bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computor Assessment of Fast Neutron Flux
Authors: Gardner L. B. , Shoemaker N. F.
Published: September 2009

Techniques of fast neutron assessment will be described which are applicable when no assumption is made as to the flux distribution; as for example, assuming a fission spectrum. These techniques have been utilized to program the IBM 1620 Digital Computer. The cross section data as a function of energy and a first estimate of flux distribution is utilized in this program, as opposed to the customary technique of utilizing effective cross sections based upon a particularly assumed flux distribution. The computer program is iterative, taking the flux distribution calculated in each pass through the analysis and comparing it to the distribution assumed at the beginning of the calculations for that particular pass. If the differences are not sufficiently small, the resultant calculation of flux distribution is taken as a new estimate of the flux distribution and the calculations repeated for another pass. The output of the program is an estimate of the differential neutron flux spectrum measured in neutrons/cm2/sec/ev/watt. The energy range of the response of each foil selected for the experimental phase of this work is determined by the computer program based upon that foil’s cross section with respect to energy and the estimated flux distribution. The first few percent of the foil’s response, both at the lower and higher energy portions, are discarded; thus, for each successive iteration the total energy range of the foil’s response is truncated. This is done for three successive iterations. Experience has shown that the computer program converges adequately after a few iterations.
Comments on Aircraft Fluid Fire Hazard Assessment
Authors: McCord R. S.
Published: September 2009

Tests for assessing the fire hazard from hydraulic fluids, coolants and lubricants in aircraft have been evaluated in light of the new hot wing compartment condition to be encountered in future supersonic transport aircraft (SST's). Existing flammability tests for subsonic aircraft report inception of visible flame while SST's require tests reporting excessive temperature, or pressure rise as the evidence of flammability. The large number of environment variables affecting flammability prevent certain extrapolation of a fluid's hazard rating from a test procedure to actual conditions of use. Flammability is thought to be more a condition of environment than a material property.
Assessment of the Flammability of Aircraft Fluids
Authors: Macdonald J. A.
Published: September 2009

The methods adopted for assessing the fire resistance of aircraft fluids have been critically reviewed. Most attention has been devoted to an examination of methods of assessing the likelihood of spontaneous ignition of fluids under the most severe conditions that may be encountered in flight. The present closed vessel and hot manifold tests are inadequate and may be misleading. Some other tests, for example the wick, spark ignition of spray, and CAA flammability reference scale, are criticized as being too narrow in their scope.

It is suggested that adequate basic information on the flammability of fluids would be obtained by improved versions of two simple tests:

1. Flash point (lower and upper).

2. Minimum spontaneous ignition temperature in a larger isothermal enclosed apparatus.

Where the application involves ignition on the outside of a hot body in cooler surroundings, the effects of environmental factors are so strong that each case should be treated individually, though some guidance can be provided by tests on a 6 in. hot pipe or flat plate.
Industrial and ASTM Fluid Fire-Test Programs
Authors: Early C. L. , Hatton R. E.
Published: September 2009

As the use of fire-resistant hydraulic fluids has increased over the past 15 to 20 years, so has the number and types of tests used for assessing fire resistance. Organizations which have studied this nebulous fluid property include ASTM, Factory Mutual, SAE, Underwriters' Laboratories, U.S. Bureau of Mines, U.S. Military groups, and several corporations. Tests developed by these groups fall into distinct classes; for example, pressure-spray, molten metal, hot manifold, wick type, etc., but many variations exist among specific procedures of a given test type.

A special group — Section VI of Technical Division N of ASTM Committee D-2 — was established 10 years ago to study fire resistance of fluids, but its progress has been slow. A major problem confronting industry today is the lack of test standardization and interpretation of test results to adequately measure fire resistance of fluids. Cooperative effort is recommended.
Miniaturized Tests for Fire Resistance of Hydraulic Fluids
Authors: Johnson D. E. , Furby N. W.
Published: September 2009

Some of the conventional tests for assessing the fire resistance of hydraulic fluids use relatively large amounts of fluid in relationship to quantities available from exploratory research programs. To alleviate this problem, four miniaturized tests were devised for evaluating fire resistance of aerospace fluids. These were intended to simulate the following normal-size tests: (1) flash point (Cleveland open cup), (2) hot manifold, (3) low pressure spray, and (4) high pressure spray. The microflash apparatus uses a spark plug and a heated aluminum cylinder. Three drops of fluid are applied at each temperature of the test. Results were somewhat higher than for full-scale equipment. Low pressure spray test employs an airless spray gun (rotating disk) with reservoir modified to hold a small volume of fluid. In the high pressure spray apparatus, gas pressure forces fluid from a small orifice in stainless steel tubing, and only 20 ml of fluid is used in each determination. The small-scale hot manifold test uses a 1/2-in. diameter stainless steel heater. These miniaturized tests require a total of 40-ml of fluid, as compared to about 2500 required for the corresponding full-scale tests. The small units are easy to operate, and repeatability is good.
Operating Experience with Trucks and Automobiles Fueled with Propane
Authors: Carson Clyde
Published: September 2009

Over 100 trucks and automobiles equipped with dual propane-gasoline fuel systems are used by Southern Union Gas Company in New Mexico. Use of propane has resulted in longer useful vehicle life and a net reduction in cost of approximately one cent per mile, along with a significant reduction of air pollution.
LP-Gas Fuel Systems—Design and Performance
Authors: Coon C. W. , Abbott R. G.
Published: September 2009

Engine test information was combined with physical carburetor measurements to produce correlations which can be used for design purposes. The correlations were phrased in terms of dimensionless groups of variables. A method, based on the correlations, of extending the versatilit of engine test results was proposed.

