bluuebunny/crossref_metadata_2025 huggingface dataset:
Zirconium Alloy E635 as a Material for Fuel Rod Cladding and Other Components of VVER and RBMK Cores
Authors: Nikulina AV , Markelov VA , Peregud MM , Bibilashvili YK , Kotrekhov VA , Lositsky AF , Kuzmenko NV , Shevnin YP , Shamardin VK , Kobylyansky GP , Novoselov AE
Published: March 2009

Data are given on Zr alloy E635 (Zr-l.2Sn-lNb-0.4Fe), developed in Russia as a fuel rod cladding and other component material for use in cores of VVER and RBMK types. The alloy is much superior to binary alloys with 1.0 and 2.5% Nb and Zircaloys in terms of its resistance to irradiation-induced creep and growth and nodular corrosion. The creep rate of the alloy is slightly dependent on irradiation temperature, stress, neutron fluence, and neutron density. The alloy is subject to substantial irradiation hardening while retaining its high-percent elongation. Corrosion, creep, and growth resistances are slightly dependent on the structure of components (alloy, final product). Based on the previously studied influence of impurities, structure, heat treatment, and working schedules, the technological processes were designed and mastered commercially for fabrication of tubes, bars, strips, and fuel rod claddings from this alloy. Components are produced commercially. Fuel assemblies with fuel rods clad in the E635 alloy were successfully tested in the RBMK reactor at the Leningrad NPP as well as in experimental reactors under VVER-1000 conditions. Today, the E635 alloy is recommended as a promising material for use in cores of VVER-1000 and VVER of new generations as well as RBMK-type reactors having a longer fuel cycle.
Tϵ* Integral Under Plane Stress Crack Growth
Authors: Omori Y , Okada H , Ma L , Atluri SN , Kobayashi AS
Published: March 2009

The Tϵ* integral values associated with stable crack growth in A606 HSLA steel SEN specimens were determined experimentally and numerically. The displacement fields obtained through Moiré interferometry and elastic-plastic finite element analysis were used to evaluate Tϵ* associated with the moving crack tip. Tϵ* decreased with the reduction in the size of the integration contour, Tϵ, and continually increased with stable crack growth in this specimen. The measured and computed crack-tip opening angle (CTOA), on the other hand, was a constant 15° during stable crack growth after dropping from the measured and computed initial high values of 35 and 57°, respectively.
Prediction of Stable Tearing and Fracture of a 2000-Series Aluminum Alloy Plate Using a CTOA Criterion
Authors: Dawicke DS , Piascik RS , Newman JC
Published: March 2009

Accurate predictions of stable tearing in a 7.6-mm-thick 2000-series aluminum alloy were made using the critical crack-tip opening angle (CTOA) criterion. The predictions were verified through a comparison of experimental and analytical results. A two-dimensional, elastic-plastic finite element analysis was used to simulate the fracture behavior of a 102-mm-wide C(T) specimen. The analysis determined that a critical crack-tip opening angle (Ψc = 5°) resulted in good correlation with the experimental load against crack opening displacement data. This angle was compared to surface and microtopography CTOA measurements. The angle obtained from the finite element simulation was used to predict the fracture behavior of tests conducted on 102-mm-wide M(T), 305-mm-wide M(T), and 152-mm-wide C(T) specimens. The two-dimensional, elastic-plastic finite element analysis predicted the maximum loads of the 102-mm-wide M(T), 305-mm-wide M(T), and 152-mm-wide C(T) within 3, 4, and 8% of the experimental results, respectively.
The Three Thresholds for Fatigue Crack Propagation
Authors: Miller KJ
Published: March 2009

The three governing threshold conditions in metal fatigue are considered, one relating to crack growth in single crystals, one concerned with crack growth in polycrystalline materials, and one based on linear elastic fracture mechanics (LEFM).

All three conditions are examined in relation to the two physical processes of cracking, i.e., Stage I (shear) and Stage II (tensile) crack growth.

The LEFM threshold is seen as a lower bound condition for fatigue crack growth rate, and the single crystal threshold is viewed in relation to the fundamental threshold pertaining to the fatigue resistance of polycrystalline metals.
Short Crack Growth Behavior
Authors: Sadananda K , Vasudevan AK
Published: March 2009

We have re-evaluated short crack growth behavior using concepts developed recently, and we show that these concepts provide a unified framework that can explain both short and long crack growth behavior without resorting to the crack closure effect. We consider that the behavior of long cracks, including the effects of load ratio, R, is fundamental. We had shown previously that, since fatigue is at least a two-parameter problem in that at least two load parameters are required for an unambiguous description, there are two critical driving forces required simultaneously for fatigue cracks to grow. In extending this analysis to the growth of short cracks, we reject the current notion of the lack of similitude for short cracks and express the similitude as a fundamental postulate that, for a given crack growth mechanism, equal crack tip driving forces result in equal crack growth rates.

