bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrostatic Spraying of Oil-Based Agricultural Products
Authors: Simmons HC , Kelly AJ 
Published: December 2008

There is burgeoning interest in the use of oil based, high-persistence media for the low volume application of agricultural chemicals. Although electrostatic atomizers appear to offer the most appropriate means for the effective application of these carriers, it has heretofore been necessary to modify the formulations to permit operation with existing devices. This has entailed altering the intrinsically high resistivity of these fluids (0.1 cu) to the 104 to 106 cu range where existing electrostatic atomizers can function.
A prototype electrostatic atomizer which is capable of spraying unaltered oil-based fluids is described. This device uses direct charge injection to provide unipolarly charged droplet sprays of a wide range of fluids independent of their physical properties. Atomization is purely electrostatic with no auxiliary means such as spinning disks, air blast, or swirl assist being required for droplet formation. A compact device (1 by 2 by 1 in.) is capable of providing flow rates from 0.1 gal/h upwards with constant output charge density. Operation is at about 10 kV and several microamperes for a total electrical input (exclusive of fluid delivery power) of a few tens of milliwatts. This makes the unit compatible with battery operated hand-held as well as power limited mobile applications.
Operating characteristics and droplet size distribution data are presented for a representative test oil. It is shown that droplet size distributions that are considerably more monodisperse than those obtained from conventional atomizers can be readily achieved. This feature, along with the intrinsic “wrap-around” capability of the charged droplets, is a particularly significant attribute for effective application.
Turbine Lubricant Oxidation: Testing, Experience, and Prediction
Authors: Smith AN 
Published: December 2008

Early in the 1970s failure of conventional turbine lubricating oil in modern heavy-duty gas turbines fostered the development of high-temperature mineral oils, the search for appropriate more severe oxidation tests, and efforts to relate the experience to tests and analysis. In parallel with this lubricant effort, bearing and bearing seal developments were undertaken.
The oxidation testing results have evolved into characteristic curves. Operating experience can be related to the heat source temperature. On the basis of the oil characteristic curves and the exposure temperatures, life predictions are made.
In general, the characteristic curves and the operating experience show that the rate of the reaction doubles for every 10°C increase in temperature.
Infrared Spectroscopy as a Tool for Monitoring Oil Degradation
Authors: Coates JP , Setti LC 
Published: December 2008

Oxidative and thermal degradation of lubricating oils are complex processes. While the fundamental chain reaction mechanisms are known, the actual chemistry of a formulation involving several additives still remains a gray area. An understanding of some of the additive interactions and their degradation pathways will ultimately lead to a more scientific approach to formulation optimization for a given application. Current methodology involves laboratory bench tests as a screening mechanism before the more expensive mechanical tests are used for the evaluation of a final lubricant formulation. This is particularly the case for automotive and gas turbine lubricants. The chemistry linking the bench test and the mechanical tests to the oil formulation are rarely considered.
This paper will illustrate how modern infrared spectroscopy can be used to monitor lubricant degradation. Also, it will demonstrate by simple applications, that the technique has the potential of providing much of the information required to follow the chemical reactions that are involved.
Zirconium-Steel Bimetallic Tubing for Improved Sour Gas Corrosion Resistance in Oil and Gas Wells
Authors: Wang CT , Hardwick R 
Published: December 2008

Bimetallic tubing with corrosion resistant liner material has been developed for sour gas well applications where conventional carbon steel tubes have serious corrosion problems.
The present project deals with the tubing consisting of 4130 steel outer wall and zirconium liner. The manufacturing process starts with an assembled billet. To enhance the bonding between layers, either an interlayer copper or an explosive bonding technique may be used for the billet preparation. The billet is hot extruded and then tube reduced to the final size. The final tube can be heat treated and water quenched to meet the requirements of the oil field tubular products. Tests show that the bonding between layers achieved by explosive bonding and extrusion is excellent.
A section of the tube with zirconium liner exposed to a brine solution saturated with hydrogen sulfide (H2S) under a pressure of 1.72 MPa (250 psi) and a temperature of 493 K for 1368 h showed no sign of corrosion attack by the medium. Other corrosion and stress corrosion tests for zirconium also showed excellent results.
Application and Process Metallurgical Aspects of Niobium, Tantalum, and Hafnium
Authors: Krishnan TS , Gupta CK 
Published: December 2008

