bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of a Knee Injury Protective Brace for Ice Hockey Players
Authors: Tegner Y , Odelgard B , Johnson G
Published: December 2008

In Sweden, many ice hockey players use so-called derotation braces in order to prevent knee injuries. Unfortunately, these braces are expensive, and reports have claimed that serious knee injuries can occur in spite of the use of these braces.

In this study, it was found that 24% of the players in the two highest leagues use these preventive braces in order to reduce the risk of knee injury. The different braces were tested regarding their effectiveness in reducing rotation and abduction/adduction in the knee joint; it was shown that these braces reduced these movements in the knee. The braces were also investigated to determine if they impaired performance and strength. It was found that the design of the brace was of importance, as some braces effected strength and performance negatively.

The ability of the braces to withstand external torques was also investigated. Here the design of the braces was of importance in terms of the ability to take up external applied forces. Braces with metal bars and a three- or four-point fixation system seemed to be super rior, but the load that the brace can resist appeared to be too low to prevent a knee injury.

The authors conclude that, if a brace is to prevent injury, it should probably have a new design.
The Dynamic Role Played by the Ice Hockey Stick
Authors: Hoerner EF
Published: December 2008

A description is given of the ice hockey stick as a piece of equipment. The mechanics of its functions are described, and its role in ice hockey safety is discussed.
Natural Ice Facilities
Authors: Mittelstaedt AH
Published: December 2008

The use of natural and seminatural facilities for ice skating and ice hockey has increased because of many problems with artificial rinks, including energy, construction, insurance, and lack of financing. With the use of natural and seminatural facilities, there have been injuries and deaths resulting from improperly constructed facilities. This paper outlines the critical points that must be addressed in designating natural and seminatural facilities for ice hockey, ice skating, and other sports requiring ice as a playing surface.
Impact of Full Face and Visor Type Hockey Face Guards
Authors: Smith TA , Bishop PJ
Published: December 2008

Full facial and visor-type face protectors were struck over the nose and eye region of a headform by a hockey puck shot at speeds of 27 to 45 m/s (60 to 100 mph). Deformation characteristics of wire face masks, polycarbonate face masks, and polycarbonate visors (eye protector) were studied using high-speed film.

The test results demonstrated that the full facial protectors (both wire and polycarbonate) did not permit any contact with the face until puck velocities exceeded 33.5 m/s (74 mph). In comparison, facial contact with the visor occurred during all visor impacts.

The results indicated that the visor-type shields do not provide complete protection in ice hockey. While the visor may prevent the loss of an eye, wearing it in place of full facial protection will not reduce the potential for serious facial lacerations or oral injuries. The data indicate conclusively that full face shields still offer the best protection against impacts which commonly occur in ice hockey.
Development of an Impact Testing Method for Protective Helmets
Authors: Johnson GI
Published: December 2008

A set of standard methods for testing protective helmets on the Swedish market was established by the Swedish Ice Hockey Association in the early 1960s. These standards included impact tests conducted by dropping a weight onto the helmet attached to a fixed dummy head.

Since there had been criticism of this method, an investigation was started in 1974 by the National Swedish Board for Consumer Policies to evaluate various alternatives for the impact testing of protective helmets.

Starting with a literature survey of different methods in use, the investigation continued with a study of computer simulation models of a selected number of impact testing methods. Largely based on the results of the computer simulation study, a final selection of impact method was made. In order to verify the theoretical results, a large program of impact testing on different types of helmets was conducted using the selected testing method.

After slight modifications, this impact test and corresponding equipment was adopted by the Swedish National Testing Institute as part of their testing standard for protective helmets.
The ASTM F 1045-87 Standard Performance Specification for Ice Hockey Helmets
Authors: Morehouse CA
Published: December 2008

In this article, the apparatus and procedures for conducting the impact and chin strap tests required in the ASTM Standard Performance Specification for Ice Hockey Helmets (F 1045-87) are described briefly. An attempt was made to describe these tests in a manner that can be understood by individuals with no special scientific background. In addition to the descriptions of the apparatus and procedures, the advantages and disadvantages of the principal components of the tests are included. These have provided much of the rationale for the development of the standard in its current form.
Residual Problems and the Scrap Industry
Authors: Pflaum DA
Published: December 2008

Purchased scrap is generally accepted as a major source of residual and unspecified elements in steel. Current trends in the steel industry will precipitate a more important role for scrap as a raw material. A principal factor in minimizing residual elements is the monitoring and control of this nonhomogeneous, nonmanufactured product by scrap processors and steel producers. By examining the variation in scrap grades through computer analysis and by integrating various techniques such as material segregation, inspection, and statistical process control procedures, more predictable and potentially lower residual levels can be achieved.
Some Practical and Economic Aspects of Residual Element Control in Engineered Bar Products
Authors: Glasgal BM
Published: December 2008