We find that, in most short crack problems considered in the literature, the cracks grow in pre-existing stress fields, which are either externally introduced or in situ generated. We refer to them as internal stresses. These can be residual stresses, residual stresses from prior treatment, or stresses generated during cycling. We show here that the observed lack of similitude and the large spread in the data for short cracks are due to: (1) an incomplete description of fatigue crack growth, (2) the variability of the internal stresses, and (3) uncertainties in their quantitative description (elastic versus elastic-plastic). We consider that the short cracks also grow at the same two thresholds as the long cracks, when all the components that contribute to the crack tip driving forces are included. In fact, short crack growth behavior confirms our concept that two parameters are required to define fatigue; consequently, for fatigue cracks to grow, two thresholds need to be satisfied simultaneously. We present examples from the literature to illustrate the concepts discussed.
Resistance Spot Weld Failure Loads and Modes in Overload Conditions
Authors: Zuniga S , Sheppard SD
Published: March 2009

The failure modes of two single-weld specimens, the coach-peel and the tensile-shear specimens, were studied in detail. Weld overload experiments, along with optical and scanning electron microscopy, revealed that the coach-peel specimen failed by microvoid coalescence (ductile fracture) near the weld nugget/heat affected zone (HAZ) boundary and that the tensile-shear specimen failed predominately by localized necking (shear localization) near the HAZ/base metal boundary. Empirical data extracted from measurements performed on metallurgical cross sections of interrupted coach-peel and tensile-shear specimens established the deformed characteristic material distance (coach-peel) and the existence of a critical thickness strain for localized necking (tensile-shear). These quantities were used to predict weld failure via finite element analysis as described in Ref 1.

The work presented here is the first step in a larger project that is focused on developing a methodology for predicting spot weld overload failure in detailed finite element simulations of spot-welded joints. This methodology is based upon the failure phenomena (as reported here) and detailed characterization of the HAZ (as reported in Ref 1). The main requirement of this predictive methodology is that it be adaptable to any combination of joint configuration and loading direction. This predictive methodology will serve as the basis for the final step of developing a model of resistance spot weld failure based upon a simpler representation of the spot weld that can be used in car crash simulation models.
On Thermal Fatigue of Nickel-Based Superalloys
Authors: Meyer-Olbersleben F , Engler-Pinto CC , RézaÏ-Aria F
Published: March 2009

The thermal fatigue (TF) behaviour of two single crystal nickel-based super-alloys, SRR99 and CMSX-4, is reported. Single edge wedge specimens are rapidly heated by induction heating of the wedge tip to a maximum temperature between 1000‡C and 1175‡C and cooled to 200‡C by forced air. A constant cycle period is employed for all experiments. The strain distribution along the edge of the TF specimens is measured. Changing the induction frequency leads to different strain ranges. CMSX-4 shows crack initiation always on cast microporosities. SRR99 presents an additional oxidation/spalling/re-oxidation mechanism under low strain loading. An “integrated approach” combining TF and TMF (thermo-mechanical fatigue) is proposed. The applied TMF temperature-strain cycle is deduced from the measured TF-cycle. Under this new temperature-strain cycle the crack initiation life and the total life in TMF for SRR99 are compared with the TF results.
Crack Initiation in an Aluminide Coated Single Crystal During Thermomechanical Fatigue
Authors: Martínez-Esnaola JM , Arana M , Bressers J , Timm J , Martín-Meizoso A , Bennett A , Affeldt EE
Published: March 2009

Two different modes of coating crack initiation are observed in an aluminide coated single crystal nickel base alloy upon thermomechanical fatigue loading with a cycle where the lag of the strain cycle behind the temperature cycle was 135‡. Minimum and maximum cycle temperatures were 300‡C and 1050‡C, respectively. At applied mechanical strain ranges in excess of 0.8% the coating fails in a brittle manner, initiating a network of nearly equidistant parallel cracks. As opposed to this line initiation mode, a point initiation mode of multiple thumbnail crack origins is found for low strain ranges. Uncoated test specimens fail by point initiation at all strain ranges. The line initiation behaviour can be rationalized using a fracture mechanics approach based on energy release rate concepts to estimate the strain (or stress) to first coating crack and to predict the coating crack density during the test. This model highlights the effects of various parameters, such as coating thickness and temperature, on the failure mode. The influence of the ductile-brittle transition temperature and the stress-temperature coupling on the failure mode of the coating is discussed and the model predictions are compared with the experimental observations.
Damage Structures of Proton Irradiated Fe-0.3wt.%Cu Alloy
Authors: Kimura A , Shibamoto H , Yuya H , Hasegawa M , Yamaguchi S , Matsui H
Published: March 2009

