bluuebunny/crossref_metadata_2025 huggingface dataset:
Good Laboratory Practice in the Creep Testing of Geosynthetics
Authors: Greenwood JH , Palmer JM
Published: April 2008

Ten years ago the coefficient of variation of creep test measurements in our laboratory was reported as being 8.6% to 12%. Now it is between 1.0 and 1.6%. This paper reports on the changes which have brought about this large improvement in accuracy.
Single-Wafer Gate Dielectric Technologies for Sub-0.18 μm Applications
Authors: Miner G , Xing G , Yokota Y , Jaggi A , Sanchez E , Chen C , Lopes D
Published: April 2008

The continued aggressive scaling of device dimensions presents serious challenges in transistor design and process integration. In particular for the gate dielectric, the reduction in equivalent oxide thickness challenges the limits of current process and equipment technologies. Single-wafer oxidation technologies are fundamentally different from their batch furnace counterparts and can address these challenges. The differences in single-wafer reaction chemistry are responsible for significant improvements in gate dielectric integrity. Rapid thermal processing also makes possible high levels of nitrogen incorporation, while maintaining this reliability improvement. These improvements will be increasingly important for the next several device generations.
Qualification of Epi Layers and Interface Properties by an Improved μ-PCD Technique
Authors: Pavelka T
Published: April 2008

The microwave photoconductive decay (μ-PCD) and the surface photo voltage (SPV) techniques are proved to be powerful methods in the qualification of semiconductor bulk materials. They are applied best for standard wafers with homogeneous material quality. However, both methods have their limitations when measuring epitaxial layer (epi) wafers or silicon on insulator (SOI) structures. In its conventional realization the SPV measurement is limited by the active layer thickness. On the other hand an epi layer grown on highly doped substrate typically does not generate high enough signal in a μ-PCD measurement.

The aim of the present work is the introduction of a new, improved microwave photoconductive decay technique with sensitivity exceeding that of the conventional techniques by orders of magnitude. It is shown that such a method is not only able to provide material quality in case of epi and SOI structures but can help also in the qualification of interface properties.

Data are presented to show the above statement including maps of contamination distributions in epi structures.
Biaxial Strength Testing of Isotropic and Anisotropic Monoliths
Authors: Salem JA , Jenkins MG
Published: April 2008

A test apparatus for measuring the multiaxial strength of circular plates was developed and experimentally verified. Contact and frictional stresses were avoided in the highly stressed regions of the test specimen by using fluid pressurization to load the specimen. Both isotropic plates and single crystal NiAl plates were considered, and the necessary strain functions for anisotropic plates were formulated. For isotropic plates and single-crystal NiAl plates, the maximum stresses generated in the test rig were within 2% of those calculated by plate theory when the support ring was lubricated.
In-Plane Biaxial Failure Surface of Cold-Rolled 304 Stainless Steel Sheets
Authors: Covey SJ , Bartolotta PA
Published: April 2008

Cold forming of thin metallic plates and sheets is a common inexpensive manufacturing process for many thin lightweight components. Unfortunately, part rejection rates of cold (or warm) rolled sheet metals are high. This is especially true for materials that have a texture (i.e., cold-rolled stainless steel sheets) and are being cold-formed into geometrically complex parts. To obtain an understanding on how cold forming affects behavior and subsequent high rejection rates, a series of in-plane biaxial tests was conducted on thin 0.1-mm (0.004-in.) fully cold-rolled 304 stainless steel sheets. The sheets were tested using an in-plane biaxial test system with acoustic emission. A failure surface was mapped out for the 304 stainless steel sheet. Results from this study indicated that an angle of 72° from the transverse orientation for the peak strain direction during forming should be avoided. This was microstructurally related to the length-to-width ratio of the elongated 304 stainless steel grains. Thus on rejected parts, it is expected that a high number of cracks will be located in the plastic deformation regions of cold-formed details with the same orientation.
Axial-Torsional Load Effects of Haynes 188 at 650°C
Authors: Lissenden CJ , Walker MA , Lerch BA
Published: April 2008

Threshold and flow loci were constructed experimentally at 650°C in the axial-shear stress plane for the cobalt-based alloy Haynes 188. These loci suggest that the stress-dependence of the dissipation potential is on the second deviatoric stress invariant, J2, alone. The functional form of the dissipation is critical to associative potential-based viscoplasticity models because it dictates the direction of the inelastic strain rate vector through normality. The directions of the inelastic strain rate vectors for proportional loading were in generally good agreement with the normality rule. Data suitable for characterizing the material parameters of a viscoplasticity model are presented. Serrated yielding was often present for axial, torsional, and combined axial-torsional loading. By applying proportional and nonproportional load histories at identical equivalent strain rates, J2 was found to generally reduce the data to a single curve.
Generalization of Energy-Based Multiaxial Fatigue Criteria to Random Loading
Authors: Łagoda T , Macha E
Published: April 2008

Results from a review of energy-based criteria of multiaxial fatigue indicate that they may be divided into three groups, depending on the kind of strain energy density per cycle which is assumed as a damage parameter. They are: criteria based on elastic strain energy for high-cycle fatigue, criteria based on plastic strain energy for low-cycle fatigue, and criteria based on the sum of plastic and elastic strain energies for both low- and high-cycle fatigue.