With the increasing use of electric arc furnaces (EAF) for the production of carbon and alloy special quality engineering bar steels, controlling and restricting residual elements have become an increasingly significant economic component of steelmaking. This paper reviews the trend in EAF production and discusses the various types of scrap used in EAF steelmaking and the formulation of scrap charges to achieve residual control. Reasons for specifying residual restrictions and some rational alternatives are presented.
Production of Super Clean Steels—Deoxidation Mechanism During Ladle Refining
Authors: Meyer W , Kucharz A , Hochörtler G
Published: December 2008

Investigations carried out by several institutions under Projects RP559, RP2060, RP1403, RP2741 for the Electric Power Research Institute, Palo Alto, CA, resulted in a 3.5% NiCrMoV steel completely free from temper embrittlement as a material for low pressure rotors but also for combination proberty rotors, for example, integral high-pressure low-pressure (HILP) rotors for future steam plants. This steel contains very low percentages of residual elements including sulfur and phosphorus, and its contents of aluminum, silicon, and manganese are also very low.

The main problem in producing such a steel on an industrial scale is gaining a sufficiently low oxygen content as a precondition for successful desulfurization and high cleanliness. This situation is only possible by applying ladle refining techniques. Two model rotors of this “super clean steel” were produced and tested. The tests proved complete resistance to temper embrittlement.

As an approach for further process development and for the economic production of “super clean steels,” the mechanism governing the deoxidation was investigated in detail by means of trial heats. The influences of the composition of process slags and the influence of the ladle linings were examined. The deoxidation was found mainly to be based on steel-slag reactions. The minimum oxygen content achievable in the steel is limited by interactions between ladle linings and melt, which create a dissociation of the linings and an oxygen supply to the liquid steel.
Effect of Total Residual Content (Cu+Cr+Ni) on the Machinability of AISI 1215 Steel
Authors: Yaguchi H , Bhattacharya D , Yanase M
Published: December 2008

The effect of total residual content (Cu+Cr+Ni) on the machinability of American Iron and Steel Institute (AISI) 1215 (UNS G12150) low carbon resulfurized free-machining steel was investigated jointly between Inland Steel Company in the United States and Nippon Steel Corporation in Japan. Three different machinability tests were used. At Inland, the automatic screw machine test using a modified version of the test method outlined in ASTM Method for Evaluating Machining Performance of Ferrous Metals Using an Automatic Screw/Bar Machine (E 618-81) was used. At Nippon, the automatic screw machine test with its own methodology and the cyclic plunge test were used. Three levels of total residual contents were obtained through addition of copper, chromium, and nickel in ingots. The amounts of these three elements were changed simultaneously to simulate practical conditions. The total residual contents obtained were 0.07, 0.20, and 0.28 wt%. The automatic screw machine test at Inland revealed that rough form tool life, based on part growth, deteriorates slightly when residual content is high. Poor surface finish is occasionally observed in medium and high residual content heats in the automatic screw machine tests carried out both at Inland and Nippon. On the other hand, no deterioration of surface finish was observed in the cyclic plunge test. Overall, the authors conclude the machinability of AISI 1215 steel deteriorates slightly when the total residual content becomes very high; however, it is not affected significantly within the range of normal total residual contents observed in these steels made in the BOF, that is, 0.05 to 0.12%.
The Effect of Boron, Copper, and Molybdenum Residuals on the Corrosion Resistance of Type 304 Stainless Steel
Authors: Kearns JR , Johnson MJ , Aggen G , Edsall WD
Published: December 2008

Systematic variations in the chromium, nickel, copper, molybdenum, and boron and B contents of American Iron and Steel Institute (AISI) Type 304 stainless steel (UNS S30400) were evaluated by electrochemical and immersion corrosion tests in oxidizing, reducing, and chloride solutions. In one series of tests, the chromium and nickel alloy contents were maintained within the flat rolled product tolerance range (17.8 to 18.0 wt% chromium, 7.8 to 8.0 wt% nickel) while the copper and molybdenum alloy contents were increased from a residual level (< 0.5 wt%) to a range from 0.6 to 0.7 wt%. Strip specimens with such compositions performed as well as others that had chromium and nickel contents within the specified analytical limits for tubular products (18.0–20.0 wt% chromium; 8.0–11.0 wt% nickel) and copper and molybdenum contents below 0.5 wt%. The results of an ASTM A01.17 committee interlaboratory program (twelve industrial labs testing per ASTM Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels (A 262-85a), Practice C, did not reveal any significant difference in the intergranular corrosion resistance of the said compositions. None of the compositional modifications resulted in increased susceptibility to sensitization as caused by welding or heat treating.

