bluuebunny/crossref_metadata_2025 huggingface dataset:
Where are the handouts?
Authors: Crean John
Published: March 2009

Over the last 10 years, influences from across the Atlantic and mainland Europe have forced those involved in organising learning opportunities to reconsider the place of teacher-led learning. The trend toward a student-led approach has an increasing number of UK-based advocates, whose focus is to facilitate self-directed community-based learning.
Infection control workshops for the whole dental team
Authors: Hook Melanie
Published: March 2009

Infection control is of paramount importance for all health care providers and service users in private and NHS practice; daily, stories are published in the scientific and wider press highlighting or raising concerns on hygiene or cleanliness and infection control. All of the dental team have a responsibility to develop and assess their skills and knowledge. Since compulsory continuing professional development (CPD) for dental care professionals (DCPs) was introduced last year, the FGDP(UK) workshops have risen to the challenge, offering CPD-based learning for the integrated dental team without detracting from the daily workload and responsibilities.
Natural orifice transluminal endoscopic surgery
Authors: Parker MC
Published: March 2009

Natural orifice transluminal endoscopic surgery (NOTES) is the latest experimental minimally invasive technology being investigated internationally for human use. The technique involves accessing the abdominal and other cavities without actually puncturing the abdominal wall but by using body cavities such as the rectum, vagina, bladder and stomach. The philosophy behind the research is based on improved cosmetic appearance, less pain, reduction in the likelihood of MRSA and the concept that human ingenuity and technological advance can continue to reduce the trauma and discomfort of effective surgery.
The “Hijacking” of Moral Conscience from Pharmacy Practice: A Canadian Perspective
Authors: Alarcon Cristina
Published: March 2009

The new vision for Canadian pharmacy practice, as outlined in the Blueprint for Pharmacy, drives for a more patient-centered and outcomes-focused approach to patient care than ever before. As of 2007 and 2009, pharmacists in Alberta and British Columbia, respectively, have the ability to adapt and renew existing prescriptions without prior approval from the physician. This necessarily puts a greater emphasis on the practice of pharmaceutical care, entailing the formation of a closer professional, more personalized bonding between pharmacist and patient. No one, however, seems to be paying much attention to the greater moral and ethical responsibility of pharmacists as they take on expanded roles. Not only are the greater expectations not coupled with greater respect for the pharmacist's freedom of conscience, but provincial jurisdictions across the country vary in degrees of tolerance toward pharmacists whose views differ from those held by the licensing authorities.
A New Principle for Measurement of Cobalamin and Corrinoids, Used for Studies of Cobalamin Analogs on Serum Haptocorrin
Authors: Hardlei Tore Forsingdal , Nexo Ebba
Published: March 2009

Background: Transcobalamin (TC) and haptocorrin (HC) are serum corrinoid–binding proteins. We developed new methods for measurement of the corrinoids bound to HC and TC.

Methods: TC (n = 10) or HC (n = 138) was immunoprecipitated, and corrinoids were released by enzymatic degradation [subtilisin Carlsberg (EC 3.4.21.62)] of the binding proteins. Binding of the released corrinoids to added unsaturated TC (apoTC) or HC (apoHC) created holoTC (as measure of cobalamins) and holoHC (as measure of corrinoids). holoTC and holoHC were measured by use of ELISA. The amounts of analogs were calculated as the difference between corrinoids and cobalamins. Corrinoids extracted from HC were separated with HPLC after addition of potassium cyanide (n = 3).

Results: The corrinoid- and cobalamin-specific assays had a positive linear relation between analyte concentration and assay signal, detection limits of 8 and 4 pmol/L, and imprecision values (CV) of ≤10% and ≤13% for concentrations between 45–200 and 12–115 pmol/L, respectively. No analogs were bound to serum TC, whereas the mean (95% reference range) for analogs present on HC was 245 (100–380) pmol/L. On HPLC a substantial amount of the analogs showed elution patterns similar to those of dicyanocobinamide.

Conclusions: Our methods for measurement of unmodified corrinoids in serum demonstrate that HC carries cobalamin analogs not recognized by TC, and that on HPLC a substantial part of these analogs elute similarly to cobinamide.
Media events and European visions: Czech Republic in the 2007 Eurovision Song Contest
Authors: Štětka Václav
Published: March 2009

In this article, the author deals with the relationship between the supposed socio-integrative role of media events, as defined by Dayan and Katz, and the processes of European integration and identity building. He focuses specifically on the Eurovision Song Contest and the way it has been historically promoted as a tool for raising European consciousness, as well as on the difficulties with maintaining this role in the context of the growing number of participating countries. These issues are further explored through an empirical analysis of the 2007 Eurovision Song Contest in the Czech Republic, which was a debuting country that year. This case study shows that the event was largely unsuccessful and met both with a lack of audience interest as well as with media criticism and even disdain. It also demonstrates how, in light of the Czech musical representative's failure in the ESC, the Czech media scene adopted a nationalist-defensive stance and created an image of a moral victory over decadent Europe.
Sexual attitudes and erotophobia and the recall of sexual content on television
Authors: Furnham Adrian , Hiranandani Mansha
Published: March 2009