In addition, preliminary results were presented for tests conducted with a rotary engine operating on LP-Gas.
Light Duty Fleet Experience with LP-Gas
Authors: Kramer Maury , Bintz L. J. , Tappenden T. A.
Published: September 2009

The Automobile Club is conducting an extensive testing program to determine the suitability of LP-Gas as a substitute motor fuel to help reduce emission levels. In addition to the emissions characteristics of converted vehicles the Club is concerned with maintenance, driveability, safety, and costs. The following conclusions were reached: (1) Operations of motor vehicles using LP-Gas is practical in a fleet operation. (2) Emissions levels are significantly lower for vehicles operating on LP-Gas than they are for similar vehicles in similar service operating on gasoline. (3) Maintenance requirements for LP-Gas powered vehicles are lower than those of similar vehicles in similar service. (4) Available horsepower of LP-Gas powered vehicles is reduced slightly, but this does not affect the driveability significantly. (5) The conversion to LP-Gas is cost effective and will pay out well within the life expectancy of the vehicle. It is practical to move conversion kits from vehicles which are being retired to replacement units. (6) The fuel is safe and easy to handle.
Coal and Coke: Occurrence, Testing and Utilization
Authors: Fieldner A. C. , Selvig W. A.
Published: September 2009

Coal was first discovered in North America on Cape Breton Island, Nova Scotia, and was described in 1672. In the United States, the earliest recorded discovery of coal is that of Louis Joliet and Father Marquette in 1673 on the Illinois River between the present sites of Utica and Ottawa, Ill. The first coal mine opened was near Richmond, Va., about 1730. Mines in that vicinity were operating commercially by 1750, and by 1789 shipments were being made to Philadelphia, New York, and Boston, where coal imported from Scotland, England, and Nova Scotia had been used as early as 1738.
Manufactured Gas
Authors: Dashiell P. T. , Trembly F. H.
Published: September 2009

While we are this year in Philadelphia celebrating the centenary of gas service in the city, the history of gas can be traced back about 1000 yr., for the Chinese used natural gas as far back as 900 A. D. It was not until 1792 that gas was actually manufactured and used. This occurred in England. In that year William Murdock, a Scotch engineer, distilled coal in a retort, produced gas, and lighted his home with it. Therefore, for the first time the “spirit” of coal that had puzzled the early physicists of medieval times and had been called by them the ghost of coal (Van Helmont, 1609, Dutch physicist, first used the term geist, “ghost”) was put to man's use. The word “gas” is probably a corruption of the German “geist,” meaning spirit or ghost, which was the name given by the alchemists to the volatile portion of coal.
Liquefied Petroleum Gas
Authors: Bateman W. H.
Published: September 2009

The liquefied petroleum gas industry received its initial start from Herman Blau, who developed blaugas in Germany, some twenty-eight years ago. This gas was originally used for lighting, although more recently it has been used for cooking, heating and as fuel for the Graf Zeppelin.
The Economic Relationship Between Design and Acceptance Specifications
Authors: Grant E. L.
Published: September 2009

Few specified tolerance limits for qualities of manufactured product are enforceable in the sense that 100 per cent conformity to them can be insured. The establishment of a design specification should therefore be viewed as a problem in economy that cannot be solved without consideration of the acceptance specification that is to be used in its enforcement. The solution of this problem in economy requires the point of view of statistical method and makes use of the tools of statistical quality control.
Precision and Accuracy of Test Methods
Authors: Wernimont G.
Published: September 2009

All A.S.T.M. committees make use of data which have been obtained by the use of physical or chemical test methods. It is important to know something about the reliability, the precision, and the accuracy of these methods.

If a test method gives results which are erratic and unpredictable, it cannot be considered to be reliable. The reliability of a test method can be studied by planning a series of determinations so that the individual results can be grouped in some logical way. The variability within these small groups can then be used as a yardstick to determine whether all assignable causes of variation have been properly controlled. It is a waste of time to try to evaluate the precision and accuracy of a test method until it has been shown that the method is reliable.

The precision of a test method is a measure of how variable the method is when used under well-controlled conditions. It is convenient to express precision by means of the standard deviation of individual measurements. The average range within small groups of test measurements can be used to estimate the standard deviation.

A test method can be considered accurate when it will give measurements on a sample of test material which do not differ from the known value by more than can be explained by the random variations of the method.

