bluuebunny/crossref_metadata_2025 huggingface dataset:
Environmental Problems in Preserving Wooden Buildings at the Estonian Open Air Museum
Authors: Laht M
Published: April 2008

The Estonian Open Air Museum was founded in 1957 on the shore of Kopli Bay near Tallinn, on the territory of the 19th-century Rocca al Mare summer residence. By 1966, 22 structures had been transported to the Museum grounds. At present the number of structures is 79. The Museum was established to collect, preserve, study, and exhibit typical and best examples of historical rural architecture. Every component of the exposition, including ensembles of farm structures designed as villages together with their furnishings, are meant to recreate an authentic reflection of folk culture.

The Estonian Open Air Museum has encountered several problems in preserving its exhibit buildings. The geographical and climatic location of the Museum is not ideal for an open-air museum. Increased general pollution and acid precipitation have contributed to wood deterioration. It has proven difficult to adapt old wooden buildings to new environmental conditions into which they are transported.

The location of the Museum is rather unfavorable for preserving the exhibits. As the Estonian Open Air Museum is situated near the sea, a very damp maritime climate dominates. The first years of the Museum were accompanied by the lack of knowledge on how to control mold and fungi growth. The chemical treatment of exhibit buildings was begun in 1966. Structures in the Museum were treated periodically between 1966 and 1995. The increase of general pollution and the awareness of its effects has diminished the desire to continue to use chemicals in preserving the exhibit buildings.

At present, an alternative to chemicals is being utilized. Temperierungsystem, a German method for regulating the temperature in the buildings, diminishes the rate of humidity as well as the instability of temperature. It is too early, however, to pass judgement on the efficacy of this method.
The Restoration of Sodankylä Old Church 1992–1995
Authors: Kairamo M
Published: April 2008

In 1689 a wooden church was built in Lapland at Sodankylä. The building type, the horizontal log construction with block pillars, originates from the medieval times. Size of the church was 8.5 m × 13.5 m (28 ft × 44 ft), and the height, 8 m (26 ft). In 1778 the church was “modernized” by adding a wooden shingle roof and wooden panel cladding. Then, in 1859 the church was abandoned. In the 1920s a restoration was carried out by the National Board of Antiquities. In 1950 the roof was made of industrially sawn wooden shingles on bitumen felt. Some minor repairs took place in the 1950s, 1970, and 1985. The bitumen felt caused rotting of the shingles, and in 1972–95 a new wooden shingle roof and new wood panel were installed. The restoration principles considering authenticity were debated.

The work was financed mainly by the state employment program. It was done by traditional methods by hand. The shingles were carved by ax, the boards riven, handmade nails used and the bitumen felt was replaced by birch bark. Natural wood tar was used to protect the wood.

The total cost was about 2 million Fim (approximately $500,000). Knowledge of choosing, seasoning, working on and treating wood was gained during the building process.
The Maloney-Bridget Smith House: A Case Study in Preservation Philosophy
Authors: Foster JW
Published: April 2008

The preservation of a small, wooden miners cottage in New Jersey presents an opportunity to evaluate several important issues in historic preservation, including the role of a historic interpretive period versus the survival of the architectural fabric, and the merits of preserving the original fabric versus the replacement of elements to achieve an integrated whole.
Hydraulic Failure Analysis: Fluids, Components, and System Effects
Authors: Totten GE , Wills DK , Feldmann DG
Published: April 2008

Description

41 papers provide a comprehensive overview of the problems and new technologies in hydraulic systems associated with hydraulic fluids and their interaction with component design, component metallurgy, and the design of the hydraulic system itself.

Six sections cover: Theory, Mechanism and Simulation • Failure Analysis • Materials • Components--Seals, Valves and Rolling Element Bearings • Fluids

Major issues addressed include:

• The effect of fluid chemistry on component failure as the result of oxidation, wear debris, viscosity loss, generation of corrosion by-products, and yellow metal wear.

• Metallurgy of the material, including material pair effects and physical properties.

• The effect of surface finish.

• Modeling wear mechanisms as a function of material pair contact loading, speed, and other factors.

• Dynamic versus static wear.

• Wear mechanisms including rolling contact fatigue, cavitation, lubrication failure, abrasive wear, and others, in addition to combinations of these mechanisms.

• Methods of failure analysis focusing on strategies to identify root caused of failure.

• Hydraulic component design and metallurgy of bearings, gears, slippers, and end-plates.
Modeling the Ductile to Cleavage Transition in Steels and Structures
Authors: Howard IC , Li ZH , Sheikh MA
Published: April 2008

The process of ductile damage and subsequent crack growth and of cleavage in ferritic steels occur in steps whose controlling microstructural features are quite different. Useful models of these can, therefore, be attempted by associating the mechanisms of ductile damage or cleavage with an appropriate, microstructurally controlled, cell size. Furthermore, the cell size for ductile damage is typically too large to be used for the crack-tip finite elements that are required for accurate resolution of the large strain gradients in the continuum field that represents the deformation there prior to significant damage development. What is required is a finite-element code that allows (at least potentially) the presence of cells of more than one size.