Individuals' sexual attitudes and their level of erotophobia/erotophilia was related to their recall of sexual and non-sexual television adverts embedded within programs, with and without sexual content. Eighty-eight participants aged between 18–26 were placed in one of four conditions and shown ‘Sex and the city’ (sexual program) or ‘Friends’ (non-sexual program) with embedded sexual or non-sexual advertisements. There was a main effect of program type and advertisement type. Advertisement recall was hindered in the sexual program compared to the non-sexual program and sexual advertisements were recalled more than non-sexual advertisements. Those with liberal sexual attitudes and erotophiles showed lower recall of sexual advertisements. Limitations of the study are considered.
The analog switch-off in a cable dominated television landscape. Implications for the transition to digital television in Flanders
Authors: Verdegem Pieter , Hauttekeete Laurence , De Marez Lieven
Published: March 2009

Flanders will complete the migration from analog to digital terrestrial television by the end of 2008. Despite the cable dominated television landscape, the Flemish government is aiming at a smooth transition from analog to digital terrestrial television. Therefore, a multi-methodical study (quantitative survey and qualitative focus group interviews) has been set up by order of the Flemish government to understand the specific features and needs of analog antenna viewers and their expectations for the analog switch-off. The study shows that there are three distinctive types of analog antenna viewers. The results demonstrate that the antenna viewers are rather badly informed about the upcoming analog switch-off, which may lead to a negative attitude and may impede a smooth transition. Finally, antenna viewers seem to be rather conservative viewers: they wish to keep on watching the same television programs from the same channels. Moreover, digital terrestrial television is their preferred alternative.
Electrochemical Impedance Spectroscopy Measurement during Cathodic Disbondment Experiment of Pipeline Coatings
Authors: Papavinasam Sankara , Attard Michael , Revie R. Winston
Published: March 2009

Modified cathodic disbondment (CD) experiments were carried out over a period of 14 months using 13 coatings used to protect the external surfaces of oil and gas pipelines. During the experiments, electrochemical impedance spectroscopy (EIS) data were recorded, and after the experiments the cathodic disbondment area was measured. From the EIS data, the increase in coating capacitance was determined. Based on the comparison of coating capacitance values obtained from EIS data with the cathodic disbondment data, the coatings were broadly divided into three types: (1) high-performance coatings that did not disbond despite increasing coating capacitance; (2) poor-performance coatings that disbonded more than predicted from the increase in coating capacitance; and (3) average-performance coatings that disbonded at a rate proportional to the increase in coating capacitance.
Critical Appraisal of Fracture Mechanics
Authors: Weiss V , Yukawa S
Published: March 2009

A critical review of the basic premises of fracture mechanics is presented. The applicability of the theoretical concepts developed by Griffith and considerably expanded by Irwin and co-workers to materials testing and the determination of a unique and characteristic value of “fracture toughness” is examined. Finally, the usefulness and limitations of sharp crack fracture mechanics to the solution of engineering design problems are discussed.
Stress Analysis of Cracks
Authors: Paris PC , Sih GC
Published: March 2009

A general survey of the results of elastic stress analyses of cracked bodie is the basic objective of this work. The stress-intensity-factor method ofs representing results is stressed and compared with other similar methods. All three modes of crack-surface displacements are considered, as well as specialized results applicable to plate and shell bending. Results for various media (for example, anisotropic, viscoelastic, or nonhomogeneous) are contrasted with the analysis of homogeneous isotropic media. The accuracy of the representation of the crack-tip stress fields by stress-intensity factor methods is discussed, pointing out some limitations of applicability. Methods of estimating and approximate analysis for stress-intensity factors in complicated practical circumstances are also discussed.
Plasticity Aspects of Fracture Mechanics
Authors: McClintock FA , Irwin GR
Published: March 2009

Fracture mechanics, broadly speaking, represents knowledge of the influence of loading and geometry on fracture. Figure 1 shows the size range of significant events involved in the crack-extension process. Until the ion and electron cloud configuration shown schematically at the far left can be analyzed from wave mechanics, and the results integrated through ten orders of magnitude, it will be necessary to work with a series of different models, each appropriate to its own size range. Boundary conditions for each model are found from the next largest and next smallest scales. The smaller the size of the model from which we can integrate through larger sizes to obtain the fracture load for a given geometry, the broader the range of conditions which can be predicted or correlated from given experimental data. From whatever level we do start, it will be necessary to introduce test data to substitute for lack of knowledge (or cost of analysis) in the smaller regions.
Fracture Toughness Testing Methods
Authors: Srawley JE , Brown WF
Published: March 2009

A comprehensive survey is presented of current methods of fracture toughness testing that are based on linear elastic fracture mechanics. General principles are discussed in relation to the basic two-dimensional crack-stress field model, and in relation to real, three-dimensional specimens. The designs and necessary dimensions of specimens for mixed mode and opening mode (plane-strain) crack toughness measurements are considered in detail. Methods of test instrumentation and procedure are described. Expressions for calculation of crack toughness values are given for the common types of specimens.
Evaluation of Proposed Recommended Practice for Sharp-Notch Tension Testing
Authors: Heyer RH
Published: March 2009

