bluuebunny/crossref_metadata_2025 huggingface dataset:
The Relationship Between Chronic Values in Toxicity Tests with Ceriodaphnia Dubia
Authors: Zuiderveen JA , Birge WJ
Published: March 2009

Chronic toxicity tests using Ceriodaphnia dubia are conducted across the United States by facilities releasing wastewaters into bodies of freshwater, as well as by the appropriate agencies governing environmental protection. Until recently, the chronic values used for decision making were the “No Observable Effect Concentration” (NOEC), the “Lowest Observable Effect Concentration” (LOEC) and the “Chronic Value” (ChV). Currently, “Inhibition Concentrations of a Given Percent” (ICp) are being considered, for effluent permitting, by a number of states. The ICp value is the concentration at which the reproduction of C. dubia is inhibited by “p” percent. It has been asserted that the IC25 is approximately equivalent to the NOEC and that the IC50 is similar to the ChV. Using data collected in a series of chronic toxicity tests, these values were compared. The results came from 3-brood Ceriodaphnia Survival and Reproduction tests that had been performed with 10 different metal cations. Results showed that the IC25 values were similar to the NOEC, LOEC and the ChV. However, the IC25 correlated best with the ChV, having only 7 (28%) of the values differing by more than 20%. In contrast, the LOEC and NOEC had 12 (48%) and 18 (72%) values, respectively, that were not within 20% of the IC25. Likewise the LOEC and IC50 were most comparable to each other, with only 2 (8%) values differing by a factor of two or more, while the ChV had 9 (36%) and the NOEC had 12 (48%) such values. Finally the IC10 was the most similar to the NOEC for these experiments, with only 6 (24%) values differing by more than 20%. This implies that the more recent philosophy of regulating to the IC25, instead of the NOEC, may not be as protective of aquatic life, if the wastewater contains metals.
Comparison of Methods to Standardize ASTM C 1199 Thermal Transmittance Results
Authors: duPont WC
Published: March 2009

ASTM C 1199-91 requires that the measured air-to-air U-factor, US, is standardized to the U-factor that the test specimen would have if it was tested with standardized surface conductance coefficients on both sides. This produces the standardized thermal transmittance, UST, which is typically a smaller value than the thermal transmittance (the air-to-air U-factor), US. ASTM C 1199-91 currently allows for two methods of determining standardized thermal transmittance, and this paper proposes a variation of one of those methods. In addition this paper compares the results from all three methods of standardization using actual test results from five NFRC accredited testing laboratories. By standardizing the measured thermal transmittance, the results from different laboratories that may have different wind machines and thermal chamber configurations can be directly compared. In addition, the test results can be directly compared with computer simulation results that have also been determined using standardized surface heat transfer coefficients. This latter point is critical to the National Fenestration Rating Council’s certified product validation program. This paper recommends that the proposed method of determining the standardized thermal transmittance replace one of the existing methods, and that there be a criteria established that clearly identifies which of the two methods of calculating the standardized thermal transmittance is to be used when testing different fenestration products.
Non-Destructive In-Situ Determination of the Rare Gas Content of Highly Insulating Glazing Units
Authors: Gross J , Fricke J
Published: March 2009

For a drastic reduction of heat transfer in glazing units low emissivity coatings and filling gases with low thermal conductivity, e.g. argon, krypton or xenon, are used. As the rim seal is not perfectly leak tight, part of the filling gas may diffuse out and air could diffuse into the spacing, resulting in a deterioration of the insulating performance. By measuring the sound velocity in the gas filling the relative amount of the noble gas can be determined. A theoretical expression for the sound velocity of an air-argon mixture is experimentally verified to 0.5%. In order to determine the krypton or xenon content to within about 10%, the sound velocity is determined by measuring changes of the travel time and the glazing spacing instead of absolute values. A change in spacing is achieved by pressing ultrasonic transducers onto the glazing unit with varying force. A sound frequency of typically 1 MHz is used for experiments carried out on a 50 × 50 cm2 argon filled double pane glazing with a spacing of 14 mm. The expected change of sound velocity with gas composition is analyzed with respect to the loss of thermal performance of the glazing. For xenon and krypton the effective U-value of the glazing can be determined from the ultrasound measurement with an uncertainty of better than 0.04 W m-2 K-1, whereas for argon the uncertainty with the present setup is acceptable only for higher air content of the glazing.
The Design and Fabrication of a Calibrated Hot Box Apparatus
Authors: Gatland SD , Goss WP , Curcija D
Published: March 2009

A second generation research calibrated hot box was designed and constructed at the University of Massachusetts's Building Energy Research Laboratory. The hot box was built to meet the test methodologies specified in the American Society for Testing and Materials (ASTM) Standard Test Methods C 976 [1] for calibrated hot boxes and C 1199 [2] for fenestration system hot box test methods.

