bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of Weibull Parameters for Composite Material Strength and Fatigue Life Data
Authors: Talreja R 
Published: March 2009

Two classical methods for estimation of Weibull parameters, namely, the moment estimation and the maximum likelihood estimation are reviewed. It is demonstrated that, assuming the location parameter to be zero, the errors made in estimating both the scale and the shape parameters by these methods increase linearly with the true value of the location parameter.
An alternative method for Weibull parameter estimation is proposed. This method provides estimates for all three parameters when the shape parameter is close to one, and estimates the scale and the shape parameters more accurately than the other two methods for higher values of the shape parameter. Furthermore, unlike the other methods, this method is capable of separating the constituent components in a multi-component sample and estimating the parameters of each component. This property makes the method suitable for statistical analysis of composite material strength and fatigue life data.
On Abrasion, Scratch, and Friction Testing—Relationship to End-Use Application
Authors: Carroll JF 
Published: March 2009

In the field of plastic testing, reproducibility is usually emphasized in standard test methods. However, relevancy is at least equally important to end-use applications. In the field of surface testing, relevancy can sometimes be more difficult to achieve.
Both ASTM and nonstandard abrasion tests for plastics are compared with ANSI abrasion tests for photographic film. Mechanisms include falling carborundum, abrasive loaded wheels, soft-hair wheelbrush, and spherical stylus. All give similar rankings when testing simple plastics surfaces. Only the spherical stylus produces results reliably related to trade experience with the thin coatings on photographic films.
Lubricity is introduced relative to its effect on abrasion resistance and ease of product handling by mechanical equipment. The classical ASTM friction test for plastics is a sled test. A sled test's lack of relevancy to scratch testing exemplifies a breakdown of the classical laws of friction. In the photographic film field, a point-contact friction test is more correlative. The ANSI version of this, the Paper Clip Friction Test, is described, and correlations with scratch as well as with lubricant levels in molded plastics are presented.
Stockpile Focus on Ferroalloys
Authors: Corder RE 
Published: March 2009

This paper deals with stockpiling of various ferroalloys in the National Defense Stockpile. The purpose and philosophy of stockpiling various forms of strategic and critical materials for national defense emergencies are discussed in addition to a historical review of the background and history of stockpiling various ferroalloys.
The methodology and econometric computer modeling used to calculate the overall stockpile quantities are described as well as the method used for calculating specific quantities of each ferroalloy. The potential pitfalls and problems associated with changes in specifications, industry usage patterns, and geographical shifts in production centers are included in the discussion.
The results of the use of the new methods and the effects on future stockpiling plans are presented.
Electrochemical Behavior of Carbon Steel in Fused Salts
Authors: Chen CM , Theus GJ 
Published: March 2009

The polarization resistance method was used to assess the corrosion rate and to study the oxidation kinetics of carbon steel in a fused nitrate-sulfate-chloride salt mixture at 316°C (600°F) and in an alkali iron trisulfate salt at 677°C (1250°F). The same method was also applied to estimate the corrosion rate of carbon steel through the solidified frozen alkali iron trisulfate salt.
Equilibrium potential/pO2− diagrams were constructed for iron, nitrate, and nitrate-reaction products to aid in the interpretation of corrosion data for the nitrate-rich salt and to determine the various chemical reactions causing the corrosion.
Titanium for Mechanical Equipment in Industrial Corrosion Service
Authors: McMaster JA 
Published: March 2009

Titanium usage in mechanical equipment for industrial corrosion service is increasing. The design and fabrication of this equipment requires special consideration to account for the fatigue properties and notch sensitivity of titanium, and maintainability of the finished equipment. Some weld metal properties, such as fatigue, are lower than similar properties for wrought products, and, therefore, welds should be properly contoured and located in low-stress areas.
Due to titanium's tendency for galling, threaded fasteners need thread coatings and are usually specified as loose fit. Using taper pins instead of straight pins and taking similar precautions also minimize the detrimental effects of titanium wear characteristics.
Improving the Corrosion Resistance of Zirconium Weldments
Authors: Frechem BS , Morrison JG , Webster RT 
Published: March 2009

