bluuebunny/crossref_metadata_2025 huggingface dataset:
Oxygen Effects on Void Stabilization in Stainless Steel
Authors: Seitzman LE , Kulcinski GL , Dodd RA
Published: December 2008

Void nucleation theories often require surface energies significantly lower than established values in order to properly model cavity formation in metals. Surface impurities can cause the necessary decrease in surface energy and oxygen, which can interact readily with surfaces, is an abundant impurity in many metals. This study indicates that oxygen is especially effective in stabilizing voids. The amount of oxygen necessary to stabilize void formation in ion-irradiated Type 316 stainless steel is calculated as a function of temperature. Voids can be stabilized by reducing the surface energy such that the void becomes the most energetically stable vacancy cluster defect up to a size of 100 vacancies (D = 1.3 nm in steel). In austenitic steel, voids are stabilized when the surface energy decreases from 2.2 to 1.0 J/m2. This level of reduction in surface energy could be accomplished by the chemisorption of oxygen, initially in solution, on void embryos that are formed in the early stages of irradiation. Calculations for a Type 316 stainless steel reveal that the required amount of free oxygen initially in solution to nucleate voids is a minimum of 4 appm at 550°C.
Comparison of Various Sink Strengths for Analyzing Radiation Creep, Growth, and Swelling
Authors: Nichols FA , Liu YY
Published: December 2008

The essential physics involved in the reaction-rate-theory analysis of radiation effects at temperatures where both vacancies and self interstitials are mobile is contained in the expressions used for the strengths of distributed point-defect sinks such as dislocations, cavities, and grain boundaries. These sink strengths have been obtained by various authors in distinctly different ways, thus giving rise to some possible confusion in comparing the various results. This is even more true with respect to the effect of interaction fields on these sink strengths, and the so-called bias factors or sink efficiencies have been defined in entirely different ways, thus rendering quantitative comparisons difficult. We present here a comparison of several procedures in the literature and attempt to make reasonable quantitative comparisons.
Microstructural Changes in Commercial Aluminum Alloys Caused by Irradiation with 800-MeV Protons
Authors: Singh BN , Lohmann W , Ribbens A , Sommer WF
Published: December 2008

Commercial Al-Mg and Al-Mg-Si alloys were irradiated in the Los Alamos Meson Physics Facility (LAMPF) with 800-MeV protons. The irradiation experiment was carried out at a temperature between 40 to 100°C to a dose level of ≤0.2 dpa. Post-irradiation microstructure and mechanical properties of these alloys have been investigated. For comparison, a parallel investigation was conducted on unirradiated reference specimens as well as on unirradiated annealed (981 h at 100°C, corresponding to time at temperature during irradiation) specimens. It was found that the cold-work microstructure in the Al-Mg alloy survives the thermal annealing treatment but dissolves during irradiation already at a dose level of ≤0.1 dpa. In the Al-Mg-Si alloy magnesium silicide (Mg2Si) type precipitates also survive the thermal annealing but dissolve during irradiation at a low dose level of ≤0.1 dpa. Post-irradiation mechanical testing demonstrated that the strength of these alloys is drastically reduced because of irradiation. The observed irradiation softening can be understood in terms of the observed microstructural changes caused by irradiation.
Microstructural Examination of 12% Cr Martensitic Stainless Steel After Irradiation at Elevated Temperatures in FFTF
Authors: Hsu C-Y , Gelles DS , Lechtenberg TA
Published: December 2008

A remelted 12% Cr martensitic stainless steel (HT-9) has been examined by transmission electron microscopy before and after irradiation in the Materials Open Test Assembly (MOTA) of the Fast Flux Test Facility (FFTF). The irradiation temperatures were 365, 420, 520, and 600°C with the fluences as high as 7.3 × 1022 n/cm2 (E > 0.01 MeV) or 34 dpa. The extracted precipitates from each specimen were identified using X-ray microanalysis and selected area diffraction. The precipitates in the unirradiated condition were primarily M23C6 carbides, which formed at martensite lath and prior austenite grain boundaries. During irradiation at elevated temperatures, small amounts of other phases formed, which were tentatively identified as the chromium-rich α′, the nickel-silicon rich G-phase, and the intermetallic Chi phase. Irradiation-induced voids were observed only in specimens irradiated at 420°C to a dose of 34 dpa; no voids were found for specimens irradiated at 365, 520, and 600°C (∼11, ∼34, and ∼34 dpa). These results are not in agreement with previous experiments in that voids have not been reported in this alloy at relatively high fluence level (∼67 dpa) following irradiation in another fast-spectrum reactor (EBR.II). This is, however, the first observation following FFTF irradiation. The present results indicate that cavities can form in HT-9 at modest fluence levels even without significant generation of helium. Hence, the cavity formation in this class of ferritic alloys is not simply caused by helium generation but rather more complex mechanisms.
Depth Profiling of Hydrogen Isotopes Implanted into TiC Crystals
Authors: Sato K , Yamaguchi S , Fujino Y
Published: December 2008