Lately, special attention has been paid to criteria taking into account strain energy density on the critical plane. However, in the energy approach to multiaxial fatigue there is an important unsolved problem, namely, the evaluation of energy, especially plastic strain energy density, from the closed stress-strain hysteresis loops under random loading.

In this paper, energy parameters defined for random loading are introduced. Under uniaxial loading we distinguish between the strain energy density for tension (positive) and the strain energy density for compression (negative). As a consequence, if there is no mean component in the random loading, we obtain a random history of strain (elastic and plastic) energy density with a mean of zero. Next, some known energy criteria of multiaxial cyclic fatigue were generalized for the random loading.

The new criterion has been successfully used for fatigue life calculation under uniaxial and biaxial random tension-compression of plane specimens made of 10HNAP steel. For this material the equivalent strain energy density on the critical plane, Weq (t), seems to be an efficient parameter under non-proportional random loading in the range of a great number of cycles. The equivalent strain energy density is derived from the new criterion.
Fatigue of the Quenched and Tempered Steel 42CrMo4 (SAE 4140) under Combined In- and Out-of-Phase Tension and Torsion
Authors: Löwisch G , Bomas H , Mayr P
Published: April 2008

Two types of specimens of the quenched and hardened steel 42CrMo4 (similar to SAE 4140) that differed in their residual stress state were tested by combined tension-torsion in- and out-of-phase loading. Under cyclic, stress controlled loading an elastic behavior is registered until 50% of the lifetime. Then a continuous softening occurs, the velocity of which correlates with the von-Mises equivalent stress in the case of in-phase loading. The residual stresses have no influence on the lifetime when cyclic softening occurs. Analytically, the lifetime is best described by the fatigue criterion of Zenner which considers the integral average of the stress state in every plane. This stress state is described by a function of the shear stress amplitude and the normal stress amplitude. Below the cyclic yield strength, the residual stresses must be taken into account as static stresses. The comparison of the local residual stress distributions is possible by using the weakest link model of Heckel.
An In-Plane Biaxial Contact Extensometer
Authors: Krause DL , Bartolotta PA
Published: April 2008

A new extensometer system was developed to measure strains in cruciform specimens under in-plane biaxial loading at elevated temperature. This system incorporates standard axial contact extensometers to provide a cost-effective high-precision instrument. Capabilities include a minimum strain range of 25% and a maximum sensitivity of eight microstrain (μm/m). Allowable environments include elevated temperature, presently tested to 600°C, and pressures from atmospheric to high vacuum. Descriptions of the test facility, modifications, mounting components, and installation procedures are reported. Calibration of the extensometers is described, including setup, error determination, and classification. Test results are presented for a stainless steel specimen. Strain gage and extensometer outputs are compared for static load cases and for combinations of waveform shape, strain range, frequency range, and test duration for cyclic room temperature tests. Elevated temperature results are presented for free thermal growth conditions and for instrument stability during hot cyclic operation. The results are summarized by the following: the new extensometer system calibrated with a maximum error of 0.8%; room temperature correlation with strain gage data yielded an average variation of 58 μm/m; operation under cyclic conditions resulted in tracking errors less than 3%; elevated temperature results compared accurately with theoretical predictions; and, long duration testing proved to be stable.
Cruciform Specimens for In-Plane Biaxial Fracture, Deformation, and Fatigue Testing
Authors: Dalle Donne C , Trautmann K-H , Amstutz H
Published: April 2008

Three different types of cruciform specimens, which have been used successfully on the DLR biaxial test rig for investigations in the fields of fracture mechanics, yield surface evaluation, and fatigue of riveted joints are presented in detail. The following three characteristics were required from these specimens: a uniform stress and strain distribution in the central testing regions, low manufacturing costs, and easy mounting in the DLR biaxial test rig. It is shown that the first and the second requirement are in conflict. Because of the uneven stress distribution in the simple and inexpensive fracture mechanics specimen, additional finite-element calculations were needed for a full fracture mechanical characterization. On the other hand, impelling a very uniform stress distribution in the riveted cruciform specimens increased the manufacturing costs considerably. The specimen which satisfies the demands best is the yield locus evaluation specimen of deep drawing steel. It has low manufacturing costs and a very uniform strain distribution in the central testing section.
Assessing Life Prediction Methodologies for Fasteners Under Bending Loads
Authors: Counts W , Johnson WS , Jin O
Published: April 2008