The results of properly designed experiments to establish the reliability of a test method can be profitably studied by the use of simple statistical control charts. Test method precision and accuracy can also be evaluated with the help of this technique.
Influence of Boron on Cast Cobalt-Base S-816 Alloy
Authors: Blatz W. E. , Reynolds E. E. , Dyrkacz W. W.
Published: September 2009

Cast cobalt-base alloys with stress-rupture properties at 1650 F equivalent to those of S-816 alloy at 1500 F were developed in the investigation described. This outstanding strengthening effect resulted from additions of boron, the influence of which was studied extensively. Optimum rupture strengths plus good rupture ductility are obtained with approximately 1 per cent boron. The boron range is wide enough to permit commercial production. These alloys also possess excellent casting characteristics.
Chromium-Nickel Alloys for High-Temperature Applications
Authors: Bucklin Albert G. , Grant Nicholas J.
Published: September 2009

Chromium-nickel alloys containing 35 to 70 per cent chromium with additions of iron, molybdenum, and columbium have been precision cast and tested in stress-rupture at 1600 to 1800 F. Results surpassing many commercial alloys have been obtained, especially with alloys containing 40 to 45 per cent chromium, 2 to 10 per cent iron, 2 per cent molybdenum, and 2 per cent columbium. Higher chromium alloys exhibit high hardenability which may make possible high-temperature bearing applications. Forging of the 40 to 50 per cent chromium alloys is difficult, but possible, and should improve through vacuum melting.
Effect of Rare Earth Additions on the High-Temperature Properties of a Cobalt-Base Alloy
Authors: Breen J. E. , Lane J. R.
Published: September 2009

Improvements in the high-temperature mechanical properties of a typical cobalt-base alloy were achieved by the addition of rare earths as misch metal. Three alloys of the same base composition but with 0 to 2 per cent rare earth added were cast from a split heat. Stress-rupture tests were run at 1500, 1600, and 1700 F.

The high-temperature strength as well as ductility were increased in both as-cast and aged material at all temperatures, with the greatest benefit occurring at 1500 F. No improvements in room temperature tensile properties were noted.
Creep, Rupture, and Notch Sensitivity Properties of S-816 Alloy up To 1650 F Under Fatigue and Static Stress
Authors: Vitovec F. , Lazan B. J.
Published: September 2009

Fatigue, rupture, and creep data obtained under various combinations of mean and alternating stress are presented for S-816 alloy at temperatures of 75, 1350, 1500, and 1650 F. Tests were performed under axial stress on unnotched specimens and specimens having theoretical stress concentration factors of 2.4 and 3.4. The data are presented as S-N curves and stress range diagrams to show the effect of specimen notch, temperature, ratio of alternating-to-mean stress, and stress magnitude on the fatigue and creep properties. The role of both creep and fatigue as design factors and the relation of notch sensitivity to loading conditions are discussed with particular reference to temperature and ratio of alternating-to-mean stress.
Titanium-Carbide-Base Cermets for High-Temperature Service
Authors: Pfaffinger K. , Blumenthal H. , Glaser F. W.
Published: September 2009

The development of titanium-carbide-base cermets containing 25 to 65 per cent of nickel-chromium or nickel-cobalt-chromium binder is described. Production procedures and physical properties of these materials at room and at elevated temperatures are given. The applicability for the production of parts to be used in the temperature range of 1700 to 1800 F is discussed.
Titanium-Carbide Products Produced by the Infiltration Technique
Authors: Skolnick Leonard P. , Goetzel Claus G.
Published: September 2009

Work conducted on a metal-bonded titanium-carbide material made by the infiltration technique shows impact strength superior to the conventional cemented titanium-carbide materials. A fine isolated carbide phase seems to provide improved toughness, and the infiltration process appears capable of producing such a structure. Stress-rupture properties compare quite favorably with those of Alloy X-40. At 1800 F at a stress of 15,000 psi, the life of some of the infiltrated titanium-carbide grades is over 1000 times that of cast X-40.

Processwise, the infiltration technique permits the use of low pressures for compacting the powders, making possible direct pressing of complex shapes. The infiltration per se permits the production of void free bodies of remarkably true shape and close dimensional tolerances, and in many aspects is strikingly similar to precision casting.

Infiltrated titanium-carbide products may very well prove to be excellent high-temperature materials for use above 1600 F.
High-Temperature Properties of Molybdenum-Rich Alloy Compositions Made by Powder Metallurgy Methods
Authors: Bruckart W. L. , Jaffee R. I.
Published: September 2009

Molybdenum compositions made by powder metallurgy methods with metallic and oxide additions were studied. The effects of these additions on creep-rupture properties and on resistance to recrystallization are described. Results showed that nonmetallic dispersions provided greater increases in rupture time than solid solution additions. Outstanding among the nonmetallics were ZrO2 and TiO2. Silicon was the outstanding metallic alloying addition. At 1800 F, some of the oxide additions increased the rupture strength of molybdenum almost fourfold. The best metallic additions were considerably less effective than the best oxide additions.
Thermal Fatigue Testing of Sheet Metal
Authors: Lardge H. E.
Published: September 2009

The paper is concerned with the thermal fatigue testing of sheet metal carried out over a number of years. The test program was first embarked upon when cracks, which were not thought to be due entirely to mechanical fatigue, were found at the edges of holes in sheet-metal flame tubes.