Selective corrosion of zirconium Grade 702 weldments was observed in a process stream containing sulfuric acid at temperatures up to 150°C. Studies were conducted to determine the mechanism of the corrosion and to develop procedures for improving the corrosion resistance of the weldments.
Metallographic studies indicated that the dominant metallurgical factor affecting the selective corrosion is the presence and distribution of a second phase around the alpha grains. A simple heat treatment at 760 to 788°C disperses the second phase and significantly improves the corrosion resistance of the welds. The cooling rate was found to be critical only when temperatures are significantly higher than the recommended range.
Effects of Iron on the Corrosion Resistance of Titanium
Authors: Covington LC , Schutz RW 
Published: March 2009

This paper presents the results of extensive laboratory tests and experience in industrial applications to explain the effects of iron on the corrosion resistance of titanium.
In the great majority of cases where titanium is being used in corrosive environments, the effect of iron at the levels normally found in unalloyed titanium (⋍0.1 percent) is insignificant and has not led to any problems. However, in some cases, high solid-solution iron levels have been blamed for premature failures due to pitting or hydrogen embrittlement. Tests conducted at TIMET, Henderson, Nev., suggest that solid-solution iron has little, if any, effect on susceptibility to pitting or hydrogen embrittlement.
Iron particles embedded in the surface of unalloyed titanium are very deleterious. They serve as initiation sites for pitting and also as entry points for hydrogen.
Ferric ions in the corrosive solution are beneficial and serve as an excellent passivating agent for titanium. Iron oxide deposits on the surface of titanium also have a passivating effect.
Galvanic coupling of titanium and iron can lead to accelerated corrosion of the iron and, in some environments, to hydrogen embrittlement of the titanium. The magnitude of the effect is dependent on surface area ratios and the characteristics of the environment. Titanium, however, is being widely used successfully in applications where galvanic coupling with iron exists, with comparatively few problems being reported.
Trace Constituent Analysis for Metallic Systems: State of the Art
Authors: Javier-Son A 
Published: March 2009

The search for the right analytical technique for a particular element or elements is an ongoing challenge to an analytical chemist. The choice of a method is based on the concentration level of the analyte element, the matrix, the accuracy, the precision and speed desired, and in many cases, the economics involved. Thanks to many zealous workers, there are volumes of procedures to choose from. Oftentimes the concentration level and the matrix involved narrow down the choice to a few or none. Modification of existing analytical procedures is commonplace. When the analyte element or elements exist in trace quantities, the matrix effect plays an even bigger role, and the applicable analytical procedures are very limited.
This paper is essentially a comparison of analytical techniques available for trace analysis of metallic constituents of metals, alloys, and geological samples. The detection limit, accuracy, precision, and speed of analysis are discussed. The review centers on bulk analysis. The microanalysis, or in situ, techniques are not explored. The critique covers light absorption, atomic absorption, atomic fluorescence, and X-ray fluorescence spectrometric methods and activation analysis. The field of trace analysis for metals is currently dominated by atomic absorption procedures, particularly those employing electrothermal atomization. The plasmas, particularly inductively coupled plasmas, have demonstrated an explosive growth over the last 5 years. Utilization in analytical techniques is increasing exponentially, particularly in the areas of atomic emission and atomic fluorescence.
A Comparison of the Capabilities of Atomic Absorption and Inductively Coupled Plasma Spectroscopy for the Analysis of Metallurgical Samples
Authors: Wallace GF 
Published: March 2009

