bluuebunny/crossref_metadata_2025 huggingface dataset:
Radiation Resistance of Advanced Ferritic-Martensitic Steel HCM12A
Authors: Allen TR , Tan L , Tucker JD , Gan J , Gupta G , Was GS , Shutthanandan S , Thevuthasan S
Published: April 2008

HCM12A is an advanced 12 Cr ferritic-martensitic steel designed for higher temperature operation than could be achieved using earlier generation steels such as HT9. HCM12A is one of the advanced alloys under consideration for application in core components in Generation IV nuclear energy systems, and is of particular interest to the supercritical water reactor, sodium fast reactor, and lead fast reactor designs. The radiation resistance of HCM12A has not previously been studied. This work provides information on the hardening and microstructural changes in HCM12A after irradiation using 2.0 MeV protons at 400°C to 10 dpa and 5 MeV Ni-ions at 500°C to 50 dpa. Following irradiation, changes in hardness were measured using Vickers hardness indentation, changes in microstructure and phase stability were studied using transmission electron microscopy, and changes in microchemistry were measured using scanning Auger microscopy. The hardness increases by roughly 70 % and saturates by roughly 5 dpa. The changes to the microstructure contributing to this hardness increase are primarily due to the formation of precipitate phases, with some contribution from changes in dislocation density. Chromium is enriched at grain boundaries prior to irradiation, likely due to grain boundary carbides, and increases further during the irradiation.
Fracture Toughness, Thermo-Electric Power, and Atom Probe Investigations of JRQ Steel in I, IA, IAR, and IARA Conditions
Authors: Nanstad RK , Niffenegger M , Kalkhof RD , Miller MK , Sokolov MA , Tipping Ph
Published: April 2008

The International Atomic Energy Agency has sponsored a number of studies involving a specific plate of A533 grade B class 1 steel designated heat JRQ. In this cooperative study between the Paul Scherrer Institute (PSI) and the Heavy-Section Steel Irradiation Program of Oak Ridge National Laboratory (ORNL), groups of Charpy impact, tensile, and precracked Charpy specimens of the JRQ plate were irradiated by PSI to four different fast neutron fluences [from 0.39 to 5.0 × 1023 n/m2 (>1 MeV)] in a test reactor. Additional specimens were given a post-irradiation thermal annealing treatment at 460°C for 18 h when 50 % of the target fluence was reached, followed by reirradiation to the same target fluences for the four groups of irradiated specimens. Additionally, ORNL thermally annealed some of the reirradiated specimens, as well as some of those in the irradiated only condition. Charpy impact, tensile, fracture toughness, and hardness tests have been performed to evaluate material response in the various conditions and to compare with the unirradiated material. Additionally, thermo-electric power experiments have been conducted by PSI, while atom probe tomography evaluations have been conducted by ORNL. Except at the highest fluence, the results show that the material given an intermediate annealing treatment exhibited irradiation-induced transition temperature shifts about the same as those that were only irradiated. However, the upper-shelf energies were generally higher and the yield strengths were generally lower for the reirradiated groups. The intermediate thermal annealing resulted in less reirradiation embrittlement of fracture toughness than Charpy impact toughness, while annealing after reirradiation resulted in significant increases in Charpy upper-shelf energy above that in the unirradiated condition. Irradiation-induced and IAR Charpy impact transition temperature shifts exhibit a nearly linear correlation with Seebeck coefficient in the 1 and IAR conditions. ORNL has also sent additional specimens from I, IA, IAR, and IARA test of JRQ for additional TEP testing. After irradiation, a high number density of ultrafine Cu-, Mn-, Ni-, Si-, and P-enriched precipitates were observed by atom probe tomography. Phosphorus segregation to dislocations was also observed. A significantly lower number density of larger Cu-, Mn-, and Ni- enriched precipitates was observed after the second annealing treatment.
Effects of Neutron Dose, Dose Rate, and Irradiation Temperature on the Irradiation Embrittlement of a Low-Copper Reactor Pressure Vessel Steel
Authors: Kasada R , Kudo T , Kimura A , Matsui H , Narui M
Published: April 2008

A series of irradiation experiments to investigate the effects of neutron fluence and flux on reactor pressure vessel (RPV) steels has been performed using the Japan Material Testing Reactor (JMTR). The irradiation temperature has been precisely controlled at 290°C within an error of ±2°C during reactor operation. The neutron fluence and flux ranged from 9.3 × 1017 to 1.1 × 1020 n/cm2 and from 1.4 × 1011 to 6.3 × 1011 n/cm2/s, respectively. The material used in the present study was an A533B RPV steel in which the copper and phosphorous concentrations are 0.03 and 0 002 wt%, respectively. Charpy impact test results with one-third sized specimens showed no dose-rate dependence. Microstructural observation revealed that a higher irradiation temperature at around 340°C resulted in formation of rather large dislocation loops and smaller microvoids.
Use of Broken Charpy V-notch Specimens from a Surveillance Program for Fracture Toughness Determination
Authors: Scibetta M , Lucon E , Chaouadi R , van Walle E , Gérard R
Published: April 2008