The hot box has the capability of simulating both parallel and perpendicular weather side wind directions on building assemblies, including fenestration (window and door) systems. The weather side chamber has a temperature range of -23.3 °C to 60 °C (-10 °F to 140 °F) and the room side chamber has a temperature range of 21.1 °C to 60 °C (70 °F to 140 °F). The design, fabrication, and instrumentation are described in detail.
Expanded Polystyrene Board as a Standard Reference Material for Thermal Resistance Measurement Systems
Authors: Zarr RR
Published: March 2009

Thermal conductivity measurements at room temperature are presented as the basis for certified values of Standard Reference Material 1453, Expanded Polystyrene Board. The measurements have been conducted in accordance with a randomized full factorial experimental design of two variables, bulk density and temperature, using the National Institute of Standards and Technology one-meter line-heat-source guarded hot plate. Uncertainties of the measurements, consistent with current international guidelines, have been prepared. The thermal conductivity measurements were conducted over a range of bulk density of 37.4 to 45.8 kg/m3 and mean temperature of 281 to 313 K. Statistical analyses of the physical properties of Standard Reference Material 1453 are presented and include variations between boards, as well as within board.
Thermal Imbalance in Hot Box Apparatus and In-Situ Measurements
Authors: Bisiol B , Campanale M , De Ponte F , Moro L
Published: March 2009

Starting from the measurement principle for the determination of thermal resistance of a building element in the laboratory (guarded hot box method) and in-situ, possible testing errors are considered, in particular those due to temperature nonuniformity and imbalance between the metering and guard section. Almost all in-situ measurements are carried out in non-steady-state conditions, nevertheless imbalance problems are similar to those of such steady-state test methods as the guarded hot box.

Temperature non-uniformity on the surfaces of the specimen generates an uncertainty in the definition of the surface temperature itself, but, as a consequence, there is an associated potential temperature imbalance.

The scope of this work is to verify the semi-empirical expressions introduced in two documents of the European Committee for Standardization (CEN, Comité Européen de Normalisation) with those for guarded hot plate apparatus, analytically obtained and experimentally verified by Woodside and those analytically obtained for guarded hot box apparatus. Next, the application of the CEN expression to assess the effect of temperature non-uniformities was checked: for this purpose some homogeneous and layered structures have been analysed by the finite difference method.
Comparison of Experimental and Analytical Methods to Evaluate Thermal Bridges in Wall Systems
Authors: Desjarlais AO , McGowan AG
Published: March 2009

Twelve ASTM C0236 guarded hot box experiments have been performed on wall systems containing a variety of thermal bridges. All of the wall systems included steel framing. Six walls also had a concrete block wall system and a concrete slab to simulate a wall/floor intersection. Thermal bridges included in the wall systems included steel studs, steel tracks, steel stud/track joints, fasteners (steel framing system), concrete slab, metal bolts and angle iron, and brick ties (concrete block wall).

Two-dimensional finite difference modelling was also employed to characterize the wall systems. The experimental test data was used to tune and ultimately validate the computer simulation model. The average variation between the tested and simulated wall system R-Values was 3.3% and ranged from -3.4 to +7.4%. The model was then used to determine the thermal impact of each individual thermal bridge.

Beside the standard complement of temperature sensors that are traditionally used for these laboratory experiments, additional sensors were installed near each thermal bridge to define the area and magnitude of the thermal distortion caused by the thermal bridge. These thermal bridges were analytically simulated and the additional heat flux due to each thermal bridge was computed.

This paper summarizes the experimental and analytical analyses used to characterize the wall systems and concentrate on the thermal impact each type of thermal bridge has on the overall performance of the wall systems.
In Situ Measuring of Thermophysical Properties of Building Materials and Wall Configurations
Authors: Dreyer JW
Published: March 2009

The thermal properties of building materials are of great importance for many technical questions. The thermal insulation characteristics of external wall constructions decisively determine the utility value and the running costs in housing and public buildings. In this paper possibilities are represented to record such values by means of in-situ-measurement. A measurement arrangement is introduced to determine the thermal resistance of external wall structures and/or the thermal conductivity of material layers. This method works with a heating system transmitting a definite steady heat flux through the objects. The generated temperatures determine the thermal resistance and the thermal conductivity. When a periodical intermittent heat flux is generated, the storage capacity or the specific heat can also be determined. To measure the thermal properties of each layer of multilayered constructions, like thermal conductivity, thermal diffusivity or specific heat, it is advantageous to use temperature and flux gradients existing there in according to the prevailing initial- and boundary-conditions. To gain knowledge of mentioned gradients, temperature sensors are being placed among all layers of different depths. Additionally the heat exchange occurring across the surface has to be measured by means of heat flux transducers. Temperature measurements are taken at certain points in the space-time-grid underlying the given construction to enable the description of the thermal development. By making use of mathematical approaches the course of temperature is described in the form of space-time-functions of polynomial character. The application of fundamental laws allows the user to gain exact knowledge of thermal material properties. This method has been applied to numerous practical cases and it was found to satisfy our expectations, finally enabling the user to investigate deeper into the complexity of building materials and constructions.
A Variability Study on the ASTM Thin Slicing and Scaling Test Method for Evaluating the Long-Term Performance of an Extruded Polystyrene Foam Blown with HCFC-142b
Authors: Fabian BA , Graves RS , Hofton MR , Yarbrough DW
Published: March 2009