These considerations have led to mesh-independent damage mechanics modeling, and a model of the ductile-to-brittle transition that has appropriate cell sizes for each failure mechanism. The complexity of these refined models demands very large computational times for technically interesting problems. Accordingly, our predictions of the outcome of engineering tests have used a compromise single-size cell model chosen to balance the conflicting requirements for each failure process. The paper describes the proving of this, and its use in predicting two of the large-scale spinning cylinder tests.

The work illustrates the potential conflict that may arise between the detailed accuracy required for rigorous physical representation and the pragmatism needed to capture the essentials of application-driven research programs. The paper ends with a discussion of the possible relations between these approaches and their areas of effectiveness.
Fatigue Crack Propagation and Load Interaction Effects in a Titanium Alloy
Authors: Lang M , Larsen JM
Published: April 2008

An experimental investigation of load interaction effects in Ti-6Al-2Sn-4Zn-2Mo is presented. Simple variable amplitude loading spectra were applied to test samples, and the crack propagation stress intensity factor, KPR, was subsequently measured. The data were condensed to two equations (“master curves”) that describe the influence of an unloading cycle after constant amplitude loading and a single overload cycle, respectively. The results suggest that load interaction effects are caused by residual compressive stresses ahead of the crack front, whereas the influence of crack closure is minor.
A New Multiparameter Model for the Prediction of Fatigue Crack Growth in Structural Metallic Materials
Authors: Soboyejo ABO , Foster MA , Mercer C , Papritan JC , Soboyejo WO
Published: April 2008

A multiparameter model is proposed for the characterization of fatigue crack growth in structural metallic materials. The model assesses the combined effects of identifiable multiple variables that can contribute to fatigue crack growth. Mathematical expressions are presented for the determination of fatigue crack growth rates, da/dN, as functions of multiple variables, such as: stress intensity factor range, ΔK; stress ratio, R; closure stress intensity factor, Kcl; and the maximum stress intensity factor, Kmax. A generalized empirical methodology is proposed for the estimation of fatigue crack growth rates as functions of these variables. The validity of the new methodology is then verified by making appropriate comparisons between predicted and measured fatigue crack growth data obtained from experiments on selected structural metallic materials. The multiparameter predictions are shown to be in close agreement with experimental data.
Use of the Instrumented Bolt and Constant Displacement Bold-Loaded Specimen to Measure In-Situ Hydrogen Crack Growth in High-Strength Steels
Authors: Vigilante GN , Underwood JH , Crayon D
Published: April 2008

The aggressive environments experienced by large-caliber gun tubes during processing and firing have led to much investigation of the hydrogen-induced cracking susceptibility of high-strength steels. Constant displacement bolt-loaded specimens were used to determine the hydrogen crack growth rates and threshold stress intensities of AF1410, both conventionally and isothermally heat treated, and AerMet 100. The severe susceptibility of high-strength steels necessitated the application and modification of a low-cost, highly reliable in-situ crack measurement method, the instrumented bolt. The instrumented bolt consisted of a full bridge, strain-gaged stainless steel bolt coupled to an automatic data acquisition system. New expressions were developed for use with the instrumented bolt and bolt-loaded specimen to relate load to crack growth. Stage II crack growth rates for the AF1410 were 1.1 × 10-2 and 2.3 × 10-2 mm/s for conventional and isothermal AF1410, respectively. Threshold stress intensity levels for AF1410 were 16.0 and 13.7 MPa ∙ m1/2, respectively. Stage II crack growth rates for AerMet 100 were 2.4 × 10-2 mm/s, while the threshold stress intensity was 14.1 MPa ∙ m1/2.
Mechanisms and Modeling of Near-Threshold Fatigue Crack Propagation
Authors: Petit J , Henaff G , Sarrazin-Baudoux C
Published: April 2008

First, this paper proposes a comprehensive framework for the modeling of the intrinsic FCP (i.e. after elimination of any environmental and closure effects). On the basis of numerous experimental data on Al alloys, steels and Ti alloys, three intrinsic crack growth regimes have been identified: i) stage I regime, observed in single crystals or in the early growth phase of short cracks; ii) stage II regime, commonly observed when the crack advance proceeds along a plane normal to the load axis and results from the activation of symmetrical slip systems; iii) crystallographic stage I-like regime which prevails near the threshold.

Second, this contribution is dedicated to the description of environmentally assisted propagation and specially focused on the understanding of the role of water vapor and the complex interactions existing between environment and microstructure. The effective FCP behavior is described by superimposing two distinct stage II regimes: i) a propagation assisted by water vapor adsorption which can be operative under very low partial pressure or at very low frequencies; ii) hydrogen-assisted propagation which is operative when some critical conditions are encountered.