Broken Charpy specimens from the surveillance program of a Belgian nuclear power plant are used to obtain the fracture toughness in the transition regime using the master curve concept. Two approaches are used. The first one is based on the reconstitution of Charpy specimens that are subsequently precracked and tested in three-point bending. The second approach is an innovative one that makes use of miniature Compact Tension specimens, which are machined from the broken pieces of the original Charpy specimens. Both approaches lead to consistent results. The recently developed miniature Compact Tension design has the advantage to use less material and is less costly in terms of machining operation. For the material investigated in this research, the current regulation, based on a semi-empirical approach to obtain the lower bound fracture toughness, is demonstrated to be conservative as compared to the direct fracture toughness determination.
Atomic-Scale Simulation of Defect Cluster Formation in High-Energy Displacement Cascades in Zirconium
Authors: Voskoboinikov RE , Osetsky YN , Bacon DJ
Published: April 2008

A systematic study of damage in high-energy cascades in Zr with primary knock-on-atom (PKA) energy up to 25 keV has been carried out by molecular dynamics (MD) over a temperature range from 100–600 K. The high number of simulations for each condition of temperature and energy has revealed the wide variety of defect clusters that can be created in cascades. Mobile or sessile, two-dimensional (2D) or three-dimensional (3D) clusters of both vacancy and interstitial type can be formed. The population statistics of clusters of each type and the fraction of vacancies and self-interstitial atoms (SIA) in clusters, were obtained, and their dependence on the temperature and PKA energy were investigated. Both vacancy and SIA clusters can be mobile. However, depending on their type, self-interstitial clusters exhibit one-dimensional, planar, or three-dimensional motions, whereas vacancy clusters of only one type can glide in one dimension only. We have also performed separate MD simulations of some SIA and vacancy clusters to study their thermal stability and possible transformations.
Deformation Mechanism Maps of Unirradiated and Irradiated V-4Cr-4Ti
Authors: Li M , Zinkle SJ
Published: April 2008

This paper addresses various deformation mechanisms of unirradiated and irradiated V-4Cr-4Ti in terms of Ashby-type deformation maps. Tensile tests were carried out in the temperature range of 950–1150°C at strain rates of 10-3, 10-4, and 10-5 s-1. In addition, published tensile data and thermal creep data before and after irradiation were analyzed to provide further information about the materials' deformation behavior. The extensive tensile database for V-4Cr-4Ti was used to determine the key material parameters in physically-based constitutive equations. The resultant constitutive equations were employed to construct the Ashby deformation mechanism maps for unirradiated and irradiated V-4Cr-4Ti. Using the data analysis from the tensile tests, deformation map predictions at slow strain rates were obtained and verified by comparison with the experimental creep results. The methodology was successful in identifying the operating deformation mechanisms for a given temperature, stress, or strain rate condition. The study examines the limitations of extending creep data and analysis into new operating regimes, particularly where different deformation mechanisms are involved. The application of deformation mechanism maps in creep testing and data analysis is discussed.
Microstructure Evolution in ZrC Irradiated with Kr ions
Authors: Gan J , Meyer MK , Birtcher RC , Allen TR
Published: April 2008

The gas-cooled fast reactor (GFR) is one of six concepts for the Generation-IV nuclear energy system. The fuel for the GFR requires both a high heavy metal loading and the ability to withstand temperatures up to 1600°C during a loss of coolant accident. ZrC is among the few potential refractory ceramic materials with necessary properties to be considered as matrix materials for a dispersed carbide fuel. The radiation response of ZrC to high dose and temperature is a critical research need. This work investigated the microstructure of ZrC irradiated with 1 MeV Kr ions to doses of 10 and 30 dpa at 27°C and 10 and 70 dpa at 800°C with a damage rate approximately 3.0 × 10-3 dpa/s. No radiation-induced amorphization was found. A lattice expansion of approximately 7 % was observed for ZrC irradiated to 70 dpa at 800°C.
Uncertainty Analyses on Reference Values of Charpy Impact Test Specimens
Authors: Takagi S , Yamaguchi Y , Usuda T
Published: April 2008

The uncertainties of reference values of specimens, which are used for the verification of the secondary standard Charpy impact test machine, are investigated. To evaluate the uncertainty of the reference values of specimens, the results of the direct verification of the machine and the repeatability of measurement are considered. The uncertainty components estimated from the direct verification are calculated multiplying the uncertainty of each item and corresponding sensitivity coefficient. The repeatability of measurement is estimated from the results of the routine check data of the standard machine. By combining these components, the overall uncertainties of reference specimens are presented at 30, 100, and 160 J levels of absorbed energy.
Analysis of Charpy Impact Verification Data: 1993–2003
Authors: Splett JD , McCowan CN
Published: April 2008