The effect of residual boron on the carbide precipitation kinetics and intergranular corrosion resistance of mill and laboratory produced Type 304 stainless was also evaluated. The corrosion rates for fully annealed samples in boiling nitric, phosphoric, acetic, oxalic, and lactic acids were not related to alloy boron contents in the range 0.0003 to 0.0056 wt%. The rate of corrosion for sensitized (815°C for 24 h) samples in boiling 65 wt% nitric acid declined rapidly with increasing boron contents in the range from 0.0004 to 0.0011 wt%. The corrosion rates for sensitized samples containing 0.0011 to 0.0056 wt% boron were constant and, on average, 0.6 mm/y (0.002 ipm) higher than those for samples in a fully annealed condition.
Influence of Low and Ultra Low Sulfur Contents on Weldability of Ferritic Steels
Authors: Bourges P , Blondeau R , Cadiou L
Published: December 2008

The existing possibilities of steelmaking imply that ultra low sulfur contents can be obtained. The weldability of these steels had not yet been clearly defined as good or not. In this study the welding behavior has been determined both for normalized steels, and quenched and tempered steels. Results concern underbead hardness in the heat affected zone (HAZ) and critical preheat temperature determined by the implant test. Ultra low sulfur steels appear to present a significant improvement in weldability. The underbead hardness is not affected by a sulfur content decrease. The preheat temperature is the same for different stress directions (that is, longitudinal and short transverse) only for steels with a sulfur content lower than about 15/20 ppm. The influence of the weld metal's hydrogen content on cold cracking prevention is reduced with ultra low sulfur steels.
Embrittlement of a Copper Containing Weld Metal
Authors: Christoffel RJ , Silvia AJ
Published: December 2008

Elevated temperature isothermal exposure of a “weathering” steel weld containing approximately 0.5% copper, in the as-welded condition, embrittled the weld as characterized by an increase in strength and a decrease in toughness and tensile ductility. A similar embrittlement was not encountered for material exposed in the postweld stress relieved condition. The embrittlement was attributed to the precipitation of an iron-copper intermetallic compound. Control of copper content below the solubility limit or the use of a postweld stress relief heat treatment should prevent the occurrence of any significant embrittlement.
A Newly Developed Ti-Oxide Bearing Steel Having High HAZ Toughness
Authors: Yamamoto K , Matsuda S , Haze T , Chijiiwa R , Mimura H
Published: December 2008

A study was carried out on the transformation characteristic of a newly developed Ti-O steel in comparison with that of ordinary steels. The microstructure of the weld heat affected zone (HAZ) in the Ti-O steel is characterized by the formation of intragranular ferrite plate (IFP), or so-called acicular ferrite, which was found to start from titanium sesquioxide (Ti2O3) particles dispersed in the matrix of the steel. The welding thermal cycle simulation test on the Ti-O steel showed that IFP development takes place over a wide range of conditions such as heating temperature and chemical composition. The high stability of Ti2O3 particles at high temperature explains the effect of the former condition. The effect of the latter can be well understood from the distribution of Ti2O3 particles, which is irrelevant to the microsegregation of alloying elements such as manganese and niobium. IFP formation restricts development of ferrite side plate, refines the effective grain size, and improves HAZ toughness. Various experimental results suggested that the Ti2O3 particle has an IFP formation function through the manganese sulfide (MnS) attached on it.
Process Modeling of Thermoplastic Matrix Composites
Authors: Leung C-L , Liao TT
Published: December 2008

Heat transfer is perhaps the most critical parameter in the processing of thermoplastic matrix composites. Temperature distribution affects the quality and microstructure of the final product in that flow, compaction, melting, and crystallization are thermally controlled processes. Using readily available thermal properties of the composites, a model that predicts the temperature profile within a composite laminate during processing was developed. Graphite-reinforced thermoplastic composites of various thicknesses, up to 80 plies, were fabricated and used to validate the analytical thermal profiles. When compared with empirical measurements, the heat transfer model was shown to generate highly accurate temperature distributions within the composites under various processing conditions. When correlated with the dynamic viscosities of the polymer at various temperatures, t-T-V profiles of the composites during processing can then be obtained.
Thermoplastic Coating of Carbon Fibers
Authors: Edie DD , Gantt BW , Lickfield GC , Drews MJ , Ellison MS
Published: December 2008

A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread over a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol % fiber prepregs can be obtained.
Thermoplastic Matrix Composites: Finite-Element Analysis of Mode I and Mode II Failure Specimens
Authors: Bankert RJ , Lambropoulos ND , Shephard MS , Sternstein SS
Published: December 2008

A finite-element analysis was conducted to evaluate the stress distributions within Mode I and Mode II failure specimens, assuming both isotropic and orthotropic elastic material properties. The effects of anisotropy on both the magnitude and the location of the highest stress concentration at the vicinity of the crack tip are significant. The results from modeling realistic blunt crack tip geometry and resin-rich zones imply that local variations in the microstructure strongly influence the stress state near the crack tip and therefore the measured fracture properties. In addition, the features of a viscoelastic model for thermoplastic matrices are described. This model will be used in future investigations of matrix-dominated failure phenomena.
Effects of Moisture Content on the Mechanical Properties of Polyphenylene Sulfide Composite Materials
Authors: Hoa SV , Lin S , Chen JR
Published: December 2008

Effects of moisture absorption on the mechanical behavior of glass-reinforced polyphenylene sulfide (PPS) composites were examined. At 100°C and 95% relative humidity, significant moisture absorption into PPS composites took place within a period of one or two weeks. Large reduction in tensile strengths from 25 to 46% were observed. This reduction is significantly increased up to 60% if the thermoplastic material is not properly crystallized.
Moisture Effects on Mode I Interlaminar Fracture Toughness of a Graphite Fiber Thermoplastic Matrix Composite
Authors: Lucas JP , Odegard BC
Published: December 2008