A thermal fatigue test was devised based on heating a test specimen with a central hole to 1650 F and then cooling it rapidly in a blast of cold air. The thermal cycle was based on the temperature curve taken on a flame tube on an engine during accelerating and decelerating conditions.

The early work was concerned with Nimonic 75—a nickel-chromium alloy used for flame tubes on most British engines—and showed the relationship between increasing thickness of sheet and thermal fatigue life and also the temperature-life relationship of this material. The program was then widened to include other nickel-base alloys; austenitic and duplex stainless steels; mild and low-alloy steels (protected from corrosion); and laminated materials.
Thermal Shock Testing of High-Temperature Metallic Materials
Authors: Hunter Thomas A.
Published: September 2009

A program of investigation has been undertaken to evaluate the resistance of various materials to thermal shock. A preliminary analysis of thermalshock damage has been carried out on a theoretical basis. The results of this theoretical work indicate that the scope of the problem is so wide that purely analytical methods must be supplemented by experimental data.

An experimental program has, therefore, been set up, and fifteen selected materials have been tested. These include types 304, 310, and 347 stainless steels, K151A and K152B cermets, N-155, cast and wrought S-816, Waspalloy, Hastelloy C, Inconel, Nimonic 80-A, M-252, cast HS-21, and Battellalloy. Suitable apparatus has been constructed which gives reasonable reproducibility of results. A standard specimen shape has been devised after considerable experimentation. Excursions into the subjects of previous specimen history, mechanical fatigue, and thermal wiggling have been made.

Comparative evaluations for the fifteen materials have been made for temperatures between 1600 F and 2000 F.
The Development of Zirconium-Rich Protective Coatings and Brazing Materials for Heat-Resisting Alloys
Authors: Blainey Alan
Published: September 2009

Heat-resisting alloys of nickel (the Nimonics) and iron (chromium-nickel steels) are finding increasing application for the construction of dies used for the hot forming of metals and metal powders. Although these alloys are strong and tough at temperatures in the range of 1350 to 1750 F, they are liable to suffer from surface erosion, particularly in extrusion, for example, where the rate of flow of the deforming metal is considerable. This surface erosion is caused mainly by two effects: (1) partial welding of the deforming metal, followed by tearing away of portions of the surface of the die material, and (2) the formation of relatively low melting point eutectics (from constituents of the deforming metal and the die material) which are continuously squeezed out of the reaction zone due to the high pressure. Such effects can be reduced by preforming a suitable adherent oxide film on the dies (for example, chromium oxide on Nimonic alloys) and by the use of die lubricants such as graphite, but these methods are not infallible, and the films formed are very thin and readily abraded. It was considered that better protection would be afforded by an adherent coating of suitable alloys, high melting point eutectics, or intermetallic compounds, formed with, and on the surface of, the die material. Preferably such a coating should be formed by a relatively simple technique, such as diffusion of a mechanically applied coating into the surface of the base metal.
Creep and Rupture Test Pyrometry
Authors: Wilks Charles R.
Published: September 2009

The importance of accurate temperature measurements and precise temperature control in creep and rupture testing is generally recognized. Both are urgently stressed in the pertinent ASTM recommended practices which emphasize that the recommended temperature limits are not intended to relieve the testing laboratory of the need to make every effort to control within much narrower limits and, in particular, to hold short-term temperature fluctuations to a minimum.
An Apparatus and Method of Vane Shear Testing of Soils
Authors: Gibbs Harold J.
Published: September 2009

A vane tester for determining the in-place shearing resistance of saturated clayey soils has been devised with the principal features of a controlled rate of testing and a simplified, accurate method of stress measurement. The instrument applies a balanced-moment torsional force to the vanes and permits measurements of stresses which are not affected by friction in the loading mechanism. Also, the instrument is sturdily constructed for field use and is adapted to standard drilling and exploration methods. Data obtained during deep foundation investigations in soft soils are also presented.
Deep Vane Tests in Gulf of Mexico
Authors: Fenske Carl W.
Published: September 2009

A deep vane boring was made at a location in the Gulf of Mexico using a new vane borer. A description of the vane borer and an evaluation of its operation are given. In-place shear strengths measured with the vane to a depth of 241 ft below the water surface are compared with shear strengths from laboratory tests on undisturbed samples.
Progress on Metalfilm Strain Gages
Authors: Bean William T.
Published: September 2009