Indirect verification tests used to verify the performance of Charpy impact machines according to ASTM Standard E23 were evaluated by the National Institute of Standards and Technology (NIST), and the data from these tests are collected in a database. The data include the capacity and the pendulum design of the impact machine, the energy obtained for each specimen tested, the reference energy for the specimen lot tested, and the test date. The principal use of this data is to track the performance of individual impact machines. However, the data also provide an opportunity to evaluate existing and proposed requirements for the indirect verification of Charpy impact machines. The results of more than 16 000 verification tests are used to compare the current verification requirements of ASTM Standard E23 with those of ISO Standard 148-2. Discussions focus on the identification of reasonable, practical, and meaningful verification requirements that might be proposed for use in both documents.
Reference Impact Specimens Made from Low Carbon Steel: Report on Production and Use
Authors: Heping L , Xing Z
Published: April 2008

This paper describes a method of producing reference specimens from low carbon steel and reports the results of a national proficiency testing by 45 laboratories. The reference impact specimens of low carbon steel are much cheaper than the traditional ones, and the proficiency testing proved that the specimens are valid for finding out the problems of impact machines. Furthermore, the data showed that an impact machine would represent the similar relative bias at a different energy level of reference specimen, so it is sufficient to use reference specimens with one absorbed energy level to verify impact machines annually.
Impact Characterization of Sub-Size Charpy V-Notch Specimens Prepared from Full-Size Certified Reference Charpy V-Notch Test Pieces
Authors: Lucon E , Puzzolante J-L , Roebben G , Lamberty A
Published: April 2008

To investigate the feasibility of the production of sub-size Charpy reference test pieces, tests were performed on sub-size samples (3 × 4 × 27 mm3) carefully machined from full-size (10 × 10 × 55 mm3) Charpy V-notch certified reference test pieces. The measured absorbed energy (KV) values indicate a highly satisfactory homogeneity of the sub-size specimens. Sub-size specimens were prepared from full-size reference test pieces of 30, 60, 80, 120, and 150 J nominal absorbed energy; and values between 2 J and 7.2 J were obtained, covering almost fully the range of interest for sub-size Charpy tests. A linear relationship is observed between the KV values of sub-size and full-size samples of the same material.
Different Approaches for the Verification of Force Values Measured with Instrumented Charpy Strikers
Authors: Lucon E , Chaouadi R , van Walle E
Published: April 2008

The Charpy test plays a fundamental role in the nuclear field tor evaluating the neutron embrittlement of the reactor pressure vessel, specifically in the framework of the so-called Enhanced Surveillance Approach, developed at SCK•CEN and aimed at extracting as much information as possible from Charpy impact tests performed with an instrumented striker. Careful analysis of the instrumented force/deflection traces allows defining important parameters which can help investigate material characteristics such as flow properties, microcleavage fracture stress, crack arrest behavior and alternative characteristic (index) temperatures. For this advanced approach to be successfully applied, confidence in the quality of instrumented force values must be high; as a consequence, extensive research has been performed in order to establish an optimal procedure for the verification of instrumented Charpy strikers. Various approaches will be described in this paper and their applicability and effectiveness discussed. A procedure based on the comparison between yield stresses measured from tensile tests and calculated from instrumented Charpy curves has recently been adopted at SCK•CEN as the recommended in-house procedure for verifying instrumented strikers. This method has shown that for all strikers investigated, the so-called “dynamic” calibration (based on the equalization of dial and calculated energies) yields the most accurate results.
An Overview of Fundamental and Simulative Performance Tests for Hot Mix Asphalt
Authors: Zhang J , Brown ER , Kandhal PS , West R
Published: April 2008

Numerous fundamental and simulative test methods are being used to evaluate the performance of Hot Mix Asphalt (HMA). Permanent deformation, fatigue cracking, thermal cracking, loss of surface friction, and stripping are the five main distress types for HMA pavements. All of these distresses can result in loss of performance, but rutting is the one distress that is most likely to be a sudden failure as a result of unsatisfactory HMA. Other distresses are typically long term and show up after a few years of traffic.

This paper provides a general overview of the fundamental, empirical, and simulative tests for HMA corresponding to each of these five distresses. All test methods have been evaluated in terms of advantages and disadvantages. However, major emphasis has been placed on tests for evaluating permanent deformation.
Simulative Performance Test for Hot Mix Asphalt Using Asphalt Pavement Analyzer
Authors: Kandhal PS , Cooley LA
Published: April 2008

Permanent deformation, or rutting, has been and continues to be a problem in the performance of hot mix asphalt (HMA) pavements. This paper presents a summary of work conducted under National Cooperative Highway Research Program (NCHRP) Project 9-17. This research project was undertaken to evaluate the Asphalt Pavement Analyzer (APA) to determine its suitability as a general method of predicting rut potential. There was a need to identify test conditions within the APA that produced results most related to field rutting performance. Ten HMA mixes of known field rutting performance were tested within a full factorial experiment designed to determine the combination of testing conditions for the APA that best predicts field rutting. The experimental plan consisted of different specimen types (beam and cylinder), air void contents in compacted test specimen (4 and 7 %), hose diameters (25 and 38 mm), and test temperatures (high temperature of standard PG grade based upon climate and 6°C higher temperature). Based upon the test results and analysis, a tentative standard method of test was developed and recommended. A standard practice for establishing maximum specified rut depth for APA by highway agencies has also been recommended.
Field Validation of Superpave Shear Test on NCAT Test Track
Authors: Zhang J , Xie H , Kandhal PS , Powell RD
Published: April 2008