The objectives and limitations of the proposed recommended practice for determining sharp-notch strength of high-strength sheet materials are given. Two specimen designs are used: 3 in. wide with sharply machined edge notches, and 3 in. wide with a center slot extended in both directions by fatigue cracking. Evaluation test results are reported for sharp-notch strength of four materials: aluminum alloy 7075-T651, titanium alloy 4Al-3Mo-1V, maraging steel 18Ni-9Co-5Mo, and precipitation-hardening stainless steel PH 14-8 Mo.

Test data from seven laboratories are analyzed for differences among laboratories and between the two specimen designs. Agreement among laboratories is generally satisfactory considering inherent difficulties in preparing sharply notched specimens to the close tolerances required. Data from specimens out of tolerance after machining or after fatigue cracking were rejected. Center-cracked specimens have significantly higher sharp-notch strengths than edge-notched specimens in tests on the aluminum alloy and the precipitation-hardening stainless steel.

Test specimens 8 in. long are suggested as alternates for the recommended 12-in. long specimens when insufficient material is available. Significant differences in test results were obtained for the two lengths of specimens.
Electron Fractography—A Tool for the Study of Micromechanisms of Fracturing Processes
Authors: Beachem CD , Pelloux RMN
Published: March 2009

Uses of the electron microscope for the study of fracture surfaces and the subsequent formulation of models of fine-scale fracture mechanisms are demonstrated. Electron fractography is shown to be a valuable tool in obtaining a better understanding of fracture and in the analysis of service failures.

Various types of fracture surfaces produced by single-cycle overload and by fatigue in various materials are discussed in order to indicate the usefulness of this relatively new tool.

The scope of application in the general field of fracture research is indicated.
Applied Fracture Mechanics
Authors: Tiffany CF , Masters JN
Published: March 2009

Procedures for applying fracture mechanics to typical engineering problems are reviewed. Particular emphasis is placed on plane-strain fracture of materials used in fabrication of pressure vessels and booster cases. The major areas considered are: (1) material selection; (2) the estimation of structural life; and (3) the determination of nondestructive inspection acceptance limits. In order to treat these items properly, a brief discussion on the character of premature structural failure is presented, followed by a discussion on the selection of a fracture toughness specimen.

In the area of material screening and selection, it is shown that the required design tool is related, not to toughness alone, but also to the design stress level and the size of the structure. In the estimation of structural life and determination of nondestructive inspection acceptance limits, emphasis is placed on the use of fracture specimen test results and the stress-intensity concept to predict critical flaw sizes and subcritical flaw growth. Both cyclic and sustained stress flaw growth are discussed and comparisons made between specimens and pressure vessels. The value of the proof test is discussed with regard to determining the maximum possible initial flaw sizes in a pressure vessel.
The Application of Fracture Toughness Testing to the Development of a Family of Alloy Steels
Authors: Pascover JS , Hill M , Matas SJ
Published: March 2009

The use of fracture toughness in the development of the 9Ni-4Co alloy system is described in this paper. The primary concern during this study was the delineation of metallurgical trends rather than the generation of quantitative data. Thus, screening tests have been employed.

The particular test chosen for any study should have four characteristics: 1. be compatible with previous data 2. be reasonable in cost 3. reflect the section size anticipated for eventual service 4. have sufficient sensitivity to define the effects of the variables investigated.

High-strength steels were screened effectively with center fatigue precracked specimens. The thickness of the specimens was adjusted to fit a given toughness level. The sensitivity was greatest when the ratio of the nominal notch strength to the yield strength was between 0.4 and 0.8.

For tough materials at strength levels of 200 ksi and lower, the determination of valid plane-strain toughness values in the early stages of alloy and process development is impractical due to the large size of the required specimens. Precracked and standard Charpy impact specimens appeared to define usefully qualitative trends. However, in the final optimization programs, plane-strain fracture toughness specimens were used to obtain absolute fracture toughness numbers compatible with the best known state of the art.
Symposium on Effect of Water-Reducing Admixtures and Set-Retarding Admixtures on Properties of Concrete
Authors: Committee C-1  , Committee C-9
Published: March 2009

Description

Twelve papers discuss advances in this field of concrete construction
The Practice of Sampling Soil and Rock
Authors: Golder HQ
Published: March 2009

Sampling of soil and rocks is an engineering technique. This paper reviews the history of sampling and the present state of the technique for clays, sands, gravels, and rocks. The necessity of undisturbed samples is discussed as is, very briefly, the cost of sampling.
Effect of Sampling and Testing Techniques on the Shear Strength of a Glacial-Lacustrine Clay from Welland, Ontario
Authors: Conlon RJ , Isaacs RMF
Published: March 2009