Constitutive laws are proposed for both intrinsic propagation and water-vapor assisted propagation.
On the Significance of Crack Tip Shielding in Fatigue Threshold — Theoretical Relations and Experimental Implications
Authors: Schindler H-J
Published: April 2008

The fatigue crack growth (FCG) threshold behavior of elastic-plastic materials is analyzed theoretically by simplistic mechanical considerations. Emphasis was laid upon two of the key aspects of threshold, which are both still controversially discussed in the literature: intrinsic threshold and extrinsic crack tip shielding. The analytical relations derived from the model confirm experimental indications, that at R-ratios beyond a certain limit FCG and its threshold is governed by intrinsic mechanisms, whereas at lower R it is crucially influenced by extrinsic shielding mechanisms. The latter are postulated to consist of a crack-closure and a non-closure part, which is confirmed by preliminary experimental data as well as data from the literature. To measure crack closure independently, a new experimental technique, the so-called cut compliance method, is proposed, which is shown by some preliminary tests to work well even in the threshold regime. The model and the derived mathematical relations also enable one to distinguish between those parts of the threshold that are inherently associated with FCG, and the ones that are geometry- or load-history-dependent. Therewith conservatively transferable threshold data can be obtained.
An Indirect Technique for Determining Closure-Free Fatigue Crack Growth Behavior
Authors: Smith SW , Piascik RS
Published: April 2008

The effects of stress ratio (R) and maximum applied stress-intensity factor (Kmax) on fatigue crack growth rate (da/dN) have been investigated. Fatigue crack growth behavior was analyzed by plotting applied cyclic stress-intensity factor (ΔK) versus applied Kmax for an α+β titanium alloy (Ti 6-2-2-2-2) at several values of da/dN. This analysis revealed two distinct regions of fatigue crack growth behavior. At threshold da/dN (≈ 10-10 m/cycle) and for Kmax < 4.6 MPa√m the threshold cyclic stress-intensity factor (ΔKth) is greatly influenced by crack closure. For closure free fatigue crack growth (Kmax > 4.6 MPa√m), a subtle but distinct decrease in ΔKth is observed with increasing Kmax. Plots of ΔK versus Kmax were also generated for AA 2024 test data produced in two different studies. These data also revealed two distinct regions of fatigue crack growth behavior consistent with the Ti 6-2-2-2-2 results. This methodology can be used to determine closure free fatigue crack growth and to monitor subtle changes in ΔKth.
Analyses of Fatigue Crack Growth and Closure Near Threshold Conditions for Large-Crack Behavior
Authors: Newman JC
Published: April 2008

A plasticity-induced crack-closure model was used to study fatigue crack growth and closure in a thin-sheet 2024-T3 aluminum alloy under threshold and constant-Kmax testing procedures. Two methods of calculating crack-opening stresses were compared: one based on contact-K analyses and the other on contact crack-opening-displacement (COD) analyses. These methods gave nearly identical results under constant-amplitude loading but under load-reduction (threshold) simulations the contact-K analyses gave lower crack-opening stresses than the contact-COD method. Crack-growth load-reduction simulations showed that remote closure (crack surface contact away from the crack tip) can cause a rapid rise in opening stresses in the near threshold regime for low-constraint (plane-stress) conditions and high applied stress levels for both low and high stress ratios. Under low applied stress levels and high constraint (near plane-strain) conditions, a rise in crack-opening stresses was not observed near the threshold regime. But the residual crack-tip-opening displacements (CTOD) were of the order of measured oxide thicknesses in the 2024 alloy. In contrast, under constant-Kmax testing, the CTOD near threshold were an order-of-magnitude larger than measured oxide thicknesses. Residual-plastic deformations were much larger than the expected oxide thicknesses. Thus, residual-plastic deformations, in addition to oxides and roughness, play an integral part in threshold development.
Corrosion Fatigue Crack Growth Thresholds for Cast Nickel-Aluminum Bronze and Welds
Authors: Czyryca EJ
Published: April 2008

Fatigue crack-growth rate tests of cast NAB and NAB weld metal specimens were conducted to determine the threshold for fatigue crack growth (ΔKth). The tests were conducted in accordance with ASTM E 647, Standard Test Method for Measurement of Fatigue Crack Growth Rates, in artificial seawater at a cyclic frequency of 2 Hz at R-ratios of +0.05, +0.40, and +0.60. The specimens were machined from both poor and good quality, as-cast NAB. Production NAB weldments were used for NAB weld metal specimens.

The fatigue crack growth-rate curves for duplicate tests at each R-ratio of cast NAB in seawater were analyzed in the near-threshold regime to determine ΔKth. With increasing stress intensity ratio (R), ΔKth decreased. Compared to the values for cast NAB, higher ΔKth and higher crack closure levels in NAB weld metal tests were noted, due to the residual stress in the weldment. The same fatigue crack growth-rate curve sets were corrected for crack closure, and the near-threshold stress intensity decreased significantly when the closure loads were deducted. The closure-corrected, near-threshold stress intensity, based on ΔKeff, ranged from 4.4 to 6.1 MPa-√m for cast NAB versus 4.4 to 7.4 MPa-√m for NAB weld metal.
Fatigue Crack Growth Thresholds Measurements in Structural Materials
Authors: Lindström R , Lidar P , Rosborg B
Published: April 2008

Fatigue crack growth thresholds and da/dN-data at low ΔKI-values (<10 MPa√m) have been determined for type 304 stainless steel, nickel-base weld metal Alloy 182, nickel-base metal Alloy 600, and low-alloy steel in air at ambient temperature and in high-temperature water and steam. The stainless alloys have been tested in water with 0.2 ppm O2 at 288°C and the low-alloy steel in steam at 286°C. The fatigue crack growth threshold was defined as the ΔKI-value resulting in a crack growth rate of 10-7 mm per cycle. The measured fatigue crack growth thresholds (at frequencies from 0.5 to 20 Hz) are quite similar independent of the material and the environment.