New polyimide matrix composite materials are leading candidates for aerospace structural applications due to their high strength to weight ratio and excellent mechanical properties at elevated temperatures. The high fatigue resistance of these composites often results in the bolts being the weak link of a structure. Aircraft-quality bolts made of 4340 steel with a minimum UTS = 1241 MPa (180 ksi) were tested in three-point bend fatigue. Two life prediction methodologies were accessed for bending stress: S-N curves and fracture mechanics. The tensile S-N curve from the Mil-Handbook-5 conservatively predicts the bending fatigue life and run-out stress. Crack growth data, in the form of da / dN versus ΔK, from the Damage Tolerant Design Handbook was converted to a versus N data using five geometric correction factors. None of the five correction factors accurately predict crack growth, but all five correction factors did conservatively predict crack growth.
Failure Analysis of High Strength Steel Army Tank Recoil Mechanism Bolts
Authors: Champagne VK
Published: April 2008

A failure analysis of two broken bolts from an Army tank recoil mechanism was performed by the U.S. Army Research Laboratory (ARL), Weapons and Materials Research Directorate. The bolts failed at the head-to-shank radius during installation at Aniston Army Depot. A total of 69 additional bolts from inventory and the field were also characterized and tested for comparison. Optical and electron microscopy of the broken bolts showed topographies and black oxide on the fracture surface consistent with the characteristics of quench cracks. The crack origin was located within a region covered with a heavy black oxide where fracture occurred as a result of intergranular decohesion. Heat treatment tests of the material confirmed the black oxide to be formed during the tempering operation of ∼677°C. The remaining fracture surface failed in a ductile fashion. The cause of failure was attributed to preexisting quench cracks which should have been detected by the required 100% magnetic particle inspection conducted during manufacturing. These cracks propagated during installation, causing the bolt heads to sever. Recommendations were provided to screen inventory to prevent cracked parts from entering fielded tanks and improve control of manufacturing and inspection procedures. These included machining the head-to-shank radii to specification, tighter control of the magnetic particle inspection process, the use of dull cadmium plate to mitigate the potential for delayed failures due to hydrogen embrittlement or stress corrosion cracking, an alternative to electrolytic cadmium plate (such as vacuum deposition), and finally, replacing all existing bolts in the field and in inventory with new or reinspected bolts.
Residual Strength Assessment of Stress Corrosion in High Strength Steel Components
Authors: Barke D , Chiu WK , Fernando S
Published: April 2008

Testing of finished high strength steel components for their susceptibility or resistance to stress corrosion cracking (SCC) provides data of immense value to designers and manufacturers. Reported in the literature are many different techniques of testing for SCC which have varying advantages and disadvantages. However, most techniques have been questioned on the grounds of applicability and reproducibility.

A test which rapidly ranks similar components, in order of resistance to SCC, is in demand. Techniques which quantify the extent of damage, after a period of time, such as the breaking load method, are able to overcome some of the limitations of other SCC tests. The use of the breaking load method has been reported to provide reliable results in the comparison of certain aluminum alloys.

This paper applies the breaking load method, a residual strength test, to high strength steel components. Bolts, rather than tensile test specimens, were used, to enable the effect of geometry and manufacturing methods on susceptibility to SCC to be studied. It is concluded that the breaking load method can be used to rank differences between materials, manufacturing methods and geometry.
Stress Intensity Factor Solutions for Fasteners in NASGRO 3.0
Authors: Mettu SR , de Koning AU , Lof CJ , Schra L , McMahon JJ , Forman RG
Published: April 2008

Fasteners are widely used in aerospace and other industrial applications. Structural integrity analysis of such components is a critical necessity in many of the applications. The present paper describes some recently obtained stress intensity factor solutions for cracked threaded members and for cracked fillet areas under bolt heads. The cracks were assumed to be thumb-nail shaped and to originate at the thread roots or fillet radii. The assumed aspect ratios were based on observed shapes from crack growth tests. The tests were conducted on A286 steel, Ti-6Al-4V titanium alloy and 7075-T73 aluminum alloy. Crack growth was measured using marker bands that result from changing the load level after a certain number of cycles. The measured crack growth rates were converted to stress intensity factors using certain principles of similitude. Three-dimensional finite elements were used to verify the solutions. Finite-element analysis was also used to compute the stress concentration factors at the thread roots and fillets. A distinction was made between rolled and cut threads. In the case of rolled threads or fillets, the residual stresses cause a reduction of the stress intensity factor for small cracks. In the case of machined threads or fillets, the stress concentration factor at the thread or fillet root governs the magnitude of the stress intensity factor. Specific solutions were constructed and coded in for standard aerospace bolt sizes, but provision was made for other sizes that may be applicable for general industrial use. The solutions are valid for metric as well as for U.S. customary sizes. These solutions were developed for implementation into the NAS-GRO 3.0 software. NASGRO is a state-of-the-art software package for fatigue crack growth and fracture mechanics analysis.
Experimental Techniques to Evaluate Fatigue Crack Growth in Preflawed Bolts Under Tensile Loads
Authors: Dawson CB , Thomsen ML
Published: April 2008