The concentration depth profiles of hydrogen isotopes implanted into titanium carbide (TiCx) specimens in the composition range of x = 0.50 to 0.96 have been measured using the elastic recoil detection analysis. The retention behavior of the implanted deuterium changes with the specimen composition; the deuteriums deposit near the projected range, and a saturation is eventually reached for the specimens with the composition close to stoichiometric TiC, while for the specimens with off-stoichiometric compositions they diffuse very fast away from the near surface region to the interior to attain the saturation. The experimental data of retention and isotopic replacement are compared with a simple model of local saturation and replacement.
Dose and Energy Dependence of Helium Ion Irradiated Monel-400
Authors: Pande BM , Anand MS , Agarwala RP
Published: December 2008

Monel-400 was irradiated with helium ions of energies varying from 2 to 3 MeV in Van-de-Graaff. Dose and energy dependence of surface damage was studied. A minimum dose, which gave rise to observable surface damage in Monel-400 at 2 MeV, was 5 × 1020 ions/m2. This increased to 7.5 × 1020 ions/m2 at 3 MeV. The present experiments resulted in the formation of exfoliations without observable blisters. There were repetitive layers of exfoliated area on irradiation to higher doses for all the energies.
A Standard for the Intercommunication of Computers in a Flexible Manufacturing System
Authors: McEwen SM
Published: December 2008

Typically the control architecture of a flexible manufacturing system (FMS), as part of an integrated manufacturing system (IMS), consists of a hierarchical structure of computers, most with differing duties and some with differing responsibility. At the lowest levels of the hierarchy are the FMS work stations or subsystems (machine tools, material handling system, chip handling system, etc.) and above that the FMS control computer (the host) with the general overseeing or management responsibility. The proper functioning of this control hierarchy requires the intercommunication of commands and data between the FMS control computer and the FMS subsystems. The controllers and computers used in FMSs are, however, manufactured by a number of different companies most, if not all, of which employ unique hardware plugs and electrical signal structures for communication of data from machine to machine. It is by way of this discussion that the need to develop and implement an FMS communication standard is justified.

The approach we have taken (and an outline for the paper) includes: (1) a survey of the difficulties in FMS intercommunication, (2) establishing the data that are likely to be transmitted within the FMS, (3) setting forth the framework for a communication standard that addresses points 1 and 2, and (4) describing current FMS industry efforts to design an FMS intercommunication standard.
Some Comments on the Crisis in Engineering and Engineering Technology Education
Authors: Merkel KG
Published: December 2008

The maintenance of a high-quality technological base in the United States is dependent upon adequately funded engineering programs in American colleges and universities. At the current time, many American engineering educators feel that their academic programs are in a state of crisis with respect to adequacy of resources.

A number of foundations associated with large American companies (Exxon, IBM, Amoco, and others) have provided funds designed to aid engineering education. Funded programs at the national level have been proposed in Congress.

At the present time, the current level of funding is still inadequate. It will take a national technological crisis to improve this situation.
Stress Intensity Factors for a System of Cracks in an Infinite Strip
Authors: Civelek MB
Published: December 2008

The plane elasticity problem is considered for an infinite strip containing arbitrarily arranged cracks. The method of solution involves representing cracks by continuous distributions of dislocations, and results in a system of singular integral equations. The geometry and other parameters may be arbitrarily specified, including the number, locations, angles, and lengths of the cracks as well as the loading parameters. The problem of a semi-infinite strip is solved by letting one of the cracks cut the strip through. Stress intensity factors are presented for various geometries and loadings.
Evaluation of Analytical Solutions for Corner Cracks at Holes
Authors: Heckel JB , Rudd JL
Published: December 2008

This paper evaluates four state-of-the-art stress intensity factor solutions for a single corner crack at a hole. The solutions considered are Newman and Raju's, Shah's, and Liu's one-dimensional and two-dimensional solutions. The analytical solutions are correlated with experimental stress intensity factors obtained using the James-Anderson backtracking technique. The analytical solutions are further evaluated through analytical/experimental correlations of subsequent crack growth lives and crack shape changes. The materials considered are polymethyl methacrylate (PMMA), which is a transparent polymer material, and 7075-T651 aluminum. Excellent correlations are obtained for Newman and Raju's as well as Shah's solutions. However, Liu's one-dimensional and two-dimensional solutions are unconservative.
Fracture Toughness Improvement in a Carbon Steel Due to Normalization
Authors: Macdonald BD
Published: December 2008