A relatively inexpensive and time-saving method for measuring fatigue crack growth thresholds, and fatigue crack growth rates at low ΔKI-values, has been used in the tests. The method is a ΔKI-decreasing test with constant KIMax.
Structures and Activities of ASTM Committee D-27
Authors: Kelly JJ , Getz DM
Published: April 2008

ASTM Committee D-27 on Electrical Insulating Fluids and Gases was formed as Subcommittee IV under Committee D-9 in the year 1916 and was designated as a separate technical committee in 1959. The scope of D-27 is the promotion of knowledge pertaining to insulating liquids and gases, whether synthetic or natural in origin, and the recommendation of standards and specifications pertinent to these materials.

The principal materials included in this arena are oils of petroleum origin, synthetic liquids, and halogenated and other gases when used singularly or as combinations, as electrical insulation or as an environment for electrical insulation in transformers, capacitors, and other electrical equipment.

Standards peculiar to solid insulating materials and varnishes, and the development of standards pertaining to non-electrical uses of liquids and gaseous materials are excluded from our scope.

The D-27 membership is made up of technical people from the refining and chemical industries, electrical equipment manufacturers, electrical utilities, and laboratories that test and analzye both new and used fluids and gases.

The paper presents in some detail the responsibilities of the various subcommittees and the harmonization efforts to work with international standards organizations.

Some specific examples of our work are cited in terms of the events that preceded the need to standardize a procedure.
Sources of Systematic Bias Reflected in an ASTM Collaborative Study on Water in Oil Measured by the Karl Fischer Method
Authors: Margolis SA
Published: April 2008

A collaborative study on the precision and bias of the measurement of water in transformer oils indicated that an acceptable level of precision was achieved using the revised ASTM Test Method for Water in Insulating Liquids by Coulometric Karl Fischer Titration (D 1533-96) and a sample size of 7 mL. Analysis of the distribution of the laboratory results indicates the existence of a systematic bias in the accuracy of the measurement which is related to the instrument design, solvent composition, and calibration of the instrument. Additionally, evidence is presented that indicates that a portion of the water in the oils is not titrated by the coulometric method.
The Electrochemical Stability of Mineral Insulating Oils
Authors: Sabau J , Stokhuyzen R
Published: April 2008

Successful detection of an incipient electrical failure within the windings of power transformers is based upon the possibility of determining the amount and nature of the gases evolved by the oil when subjected to the impact of a strong electric or thermal stress. The cause of the deficiency can be established by analyzing the gases dissolved in the oil. While under normal operating conditions the amount of gas evolved is minimal and therefore of little importance, a significant increase in the concentration of gaseous decomposition products gives cause for concern.

Since a large amount of vulnerable hydrocarbon molecules can also be the source of dissolved gases, the gassing tendency of oil should be taken into consideration. The lack of a reliable procedure capable of establishing a quantitive relationship between laboratory results and the performance of oil in service can influence the interpretation of dissolved gas analysis (DGA). Just as the chemical stability of oil is accepted as an indication of the ability of insulating oils to resist oxidation, the concept of electrochemical stability is introduced as a measure of the capacity of the oil to counteract gas evolution under the impact of electrical stress. Knowledge of the amount of gas generated by a sample of oil, when subjected to the influence of a standard high-voltage field, can improve the interpretation of DGA of that oil. This concept also provides a better understanding of the mechanism by which the high-voltage field negatively affects the chemistry of insulating fluids.
Effect of Gage Length and Test Speed on the Measured Tensile Properties of Geosynthetic Reinforcements
Authors: Kelkar AD , Stevenson PE , Skochdopole TR , Yarmolenko SN
Published: April 2008

This research will specifically address the tensile testing of textile products employing high tenacity industrial quality multifilament twill textile yarns. The research reported in this paper is directed toward developing a repeatable and reproducible test method for textile reinforcements. The paper will present a new testing technique, which uses pressure clamping system as opposed to conventional roller grip systems. The pressure clamping system incorporates a technique used in other disciplines for very strong materials. This technique is the application of sacrificial tabs to the clamping area of the specimen, thus permitting very high jaw pressures without specimen damage. The specific concerns about testing of reinforcing products expressed in the literature are: (1) the effect of sample gage (length) on reported values including tensile strength, extension and modulus, (2) the effect of test speed, i.e. strain rate on reported values: one specific issue is the difference between ASTM at 10% and ISO at 20% per minute, (3) the effect of jaw or grip types on reported values, (4) the control of sample slippage in grips, (5) the amount of tolerable slippage in clamping devices, (6) the accuracy of various extension measurement systems, (7) the effect of the extension measurement system on the reported values, (8) the effect of sample width on reported values, (9) the definition, measurement and reporting of modulus, (10) which modulus is important and (11) what portion of the sample does a reported modulus represent. The paper will focus on four of the concerns. The issues addressed are sample length and sample gage (area of extension measurement), method of extension measurement, test speed and modulus measurements.
Comparative Study of Roller and Wedge Grips for Tensile Testing of High Strength Fabrics with Laser Extensometry: Comparisons to LVDT and Crosshead Extension
Authors: Skochdopole TR , Cassady L , Pihs D , Stevenson PE
Published: April 2008