Fatigue crack growth testing of Inconel and multiphase 159 bolts is presented. The direct-current potential difference technique is shown to be successful in obtaining crack length data from the test bolts with short grip lengths. Three stress intensity solutions for round sections are presented with a preferred solution suggested. This preference is based on the ability to apply a geometric correction that is variable with crack depth and crack aspect ratio. The crack aspect ratio functionality was determined experimentally by ”marker banding” the fracture surface and adjusting the stress intensity solution, following the test, by adjusting the crack aspect ratio. The fatigue crack growth of the Inconel was completely successful. The MP159 cracking was initially Mode I but quickly turned mixed mode, thus invalidating the Mode I crack growth data.
Nondestructive Evaluation of Dimension Stone Using Impulse-Generated Stress Waves: Part 2—Estimation of Complex Moduli
Authors: dos Reis HLM , Habboub AK
Published: April 2008

Using principles of Statistical Energy Analysis, a nondestructive evaluation methodology is presented to estimate the average Poisson's ratio and the average dynamic complex bulk, shear, extensional, and longitudinal moduli of dimension stone. The estimated moduli represent an average over the volume of the test specimen and over a frequency band up to 200 kHz. The proposed methodology is based upon the energy-density decay function of an impact-generated diffuse wave field using small dynamic strain amplitudes. Invoking the principles of linear viscoelasticity, various loss parameters are also extracted and discussed. The methodology allows the evaluation of the energy dissipation characteristics of different stone types, and their dependence upon the stone microstructure.
Assessment of the Durability of Porous Limestones: Specification and Interpretation of Test Data in UK Practice
Authors: Miglio BF , Richardson DM , Yates TS , West D
Published: April 2008

This paper discusses the methods currently used in the UK to evaluate the durability of limestones when used as stone cladding. This review is combined with an analysis of the data obtained in a study of all commercially available UK building limestones and provides advice concerning the use of various test properties as a guide to durability. Within this review, recommendations demonstrating how these tests may be specified in UK practice are also given.
Natural Weathering of Granite: A Case Study
Authors: Scheffler MJ , Lesak JD
Published: April 2008

Over the past few decades, natural stone granite claddings have become very widely used. The long-term weathering behavior of granite has been less studied than that of other natural stones, such as marble, that were more extensively used in the past and have experienced notable weathering related problems when used as an exterior veneer cladding in certain climates.

A white domestic granite, in place for more than 80 years and exposed to a northern midwestern climate, was studied to determine the cause of weather-related surface deterioration. The exterior walls of this monumental building, constructed of granite blocks mostly more than 200 mm (8 inches) thick experienced weathering distress including surface sugaring (saccarification), exfoliation, spalling, and discoloration. A loss of as much as 3 mm (1/8 inch) of granite from the bush-hammer surface of units was documented. The surface deterioration has had no apparent structural effect on the 200 mm thick units. However, similar deterioration, if it were to occur on 20 to 30 mm-thick veneer cladding, made of this material, would have a significant structural, as well as aesthetic impact. The major impact on the stone in this study was aesthetic. The weathering deterioration caused the stone surface color to alter and become irregular. The stone surface, which was originally uniformly light gray to white, became blotchy, ranging in color from white to dark gray.

Studies of the deteriorated granite included documentation of the extent and various types of distress present, as well as laboratory studies of removed distressed and intact samples. The effects that weathering exposure have on the degree of deterioration and overall aesthetic impact were explored. Scanning electron microscope studies, petrographic analysis, and x-ray diffraction analysis were also performed.

This paper presents the results of the studies performed to determine the chemical cause of the deterioration observed and provides a basis for understanding the fundamental causes of natural weathering of this granite. Also presented are the results of various treatment methods that were evaluated to determine if there is an effective means of restoring or providing a more uniform granite finish.
Review of Durability Testing in the United States and Europe
Authors: Bortz SA , Wonneberger B
Published: April 2008

There are criticisms that durability (accelerated weathering) test procedures have no relationship to natural weathering. The fact is that stone can vary from quarry to quarry, within a single quarry, and within a single quarry block. Therefore, it is important to test the specific supply of stone for a large building project. Stone used successfully on a similar project in the past may not have the same physical or mechanical properties for a current project. Durability testing can provide comparative information that can determine stones that are more susceptible to erosion or deterioration from natural weathering.

The purpose of this paper is to review various durability test procedures used in Europe and the United States. The Europeans are exploring separate test procedures which are appropriate for specific types of stones, while the Americans in the United States are studying a single test method that can be carried out to a standard procedure. The European systems rely on saturation coefficient and porosity, while some utilize a freeze-thaw test. The British have also studied separate test procedures that are specific for limestone, sandstone, slate, granite and marble. The French and Belgians have attempted to relate compression, capillary coefficient, sonic modulus testing and wear resistance to durability. There is wide diversity between the durability test procedures preferred by the French and Belgians then preferred by the British. The Americans rely to a great extent on freeze-thaw testing to determine durability. At present, the Americans have published more data than the Europeans regarding comparisons between durability testing and natural weathering. Based on the analysis in this paper, it may be possible to find a common thread for the development of a standard test for all stones or separate tests for individual types of stone.
In-Place Load Testing of a Stone Cladding Anchorage System
Authors: Scavuzzo R , Acri J
Published: April 2008

