bluuebunny/crossref_metadata_2025_split huggingface dataset:
Some Recent Observations on the Properties of UHV-Deposited ZrO2
Authors: Raj T , Weaver LD , Tuenge SR , Price JS , Jungling KC 
Published: December 2008

Single-layer ZrO2 coatings were deposited in an ultrahigh vacuum system by two techniques: laser evaporation (utilizing a 100-W, continuous wave, CO2 laser) and electron-beam evaporation. Substrate temperatures were maintained at either 150°C or 250°C with backfill oxygen pressures between 0 and 5×10−5 torr. The coatings were analyzed by Auger Electron Spectroscopy to determine stoichiometry and to provide information on the nature and level of impurities. The refractive indices for the coatings were determined by ellipsometry at 6328 Å. Selected coatings were damage tested at 531 nm.
This report discusses the influence of backfill pressure, substrate temperature and evaporation technique on thin film properties and compares the results obtained by Auger and ellipsometric analyses. Also presented is a comparison between films prepared under high vacuum and ultrahigh vacuum conditions.
Effect of Overcoats on 355-nm Reflectors
Authors: Carniglia CK , Hart TT , Staggs MC 
Published: December 2008

Previous experiments have demonstrated that halfwave overcoats of a low-index coating material are effective in increasing the damage thresholds of dielectric high reflector coatings (HR's) at the wavelengths of 1064 nm and 248 nm. This overcoat layer led to a 50% increase in damage threshold at 1064 nm and to a 100% increase in threshold at 248 nm. This paper presents new results on the effect of halfwave overcoats at an intermediate wavelength: 355 nm.
Results reported at last year's Boulder Damage Symposium indicated that halfwave silica overcoats were detrimental to the damage thresholds of HR's at 355 nm. New results confirm that silica overcoats decrease thresholds and also show that magnesium fluoride overcoats do not improve the thresholds at 355 nm. A series of eight reflectors without overcoats had an average threshold of 2.4 J/sq. cm. The addition of silica overcoats decreased the average threshold by 2%, while magnesium fluoride overcoats decreased the threshold by an average of 7%.
Advanced Fastener Technology for Composite and Metallic Joints
Authors: Speakman ER 
Published: December 2008

The investigations described in this paper were conducted to develop new fasteners and joining methods to reduce the weight and improve the fatigue life of aircraft structures. Three major modes of structural failure—fatigue, fretting, and stress corrosion—are discussed along with recommendations for improvement. Stresscoining was developed to cold-work aircraft structures for fatigue improvement. Fretting fatigue failures have been reduced by using Teflon coatings on fasteners and in faying surfaces of splice joints. Standard stress corrosion test blocks have been designed for evaluation of this failure mode. A crown flush rivet configuration has been developed that does not require head shaving after installation. Qualification tests were performed in compliance with MIL-STD-1312 to obtain Federal Aviation Administration and military approval.
Various new fasteners have been developed for aluminum, carbon-fiber composite, and titanium structures. These fasteners were designed to be “forgiving to the hole” in that they fill and prestress the hole uniformly without being extremely sensitive to hole-preparation tolerances. New low-cost specimens have been designed to provide a basis for screening and comparing fastener tests conducted by fastener manufacturers and aircraft companies. These programs are directed toward creating technology for achieving a more balanced fatigue-resistant aircraft structure.
Fatigue Life Enhancement and High Interference Bushing Installation Using the ForceMate Bushing Installation Technique
Authors: Champoux RL , Landy MA 
Published: December 2008