The ASTM accelerated aging test method for unfaced foamboard insulation that is based on slicing and scaling has been used on an extruded polystyrene product blown with HCFC-142b. The test method including specimen preparation was carried out at three laboratories. The participating laboratories used different means to prepare thin test specimens. Thin slices of foamboard with and without surface skins were tested in order to assess the effect of skins on the aging process.

Measured values for the apparent thermal conductivity, ka, were used to calculate time average ka for life-times of 10, 20, and 40 years. The time-average ka, from the three laboratories differed by less than 2.5% for 1.5-inch-thick product and less than 2% for 2.0-inch-thick product. The ka for slices with skin on one surface were less than ka of slices of the core foam.
A Review of Expanded Polystyrene (EPS) Properties, Performance and New Applications
Authors: Greeley TR
Published: March 2009

For over thirty years expanded polystyrene (EPS) insulation products have been utilized and accepted by the construction industry as cost effective insulation for roof, wall and foundation applications. During the last several years a number of innovative applications utilizing EPS have been developed which provide creative and cost effective solutions for a variety of residential construction and civil engineering applications.

Residential construction has been dominated by wood stud building technology for over a 150 years. In the past ten years energy and resource conservation requirements and issues within the lumber industry have prompted renewed interest in alternative construction technologies. The most prominent of these are steel stud framing, insulated concrete walls, and structural insulated panels. All of these require the use of foam insulation to create successful energy efficient housing. A discussion is provided explaining insulated concrete form (ICF) systems and structural insulated panels (SIPs) and how the properties of EPS foam are suited to meet the unique requirements of these systems.

In addition ASTM Standard Specification for Rigid, Cellular Polystyrene (RCPS) Thermal Insulation (C 578) is discussed. It is the guide for polystyrene foam manufacturers and end users. It provides the specifications for the minimum performance which can be expected from various classifications of polystyrene foam. An understanding of these specifications can eliminate problems and confusion when using these materials. By following the specification, EPS materials can be ordered by type and specific application requirements.

Geosynthetics, products used below grade, including geomembranes, geotextiles and geogrids have been developed over the past twenty years. Now Geofoam EPS, a lightweight fill material, is available to assist civil engineers in stabilizing weak soil conditions in a variety of below grade applications. A brief history of the development and applications for Geofoam is provided.
Modeling and Experimental Evaluation of the Thermal Insulation Properties of Mineral Wool Products at High Temperature
Authors: de Dianous P , Pincemin F , Boulet P , Jeandel G
Published: March 2009

We have studied radiative transfer through insulating materials made of fibres and slugs (modeled respectively as infinite cylinders and spheres) at elevated temperatures. The same theoretical analysis is used for both fibers and spheres: Kerker-Mie theory is applied to determine the radiative coefficients of each type of particle, from the bulk glass complex refractive index and the fiber and slug diameter spectrum. Average radiative coefficients are determined for both fibers and slugs. The independent scattering hypothesis enables us to derive the total radiative coefficients of the whole material using a mass weighted average.

The radiative transfer equation is solved for a one-dimensional problem, using the multiflux approximation. The conductive part is determined using a semi-empirical formula. The coupling between conduction and radiation is accounted for.

This radiative model is applied to mineral wool products at room and elevated temperatures (400°C). Materials made of glass or rock fibers are considered. Special attention is given to fibrous materials with slugs.

We show that radiative heat transfer reaches a minimum for given fiber and slug diameters. We study the respective contribution of fibers and slugs to radiative transfer as a function of the mean diameter and the amount of slugs present in the fibrous material.

Calculated fluxes are compared to experimental ones measured on industrial rock and glass wool products for temperatures ranging from 24 to 400°C. The calculations are performed using the diameter spectra of fibers and slugs measured for these products. The influence of fiber orientation is also studied to better fit experimental data.
A Model for the Settling of Attic Loose-Fill Insulations
Authors: Svennerstedt B
Published: March 2009

An analytical model for settling of attic loose-fill thermal insulation can be helpful for both interpretation and prediction of observed settling behaviour. The prediction of the settling process in a model is also valuable, when estimating the thermal conductivity and thermal resistance of the loose-fill insulation after a certain life time.

This paper presents a mathematical model for settling of attic loose-fill thermal insulation, which has been developed from a four element model representing three settling factors. These factors are insulation density, climate of the attic and vibrations of the building structure. One element represents moisture change of the attic loose-fill insulation material and another element represents vibrations of the building structure.