The Metalfilm high-temperature strain gage (Fig. 1) was designed to achieve maximum conformability to irregular surfaces. Lateral stability of the unmounted grid was achieved by employing unique extensions of the grid and by making the width of each element approximately one hundred times its thickness. Thus, the mass was extremely small and the surface-to-mass ratio high. Superior bonding strength was achieved. (These gages have been operated at 100,000 g.) An effort was made to reduce drastically the stress concentrations common to other strain gages. Removing the Metalfilm gage from its temporary backing is simple. Cementing it in place is easy. Suitable grids may be cemented to other backing materials to form premounted gages. The side bars provide mechanical protection for the grid. Lead wire ribbons, approximately ten times the thickness of the gage, connect the strain gage tabs with the lead wires by spot welding. Two basic grid configurations are available: (1) one whose width is twice its length, and (2) one whose width is equal to its length. Six effective lengths are standard: 116, 18, 316, 14, 38 and 12 in.
Advances in Static and Dynamic High Temperature Strain Gage Research
Authors: Kemp Richard H.
Published: September 2009

A static high-temperature strain gage using Karma wire and either Quigley 1925 or Brimor U529 ceramics has been found to be satisfactory for measuring static strains at temperatures up to 800 F. The gage can be used in situations involving variable temperatures as well as a constant temperature during the loading and unloading cycles. For dynamic strain measurements at temperatures up to 1500 F, a coating material developed by the U. S. Army Corps of Engineers at the Fort Belvoir Laboratories has been found to be superior to other cements tested. A high degree of success has been obtained with this material in mounting gages on turbine blades and combustor liners of turbojet engines.
Temperature Compensation of High-Temperature Strain Gages
Authors: Gray Edward I. , Grossman Arthur , Rubin Melvin R.
Published: September 2009

Recent investigations on the thermal behavior of aircraft structures undertaken for the Wright Air Development Center by Allied Research Associates, Inc., included a series of laboratory tests on the Baldwin-Lima-Hamilton Nichrome V foil high-temperature strain gage, type HFN-3. The test results indicated that biaxial strain conditions make it impractical, for high-intensity transient thermal loading of aircraft structures, to attempt compensation for the effects of temperature on strain gage readings by the use of a temperature-compensating dummy gage. Therefore, a temperature-compensation calibration curve was prepared for the Nichrome V foil gage. For this purpose, thermal strain data were compiled with this gage bonded to a free aluminum plate. Temperature-compensated data taken from similar gages mounted on a simple cantilever aluminum strip subjected to combined mechanical and thermal inputs were then compared with the strain measurements obtained by the free-plate method with favorable results. Sufficient data were obtained to permit the construction of a calibration curve for application of this gage bonded to other metals as well. The results of these tests are presented graphically accompanied by a brief description of the experimental procedure.
Laboratory Evaluation of Nichrome-Foil Strain Gage Installations Up to 1200 F
Authors: Forlifer William R.
Published: September 2009

An experimental program was conducted recently at The Martin Co. to explore the problem areas associated with strain measurement up to 1200 F. The areas included bonding techniques, temperature compensation methods, effects of temperature cycling and sensitivity variations. Tests were conducted on cantilever stainless steel specimens.

The results indicate that temperature cycling has a significant effect on the strain-gage reading under no-load conditions. Possible errors are presented both for the temperature effect on the no-load strain reading and for the variation of sensitivity with temperature.
Optical Strain Gages for Use at Elevated Temperatures
Authors: Howerton H. K.
Published: September 2009

The optical strain gages described in this paper comprise three types of commercially available optical strain gages suitable for operation at 500, 1000, and 1500 F. Each type is used in conjunction with the Tuckerman autocollimator. They have been used for determining mechanical properties of material at elevated temperature and for evaluating the performance of remote reading strain gages at high temperatures.
A Facility for the Evaluation of Resistance Strain Gages at Elevated Temperatures
Authors: Bloss R. L.
Published: September 2009

Because of the urgent need for making strain measurements under elevated temperature conditions, a number of “high-temperature” strain gages have recently become available. Although most of the companies producing these gages provide some performance information, potential users are in need of much more complete information in order to choose a gage suitable for their needs and to interpret test results obtained with it. Such information will also assist in the development of better gages. A facility which is being established at the National Bureau of Standards for the comprehensive evaluation of these gages is described and some typical results of the evaluation tests are shown.
Evaluation of Several Gage Configurations Fabricated with Armour Alloy “D”
Authors: Shrager Jack J.
Published: September 2009

Early in its investigation of a strain gage for use in measuring static strains at temperatures up to 1600 F, the Aeronautical Structures Laboratory found that gage performance was limited by the temperature characteristics of the commercial alloys employed as the sensing element. Accordingly, a program was sponsored at the Armour Research Foundation for the development of a superior strain-sensing alloy. Some of the results of this program are reported in this symposium by workers at the Armour Research Foundation. The most promising of the alloys developed appeared to be alloy D which has a nominal composition of 70 per cent iron, 20 per cent chromium, and 10 per cent aluminum.
Ceramic Coatings for Experimental Stress Analysis
Authors: Stern F. B.
Published: September 2009

This paper presents a brief history and development of resin-base brittle coatings for experimental stress analysis. These coatings have been in use for a number of years but are limited in operation to temperatures up to approximately 100 F.