The patented ForceMate bushing installation process, originally developed by McDonnell Aircraft, involves expansion of a hole and simultaneous installation of an interference fitted bushing. The process provides a significant improvement in the fatigue life of bushed holes in metallic structures and offers reduced bushing installation costs. Fatigue life improvement is attributed both to the creation of residual compressive stresses in the metal surrounding the hole and to the reduction in applied cyclic stress range caused by the interference fitted bushing. Installation is accomplished without loss of corrosion protection because of the initial clearance fit of the bushing in the hole. Installation costs are reduced by the elimination of liquid nitrogen needed for shrinkage of bushings, as well as the significant reduction in installation time and manpower.
This paper describes the ForceMate process in detail. Fatigue lives of simulated aluminum lug geometries with bushings installed using the ForceMate process were compared with lives of lugs with bushings installed using conventional shrink fit methods. Constant amplitude and flight-by-flight spectrum loading were used for cyclic testing. Life improvement factors of greater than 3:1 were shown. Bushing-to-hole interferences were significantly greater than those achievable with traditional shrink-fit installation techniques. The process was demonstrated effectively with bushings manufactured from beryllium-copper, aluminum-nickel-bronze, and steel alloys.
Experimental Characterization of Cracks at Open Holes and in Rounded-End Straight Attachment Lugs
Authors: Nicoletto G 
Published: December 2008

The paper focuses on the application of the frozen-stress photoelastic technique to an assessment of various engineering solutions from the literature for several hole-related crack problems. Single corner, transitioning, and through-the-thickness cracks are examined. Remote tensile loading of a plate containing an open hole and 100% load transfer through a rigid pin in a rounded-end lug is considered.
Experimental evidence demonstrates the presence of stress intensity factor (SIF) gradients for every crack configuration. Good correlation with existing SIF solutions is found for the through-the-thickness configuration in lugs. Less conclusive are the comparisons with engineering estimates for corner cracks emerging from open holes and lug. The transitioning behavior of a part-through crack is also discussed. Finally, modeling aspects of three-dimensional fracture problems are examined.
Additive Package for Used Antifreeze
Authors: Conley JH , Jamison RG 
Published: December 2008

The objective of this study was to develop an additive package that would allow the continued use of MIL-A-46153 antifreeze after its inhibitor system reached a marginal condition. Since Military Specification for Antifreeze, Ethylene Glycol, Inhibited, Heavy-Duty, Single-Package (MIL-A-46153) is a composition specification with a well documented history, a field test kit is used to determine when the antifreeze should be replaced. Eighteen different formulations were screened in ASTM Corrosion Test for Engine Coolants in Glassware (D 1384) with used MIL-A-46153 antifreeze which contained depleted inhibitor ingredients. Two formulations were selected for final testing. Both formulations were similar except that in one sodium silicate was used and in the other, potassium silicate. The formulation with sodium silicate was dropped from further testing when it was discovered that upon sitting for a period of one month the material formed a precipitate. The precipitate does not form in the formulation using potassium silicate.
Results of ASTM D 1384 test and ASTM Method for Simulated Service Corrosion Testing of Engine Coolants (D 2570) show that the formulated additive package used at a 3% concentration in used antifreeze not only gives adequate protection to the six cooling system metals, it is an excellent inhibitor for water. It can also be added to new MIL-A-46153 antifreeze with no deleterious effects. Several military vehicles were selected for a one-year field test and the pH and reserve alkalinity were monitored throughout the test at three-month intervals. The results show that the pH and reserve alkalinity remained at an acceptable level over the one-year period and clearly indicate the coolant was still useable for further service.
It is concluded that the addition of the additive package, Additive, Antifreeze Extender, Liquid Cooling System (MIL-A-53009), to used military antifreeze will allow continued use for a period of time exceeding one year. It has no adverse effect if added to a new fully inhibited antifreeze and is an excellent inhibitor for a water system.
Dynamic Testing of Soldered Joints in Engine Coolants
Authors: Beal RE 
Published: December 2008

A dynamic test for soldered joints in a coolant environment has been developed that allows definitive coolant comparison with respect to soldered joint response in service. The test unit consists of a heated pressure vessel, capable of handling temperatures up to 149°C and pressures up to 0.21 MPa, and twelve specimen jigs. Soldered joints are made under controlled conditions and exposed in coolant under static and dynamic stress rupture conditions. Joint failure is measured on timers that trip upon specimen fracture.
Solder alloys selected for the program were 70Pb-30Sn, 95Pb-5Sn, and 97Pb-2.5Sn-0.5Ag materials. Four commercially available coolants were tested with the above solders at selected loads. A series of tests was also conducted to examine the effect of water used in diluting the coolant. Different commercial coolant and water combinations were found to produce variable degrees of corrosion and joint failure. Solder bloom was found to increase in engine coolant at radiator operating temperatures in the presence of applied stresses.
Observations on Aluminum Water Pump Cavitation Tests
Authors: Oakes BD 
Published: December 2008