When the National Center for Asphalt Technology Test Track was built in 2000, one of the primary objectives was to determine the ability of a number of laboratory tests to predict the permanent deformation of various mixtures. Repeated Shear at Constant Height (RSCH) was included as one of the tests in the laboratory study. The subject of this paper is field validation of the Superpave Shear Tester (SST) based on the field rutting data from the Test Track. Permanent shear strain, slope of the deformation rate, repetitions to a certain strain level, and shear modulus were the parameters evaluated for RSCH. The sensitivity of SST test to asphalt binder type in the various test track sections was analyzed. The relationship between RSCH test results and field rut depth was poor. This was partly due to the good quality of the track construction, thick pavement structure, and mild summers during the loading of the 2000 track, which did not cause any significant rutting. The sensitivity study indicated that PG 76-22 binder performed better than the PG 67-22 binder in the RSCH test. The criteria developed by the Asphalt Institute seem to be in a reasonable range.
C-φ Characterization Model for Design of Asphalt Mixtures and Asphalt Pavements
Authors: Fwa TF , Tan SA
Published: April 2008

This paper reports the results of a research effort initiated in the early 1990s to develop a C-φ (cohesion-angle of friction) characterization model for the design of asphalt mixtures and asphalt pavements. It is demonstrated that, since the model is based on the fundamental material properties represented by C and φ, it can derive analytically other asphalt mix design parameters such as Marshall stability and flow, and indirect tensile strength. The C-φ characterization model therefore offers a useful basis for the development of a comprehensive design framework that integrates asphalt mix design with asphalt pavement structural design. To demonstrate this capability, the research developed an empirical-mechanistic rutting prediction model of asphalt pavement layer using the C-φ characterization model. In addition, the model allows stresses and strains under design loading to be computed, which can be applied as input to structural analysis for asphalt material selection and pavement thickness design.
Identification of a Physical Model to Evaluate Rutting Performance of Asphalt Mixtures
Authors: Drakos CA , Roque R , Birgisson B , Novak M
Published: April 2008

The objective of this study is to identify a physical model that can provide reliable predictions about a mixture's ability to resist permanent deformation under realistic stress states. Key differences were identified between stress states under the existing Asphalt Pavement Analyzer (APA) loading device (hose) and stress states under radial truck tires, which may indicate potentially different rutting mechanisms. It was shown that the APA hose was not capturing the critical lateral stresses found to be detrimental to rutting and cracking of HMA pavements. A new loading device (rib) was designed and constructed for use in the APA that more closely represents stress states found under radial tires.

Contact-stress measurements under the two loading devices — hose and rib — showed that the rib was able to reproduce the lateral stresses found under individual ribs on a radial-tire tread. Subsequent finite element modeling also showed that the rib appeared to generate similar shear stress patterns to those found under the modeled radial-tire load.

A new method was developed to measure deformations on the surface of APA specimens, where a contour gauge was used to record and store the entire surface profile of the sample throughout the progress of the test. An area-change parameter, which reflects volume change, was introduced to calculate the volumetric changes in the specimen. The area-change parameter can be used to determine whether specimen rutting is primarily due to shear instability or consolidation.

Two mixtures of known field performance — poor and good — were tested to evaluate the test's ability to predict performance with the new loading device and the new measurement and interpretation system. Results showed that the new system (loading strip and profile measurement method) appears to have greater potential of evaluating a mixture's potential for instability rutting than the original (hose and single rut-depth measurement) configuration.
Water Resistance and Vapor Permeance of Weather Resistive Barriers
Authors: Butt TK
Published: April 2008

Weather-resistive barriers (WRBs) are typically used in exterior walls of low rise frame buildings under claddings such as stucco (cement plaster), wood and wood derived products, vinyl (PVC), and masonry veneer. WRBs are primarily intended to provide resistance to water that may penetrate the outer cladding. WRBs also provide resistance to passage of air to varying extents but generally are moderately permeable to water vapor. Traditional WRB materials were limited to asphalt saturated felts and papers, but polymeric sheets have taken a growing share of the market in recent years. There are also trowel-applied and rigid board WRBs. Little information is available about the comparable properties of commercially available materials or what to consider when selecting the appropriate product for a particular application. Both building code requirements and vendors' product information are inconsistent and confusing. This paper, which is limited to the properties of water resistance and water vapor permeance, provides information that may be helpful in understanding, selecting, and using weather resistive barriers.
Adhesive Characterization & Durability of Self-Adhered Flashings
Authors: Katsaros JD
Published: April 2008