Among the family of reactive and refractory groups of metals, niobium, tantalum, and hafnium command considerable interest on account of their unique combination of widely differing properties, which makes them ideal or potential candidate materials for a variety of applications in the conventional and frontier areas of technology. Both niobium and tantalum have high melting points and show good resistance to high-temperature oxidation (the oxidation rates for tungsten and molybdenum are about 4 times and 20 times more at any given temperature) and are hence widely used in heat-shields and high-temperature structures. Addition of titanium, cobalt, and nickel further enhances their oxidation resistance, and alloys such as Ta-Ti-Co and Ta-Ti-Ni (commercial production of these alloys has not yet been established), are reported to have been used in advanced ram jet engines. Another important area of application for tantalum and niobium is in the chemical industry, where because of their superior resistance to corrosion attack in several types of chemical media, they are used for making reaction vessels or serve as reactor lining material. Tantalum is perhaps the only metal that can safely be used for ocntaining the highly corrosive molten rare earth metals and their alloys. The metals also find extensive use in the electronics industry for capacitor manufacture owing to their ability to form exceptionally stable surface adherent oxide film. Moreover, niobium finds use in nuclear and magnetics industries because of its attractive nuclear and superconducting properties. The steel industry also needs a significant quantity of niobium in the form of ferro-alloys. Hafnium is another metal that finds use in the nuclear industry, but in a different role, as a control rod material because of its high neutron absorption cross section. The metal also has good potential for use in a jet engine turbine alloy. In the carbide form, all the three metals are widely used in the cutting tool industry.
In the Bhabha Atomic Research Centre, a considerable amount of development work has been carried out on niobium, tantalum, hafnium, and other reactive and refractory metals, and flow sheets have been evolved for the production of metals, some of their carbides, alloys, and ferro-alloys. Based on these processes, indigenous production facilities have also been set up. The paper briefly presents the work that has been carried out on the production technology of the reactive and refractory groups of metals with particular reference to niobium, tantalum, and hafnium.
Ignition of Metals and Alloys by High-Velocity Particles
Authors: Benz FJ , Williams RE , Armstrong D 
Published: December 2008

The ignition of metals and alloys by impacting high-velocity particles in gaseous oxygen was investigated. A convergent/divergent nozzle was used to accelerate the flowing oxygen, which in-turn accelerated the particles to velocities greater than 305 m/s (1000 ft/s). The test sample (target) was placed at the end of the chamber in the flow path.
Aluminum 6061, Type 316 stainless steel, Type 304 stainless steel, and Inconel 718 were ignited with 1600-μm aluminum 2017 particles at elevated temperatures and pressures whereas Monel 400 could not be ignited. The ignition susceptibility of metals and alloys appeared to increase as the inlet pressure, sample temperature, and particle size were increased. Type 304 stainless steel particles required more extreme conditions for ignition of materials than similar sized aluminum particles. The results indicated that ignition and subsequent burning of the particles were required for ignition of the target materials with the possible exception of Aluminum 6061.
Behavior of Fire Spreading Along High-Temperature Mild Steel and Aluminum Cylinders in Oxygen
Authors: Sato J , Hirano T 
Published: December 2008

Effects of the metal temperature and the metal surface condition on the fire spread rate along mild steel and aluminum cylinders have been studied experimentally for wide variations of the oxygen pressure, up to 10 MPa, and the test piece temperature, up to the melting points. Based on the experimental results, the mechanisms by which fire spread is controlled, and the dependence of the fire spread rate on the metal temperature and the metal surface condition have been discussed.
The experimental results show that the fire spread rate does not always increase with the increase of the metal temperature, but the two cases, the increase or the decrease, exist corresponding to the ranges of the oxygen pressure and the metal temperature. The curious dependency of the spread rate on the metal temperature is attributable to the variation of the heat transfer rate from the molten mass to the unburned solid caused by the change of the contour of the boundary surface between the molten mass and the unburned solid metal. The effect of the surface condition on the fire spread rate is small. In this case, the variation of the fire spread rate is mainly attributable not to the variation of the surface reaction rate or the heat transfer rate at the solid metal just above the molten mass, but to the variation of the heat transfer rate from the molten mass to the unburned solid.
Burn Propagation Rates of Metals and Alloys in Gaseous Oxygen
Authors: Benz FJ , Shaw RC , Homa JM 
Published: December 2008

The average burn rates of several metals and alloys were determined at oxygen pressures between 3.45 and 68.91 MPa (500 and 10 000 psig) and ambient temperature. Several materials were tested at elevated sample temperatures. The test materials were fabricated into solid cylindrical rods and mounted vertically in the test chamber. A magnesium igniter was positioned at the bottom end of each test specimen to promote upward burn propagations.
Nickel 200 and copper 102 could not be ignited at all oxygen pressures tested whereas Monel 400 appeared to ignite but quickly self-extinguished. The other materials tested burned the entire length of the test sample. Aluminum 6061 exhibited the fastest burn propagation rate. Inconel 718 burned slower than aluminum but faster than the stainless steels (Types 304 and 316).
Increasing oxygen pressure generally increased the burn propagation rate of the materials. Increasing the ambient temperature of the test specimens for several materials to approximately 850 K (1070°F) had little effect upon the ignition or burn properties of Nickel 200 or Monel 400. Type 316 stainless steel exhibited an increase in its burn propagation rate at this higher temperature.
Case Study of Royal Australian Air Force P3B Orion Aircraft Ground Oxygen Fire Incident
Authors: Grubb JW 
Published: December 2008