Proper evaluation, simulation, and subsequent testing of the forces acting on a stone cladding anchorage system are critical elements in the overall success of the anchorage system design as it relates to serviceability, safety, durability, and aesthetics. In some cases, to accurately predict anchorage performance, the stone cladding system must be tested as a whole under service loading conditions to observe the total deflection of the entire anchorage system assembly, including anchors, studs, flashing, drywall, toggles, mounting screws, etc. Presented is a case study which incorporated in-place testing to simulate the combined dead load and wind load forces acting on a penthouse level mechanical screen wall on a multi-story building in the Denver-Metro area. Testing on a series of stone cladding anchorage systems was performed to help determine if design deflection criteria could be achieved.
Mechanisms of Atmospheric Corrosion in Tropical Environments
Authors: Cole IS
Published: April 2008

The paper presents results from a five-nation (Australia, Indonesia, the Philippines, Thailand, and Indonesia) study into the relationship between climatic/pollutant factors and corrosion of zinc and mild steel. While a good correlation was found between the corrosion rate of mild steel and gaseous SO2 and rainwater pH, no such relationship was found between these parameters and the corrosion rate of zinc. This observation has prompted an investigation into the forms of pollutant deposition. Particulate deposition, gaseous absorption into moisture layers on metal surfaces, and deposition in fine and coarse raindrops are discussed. The discussion focuses on the rate of each process and the chemistry of the moisture formed on metal surfaces as a result of the processes. A chemical reaction simulator is used to model the changing chemistry of moisture layers under a number of environmental scenarios. These scenarios highlight the importance of the ratio of the gaseous NH3/SO2 and of oxidation of S(IV) in controlling both the acidity and composition of moisture films. The relevance of these processes to the rates of corrosion is discussed, and some hypothesis for the low corrosion rate of zinc in the five-nation study is presented.
Electrical Conductivity of Concrete and Mortar Prepared with Calcareous Aggregates for Construction in the Gulf of Mexico
Authors: Maldonado L
Published: April 2008

The electrical conductivity of mortar and concrete samples was measured. Series of samples were prepared with crushed limestone (approximately 95–98% calcium carbonate), water-to-cement ratios of 0.53, 0.59, 0.70 and 0.76 and cured at 7 and 28 days. The conductivity, for both mortar and concrete, in chloride solution of concentration 1M, 2M, 3M and 4M, increases as the chloride concentration in the solution increases. The conductivity of mortar specimens take values between 0.60 and 2.18 mS/cm, while the concrete samples have values in the range from 2.10 to 5.44 mS/cm. For concrete samples, the conductivity decreases with curing time, which indicates that the conduction is, in such a case, due mainly to capillar porosity. The conductivity values of mortar increase, when the curing time increases. It is suggested that such behavior is due to the hydration process of the paste in the mortar and the water transport in the pore gel structure resulting thereafter.
Time of Wetness and Temperature as Tools to Evaluate Corrosion Risk in Concrete Blocks Exposed to a Humid Tropical Environment
Authors: Castro P , Véleva LP
Published: April 2008

The internal relative humidity (RH) during the setting, curing and service life is one of the factors that influences on the durability of any concrete structure. However, it does not show evidence of rebar deterioration since local corrosion products formed change the critical RH value. For this reason, the measurements of the RH in concrete, as many authors have stated in the literature, are not accurate enough to predict the development of the corrosion process. The time of wetness (TOW) and the moisture content are, however, more acceptable parameters to survey the structure durability. This paper discusses the information that the concrete internal temperature (T) and the TOW provide regarding durability, when changes in the external environmental parameters, the geometry of the structure and its orientation with respect to the sun take place. The monitored data are from concrete exposed to humid tropical atmosphere of Yucatan Peninsula, southeast of Mexico. Some of the results indicated that there are specific tendencies regarding geometry and orientation of the specimens. The TOW distribution found in this work would allow the structure designers to define the concrete thickness over the steel bars based on the orientation and geometry of the structural element and in terms of the direction in which the environmental parameters act.
Design and Protection Criteria for Cathodic Protection of Seawater Intake Structures in Petrochemical Plants
Authors: Chaudhary Z
Published: April 2008

Impressed current cathodic protection (ICCP) and sacrificial anode cathodic protection (SACP) systems were designed and installed to control chloride-induced corrosion of the steel reinforcement in the atmospherically exposed and submerged parts of the seawater structures, respectively. The design and long-term performance assessment of these systems are described and discussed. The monitoring data collected have suggested that all ICCP systems are performing satisfactorily and meeting the design objectives in controlling the corrosion of the steel reinforcement. The SACP systems generally did not meet the specified criterion of -800 mV Ag/AgCl current-on steel potentials; however, there have been no signs of corrosion or concrete distress in submerged areas since application of SACP system.