Three National Bureau of Standards aluminum brasses, Standard Reference Materials 1118, 1119, and 1120, were chosen as representative samples for a study comparing the capabilities of atomic absorption spectroscopy and inductively coupled plasma emission (ICP) spectroscopy for the determination of trace elements in metallurgical samples. The results for the determination of lead and phosphorus will be used as examples because these two elements reflect the unique capabilities of both techniques.
Phosphorus could be satisfactorily determined only by ICP, but great care was required in the choice of wavelength. The determination of lead is simple and straightforward by flame atomic absorption. The determination of lead by ICP was satisfactory but, again, the choice of wavelength was critical to the success of the analysis.
It was found to be most advantageous to use low ultraviolet (UV) wavelengths for the determination of both phosphorus and lead by ICP in order to avoid spectral overlaps by copper and other matrix components. Comparative emission spectral scans are shown for the various phosphorus and lead lines investigated. The severity of spectral interferences is compared for the UV and low UV wavelengths of phosphorus and lead.
This paper presents a comparison of the capabilities of atomic absorption spectroscopy and inductively coupled plasma emission spectroscopy for the analysis of aluminum brasses. Lead and phosphorus will be used as example elements. The points of comparison are the detection limits, the sample preparation requirements, and the interferences encountered.
Replaceable Deep Groundbed Anode Materials
Authors: Tatum JF 
Published: March 2009

The replaceable deep anode groundbed design is described in detail. Each component of the groundbed is shown along with complete details covering the installation thereof, with design factors and other parameters.
The various types of anode materials are described, and configurations of graphite anodes are discussed in detail with particular emphasis on the use of a center-tapped anode to prevent premature anode failure from end effect. Other anode materials are described, such as platinized titanium, platinized niobium, and platinum clad niobium. The use of platinum anode materials are covered in detail along with various anodically passive substrates.
Wire insulations are covered, such as high molecular weight polyethylene, and the dual jacketed insulations involving fluoropolymers along with their performance in downhole environments.
Calcined petroleum coke backfills are presented with information as to their resistivity and the various material specifications available.
The interference characteristics of deep groundbeds versus surface beds are shown in detail. The superiority of the deep groundbed in eliminating anodic interference is described, with data as to causes of cathodic interference.
Program for Steam Purity Monitoring: 1. Instrumentation and Sampling
Authors: Pensenstadler DF , Peterson SH , Bellows JC , Hickam WM 
Published: March 2009

For the past 3 years the Westinghouse Electric Corp. has conducted a major program of instrument selection and development and sample analysis to monitor the steam turbine chemical environment and to determine the source of corrodant species that contribute to turbine blade corrosion.
This paper describes the development and application of a continuous on-line analyzer; a grab sample analysis program, utilizing state-of-the-art ion chromatography, to measure steam impurity concentration at various locations throughout the steam-water cycle; and the combination of these techniques, in the form of a total plant survey, to assess total power plant chemistry.
The significance and usefulness of continuously monitoring parameters such as sodium, dissolved oxygen, conductivities, and chloride is discussed, as are the validity of the sampling procedures, the utility of a nozzle to extract steam, and the strengths and weaknesses of ion chromatographic grab sample analyses. Finally, the implementation of a data acquisition system on the continuous analyzer, to handle the ever-increasing amount of information being generated by seven of these field systems, is reviewed.
Description and Evaluation of a Continuous Sample Water Evaporator
Authors: Elmiger SJ , Mravich NJ , Stauffer CC 
Published: March 2009

