fractions are amenable to washing techniques, and residually bound contaminants are not economical or feasible to remove. This information is important in designing the most appropriate conditions for sediment washing.
Effects of Overburden Stresses on Soil Reclamation by Electroosmosis
Authors: Kabir A , Picornell M
Published: April 2008

A fine-grained soil stock was cleaned of organic matter and soluble salts. then the slurry was repeatedly washed with a barium-chloride solution to ensure a known pore solution chemistry. Test specimens were prepared by first consolidating the slurry in triaxial cells under varying cell pressures, and secondly by trimming the specimens to be placed into electroosmotic cells enclosed in rubber membranes with the same confining pressure applied on the membrane as had been used in the consolidation phase. The electroosmotic treatment was performed at constant voltage gradient and was continued until the electrical conductivity of the effluent was similar to that of deionized water. The “postmortem” investigations of the treated specimens show that the confining pressure has a significant effect on the removal of barium by the electroosmotic treatment.
Retention of Heavy Metals in the Post '96 Flood Sediment Layer Deposited in the Saguenay River, Quebec, Canada
Authors: Galvez-Cloutier R , Muris M , Locat J , Bourg C
Published: April 2008

In July 1996 during a 50 year event flood, a new layer of sediments composed of debris, gravel and fine materials was transported and deposited over an ancient, one meter contaminated layer of sediments in the Saguenay River Fjord and Ha! Ha! Bay floors. During the Industrial Revolution years, various metallurgic, plastic, aluminum and pulp and paper production industries discharged their wastes on these waters, resulting in the high contamination of both water and sediments. This contamination limited the exploitation of fish and seafood. Given that the new layer is composed essentially of cleaner material, the zone is presenting important changes in the direction of a healthier environment. The Canadian Government and some of the surrounding industries aim to assess the new potential of the zone and its environmental safety. At present, it represents over a million-dollar study.

This part of the Saguenay project aimed to recognize and evaluate the capacity of the new layer to contain and retain the contaminants left at the bottom layer. Particular interest is given to mercury and to heavy metals such as Pb, Zn, Cd, and Ni and to their geochemical distribution among natural adsorbing materials such as clays, oxides, carbonates and organic matter.

The paper presents the recognition and sampling mission on the Alcide Horth Ship, the contamination profiles given in two dimensions (length and depth), the geochemical distribution of heavy metals on the contaminated layer, transition layer and new layer as well as the evolution of their retention and transfer. Discussion and relations with common sediment characteristics such as grain size, cation exchange capacity and surface area are also given. Sequential selective extraction has been used jointly with scanning electron microscopy (SEM) to study heavy metal species.
Instantaneous RRMI of Iron Rods in Reduced Gravity
Authors: Edwards APR , Chiffoleau GJA , Maes MJ , Steinberg TA
Published: April 2008

Standard upward-burning promoted ignition tests (“Standard Test Method for Determining the Combustion Behavior of Metallic Materials in Oxygen-Enriched Atmospheres,” ASTM G4-124 [1] or “Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion,” NASA-STD-6001, NASA Test 17 [2]) were performed on cylindrical iron (99.95% pure) rods in various oxygen purities (95.0–99.98%) in reduced gravity onboard NASA JSC's KC-135 to investigate the effect of gravity on the regression rate of the melting interface. Visual analysis of experiments agrees with previous published observations showing distinct motions of the molten mass attached to the solid rod during testing. Using an ultrasonic technique to record the real-time rod length, comparison of the instantaneous regression rate of the melting interface and visual recording shows a non-steady-state regression rate of the melting interface for the duration of a test. Precessional motion is associated with a higher regression rate of the melting interface than for test periods in which the molten mass does not show lateral motion. The transition between the two types of molten mass motion during a test was accompanied by a reduced regression rate of the melting interface, approximately 15–50% of the average regression rate of the melting interface for the entire test.
Promoted Ignition-Combustion Behavior of Cast and Wrought Engineering Alloys in Oxygen-Enriched Atmospheres
Authors: Zawierucha R , Samant AV , Million JF
Published: April 2008

Promoted ignition-combustion has been used to describe a situation in which a substance with low oxygen compatibility ignites and supports the combustion of a more combustion-resistant material. Previous work has been reported on the investigation of this phenomenon as it relates to carbon steel, stainless steels and a number of significant engineering alloys in the nickel, cobalt and copper families.