The “lower stratified” zone of the clay deposits at Welland, Ontario, is a sensitive lacustrine clay of medium to high plasticity. This zone is of particular importance in the stability of clay slopes for the deep approach cuts of the Townline Road/Rail Tunnel currently being constructed to pass beneath the relocated Welland Canal. The undrained shear strength is a minimum parallel to the bedding in certain critical layers within the lower stratified zone, indicating that the critical stability surface would include a long flat portion along this bedding. As the economy of the project demanded the steepest possible slopes, it was judged necessary to obtain and test the best possible undisturbed samples. Data available allow a comparison of test specimens obtained from block samples, and 5 and 3-in. tube samples. These data demonstrate the need for good undisturbed samples, geologically representative samples (the critical layers within the lower stratified zone), and relevant laboratory testing (measuring the shear strength parallel to the bedding).

The paper raises two important points: (a) the degree to which the peak undrained shear strength obtained from tests on good undisturbed samples can be mobilized along a failure surface in a soil mass and (b) the effect on the shear strength of a weak layer in a stratified clay as a result of pore pressure equalization with adjacent dissimilar layers.
Use of Chemical Grouts to Sample Sands
Authors: Karol RH
Published: March 2009

Significant dislocations of grains always occur when granular materials are sampled by conventional methods. Relative motion of soil grains during the sampling process can be minimized or prevented by replacing the void fluid by a solid prior to sampling. Chemical grouts can be used for this purpose.

Equipment and techniques for placing the grout have been developed and tested in the field. Strata as fine as 1/16 in. thick, normally lost by conventional sampling, can be delineated by chemical grouting prior to sampling.

Limited data indicate a linear relationship between relative density and unconfined compressive strength of stabilized granular soils. Laboratory testing of fabricated stabilized samples at zero and maximum density defines the relationship. Testing of stabilized field samples then indicates relative density.
Effect of Sampling on Some Soil Characteristics
Authors: Milovic DM
Published: March 2009

Test results on Shelby, Piston, and Block specimens are presented for two sensitive slightly overconsolidated clays. The purpose of this study is to show the influence of sampling methods on some clay properties. The specimens were obtained from the depth of 2.2 m. The in situ plate loading tests also were carried out at the same depth with an 0.61-m-diameter plate. The rate of strain in the triaxial tests and the rate of loading in the consolidation tests were kept constant. This was done in order to eliminate, as much as possible, the influence of factors other than the sampling procedure. For the same reason only the results obtained from the specimens having almost the same initial water content and void ratio were taken into consideration.
Comparative Observations on the Use of the Pitcher Sampler in Stiff Clay
Authors: Morgenstern NR , Thomson S
Published: March 2009

Recent experience in the use of the Pitcher sampler is described, and modifications to it which have improved performance are noted. Block samples of till have been obtained from a depth of about 85 ft below the ground surface. The following properties were determined in order to compare the borehole samples with the block samples: (a) swelling pressure, (b) compressibility, (c) permeability, (d) undrained strength, (e) compressional wave velocity, and (f) classification indexes. While differences between the results of Pitcher samples and Shelby tube samples are detectable, they are small when compared with the differences between the results from block samples and borehole samples. Contrary to expectations, the block samples have lower strengths and higher permeabilities. It is concluded that the block samples are more disturbed than those obtained from boreholes. With regard to borehole methods, the Pitcher sampler is judged preferable because samples can be recovered from stiff clays and soft rocks with a higher recovery ratio and with greater ease.
Evaluation and Prediction of the Residual Strength of Center Cracked Tension Panels
Authors: Feddersen CE
Published: March 2009

The residual strength of center cracked tension panels is considered from a phenomenological perspective. A simple, direct analysis technique is derived from experimental observations and stress intensity factor concepts. A smooth, continuous stress-flaw size curve is generated over the full range of crack lengths and panel widths. Plasticity and finite width effects are accommodated in a manner simpler and more consistent for engineering purposes than the iterative procedures implicit in current theoretical models. The technique is verified by an analysis of data from a variety of sources. It is concluded that toughness indexes, in the form of stress intensity factors, are reliable indicators of fracture instability, as well as other damage levels. They can be analyzed and interpreted on an elementary format. It also is shown that width can be uncoupled as a parameter in cracked panel behavior.
Fatigue Crack Propagation in Stiffened Panels
Authors: Poe CC
Published: March 2009

Rates of fatigue crack growth were measured in fatigue tests of stiffened panels constructed with bolted and integral stringers. The panels with bolted stringers were made from 2024-T3 aluminum alloy sheet with either aluminum alloy or steel stringers. The stringers were attached to the sheet with interference fit lock bolts. Stringer spacing and stiffness were varied systematically in the construction of the panels. The integrally stiffened panels were made from 7075-T6 aluminum alloy sheet extruded with outstanding stringers.

The stress intensity factor, calculated by a previously developed method, is used to predict the crack growth rates for the stiffened panels. Fatigue tests were conducted on unstiffened panels to determine the relationship between the stress intensity factor and crack growth rate.