A new series of ceramic-based materials has been developed which will operate from approximately —50 to 600 F in a sensitivity range of 200 to 1800 microinches, depending on the coefficient of expansion of the steel on which the coating is applied. These ceramic brittle coatings permit experimental stress analysis on steel parts up to 600 F.

Neither the presence of oil and high humidity, nor slow application of loads affect the test results. Dynamic tests may be conducted with the ceramic coatings in areas where abrasion by air or dust would prevent use of the resin-base materials. Tests may be conducted out of doors for indefinite time intervals. Thermal strains can now be measured by these brittle coatings.

Some illustrations are given of the use of the ceramic coatings to measure stresses on a gas turbine rotor.
Foil Gages for High-Temperature Applications
Authors: Hines Frank F.
Published: September 2009

Many reports on the evaluation of resistance-type high-temperature strain gages by the National Bureau of Standards. U. S. Naval Air Material Center, and others, have demonstrated that considerable variation in performance may be expected from presumably identical high-temperature straingage installations. The Baldwin-Lima-Hamilton Corp. experienced this to be true even when careful precautions are taken to insure that the foil- or wiregage elements are identical in their mechanical history and metallurgical composition. The major variable left is, of course, the bonding cement and the manner of its use.
Temperature Compensation Techniques
Authors: Friedman Richard
Published: September 2009

Before going into a discussion of temperature compensation techniques, it is important to consider for a moment the kind of information a strain gage can provide under constant or variable high temperature conditions. Under constant temperature conditions, it is possible to allow time for all specimen parts to come to the same temperature before an external load is applied. If the entire specimen is made of the same material, it may be considered unstressed although the various parts of the specimen have new dimensions and the strength characteristics have changed. This assumes that the specimen is free to expand without restraint. If a load is applied to the specimen, strain gages suitably mounted on the specimen should measure strain due to applied load. Under conditions of rapid heating, we know that thinner sections will increase in temperature more rapidly than thicker sections and strains develop in the specimen due to structural restraints. These strains are to be measured as well as strains due to externally applied loads. It would seem that an acceptable device for measuring strain should provide very low, ideally zero, output with change in temperature when applied to a homogeneous specimen. It is only natural that in the development of such a gage, the greatest emphasis be placed on a resistance type strain gage, since this gage has served so well for all types of strain measurements under ordinary temperature conditions. It is also important to consider that millions of dollars have been invested in instrumentation equipment for use with resistance strain gages.
Problems in Thermal Stress Measurements
Authors: DeMichele D. J.
Published: September 2009

Problems requiring experimental determination of stresses in structures subjected to high temperature environments can be categorized as problems in which it is necessary to determine:

1. Vibratory stresses only (static stresses on which vibratory stresses are superimposed are ignored).

2. Stresses caused by external loads applied over relatively long time intervals in high, but constant, positive temperature environments.

3. Stresses in structures which may or may not be subjected to external loads but which occur in environments characterized by temperature distributions varying in space and with time.
High Temperature Strain Gage Evaluator
Authors: Martina C. K.
Published: September 2009

Data contained in the published literature on high-temperature strain gages are frequently inadequate for immediate use. In most cases, the information available is based either on a different gage type or on the same gage bonded to a different material. Two alternative procedures can be followed to overcome this obstacle: acceptance of an enlarged uncertainty figure or performance of a separate test. Testing is usually imperative and urgent. At the Bell Aircraft Corporation, a quick cantilever-test-method of handling strain gage problems has provided usable information. However, lacking clear-cut separation of variables, such test results are more properly a system check and do not provide basic information. They are the offspring of the jury rig. Due to the pressures of the missile programs, we at Bell were forced until recently to content ourselves with the jury rig. Now, we hope to complete a strain gage analyzer worthy of its name. While the prime justification for this analyzer is high-temperature work, its basic elements can be used in a variety of environments.
High-Temperature Strain-Gage Testing at Rolls-Royce
Authors: Drew D. A.
Published: September 2009

Measurement of the change in gage factor with variation in temperature is accomplished at Rolls-Royce (England) by means of a very simple dynamic test rig. The device, shown in Fig. 1, consists of a tuning fork whose tynes are recessed through milling near the tyne roots. The test gages are applied to the bottom of the recess. The base of the fork is placed in a tubular oven, and the gage temperature accurately measured by means of a thermocouple welded to one of the tynes.
Development and Application of High-Temperature Strain Gages for Stress Measurements in Jet Engines
Authors: Anderson B. R.
Published: September 2009