Mode I interlaminar fracture toughness was determined for a high-temperature thermoplastic matrix, intermediate modulus graphite fiber composite laminate. Interlaminar fracture toughness and fracture energy were determined for a unidirectional layup, continuous-fiber reinforced thermoplastic composite by using a nonconventional specimen. A short bar hybrid test specimen (HTS) was developed and used in this investigation to determine the effect of moisture on mode I delamination fracture toughness and critical strain energy release rate. Exposure of the thermoplastic composite laminate in a water bath for over 400 h had an insignificant effect on delamination fracture toughness. Moreover, a fractographic examination did not reveal effects of absorbed moisture on fracture surface morphology and failure processes. Fracture was characterized primarily by matrix decohesion and fiber pullout. There was, however, clear evidence of fracture mechanisms that contributed significantly to mode I fracture energy of the composite. Crack bridging by isolated, single fibers and fiber bundles was prevalent, particularly after a considerable degree of crack extension in the laminate. Translaminar, secondary microcracking was observed in the vicinity of the primary crack tip.
The Effects of Testing Methodology on the Promoted Ignition-Combustion Behavior of Carbon Steel and 316L Stainless Steel in Oxygen Gas Mixtures
Authors: MC Ilroy KM , Zawierucha R
Published: December 2008

Energy release from a substance with relatively low oxygen compatibility is a situation which could result in the ignition and combustion of more oxygen-compatible materials such as the structural metals used in gaseous oxygen systems. At the present time there are no standard ASTM test methods for testing metals ignition and combustion in gaseous oxygen over the range of pressures and purities required for the broad range of oxygen applications which may be encountered.

Within recent years, there nas been an increase in the number of metals ignition-combustion studies which have been conducted at pressures in excess of 3.55 MPa. The studies have been conducted under both flowing and static conditions with different promoter systems. Some of the approaches might form the basis for standard ASTM test methods in metals ignition-combustion in gaseous oxygen. Discussion regarding the influence of various test variables which could affect selection of a standard test method does appear in the literature.

This paper discusses experimental results obtained with caroon steel and AISI 316L stainless steel using three different apparatus for characterizing metal-oxygen ignition-combustion tendencies. One test method used a 100 mm diameter static chamber with hydrocarbon and wire promoter. The second test method was similar but the chamber was 8 times larger in volume. In contrast to these approaches the third method was a dynamic or flow tester in which tne gas mixtures were continuously flowed past the test specimen. The oxygen purities of the gas mixtures varied from 40 to 99.998% oxygen. Test data and methods were compared.
Promoted Combustion of Nine Structural Metals in High-Pressure Gaseous Oxygen; A Comparison of Ranking Methods
Authors: Steinberg TA , Rucker MA , Beeson HD
Published: December 2008

Nine structural metals were evaluated for relative nonflammability, in a high pressure oxygen environment. The metals studied were: 316, 321, 440C and 17-4 PH stainless steels (SS), Inconel 600, Inconel 718, Waspaloy, Monel 400, and Aluminum 2219. A comparison is made between four methods which have been used to provide a relative flammability ranking of metals. A new relative ranking method is presented. Limitations of the ranking methods are assessed by investigating the effects of changes in test pressure, sample diameter, type of promoter, and sample configuration. Ranking methods which apply velocity as the primary ranking criterion are found to be limited by diameter effects. Methods which apply extinguishing pressure as the ranking criterion are found to be non-selective for metals with similar flammabilities. An overall ranking in agreement with all methods considered, for the metals described in this report, over a range of pressures and diameters, in order of combustion resistance, is: 1) Monel 400; 2) Inconel 600; 3) 316 SS, Waspaloy, Inconel 718, 17-4 PH SS, 440C SS, 321 SS; and 4) Aluminum 2219. Distinction is possible for metals in the third position; however, the relative ranking depends on the method chosen.
Further Studies of Factors that Affect the Spontaneous Ignition Temperatures of Non-metallic Materials in Gaseous Oxygen
Authors: Wharton RK , Nolan PF , Swindells I
Published: December 2008

We recently reported work done using the BS 3N 100 bomb test to investigate the effect of experimental parameters on the spontaneous ignition temperature (SIT) of three well documented materials. These studies have now been extended to encompass a wider range of materials and also to investigate the effect of contamination.

Results from a detailed investigation of the performance of Neoprene in the test indicated that the dependence of SIT on various testing parameters may be influenced by the high proportion of chlorine in the molecule.

By examining an extended range of polymeric materials in the test it has been possible to evaluate the acceptability criterion for oxygen service proposed by Lapin.