Settling data from ten years of field observations were used to obtain coefficients needed by the model. The resulting equations were used to predict the amount of settling for cellulose fibre and mineral fibre insulations for a 30 year perod.
Development of Vacuum Super Insulations with Glass Cover and Powder Filling
Authors: Caps R , Rettelbach Th , Ehrmanntraut M , Korder S , Fricke J
Published: March 2009

An evacuated thermal insulation panel has been developed consisting of glass panes as covers and a powder filling. Several powder materials and mixtures of powders have been tested regarding their thermal conductivity and the critical gas pressure for the onset of gas conductivity. With an opacified precipitated silica powder a thermal conductivity of less than 0.003 W/mK could be reached if evacuated below 0.1 mbar. A value of 0.004 W/mK has been measured at an internal gas pressure of 1 mbar. A crucial point of panel design is the rim seal which should provide a negligible gas permeation and a small thermal heat transfer coefficient. With very thin stainless steel foils these requirements could be met.
Thermal Design of a Miniature Guarded Hot Plate Apparatus
Authors: Flynn DR , Gorthala R
Published: March 2009

Under contract from the National Institute of Standards and Technology, we have developed a prototype design for a miniature guarded hot plate apparatus that can be used to determine the thermal resistance of very small specimens (1 to 3 cm square) of thermal insulation materials at temperatures from -40 °C to +100 °C, with the capability to carry out measurements in air, selected gases, or vacuum. The overall design approach for this apparatus has been published previously. In the present paper, we provide details concerning the thermal design of the apparatus, including discussions of heater designs to promote temperature uniformity of the hot plate, guard designs to control extraneous heat gains and losses, material selection for the components of the apparatus, and techniques for temperature measurements.
Early-Time Estimation of the Thermal Resistance of Flat Specimens — Theoretical Analysis for Pure Conduction in a Homogeneous Material
Authors: Flynn DR , Gorthala R
Published: March 2009

An examination is made of the validity of estimating steady-state thermal resistance from apparent thermal resistance values obtained from measurements under transient conditions for homogeneous specimens in which heat transfer is entirely by conduction. It is shown that averaging the heat fluxes at the two surfaces of a specimen accelerates convergence to steady-state resistance values if the specimen is initially isothermal at a temperature which differs from its final mean temperature but no improvement is achieved if the specimen mean temperature does not change during testing. It also is shown that the analysis in this paper can be used to predict the thermal resistance from test data taken at early times. The findings presented in this paper must be used with caution since these preliminary analyses do not take into account the effects of radiation through the specimen, the temperature dependence of the thermal properties of the specimen, or the finite thermal resistance and heat capacity of the heat flow meters.
Field Experience and Dew Point Studies of a Retrofitted Roof
Authors: Carlson AR
Published: March 2009

A symposium on insulating materials would not be complete without discussing the effect of the thermal and vapor performance on potential condensation problems in insulated assemblies. Retrofitting the top of an existing insulated roof with an impermeable rigid or foamed insulation can lead to serious condensation-related maintenance problems. Dew point studies in Alaska indicate that the thermal resistance of retrofitted assemblies should be at least two times greater than the existing insulated wall, or roof to avoid condensation in the cavity, depending on local heating degree days [1]. Further, an exterior impervious insulated wall or roof assembly should be provided with some type of natural venting to relieve vapor pressure and allow excess condensate to drain and evaporate. Unfortunately, most condensation problems do not become apparent for 5 to 10 years, long after the one year warranty is null and void.

A computer spreadsheet will be presented that simulates dew point conditions in an insulated roof assembly to determine the proper selection and placement of the vapor retarder, insulation, and ventilation of the exterior skin to prevent further deterioration of the roof. This necessitated the computation and tabulation of surface temperatures, dew point temperatures, vapor pressures and relative humidities at various structural components of the insulated assemblies, particularly near the outer skin.
A Logical Extension of the ASTM Standard E96 to Determine the Dependence of Water Vapour Transmission on Relative Humidity
Authors: Lackey JC , Marchand RG , Kumaran MK
Published: March 2009

It is well known that the water vapour transmission properties of hygroscopic building materials depend on the local relative humidities(rh). Traditionally, the ASTM Standard E96 specifies only two conditions of rh. The dry cup method in the standard corresponds to a mean rh of 25 % and the wet cup to 75 %. This information is not enough to describe the behaviour of the material through the entire range of rh. European standards have already proposed an extension of the existing standard to address this issue. ASTM standard should follow this change. A logical extension of the E96 standard to include the effect of rh on water vapour transmission properties has been proposed and is being discussed by one of the C16 Committee Task Groups.