Microstructural observation was performed on an Fe-0.3wt.%Cu alloy using a cross-sectional method. The specimens were solution treated and aged at 893K for 22.5h, followed by proton irradiation up to a fluence of 3×1021H+/m2(0.2 dpa at a peak position) at 353K. A band of structure, 0.8μm wide, was observed in a region 6.5 μm beneath the irradiated surface. The band consisted of a high density of black spot damage, which average size and number density at the center of the band was determined to be 2.3nm and 2.2×1026/m3, respectively. Besides the black spot damage, a number of small structures (<3nm) were observed in the defect band at strong two beam condition, while precipitates having F.C.C structure with a lattice constant of 10.16A and large precipitates (>6nm) causing halo rings corresponding to F.C.C. copper were observed at the region in and around both sides of the band. Taking in account results of micro vickers hardness and positron life-time measurements in Fe-Cu alloys, radiation hardening observed in Fe-0.3wt.%Cu alloy is attributed mainly to the radiation damage structures, such as dislocation loops and microvoids. However, It is pointed out that interaction between copper and carbon plays an important role on the microstructural evolution under irradiation and the resultant hardening in Fe-C-Cu alloys.
The Interpretation of Charpy Impact Test Data Using Hyper-Logistic Fitting Functions
Authors: Helm JL
Published: March 2009

The hyperbolic tangent function is used almost exclusively for computer assisted curve fitting of Charpy impact test data. Unfortunately, there is no physical basis to justify the use of this function and it cannot be generalized to test data that exhibits asymmetry. Using simple physical arguments, a semi-empirical model is derived and identified as a special case of the so called hyper-logistic equation. Although one solution of this equation is the hyperbolic tangent, other more physically interpretable solutions are provided. From the mathematics of the family of functions derived from the hyper-logistic equation, several useful generalizations are made such that asymmetric and wavy Charpy data can be physically interpreted.
Effects of Metallurgical Variables on Swelling of Modified 316 and Higher Ni Austenitic Stainless Steels
Authors: Shibahara I , Akasaka N , Onose S
Published: March 2009

The effects of solute elements and cold-work on swelling in modified 316 and higher Ni advanced austenitic stainless steels developed for FBR core material were investigated together with the posted model alloys. The Si, P, B, Ti, Nb modified and cold-worked steels exhibited an improved swelling resistance. In the temperature range between 400 and 500°C, the swelling was suppressed significantly by an addition of 0.8 wt% Si. The beneficial effect of Si appears to be reduced in the steels without Ti and Nb tending to form γ′ precipitates. In the temperature range between 500 and 600°C, a needle-like phosphide precipitates played an important role in suppressing void growth. Additions of Ti and/or Nb were found to stabilize the phosphide phase and extended the swelling incubation period. In the improved austenitic steels, the synergistic effect of cold-working and P,B,Ti,Nb additions act beneficially to stabilize the dislocation structure and to form finely dispersed precipitates during irradiation.
An Investigation of Microstructures and Yield Strengths in Irradiated Austenitic Stainless Steels Using Small Specimen Techniques
Authors: Toloczko MB , Lucas GE , Odette GR , Stoller RE , Hamilton ML
Published: March 2009

Transmission electron microscopy (TEM) specimens of a first core heat of 316 stainless steel, in both the solution annealed and 20% cold worked condition, were irradiated to 46 dpa at 420°C, to 49 dpa at 520°C, and to 34 dpa at 600°C in FFTF/MOTA. Prior to irradiation, some of the specimens were pre-implanted with approximately 100 appm of helium over one-third of the specimen thickness. Microstructures and mechanical properties of these specimens were examined. Microstructural data was taken from unimplanted zones and were consistent with data in the literature for unimplanted 316 SS. Where possible, irradiation hardening of the alloys was experimentally evaluated by microhardness and shear punch. For comparison, irradiation hardening was also calculated using a barrier hardening model and the microstructural data. Experimentally measured values of yield stress were in agreement with the range of values reported in the literature regardless of helium pre-implantation and were similar to the calculated values.
Saturation of Swelling in Neutron Irradiated Pure Nickel and Its Dependence on Temperature and Starting Dislocation Microstructure
Authors: Stubbins JF , Garner FA
Published: March 2009

Pure nickel was irradiated in EBR-II without active temperature control to two exposures levels (14 and 31 dpa) at target temperatures of 425, 500, and 600°C in three starting conditions: annealed, 30% cold worked, 30% cold worked and aged at 650°C for 10 hr. The same material conditions were irradiated with active temperature control in FFTF to 33–36 dpa at 430, 520, and 600°C. Post-irradiation density measurements show that in the annealed condition swelling tends to saturate at levels strongly dependent on irradiation temperature. In EBR-II at 600°C. saturation occurs before 12 dpa but swelling is still increasing slowly at 425 and 500°C. The tendency toward saturation of swelling is enhanced by cold working. In addition, the temperature dependence of the saturation level is strongly decreased by cold-working. The maximum swelling under most irradiation conditions is on the order of 8%. In the isothermal FFTF irradiations, the effectiveness of cold working in promotion of swelling is much less pronounced at the higher irradiation temperatures, particular at 600°C. These results are consistent with most evidence from other neutron and charged particle irradiation studies on pure nickel. In comparing the results of these and previous studies, it appears that the saturation is linked to a progressive collapse of the dislocation network when voids begin to dominate the microstructure.
Variable Energy Positron Measurements at Nitrogen Ion Bombarded Steel Surfaces
Authors: Brauer G , Kolitsch A , Schut H , van Veen A
Published: March 2009