Self-adhered flashing products can very effectively maintain a durable moisture-tight seal at the window-wall interface, which is highly vulnerable to moisture intrusion. However, it is essential that these products be installed under conditions where adequate adhesion to the substrate is achieved. Also, the self-adhered flashing products must have thermal durability and dimensional stability to maintain their performance at the high temperatures that can exist behind siding. This study gives a preliminary adhesion characterization assessment of six self-adhered flashing products, three with modified-asphalt based adhesives and three with butyl based adhesives, onto several common building substrates and installed at a range of temperatures, including moist and dusty conditions. What is found is that the butyl based adhesive systems have a broader window of installation surface conditions and temperatures where “adequate adhesion” is achieved without the use of a primer than the modified-asphalt based adhesive products. Also, a thermal aging study shows that the butyl based adhesive products are more thermally stable than the modified-asphalt based products at typical temperatures behind siding. Also, film topsheets are more prone to deformation and curling after thermal aging than nonwovens composite or foil laminate based topsheets.
Designing and Specifying Self-Adhering Flashings for the Window-Wall Interface
Authors: Batemam R
Published: April 2008

Self-adhering flashings provide a flexible and durable material that conforms to various wall planes, particularly those occurring in recessed wall openings. New flashing methods for the window-wall interface are available for this material. These new methods for designers are illustrated with step-by-step installation details for recessed windows, flush wall openings, recessed sills, and sill pan flashings. Considerations for flashing the window-wall interface are presented. A guide specification for self-adhering flashings is included for specifiers.
Effect of Installation Details on the Condensation Performance of Window Frames
Authors: Kudder RJ , Babich SK , Johnson DK
Published: April 2008

Industry standard tests and calculation methods under laboratory conditions are used to determine a Condensation Resistance Factor (CRF) for window frames. The CRF is one of several performance parameters used to select fenestration products for specific conditions of exposure and occupancy. Colder climates and higher interior humidity typically require fenestration products with higher CRFs. The CRF by itself is not necessarily a predictor of the ability of a window frame to resist interior surface condensation due to thermal bridges or breaches in thermal breaks created by installation details, rough opening materials, and surrounding wall details. This paper explores the affect of installation details on the interior surface temperature of metal window frames, and indirectly, the likelihood of surface condensation on the frame.
Review of Specific Local Fenestration Units, Building Envelope Interface Practices, and Materials Compared to ASTM E 2112, Current Acceptance Criteria, and Evaluation Practices.
Authors: Ackerman DS
Published: April 2008

1. Variations in physical installation environments

a. Weather variations in Washington

b. Types of construction and materials used

c. Weather impact on interface materials and exposure periods

d. Installation practices during varying conditions

2. Installation of windows and flashing in single and multifamily projects in the Northwest

a. Divergence of methods between locations and type of construction

b. Agency requirements and inspections

c. Architect construction plan specifications

d. Practice compared to window manufacturers and E2112 specifications

e. Common Installation Problems Caused By Window Installers

f. Practical considerations, standards vs. the real world

f. Window manufacturer's instruction, guidance and training

h. Flashing observations encountered in the development of a new product

3. Consideration of current Acceptance Criteria and Evaluation Reports
Lubrication Characteristics on Sliding Surfaces in a Piston Pump and Motor During Running-In Tests
Authors: Tanaka K , Kyogoku K , Nakahara T
Published: April 2008

Lubrication characteristics on the sliding surfaces between piston and cylinder in a piston pump and motor with running-in have been investigated. The friction characteristics on the sliding surfaces of the friction test machine have been examined with the use of pin-on-V-block before running-in tests. The running-in tests with model apparatus of the piston pump and motor have been carried out under the mixed lubrication condition in the Stribeck curve. The running-in condition was chosen after considering parameters such as friction force, separation voltage and roughness. In these parameters, friction force and separation voltage have played an important role for the evaluation of effective running-in. It is clarified that the rate of running-in of the cylinder is lower than that of the piston. The effects of the piston top profile and stiffness of the piston on the lubrication characteristics have been studied.
Wear Particle Analysis
Authors: Poley J
Published: April 2008

Many industrial plants feature varieties of gearboxes and hydraulic systems that are amenable to lube analysis monitoring, in addition to vibration testing. Typical ‘basic’ packages, however, don't always provide a window to fully assess machinery condition. One reason is because medium to slow speed rotating units often do not generate very small [<5microns] wear particles proportionate to large. If the large particles are not monitored, failure may occur without prior warning, if only basic lube analysis is in use. Wear particle analysis, e.g., ferrography, on the other hand, addresses these larger particles. In the case of ferrography or patch analysis, microscopic analysis is available to observe particles directly. Pictures can be taken, as well, as visual support of the Evalutor's conclusions.
Hydraulic Pump Contaminant Wear
Authors: Tessmann RK , Hong IT
Published: April 2008

The contaminant wear of any pump depends on the operational and the contaminant severity as well as the inherent contaminant sensitivity of the pump. In order to evaluate the contaminant sensitivity of a pump it is necessary to conduct a carefully controlled test. The primary result obtained from this test is a lumped parameter called the contaminant wear sensitivity coefficient, which represents the degree of contaminant tolerance.