In Jan. 1984, the Royal Australian Air Force (RAAF) experienced a ground fire incident that destroyed a six million dollar P3B Orion Aircraft (A9-300). The incident occurred during removal of an onboard oxygen cylinder, one of three that supply the Orion flight crew. Examination of the aircraft's oxygen system revealed that the fire had initiated in an oxygen manifold check valve (MCV) assembly. The primary cause of the incident was a leaking poppet valve, which allowed oxygen stored at 12 MPa (1800 psi) to escape to atmosphere. Deterioration of the silicone rubber seal and galvanic corrosion are believed responsible for the valve failure. Contributory causes to the fire were system contamination and failure to bleed the oxygen system before cylinder disconnection. A thermite reaction involving the aluminum MCV assembly, metal particles, and metal oxide particles was the most likely cause of ignition. RAAF investigations revealed similar contamination throughout the entire fleet of P3B/C Orion aircraft; iron oxide dust was the major contaminant found. Oxygen system filters were also examined, and trials aimed at improving particulate matter filtration are currently being conducted. Extensive cleaning of both aircraft oxygen systems and ground support equipment was also undertaken.
RAAF findings, supported more recently by the U.S. Navy investigations, indicate the need to consider using materials other than silicone rubber in oxygen systems. Further research into the ignition of aluminum and other candidate materials through metal particle impingement in the presence of metal oxides in a high-pressure oxygen environment is also required.
Fracture Analysis of Propane Tank Explosion
Authors: Pearson HS , (Jesse) Dooman RG 
Published: December 2008

A truck-mounted propane tank exploded. The failure occurred through a girth weld, causing a section of the dome to fly from the tank. Initial evaluation of the failed tank showed a crack existed in the girth weld, for several years. The preliminary conclusion of this investigation was that the crack condition was the cause of failure; however, the authors suggested that a fracture mechanics analysis be conducted.
Four compact fracture toughness specimens were fabricated from weld metal in the tank and tested. It was shown that the failure could not have occurred from the existing crack and the tank internal pressure, unless the internal pressure far exceeded the maximum allowable 1.72 MPa (250 psi) pressure.
Further investigation led to the discovery that the relief valve of the tank was corroded so badly that it would not open, thus allowing excessive pressure in the tank. There was evidence that the driver had overfilled the tank. Heat from the sun and from the hot truck tailpipe caused the tank to become liquid full. Then, the pressure exceeded 6.9 MPa (1000 psi), causing the tank to explode. The fracture mechanics analysis thus showed that the explosion was not due only to the existing crack, but also to the stopped-up relief valve and excessive liquid propane in the tank.
Failure Analysis of a Large Wind Tunnel Compressor Blade
Authors: Hampton RW , Nelson HG 
Published: December 2008

A failure analysis was performed to establish the cause and prevent the recurrence of a 2014-T6 aluminum compressor blade failure in a large NASA-Ames Research Center wind tunnel. A metallurgical failure analysis showed that a 0.13 mm (0.005 in.) deep scratch in the shank of the blade had acted as an initiation site for a fatigue crack. The crack subsequently grew by Stage II fatigue across most of the blade's 22.9-cm (9-in.) base transition region before final fracture occurred by unstable crack growth. Extensive fractographic characterization of both the blade and laboratory specimens was performed using a scanning electron microscope. Surface morphology, including fatigue striations, was used to estimate the vibration stress levels, the time to grow the crack, and the magnitude of the local mean stress present.
A structural failure investigation was conducted to determine the resonance vibration condition which made the blade sensitive to a scratch. Studies of the blade natural frequencies were made to determine the mode responsible for the vibrations which grew the crack. The effect of the crack on modal frequency was measured and computed. Tunnel measurements were used to determine the vibration resonance tunnel speed, magnitude, and source. These data were used to compare with the crack growth data from the fractographic studies and to make recommendations to avoid future blade failures.
Fatigue and Fracture Mechanics Analysis of Compression Loaded Aircraft Structure
Authors: Rich DL , Pinckert RE , Christian TF 
Published: December 2008