Nitrogen ion bombardment of steel samples has been studied by utilizing the Delft variable energy positron beam facility. The energy of the beam was varied between 250 eV and 25 keV and a line-shape parameter S describing the annihilation radiation has been measured. By use of the VEPFIT fitting programme, up to five different layers, each having different densities, could be identified and characterized. The results show that carbon layers deposited during nitrogen implantation can be observed. A relation between the measured depth profiles of nitrogen, carbon and oxygen by Elastic Recoil Detection Analysis (ERDA) and the results of positron annihilation is given and discussed. The wear and friction properties of the steel surfaces before and after nitrogen implantation are presented.
Comparison of Static and Impact Energy Absorption of Carbon Fiber/PEEK Composite Tubes
Authors: Hamada H , Ramakrishna S
Published: March 2009

Carbon polyetheretherketone (PEEK) composite tubes with different fiber orientations of 0°, ±5°, and ±10° have been investigated. Composite tubes were tested under two different conditions. One set of tubes was quasi-static tested at 1.67×10−5 m/s using a servo-hydraulic machine. Another set of tubes was impact tested at 8.5 m/s using a drop-weight testing machine. All the composite tubes were progressively crushed from the chamfered end. Quasi-static-tested tubes displayed higher specific energy absorption than the impact-tested tubes. This difference was attributed to the changes in the crushing mechanisms with the crushing speed. Quasi-static-tested tubes were crushed by splaying of tube wall into well-defined fronds whereas impact-tested tubes were crushed by brittle fracture of the tube wall. Brittle fracture of the tube wall was attributed to the reduced fracture toughness of carbon/PEEK composite materials at high strain rates. The specific energy absorption capability increased with increasing θ. The large number of fiber fractures observed in the crush zone might have contributed to the superior energy absorption capability of ±10° tubes.
Micromechanical Characterization of Nonlinear Behavior of Advanced Polymer Matrix Composites
Authors: Gates TS , Chen J-L , Sun CT
Published: March 2009

Due to the presence of curing stresses and oriented crystalline structures in the matrix of polymer matrix fiber composites, the in situ nonlinear properties of the matrix are expected to be rather different from those of the bulk resin. A plane-stress micromechanical model was developed to retrieve the in situ elastic-plastic properties of Narmco 5260 and Amoco 8320 matrices from measured elastic-plastic properties of IM7/5260 and IM7/8320 advanced composites. In the micromechanical model, the fiber was assumed to be orthotropically elastic and the matrix to be orthotropic in elastic and plastic properties. The results indicate that both in situ elastic and plastic properties of the matrices are orthotropic.
Effect of Stacking Sequence on Delamination Toughness and Delamination Growth Behavior in Composite End-Notched Flexure Specimens
Authors: Davidson BD , Altonen CS , Polaha JJ
Published: March 2009

Results are presented from an experimental investigation of the effects of stacking sequence on the delamination toughness and delamination growth behavior exhibited by laminated composite end-notched flexure (ENF) test specimens. Delamination growth is studied at interfaces defined by 0°/0°, +15/−15°, +15/+15°, +30/−30°, and +30/+30° plies in a typical graphite/epoxy. A previously developed “ENF test design procedure” is used to aid in the determination of specimen stacking sequences and test geometries, such that delamination growth occurs at the interface of interest, yet the contributions to the energy release rate from residual thermal stresses, geometric nonlinearities, local Mode II concentrations at the specimen's free edges, and local Mode III effects are minimized. Critical strain energy release rates are obtained from the load-deflection test data by both a classical plate theory-based data reduction technique and by a compliance calibration procedure and the results compared. It is shown that compliance calibration is the only completely reliable means of reducing the data from either unidirectional or multidirectional ENF tests. It is also shown that the proposed ENF test design procedure reduces or eliminates the propensity for subcritical delamination growth at the free edges of an ENF specimen. For specimens that are not precracked, there is no significant effect of interfacial ply orientation on GIIc for the material and relative angles studied.
Research and Standardization Needs for Direct Push Technology Applied to Environmental Site Characterization
Authors: Farrar JA
Published: March 2009

Research and standardization needs in the area of direct push sampling and testing is reviewed. Direct push testing and sampling is a rapidly growing area in environmental site characterization. Direct push active soil gas sampling techniques are well accepted for environmental site investigations in the vadose zone. Standardization efforts are underway. Better guidance is needed on purging, sealing, and avoidance of cross contamination. The cone penetration test is gaining popularity due to it's excellent stratigraphic mapping capability and water pressure information. Research is needed to refine hydrostatic pressure measurement capability and prediction of hydraulic conductivity. Discrete point water sampling using protected screen samplers has gained wide acceptance. Research is needed concerning water sample protection, effective sealing, use of vacuum in low hydraulic conductivity soils. Comparison studies should be done in the laboratory and in the field. The greatest area of research interest is in development of chemical sensors for use in direct push testing. Several promising methods using fiber optic laser technologies are being developed. Successful technology transfer to everyday application in private industry will require sensors be developed into fully tested, rugged, simple modules to be housed in a penetrometer body. Full scale testing under laboratory controlled conditions will help in validation of advanced sensor systems.
Development of a Process for Toughening Grain-Refined, High-Strength Steels
Authors: Leap MJ , Wingert JC , Mozden CA
Published: March 2009