Reported in this paper are the results of promoted ignition-combustion tests of wrought nickel alloys, cast nickel alloys and nickel alloy weld filler metals in oxygen atmospheres at pressures up to 34.5 MPa. The specific alloys tested were: CX2MW, CW2M, Hastelloy C-4, Hastelloy X, Inconel 601, Inconel 617, Inconel Welding Electrode 117, Inconel Welding Filler Metal 82 and 602CA.
Effect of Molding and Machining on Neoflon CTFE M400H Polychlorotrifluoroethylene Rod Stock and Valve Seat Properties
Authors: Waller JM , Newton BE , Beeson HD
Published: April 2008

The effect of processing and machining on the dimensional stability of polychlorotrifluoroethylene (PCTFE) rod stock and oxygen gas cylinder valve seats was investigated. Initial testing focused on two types of extruded rod stock and one type of compression-molded rod stock made from the same lot of Neoflon® CTFE M400H. To accommodate valve seat manufacturer preferences for certain rod stock diameters, two representative diameters were used (4.8 mm (0.1875 in.) and 19.1 mm (0.75 in.)). To encompass a variety of possible sealing configurations, seven different valve seat types with unique geometries or machining histories made from the above types of rod stock were tested. Property changes caused by processing and machining were evaluated using thermomechanical analysis (TMA), specific gravity, differential scanning calorimetry, zero strength time, and intrinsic viscosity. The dimensional stability of valve seats as revealed by TMA tended to be more dispersed and grouped by manufacturer and did not overlap rod stock TMA data, suggesting that machining had an important effect on seat properties. These and other findings are discussed in the context of process history, annealing, percent crystallinity and molecular weight. Structure-property characteristics of emulsion-polymerized Kel-F® 81 and suspension-polymerized Neoflon M400H PCTFE are compared, and the merits of current PCTFE specifications evaluated.
Minor Traumatic Brain Injury “mTBI” in Ice Hockey and Other Contact Sports: Injury Mechanisms at the Macro and Histological Levels and Prevention Strategies
Authors: Biasca N , Simmen HP
Published: April 2008

MTBI is caused by the inertial effect of a mechanical impact to the head with sudden rotational acceleration forces. mTBI produces, in the less severe cases, only transient disturbances of ionic homeostasis with temporary disturbances of brain function. Depending on the severity of the trauma, animal and human studies have demonstrated focal intra-axonal alterations in neurofilamentous/cytoskeletal network and impairment of axoplasmatic transport, which may lead to progressive axonal swelling, detachment or even cell death over a period of hours or days, the so-called process of delayed axotomy. Disturbances of ionic homeostasis, acute metabolic changes and cerebral blood flow alterations compromise the ability of neurons to function and render brain cells vulnerable. These processes may predispose brain cells to a vulnerable state for an unknown period; therefore we recommend that any confused player with or without amnesia should be taken off the ice and not be permitted to play again for at least 24 hours.
The Effect of Aging on Mechanical Properties of Melt-Annealed Highly Crosslinked UHMWPE
Authors: Bhambri S , Gsell R , Kirkpatrick L , Swarts D , Blanchard CR , Crowninshield RD
Published: April 2008

Crosslinking has been shown to improve significantly the wear resistance of ultra high molecular weight polyethylene (UHMWPE), both in joint simulator tests and in clinical use. High-energy ion radiation, when used to induce crosslinking in UHMWPE, produces free radicals. In the presence of oxygen, the free radicals have been shown to be responsible for oxidative degradation of polyethylene. A melt-anneal treatment of highly crosslinked UHMWPE substantially eliminates the free radicals to an undetectable low level.