A range of experiments using PTFE with hydrocarbon grease contamination has yielded data that enable quantification of the reduction of SIT with mass of contaminant.
Ignition of PTFE-Lined Flexible Hoses by Rapid Pressurization with Oxygen
Authors: Janoff D , Bamford LJ , Newton BE , Bryan CJ
Published: December 2008

There has been increasing concern in recent years about the ignition sensitivity of polytetrafluoroethylene (PTFE) lined flexible hoses used in oxygen service. Stainless steel braided flexible hoses lined with PTFE were tested in a high-volume pneumatic-impact system. The objective of the testing was to characterize the ignition mechanism by determining the effects on ignition of impact pressure, pressurization rate, and volume upstream and downstream of the flexible hose. Ignitions occurred at impact pressures well below the working pressure of the hoses, and at pressurization rates that can easily be obtained with manually operated valves. The hoses ignited at the downstream end and combustion propagated back toward the source of fresh oxygen. The addition of stainless steel hardline downstream from the hose prevented ignitions at all pressures and pressurization rates. Internal observations revealed evidence of shock ionization of the oxygen prior to ignition. Although adiabatic compression of the oxygen is the most likely source of thermal energy for ignition, shock ionization of the oxygen may play an important role in the ignition mechanism by decreasing the activation energy necessary to kindle the reaction.
Evolving Non-Swelling Elastomers For High Pressure Oxygen Environments
Authors: Irani RS , Currie JL , Sanders J
Published: December 2008

The swelling characteristics of five specially designed elastomers under high pressure oxygen have been studied. The test programme has simulated actual service conditions and a number of variables such as gas pressure, temperature and moisture content have been systematically studied. The results which are interpreted with respect to the materials' structure and strength compare favourably with earlier work.
Surface Modification of Monel K-500 as a Means of Reducing Friction and Wear in High-Pressure Oxygen
Authors: Gunaji MV , Stoltzfus JM , Schoenman L , Kazaroff J
Published: December 2008

Tests were conducted to investigate the effects of surface treatments on the tribological characteristics of Monel K-500 being rubbed in high-pressure oxygen. The surface treatments investigated were ion-implanted oxygen, chromium, lead, and silver, electrolyzed chromium, and electroless nickel silicon carbide composite. The sample temperatures observed during frictional heating tests in ambient oxygen pressure were significantly higher than during tests at 6.9 MPa (1000 psi) oxygen pressure at the same loads and speeds. The ion-implant treatments reduced the average coefficient of friction at low contact pressure; however, this was eliminated when the contact pressure was increased from 5 to 20 kN/m2 (50 to 200 psi). Total sample wear was greater at 6.9 MPa (1000 psi) than at ambient oxygen pressure except when chromium was present. Electrolyzed chromium dramatically increased the total sample wear of Monel K-500 while other surface treatments affected sample wear only moderately. While some useful observations could be made from the data generated using this test apparatus, a different method must be developed if a more sensitive assessment of the effects of surface treatments on the tribological characteristics of Monel K-500 is required.
Evaluating Systems for Oxygen Service Through the Use of Quantitative Fault Tree Analysis
Authors: Santay AJ
Published: December 2008

In the event of a process plant upset, systems not normally intended for use in oxygen service may be suddenly subject to an oxygen-enriched atmosphere. If the upset condition occurs frequently, a conservative approach would be to design all components as if they were normally in oxygen service. As an alternative, one could calculate the probability of the upset condition to quantitatively assess the risk and recommend corrective measures to further reduce the risk. Quantified fault tree techniques are used to determine a system's compatibility when exposed to oxygen in this manner.
Adhesion of Fiber Metal Coatings
Authors: Andersen P , Levine DL
Published: December 2008

The strength of attachment of fibrous titanium pads to solid Ti-6Al-4V substrates was measured in tension and shear using both static and fatigue strength experiments. The static tensile strength ranged from 29.3 to 65.6 MPa, and the median 2-million-cycle tensile fatigue strength was 18.3 MPa. The static shear strength ranged from 51.7 to 83.2 MPa, and the median 2-million-cycle shear fatigue strength was 13.8 MPa. The tension specimens failed within the bulk of the pad, while the shear test specimens failed at the pad/substrate interface. Increases in either the processing temperature or the pressure applied to the specimen during diffusion bonding were found to increase the strength of the assembly.
Comparison of Measurement Methods for Characterization of Porous Coatings
Authors: Hamman G
Published: December 2008

A comparison was conducted of measurement techniques used to quantify porous coatings applied to implant surfaces for biological fixation. Four types of coatings were measured, which included two bead size ranges, one wire pad, and one plasma flame-sprayed coating.

The purpose of the study was to determine the relationships between the measurement techniques and their resultant values when compared using two-dimensional sections. Basic stereological principles were used in the approach to this study. An automated image analysis system was utilized in making the determinations. Pore size measurement was conducted using two methods: (1) a line intercept method with serial measurements conducted at multiple levels parallel to and in plane with the substrate surface and (2) an interactive user-defined region measurement, in which the evaluator determined which features within the structure constituted individual pores. Comparison of data from both measurement methods was made contrasting the line intercept with the user-defined measurements and the planar-section with the cross-section measurements. Average values for the percentage of porosity in each coating were compared. The values obtained on cross sections were compared with values obtained on planar sections; the results indicated that the volume fraction of porosity observed in the cross sections was reproducibly 5% higher than that measured in the planar sections.