This paper presents the application of the proposed extension to several common building materials. The details include the operating principles of a constant temperature-rh chamber and the effects on the test results, of the vapour resistance offered by still air inside the cup, the surface resistances and buoyancy. The experimental data were used to critically assess the above effects. The data as well as the analyses of the data are expected to provide guidance to refine the existing ASTM Standard.
Preventing Environmentally-Caused Corrosion of Insulated Copper Lines
Authors: Hough PA , Lenox RS
Published: March 2009

Copper tubing systems are commonly used in plumbing, heating, cooling and refrigeration systems. Insulation is frequently applied to prevent surface condensation and energy loss or gain of these systems. Environmental factors can be responsible for the corrosion of copper tubing systems causing normally-dependable systems to fail. Urine, construction debris, inappropriate leak testing agents, road salt chemicals, leaking fittings, and even common surfactants can be causes of corrosion. Trapped water can make these corrodants much worse. Identification and elimination of these corrosion sources can result in a long-lived and dependable insulated copper tubing system.
Evaluating High-Temperature Intumescent Insulation Materials Under Fire and Blast Conditions
Authors: Parker AJ
Published: March 2009

This paper describes recent testing conducted to evaluate the performance of high-temperature intumescent materials under adverse fire and blast conditions. Results from fire performance evaluations currently protecting offshore oil platforms are presented. Extensive fire and blast qualification testing of epoxy-based intumescent materials has been conducted utilizing specially designed blast chambers, jet fire facilities, and laboratory furnaces. Blast chambers are capable of loading up to a 3 × 3-m insulated bulkhead assembly to a 2 bar over pressure and having a duration of approximately 250 millisecond generated by a controlled flammable vapor cloud explosion. The jet fire test exposes an insulated test specimen to a fire environment characterized by temperatures of approximately 1100°C, sonic gas velocities, and peak heat flux levels in excess of 300 kW/m2.
Measuring and Calculating the Thermal and Hygric Properties of Insulating Building Materials Over Wide Temperature and Moisture Ranges
Authors: Černý R , Toman J
Published: March 2009

Experimental and mathematical techniques for determining the thermal and hygric properties of insulating building materials in the temperature range of 0°C to 1000°C and moisture range from zero moisture content to the maximum water saturation are analyzed in the paper. Nona diabatic methods are preferred in measuring the specific heat. The methods based on the analysis of measured temperature and moisture fields are recommended for determining thermal conductivity, thermal diffusivity and moisture diffusivity. In measuring water vapor diffusion, transient methods are preferred. Thermal and moisture expansion are treated using the superposition principle. The application of the proposed methods is illustrated by experiments with two typical insulating building materials, the significance of temperature and moisture influences for the mentioned thermal and hygric parameters is demonstrated.
Consideration of Safety Factors in the Life Extension Modelling of Components Operating at High Temperatures
Authors: Nikbin KM
Published: March 2009

The appraisal of high temperature structural integrity and design and life extension of engineering components, using fracture mechanics methodologies, is dependent on available material properties derived from short term tests. The scatter attributed to fabrication, geometry, testing, material creep properties could vary by up-to a factor of ±2.5. The parameter C* adopted in ‘The standard test method for measurement of creep crack growth rates in metals’ (ASTM STP E1457-92) and also in the R5 [1–2] and A16 [3–4] crack growth assessment procedures, can vary by a further factor of ±3.3 using differing experimental methods for its estimation. The NSW [5–6] model which describes cracking behaviour over the plane stress/strain range identifies this variability in terms of crack tip constraint. It is concluded from the NSW model (Nikbin. Smith and Webster [5,6]) that for creep ductile materials a factor of 25 in crack growth rates would bound the creep cracking data and an additional factor of up-to 10 would be added when transient and initiation behaviour prior steady crack growth were to be included in the life predictions.
Improved Fatigue Resistance of 7050 Thick Plate Aluminum Through Minimization of Microporosity
Authors: Deschapelles JB , Rice RC
Published: March 2009

This paper illustrates the substantial fatigue life improvements that have been achieved with 7050 heavy gauge plate over the past two decades. The load control fatigue resistance of 7050-T7451 thick plate is shown to decrease with increasing plate thickness at both the plate quarter-thickness (T/4) and mid-thickness (T/2). These reductions in fatigue resistance are shown to be most substantial at the plate mid-thickness, and they are shown to be directly related to the maximum size of remaining micropores.
Low-Cycle Fatigue Testing of Tubular Material Using Non-Standard Specimens
Authors: Tipton SM
Published: March 2009

Coiled tubing life prediction models are based on the use of standard low-cycle fatigue data. However, coiled tubing dimensions and the ultra-low-cycle life regime of interest, combine to complicate “standard” experimental methodology. This paper describes coupon design and testing procedures that alleviate the difficulties inherent to strain-controlled low-cycle fatigue testing of tubular material. Data sets are presented and compared to existing sets generated using smaller specimens. It is shown that the refined approach facilitates the generation of data in the ultra-low-cycle coiled tubing operating regime. The difference between the morphologies of the outer and inner surfaces of the specimens, as manufactured by standard tube rolling techniques, proved to be influential, but could not fully explain the comprehensive tendency for cracks to initiate at the inner surface. The inherently lower fatigue resistance of the inner surface indicates the theoretical existence of a “threshold defect severity” which must be exceeded on the outer surface before it would affect the fatigue life of the tubing.
Failure Analysis of an Age Hardenable, Nickel Base Superalloy Barrel Nut from an Army Attack Helicopter
Authors: Champagne VK
Published: March 2009