The aim of this study was to determine the effect of accelerated oxidative aging on the mechanical and fracture properties of melt-annealed highly crosslinked UHMWPE. Compression molded GUR 1050 UHMWPE was crosslinked by electron-beam irradiation at 100 ± 10 kGy and was followed by a melt-anneal treatment. Both melt-annealed highly crosslinked and conventional gamma irradiated in nitrogen UHMWPE were exposed to an accelerated oxidative challenge in the laboratory. The tensile mechanical properties and crack growth resistance curves (J-R curves) determined for oxidative aged melt-annealed highly crosslinked UHMWPE were either equivalent or superior to the oxidative aged conventional gamma irradiated UHMWPE. The difference in tensile mechanical properties and J-R curves for non-aged and oxidative aged melt-annealed crosslinked UHMWPE was insignificant, indicating that oxidative aging had no detrimental effect on mechanical and fracture properties of melt-annealed highly crosslinked UHMWPE.
Development of a Model for Testing Third Body Wear of UHMWPE Acetabular Components
Authors: Bragdon CR , O'Connor D , Muratoglu OK , Harris WH
Published: April 2008

The purpose of this paper is to describe the development of a new wear test protocol utilizing third body particulate debris in order to assess conventional and highly cross-linked polyethylene components. A series of tests were performed using the Boston Hip Simulator to evaluate different types of particles for possible use. Modifications to the simulator are described which ensure that the third body particles can be maintained in suspension. In this series of studies, alumina particles in a concentration of 0.15mg/cc appeared to provide the most effective challenge to the wear resistance of UHMWPE while at the same time not creating unrealistic destruction to the femoral head. In all of the experiments, under all conditions, the WIAM highly crosslinked polyethylene acetabular components resisted the effects of the third body particles and the concomitant changes in the femoral heads distinctly better than the conventional UHMWPE.
Zen and the Art (or is it Science) of a Perfect Analysis
Authors: Nadkarni RAK
Published: April 2008

An analytical laboratory in any industry plays a crucial role in product quality management and ultimate customer satisfaction. Some factors need to be considered for an aspiring laboratory to become a perfect performer. These range from sampling, calibration, contamination control, and use of valid test methods to statistical quality assurance. Some approaches may be utilized to achieve a perfect analysis including: staff training, participation in proficiency testing, use of standard reference materials in the analytical sequence, internal and external audits, agency accreditation, continuous improvement program, benchmarking, etc. Laboratories managed in this way show demonstrated superiority in data precision and accuracy over the labs which do not practice such quality management. Well-managed industrial laboratories can have insignificant laboratory sigma compared with manufacturing variability in the plant production. For a flawless perfect analysis, determination to excel, mental discipline to stay the course, willingness to overcome inertia and resistance, and focus on producing a perfect analysis at all levels of laboratory staff are essential.
The Use of Microwave Digestion and ICP to Determine Elements in Petroleum Samples
Authors: Hwang JD , Horton M , Leong D
Published: April 2008

ICP-AES analyses are prone to errors caused by changes in the power level, nebulization rate, plasma temperature, and sample matrix. This is especially true for ICP-AES and ICP-MS organic applications in the petroleum industry where extremely complicated sample matrices are common. As a result, accurate analyses of petroleum lubricants, lubricant additives, fuels, crude oils, residues, and related materials often require bracketing with matrix matched standards, the use of internal standards, and a flexible ICP-AES/ICP-MS system. Many new innovative analytical instruments were developed to better improve elemental analysis in the last few decades. However, sample preparation remains the formidable challenge because it is always labor-intensive, cumbersome, and does not permit fast operation. It is encouraging to see the application of microwave radiation field as the energy source for sample digestion to pursue more reliable, but simpler, safer, more rapid, and less expensive methods, particularly in the petroleum industry.
Fuel Analysis by Filter Furnace Electrothermal Atomic Absorption Spectrometry
Authors: Tittarelli P , Priola M , Ricchiuto S , Katskov DA , Ngobeni P
Published: April 2008

The determination of Mn, Fe, Co, and Zn was performed in gasoline, jet, and diesel fuel samples by electrothermal atomic absorption spectrometry using the Transverse Heated Filter Atomizer (THFA). Thermal conditions were experimentally defined for the investigated elements.