Measurement of the tensile properties of high strength woven and knit geotextiles and geogrids traditionally make use of roller grip-type clamping systems, which are designed to allow a sample to be pulled in tension without applying an excessive crimping or compressive force on the specimen, thus avoiding premature failure. Roller grips also have the advantage of allowing the specimen to align itself with the applied force and therefore loading the specimen uniformly across the width. However, since the specimen tightens itself around the grip during testing, crosshead travel cannot be used to measure specimen strain, making determination of low strain properties difficult. Two issues that must be addressed in obtaining low strain properties are how to measure sample strain and how to get an accurate and repeatable starting point for the test. This paper will explore alternate methods of gripping systems, strain measurement and data analysis with the objective of accurately measuring and reporting low strain properties of woven and knit geotextiles and geogrids.
Effect of Clamping Mechanism on Pullout and Confined Extension Tests
Authors: Farrag K , Morvant M
Published: April 2008

Two different clamping mechanisms are commonly used in pullout and confined extension tests of geosynthetics. The first method consists of extending the clamps inside the soil to a sufficient length that ensures the confinement of the whole specimen length during testing. The frictional resistance of the part of clamping plates inside the soil is subtracted from the results to obtain the resistance of the geosynthetic specimen. The second method consists of clamping the geosynthetic specimen outside the soil. In this method, displacement measurements are taken in the confined part of the specimen in the soil and, hence, the readings are not influenced by the possible slippage of the specimen between the clamps.

A comparison of test results using both installation techniques is presented and the boundary effects associated with both mechanisms are evaluated. In the tests where the clamps were extended inside the soil, earth pressure near the front facing was measured in order to evaluate the frictional resistance of the clamping plates. Soil pressure measurements were taken after applying the confining pressure and during the test to monitor the development of vertical stresses at the vicinity of the clamping plates. The measurements showed an apparent increase of vertical pressure above the clamps. The results were corrected for the increase of the vertical pressure due to frictional resistance of the clamping plates.

When the clamping plates were connected to the specimens outside the box, displacements were measured along the specimen length. These measurements were extrapolated to determine the front displacement of the specimen at the pullout load application point. The use of the extrapolated front displacement resulted in a more reasonable load-displacement relationship for the geosynthetic specimen.
Wide-Width Strength Test for Nonwoven Geotextiles Without Using Grips
Authors: Elvidge C , Raymond G
Published: April 2008

Development of a simple method of testing nonwoven geotextiles in wide-width testing without using complex grips is presented. The technique has been used mainly on 200-mm-wide samples and has been checked using light 500-mm-wide samples (due to machine testing load limitations on the 500 mm samples). It may be used on any width of geotextile if a testing machine of sufficient capacity is available. The proposed method uses a loop of geotextile that is pulled apart by two bars inserted through the loop. The loop joint is made using heavy duty glue applied by a heat gun. By replacing the glue joint with a seam the method is applicable to testing seams. In order to gauge the accuracy of the method a number of variables were tested. These included two types of polymers, the length of the specimen, the rate of extension, and the direction of extension versus the machine or cross-manufactured direction of the geotextile. The test is quick and the testing technique simple. In the one case where manufacturer's published minimum strength results were available every comparative test obtained exceeded those published results. This shows that the modified methodology has given expected results.
Characterization of Gate Dielectrics with Mercury Gate MOS Current-Voltage Measurements
Authors: Gruber GA , Hillard RJ
Published: April 2008

MOS device performance and reliability depend strongly on the quality of the gate dielectric. Metallic contamination, stoichiometry, interface properties, and substrate quality all have an influence. Gate Oxide Integrity (GOI) measurements are frequently used for monitoring oxide quality and reliability. Conventionally, testing the integrity of these gate dielectrics requires the use of prefabricated polysilicon or metal gate MOS capacitors (MOSCAPs). However, this involves short loop processing that is time-consuming and can itself affect the gate oxide quality. Therefore, a method that can monitor these factors rapidly and accurately for both production and process development is highly desirable. In this paper, a mercury gate is presented for Gate Oxide Integrity (GOI) measurements. This mercury gate is formed using a highly repeatable mercury probe Capacitance-Voltage/Charge-Voltage/Current-Voltage (CV/QV/IV) system. Several applications are discussed that show how these measurements may be used in monitoring a variety of process-induced defects. An example of the application of mercury gate Metal-Oxide-Semiconductor Current-Voltage (MOS IV) measurements for ultra-thin (less than 10 nm) oxide development is also presented.
Assembly Cracks in a Hybrid Nylon and Steel Planter Wheel
Authors: Wilson C , Canfield S
Published: April 2008