During depot maintenance of a U.S. Air Force F-15 fighter aircraft, cracks were discovered in the wing upper spar cap at the inboard end of the spar. Since the upper spar cap is a compression member during normal flight, these cracks were an unanticipated phenomenon which required extensive fatigue and fracture mechanics analyses. The tensile stresses resulting from maneuvers and landing were not considered sufficient to cause cracking. Investigation indicated that the local stresses around holes in the compression-loaded spar cap exceeded compression yield, and, upon unloading, residual tensile stresses were induced at the holes. To determine this cause and the exact nature of service loadings, analytical and experimental studies were performed. A large, detailed finite element model was constructed to determine the local loads in the area of fastener holes. A comprehensive program of element specimens subjected to spectrum loading was also conducted to simulate the in-service cracking and determine the effectiveness of various repair configurations. Crack initiation and crack growth characteristics were obtained from the tests.
The number of flight hours to crack initiation at the side of the critical fastener hole was predicted. Crack growth analyses were made using a contact stress model computer program, modified to take into account the residual stresses adjacent to the fastener hole. The results of this crack growth analysis are being used to guide Air Force planning for in-service modifications of aircraft.
Aircraft Structural Maintenance Recommendations Based on Fracture Mechanics Analysis
Authors: Denyer AG 
Published: December 2008

The paper discusses the implementation of the Force Management (FM) phase of the Aircraft Structural Integrity Program (ASIP) for a USAF utility transport/trainer aircraft. The analyses, performed in support of the Force Management tasks, use the principles of linear elastic fracture mechanics with emphasis on subcritical flaw growth. The durability and damage tolerance lives, generated with a crack growth computer program, are the basis for structural maintenance recommendations and inspection intervals presented to the USAF in the Force Structural Maintenance Plan (FSMP).
The case study considered herein shows how the T-39 wing, designed to the fatigue requirements of the late 1950s, performs to the structural criteria of the 1980s as defined by the military specifications MIL-STD-1530 and MIL-A-83444.
The initial FM task was the durability and damage tolerance assessment (DADTA) of the structure based on the current service usage as defined by the loads/environment spectrum survey (L/ESS). An outline of the necessary spectrum development is provided, as is the crack growth analyses leading to estimates of the economic life and structural life enhancement recommendations.
The DADTA was followed by the institution of the individual aircraft tracking (IAT) program, the purpose of which is to compute the rate at which the available structural life of each aircraft is being used and to establish inspection intervals to ensure safety. Tracking is accomplished by compiling flight records, collected by means of pilot logs containing mission information for each flight. The paper will show the economic crack growth procedure used, both to ascertain the accumulated damage based on the flight records and to estimate the remaining structural life.
The conclusion of the paper will discuss the maintenance recommendations and the advantages of using fracture mechanics based aircraft tracking in support of force management.
Role of Fracture Mechanics in Assessing the Effect on Fatigue Life of Design Changes in Welded Fabrications
Authors: Tubby PJ , Wylde JG 
Published: December 2008

Experience has shown that in many instances designers have reacted to service fatigue failures in welded structures in the wrong way, with the result that design changes made have not had the desired effect. It is the intention of the present paper to demonstrate that fracture mechanics techniques, which are now well established, can be used to provide an appreciation of those aspects of a design which are important with respect to the fatigue performance of the structure. This understanding provides an excellent basis for evaluating the benefit of proposed design changes when service problems are encountered.
Analysis is based on stress-intensity solutions derived by two-dimensional linear elastic finite element modelling. Fatigue lives are predicted by integration of the appropriate fatigue crack growth law on the basis that the life of a welded joint is dominated by the propagation of small pre-existing defects.
An important consequence of this feature of their behavior is that the fatigue lives, and hence fatigue strengths, of joints are strongly influenced by factors which affect the rate of crack propagation. Results are given which illustrate that factors such as weld profile, the tensile strength of the parent material, and stress relief by post weld heat treatment have little effect on fatigue strength, although historically designers have often looked to modify one of these in the face of service problems. Other factors such as the detailed design of joints and the reduction of stress concentration factors are shown to be more significant.
It is also demonstrated that even the most fundamental step in the design process, that is, the selection of scantlings, may not have the expected effect on fatigue life since the fatigue strength of a joint may be reduced by increasing the plate thickness.
The Hazard Communication Program at 3M: “You Need to Know”
Authors: Butenhoff JL , McCormick WC 
Published: December 2008

The organizational structure and diversity of 3M has led to the development of a unique system of hazard communication to meet both internal and external needs. 3M is a diversified manufacturer operating in 53 countries with some 6600 kinds of products with annual sales over $8 billion. The large number of raw materials and intermediates used to make these products dictate that 3M has a large responsibility in regard to the Occupational Safety and Health Administration (OSHA) Hazard Communication standard.
A corporate hazard communication committee representing various staff groups has developed a compliance plan. The Medical Department is taking the lead in this effort. The hazard communication programs can be divided into internal programs and external programs. These encompass and provide direction for the major elements of hazard communication. 3M has adopted the phrase “you need to know” as a catchword of the hazard communication program. This paper describes the various aspects of the 3M compliance program.