The elements were analyzed without the addition of chemical modifiers, using organometallic standards for the calibration. Gasoline samples were analyzed directly, while jet and diesel fuel samples were diluted 1+3 with n-heptane.

The following LODs were obtained using 40 μL injections: 0.08 μg/L Mn, 0.35 μg/L Fe, 0.54 μg/L Co, and 0.06 μg/L Zn. The limits of determination, calculated for diesel and jet fuel samples, were 1.2 μg/kg Mn, 4.9 μg/kg Fe, 7.6 μg/kg Co, and 0.8 μg/kg Zn. The corresponding limits of quantitation for gasoline samples were about four times higher.
Trace Levels of Sulfur in the Fuels of the Future: Analytical Perspective
Authors: Nadkarni RAK
Published: April 2008

Sulfur levels in both gasoline and disel fuels are being restricted because of environmental pollution concerns throughout the world. The U.S. Environmental Protection Agency has mandated the levels of sulfur which may be allowed in most road and off-road vehicles. Although there are many standard test methods available for determining sulfur in petroleum products, presently only about four can qualify for their usefulness at the expected low levels in the future fuels. A large interlaboratory study undertaken by ASTM to estimate the capabilities of these methods is described. Also, data from the ASTM interlaboratory crosscheck programs is reviewed to identify the trends that the industry laboratories are showing. Finally, a brief overview of some new methods being developed in the industry for such analyses is presented.
Low-Level Sulfur in Fuel Determination Using Monochromatic WD XRF—ASTM D 7039-04
Authors: Chen ZW , Wei F , Radley I , Beumer B
Published: April 2008

A monochromatic wavelength dispersive X-ray fluorescence (MWDXRF) technique has been successfully developed for measuring low-level sulfur in fuel. In this technique, two doubly curved crystal (DCC) optics were used to provide monochromatic excitation and fixed channel wavelength dispersive analysis. Using highly efficient DCC optics, compact bench top MWDXRF analyzers for sulfur analysis have been successfully produced. A new ASTM standard test method for low-level sulfur determination in diesel and gasoline, D7039-04, has been developed based on this technique. Data for ultra-low-sulfur fuel were collected and analyzed using this new method. In this paper, the results of repeatability, reproducibility, and bias are presented and discussed. The repeatability for 10-ppm sulfur fuel was shown to be around 1 ppm. The pooled limit of quantification (PLOQ) for ultra-low-sulfur diesel was found to be less than 1.5 ppm in this study. The reproducibility of 15-ppm sulfur diesel fuel was determined to be better than 3 ppm (95 % confident level). The limit of detection for a single analyzer was found to be 0.36 ppm. The effect of matrix composition was investigated. The correction due to matrix for low-level sulfur diesel and gasoline is generally not significant.
Pyro-Electrochemical On-Line Ultra Low Sulfur Analyzer
Authors: Rhodes JR
Published: April 2008

Current and upcoming regulations worldwide require maximum concentrations of sulfur in fuels to be in the range 10–50 mg/kg. This paper describes a new on-line analyzer for ultra low sulfur, the first to employ “Pyro-electrochemical” technology, which is significantly simpler than other pyrolysis methods such as Pyro-microcoulometry and Pyro-UV fluorescence.

The technology is based on ASTM D 6920. The instrument is described with special reference to the modifications needed to adapt the technique to on-line analysis. Experimental results are given for long term stability, sensitivity, precision, speed and linearity of response, temperature stability, and sensitivity to nitrogen.
Sampling and Analysis of Mercury in Crude Oil
Authors: Wilhelm SM , Kirchgessner DA , Liang L , Kariher PH
Published: April 2008