In a typical bolted joint, cracks can exist in the fastener, the nut, and either of the two members included in the grip of the fastener. In this paper, the assembly of a hybrid nylon and steel agricultural wheel is studied. Three different cracking problems in the nylon wheel half occurred in the current assembly process. A case study is presented in which the cracking problems arising during the manufacturing and assembly of the hybrid nylon and steel agricultural wheels are addressed. Initially, the cause was thought to be a material processing or fracture mechanics problems. A combination of testing and analysis showed that the root cause was inadequate machine design. After a redesign, cracking problems were eliminated.
The Effect of Fasteners on the Fatigue Life of Fiber-Reinforced Composites
Authors: Brown CR , Wilson DA
Published: April 2008

The effects of stress concentrations on the fatigue life of fiber-reinforced graphite epoxy composites play a very important role in the aerospace industry. Primarily stress concentrations refer to the holes. However, fasteners are the primary manufacturing process for attachment of graphite epoxy panels in use in the aerospace industry today. These conditions of composites with and without fasteners greatly affect the fatigue properties of such panels.

In an attempt to understand the stress field created by fasteners in carbon-reinforced graphite composites, and how these stress fields affect the fatigue life of these composites, a fatigue life analysis program was conducted. It compared specimens with machined fastener holes and specimens with fasteners placed in them. In addition to the fatigue analysis performed on the specimens, photoelastic stress analysis is used to determine the stress field created from the use of fasteners. The difference in stress fields of specimens without fasteners compared to specimens with fasteners can be determined to allow designers to prolong the fatigue life of composites.
Corrosion Control on Concrete Structures: Zinc-Hydrogel Technology
Authors: Piazza JL
Published: April 2008

A discussion of the various deterioration mechanisms on concrete structures including conventional reinforced structures, post-tensioned structures, and prestressed structures in tropical environments will be presented. Corrosion mitigation systems will be reviewed, and new protection methods will be discussed. Key issues in evaluating the performance of different corrosion protection systems on concrete structures will be described. The effectiveness of the different protection methods for corrosion control used historically will be reviewed. Case histories of both failures and successes of the various methods will be discussed. Cathodic protection systems using impressed current and galvanic designs will also be reviewed, and various limitations and advantages of each method will be presented and compared with other corrosion mitigation systems. A new zinc-hydrogel system for cathodic protection of concrete structures which has been used successfully on reinforced, post-tensioned, and prestressed steel structures will be discussed. The design parameters for the different applications of the zinc-hydrogel cathodic protection system will be described, and the effectiveness of this system will be evaluated based on different operating characteristics for each type of structure. The research data used in developing the zinc-hydrogel material will be presented and compared with actual data from commercial installations to verify the long-term operating characteristics. The cost effectiveness of the zinc-hydrogel system will be compared with other cathodic protection systems as well as other corrosion mitigation systems.
French PWR Vessel Surveillance Program Dosimetry: Experience Feedback from More than a Hundred Capsules
Authors: Beretz D , Brillaud C , Destouches C , Saillet S
Published: April 2008

Fifty-eight PWR plants grouped in four standardized series are in operation in the Electricité de France (EDF) reactor pool. About 140 surveillance capsules were extracted and the associated dosimetric analysis carried out according to a defined and approved method described briefly. Taking one of the reactor series as example, the consistency of the results is presented and a comparison is made in terms of fluence with the results of the EFLUVE industrial code set up by EDF. A dosimetry processing improvement study is presented: it aims to take into account the modifications of the fuel management strategy implemented by EDF enabling the lifetime of the power plants to be extended. Finally the analysis of the approach adopted for determination of uncertainties and its improvement is explained.
Reactor Dosimetry in the Surveillance Program of Kozloduy NPP Reactor Pressure Vessels
Authors: Ilieva KD , Belousov SI , Apostolov TG , Monev M
Published: April 2008

The neutron fluence determination methods and approaches applied for Kozloduy NPP reactors of type VVER-1000, Units 5 and 6, and VVER-440, Units 1 to 4, according to the Reactor Pressure Vessel Surveillance Program, are presented. The verification/validation of calculated neutron fluence is carried out by measured activity of ex-vessel detectors installed in the air cavity behind the vessels on units 1 to 6. A methodology for estimation of the neutron fluence for VVER-1000/320 reactor has been developed and applied to surveillance assemblies' sets 1L and 2L of Unit 5 for an assessment of the vessel current embrittlement and prognosis.
Evaluation of the Reactor Dosimetry Results Obtained During the First Ten Years of the RPV Surveillance Program at the NPP Paks
Authors: Zsolnay ÉM , Szondi EJ , Oszvald F
Published: April 2008

Accelerated capsules (LF≈11.7) have been built in the reactors of the Hungarian NPP Paks, for RPV surveillance investigations. As these capsules have been used up in a few years, a new RPV surveillance program has been developed and was put into operation in 1991. The aim of the new program was partly to improve the results of the former one, and hereby to decrease the uncertainty in the RPV service life assessment, partly to introduce “cavity” dosimetry and to monitor the irradiation of the RPV during the remaining service life of the NPP. This paper gives an overview on the reactor dosimetry results obtained with the original RPV capsules — built in by the supplier of the NPP — and, presents the first results of the new program. Conclusions related to the service life of the RPVs are drawn.
Assessment of Activation of Concrete Wall for Decommissioning of Nuclear Power Plants
Authors: Matsumura T , Hattori T , Kawabe T
Published: April 2008