There is a gradually increasing awareness of the deleterious effects of grain-refining precipitates on the Charpy V-notch impact toughness of high-strength steels, and recognition of these effects resulted in the development of a general process that provides substantial improvements in the ductile fracture resistance of tempered mar-tensite. The results of this investigation indicate that the processing-induced refinement of grain-refining precipitates also provides significant improvements in the lower-shelf and transition toughness of 3310, 8219 and 4340 steels tempered at 180‡C and 4340 steel tempered at 593‡C. In contrast to the upper-shelf regime, where the application of the process produces a change in either the mode or character of unstable fracture at constant strength and austenite grain size, the refinement of grain-refining precipitates is associated with an increased amount of ductile fracture and an increased resistance to the initiation of unstable crack propagation at any given temperature in the lower-shelf regime.
Development of High Strength 12% Cr Ferritic Steel for Turbine Rotor Operating above 600‡C
Authors: Tsuda Y , Yamada M , Ishii R , Tanaka Y , Azuma T , Ikeda Y
Published: March 2009

An advanced 12% chromium ferritic steel has been developed for the high-temperature rotors in improved fossil-fired power plants. The development of this steel is based on the experimental studies of various 12% chromium heat resistant steels. Effects of alloy elements on the creep rupture strength have been investigated and the 10Cr-1.8W-0.7Mo-V-3Co-Nb-B steel was selected to be a hopeful candidate. This revealed the creep rupture strength was higher than that of 10Cr-1Mo-1W-V-Nb rotor steel being used at 593‡C.

The producibility and properties of the new steel have been verified with the medium size trial forging manufactured from a 20 ton ingot. Although a few technical subjects are remaining, these are expected to be solved with the modification of the manufacturing process.

This newly developed high strength 12% chromium ferritic steel is expected to be applicable to high-temperature rotors operating at 630‡C or above, and the significant improvement of thermal efficiencies would be obtained in fossil-fired power plants.
Electrochemical Methods for On-Site Determinations of Corrosion Rates of Rebars
Authors: Feliú S , González JA , Andrade C
Published: March 2009

A review on the available electrochemical methods is presented for the on-site determination of rebar corrosion rate. In real size structures the methods available at present may be classified in three groups: A) Confinement of the applied electrical signal, B) Measurement of the lateral spreading of the electrical signal and C) Minimization of this lateral spreading. From these three alternatives, the first one has been implemented in a device that is now currently used for on-site measurements. This device is based in a “controlled” guard ring. In real size structures, the normal values of corrosion rates recorded are of the same order of magnitude of those previously measured in laboratory experiments. The levels are classified in: negligeable, low, moderate and high.

The gaps in the knowledge which still need to be investigated are also, commented: 1) unconfined measurements, 2) effect of counterelectrode size, 3) the true meaning of the corrosion rate measured, 4) constant B value, 5) current distribution around rebar perimeter 6) relation between mean corrosion rate and maximum pit depth and 7) identification of local corrosion. Finally, the role of embedded sensors on the monitoring of rebar corrosion risk, is mentioned.
Inelastic Deformation Mechanisms in SCS-6/Ti 15-3 Metal Matrix Composite (MMC) Lamina Under Compression
Authors: Newaz GM , Majumdar BS , Brust FW
Published: March 2009

An investigation was undertaken to study the inelastic deformation mechanisms in [0]8 and [90]8 Ti 15-3/SCS-6 lamina subjected to pure compression. Monotonic tests were conducted at room temperature (RT), 538°C, and 650°C. Results indicate that mechanical response and deformation characteristics were different in monotonic tension and compression loading whereas some of those differences could be attributed to residual stress effects. There were other differences because of changes in damage and failure modes. The inelastic deformation in the [0]8 lamina under compression was controlled primarily by matrix plasticity, although some evidence of fiber-matrix debonding was observed. Failure of the specimen in compression was due to fiber buckling in a macroscopic shear zone (the failure plane). The inelastic deformation mechanisms under compression in [90]8 lamina were controlled by radial fiber fracture, matrix plasticity, and fiber-matrix debonding. The radial fiber fracture was a new damage mode observed by MMCs. Constitutive response was predicted for both the [0]8 and [90]8 laminae, using AGLPLY, METCAN, and Battelle's Unit Cell FEA model. Results from the analyses were encouraging.
Digital Elevation Data, Landsat TM and Magnetic Data for Visualization of Geomorphological and Geological Features
Authors: Wester K , Lundén B
Published: March 2009

The main objective of this study is to develop methods for optimizing and merging different types of digital data for visual interpretation of geological lineaments and geomorphology. Two test areas with different topographic variability were selected in the Scandinavian mountain region.