Sampling and analytical procedures used to determine total mercury content in crude oils were examined. Three analytical methods were compared with respect to accuracy, precision, and detection limit. The combustion method (U.S. EPA 7473 hybrid) and a commercial extraction method (non-standard) were found adequate to provide a good combination of sensitivity and accuracy, while instrumental neutron activation analysis was found to suffer from interferences from elements other than mercury (Ni, Se) that are typically found in crude oil. Aliquot removal and processing steps were found to be important to accuracy and precision of the combustion method. Potential errors caused by incomplete homogenization and loss of volatile mercury were investigated in detail. Homogenization of oils that contain suspended mercury compounds was found important to allow retrieval of representative aliquots for analysis. Ultrasonication at slightly elevated temperature yielded the more reproducible and higher magnitude results. It was discovered that volatile mercury can be lost from sample containers when they are opened to remove aliquots. Alternative sample containers and aliquot removal techniques were developed that minimized loss of volatile mercury. Speciation experiments were utilized to determine the identity of volatile species and the rates at which they are lost from containers. Both elemental mercury and dimethylmercury were identified as volatile mercury components of one freshly sampled crude oil.
Determination of Total Mercury in Crude Oil by Combustion Cold Vapor Atomic Absorption Spectrometry (CVAAS)
Authors: Fox BS , Mason KJ , McElroy FC
Published: April 2008

Unlike many heavy metals, mercury is a long-range air and water pollutant whose load on the environment is increasing. According to published reports, a major source of atmospheric mercury is the burning of coal for electrical power generation. However, certain crude oils may contain up to several hundred ng/g of total mercury. Accurate analysis of total mercury in crude oil is the first step in determining the value of a crude oil and one's ability to process the material within the refinery, while generating finished products. This paper details the use of Combustion Cold Vapor Atomic Absorption Spectrometry (CVAAS) technology for the analysis of crude samples and distillation cuts. The instrument described in the report is one of several instrument methods currently being evaluated by groups in industry and government. The use of a boat-inlet sample introduction system allows crude oil and other types of material to be analyzed without acid digestion. The strengths and weaknesses of the combustion-CVAAS technique, along with a year's worth of operating experience, will be presented from the user's perspective.
Experimental and Numerical Study of Oxygen Diffusion Through a Partially Hydrated Needle-Punched Geosynthetic Clay Liner
Authors: Bouazza A , Rahman F
Published: April 2008

Laboratory experiments were carried out in a closed cell to determine the effective diffusion coefficient of gaseous oxygen through a needle punched geosynthetic clay liner with a top geotextile carrier impregnated with bentonite. It was observed that the diffusion coefficient decreased with the increase of the degree of saturation. The effective diffusion coefficients were obtained by fitting the time oxygen concentration data to curves obtained from a finite layer contaminant transport computer program (POLLUTE®). These curves were verified by an empirical model and finite element programs (SEEPW®/CTRANW®). The analysis of the data obtained in the present investigation show that the empirical model and the theoretical solutions provided by the finite element method and the finite layer method, represent observations quite well.
Comparison of Fracture Toughness of Irradiated Reactor Vessel Welds — Predicted by ASTM E 900 and Measured
Authors: Yoon KK , Pavinich WA
Published: April 2008

Recently, a new predictive model has been developed by the NRC and is being implemented in ASTM Standard E 900, that addresses radiation-induced embrittlement of ferritic steels. The model is based on extensive Charpy impact energy data of irradiated reactor vessel steels obtained from surveillance programs. The final application of this new method is to predict fracture toughness of irradiated materials to determine pressure-temperature curves for nuclear power plant operation and RTPTS values in compliance with the current regulatory rules for the nuclear-utility industry.

In this paper, the predicted fracture toughness of irradiated reactor vessel welds is compared with that of irradiated material. The degree of conservatism in the Charpy impact energy based predictive model is assessed by comparison with the actual fracture toughness of irradiated materials.
The Effects of Flux on Radiation Embrittlement of Low-Copper Pressure Vessel Steels
Authors: Xu Y , Jia X , Zhang C , Ning G , Yu Q
Published: April 2008