During a routine preflight inspection at Ft. Hood, an outboard barrel nut was found to be cracked on an Army helicopter. The part was fabricated from Inconel 718 (UNS N07718) according to AMS 5662F, “Alloy Bars, Forgings, and Rings, Corrosion and Heat Resistant”. Subsequent inspections at Ft. Hood and Ft. Rucker revealed an additional seven barrel nuts with large cracks. The components are used in many critical applications. The failures under investigation in this study were relegated to the vertical stabilizer of the aircraft. The failures were all attributed to hydrogen induced cracking. Galling between the unlubricated bolt and the nut threads provided the sustained hoop stress while galvanic corrosion of the carbon steel retaining clip in contact with the barrel nut generated hydrogen. Microstructural analysis of the nut revealed excessive banding consisting of a Widmanstatten phase and MC carbides which ran parallel to the fracture plane. The grains were almost completely surrounded by an undesirable acicular delta phase. No evidence of Laves phase was observed. Recommendations were made to utilize a corrosion inhibitive lubricant on the threads of the barrel nut and mating bolt to reduce galling and the consequential high stresses which result from metal to metal contact during torquing. A stress analysis of the part showed that the high strength level of the material could be reduced to increase fracture toughness and resistance to hydrogen cracking. The acicular delta phase should be avoided in accordance with AMS 5662F and the extrusion direction of the material should be parallel to the principal loading direction. Salt fog testing of the proposed barrel nut configuration revealed that the shoulder height base thickness should be increased. Future vendors should qualify their product by conducting a prescribed salt fog test incorporating the prescribed torque requirements. Finally, the material used to fabricate the retaining clip should be changed to prevent galvanic corrosion.
Effects of Wear-Resistant Coatings on the Fatigue Strength of 4340 Steel
Authors: Duffy ER
Published: March 2009

For applications using 4340 steel where hardened surfaces are required in a marine environment, surface coatings are necessary. Coatings that resist corrosion and provide wear resistance generally degrade the fatigue performance of the substrate metal. Shot peening before plating was ineffective in preventing a loss of fatigue life of plated steel bars compared to bare steel test bars which were not shot peened. The maximum residual compressive strength produced by shot peening was measured and was less than the maximum applied tensile stress in fatigue. As-plated electroless nickel has poor sliding wear resistance compared to either electroplated nickel or chromium in sliding wear at a contact stress of 37 Mpa. The tensile strength decreased in proportion to the volume fraction of coating applied to the steel substrate.
Fracture Mechanics Analysis of Cast Duplex Stainless Steel Elbows Containing a Surface Crack
Authors: Le Delliou PA , Sémété P , Ignaccolo S
Published: March 2009

Some components of the primary loop of a PWR are made of cast duplex stainless steel. This kind of steel may age even at relatively low temperatures, (below 400‡C, which is within the temperature range of PWR service conditions), leading to a significant decrease of its toughness. This is why a large research program was initiated on the fracture behaviour of aged duplex stainless steel elbows in France. The main task of this program was to test three 2/3-scale models of aged PWR primary loop elbows. The first two tests (called SEM1 and SEM2) were conducted under in-plane closure bending at 320‡C; the third (called SEM3) was conducted under constant internal pressure and inplane closure bending at 60‡C. The first two elbows contained a semi-elliptical notch machined into the outer surface of one flank, oriented either longitudinally (SEM1 test) or circumferentially (SEM2 test); the third elbow contained both notches described above, one on each flank. This paper presents the results of the experiments, the finite element calculations and the ductile fracture mechanics analyses that were performed.
A Comparison of Knowledge and Behavior in Young Injured and Non-Injured Skiers
Authors: Macnab AJ , Cadman RE , Greenlaw JV
Published: March 2009

The Skier Knowledge Questionnaire (a survey of knowledge and behavior) was given to 863 non-injured and 118 injured skiers and snowboarders aged 5 to 17 years at Blackcomb Mountain in British Columbia during 1993–94 to help identify relevant factors in injury prevention initiatives.

The injured cohort had less knowledge of the Skiers Responsibility Code. In both groups, almost half had had no lessons, 31% had had bindings adjusted by non-professionals and chair lift safety bars were used one ride in four by children 13 to 17 years. They wore helmets slightly less often. Both groups skied regularly through the trees, and 20% had skied on closed runs. Excessive speed was identified as the major cause of injury. Jumping was not recognized to contribute to injury.