Two water pump cavitation tests are currently used by automotive coolant suppliers that wish to sell coolants to automobile manufacturers in the United States. One test is ASTM Test for Cavitation Erosion-Corrosion Characteristics of Aluminum Pumps with Engine Coolants (D 2809). The other is Ford Laboratory Test for Cavitation Erosion-Corrosion Characteristics of Engine Coolants on Aluminum Coolant Pumps (BL 3-1). Details of the test methods are given in the respective ASTM and Ford publications.
Phosphate is confirmed to have a beneficial effect on cavitation. Silicate is shown to be beneficial when used with borate or benzoate, but it can be detrimental to the performance of phosphate. Materials of construction in the test apparatus, copper primarily, can affect the results obtained in the longer term Ford test. Coolants not particularly subject to cavitation appear to fail the test if copper from the test rig piping deposits inside the water pump. Cavitation is not observed with these coolants in the absence of copper. Coolants truly subject to cavitation will show it regardless of the construction materials in the test rig. Finally, it is observed that coolants that will not pass the ASTM pump test at the specified 1:5 concentration will often do so at a 1:2 concentration.
Miniaturized Disk Bend Test Technique Development and Application
Authors: Manahan MP , Browning AE , Argon AS , Harling OK 
Published: December 2008

The objective of miniaturized specimen technology is to enable the characterization of mechanical behavior while using a greatly reduced or minimum volume of material. The significance of this technology is obvious to the nuclear industry where neutron irradiation space is limited and irradiation costs scale with specimen volume. In addition, the substantial advantages resulting from application of this technology in non-nuclear industries are only beginning to be realized.
The initial development of a miniaturized disk bend test (MDBT) for extraction of post-irradiation mechanical behavior information from disk-shaped specimens no larger than transmission electron microscopy samples is described. Central loading with a hemispherically tipped punch is used to measure load/deflection curves to fracture. These load/deflection curves are simulated using finite element analysis. This approach to miniature mechanical property testing is shown to offer the potential for the derivation of uniaxial flow properties.
This paper primarily emphasizes the development of test techniques and procedures; however, results for the determination of uniaxial tensile behavior are presented to demonstrate the validity of the basic methodology. Recommended techniques for specimen design, specimen preparation, experimental design, experimental implementation, and data analysis are presented.
Wire Tensile Testing for Radiation-Hardening Experiments
Authors: Bradley ER , Jones RH 
Published: December 2008

Techniques have been developed for preparing, irradiating, and conducting tensile tests on small-diameter (0.25 to 0.5 mm) wire specimens to determine the effects of high-energy neutron and proton irradiation on mechanical properties. Gage sections were produced electrolytically, and the tensile tests were conducted in an Instron tensile testing machine using a fixture designed to maintain axial alignment and to allow for easy loading of the fragile specimens.
Nickel, niobium, vanadium, and titanium wire specimens were irradiated with T(d,n) neutrons, Be(d,n) neutrons, or 16-MeV protons to fluence levels ranging from 0.2 to 30 × 1021 m−2. The tensile data indicated that yield strength measurements can provide a reliable method of evaluating the hardening produced by high-energy particle irradiations. The precision of the yield strength data ranged from 0.03 to 0.18, depending on radial flux gradients, material grain size, and wire diameter. Greater variations were observed in the elongation and strain-hardening data; these variations were attributed to the tapered gage sections produced by electropolishing. Tensile elongation and work hardening were also strongly dependent on specimen diameter; thus, these properties from small-diameter wire specimens should be used with caution.
Effect of Specimen Size and Material Condition on the Charpy Impact Properties of 9Cr-1Mo-V-Nb Steel
Authors: Corwin WR , Hougland AM 
Published: December 2008