A contaminant sensitivity theory has been developed which states that for every contaminant particle that passes through a pumping chamber, the pump looses a finite portion of its flow delivery potential. The degraded flow rate equals the sum of the product obtained by using both the wear sensitivity coefficient and the particle exposure rate for all particles sizes to which the pump has been exposed. The wear sensitivity coefficient is simply the volume of the pumping potential that the pump looses per particle exposed. The particle exposure rate equals the product of the flow rate and the particle concentration in the fluid.

An analytical treatment of the contaminant sensitivity concept is called the Omega Theory. This paper first reviews the contaminant sensitivity test and discusses the various test parameters. In addition, the paper presents the analytical model that permits computer techniques to be applied in deriving and manipulating contaminant sensitivity coefficients obtained from testing in order to construct the contaminant tolerance profile (Omega Life) and calculate the service life for a specific pump. Furthermore, the paper provides a means by which the field service life can be estimated based upon the standard test.
Research of Suitable Material Pairs for Applications Operating with High WaterBased Fluids
Authors: Oberem R , Murrenhoff H
Published: April 2008

Using high water-based fluids in a hydraulic system requires the application of other materials than in oil hydraulic facilities. High water-based fluids have a content of water not under 80%. The rest is a HWBF concentrate. The content of water defines the features of the liquid. Because of the low viscosity of a high water-based fluid, the loading of the surfaces in water hydraulic systems is much higher than in a machine operating with oil. The low viscosity produces smaller gaps in tribological contacts. It is possible that the surfaces of a tribological contact will not be separated. The problem of adhesive and abrasive damage is increased. The selection of a suitable material pair for a tribological contact is especially important. To substitute a material in a pump or in a motor directly by another material requires great efforts and may become very lengthy and expensive.

IFAS is concerned with the development of a hydrostatic transmission operating with high water-based fluids. The goal of the project is to design and construct a constant displacement motor and a pump with a variable displacement volume based upon the swash plate principle for pressures up to 315 bar. In order to achieve the goal specially coated material pairs and their surface finish have to be tested with the objective of decreasing friction and wear. To reduce the expense of testing, the selection of materials is conducted with a special model. Two ring-shaped test bodies are pressed against each other by a hydraulic cylinder. One of the test bodies is rotated. Both test bodies are flushed by a high water-based fluid. Under different loadings and with different velocities of rotation the friction coefficient and the wear of different material combinations were established. Conventional materials, plastics, PVD coatings, and ceramics were tested. To verify the positive results obtained in the model, one of the materials which was classified as suitable is tested in a swashplate unit.
Ceramic Parts for Hydrostatic Pumps and Motors
Authors: Feldmann DG
Published: April 2008

This paper deals with the development of ceramic parts in hydrostatic machinery as the result of a research project, whose purpose was to demonstrate the potential improvement of ceramics. The properties of ceramics, how to use them in hydrostatic machines, and the differences in the design approach compared to the design of metal parts will be shown. The lack of material data for ceramics was resolved by developing a test method and specimens that reproduced the load and stress conditions of the component parts. Test results with respect to endurance life and change of machine efficiency are also reported. An outlook for work in the future will be given at the end.
An Investigation of Fundamental Blistering Phenomena in Rotary Lip Sealing
Authors: Schulz F , Wollesen VM , Vötter M
Published: April 2008

New investigations concerning the blistering phenomenon in rotary lip sealing have been carried out with fluoro elastomer seals with and without epidermoid layers, using different oil types and seals in different arrangements under static and dynamic conditions, including a microscopic analysis.

The test results indicate that blistering in rotary lip sealing is not only a problem of fluid compatibility but strongly refers to the thermal and mechanical load of the seal in contact with the rotating shaft. Blister-filling may be achieved in a macroscopic way without adsorption and diffusion of the sealed fluid.

This work examines the role of important factors of a blister formation in rotary lip sealing and therefore helps to analyze and prevent blistering in practical applications.
The Importance of Shear Stability in Multigraded Hydraulic Fluids
Authors: Hyndman CW , Kinker BG , Placek DG
Published: April 2008

Multigrade hydraulic fluids are known to undergo loss of viscosity during service. The mechanism is a function of severe shear forces generated in high pressure operations, which affect polymeric Viscosity Index Improvers (VII) present as additives. The level of shear degradation experienced is related to several factors: the molecular weight and chemical structure of the polymer, the pressure drop and physical design of the hydraulic system, and fluid temperature. Viscosity Index Improver polymer molecular weight will determine thickening power, but also impact the critical parameters of shear stability and low temperature viscometrics.

New data generated in a Sundstrand axial piston pump test stand provide further insight into the relationship between polymer molecular weight and shear stability.