In the pore size measurements, two measurement methods and two section planes were compared. The line intercept method data showed a general tendency toward a smaller pore size when compared with the user-defined pore size data. This trend was observed in the pore size measurements in both cross sections and planar sections. The automated line intercept measurement did not exclude minimum values; therefore, its population of very small intercepts appears to skew the average pore size toward a lower average.

The choice of measurement method and the section plane selection appear to have significant influence on the average values obtained when measuring pore sizes on two-dimensional specimens.
Fundamental Aspects of Load Transfer and Load Sharing
Authors: JB Koeneman
Published: December 2008

The objective of this review was to examine some of the critical design considerations for porous-surfaced ingrowth prostheses by looking at the fundamental aspects of load transfer and load sharing. It is shown that prostheses of lower stiffness provide higher average bone stress but can have higher stress concentrations in load transfer regions. There are a number of mechanisms for load transfer. Most load transfer, and thus bone hypertrophy, occurs only in localized regions.
Porous Polysulfone-Coated Femoral Stems
Authors: DeMane M , Beals NB , McDowell DL , Georgette FS , Spector M
Published: December 2008

Concerns about the metal ion release, high stiffness, and reduction in stem strength that are associated with porous metal coatings have prompted investigations of a relatively high-strength porous polymeric coating, porous polysulfone (PPSF). The present study was initiated in order to characterize the mechanical properties of PPSF and PPSF-coated titanium alloy and to evaluate the performance of PPSF as a coating on titanium alloy femoral stems in dogs. PPSF with various porosities was fabricated by sintering particles of Union Carbide P-1700 medical-grade polysulfone. Chemical coupling of PPSF to Ti-6Al-4V alloy specimens was achieved using silyl-reactive polysulfone. The shear strength of the PPSF/titanium alloy interface determined from push-out tests on coated cylindrical rods and transverse sections of the coated canine femoral stems was found to exceed 16 MPa. Tension and punch shear tests performed on the PPSF yielded values of 13 and 21 MPa, respectively. The relationship between strength and porosity characteristics was determined. Fatigue tests performed on PPSF-coated titanium femoral stems revealed no failure of the coating up to 1 million cycles. No difference between PPSF-coated and uncoated titanium specimens was found in the fatigue behavior. PPSF-coated titanium alloy canine femoral stems (32% porosity, 246 µm in average pore size) were implanted in 25 dogs. Evidence of loosening was found only in those animals in which the canal/fill ratio was low. No gross radiographic changes were found in the implanted femurs within the two-year postoperative period. Histology showed bone ingrowth fixation of the prostheses. Results of this investigation indicate that PPSF-coated femoral stems warrant continued investigation.
Grafts of HTR Polymer Versus Kiel Bone in Experimental Long Bone Defects in Rats
Authors: Binderman I , Goldstein M , Horowitz I , Fine N , Taicher S , Ashman A , Shteyer A
Published: December 2008

Gaps were prepared surgically in femora of 42 albino rats, and were kept apart by a looped wire. Grafts of Kiel bone (KB) and HTR™ polymer in different environments were implanted into those gaps. The control groups showed a nonbony healing 36 days after the osteotomy. KB or HTR polymer alone failed to induce bone bridging, while KB with autologous bone marrow induced bone bridging in the gaps. The most significant finding in this study was the ability of calcium hydroxide [Ca(OH)2] grafted with either KB or HTR polymer to cause differentiation of bone matrix in the surgical gaps. The combination of HTR polymer and Ca(OH)2 induced formation of trabecular bone bridging to a greater extent than all the other material combinations.
Protocol for Field Tests of Ultrasonic Devices for Rodent Management
Authors: Jackson WB , McCartney WC , Ashton AD
Published: December 2008

Testing ultrasonic devices for rodent repellency in closed environments results in contradictory responses. Without alternative environments, such efficacy tests cannot approximate actual conditions, and can result in erroneous conclusions.

Conducting observations in actual rodent-infested environments provides the best circumstances in which to measure the efficacy of high-frequency sound as a rodent management tool. Ideally, the installation of ultrasonic devices should be the only environmental variable. Rodent activity, measured with tracking patches, food consumption, or motion monitors before and after activation of units, is correlated with sound pressure patterns in the environment. Both frequency and sound pressure are important parameters. Preferably, two on/off cycles should be used.
Evaluation of Some Radioisotopes as Marking Agents for Monitoring Bait Consumption
Authors: Knowlton FF , Stoddart LC , Crabtree RL , Blatt JW
Published: December 2008

Minute quantities (1 to 20 μCi) of six gamma-emitting radioisotopes, manganese-54, zinc-65, selenium-75, iodine-125, iodine-131, and cesium-134, incorporated into nontoxic baits were found suitable as marking agents to detect bait consumption by coyotes (Canis latrans). The small quantity of isotope required minimizes detection of the marker by coyotes and potentially provides a bias-free procedure for simultaneously comparing the relative efficiency of several bait delivery techniques. Presence and identity of specific markers were determined with a multichannel analyzer on the basis of the energy level of emitted radiation. Differences in relative distribution of these isotopes among body tissues were noted. Other potential applications and constraints are discussed.
Vertebrate Pest Control and Animal Welfare
Authors: Schmidt RH
Published: December 2008