In general, the stress intensity factor correctly predicts the crack growth rates in panels with bolted and with integral stringers except when the cracks are long. In these cases, the measured rates are slightly higher than the predicted rates. Furthermore, the stress intensity factor correctly predicts the rates to be lower in the panels with stiffer and more closely spaced stringers and to be equal in panels with steel and with aluminum alloy stringers of equal stiffness. The bolted stringers reduced the crack growth rate significantly below that for an equally stressed unstiffened panel, whereas the integral stringers had no significant effect.
An Approach to Predicting the Growth to Failure of Fatigue Cracks Subjected to Arbitrary Uniaxial Cyclic Loading
Authors: Brussat TR
Published: March 2009

A general approach to prediction is discussed which would treat crack growth as a continuous stochastic process. Each different crack description and length would be a state in this process, with residual strength failure constituting the terminal state.

The specific theory necessary for crack growth prediction is discussed. The effective stress intensity variable developed by Walker for crack growth under tension-tension cycling is extended to compression-tension cycling. The use of this variable with constant amplitude data for prediction of crack growth under spectrum loading is described. A means of calculating the conditional probability of residual strength failure (given the predicted crack growth history) is outlined.

The prediction method is tested on a controlled set of laboratory data from large center cracked 7075-T76 aluminum panels. Constant amplitude data are used to predict crack growth under a randomized flight-by-flight load spectrum typical of a location on an aircraft wing. Agreement is found to be good despite evidence of mechanism differences between the constant amplitude and variable amplitude crack growth processes.
Initiation and Growth of Fatigue Cracks in and Residual Strength of the F-100 Wing
Authors: Graziano WD , Fitch GE
Published: March 2009

Full scale fatigue tests were conducted on the F-100 wing. Service connected fatigue failure data were collected and compared with test results. Test lives to initiate fatigue cracks are compared with predicted lives using Miner's rule of linear cumulative damage and by a method accounting for plasticity at the crack origin. Calculated failure stresses using the principles of fracture mechanics are compared with laboratory test failure data. Crack growth data measured during testing are compared with values predicted from the relation dl/dN versus ΔK, the range in the stress intensity factor. Modifications to the wing structure are described, and the resulting fatigue life improvement is presented.
Development of the Fail-safe Design Features of the DC-10
Authors: Swift T
Published: March 2009

The degree of damage tolerance used in the design of the DC-10 fuselage pressure shell is discussed with reasons for its selection. Analysis methods are presented for the prediction of the residual strength of damaged, stiffened panels, based on the matrix force solution of an idealized structure combined with fracture mechanics equations. The results of 20 different configurations are included. A description of the development test program to verify the analytical techniques and to substantiate the fail-safe strength of the fuselage shell is given together with the results for many of the tests.
The Ballistic Damage Characteristics and Damage Tolerance of Wing Structural Elements
Authors: Jensen JE
Published: March 2009

The damage and residual strength of 7075-T6 aluminum panels exposed to caliber 0.50 AP M2 gunfire was found to vary with projectile velocity, impact angle, and target thickness. Maximum damage occurred at low velocities and high impact angles. The strength of thin panels agreed closely with fracture theory because of their predominant cracklike flaws; conversely, the strength of thick panels was close to the material ultimate tensile strength because of the blunt flaw shapes. Damage and residual strength prediction models were developed from the test data for monolithic panels. Alternate design concepts consisting of laminated, planked, and spar cap stiffened panels were investigated. The laminated panels exhibited extensive petaling and star-type cracking and low residual strength. Planked and spar cap stiffened panels provided damage alleviation and crack arrestment with high preload stresses.
Crack Propagation in Helicopter Rotor Blades
Authors: Rich MJ
Published: March 2009

Design criteria are presented for the residual strength and life of fatigue loaded helicopter structures. The crack propagation rate methods and data are reviewed, and a bilinear semilog method is shown to be most accurate for predicting residual life. The methods developed are compared with full scale rotor blade fatigue data. The good correlation with test data demonstrates the value of fracture mechanics analysis for fail-safe design.
Field Practices in the Repair of Fatigue Damaged Jet Engine Components
Authors: Popp HG , Wilbers LG , Erdeman VJ
Published: March 2009

True rejuvenation of fatigue damaged material is not practiced in the aerospace power plant industry. Lack of knowledge on fatigue damage accumulation and lack of confidence in restoration processing have been the major barriers to its use. However, repair of fatigue damaged hardware is practiced widely in engine overhaul shops. Effectively, the three prime methods of: (1) removal of distressed metal, (2) replacement of the distressed area, or (3) repair welding can restore components to original condition. The unique ways in which these three methods are applied in jet engine overhaul are reviewed in sufficient detail to provide an appreciation of the techniques and provide information as to how they may be extended to other structures that sustain fatigue damage.
Symposium on Applied Radiation and Radioisotope Test Methods
Authors: ASTM Committee E-10
Published: March 2009

Description

Twelve papers cover potential uses for radioisotopes in testing procedures. Such topics as ring wear, grain boundary studies, soil testing, cement testing and testing of organic materials are covered
Evaporative Emissions—Which Volatility Factors Count?
Authors: Hurn RW
Published: March 2009

Several volatility parameters have been investigated in an experimental study of volatility/emission relationships. These volatility indexes include Reid vapor pressure and several distillation properties. The experimental data show that the fuel tank losses are related characteristically to one parameter while carburetor losses appear to be related to a different parameter. The effect of volatility upon exhaust emissions was investigated in connection with the evaporative loss studies, and it appears that these emissions also are related directly or indirectly to the volatility characteristics of the gasoline.