Previous field test work has documented operating conditions encountered by multigrade hydraulic fluids in forestry equipment. The shear stability data gathered in this study can be used to predict fluid performance in high-temperature field applications.
Recent Experiences with Ester Based Fluids in Qualification Tests
Authors: Feldmann DG , Kessler M
Published: April 2008

To develop a new, for instance a biodegradable hydraulic fluid numerous standard and in-house screening tests are necessary to verify the lubricating properties. It was further determined that evaluation within a hydrostatic transmission, simulating field operating conditions, as a final test is critical but needed, as new fluids will occasionally fail this test, although all prior tests were passed.

This paper describes recent experiences at the authors' institute with ester based hydraulic fluids run in a heavily loaded hydrostatic transmission under laboratory conditions on the so-called “flywheel-test rig” [1–6]. Change of fluid properties and wear behavior of the hydrostatic components are compared to derive statements about the fluids' behavior to be expected in the field application.
Autofrettage to Offset Coefficient of Thermal Expansion Mismatch in Metal-Lined Composite Pipes
Authors: Barbero EJ , Wen EW
Published: April 2008

Coefficient of thermal expansion (CTE) mismatch between metal and composite is a major barrier for use of composites in applications that require a metal liner. The situation is critical for cryogenic applications because of the large temperature excursion to which the pipe is subjected. The paper demonstrates that CTE mismatch can be offset through the use of autofrettage. Modeling techniques are introduced for the analysis of conventional mechanical autofrettage. Novel thermal autofrettage is proposed and demonstrated to be effective for those situations and material combinations for which conventional autofrettage is not feasible.
Non-Scalar Approach to Simulate the Mechanical Degradation Process in Fibre-Reinforced-Polymers (FRPs)
Authors: Gagel A , Schulte K
Published: April 2008

A non-scalar formulation of the mechanical degradation process in FRPs is proposed. The approach bases on understanding the complex degradation process of a dynamically loaded FRP as a curve in a K-dimensional space. Each dimension of this space represents one type of observable physical damage (e.g., transverse crack formation and delamination) or one empiric damage parameter (e.g., damage according to Miner's rule). All points on the curve — or all stages of the damage process — are described unambiguously by a K-dimensional array D. Each component of D ascends monotonically with the applied load. By choosing summable parameters for the components of D and by breaking down the load into incremental load changes ΔL this non-scalar approach enables the damage growth with an applied load to be described in terms of numerical methods for evaluation and simulation. Furthermore, the proposed description allows to utilise a physically based damage accumulation hypothesis for dynamically loaded FRPs and to account for the interactions between different types of damage.
Assessment of Damage in a Unidirectional Off-axis Carbon-Epoxy Composite Under Cyclic Loading
Authors: Sorenser LK , Plumtree A
Published: April 2008

Cyclic tests were conducted on unidirectional HTA/6376 specimens in order to isolate and describe the degradation of an off-axis composite, resulting in matrix dominated failure. Specimens were loaded at 45° to the fibre axis and tested first under quasi-static conditions and then under tension-tension fatigue. Resulting stress-life curves for the 45° off-axis carbon fibre-reinforced epoxy were shallow, resulting in a large amount of scatter.

Damage was monitored using strain gauge rosettes in the loading and transverse directions, as well as perpendicular to the fibres. Hysteresis loops were described by different definitions of modulus and strain accumulation, thus providing models based on dynamic, cyclic creep and total fatigue damage. Although the cyclic creep model described damage, including that in the first cycle, the total fatigue modulus is preferred based on its ability to collapse all damage curves into one. Use of this master curve permits accurate prediction of fatigue lives.
Injuries in Norwegian Ski Resorts 2002 – 2004
Authors: Ekeland A , Rϕdven A
Published: April 2008

A central ski patrol-based registration of skiing and boarding injuries was performed by the Norwegian Ski Lift Association during the winter seasons 2002/2003 and 2003/2004. Totals of 7252 injured skiers/boarders and 4.884 million skier/boarder days were recorded during the two seasons, giving an injury rate of 1.5 injured per 1000 skier/boarder days. Most of the injuries occurred during alpine skiing (49 %) and snowboarding (43 %), whereas telemark skiing and skiboarding each accounted for 4 % of the injuries. Wrist injuries were common among injured snowboarders (28 %) compared to only 6 % for skiboarders and 4 % each for alpine and telemark skiers (P<0.001). The knee was the main injury location in alpine skiers (25 %) compared to 19 % among skiboarders, 12 % among telemarkers, and only 7 % among snowboarders (P<0.001), but the percentage of knee injuries was almost twice as high for females compared to males, both in skiers and snowboarders (P<0.001). As percent of all injuries, injured snowboarders suffered more fractures (35 %) than skiboarders (30 %), telemark (24 %) and alpine skiers (22 %) (P<0.001), but fracture of the lower leg was uncommon among snowboarders (1 %) and telemarkers (2 %) compared to alpine skiers (7 %) and skiboarders (15 %) (P<0.001). Lower leg fractures accounted for 4 % of the injured alpine skiers 20 years and older and adolescents aged 13–19 years compared to 15 % for children 12 years and younger (P<0.001). Nineteen percent of the skiers/boarders were injured in snowboarder parks, and these injuries were more severe than those occurring at other locations. In conclusion, injured alpine skiers were most prone to knee injuries, and skiboarders to lower leg fractures. This fracture was still a common injury for children in these two disciplines. Injured snowboarders were most prone to suffer wrist injuries. The percentage of knee injuries among females was almost twice that of males both in skiers and snowboarders. Injuries sustained in snowboarder parks were more severe than other injuries on the slope.
Reduce the Injuries, Change the Culture: Insights from Telemarking
Authors: Dickson TJ
Published: April 2008