The effects of neutron flux (E>1MeV) on the radiation embrittlement of the low-copper RPV steels are investigated. Tested materials include the forging matrix (JF) weld (JW) of Japan's SA 508-3 steel as well as the matrix (CF) and weld (CW) of China's domestic RPV steel. JF and CF were irradiated to fluences from 3.2 to 4.9 × 1023n/m2(E>1MeV) at 280±5°C, JW and CW irradiated to fluences of 1.4 and 1.5 × 1023n/m2 at 290±5°C, respectively, in the test reactor. JF and JW are also used as surveillance specimens for PWR RPV, and two sets of surveillance data have been acquired. The experimental results indicate that the transition temperature shifts (ΔRTNDT) for JF irradiated in the test reactor are larger than those from surveillance specimens, when these ΔRTNDT are normalized to an effective fluence of 2×1023n/m2 (E>1MeV) and an effective temperature of 290°C. This shows notably the influence of neutron flux on ΔRTNDT. The mean ΔRTNDT for CF and CW is about 0.7 times that for JF and JW in terms of the normalized data, which imply the influences of the impurities besides Cu and microstructures on radiation embrittlement of low-copper RPV steels.
Technical Basis for Application of the Master Curve Approach to Reactor Pressure Vessel Integrity Assessment
Authors: Server WL , Rosinski ST
Published: April 2008

The American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code reference toughness curves are based upon an approach which utilizes a material normalizing and indexing parameter, RTNDT. This parameter is based upon the combined results from Charpy V-notch and drop-weight nil-ductility transition temperature tests as defined in the ASME Code. In many cases, this indexing parameter is overly conservative relative to the real toughness of ferritic reactor pressure vessel (RPV) steels, and a more direct index and measure of the true fracture toughness is desired. The Master Curve fracture toughness method, recently issued as ASTM Standard Test Method E 1921-97, is a better indicator of fracture toughness behavior in terms of a directly measured toughness index, To, and statistically-derived tolerance bounds. This method is technically more sound than the RTNDT approach and provides use of the statistical nature of measured fracture toughness properties (including use of surveillance materials). The Pressure Vessel Research Council (PVRC) is presently investigating application of the Master Curve approach for implementation in the ASME Code. The Electric Power Research Institute (EPRI) is supporting development of alternative RPV integrity assessment approaches, which includes documentation of the technical basis for application of the Master Curve approach. An EPRI document has been written that supports the ASME Code activities to allow utility use of the Master Curve approach. The results of that document for application of the Master Curve approach to RPV integrity assessment are summarized in this paper. Examples illustrating applicability of the Master Curve approach are presented.
Effect of Irradiation on Fracture Toughness in the Transition Range of RPV Steels
Authors: Onizawa K , Tobita T , Suzuki M
Published: April 2008

The effect of irradiation on cleavage fracture toughness in the ductile-brittle transition range of RPV steels was studied using precracked Charpy-V (PCCv) specimens. Four kinds of RPV steels of ASTM A533B class 1 made by Japanese steel makers were used for this study. Neutron irradiation to PCCv specimens was carried out at JMTR. An approach based on the weakest link theory was applied to analyze the specimen size effect and the scatter of fracture toughness. The scatter of fracture toughness was confirmed to have a Weibull type distribution. Irradiation effect on the scatter was found insignificant. The fracture toughness transition curves were determined by PCCv data according to the master curve approach and the Japanese code. The shift of the master curve due to neutron irradiation was somewhat greater than the Charpy 41J shift. The scheme to estimate the lower bound of fracture toughness was also studied.
Influence of Thermal Neutrons on the Hardening and Embrittlement of Plate Steels
Authors: Jones RB , Edens DJ , Wootton MR
Published: April 2008