Activation of concrete in wall depends on the incident neutron energy spectrum, composition of the concrete, depth from the wall surface and other parameters. Dependency on the neutron energy spectrum was evaluated by the SCALE system calculations on each important reaction for the activation of concrete. The activation of a concrete wall can be estimated by summing the values of activities for each reaction based on the data of composition of the concrete and the incident neutron energy spectrum.
Neutron Beam Characterization at the Finnish BNCT Facility — Measurements and Calculations
Authors: Serén T , Auterinen I , Kotiluoto P , Seppälä T
Published: April 2008

A Boron Neutron Capture Therapy (BNCT) treatment facility with an epithermal neutron beam has been successfully completed at the Finnish FiR 1 TRIGA reactor at VTT, Espoo. The clinical trials on human patients were started in May 1999. The beam utilizes a specially developed moderator material FLUENTAL™. Extensive measurements and calculations have been carried out to characterize the neutron and gamma fields, both in the “free beam” and in tissue substitute phantoms. Despite the fairly low reactor power (250 kW) an epithermal fluence rate of 1.06 × 109 n cm-2 s-1 is achieved at the beam exit aperture with low fast-neutron contamination. The beam has been modeled in detail using the DORT transport code with the BUGLE-80 library. The neutron spectrum has been adjusted with the LSL-M2 code based on multiple-foil activation. Similar calculations and measurements have been performed by the Finnish BNCT team at the BMRR facility for direct comparison.
Radiation Dosimetry at the BNL High Flux Beam Reactor and Medical Research Reactor
Authors: Holden NE , Hu J-P , Greenberg DD , Reciniello RN , Farrell K , Greenwood LR
Published: April 2008

Radiation dosimetry measurements have been performed over a period of many years at the High Flux Beam Reactor (HFBR) and the Medical Research Reactor (BMRR) at Brookhaven National Laboratory to provide information on the energy distribution of the neutron fluxes, neutron dose rates, gamma-ray fluxes and gamma-ray dose rates. The MCNP Particle Transport Code provided Monte Carlo results to compare with various dosimetry measurements performed at the experimental ports, at the treatment rooms and in the thimbles at both the HFBR and BMRR.
Local Change of a Neutron Spectrum in the Fast Reactor BOR-60 for Extension of Research Tasks
Authors: Tellin AI , Shimansky GA , Yakovleva IV
Published: April 2008

In the fast reactor BOR-60 there have been conducted experimental and calculational investigations of neutron energy spectrum in a cell of the blanket external row assemblies. Two experiments have been carried out. In the first experiment the cell was surrounded by regular blanket assemblies, and in the second one it was surrounded by assemblies containing zirconium hydride (ZrH2). In the chosen cell extended sets of activation detectors were irradiated. Measured reaction rates for various thermal and fast neutron reactions were used to adjust the neutron spectra. For this purpose the STAYNL computer code was used. In each case, calculated neutron spectra were used as a priori. Calculations of neutron spectra were carried out in the two-dimensional hexagonal geometry with the NF-6 code and in the three-dimensional hexagonal geometry with the JARFR code with the ABBN cross section library. The results of the presented comparisons for two configurations are discussed and the results of the investigation of the accumulation of 153Gd from natural europium in the softened neutron spectrum are adduced.
Balakovo-3 Ex-vessel Exercise: Intercomparison of Results
Authors: Borodkin GI , Kovalevich OM , Barz H-U , Böhmer B , Stephan I , Ait Abderrahim H , Voorbraak WP , Hogel J , Polke E , Schweighofer W , Seren TO , Borodin AV , Vikhrov VI , Lichadeev VV , Markina NV , Grigoriev EI , Troshin VS , Penev I , Kinova L
Published: April 2008

The results of an intercomparison of neutron dosimetry measurements in the exvessel cavity of VVER-1000 type reactor are submitted. Good agreement of measured results of different independent participants was found for the different activation reactions. Evaluated absolute dosimetry data are presented. Also good agreement of neutron transport calculation results obtained by as Sn and Monte Carlo methods by independent laboratories with measurements is demonstrated.
Neutron and Non-Neutron Nuclear Data for Radiation Dosimetry
Authors: Holden NE
Published: April 2008

Neutron nuclear data that is used in reactor dosimetry include thermal neutron cross sections and neutron resonance integrals for reactions on a target nucleus. Non-neutron nuclear data used in reactor dosimetry include isotopic compositions of target nuclides and radioactive half-lives, gamma-ray energies and intensities of reaction product nuclides. All of these data are periodically evaluated and recommended values are provided in the Handbook of Chemistry and Physics. The latest recommended values are discussed and they are contrasted with some earlier nuclear data, which were provided with neutron detector foils.
Measurement of the Neutron Capture Cross-Sections for Dy and Hf between 0.001 eV and 50 keV Using Total Energy Absorption Detector
Authors: Cho HJ , Kobayashi K , Yamamoto S , Fujita Y , Kim GN , Chang JH , Ko SK
Published: April 2008