Current power industry requirements place increasing emphasis on water and steam purity. Many of the contaminants present in plant systems exist at levels below the detection limits of available analytical methods. Evaporation of large volumes of water in a controlled environment provides a means of increasing the concentration of contaminants to a level that can be readily analyzed by current methodology. Since the continuous sample evaporator described in ASTM Tests for Particulate and Dissolved Matter in Water (D 1888-78) is no longer marketed, an improved version of the evaporator was designed, fabricated, and tested for low-level contaminant recovery.
The new instrument is capable of evaporating solutions from sample bottles or a sample line at rates approaching 500 cm3/h. The samples are concentrated in precleaned platinum dishes. A detailed description of the new evaporators and their operation is discussed.
Performance tests were conducted on both laboratory and field samples to define the limitations of the evaporation process for trace chemical analysis. These analyses included calcium, magnesium, iron, copper, potassium, sodium, chromium, nickel, manganese, zinc, lead, aluminum, silica, sulfate, chloride, phosphate, and nitrate. The laboratory studies showed that the evaporators were capable of chemical species recovery generally within ±20 percent of the absolute amount of synthetic species added. Evaporation and analyses of field samples obtained from operating power plants compared favorably with other concentrating techniques for most species. However, there are certain contaminants which cannot be determined accurately with current evaporation techniques and may require analysis by other available methods.
Experimental Observation of Crack Velocity and Crack Front Shape Effects in Double-Torsion Fracture Mechanics Tests
Authors: Michalske TA , Singh M , Frechette VD 
Published: March 2009

The double-torsion test configuration has been used to obtain crack growth information for a variety of materials. Recently critical reviews have suggested that certain assumptions used in the interpretation of double-torsion data are of questionable validity.
This paper presents experimental data for crack growth in glass specimens loaded in the double-torsion test configuration. The constant displacement rate technique was used to propagate cracks and velocity was measured continuously by superimposing a tuned-frequency sonic signal during cracking. The crack velocity profile as a function of position along the crack front was determined. The crack velocity at the tensile surface was measured as a function of crack length at constant load and the crack front shape was observed for various crack lengths.
Determination of High-Temperature KI-v Data for Si-Al-O-N Ceramics
Authors: Lewis MH , Karunaratne BSB 
Published: March 2009

A “double-torsion” test jig for operation in vacuum or a selected gas atmosphere at temperatures up to 1500°C is described. The jig has been used to determine stress intensity (KI)-crack velocity (v) relationships for single-phase β' Si-Al-O-N ceramics which have been hot-pressed with different “impurity” densification aids and which have received “post-sintering” heat treatments.
The KI-v data have been calculated using three testing procedures; (a) for high crack velocities (10−2 to 10−4 ms−1) from the rate of load relaxation, (b) for intermediate velocities from the “constant displacement rate” technique and, (c) for low velocities (10−6 to 10−10 ms−1) from direct measurements of crack velocity on sequential application of a constant load. A procedure for a “machine-relaxation” correction for technique (a), evaluation of the deviation in the “constant KI” assumption with crack length and the sensitivity to specimen thickness, is described.
The data can be fitted to a relationship of the form v = constant KIn over a wide range of crack velocity with excellent continuity in data obtained from the different techniques and good agreement with isolated values from “notched-beam” tests.
Marked variation in the stress-intensity exponent n which occurs for ceramics with different sintering aids may be correlated with differing susceptibility to subcritical crack growth by means of interlinkage of creep cavities and, in turn, on grain boundary structure. A progressive change in the v-KI relationship with heat treatment in “noncavitating” ceramics is discussed in terms of current theories for diffusive intergranular crack growth.
The consistency of these data, sensitivity to change in grain-boundary structure, and a correlation with creep behavior indicate that double-torsion tests on small ceramic specimens at elevated temperatures may be used with confidence in determining KI-v relationships, either for failure prediction or in distinguishing between different slow-crack growth mechanisms.
Extension of the Compliance and Stress Intensity Formulas for the Single Edge Crack Round Bar in Bending
Authors: Ouchterlony F 
Published: March 2009