Quantification of the fracture toughness improvement in a carbon steel due to normalization was investigated using A516-70 (normalized) and A36 (as-rolled) specimens tested at −40 and −46°C, respectively. The A516-70 was in its Charpy transition range and the A36 was on its Charpy lower shelf. This precluded fracture toughness comparison based on ductile tearing. Plasticity considerations excluded the plane strain fracture toughness idealization, and variations in specimen thickness disallowed use of the crack-opening-displacement method. A previously developed three-dimensional finite element (3DFE) estimate of the plastic stress singularity strength at maximum load was used to index fracture toughness which was found insensitive to specimen thickness for those thicknesses examined. The fracture toughness of the normalized steel was 2¼ times that of the as-rolled steel. The 3DFE analysis of the plastic stationary crack indicated, for the tougher A516-70, crack profile blunting and curvature reversal. Through-thickness FE mesh refinement revealed a local maximum value of plastic stress singularity strength removed from the plate midthickness, which confirmed observations made by P. S. Theocaris using the method of caustics. The fracture toughness of A516-70 was predicted reasonably well by a Charpy transition toughness correlation. As expected, the transition regime fracture toughness of the A36 steel was not predictable from its Charpy lower shelf energy.
Experimental Methods for the Evaluation of Environmentally Assisted Cracking of Steel in Caustic
Authors: Rungta R , Leis BN
Published: December 2008

This paper explores several popular test types and techniques used to study environmentally assisted cracking (EAC) with a view to identifying those tests that yield consistent data for purposes of materials screening and design data development. Test types considered include corrosion fatigue, stress corrosion, and potentiodynamic polarization. The influence of mechanical variables (such as strain rate, frequency, stress ratio, magnitude of stress, and stress intensity) and environmental parameters (such as electrochemical potential) on EAC is discussed in light of slow-strain-rate and precracked specimen test methods. The data generated by these various test methods are evaluated for their utility in designing structures. Throughout, the vehicle for discussion is test results developed with these test methods in iron-caustic and steel-caustic systems. It is concluded that much remains to be done in regard to the development of standards that couple the influence of both mechanical and electrochemical parameters in a manner which reflects the range of possible service experience.
Use of a Load-Pulsing Technique to Determine Stress Corrosion Crack Velocity
Authors: Slattery PW , Smit J , Pugh EN
Published: December 2008

A load-pulsing technique has been used to determine the velocity of transgranular stress-corrosion cracks in Admiralty Metal tested in a 15N aqueous ammoniacal solution. In this technique, small load pulses are periodically superimposed onto an otherwise constant tensile load during crack propagation, producing markings on the fracture surfaces which delineate the positions of the crack front. The spacing between crack-front markings (Δx) was measured for values of the time interval between pulses (Δt) in the range 2 to 500 s. A one-to-one correspondence was observed between pulses and markings in this range, so that the crack velocity was given by Δx/δt. The velocity was found to be constant over much of the crack length for each value of Δt, indicating that an extensive Stage II region exists in this system. The Stage II velocity was constant: 1.9 × 10−7 m s−1 for values of Δt greater than 100 s; this value of velocity is approximately five times larger than those obtained by conventional methods, and this difference is attributed to the influence of grain boundaries in the latter case. The Stage II velocity increased with decreasing Δt for Δt < 100 s, and this is attributed to fatigue effects. It is concluded that the load-pulsing method can provide a convenient and reliable technique for the determination of Stage II velocities for transgranular stress-corrosion cracking.
Automated Corrosion Fatigue Crack Growth Testing in Pressurized Water Environments
Authors: Ceschini LJ , Liaw PK , Rudd GE , Logsdon WA
Published: December 2008

This paper describes in detail a novel approach to construct a test facility for developing corrosion fatigue crack growth rate (FCGR) properties in aggressive environments. The environment studied is that of a pressurized water reactor (PWR) at 288°C (550°F) and 13.8 MPa (2000 psig). To expedite data generation, each chamber was designed to accommodate two test specimens. A common water recirculation and pressurization system was employed to service two test chambers. Thus, four fatigue crack propagation rate tests could be conducted simultaneously in the pressurized water environment. The data analysis was automated to minimize the typically high labor costs associated with corrosion fatigue crack propagation testing. Verification FCGR tests conducted on an ASTM A469 rotor steel in a room temperature air environment as well as actual PWR environment FCGR tests performed on an ASTM A533 Grade B Class 2 pressure vessel steel demonstrated that the dual specimen test facility is an excellent system for developing the FCGR properties of materials in adverse environments.
On-Line Ultrasonic Inside-Diameter Control System for Zircaloy Tube Etching
Authors: Tanaka Y , Komatsu M , Fujii N , Kubota H
Published: December 2008

An ultrasonic inside-diameter (ID) control system was used during the final etching process for producing Zircaloy nuclear fuel cladding tubes. This results in establishing automatic inside-diameter control during etching with an automatic etching system.

In this system, the inside-diameter at the center point in the length of each tube is continuously measured with the ultrasonic inside-diameter measuring equipment during the etching process and the etching is automatically stopped by a signal from the control equipment when the inside-diameter reaches the target value.