The degradation of fracture resistance of ferritic steels subjected to neutron irradiation can be qualitatively evaluated by examining the shift in the ductile-to-brittle transition temperature and the drop in the upper-shelf energy as determined in the Charpy impact test. That is an empirical test, however, and its usefulness is derived primarily from either correlation to more quantitative measures of fracture toughness or comparison with other Charpy test results for different materials or conditions of interest. Any departures from the standard testing procedures, including specimen dimensions, will yield results which will vary in some degree from those of a standard test.
In examining the effects of neutron irradiation on the fracture resistance of the high-chromium ferritic steels which are candidates for the first wall of magnetic fusion reactors, it is necessary to severely limit the size of the test specimens to be fit within high-flux test reactors. Impact specimens with cross sections as small as ⅓ by ⅓ cm are employed. To evaluate the effectiveness of small specimens in measuring the relative shift in transition temperature and drop in upper-shelf energy, compared with a standard Charpy specimen, a study of the impact properties of 9Cr-1Mo-V-Nb steel in both the normalized and tempered and the quenched-only condition was conducted. Full-size and various subsize Charpy V-notch specimens of two orientations were examined in both material conditions.
Comparing the test results of the tempered with the embrittled 9-Cr-1Mo-V-Nb steel showed that larger transition temperature shifts and smaller fractional drops of upper shelf were measured with the small specimens relative to the standard-size specimens. Attempts were made to improve the correspondence of data by fracture area and volume normalization. No improvement in the shift or shelf drop was obtained. However, a fair agreement for the higher energy tests of absolute energy was obtained with fracture volume normalization.
Microstructure of Supercooled Submicrometre Aluminum-Copper Alloy Powder
Authors: Ridder SD , Shechtman D 
Published: December 2008

Various Al-Cu alloy powder particles were produced by electrohydrodynamic atomization. The particles produced by this process range in size from 3 nm to 2 μm. The microstructure of the submicrometre particles is shown, and a discussion of their cooling rates and solidification history is presented.
The alloys produced included various compositions of aluminum and copper. Extended solid solubility was observed in all the alloys and was dependent on the particle size and concentration. The particles produced from alloy concentrations beyond the equilibrium solubility limit which exhibit segregation-free microstructure probably solidified after undercooling sufficiently to produce the interfacial temperatures and velocities necessary to suppress segregated growth. These aspects of solidification are discussed and estimates of the cooling rates and bulk undercoolings achieved are given. Some of the particles show a transition from partitionless solidification to a segregated, cellular solidification.
Influence of Hydrogen on the Ductility of 7091 and 7090 PM Aluminum Alloys
Authors: Meunier J 
Published: December 2008

Two high-strength aluminum alloys, X7091 and X7090, were produced by powder metallurgy (PM) processing, which included gas (air or helium) atomization, cold compaction, hot vacuum degassing, hot compaction, and extrusion. The products were then solution heat treated, water quenched, stress relieved, and aged as follows: Alloy X7091 was aged for 24 h at 120°C plus 4 h at 163°C and Alloy X7090 for 24 h at 120°C plus 1 h at 163°C. The mechanical properties in the longitudinal and transverse directions and the hydrogen (H2) content were then measured.
The author observed that the H2 content of the different products varies from 1 ppm to more than 10 ppm as a function of the quality of the degassing process and that, though the mechanical properties (yield strength, ultimate tensile strength, and elongation) are not affected in the longitudinal direction, the elongation in the transverse direction can decrease from 10% for an alloy with low H2 content to 0% for an alloy with high H2 content.
It is, however, difficult to correlate the hydrogen content with ductility: a high-H2 alloy can have good ductility when highly oxidized. This phenomenon can be explained by a beneficial hydrogen getter effect by the oxide. It seems, then, that the best way to characterize the soundness of the PM aluminum alloys is by their hydrogen and oxygen contents.
Thermomechanical Treatment of 2124 PM Aluminum Alloys with Low and High Dispersoid Levels
Authors: Sarkar B , Barry Lisagor W 
Published: December 2008