The compliance and stress intensity formulas for the solid single edge crack round bar in bending (SECRBB) specimen with a support span to diameter ratio S/D = 3.33 are extended to cover notch depth ratios 0 ≤ a/D &lt; 0.6, an arbitrary Poisson's ratio, and a slight variation in S/D. The work is based on a precise and reliable measurement of the load point displacement on notched rock cores of Ekeberg marble. The measuring method virtually eliminates friction and twisting effects as well as nonlinear contact and crushing phenomena. It yields an accurate value of the Young's modulus.
The experimental results give the extension of the formulas which are used for a thorough fracture mechanics analysis of the SECRBB specimen. The matters considered are the crack growth stability, the secant offset at 2 percent apparent crack growth, and the logarithmic derivative relating the J-integral to work done. Hence a basis is laid for correct linear and nonlinear fracture toughness measurements with the SECRBB specimen.
Measurement of the Hydraulic Conductivity of Fine-Grained Soils
Authors: Olson RE , Daniel DE 
Published: March 2009

The purpose of this paper is to review the state of the art in the measurement of hydraulic conductivity of fine-grained soils. Both field and laboratory tests for saturated and partially saturated soils are considered.
For saturated soils, field tests are to be preferred because they permeate a larger volume of soil, thus taking into account the effects of macrostructure better than laboratory tests. Field tests are generally best performed by using a cylindrical piezometer tip, installed by methods that minimize disturbance, and measuring flow under a constant head. Laboratory tests offer the advantage of economy. Laboratory specimens should be as large as practical and should be oriented to produce flow in the direction of maximum hydraulic conductivity. The permeant should be a fluid similar to that encountered in the field. Without proper experimental technique, the conductivity measured in the laboratory may differ from the field value by several orders of magnitude.
Field tests for unsaturated soils are not well developed and can only be recommended for cases where water will be ponded on the surface of a site. The most versatile laboratory techniques are the instantaneous profile method using tensiometric or psychrometric probes, and the pressure plate outflow method. The best method to use depends on the soil suction expected in the field.
The du Pont F21 149°C (300°F) Accelerated Stability Test
Authors: Henry CP 
Published: March 2009

The du Pont F21 149°C (300°F) Accelerated Stability Test has been used for many years to monitor stability properties of distillate fuels. The test (or variations of it) is the most commonly used in the petroleum industry because, of the many tests available, it is easiest to carry out. A small fuel sample is heated to 149°C (300°F) for 90 min or more, cooled, and filtered; degradation is qualitatively determined by visual or instrumental evaluation of the filter pad—without the need for gravimetric procedures. In our laboratory it is usually the first of several tests to evaluate fuel stability; results guide further work. The test is also used to monitor fuel stability during production, distribution, and storage.
Variations, refinements, applications, and limitations of the test are discussed. Severity is modified by varying the 149°C (300°F) aging period from 90 min to 4½ h. Sensitivity is varied by changing the porosity of the filter paper. Test results are precisely rated by measuring filter pad light reflection. The reproducibility of the test is considered, along with factors which affect results.
Data are presented which show the relationship of test results with actual long-term storage stability of fuels.
Microbial Contamination of Ship Fuels
Authors: Neihof RA , Klemme DE , Patouillet CE , Hannan PJ 
Published: March 2009

A laboratory evaluation has been made of water-soluble biocides which might be effective in controlling microbial contamination in water-compensated fuel storage tanks on naval ships. Higher concentrations of biocides were generally required for control of sulfate-reducing bacteria in steel drums simulating ships' tanks than in test-tube scale assays. At least tenfold higher concentrations were necessary when biocide additions were made after, rather than before, bacterial growth had developed extensively. A mercaptopyridine biocide was effective at the lowest concentration followed by methylene bisthiocyanate and a triazine derivative; an organoboron compound was comparatively ineffective.
Attention has also been given to the possible environmental impact of discharging biocide-treated water. An algal assay has been used to study the loss in toxicity of candidate biocides in seawater solution on exposure to sunlight. The mercaptopyridine biocide was particularly susceptible to photodegradation. Thus it may be possible to control microbial contamination indefinitely in a dark fuel tank with a biocide which photodegrades to nontoxic products when discharged into sunlit surface waters.