This made the final etching process economical and suitable for large-scale production, having an equal or better level at the inside-diameter of tubes etched with this system than those made by a process controlled by an air-micrometer.
Flow Softening and Anneal Hardening in Two-Phase Zr-2.5Nb
Authors: Rizkalla AS , Choubey R , Jonas JJ
Published: December 2008

The flow properties of Zr-2.5Nb were determined in the (α + β) range at 998 and 1148 K, which corresponds to about 15 and 85 volume % β. The flow stresses were determined in axisymmetric compression at constant true strain rates ranging from 3.1 × 10−5 s−1 to 3.1 × 10−2 s−1.

The flow curves were characterized by a peak stress followed by considerable flow softening and, for strain rates less than 10−3 s−1, the flow stress for the large β-fraction materials dropped by only 25 to 30% of the peak stress as compared with 50 to 70% for the predominantly α-materials. The amount of flow softening also decreased with increasing coarseness of the prior α-plate morphology.

The α-plates rotated from an initially random to a distinctly transverse orientation, and at strain rates less than 10−3 s−1, the α-plate structure broke up to produce an equiaxed grain morphology. The strain rate sensitivity concurrently increased from 0.22 to 0.4.

Significant anneal hardening was observed in the predominantly or fully α-region after a β-heat treatment, the amount of which increased with time of holding in the β-region. The activation energy was approximately 140 kJ/mole, which is similar to that for the diffusion of niobium in β-zirconium. The anneal hardening is ascribed to the formation of niobium-rich clusters in the β-phase. These clusters seem to be retained in the α-phase on cooling. Part of the flow softening in the anneal-hardened material can be ascribed to declustering by deformation.
On the Short-Time Recrystallization of Zircaloy-4 Above 600°C
Authors: Bäro G , Wessjohann HG , Nicoll AR
Published: December 2008

Cold-worked and stress-relieved Zircaloy-4 with and without recrystallized grains (approximately 3%) was thermally shocked to temperatures between 600 and 800°C for up to 1, 10, 100, and 1000 seconds. The resulting changes in tensile properties at 343°C can be described very well using Hunt and Schulson's equation F=F0×exp{−2.08×1018×t×exp(−41550T)}

where

F = unrecrystallized fraction,

F0 = starting value of F,

t = annealing time, s, and

T = temperature, K.

With respect to in-reactor recrystallization it is argued that the activation energy of the recrystallization process under reactor conditions is as high as for unirradiated material, but that the driving force is altered because of the different defect structure due to the neutron flux. This may be described by introducing a fluence-dependent factor λ (φ) to be multiplied with the time t instead of a constant.
Orientation of Hydrides in Zirconium Alloy Tubes
Authors: Cheadle BA , Coleman CE , Ipohorski M
Published: December 2008

The effects of crystallographic texture, grain size and shape, and tensile stress on the orientation of hydride platelets in Zircaloy-2, Zr-2.5Nb, and Excel tubes have been studied using transverse ring and longitudinal tension specimens.

When the α grains are equiaxed, the hydride platelets precipitate either at grain boundaries or on the basal plane. A sufficiently high tensile stress perpendicular to the basal plane will precipitate the platelets perpendicular to the stress.

When the grains are thin and elongated, the platelets precipitate along the grain boundaries. When the basal plane normals are close to a longitudinal axis of the grains, a sufficiently high stress will precipitate the platelets perpendicular to the stress and the platelets will cut across the grain boundaries.
Correlation Between Fabrication Parameters, Microstructure, and Texture in Zircaloy Tubing
Authors: Moulin L , Reschke S , Tenckhoff E
Published: December 2008

Starting from the extrusion billet, different reduction sequences were used to fabricate tubing to the same final dimensions. The fabrication sequences varied in the reductions of area, wall thickness, and diameter and also in the number of rolling steps (five to three), corresponding to area reductions in the range from 38% to 90%. They included common reduction routines as well as experimental reduction procedures.

The microstructural properties and the corresponding textures were measured in each sequential pass for the as-rolled and for the annealed conditions, respectively.

The results show that the reduction parameters of the final step predominantly determine the microstructure and texture in the final tube. The parameters governing the texture development, such as the reductions in wall thickness, diameter, and area as well as the intermediate annealing conditions, are determined after each reduction step. Maximum intensities and spread of basal and prism pole orientations, f-factors, etc., describing the texture are correlated with the microstructural parameters, such as grain size, degree of recrystallization, and hardness.

After the final cold reduction step, different annealing temperatures were applied in order to follow up and correlate the changes in microstructure and texture for The final tube condition. The results of these measurements allow conclusions about the recrystallization kinetics, as a function of cold deformation, annealing temperature, and annealing time. Their correlation with the factors determining the texture, resulting from the investigated reduction parameters, lead to an understanding of the control and improvement of the properties of the final tube.
On the Texture Measurements for Zircaloy Cladding Tube
Authors: Kimpara M , Fujita K , Kakuma T , Nagai N
Published: December 2008