More than other types of wildlife management practices, vertebrate pest control activities elicit strong responses from the animal welfare community. The vertebrate pest control profession needs to become more aware of the concerns of this group, and sincere attempts must be made to incorporate their concerns in research and management practices. To assist in this task, recommendations for decision making to address animal welfare concerns for vertebrate pest control activities are given, along with a set of criteria for developing humane toxicants.
Interlaboratory and Intralaboratory Proficiency Testing
Authors: Horlick J
Published: December 2008

Proficiency testing is an integral part of the NVLAP laboratory accreditation process. Demonstration of appropriate facilities, equipment, personnel, etc. is essential, but may not be sufficient for the evaluation of laboratory competence. Inter- and intralaboratory test data using special proficiency testing samples provide the accrediting authority with a way to determine the operational competence of the laboratory.

For many test methods, results from proficiency testing are good indicators of a laboratory's testing capability. Information obtained from proficiency testing helps to identify and lead to solutions to problems in a laboratory. If problems with the test method are suspected, information can be provided to the appropriate standards-writing bodies to use as a basis for improving the method.

Each field of testing and each specific test method within a field has unique proficiency testing requirements. Proficiency testing data should be analyzed by the accreditor in confidence and summary reports of the results sent to the participants.
A Fractographic Study of Damage Mechanisms in Short-Fiber Metal Matrix Composites
Authors: Allen DH , Harris CE , Nottorf EW , Wren GG
Published: December 2008

A general constitutive theory is formulated for a short-fiber metal matrix composite. The constitutive theory is based on continuum mechanics with constraints provided by fracture mechanics and thermodynamics. The basic premise of the constitutive theory is that load-induced microstructural damage associated with the inclusion of the fibers in the metal matrix results in a loss of material stiffness.

The concept of the damage-dependent constitutive theory was evaluated by an experimental investigation of the microstructural damage in an Aluminum 6016-T6 matrix with silicon carbide (SiC) whiskers. The primary objective of the investigation was the identification of microstructural damage such as voids or cracks that were associated with the presence of the SiC whiskers.

The results of the experimental investigation include measured reductions in the elastic modulus of tension specimens which were loaded beyond yield and unloaded. Also, there was an associated change in the extent of the microstructural damage. These results lead to the conclusion that the effect of microstructural damage must be included in the constitutive relationship in order to fully describe the behavior of a metal matrix composite.
Fractography of Pressure Vessel Steel Weldments
Authors: Sankar J , Williams DB , Pense AW
Published: December 2008

An experimental program was carried out to interpret the effect of submerged arc flux compositions on the Charpy toughness and fracture behavior of typical pressure vessel steel weldments. Three different fluxes with varying basicity—namely, Linde Grade 80, Linde Grade 0091, and Oerlikon OP76—were selected for the program. The steel weldments used were C-Mn-Si, 214Cr-1Mo, and A543 Class 1. It has been found that silicon-rich inclusions are harmful to toughness and that Grade 80 welds with the presence of high amounts of these inclusions result in lower toughness compared to Grade 0091 or OP76. Of the three fluxes, OP76 develops a much cleaner weld with very few silicon-rich inclusions, resulting in extremely tough weld. Characterization of toughness at different positions of the weld shows sensitivity of the toughness tests on the weld metal to impact test position.
Fractographic Aspects of the Effect of Environment on the Fatigue Crack Propagation Mechanism in a High-Strength Aluminum Alloy
Authors: Ranganathan N , Bouchet B , Petit J
Published: December 2008

Fatigue crack propagation tests were conducted in three different environments, air, vacuum, and high purity nitrogen (N2) [3 ppm water vapor (H2O) + 1 ppm oxygen (O2)], on a high-strength aluminum alloy, 2024-T351. From tests conducted at a load ratio of 0.5, a typical behavior in the N2 environment is brought into light. At moderate ΔK-values, the crack growth behavior in N2 is similar to that observed in vacuum. As ΔK decreases, the crack growth curve shifts towards the one obtained in air showing a progressive environmental effect occurring in the presence of traces of water vapor.

The fractographic observations for these tests show that the environmental effect observed in the crack growth curves is accompanied by changes in the fracture surface morphology.