The lack of knowledge of safety rules and skiing without due care in young adults indicate that some major ski and snowboarding injuries are preventable.
Vision—An Essential Factor for Safety in Skiing: Perception, Reaction, and Motion Control Aspects
Authors: Senner V , Jendrusch G , Schaff P , Heck H
Published: March 2009

Observation and perception errors in combination with lack of attention explain the majority of all falls in skiing. This associates vision and vision deficiencies with safety aspects in skiing. The purpose of this study was to determine the effect of reduced visual acuity on the reaction time of a skier in safety-critical skiing situations.

For this purpose, field experiments were conducted in the 1995/96 winter season. The subjects had to pass over a prepared ledge in the terrain and react to simulated obstacles, which were partly blocking the course. All experiments were video recorded; in total more than 220 trials were conducted. We tested three different types of obstacles: ice patches, a standing skier, and a skier just starting to move. Two experimental conditions were examined, normal visual acuity and a reduced visual acuity. The acuity reduction to 20% of normal was achieved by the use of special goggles. From the videotape, the subjects' time for an evasive action was determined and statistically analyzed.

No significant change of the reaction time with reduced visual acuity could be seen for the bigger obstacles i.e., the standing skier and the moving skier. However, with the simulated ice patches, the increase of the reaction time was significant (p = 0.01) with an average increase of 35%. From the obtained results it is concluded that skiers not wearing their corrective lenses may feel safer than they really are. They can perceive larger, stationary, or moving objects, however they might not be aware of the risk from low-contrast obstacles.
Customs and Practices at U.S. Ski Areas for Mitigating Common Hazards through Trail Configuration and Maintenance
Authors: Penniman D
Published: March 2009

U.S. ski areas have improved trail systems by following various configuration and maintenance customs and practices. Some of these customs and practices address specific safety issues such as slope gradients and widths, trail intersections, beginner areas, side-hills, abrupt turns, separating divergent ability skiers, surface grooming, and the presence of snow-making machinery and other man-made structures on ski trails. This paper describes these safety issues and categorizes U.S. ski area configuration and maintenance customs and practices that address them according to a known “safety hierarchy.”
Analysis of Ankle Deflection During a Forward Fall in Snowboarding
Authors: Hull ML , Estes M , Wang E
Published: March 2009

Towards the general goal of preventing ankle injuries in snowboarding accidents, the objective of this project is to develop a dynamic system model of a snowboarder and assess which model parameters, particularly those attributed to the boot, most strongly influence ankle deflections during a forward fall. To satisfy this objective, a system model was created that included the rider, the boots, the snowboard, and the snow as components. Through dynamic simulations, peak ankle deflections were computed over realistic ranges of input parameter values for each of the model components. Defining sensitivity as the total change in peak ankle deflection over the range of a particular parameter studied, results indicated that the peak ankle deflection was most sensitive to the boot stiffness. Although lower, the sensitivity of the peak ankle deflection to the snow model parameters was still significant, being roughly half of the boot sensitivity. Increases in both snow stiffness and snow damping both caused higher ankle deflections. Variations in both snowboard stiffness and anthropometric parameters had little effect. Due to the strong dependence of ankle deflection on boot stiffness, the potential exists for mitigating the ankle injury problem through judicious design of the boot.
Strain of the Anterior Cruciate Ligament Increases Linearly with Quadriceps Contraction
Authors: Bach JM , Hull ML
Published: March 2009

This work was designed to answer two important questions concerning injury mechanics of the anterior cruciate ligament (ACL). One question was whether strain of the ACL increased linearly with increasing quadriceps contraction, and the other was whether strains in the anteromedial (AMB) and posterolateral (PLB) bundles were different at any point in the flexion arch.

To answer these questions experiments were performed to determine the relationship between increasing quadriceps force and strains in both the AMB and PLB. Five unembalmed knee specimens were instrumented on both bundles of the ACL using liquid mercury strain gages. Quadriceps loads of 0, 250, 500, 750, and 1000 N were applied at flexion angles of 0, 15, 30, 60, 90, and 120°. Data were analyzed using repeated measures analysis of variance, as well as linear and quadratic regressions. The results indicated that there were no significant differences in strains between the two bundles and that the relationship between quadriceps load and ACL strain was highly linear for flexion angles of 60° and less, where the quadriceps caused markedly increased strains above those developed during passive motion.
Comparison of Needed and Recommended Retention Settings for Snow Skiing
Authors: Scher IS , Mote CD
Published: March 2009

The current ASTM ski binding setting standard, Practice for Selection of Release Torque Values for Alpine Ski Bindings (F 939-93), was evaluated by comparing the forces measured during alpine skiing to the ASTM recommended release forces. For a twelve subject sample, the forces and moments at the toe and heel ski release bindings were collected during skiing, walking, and executing stationary turns. The subjects included all skiing levels from beginner to professional racers and varied widely in weight and age. For each subject, the maximum lateral force at the toe and vertical force at the heel was measured during runs where falls and releases of the binding did not occur.