To determine the texture gradient through the tube wall of Zircaloy tubing quantitatively, a coupled method of the reflection technique with chromium K-alpha radiation and the transmission technique with molybdenum K-alpha radiation was examined. The absorption correction for the transmission technique was made by a solid specimen with random orientation, and the specimen was also used for determining the slit configurations of the techniques. It was confirmed that the coupled method gave the identical full pole figures and f-parameters to those obtained by the reflection method with composite specimens. The specimen preparation for the coupled method was easier than that for the reflection method.
The Interpretation and Analysis of Upper Shelf Toughness Data
Authors: Ingham T
Published: December 2008

The paper outlines the problems encountered in attempting to define a self-consistent upper shelf toughness data base for use in a generic study of the integrity of a light water reactor (LWR) pressure vessel. Multiple-specimen resistance curve JR data were examined to provide “best estimates” of static initiation fracture toughness Ki at temperatures corresponding to fully ductile upper shelf behavior. In some cases, this involved reassessment of published data. To provide information that should be typical of current commercial steel making practice, Ki temperature relationships were developed from a statistical analysis of those data for A533B-1 and A508-3 steels containing less than 0.010 weight % sufur.

Relatively few data exist for weld metals, but the available results indicated that the Ki temperature relationships derived for base metals should also be applicable when assessing the significance of defects located in welds of a modern LWR pressure vessel.

Lower bound slopes (dJ/da)LB to the available JR data for A533B-1 and A508-3 steels were also defined. These can be used in conjunction with the Ki temperature relationships to derive post-initiation toughness data for up to 2-mm crack growth. The data base was derived from linear JR analyses, and its relevance to upper shelf initiation toughness data derived from nonlinear (power law) JR analyses is considered. Different methods of estimating initiation toughness are discussed and proposals are made to simplify the interpretation of upper shelf toughness data.
Determination of JIc Values by the Double Clip-on Gage Compliance Method
Authors: Kagawa H , Fujita T , Akiyama T , Urabe N
Published: December 2008

As one of the candidates for the single-specimen method to determine the JIc value, the double clip-on gage compliance method (DCGC) was introduced. This technique is based on the concept of the rotational factor of the compact tension specimen. According to the DCGC method, the JIc value can be determined by using only two clipon gages on a compact tension specimen under monotonic loading. To examine the usefulness of the DCGC method, JIc values of several kinds of steel were determined by the DCGC method and were compared with JIc values obtained by the multiple specimen method described in ASTM and Japan Society of Mechanical Engineers (JSME) standards. The relationship between JIc values by the DCGC method and by the multiple-specimen method was discussed, and the industrial utility of the DCGC method was verified.
A Test Method for Measuring the Efflorescence Potential of Masonry Mortars
Authors: Isberner AW
Published: December 2008

Efflorescence of masonry construction is a natural occurrence when masonry is constructed in other than under normal conditions. Early age efflorescence may occur shortly after construction has been completed; late age efflorescence may occur if design and construction considerations and building maintenance are not properly attended. Efflorescence, once understood, is deemed beneficial toward identifying problems associated with building performance and indicating corrective action to be taken to remedy the situation.

An efflorescence test method for masonry mortars has been developed. The method is considered beneficial for isolating contributors toward efflorescence, be it adverse exposure conditions, cement retarders, or contaminated individual materials. The interpretation of test results allows isolation of contributing factors and remedial action. Practically, testing of masonry mortars will not guarantee that efflorescence will not appear on the surface of a structure.
A Method to Determine Efflorescence and Water Permeance of Masonry Mortars
Authors: Harris HA
Published: December 2008

A laboratory test procedure to measure the efflorescence and water permeance of masonry mortars is presented. Quantitative and qualitative values of the efflorescence growth compounds can be measured using a technique that accelerates their development in a controlled laboratory environment. Using this same simple test apparatus, a minor change in testing procedures will also provide quantitative data on the water permeance of masonry mortars.
A Study of Glazed Brick Durability Characteristics and Building Applications
Authors: Naish WM
Published: December 2008

The author's company has been manufacturing glazed brick for more than 50 years. From a review of quality control and independent testing laboratory records, it is evident that this product has consistently met ASTM Specification for Facing Brick (Solid Masonry Units Made from Clay or Shale) (C 216) standards for durability. In early 1981 the author initiated a research study to determine some of the characteristics used by architects and structural engineers in designing the exterior walls of a variety of successful buildings utilizing these glazed brick.

The data gathered demonstrate that glazed brick with durability characteristics such as those reported have been used (1) in exterior building walls having a variety of design criteria, (2) in buildings of differing sizes and end uses, and (3) in severe weather climates. The author goes on to discuss that some wall failures have occurred in buildings other than those reviewed in this study; to comment regarding his observations of some such failures; and to suggest ongoing research aimed at more clearly defining in-service conditions that contribute to wall failures.
A Laboratory Comparison of the Effects of Water and Waste Leachate on the Performance of Soil Liners
Authors: Eklund AG
Published: December 2008

A study was conducted to determine the performance of two compacted native soils and the soils plus a commercial additive when exposed to specific paper mill waste leachates. Fluids produced from actual paper mill wastes were used in accelerated (high-pressure), anaerobic permeability tests with two disposal site soils and the soils with a beneficient added. Comparison tests measuring hydraulic conductivity were performed to determine behavioral differences of the candidate soil liners with the waste leachate and water. Test results were used to evaluate waste impacts on soil and on the soil plus a commercial additive. Emphasis was placed on identifying fatal flaws in expected field linear performance.