The observed results are discussed considering an energy-based model and by taking into account a discontinuous crack growth mechanism at low growth rates.
In-Reactor Deformation of Zr-2.5 wt% Nb Pressure Tubes
Authors: Causey AR , Fidleris V , MacEwen SR , Schulte CW
Published: December 2008

Changes in shape of internally pressurized tubes caused by operating temperatures and pressures are enhanced by fast neutron irradiation. Lengths and diameters of Zr-2.5 wt% Nb pressure tubes in CANada Deuterium Uranium-Pressurized Heavy Water (CANDU-PHW) power reactors and test reactors have been monitored periodically over the past 15 years. Axial and transverse strain rates have been evaluated in terms of the operating variables and the crystallographic texture and anisotropic microstructure of the extruded and cold-drawn tubes. The anisotropic deformation can be described by models for creep and irradiation growth in which the anisotropy factors are calculated from texture. It is assumed that prismatic slip is the dominant creep mode and that growth occurs by net fluxes of interstitials to a nonrandom distribution of 〈a〉 type edge dislocations and vacancies to 〈a〉 type screw dislocations, 〈c〉 type edge dislocations, and grain boundaries. The equations based on data from the Pickering Generating Station and WR1 test reactors give good agreement with measurements on internally pressurized tubes in Bruce Generating Station and the National Reactor Universal (NRU) test reactor and uniaxially stressed specimen in NRU.
Impurity Element Effects on the Toughness of 12 Cr-1 Mo Steel
Authors: Rou SH , Harrelson KJ , Wilcox RC
Published: December 2008

The effects of the trace impurity elements, phosphorus, sulfur, and silicon, on the impact toughness of a 12 Cr-1 Mo steel were investigated. The results of Charpy impact tests showed that the additions of all three elements produced an increase in the ductile-brittle transition temperature and the addition of phosphorus or sulfur caused a decrease in the upper shelf energy. Impurity segregation is used to explain the effect of phosphorus. The higher silicon concentrations produced increased amounts of delta ferrite, which is detrimental to toughness. Sulfur promotes nonmetallic inclusions and delta ferrite, both of which can result in embrittlement.
J-Integral Toughness of Low Fluence Neutron-Irradiated Stainless Steel DIN 1.4948
Authors: De Vries MI
Published: December 2008

Small compact-tension specimens of stainless steel German Industrial Standard (DIN) 1.4948, which is similar to American Iron and Steel Institute (AISI) Type 304, have been irradiated in the high flux reactor (HFR) at Petten up to a fluence level of 2 × 1024 n · m−2 (E > 0.1 MeV) at 823 K. Post-irradiation J-integral toughness tests have been performed with constant displacement rates ranging over four decades from 10−8 to 10−4 m · s−1 at the irradiation temperature.

The test method is based on a combination of the multiple-specimen interrupted loading method with the direct current potential drop technique (DCPD) for continuous monitoring of the crack length. The J,R curves, obtained by this method, show good reproducibility, and consequently the scatter of the J-toughness parameters is small.

The irradiation caused modest reduction, by about 30%, of the characteristic J-toughness parameters J0,3 and dJ/da at the displacement rate of 2 × 10−6 m · s−1. Low toughness values were measured at the lowest applied displacement rate. Results from additional tests showed that the effect of (slow) prior-fatigue loading at the low frequency of 10−2 Hz is minor compared to the effects of the lower displacement rates.
Experimental Assessments of Notch Ductility and Tensile Strength of Stainless Steel Weldments After 120°C Neutron Irradiation
Authors: Hawthorne JR , Menke BH , Awadalla NG , O'Kula KR
Published: December 2008

The Charpy-V (Cv) properties of American Iron and Steel Institute (AISI) 300 series stainless steel plate, weld, and weld heat-affected zone (HAZ) materials from commercial production weldments in 406-mm-diameter pipe (12.7-mm wall) were investigated in unirradiated and irradiated conditions. Weld and HAZ tensile properties were also assessed in the two conditions. The plates and weld filler wires represent different steel melts; the welds were produced using the multipass metal inert gas (MIG) process. Weldment properties in two test orientations were evaluated. Specimens were irradiated in a light water cooled and moderated reactor to 1 × 1020 n/cm2, E > 0.1 MeV, using a controlled temperature assembly. Specimen tests were performed at 25 and 125°C.

The radiation-induced reductions in Cv energy absorption at 25°C were about 42% for the weld and the HAZ materials evaluated. A trend of energy increase with temperature was observed. The concomitant elevation in yield strength was about 53%. The increase in tensile strength in contrast was only 16%. The postirradiation yield strength of the axial test orientation in the pipe was less than that of the circumferential test orientation.

Results for the HAZ indicate that this component may be the weakest link in the weldment from a fracture resistance viewpoint.
Hydrogen Buildup in Irradiated Type-304 Stainless Steel
Authors: Jacobs AJ
Published: December 2008

Type-304 stainless steel (SS), irradiated to a range of fast (E > 1 MeV) neutron fluences (1.90 × 1018 to 9 × 1021 n/cm2) in several different boiling water reactors, was found to contain ≥3 times as much hydrogen as unirradiated material. Hydrogen buildup in irradiated Type-304 SS was independent of fluence and flux in the range of fluences and fluxes investigated. This study was conducted as part of an investigation of irradiation-assisted stress corrosion cracking (IASCC). The accumulation of hydrogen in irradiated Type-304 SS may exacerbate the irradiation-induced loss of ductility, thereby increasing susceptibility to IASCC, or it may contribute to IASCC by other means.