The results showed that a steel current density ranging between 8 and 14 mA/m2 was sufficient to afford required protection to the steel reinforcement in different structures. The protection afforded to these structures has residual effect and could last up to 2 months or so when the CP system is turned off. As a result of CP application, the corrosion potentials of the steel reinforcement have been shifted by some 100 to 200 mV in the positive direction.
Methodology for Service Life Prediction of Stainless Steel Reinforced Structures Based on the Correlation between Electrochemical and Mechanical Manifestations of Corrosion
Authors: Tula L , Helene PRL
Published: April 2008

The use of stainless steel reinforcement is recommended for structures exposed to chloride contamination. Concrete structures reinforced with stainless steel are more durable than common carbon steel reinforced structures. In some projects, service lives of 120 and 200 years have been projected. Long-term field experience, which confirms these predictions, is not available. It would be very useful to obtain an acceptable approach to service life prediction. This paper proposes a methodology using the integration of electrochemical and mechanical behavior of the stainless steel rebar corroding in accelerated tests. The studied material is a 10 mm diameter 316L stainless steel bar. The carbon steel bar was included as part of the comparative performance study. The first part of the study analyzes corrosion potential data and potentiodynamic curves. The other part of the study is dedicated to the physical-mechanical consequences of the corrosion in the bars: the bond and tensile strength losses. Integrating both parts of the study and with the aid of some models allowed an approach to the service life prediction of structures reinforced with stainless steel rebars. Some questions for future work are presented.
An Evaluation of Fungal-Influenced Corrosion of Aircraft Operating in Marine Tropical Environments
Authors: Little BJ , Pope RK , Ray RI
Published: April 2008

Fungi were isolated and identified in ten aircraft that had been operating in marine tropical environments. Distribution and growth of fungi depended on availability of water and nutrients. Laboratory experiments demonstrated that surface washes, including the approved military maintenance procedure, were ineffective in removing fungal hyphae embedded in polyurethane coatings. Surface cleaning removed spores and discoloration associated with fungi, but fragments of the hyphae remained and grew as soon as conditions were favorable. Aged coatings fouled more rapidly than new coatings. Fungicides incorporated into the topcoats produced mixed results. Bare aluminum suffered localized corrosion when colonized by fungi.
Use of Coatings to Assess the Crevice Corrosion Resistance of Stainless Steels in Warm Seawater
Authors: Kain RM
Published: April 2008

This paper focuses on the utility of epoxy-type coatings for testing the crevice corrosion resistance of a variety of stainless type alloys in warm, natural seawater. Details of surface preparation, coating application and exposure to 30°C seawater for periods of up to six months are provided. Testing comprised exposure of UNS S31603, UNS N08367 and UNS S20910 in one or more of the following forms: pipe, sheet, welded plate. Results are discussed in terms of alloy resistance to crevice corrosion initiation and propagation. The attributes of coatings as a crevice former are reviewed. While alloy N08367 was clearly the most resistant to crevice corrosion initiation at coating sites, it suffered intense attack in some cases.
Developments in Reactor Dosimetry in Japan
Authors: Kimura I
Published: April 2008

Recent activities in reactor dosimetry developments in Japan are reviewed. First, those of research, test and prototype reactors are shown. Next, the present status of surveillance testing in light water reactors is outlined, and several experimental topics are introduced. Then the dosimetry cross section data are described. Finally, future trends in reactor dosimetry are discussed.
Overview of the Surveillance Dosimetry Activities in Ukraine
Authors: Bukanov VN , Dyemokhin VL , Gavriljuk VI , Grytsenko OV , Nedyelin OV , Vasylyeva EG
Published: April 2008

Calculational-experimental methodology is used for radiation exposure determination of WWER-1000 reactor pressure vessels operating in Ukraine. It includes numerical neutron transport calculations within reactor near-vessel space and ex-vessel dosimetry measurements at operating units. Fluxes, spectra and neutron fluences with En>0.5 MeV onto surveillance specimens of WWER-1000 reactor pressure vessel metal are determined by calculations. Program packages DETA and MCSS are designed in the Scientific Center “Institute for Nuclear Research” for the neutron transport calculations within reactor near-vessel space and at the locations of surveillance specimens in WWER-1000 reactor. Maximal neutron fluences onto the upper shell base metal of Khmelnitskaya Nuclear Power Plant (NPP) Unit 1 reactor pressure vessel are determined over the first ten fuel cycles. A number of irradiation parameters for surveillance specimens of first and second control term of Khmelnitskaya NPP Unit 1 and South-Ukrainian NPP Unit 3 reactor pressure vessel metal are calculated.
Neutron Dosimetry for VVER Reactor Pressure Vessels in the Czech Republic
Authors: Brumovsky M , Erben O , Hogel J , Osmera B
Published: April 2008