Test results indicated that the two soils tested were effective in containing the paper mill waste leachates. One soil physically contained the waste leachates by providing an impermeable barrier (K = << 10−7 cm/s). The other soil, while not providing as strong a physical barrier, (K = 10−7 cm/s), did contain the leachate through chemical attenuation of the trace contaminants in the leachate. While the commercial additive improved the impervious barrier characteristics of this soil, it was determined to be optional. Both mechanisms of containment will be effective in providing protection of groundwater resources below a nonhazardous waste landfill.
Effects of Brine on the Soil Lining of an Evaporation Pond
Authors: Jones CW
Published: December 2008

Information is needed concerning the long-term effects of brine on the permeability of clay linings for salt-gradient solar and salt evaporation ponds. A case history is presented for the soil lining at Anderson Lake, New Mexico, which was operated as a brine evaporation pond from 1963 to 1976. The soil lining was sampled and tested in March 1982. At that time, the brine level was below the deposited salt surface and near the top of the lined area in the lake. From a comparison of the 1982 tests on the lining and preconstruction tests in 1962, the soil density appears to have increased slightly since lining construction, possibly due to effects of the brine on the soil. From approximate measurements of the drop in brine surface in 1982, the seepage through the lining appeared to be very low and was approximately one order of magnitude below the seepage determined during the first year of pond operation.
Road Roughness Effects on Vehicle Dynamics
Authors: Wambold JC
Published: December 2008

This paper is based on the Kummer Lecture presented in June 1983 to ASTM Committee E-17 on Traveled Surface Characteristics. It is intended to be a tutorial on the effects of road roughness on vehicle dynamics and is aimed primarily at those members of the highway community who generally are not versed in vehicle dynamics.

The paper first presents both a quarter-car and a half-car simulation, from which the various effects of road roughness can be used as input into the simulation to obtain various measures from the dynamic model. In particular, the acceleration of the sprung mass can be used, along with a standard such as the ride quality standard of the International Organization for Standardization (ISO), to establish the effects of a rough road on the ride quality of a vehicle. In a similar manner, the effects of a rough road can be applied to determine the energy loss by looking at the forces on the shock absorbers, while the loads transmitted back down through the tire to the pavement can also be investigated. Another application of the theoretical quarter-car model is that it can be used to determine the effects of vehicle dynamics on a road roughness meter, such as the Mays meter or the Portland Cement Association (PCA) meter. Finally, a quarter-truck model is presented to show the effects of roughness on a truck model, as opposed to the car model presented earlier.
Comparison of Environmental Effect and Biotransformation of Toxicants on Laboratory Microcosm and Field Microbial Communities
Authors: Portier RJ
Published: December 2008

The proper identification and laboratory analyses of relevant in situ parameters for determining the environmental effect and fate of toxicants in coastal wetlands are important components in validating laboratory microcosm procedures. Measurements of microbial density, phosphatase and dehydrogenase activity, adenosine triphosphate (ATP), fluorescin diacete hydrolysis, and the mineralization of toxicant parent molecules were evaluated both in the environment and under laboratory microcosm simulation for different pH/Eh, salinity, temperature, and sediment/water interface conditions. High correlations were established between control microcosms and field measurements. Fate and effect predictions were compared with field estimates for several toxicants.
Marine Fuels and International Standards
Authors: Thornton RH , Casale PG , Davidson D , Graham M
Published: December 2008

Problems attributed to marine fuel quality are increasing. Important factors influencing fuel quality are the type of crude oil refined and the refining processes it undergoes. Conversion steps such as visbreaking and catalytic (cat) cracking concentrate the less desirable characteristics in bunker fuel oil. Therefore, proper shipboard treatment of marine residual fuels is essential for reliable and efficient engine performance.

Intermediate marine residual fuels are still ordered by viscosity alone, but the work on international specifications for marine fuels is nearing completion. BSMA 100:1982 was published by the British Standards Institution (BSI) in 1983, and work is nearing completion by the International Organization for Standardization (ISO) on international standards. As a common reference, standards will be valuable, and their eventual adoption by the trade in the purchase and sale of bunkers is likely.
Evaluation of Shipboard Fuel Testing Procedures
Authors: Anderson FE , Burnett MW , Giannini RM , Kuby WC , Modetz HJ , Strucko R , Talbot AF
Published: December 2008

Currently, the U.S. Navy's preferred fuel for all fossil-fueled, surface ship power systems is a middle distillate fuel conforming to the requirements of MIL-F-16884H, Fuel, Naval Distillate (NATO F-76). In recent years, Navy ships have been finding it increasingly difficult to obtain F-76, especially in foreign ports, and this tightly specified fuel is generally more expensive than its civilian counterparts. To address the potential problem of reduced availability and to begin planning for the introduction of synthetic fuels such as shale oil products, the Energy Research and Development Office of the David W. Taylor Naval Ship Research and Development Center commissioned a shipboard fuels flexibility study. The overall objective of this program was to develop a comprehensive strategy for using a broadened specification fuel on board Navy ships.