A series of C-Mn pressure vessel plates and other steels containing various levels of copper, phosphorus and boron were irradiated at 240°C in two differing neutron spectra in the Halden reactor. Hardening and embrittlement data obtained after exposure in a highly thermalised neutron spectrum with dpathermal(>1keV)/dpafast(<1keV) = 2 were compared with data obtained after exposure to a cadmium-shielded spectrum with dpathermal/dpafast = 0.01. Exposure times varied from 85 to 251 days at a mean fast dpa dose rate of 6 × 10-11 dpa/second. For C-Mn plate steels containing low levels of impurity boron, the respective shifts in yield stress and Charpy transition temperature were always greater after exposure to the thermalised spectrum when compared with exposures to the cadmium-shielded spectrum. The shifts in the cadmium shielded spectrum agreed with data trend predictions from many surveillance and accelerated irradiations where thermal dpa doses were small. The influence of thermal neutrons was incorporated into trend curves by using an “effective” dpa dose, i.e. dpaeffective= dpafast + k dpathermal where k is a thermal neutron efficiency factor. For doses <300 × 10-5dpathermal the value of k was 2.0 ± 0.5. In a C-Mn steel containing an increased level of impurity boron, an allowance was required for the additional dpa generated by the thermal neutron-induced transmutation of boron-10. For thermal doses where the burn-out of boron-10 was not too great, the value of k in the embrittlement equation increased to 2.0 + 0.3(B-1) ± 0.5 for steels containing B weight ppm of natural boron. For a high copper C-Mn-Mo steel, hardening and embrittlement shifts arose due to irradiation-enhanced copper precipitation. Over the thermal dose range examined, thermal neutrons did not change the dose dependence of copper precipitation hardening.
Analysis of Stress-Induced Burgers Vector Anisotropy in Pressurized Tube Specimens of Irradiated Ferritic-Martensitic Steels: JFMS and JLF-1
Authors: Gelles DS , Kimura A , Shibayama T
Published: April 2008

A procedure for determining the Burgers vector anisotropy in irradiated ferritic steels is described, allowing identification of all a ⟨ 100 ⟩ and all a/2 ⟨ 111 ⟩ dislocations in a region of interest. The necessary micrographs to apply the procedure have been taken of a pressurized tube specimen of JFMS, a duplex ferritic steel following irradiation in FFTF/MOTA at 407°C to 7.5 × 1022 n/cm2 (E > 0.1 MeV) or 37.5 dpa, and a pressurized tube of JLF-1 irradiated at 430°C under similar conditions to 14.3 × 1022 n/cm2 (E > 0.1 MeV) or 60 dpa. Analysis of micrographs indicates that large anisotropy in Burgers vector populations develop during irradiation creep.
An Evaluation of Neutron Energy Spectrum Effects in Iron Based on Molecular Dynamics Displacement Cascade Simulations
Authors: Stoller RE , Greenwood LR
Published: April 2008

The results of molecular dynamics (MD) displacement cascade simulations in bcc iron have been used to obtain effective cross sections for two measures of primary damage production: (1) the number of surviving point defects expressed as a fraction of the displacements calculated using the standard secondary displacement model of Norgett, Robinson, and Torrens (NRT), and (2) the fraction of the surviving interstitials contained in clusters that formed during the cascade event. Primary knockon atom spectra for iron obtained from the SPECTER code have been used to weight these MD-based damage production cross sections in order to obtain spectrally-averaged values for several locations in commercial fission reactors and materials test reactors. An evaluation of these results indicates that neutron energy spectrum differences between the various environments do not lead to significant differences between the average primary damage formation parameters. In particular, the defect production cross sections obtained for PWR and BWR neutron spectra were not significantly different. The variation of the defect production cross sections as a function of depth into the reactor pressure vessel wall is used as a sample application of the cross sections. A slight difference between the attenuation behavior of the PWR and BWR was noted; this difference could be explained by a subtle difference in the energy dependence of the neutron spectra. Overall, the simulations support the continued use of dpa as a damage correlation parameter.
In-Reactor Creep Regularities of Copper
Authors: Aitkhozhin ES , Pyatiletov YS , Chumakov EV
Published: April 2008

The systematic research of in-reactor creep regularities for different purity polycrystalline copper and elaboration of the related theoretical model are discussed. The stress and temperature dependence of the in-reactor and thermal creep rates of pure copper and temperature dependence of the in-reactor and thermal creep rates of technical copper have been analyzed. It is shown that for each of the materials studied there is a temperature region where an abnormal reduction of the creep rate with increasing temperature takes place. A creep model based on dislocations sliding and thermoactivation overcoming of barriers by them is suggested. It is shown that the model well describes the conduct peculiarities of the in-reactor and thermal creep rates of copper in different temperature-strength conditions. The reasons for the abnormal temperature dependence of the creep rate in the intermediate temperature region are discussed.