Different methods for enhancement based on convolution, both directional and non-directional, were applied on elevation data to detect subtle structural features. An excellent product for visual interpretation of lineaments is the artificial stereo pairs, using raw elevation data for the topography and spatially enhanced elevation data as background.

The best spatial enhancement of Landsat TM images was achieved by unsharp masking and adaptive contrast stretch. To visualize the topography when analyzing satellite imagery, artificial stereo pairs were created using elevation data with Landsat TM data as background.

Using synthetic stereo pairs solely based on magnetic data it was possible to find subtle magnetic anomalies. Also, together with elevation data, artificial stereo pairs were created with magnetic data as background color. This product allows interpretation of the relationship between topographic lineaments and magnetic anomalies.

The image products presented here will not replace traditional maps and mapping methods; however, used as supplementary tools they may increase the understanding of many various geological and geomorphological phenomena. The techniques can provide some of the useful products needed for a complete environmental site characterizations.
Risk of Traumatic Death During Downhill Skiing Compared with that During Mountaineering
Authors: Burtscher M , Nachbauer W , Schröcksnadel P
Published: March 2009

To determine the risk of traumatic death associated with various mountain sports and to locate risk groups, we registered the fatalities incurred during skiing and mountaineering in Austria within a seven-year period. From a total of 1833 fatalities, 656 Austrians aged 16 or above were included for risk calculations. Traumatic deaths (TDs, 74%) and sudden deaths (SDs, 24%) represented 98% of all fatalities, whereby the traumatic death proportion was highest in climbers (97.5%). We found that the annual traumatic death rate per 100 000 persons increased from downhill skiing (0.52) to ski touring (1.57) to hiking (2.62) and rock and ice climbing (6.60). Traumatic deaths occurred more frequently with increasing age, and men were clearly more endangered than women. In persons engaging more regularly in mountain sports activities, the traumatic death risk was reduced during downhill skiing and hiking but it was relatively enhanced during climbing and ski touring.
Skier Injury Trends—1972 to 1994
Authors: Johnson RJ , Ettlinger CF , Shealy JE
Published: March 2009

Between December 1972 and April 1994 the authors evaluated prospectively 8023 injuries reported to the injury clinic operated in the base lodge of a moderate size northern Vermont ski area. During that time, approximately 2 480 000 skier-visits occurred at the area. This study is the most recent update of reports documenting long-term trends that have been presented at approximately four-year intervals. Although the overall injury rate decreased by 44% during the 22-year study, most of this decline occurred during the first ten years. Fractures and sprains to the lower leg, however, continued the improvement noted in previous reports with an 87% reduction. Although the incidence of knee ligament injuries did not change significantly, severe knee sprains, usually involving the anterior cruciate ligament, increased very significantly (228%), continuing a trend that began in the late 1970s. In general, the incidence of upper body injuries did not change although upper body lacerations and thumb ulnar collateral ligament sprains improved by 65 and 61%, respectively, while clavicular and trunk fractures, though rare, increased in incidence 234 and 202%, respectively.
Gender Differences in Alpine Skiing Injuries: A Profile of the Knee-Injured Skier
Authors: Greenwald RM , Toelcke T
Published: March 2009

We have previously reported on gender differences in injury patterns at a large Utah ski resort. A total of 7307 injuries during 1989 to 1995 (53% men, 47% women) have been treated at the emergency clinic at the resort base. This study was an attempt to determine if there are factors related to skier demographics or conditions surrounding a knee injury that might be relevant to attempts to reduce the high incidence of these injuries. An analysis of our prospective data including 817 knee injuries over the past three ski seasons indicated that there are significant differences in demographics and injury descriptions between men and women who seriously injure their knee. Knee injury type and degree of ligamentous rupture were compared to gender, age, skier ability, direction of fall, and binding release as reported by the skier immediately following the injury. Only those injuries sustained while skiing were included. A total of 536 women and 281 men sustained knee injuries, with 55% and 43%, respectively, of these injuries being a Grade III rupture of the anterior cruciate ligament (ACL). There was a statistically significant difference in the number of knee injuries compared to all injuries between men and women (p < 0.01). Within the knee injury group, neither age nor direction of fall significantly influenced the type or degree of knee injury, while there was a significant difference between men and women related to a binding release surrounding an injury event. Isolated ACL injuries occurred much more often in advanced skiers than in beginners, while ACL rupture coupled with other soft tissue injury, particularly to the medial collateral ligament (MCL) were significantly more common in beginners. Detailed information regarding the circumstances surrounding these injuries can be especially useful in determining how to teach people what positions and fall situations are typically the most dangerous, or in providing equipment manufacturers with information needed to try to modulate loads to certain parts of the body under certain skiing situations. Future research will continue to analyze these disparities between the sexes in percentage of knee injuries to total injuries and in the significant lack of binding releases in women sustaining knee injuries.
Breathability and Protection Aspects of Moisture Barriers Used in Fire Fighters Protective Clothing After Thermal Aging
Authors: Rossi RM , Zimmerli T
Published: March 2009