The paper gives a description of the contemporary methods used for the fast neutron fluence determination applied to the reactors of the Dukovany VVER-440 nuclear power plant (NPP). Measurement methods include measurements in containers with supplementary surveillance program and in the reactor cavity. Retrospective dosimetry using scraps of reactor pressure vessel cladding material is being prepared. Information is also given about the analogous methods prepared for the reactors of the Temelin VVER-1000 NPP. The results at measured points (reactor cavity, surveillance) are recalculated to the reactor pressure vessel inner wall by using the conversion factors obtained in mock-up experiments carried out for both VVER- 440 and VVER-1000 at the LR-0 research reactor. The experimental works are completed with fluence calculations for which two methods have been developed. The DAVKA code is the LEPRICON system adaptation for the VVER reactors and the INCAL 3D code makes use of the influence functions of the given volume of the fuel element to the total fluence. Measurements can be completed by gamma scanning of surveillance specimens rest activities.
Analysis of Pressure Vessel Surveillance Dosimetry Inserted into Korean PWR
Authors: Gil C-S , Kim J-D , Chang J
Published: April 2008

A new neutron-gamma coupled MATXS-format library, which is designated KASHIL-E6, has been generated for shielding or reactor pressure vessel dosimetry applications. The library was tested against the NESDIP-2 experiment for application to the RPV dosimetry. Dosimetry analyses on the surveillance capsules of the Ulchin Unit 1 have been carried out using KASHIL-E6. The analyzed dosimeter reactions are 54Fe(n,p), 58Ni(n,p), and 63Cu(n,α) at the end of 3rd, 6th, and 8th fuel cycle of the power plant. To demonstrate the differences of dosimetry data in the current evaluated data files, the data from five different files were examined. The calculations for the benchmarks agree with the measurements within 10%. The calculated values of 54Fe(n,p) and 58Ni(n,p) in the surveillance capsules show differences of 10% from the measurements while those of 63Cu(n,α) are over 20%. Maximum difference on 54Fe(n,p) between JENDL-3.2 and JEF-2.2 is 20%.
The Attenuation of Neutron Dose Rates through the Steel Pressure Vessels of Magnox Power Plants
Authors: Fletcher AL , Mossop JR , Page CJ
Published: April 2008

This paper describes the calculation of the attenuation of neutron dose through the steel pressure vessels of Magnox power plant operated by BNFL, Magnox Generation Division. These data are required for the assessment of the structural integrity of the plant.

Detailed three-dimensional neutron transport models of the reactors, pressure vessels and surrounding bioshields have been developed using the AEA Technology Monte-Carlo code MCBEND. These have been used to calculate neutron fluxes through the pressure vessel in both sub-core and side-core regions of pressure vessels, the two bounding extremes of the incident neutron spectra. The effect of postulated cracks in the RPV is shown not to influence the predicted neutron doses.

A comparison with neutron fluxes measured from through wall samples removed from a decommissioned reactor show the calculation route to be accurate.
Use of SSTRs and a Multi-Component Shield Assembly to Measure Radiation Penetrating the Reactor Biological Shield in the Presence of Radiation Streaming from Other Sources
Authors: Fero AH
Published: April 2008

This paper describes the results of neutron transport calculations and measurements that were performed for the concrete biological shield that surrounds a Westinghouse two-loop reactor. As a concrete shield ages a number of changes occur. Foremost among these, from a radiation shielding perspective, is the loss of water. The measurement of the neutron dose rate is a sensitive indicator of change in the biological shield concrete. For example, a 50% reduction in the water content of the shield as the result of age-related water loss results in a factor of 22 increase in the neutron dose rate but only a factor of three increase in the gamma ray dose rate. The measurements described herein employ solid state track recorders (SSTRs) and a multi-component shield assembly to separate the transmitted and background radiation field components.
Comprehensive Nuclear Fuel Dosimetry Program in the OSIRIS Reactor
Authors: Alberman A , Morin C , Marchand L , Marcault A
Published: April 2008

The nuclear share of the total electricity generation in France is close to 75%. The operating flexibility of the power plants is conditioned in particular by the ability of the fuel elements to withstand operating regimes with load follow and without clad failure. The operator's consideration of margin criteria for pellet/clad interaction (PCI) led to a request to the CEA to conduct a power ramp tests program in a qualified and reliable facility.

Ramp tests for PWR fuel in France are carried out in the ISABELLE loop of the OSIRIS reactor at Saclay. Although extensive work has been performed to establish relevant thermal balance corrections (i.e., heat losses), the search for low uncertainties during the ramp experiments made it necessary to implement an extensive fuel dosimetry program. This program is based on a specific irradiation run involving nuclear, reactor physics, and radiochemical methods.