The capture cross sections of Dy and Hf were measured in the energy region from 0.001 eV to 50 keV by using the neutron time-of-flight method with a 46 MeV electron linear accelerator of the Research Reactor Institute, Kyoto University. An assembly of Bi4Ge3O12(BGO) scintillators, which was placed at a distance of 12.7 ± 0.02 m from the neutron source, was employed as a total absorption detector for the prompt capture gamma-ray measurement on the sample. For the capture cross section of Dy, the existing experimental data and the evaluated data in ENDF/B-VI and JEF-2.2 are close to the present result. For the Hf capture cross section, the previous experimental data and the evaluated data in JENDL-3.2 and ENDF/B-VI are in general agreement with the present measurement.
Algorithm and Computer Code of Group Neutron Spectra Transformation
Authors: Shimansky GA , Tellin AI , Gurevich MI
Published: April 2008

The transformation of the group neutron spectrum to the differential form or to group spectra with the other scale of energy groups is necessary in many tasks of reactor dosimetry. If the initial spectrum is given in a fine scale of energy groups, e.g., in the scale SAND-2, so for its conversion in a more rough scale and for an evaluation of a differential spectrum, as a rule, there a method of linear interpolation is used. In this case the linear interpolation method ensures an acceptable precision of the transformation results. If the number of groups of initial spectrum energy scale is not large (less than 100), the application of the linear interpolation method can cause a significant error.

In this work a general-purpose algorithm of spectrum transformation developed by the authors is described. Cubic spline is calculated for the initial spectrum in coordinates (Eφ(E),ln(E)), where E—neutron energy, φ(E)—differential function of flux density. As the spline of the spectral function Eφ(E) contains complete information about the differential neutron flux density, it allows to calculate group flux as well as differential values for an arbitrary energy scale.

The algorithm of the corresponding transformation of the spectrum covariance matrix is described. Both algorithms are realized as a computer code for IBM PC.
A Parametrized Approach for Unfolding the Neutron Flux Spectrum
Authors: Wang Y-Q , Kobayashi K , Li Z-H , Kimura I
Published: April 2008

A parametrized approach, called the modified flexible tolerance, is used to unfold the reactor neutron flux spectrum based on the reaction rates measured by detectors. For the thermal neutron reactor, six parameters are involved. For the neutron flux spectrum of intermediate and fast reactors, the parameters may be reduced to four. for such method, no initial spectrum is required. Our calculations show that the neutron flux spectra obtained for China's SPR and HWRR and Japan's KUR with measured values of reaction rate fit well with those obtained with NEUSPAC code (SAND-II type). The result is also good for the ORR, the MOL-ΣΣ Facility, the YAYOI and the CFRMF. It can be concluded that this method provides an easy and convenient tool for quantitatively understanding the macroscopic characteristics of the neutron flux spectrum.
MCBEND — A Fluence Modeling Tool
Authors: Wright GA , Shuttleworth E , Cowan P , Curl IJ , Mattsson CG
Published: April 2008

Accurate assessment of neutron fluence at reactor pressure vessels and other internal components such as core shrouds is a crucial component of radiation damage studies, which are of fundamental importance in determining plant life. In recent years the Monte Carlo calculation method has become recognized as an accurate tool for such assessments. AEA Technology, through its development of the MCBEND Monte Carlo code in collaboration with BNFL, has been a key innovator in the development of the Monte Carlo method and in making these developments easily accessible to the user. Recent developments aimed at fluence modeling include a source processor, a point energy adjoint capability and geometric sensitivities. The code has been applied to fluence modeling in Magnox gas cooled reactors and PWRs for a number of years : with the work described in this paper it has now also been successfully applied to BWR fluence analysis.
JENDL PKA/KERMA File for IFMIF Project
Authors: Fukahori T , Chiba S , Shibata K , Ikeda Y , Aruga T , Watanabe Y , Murata T , Yamano N , Kawai M
Published: April 2008

The JENDL PKA/KERMA File is prepared from the evaluated nuclear data file, for radiation damage calculations used to support programs such as the International Fusion Material Irradiation Facility (IFMIF). The file contains primary knock-on atom (PKA) spectra, KERMA factors and displacement-per-atom (DPA) cross sections for 78 isotopes of 29 elements in the energy range between 10-5 eV and 50 MeV. The processing code system, ESPERANT, was developed to calculate quantities of PKA, KERMA and DPA from evaluated nuclear data for medium and heavy elements by using an effective single-particle emission approximation (ESPEA). For light elements such as Li, Be, B, C, N and O, the PKA spectra are evaluated by the SCINFUL/DDX and EXIFON codes, simultaneously with other neutron cross sections.
Radiation Hardening in BWR Core Shrouds: Relative Roles of Neutron and Gamma Irradiation
Authors: Kwon J , Motta AT
Published: April 2008

We present a calculation of the displacement rates and freely migrating defect production caused by neutron and gamma irradiation and their roles on causing irradiation hardening in a BWR core shroud. We find that the neutron displacement rate is much higher than the gamma displacement rate, but that the freely-migrating defects produced by gamma irradiation are significant compared to those produced by neutrons. We evaluate the influence of gamma and neutron irradiation on hardening using a point defect clustering model. We find that the influence of gamma irradiation on radiation hardening in the core shroud is small compared to that for neutron irradiation.