The experimental results are used to illustrate how the several losses are related to the respective volatility parameters.
Effect of Gasoline Characteristics on Automotive Exhaust Emissions
Authors: Doelling RP , Gerber AF , Walsh MP
Published: March 2009

Fuel modifications encompassing composition, volatility, and lead content are investigated as a means of reducing automotive exhaust emissions. Several test programs are summarized, and numerous conclusions are listed.
Minimizing Exhaust Emissions—A Realistic Approach
Authors: Faust WJ , Sterba MJ
Published: March 2009

Piston engines will be the dominant vehicular power plant for the next 20 years. Although modifications to engine design and operating conditions will reduce exhaust emissions substantially, catalytic exhaust-gas converters will be required to reach the extreme low levels of emission desired. Lead-free gasoline will be required to permit the catalyst to function properly for the desired mileage. The initial drop in gasoline octane number, due to omission of lead, will be recovered gradually by refinery process changes. Gasoline will become more aromatic, more isoparaffinic, and less olefinic, while being reduced in sulfur content.

The total content of polynuclear aromatics in the exhaust gas is shown to be not affected by a substantial increase in the aromatic content of the gasoline. Polynuclear aromatics in the exhaust are oxidized almost completely by catalytic converters.

Governmental actions, statements by the automotive industry, and statements by the petroleum industry are cited.
Gasoline Characteristics and Air Conservation—A Review of API Engine Fuels Studies
Authors: Burtner RE
Published: March 2009

Some suggested remedies for pollution of the air by automotive emissions have been changes in volatility and composition of the gasoline and the removal of lead antiknocks. Several programs have been run under the sponsorship of the American Petroleum Institute to investigate not only whether these changes would benefit cleaner air through lower emissions, but also the effects on performance of cars. This paper combines and summarizes these programs. Variations in volatility and its effect on emissions and starting and warm-up of the car are discussed. Different olefin concentrations are evaluated for their influence on total emissions and the reactivity of these emissions. The effects on emissions of removing lead antiknocks from gasoline, while maintaining performance qualities as defined by octane and volatility parameters, are analyzed.
General Discussion—The California Gasoline Correlation of Vehicle Pollution Control and Unleaded Gasoline Correlation Tests
Authors: Larson CM
Published: March 2009

The remarkable success that our century has witnessed in all fields of science, theoretical and applied, often betrayed us into optimistic dreams of progress. Recently, however, the use of the atom bomb, deadly pesticides, Apollo 5 pollution at blast off, equal to 6000 Boeing 707 Jetliners, etc., has raised many moral questions. Many of those who previously believed in automatic improvement of culture through science have been seized by a profound skepticism and now put their hopes in a return to prescientific past. Whether we share such hopes or not, we must admit that the reputation of science, even of human knowledge itself, is at stake. We have come to a crisis of confidence in scientific pursuits.
Preliminary Report on the AGARD Evaluation of Variables Affecting High Temperature Creep Results
Authors: Coutsouradis D , Faurschou DK
Published: March 2009

The Advisory Group for Aerospace Research and Development (AGARD), a NATO committee, engaged in an interlaboratory study of high temperature creep testing facilities and techniques. The program utilized factorial design and analysis. Nimonic 105 was tested at 900 C by 18 volunteer laboratories. Preliminary results have permitted statistical evaluation of interlaboratory variability and of the significance of some testing and material variables which affect creep results.
Apparent Lowering of Creep Rupture Life by Frequent Beam Leveling
Authors: Voorhees HR
Published: March 2009

Limited test results reported here and elsewhere suggest that frequent beam leveling may reduce observed rupture life under conditions where the specimen ductility is high. The magnitude of this effect is small compared to the influence of other factors.
Interlaboratory Program to Evaluate Present Pyrometric Practices in Elevated Temperature Testing
Authors: Korns JL
Published: March 2009

An interlaboratory program was organized by members of the ASTM-ASME Joint Committee on Effect of Temperature on the Properties of Metals, Subcommittee on Test Methods, to determine the consistency of temperature measurement that exists among laboratories conducting elevated temperature testing. An evaluation was made of one phase of the pyrometric practice applied, comparison of the temperature at the center of a tension specimen measured with a common reference thermocouple with the temperature of its surface using the method of thermocouple manufacture and attachment utilized by each participating laboratory. In order to simulate the normal heat losses experienced through conduction during elevated temperature testing, a typical specimen train was included. Additional clad Chromel-Alumel thermocouples, taken from a section of calibrated wire, also were provided for one time use only.