The effect of heat on the water vapor permeability and the watertightness of different breathable fabrics has been analysed. Samples have been exposed to a radiant heat source or were put in an oven for definite times with assessment of the changes in their waterproof and breathable properties. This study shows that microscopic changes in the structure of several materials occur after very short exposures to heat which cause a reduction in the breathability of most materials. The waterproof properties, however, remain unchanged as long as no visible damage has occurred. The microscopic changes in the structure can lead to a decrease of the breathability of heat exposed samples of more than 30%.
Comparison of Conductive Heat Resistance and Radiant Heat Resistance with Thermal Protective Performance of Fire Fighter Protective Clothing
Authors: Stall JO
Published: March 2009

This study was intended to support the development of new test technology and requirements for possible inclusion in the 1997 edition of NFPA 1971, Standard on Protective Ensemble for Structural Fire Fighting. The particular focus of this study was to examine test methods related to the thermal protection of fire fighter protective clothing. Both conductive heat resistance and radiant heat resistance performance areas were investigated for a number of composites and compared with thermal protective performance test results. Conductive heat resistance testing was conducted using Test Method F 1060 while radiant heat resistance testing was performed using procedures in NFPA 1976, Standard on Protective Clothing for Proximity Fire Fighting. In addition, different key variables were examined for each type of test to show the effects of exposure temperature, moisture, and pressure in the case of conductive heat resistance, and radiative heat flux for radiant heat resistance testing. The study demonstrated that different test methods rank materials systems differently and that no one test can be used to predict performance in all fire ground situations. The effects of specific variables for some tests indicated a range of performance for the different material systems evaluated. For example, conductive heat resistance showed varying effects for moisture in clothing systems—sometimes augmenting performance, in other cases diminishing protection times. The study offers a number of recommendations for further development of test methods and performance criteria which can be applied to fire fighter protective clothing.
Protection and Comfort — A Sweating Torso for the Simultaneous Measurement of Protective and Comfort Properties of PPE
Authors: Zimmerli T , Weder MS
Published: March 2009

The aspects of protection and comfort are both very important for the performance of personal protective equipment. For a realistic testing of protective clothing it is essential to have the possibility to assess the protective and the comfort properties simultaneously, because they are influenced by each other. The design and construction of a sweating torso are described which allows this simultaneous assessment. The thermal properties of the torso are chosen in such a way that the correspondence to a human body is as close as possible. Measurements of the protection against cold and the comfort properties of different sleeping bags are presented. They show that the cold protection, i.e. the thermal insulation, is strongly influenced by the evaporation of sweat. Further measurements are planned with the sweating torso covered with heat protective clothing and exposed to a source of radiant heat.
Fire Fighters' Protective Clothing and Thermal Environments of Structural Fire Fighting
Authors: Lawson JR
Published: March 2009

Fire fighters' protective clothing is designed to perform several functions. Of these, protection from heat and flame is one of the most important. Today's fire fighter protective clothing designs are based on years of field experience and research studies which addressed structural fires. Much of this work has concentrated on the fire environment where a fire fighter suddenly becomes enveloped in flames. This exposure generally results in serious life threatening injuries and sometimes death. Little appears to have been done to address the conditions where most burn injuries occur, outside of the flaming envelope. This paper attempts to define the general thermal environment at locations where fire fighters stage and begin their attack on a fire.

A great deal of research has been done to evaluate structural fires as they relate to building design, materials and contents. Only small elements of these data have been used in evaluating the thermal environment around fire fighters during normal attack situations. Results from early and recent studies clearly demonstrate the severity of thermal environments at fire attack staging areas. The flow of hot gases from a doorway or through a window may be well above 400°C (752°F) and may extend tens of meters down a corridor or across an adjoining room ceiling. Thermal radiation from a room's open doorway or window may reach levels which will cause burn injuries to exposed skin and cause charring or ignition of protective clothing fabrics which result in burn injuries to protected skin. Surface temperatures of solids within this staging zone may easily exceed 100°C (212°F), and touching these surfaces without protection could result in a sudden burn injury. A brief scenario is presented which serves as an example of how a fire fighter could receive second degree burns while attacking a fire from outside of the flaming envelope.
Ski Injuries Among Ski Area Employees
Authors: Belanger M , Ettlinger CF , Shealy JE , Johnson RJ
Published: March 2009