This paper covers recent advancements in the development and application of high-temperature strain gages for stress measurements in jet engines. Development of high-temperature strain gages can be divided into three areas: (1) alloys, (2) cements, and (3) fabrication and application techniques. In the Aircraft Gas Turbine Division, the measurement of vibratory stress and static stress are both of primary importance. For vibratory stress measurement, a high-temperature strain gage has been developed which will operate at temperatures up to 1500 F continuously and up to 1800 F for short periods of time. For static stress measurement, a self-temperature — compensating, high — temperature strain gage has been developed for application on specific alloys up to 850 F. Developments to increase the temperature range of both of these gages are under way.
The National Role of Materials Research and Development
Authors: Baker W. O.
Published: September 2009

The Stone Age, the Bronze Age, the Iron Age (and in these heady times the Bone Age)—thus does the history of man recognize the pre-eminence of materials in the advance of civilization. Ironically, this ancient sense that the art and science of things—of structures, of tools, of clothes, of vehicles—was the essence of human progress, has inhibited an “intellectuality” of materials from forming until very recent years. That is, the nature and behavior of solids—of metals, wood, fibers, ceramics, minerals—have been assumed to constitute their own universe of old and occult knowledge. They were things in themselves (not part of a continuum of theory and concept), and thus both inaccessible and uninviting to the probing intellects who measured the courses of the remote and isolated stars, who measured and pondered the geometry of a ray of light and the colors of its waves, and even to those, like Maxwell and Humboldt and Huygens, who saw deeply into the immaterial fluxes of electromagnetism and of heat. Even in this century the triumphs of Einstein in radiation physics, of Planck, Bohr, and Heisenberg in quantum and wave mechanics, were attached to separate atoms. The hydrogen molecule, the gas ensemble, the electron, the proton, the nuclear particle, the electromagnetic field around it—these seemed to be the things that man could understand, or as Professor Weisskopf put it not so long ago: “If you understand hydrogen, you understand everything that is understood.”
Mechanical Properties of Semiconductors
Authors: Hobstetter J. N.
Published: September 2009

Significant interest in the mechanical properties of semiconductor materials dates from about 1952 when Gallagher (1)2 first demonstrated that the supposedly brittle substance germanium becomes plastic at sufficiently elevated temperatures. Almost all we know about the mechanical behavior of this and similar materials has been learned in the intervening eight years so the whole subject falls well within the scope of a symposium on “Recent Progress in Materials Science.”
Dislocation Motions and the Yield Strengths of Solids
Authors: Gilman J. J.
Published: September 2009

At the yield stress of a crystal its behavior suddenly changes from elastic to plastic; in other words, the plastic strain rate suddenly becomes finite and sometimes quite large. In terms of dislocation movements the plastic strain-rate, ˙γ, depends on the Burgers vector, b, of the dislocations in the crystal, the average velocity of the dislocation motions, v¯, and the number of dislocations moving per unit area (ρ). These quantities are related by a simple equation (1): γ˙=bρv¯ which has been verified by Johnston and Gilman (2) through direct measurements of dislocation densities and velocities in lithium fluoride crystals. Since b is a constant, and ρ cannot change unless dislocations move, the yield stress is related to ¯ν. Thus, in order to understand the nature of the yield stress, the first question that requires an answer is: What determines the stress needed to move dislocations at a large average velocity? Is it the stress needed: (a) to operate sources of dislocations such as Frank-Read sources? (b) To pull dislocations away from Cottrell atmospheres? (c) To drive dislocations through a forest of other dislocations? (d) To overcome an intrinsic “plastic resistance” of the crystal structure? Also, do various types of crystals (metallic, ionic, or covalent) depend on different ones of these factors, or is plastic flow in all crystals dependent on the same factor? The thesis that will be developed here is that factor (d) is the most important one for all single phase crystals.
Irreversible Effects of High Temperature and High Pressure on Organic Materials
Authors: Bradbury E. J. , Leininger R. I.
Published: September 2009

Equipment and techniques employed in ultrahigh-pressure-compression treatment of polymeric materials are described. Results of exploratory studies with several organic polymers, semiorganic compounds, and several chemical compounds are presented and discussed with respect to similar or related studies found in the literature. Physical and structural changes were found as a result of compression treatment on different materials. Although generically related materials appeared to have somewhat similar compression behavior, no general compression effect was observed.
Effects of High Pressure and Temperature on the Mechanical Properties of Metals and Alloys
Authors: Radcliffe S. V.
Published: September 2009

The application of high pressure to metals and alloys can cause changes to their structures and mechanical properties observed subsequently. The nature and magnitude of these changes depends primarily on such factors as the type of material and its initial structure, the nature and magnitude of the pressure applied (static or dynamic), the types of phase transformation or precipitation induced by changes in pressure at constant temperature (abaric transformation) or in temperature at constant pressure (athermal transformation and quenching followed by isothermal transformation), and the accidental introduction of plastic distortion during the pressure cycle.