Each of the participating laboratories attached their thermocouples to the specimen and adjusted the temperature controller so that the attached thermocouples indicated exactly 1200 F (922 K). The emf of the common reference thermocouple then was measured using the same reference junction utilized in their normal practice. This procedure was then repeated using the calibrated thermocouples exposed for only one measurement.

The information that has been developed by the seven participating laboratories to date has shown more variation than was expected. The total range of reported temperatures for the common thermocouple was 11 F (6.1 K) and 18 F (10 K) for the single-use thermocouples.
Effect of Thermocouple Drift on Rupture Life at High Temperature
Authors: Voorhees HR
Published: March 2009

Rupture life of Waspaloy in four tests under 9050-psi stress at 1700 F nominal temperature tended to be longer when temperature was adjusted in accordance with the reading of a noble metal thermocouple than when Type K base metal thermocouples were used. Drift of the reading of the base metal thermocouples relative to that of an adjacent noble metal thermocouple did not exceed 3 F in tests of nearly 400-h duration.
A Method for Extrapolating Rupture Ductility
Authors: Goldhoff RM
Published: March 2009

The prediction of long time, elevated temperature properties of useful alloys is of great practical importance. Time-temperature parametric relationships for correlating short time strength and predicting the long time residual strength at temperature have been developed and verified in long time testing. Equal in importance to the residual strength, however, is the capacity for deformation prior to failure, and many applications would appear to be limited by this characteristic. The object of this paper is to present an approximate but useful method for correlating and predicting characteristic, smooth test bar ductility.

The essence of the method presented is to obtain data which contain rupture ductility in a form that leads to a consistent array which can be treated by parameter techniques. To this end the rupture elongation and rupture time are ratioed to form the average creep rate, which can be treated parametrically and, when combined with the usual stress rupture parameter, provides the elements of this simple technique.

Several sets of high temperature data are treated to illustrate the technique and compare the results with actual long time data. Some attempt is made to determine how well the method may be expected to work when few data points are available. Further, the method is adaptable to prediction of either elongation or reduction of area at rupture, and this too is illustrated in the text. It is suggested that the method, while approximate, can serve as a quality control tool and should, therefore, be useful to materials engineers.
Elevated Temperature Tensile Grips for Tubing
Authors: Paxton MM
Published: March 2009

A technique has been developed for conducting elevated temperature tension tests on a 4-in. tubular specimen. The new technique, utilizing commercially available compression fittings, has been used successfully for over 200 elevated temperature tension tests. The technique complies with all pertinent ASTM standards. Tension tests on tubing can now be performed in a manner comparable to procedures used for conventional solid specimens.
Plane Strain Fracture Toughness of Some Cryogenic Materials at Room and Subzero Temperatures
Authors: Vishnevsky C , Steigerwald EA
Published: March 2009

An investigation was conducted to measure the plane strain fracture toughness, KIc, of eight potential cryogenic service alloys at 75, -100, and -321 F. The test materials included 7039-T61 and 2021-T81 aluminum alloys, Ti-6Al-4V STA in both alpha+beta and beta processed conditions, and the following steels: ASTM A553-A, PH 13-8Mo (H 1150-M), HP 9-4-20, and 18Ni (200 grade) maraging.

Results include both fracture toughness and tensile data as a function of test temperature for each alloy, together with overall comparisons in terms of the plane strain crack size factor, (KIc/σys)2, versus yield strength and yield strength to density ratio.

In cases where valid KIc data could not be generated, the appropriate aspects of the ASTM Tentative Method of Test for Plane Strain Fracture Toughness of Metallic Materials (E 399 - 70T) are discussed.
Influence of Specimen Design in Plane Strain Fracture Toughness Testing
Authors: Hall LR
Published: March 2009

The influence of specimen design on plane strain fracture toughness (KIc) was studied by fracturing 2219-T87 aluminum and 5Al-2.5Sn ELI titanium alloy single-edge notched bend (SENB), single-edge notched tension (SENT), compact tension (CT), and surface flawed (SF) specimens at 72 F (295 K) in laboratory air, at -320 F (78 K) in liquid nitrogen, and at -423 F (20 K) in liquid hydrogen. Specimen thickness for all SENB, SENT, and CT specimens except titanium/room air specimens was approximately 2.5(KIc/σys)2 in. Specimen thickness for SF specimens ranged from 2.5(KIc/σys)2 to 0.25(KIc/σys)2. Relative orientations of crack propagation and rolling directions were identical in all specimens of a given alloy. For aluminum alloy specimens having thicknesses of 2.5(KIc/σys)2, SENB, SENT, and SF specimen tests yielded consistent fracture toughness values at all test temperatures whereas CT specimen tests always yielded lower fracture toughness. For titanium alloy specimens having thicknesses of 2.5(KIc/σys)2, SENB, SENT, CT, and SF specimen tests yielded consistent fracture toughness values at -423 F (20 K); at -320 F (78 K), fracture toughness values from SF specimen tests were significantly greater than those obtained from tests of other specimen types; at 72 F (295 K) no valid fracture toughness data were obtained. Both aluminum alloy SF specimen tests yielded consistent fracture toughness (KIE) values when both flaw depth and distance between flaw tip and back specimen face exceeded 0.5(KIE/σys)2.
Fracture of Thin Sections Containing Through and Part-through Cracks
Authors: Orange TW , Sullivan TL , Calfo FD
Published: March 2009

Current fracture mechanics theory is used to illustrate the effects of crack dimensions and material properties on fracture stresses for through-thickness and part-through cracks. The implication of the analysis for leak-before-burst design of pressure vessels is discussed.