This study was undertaken to compare injuries sustained by recreational skiers with those of a group of ski patrollers and ski instructors. The study includes 3825 injuries occurring at a medium-size ski area in northern New England from 1986–87 to 1990–91 (five seasons). A total of 124 injuries were sustained by expert employee skiers. In comparison with recreational expert skiers, employees were more likely to sustain minor knee sprains and less likely to sustain serious knee sprains or fractures. There was no significant difference in lower leg (potentially equipment related) injuries. Analysis of activity at the time of injury showed that patrollers running sleds and instructors skiing on a racecourse were the riskiest activities for employee skiers. The study provides guidelines and a simple methodology for evaluating injury data among employees at ski areas of all sizes. These guidelines can be used even when injury data on the general population are limited.
The Use of Electrochemical Noise to Investigate the Corrosion Resistance of UNS Alloy N04400 Nuclear Heat Exchanger Tubes
Authors: Brennenstuhl AM , Palumbo G , Gonzalez FS , Quirk GP
Published: March 2009

Underdeposit corrosion of freshwater-cooled shutdown heat exchangers (SHX) and steam generators (SG) resulted in unscheduled unit shutdowns very early in the life of the Ontario Hydro Pickering B Nuclear Generating Station, whereas the same SHX and SG in the identical A station had not experienced any problems in over 19 years of operation. UNS alloy N04400 tubes were used for SHX and SG at both stations. Because detailed metallurgical analysis of tubes removed from the A and B stations suggested that alloy differences may be a major factor to the early failures at the B station, an investigation to characterize the corrosion resistance of the two alloys was carried out. From standard accelerated corrosion test methods it was inferred that the A and B alloys had similar corrosion resistance, suggesting that subtle but important material differences may have been masked by the aggressiveness of the test methods. Therefore, the electrochemical noise measurement (ENM) technique in conjunction with less aggressive test environments was used to characterize better the corrosion resistance of the A and B alloys. Variations in the corrosion resistance of the material removed from Pickering A and B heat exchangers (HX) were evident. During an initial exposure to deionized (DI) water at a pH of 5, the B alloy generally displayed greater passivity than the A material. However, the B alloy exhibited far less corrosion resistance than the A material when the pH of the water was reduced to 1 by the introduction of a nitric acid/acetic acid mixture. The predominant mode of degradation in the B material was intergranular attack with some localized corrosion in grain interiors. The A alloy, on the other hand, exhibited general corrosion.

The study also showed that the corrosion resistance of the A alloy was markedly reduced by heat treatment. A solution heat treatment at 900°C for 1 h followed by a cold-water quench or furnace cool from this temperature led to a corrosion performance similar to the nonheattreated B alloy. The same heat treatment did not significantly alter the corrosion performance of the B alloy. Changes in the mode of attack of the A and the B alloys were also observed when samples had been thermally treated. Both exhibited crystallographic attack, which was very localized in some areas. Transmission electron microscopy and secondary ion mass spectrometry revealed changes in the microstructure, which may account for the differences in the mode of attack. The predominant precipitate chemistry in the A alloy was Cr23C6, whereas in the B material it was titanium carbide. The B alloy also displayed boron segregation at the grain boundaries. This seemed to influence the extent of intergranular attack in this alloy.
The Effect of Some Fundamental Aspects of the Pitting Corrosion of Stainless Steel on Electrochemical Noise Measurements
Authors: Pistorius PC
Published: March 2009

Features of metastable pit growth on stainless steel that affect the possibilities to predict stable pit growth from electrochemical noise measurements are examined. To this end, the behavior of AISI type 304 stainless steel in chloride solutions has been studied. It is confirmed that the electrode capacitance plays a major role in fluctuations of the corrosion potential during metastable growth. This means that the size of these potential fluctuations depends primarily on the size of metastable pits and not on the peak current nor the current density during growth; this means that fluctuations in electrode potential will have little value to predict stable pitting. Electrochemical current noise from twin-electrode noise probes holds more promise. However, it is shown that the direct relationship between electrochemical current noise and pitting susceptibility breaks down when the pitting behavior is altered by a change in surface condition (heat tinting).
Interfacial Measurements and Fracture Characteristics of Single and Multi-Fiber Composites by Remote Laser Raman Microscopy
Authors: Galiotis C , Chohan V , Paipetis A , Vlattas C
Published: March 2009

The micromechanics of stress transfer in single-fiber as well as multi-fiber composites were investigated. The material system under investigation consisted of high modulus carbon fibers embedded in an epoxy resin. The point-by-point stress in the fiber was measured using the newly developed technique of remote laser Raman microscopy (ReRaM). The composite specimens were loaded incrementally in tension and the stress transfer profiles emanating from fiber discontinuities, such as fiber breaks, were closely monitored. At each applied stress level, the interfacial shear stress (ISS) distribution was derived by means of a balance of shear-to-axial forces argument. In the single-carbon fiber/epoxy system, a maximum interfacial shear stress of 30 MPa was reached at the point of first fiber fracture. In the multi-fiber carbon fiber/epoxy system, the maximum interfacial shear stress developed at the point of first fiber fracture was of approximately the same magnitude. Finally, the local stress concentration in the intact fibers, as a result of an adjacent fiber fracture, was determined as a function of distance from the fiber fracture for three distinct levels of applied stress. A maximum stress concentration of approximately 1.2 was measured at the maximum applied composite strain level of 0.5%. This value compared well with existing analytical models.