The effects of thermomechanical treatment (TMT) on the mechanical properties and metallurgical structure of 2124 powder metallurgy (PM) aluminum alloys prepared from rapidly solidified powders were investigated. The alloys were prepared by using a standard canning/vacuum degassing/hot consolidation/extrusion sequence. Two compositions, with manganese contents of 0.5 and 1.5%, were investigated to examine the effects of low and high dispersoid levels.
The results indicate that significant improvements in strength can be accomplished through TMT for this PM alloy system with little loss in toughness. The increase in strength observed is attributed to the presence of much finer, more homogeneous S′ precipitation than that observed without TMT. Rolling deformation at room temperature resulted in some tendency for nonuniform (planar) deformation and resulted in slightly lower notch strength values. The lower notch strengths observed in the higher manganese composition were attributed to the coarser, more dense dispersoids observed in this material.
Use of Detrended Correspondence Analysis in Evaluating Factors Controlling Species Composition of Periphyton
Authors: Leland HV , Carter JL 
Published: December 2008

Detrended correspondence analysis (DCA) was evaluated for its usefulness in elucidating relationships among samples and among species of periphyton in an oligotrophic stream, and for its effectiveness in displaying major gradients where an experimental gradient (copper) affecting species composition was imposed. It was highly sensitive to differences among samples and consistently provided ecologically meaningful species ordinations.
Gradients related to seasonality of taxa and year-to-year differences in population densities were evident in DCA ordinations if data for all sampling dates were included, and these gradients complicated interpretation of the copper gradient. Clear discontinuities between samples in control and copper-treated stream sections existed only if data for each sampling date were ordinated separately. Prior to copper exposure, stage of succession of the community was the major gradient displayed in species ordinations. During periods of exposure, sensitivity of taxa to copper was the primary factor controlling the spatial distribution of periphyton. Stage of succession was a secondary gradient during exposure and complicated interpretation of the copper gradient after a major disturbance event (flooding).
Consolidation in the Intergranular Viscosity of Highly Compressible Soils
Authors: Zeevaert L 
Published: December 2008

The author has been interested for several decades in finding better correlations, from the practical engineering point of view, between theory and the phenomenological behavior of highly compressible soils as observed in oedometer tests and in the field.
The author has developed a theory on secondary compression or intergranular viscosity in the consolidation process as he has gotten more experience in the field. The theory is based on two rheological models: the Terzaghi model and the Z-unit developed by the author. The theory has been revised, and currently offers good correlations in the interpretation of the phenomenon observed in practice.
The theory calls for the ability to develop fitting methods to obtain the parameters necessary for the formulae. Two fitting methods are used to cover the consolidation curves observed in the tests performed in the oedometer with undisturbed specimens and in the range of the recompression close to the critical stress. The method proposed also may be used after the critical stress zone has been passed and the soil structure is stabilized at a new stress level. Several examples of fitting calculations are given in the paper to acquaint the reader with the method for practical use.
The author discusses problems with the oedometer conventional test, and ends with recommendations and an analysis of the material presented.
Consolidation of Natural Clays and Laboratory Testing
Authors: Kabbaj M , Oka F , Leroueil S , Tavenas F 
Published: December 2008

A numerical model has been developed, making use of a strain-rate-dependent compressibility law and a permeability-void ratio law, both experimentally established. The numerical program is used to simulate the behavior of clay specimens submitted to oedometric tests (MSL, CGT, creep, etc.). The following conclusions are drawn:
1. The effective stress-strain clay behavior depends on the type of test carried out. In particular, the preconsolidation pressure value varies from one test to another.
2. Each element throughout the specimen follows a specific stress-strain relation depending on its strain rate history. Moreover, the oedometric curve, as usually interpreted from a multiple-stage loading (MSL) test, does not agree with any of these relations, not even with the average curve followed by the whole specimen.
3. The pore pressure isochrones maintain the same shape during controlled-gradient (CGT) or creep tests, in particular when the effective stresses correspond to the preconsolidation pressure.