The applicability of plane strain theory to surface cracks in thin metal sections was studied experimentally. Specimens containing surface cracks of various depths and lengths and specimens with through cracks in the same range of crack lengths were tested. Ti-5Al-2.6Sn ELI (0.06 and 0.11 in. (1.6 and 2.9 mm) thick), 2014-T6 aluminum (0.06 in. (1.6 mm) thick), and 2219-T87 aluminum (0.07 in. (1.6 mm) thick) were tested at -423 F (20 K); the 2219-T87 alloy was also tested at +70 and -320 F (300 and 77 K).

The fracture tests indicate that, when Irwin's plastic zone size is less than about one tenth of the uncracked ligament depth (thickness minus crack depth), surface crack fracture behavior is in agreement with plane strain theory. When the plastic zone is greater than the ligament depth, fracture stresses for surface crack specimens are nearly the same as for specimens with through cracks of the same original length.
Correlation of Fracture Toughness, KIc/, with Fractographically Derived Plastic Stretched Zone Width—a Report of Astm E-24/II Task Group
Authors: Brothers AJ , Hill M , Parker MT , Spitzig WA , Wiebe W , Wolff UE
Published: March 2009

This report describes the results of a Task Group effort of E-24 Subcommittee II on Fractography. It presents the results of a study to determine quantitative correlation between fracture toughness, KIc, and the fractographically derived width of the stretched zone preceding fracture in fracture toughness specimens. The correlation was obtained for two highstrength aluminum alloys, a 6Al-4V titanium alloy and a 18Ni maraging steel heat treated to a strength level range of 170,000 to 260,000 psi.

It is observed that the width of the stretched zone increases with increasing fracture toughness and material ductility, and exhibits good correlation with the calculated crack opening displacement, that is, the nominal displacement of the crack surfaces normal to the plane of the crack. The width of the stretched zone shows no apparent dependence on, or correlation with, material grain size. Features of the 7075-T6 alloy, for which fraetographic features were defined most clearly and documented most extensively, suggests that the stretched zone represents a region of local strain at the crack tip which forms on loading and prior to incipient cracking. The features of the transition from the stretched zone to the fracture region in this alloy suggests that fracture is induced primarily by achieving critical conditions beyond the crack tip, and is not simply associated with tearing at a critical crack tip strain level.
Application of Electron Fractography to the Study of High-temperature Cavitation in Tungsten
Authors: Farrell K , Stiegler JO
Published: March 2009

Because brittle fracture surfaces sometimes carry a clear imprint of the results of prior thermomechanical history of a material, electron fractography can be used to glean information on this history. This is particularly so for those high-temperature phenomena that involve the development of elimination of small holes in solids. Examples of such holes are sintering pores, creep cavities, and gas bubbles. If the matrix is brittle at low temperatures the holes can be exposed for detailed microscopic examination simply by snapping the specimen at low temperature. This requirement is satisfied in tungsten in which we have studied the crystallography and the growth rates of gas bubbles, the morphologies of creep cavities, and the mechanism of hot cracking in fusion welds.
Electron Fractography of High Temperature, High Strain Rate Fracture
Authors: Wilber GA , Bucher JH
Published: March 2009

It is shown that electron microfractography can be applied successfully to the study of high temperature, high strain rate fracture. Although the fracture surfaces exhibited some oxidation and thermal etching, the quality of the fractographs was adequate to identify the operative fracture modes for a variety of alloys and test conditions. Three alloys were studied: (1) a nickel base superalloy (Inconel 718), (2) an austenitic stainless steel (AISI 304), and (3) a low carbon steel (AISI 1008). High strain rate, hot tension tests were carried out in vacuum or in argon after direct heating to the test temperature and after cooling from a reheating temperature typical of actual hot rolling operations.

The hot ductility, as indicated by the reduction in area at fracture, is described in terms of various temperature-ductility ranges which cover incipient melting as well as normal hot working temperatures. Electron fractography was combined with metallographic observations to obtain a more detailed description of this hot ductility behavior. A variety of fracture modes were observed depending on the alloy and test conditions with examples of transgranular shear rupture, intergranular shear rupture, and brittle intergranular decohesion. Despite the high deformation temperatures, some of the fracture surfaces exhibited areas of cleavage and brittle interphase separation resulting from crack initiation at second phase particles. A description of the specific fracture modes in each temperature-ductility range is given for each alloy, and the reasons for the observed variations in hot ductility are discussed.