This paper describes the ISABELLE loop “qualification program:” fuel dosimetry in ISIS reactor (neutronic model of OSIRIS), gamma spectrometry and isotopic analysis, as well as energy deposition neutronic calculation. The outcome of this program was a sound determination of maximum fuel power and linear heat rate during each ramp test; accuracy was established at better than 6% (2α).
Improvement of Reactor Dosimetry for Irradiation Tests in the Experimental Fast Reactor JOYO
Authors: Sekine T , Aoyama T , Yoshida A , Suzuki S
Published: April 2008

Reactor dosimetry by the foil activation method and three dimensional diffusion or two dimensional transport calculation have been performed to characterize the neutron field of JOYO. In order to improve the accuracy of the neutron flux calculation for each irradiation test, the JOYO core management code system will be upgraded. In addition, a fine flux distribution inside the irradiation rig was analyzed by the Monte Carlo code. The helium accumulation method has been developed as a neutron fluence monitoring technique to be utilized for long-term irradiation tests. The system was calibrated in the well characterized fast neutron fields of YAYOI.
Database for WWER-1000 Reactor Pressure Vessel IAEA Regional Project RER 4/017
Authors: Ošmera B , Lyssakov V , Cvachovec F , Hudec F , Janský B , Mikuš J , Novák E , Pošta S , Turzík Z , Hort M , Krysl V , Smutný V , Zaritsky S , Alekseev N , Gurevitch M , Egorov A , Brodkin E , Ilieva K , Belousov S , Kovbasensko J , Uritani A , Misawa T , Mori C
Published: April 2008

A review of the results obtained in the framework of the Project is presented in the paper. The database consists of experimental data obtained in a model of WWER-1000 assembled in the LR-0 experimental reactor in NRI. The differential neutron spectra measurements were carried out over the water layer between the barrel simulator and reactor pressure vessel (RPV) simulator and over the RPV simulator thickness. The core power distribution was measured by means of gamma scanning of fuel elements (several hundreds of elements for the radial distribution and several tens for the axial one). The core power distribution calculations were done by MOBY DICK (2D several groups, diffusion code) and the Monte Carlo Code MCU—RFFI/A, the transport calculations were performed with deterministic codes in laboratories of the participating countries. The neutron spectra were compared in BUGLE 96 format.
Re-analysis of the Experimental Leakage Neutron Spectrum from a Silicon Spherical Shell with Incident 14 MeV Neutrons using Different and Modified Neutron Cross Section Libraries
Authors: Ichihara C , Hayashi SA , Kimura I , Yamamoto J , Takahashi A
Published: April 2008

In order to make benchmark validations of the nuclear data for fusion related materials, absolute leakage neutron from various spherical sample piles were measured earlier at OKTAVIAN. A detailed analysis for Si cross-section is presented here. A leakage neutron spectrum from a Si spherical pile of 60-cm diameter was compared with the calculated results obtained using MCNP-4A with different neutron data libraries. For a detailed study, trial calculations were also performed using modified JENDL-3.2 data libraries. It was found that ENDF/B-VI (release 5) gives the best predictions and the three JENDL data files and EFF-2.4 can predict the measured spectra fairly well. The prediction with FENDL-1.0 file differs by a large extent from the measured spectrum. The discrepancy found in the JENDL, EFF and FENDL calculations are likely to be due to the too low discrete inelastic scattering cross section and too large continuum inelastic cross section values of these libraries, respectively.
Monte Carlo Calculations of Neutron Fluence Spectra, Activation Measurements, Uncertainty Analysis and Spectrum Adjustment for the KORPUS Dosimetry Benchmark
Authors: Barz HU , Boehmer B , Konheiser J , Stephan I
Published: April 2008

The KORPUS irradiation experiment has been used to test and demonstrate improvements of the pressure vessel dosimetry methodology developed in Rossendorf. The Monte Carlo Code TRAMO has been recently supplied with extended geometries and with a new data treatment procedure for elastic scattering. The new code version has been used to accurately calculate absolute neutron fluence spectra at detector positions in the KORPUS irradiation facility at the RIAR in Dimitrovgrad. The sensitivity of the obtained fluences to various approximations in the calculations was investigated using calculations for different model variants.

The activation rates calculated with these spectra have been compared with results of activation measurements with detectors irradiated at the International Dosimetry Benchmark at the KORPUS facility. Based on the measured data the calculated fluence spectra have been adjusted with the help of the adjustment code system COSA3, a newly extended multi-spectrum version of COSA2. A comprehensive uncertainty analysis was accomplished for the fluence calculations and the measurements.
Actual and Potential Measurements of Fission-Rate Ratios in the NIST Iron Sphere
Authors: Perel RL , Wagschal JJ , Yeivin Y
Published: April 2008

We analyze various calculated fission-rate ratios in the leakage spectrum of the NIST iron sphere benchmark field employing a few modern cross-section libraries and compare the only measured value of the 237Np/238U ratio to the respective calculated values. We also present the sensitivities of the calculated fission rates and fission-rate ratios to the 56Fe elastic- and first-level-inelastic-scattering cross sections. We conclude with a recommendation of additional measurements that can shed more light on the various iron, in particular 56Fe, cross-section evaluations.
Analysis of the ORNL PCA Benchmark Using TORT and BUGLE-96
Authors: Fero AH , Anderson SL , Roberts GK
Published: April 2008

This paper describes the results of analyzing the ORNL PCA benchmark using TORT and the BUGLE-96 cross-section library. In particular, the analysis demonstrates the importance of using a three dimensional calculation to properly account for transverse leakage effects in a small mockup.