As part of the shipboard fuels flexibility program, shipboard fuel testing procedures were evaluated that could be used by Navy personnel on board ship to judge the acceptability of fuels not procured under MIL-F-16884H. As such, the study was divided into three subtasks:

1. Evaluation of shipboard fuel testing procedures currently used on board Navy and commercial marine vessels.

2. Determination of fuel testing procedures required for shipboard screening of non-specification fuels and the adequacy of available procedures.

3. Recommendation of a test protocol and the development or refinement of additional shipboard fuel testing procedures.

This paper summarizes the results of those subtasks. Test protocols, which could be used for shipboard testing of nonspecification fuels obtained outside the Navy's fuel logistics system, are presented for:

1. Marine gas oil (MGO)—a middistillate fuel containing no residual fuel oil, the marine equivalent to Nos. 1-D and 2-D fuels.

2. Marine diesel fuel (MDF)—a middistillate fuel heavier than a marine gas oil, containing less than 10% residual fuel oil, frequently as a result of contamination.

3. Intermediate fuel oil (IFO)—a blend of heavy residual fuel oil and marine gas oil or marine diesel fuel.

The proposed procedures and instruments for each protocol are discussed as well as the sequence in which they would be performed. Manpower requirements, as well as the cost and space associated with each protocol, are reviewed. Areas where additional research or development are required are identified with recommendations for such activities.
Smoke Production in Fires: Small-Scale Experiments
Authors: Drysdale DP , Abdul-Rahim FF
Published: December 2008

The quantity of smoke released in a compartment fire depends both on the nature of the combustible materials involved and on the conditions of burning. The final yield of “cold” smoke is much greater than the quantity predicted from dynamic measurements of hot combustion products issuing from a test rig and is likely to be considerably more than the amount predicted from the results of small-scale tests such as Method for Specific Optical Density of Smoke Generated by Solid Materials (ASTM E 662–83).
A Statewide Program to Identify and Prevent Stripping Damage
Authors: Busching HW , Corley GC , Burati JL , Amirkhanian SN , Alewine JM
Published: December 2008

A statewide pavement coring and testing program was conducted in South Carolina to determine the extent and severity of asphalt pavement stripping. Information from extensive and intensive coring and testing programs identified causes of stripping so that effective measures could be developed to eliminate or minimize future damage. Stripping frequency was related to the following factors: highway, aggregate source, mix type, cross-section type, traffic group, pavement age, and presence of open-graded friction courses. Stripping was pervasive but of varying severity in all soil provinces. Results of findings from indirect tensile strength tests of pavement core layers and a visual examination are given. Strength retention of moisture-conditioned pavement core layers was measured for specimen cores obtained from the outer wheel path.
The Effect of Moisture on the Performance of Asphalt Mixtures
Authors: Kim O-K , Bell CA , Hicks RG
Published: December 2008

This paper presents the results of a laboratory study to investigate the effects of mixing moisture on mechanical properties of asphalt mixtures. The potential benefits of lime and Pavebond Special were also evaluated. The repeated load diametral test device was used to measure the mixture performance in terms of the resilient modulus, fatigue, and permanent deformation characteristics of laboratory specimens prepared with and without moisture (0, 1, and 3%) and with and without lime (1%) and Pavebond (0.5%). Mixtures were prepared that were representative of two projects for which considerable field data were available. One project utilized low quality and high absorptive aggregate and the other good quality aggregate. To evaluate the long-term durability of mixtures, they were tested before and after conditioning using the Lottman approach.

The test results showed that inferior performance occurred for mixtures with 3% moisture but was most pronounced in mixtures with higher air-void contents. However, the mixtures with low quality and high absorptive aggregate showed improved performance at 1% moisture content, associated with their lower air-void contents, which may be due to absorbed moisture preventing asphalt absorption and the higher asphalt content of these mixtures. The addition of lime resulted in distinct improvement of performance for moist specimens from the project, which had good quality aggregate, but high air-void contents. However, neither additive showed substantial benefit for moist samples from the project with low quality aggregate and low air-void content.
A Laboratory Study of the Effectiveness of Various Admixtures on the Attenuation of Moisture Damage Upon Various Foamed Asphalt Mixtures
Authors: Castedo H , Beaudoin CC , Wood LE , Altschaeffl AG
Published: December 2008

Durability characteristics of certain foamed asphalt mixtures were established during this laboratory investigation. Durability was characterized by a water sensitivity test and cyclic freezing and thawing. The various foamed asphalt mixtures were evaluated for durability after the mixtures had been compacted into 10.16-cm (4.00-in.) diameter by approximately 6.35-cm (2.50-in.) high specimens, and cured.