Risk management theory suggests that a proactive approach rather than a reactive approach is more effective for managing risks. In the context of snowsports this would mean that a whole-of-industry approach to snowsport injury prevention would range from the images in brochures, the organizations in the industry through to the equipment and people (staff and participants) involved in the industry. Telemark skiing has experienced a resurgence in interest, after 100 years of existence, correlating with changes in the availability and design of telemarking equipment. This paper will build on insights from a survey of Australian telemark skiers through a review of literature from occupational health and safety, risk management for outdoor pursuits, and organizational culture to reflect upon the need for a wholistic and strategic research agenda to aid in the reduction of snowsport injuries.
Arthroscopic Treatment of the First Anterior Shoulder Dislocation in Young Skiers
Authors: Yiannakopoulos CK , Zacharopoulos AN , Antonogiannakis E
Published: April 2008

The purpose of this paper was to describe the results of arthroscopic shoulder stabilization in skiers following the first episode of anterior dislocation. Between 1999 and 2001, 18 patients aged 19–27 years were treated arthroscopically following an acute, primary anterior shoulder dislocation. All patients were active skiers and were injured during skiing. The detached anterior labrum was reattached on the glenoid articular surface using 2–5 bone anchors, mainly metallic. Postoperative evaluation was performed with the Rowe-Zarins scale with a mean follow up of 31 months. There have been no recurrences and all patients returned to their preinjury level. According to the Rowe-Zarins scale the outcome was excellent in 15/17 cases. Arthroscopic shoulder stabilization in selected, active patients provides good mid-term functional results. The quality of glenohumeral ligaments was better compared to patients with chronic instability and the secondary injuries were less common.
The Metabolic Syndrome and Male Infertility
Authors: Kasturi Sanjay S. , Tannir Justin , Brannigan Robert E.
Published: April 2008

ABSTRACT: Metabolic syndrome (MetS) is highly prevalent, affecting more than 47 million US residents. This condition is also multifaceted, potentially leading to significant disturbance of numerous physiologic processes. This review article evaluates the literature regarding metabolic syndrome and male reproductive health. Links between obesity, dyslipidemia, hypertension, and insulin resistance are each examined with regard to their associated detrimental effects on male fertility. At the end of this manuscript, we propose a new MetS/male infertility paradigm. Additional studies specifically addressing the components of MetS and their impact on male reproduction will enhance our understanding of the underlying pathophysiology. These studies may also help clarify the role for therapeutic intervention.
Environmental Erectile Dysfunction: Can the Environment Really Be Hazardous to Your Erectile Health?
Authors: Burnett Arthur L.
Published: April 2008

ABSTRACT: The proposal that exposures to environmental or occupational substances may affect erection ability is a tenable one and would add to a growing list of pathogenic risk factors associated with erectile dysfunction. Several lines of evidence gained by clinical epidemiologic and biomedical research investigations lend support. Several environmental toxicants to include lead, organic solvents, and pesticides have been implicated as possibly hazardous agents. Effects on the nervous and hormonal systems have been proposed as the leading mechanisms by which environmental toxicants adversely impact erectile function. Synthesis of the current evidence supports a possible risk association between environmental exposures and erectile dysfunction. However, scientific support is lacking to establish a direct causal association at this time. More scientific work is needed to identify specific environmental agents that may harm erectile function and define their exact mechanisms of action in this regard.
Targeting the Hedgehog Signaling Pathway with Small Molecules
Authors: Kiselyov Alex S.
Published: April 2008

In addition to the potential stem cells offer for regenerative medicine, they also rapidly are becoming a center of focus in oncology. There are several developmental pathways that are involved in the deregulated signaling in stem cells resulting in tumorigenesis. For example, aberrant activation of the Hedgehog (Hh) pathway has been associated with numerous malignancies including basal cell carcinoma, medulloblastoma, prostate, pancreatic and breast cancers. In vivo evidence suggests the antagonism of excessive Hh signaling may provide a route to unique mechanism-based anti-cancer therapies. This review summarizes recent developments in targeting cell-surface proteins and intracellular targets from the Hh pathway with small molecules. Hh signaling is triggered by lipid-modified Hh proteins that exert their activity via a series of transmembrane receptors (Patched, Ptc and Smoothened, Smo). Smoothened (Smo) is a 7-TM protein reported to be the most druggable target in the Hh signaling cascade. We further review several published programs geared towards identification and profiling of synthetic antagonists of Smo. Challenges and perspectives of this approach are also discussed.