The contributions and interrelationships of these various factors are discussed for different metals—in particular, iron and some alloys of iron. Attention is given to the effects of crystalline anisotropy, changes in phase equilibria and reaction kinetics, quasi-hydrostatic pressure conditions, and shock-induced imperfections.
Effects of High-Pressure, High-Temperature Treatment on the Properties of Electronic Materials
Authors: Warekois E. P.
Published: September 2009

The application of high pressures and temperatures will usually produce very drastic changes in the properties of a material. These changes can be crystallographic transformations or severe distortions and are evidenced by changes in electrical resistivity. In the case of electronic materials, which are characterized by discrete energy bands, the changes are of such magnitude that entirely new species of the material are produced. This paper discusses some of the high-pressure phases produced in indium antimonide and some of the intermetallic tellurium compounds, including tin telluride. Examples of new materials synthesized under pressure are illustrated by a discussion of a samarium selenide compound. A general discussion of the stability of these high-pressure phases is presented with specific examples in the mercury-sulfur-selenium and mercury-cadmium-telluride systems.
1-2 Clean Surfaces, Their Preparation and Characterization
Authors: Roberts R. W.
Published: September 2009

In many areas of chemistry, physics, and technology it is important to have a detailed understanding of the structure of clean solid surfaces, their physical properties, and their chemical properties. Some representative areas where this understanding is necessary are adhesion, friction, boundary lubrication, crystal growth, catalysis, composite materials, corrosion, microelectronics, field emission cathodes, gas/solid energy exchange, etc. To generate such information it is necessary to probe the chemical and physical nature of well-defined, clean surfaces. Surface defects, surface roughness, and adsorbed impurities all complicate the attainment of a clean surface. For the purpose of this paper a clean surface is taken to be “one free of all but a few per cent of a single monolayer of foreign atoms, either adsorbed on or substitutionally replacing surface atoms of the parent lattice.”
1-3 Gas-Surface Processes and LEED
Authors: May J. W.
Published: September 2009

Low energy back-reflection electron diffraction (LEED) is a powerful method for studying monocrystalline surfaces, either in the clean state or with adsorbed substances. Weak penetration of slow electrons means that mainly surface atoms are important for scattering whether they belong to the substrate or to an adsorbed species. Clean surfaces can be produced and studied prior to adsorption experiments. LEED studies show that gases can be adsorbed in 2-dimensional arrangements peculiar to the specific crystallographic orientation of a particular single crystal substrate. Chemisorption often causes reconstruction of the surface with substrate atoms moving to new positions to incorporate foreign atoms in 2-dimensional matrices. Heating gas-covered surfaces may bring about faceting to expose other crystallographic planes (gross reconstruction). Heating may also cause the adsorbate to decompose, dissolve in the substrate or partially evaporate to leave behind different structures of lower coverage. Experiments illustrating many of these features are described for nickel and tungsten surfaces after adsorption of oxygen.
1-4 Atomic Surface Structure of the Common Transition Metals and the Effect of Adhesion as Seen by Field Ion Microscopy
Authors: Müller Erwin W. , Nishikawa O.
Published: September 2009

The field ion microscope has so far mostly been used for the direct observation of atomic details on the surface of refractory metals. The application of the instrument to the common transition metals like iron, cobalt and nickel was difficult because of the high rate of field evaporation and the field induced disordered structure of the surface layers of these metals in a field of about 440 MV/cm which is necessary for a high resolution helium ion image. In order to obtain a stable and undisturbed surface, it is necessary to find an imaging gas which fulfills the following conditions: the imaging field is lower than the evaporation field of the specimen metals and the field stress on the metal surface at the evaporation field does not exceed the yield stress of the metals. Hydrogen as an imaging gas gives a stable image of the common transition metals and the field induced chemical reaction of hydrogen with the metals decreases the evaporation field considerably. However, the resolution of the pure hydrogen ion image even at 21°K is only 4A and the rearrangement of surface atoms due to the chemical reaction is severe and strongly temperature dependent. A satisfactory image quality is obtained with helium containing a very small addition of hydrogen which reduces the evaporation field so that the metal does not yield mechanically at this lower field stress. Loosely bound hydrogen molecules at the surface act as intermediate collision partners between incoming helium atoms and the heavy surface metal atoms, thereby increasing the helium accommodation and lowering the imaging field. Field ion micrographs of iron, cobalt, nickel and carbon steel now show detailed and undisturbed surface structures.
2-2 Space Simulation Testing of the Adhesion of Materials
Authors: Rittenhouse John B.
Published: September 2009

A discussion of the space environment as it influences the possibility of adhesion of engineering materials generally used in spacecraft construction will be given. The interaction of material surfaces with the space environment will be presented.
2-3 Adhesion of Metals in High Vacuum
Authors: Hordon M. J.
Published: September 2009

The adhesion or cold welding behavior of a variety of metals and alloys was investigated in the temperature interval 20°–150°C in which diffusion enhanced bonding generally was negligible. The tests were performed at vacuum levels below 1 × 10−8 torr to ensure that surface oxides, disrupted or removed by vibratory abrasion, would not readsorb monolayer films within the surface exposure time. The efficiency or effectiveness of metallic contact adhesion, determined as the ratio of the interfacial rupture stress Sr to the compressive yield strength, Sy was related to physical properties including plastic deformation rate, yield strength and lattice structure.