Durability effects of different variables were determined in this laboratory study. These variables were foamed asphalt content (two levels for water sensitivity section, one level for freeze-thaw section), aggregate (three types, used in both sections), additives (three types, plus a set without additives), and additive content (two levels for each additive in the water sensitivity section, one level for each additive in the freeze-thaw section). One asphalt type, one mixing and testing temperature, one set of curing conditions, and one moisture content per aggregate were used.

Resilient modulus and modified Marshall stability tests were used to monitor durability characteristics of the mix in the water sensitivity section. Durability in the freezing and thawing section was monitored by pulse-velocity, resilient modulus, and modified Marshall stability tests. When lime was used as an additive, durability, strength, and longevity of the foamed asphalt mixtures were substantially improved. The improvement achieved with the addition of lime was such that a material generally less suitable for bituminous mix, such as outwash sand or pit-run gravel, may rival a material more suitable for bituminous pavement mix such as crushed limestone.

During this study there were similar rates of decline per freeze-thaw cycle for pulse-velocity and modified Marshall stability. Pulse-velocity, a nondestructive test, appears to be related to the destructive modified Marshall stability method. There seemed to be a good reproducibility of pulse-velocity values among similar specimens.
On the Definition of Planes of Maximum Shear Strain
Authors: Fuchs HO
Published: December 2008

The concept of planes of strain is contrary to accepted definitions. “Planes of maximum shear strain” are defined as planes normal to the lines of maximum shear strain. They are the same as planes of maximum shear stress. The latter designation is unambiguous, simple, and in accord with accepted definitions. It is proposed that the designation “planes of maximum shear stress” be used unless it can be shown that planes of maximum shear strain are different from the former and more important as fatigue variables.
A Fatigue Test System for a Notched Shaft in Combined Bending and Torsion
Authors: Downing SD , Galliart DR
Published: December 2008

This paper describes the design of a two-channel test system that can generate combinations of torque and bending on a round notched specimen. The test frame consists of a specially designed set of hardware for the size and shape of the SAE Fatigue Design and Evaluation Committee's round specimen. The two RAM computer-controlled hydraulic closed loop system provides independent control for each RAM. Load cells and stroke transducers are mounted in-line to provide signals for control and data processing. In addition to a description of the hardware, this paper defines the software that is used to control the system and perform data analysis on five channels of data. The data consist of the two channels of load and three channels of strain from a rectangular rosette. An ultrasonic surface wave technique is used to detect a crack of defined size and automatically halt the test.
Multiaxial Fatigue Testing Machine for Polymers
Authors: Lawrence CC
Published: December 2008

Plastics are now increasingly used as engineering materials; consequently, there is a need to establish the propensity of the material to fail under fatigue loading. However, in general terms, conventional methods for establishing the fatigue life of a plastic component cannot be used, and alternative ways have to be found. Multiaxial and “in service” load simulation is suggested as a method of tackling this problem. The possibilities of this alternative technique are outlined, and, because of the peculiar and stringent demands on the design of the loading apparatus, this is discussed in detail. The evolution of this apparatus has led to the development of techniques that have solved many of the difficulties found in the application of a multiaxial load and, in addition, offer marked improvements in the field of testing plastics in general.
Comments on Fatigue Crack Growth Under Mixed Modes I and III and Pure Mode III Loading
Authors: Pook LP
Published: December 2008

Some features of fatigue crack growth under pure Mode III and mixed Modes I and III loading were examined, including two cases where the Mode III displacements are not proportional to the Mode I displacements. Information obtained under nominally elastic conditions for various commercial alloys was reanalyzed and discussed in the light of theoretical considerations to see whether consistent patterns of behavior could be identified. Despite some inconsistencies and anomalies it was found that a reasonably consistent pattern of behavior was beginning to emerge. In particular a tentative upper bound for the rate of fatigue crack growth was identified, but it does not apply to slant crack growth in thin sheets.
Smooth Specimen Fatigue Lives and Microcrack Growth Modes in Torsion
Authors: Hurd NJ , Irving PE
Published: December 2008

Constant amplitude torsional fatigue tests have been performed on smooth specimens of quenched and tempered steel at two strength levels. Both unidirectional and fully reversed tests have been performed. It was found that there was no detectable effect of mean strain upon fatigue life of either strength level material, both at short and at long lives. Observations on microcrack behavior during the tests has demonstrated that initial crack growth always occurs on a shear plane, even if subsequent propagation is on a tensile Mode I plane at 45°.

As in the uniaxial situation, short lives are dominated by microcrack growth. However, in torsion crack growth dominates over an extended range of life, and, in addition, surface crack lengths are longer than uniaxial at similar fractions of life. It is concluded that whereas crack initiation on shear planes is relatively easy in torsion, the Stage I/Stage II transition, which occurs in tension at crack lengths of one or two grains, is extremely difficult in torsion.