The ASTM recommended release settings were significantly higher than the forces required to ski normally for ten of the twelve skiers. For nine of the subjects, the vertical force at the heel required to ski (retention setting) was less than 45% of the vertical release force permitted by the standards; these subjects could have reduced their release setting at the heel by 55% (between 425 and 711 N) without causing inadvertent releases of the binding during the skiing maneuvers. Similarly, ten of the subjects skied within 67% of the current settings and could have lowered the lateral release setting at the toe by 33% (from 61 to 111 N) without signaling for inadvertent release; for inexperienced, lightweight skiers, the release setting at the toe could have been lowered by 38%.

A method for determining the minimum retention forces required to ski in these tests for any and all force components at the toe and heel binding is presented. These minimum retentions do not correlate well (r < 0.7) to subject to age, height, or weight. Furthermore, weight was found to be a poor predictor of the maximum lateral force at the toe and vertical force at the heel. Accordingly, setting standards cannot rely primarily on these variables for prediction of minimum retention.
Signal Detection Theory: A Model for Evaluating Release/Retention Criteria in Alpine Ski-Binding-Boot Systems
Authors: Shealy JE , Ettlinger CF , Johnson RJ
Published: March 2009

Between 1972 and 1997 the authors prospectively evaluated injuries reported to the injury clinics at the base lodges of the Sugarbush ski area in northern Vermont. During that time, the number and rate of injuries resulting from self-reported inadvertent releases and failure-to-release incidents resulting in mid-shaft tibial fractures have been tracked. Rates of these two injury modes, in absolute terms mean days between injuries (MDBI) and in relative terms as a percent of all injuries have declined by more than 85 and 75%, respectively. The performance of the ski-binding-boot (SBB) systems have been analyzed in the context of signal detection theory. The simultaneous improvement in system performance in terms of lower injury rates due to both inadvertent release and failure-to-release modes is most likely the result of a variety of intervention measures, such as standardization of ski boot sole configurations, shop practices that require testing before release of the SBB system to the customer, better binding system hardware design that has reduced and controlled friction between the boot and other parts of the system, and empirical research into the dynamic performance of binding systems, the biomechanical strength of the tibia, and the minimum SBB retention requirements.
A Release Binding for Snowboards
Authors: Bally A , Shneegans F
Published: March 2009

Release bindings could help prevent some of the lower extremity injuries in snowboarding. A few brands already exist on the market, however with very limited success. From the technical point of view, further improvements of such bindings require an evaluation of the minimal retention levels independently in each release direction. In order to allow such an evaluation, an experimental release binding with independent adjustments was developed and tested in the field. Tests were carried out in various snow and slope conditions, with participation by riders of very different levels. The minimal retention levels were measured for each rider at the end of the tests. The use of such a binding, with appropriate adjustment proved to be possible without necessarily increasing, in an unacceptable way, the risk due to inadvertent releases.
Risk Factors in Skiing and Snowboarding in Austria
Authors: Boldrino C , Furian G
Published: March 2009

In the winter season 1995/96 approximately 8 million skiers and snowboarders took part in these sports on Austrian slopes (7.4 million skiers, 0.7 million snowboarders) [1]. Two-thirds of these were visitors from abroad. In the same period, some 70 000 skiers and 8000 snowboarders were injured so seriously that they required medical treatment [2]. The purpose of this study is to evaluate and analyze risk factors involved in skiing and snowboarding and to derive preventative measures. Between January and March 1997, 160 injured skiers and 102 injured snowboarders were interviewed in four Austrian hospitals. As control groups, 750 skiers and 750 snowboarders were questioned directly on the slopes in four ski areas. A comparison between the injured and the noninjured groups enabled relevant risk factors to be identified. This study shows that skiers and snowboarders have different risk factors. These differences should be considered when developing preventive measures.
Microstructural Features of Implant Quality 316L Stainless Steel
Authors: Disegi JA , Zardiackas LD
Published: March 2009

ASTM F 55 material specification was issued in 1965 to cover the metallurgical requirements of Type 316/316L stainless steel bar and wire for the manufacture of surgical implants. Eventually, it was recognized that austenitic implant stainless compositions with well defined nonmetallic inclusion limits would be desirable. The low carbon 316L alloy with specified inclusion limits emerged as the most widely used implant quality stainless material over the last 30 years. Microstructural requirements include a fully austenitic microstructure that is free of delta ferrite when examined at 100X magnification and an ASTM grain size of five or finer. The importance of low sulfur content, effect of secondary phases, intergranular corrosion resistance, and the compositional requirement %Cr + 3.3 × %Mo ⩾ 26 are highlighted. Various clinical factors are discussed relative to the microstructural features of implant quality 316L.