bluuebunny/crossref_metadata_2025 huggingface dataset:
Alloying Precipitation Hardening Stainless Steels for Strength and Stability
Authors: Perry D. C. , Marshall M. W.
Published: September 2009

Stainless steels 17-7 PH and PH 15-7 Mo could not be used in their highest strength conditions because they lacked toughness. Overaging was employed to obtain good fracture strengths but with a considerable sacrifice in useful tensile properties. Even in the overaged condition, these steels become embrittled after long-time exposure at temperatures of 600 to 700 F.

This paper described alloy development studies that have resulted in a new precipitation hardening steel, PH 14-8 Mo. This stainless steel has exceptionally high net fracture strengths in excess of 225,000 psi. Long time exposure studies at temperatures of 400 to 750 F show marked resistance to embrittlement.

This breakthrough in toughness and stability is attributed to close control of chemical composition, especially carbon, phosphorus, sulfur, and nitrogen. The merits of air and vacuum melting processes in obtaining the desired results are also discussed.
Roping and Intergranular Corrosion of 430 Stainless Steel
Authors: Parker E. A.
Published: September 2009

Heat treating Type 430 stainless steel above 1650 prior to cold rolling in order to produce a lower roped steel results in sensitization of the steel on fast cooling. This sensitization causes rapid intergranular corrosion in hot nitric-hydrofluoric acid solutions unless the steel is desensitized prior to immersion. The time-temperature relationship for desensitization is given. In addition, a possible mechanism for sensitization-desensitization in ferritic stainless steels is presented.
The Design of Coal Sampling Procedures
Authors: Bertholf W. M.
Published: September 2009

Equations relating the fundamental sampling constants of a coal (as variances) to the observed variance of a series of samples composed of N increments each of weight w are given. Suggestions are made for estimating the “trend” variance and charts are given for the more precise determination of the expected unit increment variance and the variance of the process of reduction and analysis of the gross sample. Several numerical examples are given to show the effect of changing the increment weight on the number required and to show the effect of changing the specified number on the total sample weight.
Solders, Fluxes, and Techniques for Soldering Aluminum
Authors: Dowd J. D.
Published: September 2009

Aluminum can be soldered using a wide variety of solders, fluxes and techniques. The solders for aluminum are usually alloys of zinc, tin, cadmium and lead, although small amounts of other elements have been added to many such solders. Before soldering aluminum, the oxide film on the surface must be removed, either mechanically while the surface is covered with molten solder, or with fluxes. Chloride-free organic fluxes can be used when soldering with low-temperature solders, but chloride-containing salt fluxes must be used when soldering with higher temperature solders.

All of the common soldering techniques can be used in soldering aluminum; and in addition, there are several techniques more applicable to aluminum than to other metals. These include rub soldering, ultrasonic soldering, and reaction-flux soldering. For some application, it may be desirable to plate the aluminum with copper, nickel or some other metal and then solder using procedures applicable to the plating metal.

The use of soldering as a method for joining aluminum depends largely upon the performance required of the resultant joints. Of the performance characteristics, resistance to corrosion is by far the most important, although in some cases other factors may be of consequence. The resistance to corrosion of soldered joints in aluminum varies greatly, depending upon solder composition, joint design, use of protective coatings, and the environment in which the soldered joints are exposed. Sound soldered joints that are adequately protected can be expected to give many years of satisfactory service in most environments.
Ultrasonic Soldering of Aluminum
Authors: Jones J. Byron , Thomas John G.
Published: September 2009

Ultrasonic techniques permit soldering of aluminum without the use of any fluxes whatsoever, with the elimination of corrosion attack resulting from flux residue or inadequate cleaning after soldering. Using these techniques, aluminum joints were fabricated with three binary solder alloys and two ternary alloys and were exposed to two corrosion media—hot aerated distilled water and salt water.

Data showing the decay of joint strength as a function of time of each solder in each environment are presented. Corrosion attack was observed to cause separation of the joints along the solder-aluminum interface. This localized penetration has been explained on the basis of a high galvanic potential at the interface resulting from the diffusion of solder constituents into the aluminum.

There are many applications for soldered aluminum assemblies where corrosion is not a factor or where selection of a suitable solder permits reasonable life in a corrosive environment. Ultrasonic equipment is available covering a broad range of applications, from diminutive precise devices for silicon transistor connections to large units for continuous coating of metal strip materials.
Soldering in Semiconductor Devices
Authors: Lootens W. F.
Published: September 2009

Semiconductor devices are very sensitive to surface contamination, and soldering flux is like a death warrant to the device. It is possible to do most of the soldering on these devices without flux by using the correct materials, temperature, and atmosphere. Illustrations of examples of how this has been done are shown. Some of the requirements for various applications are given. Certain metals, if used on semiconductor materials, may give trouble even if they occur only as an impurity in the solder. These metals are noted along with the effects they would have.
Industrial Survey of Paste Solder Alloys
Authors: Williams Harold R.
Published: September 2009

The purpose of this paper is to correlate the scattered data on paste solders for future standardization.

The two basic objectives in using paste solders are (1) to simplify hand soldering through automatic application of paste solder and, (2) to bring about an automatic heating-and-soldering cycle. In the development of paste alloys, many chemical and physical obstacles had to be overcome to reach these objectives. Examples of good and bad applications are illustrated. Also, several interesting applications in various fields are described in detail.

Six typical processes of heating are described and merits of equipment evaluated. Loose fitting joints are to be avoided, and parts designed for a close fitting “microfilm” joint seem desirable. Paste solders and automation methods seem to go hand in hand, but application techniques have been slow to develop. Five fundamental methods of paste solder application are brought out in some detail.

It is suggested that standards for paste solder alloys should be established in line with their ability to withstand corrosion using pure rosin as a standard. Four divisions could be made in accordance with present applications. Also, a numbering system based on the approximate melting point (close to the liquidus) has been suggested as more understandable by industry. A combination of the two would be a key to identify each paste solder alloy.
Corrosive Fluxes—Their Role in Soldering
Authors: MacIntosh Robert M.
Published: September 2009

The efficiency of a soldering operation depends to a great extent on the correct choice of flux. Fluxes are chosen on the basis of effectiveness and rapidity of fluxing action. The corrosive type fluxes, consisting of inorganic acids and salts, fulfill both functions. Flux compositions suitable for the joining of the common metals and alloys are discussed in this paper. Due regard is given to the removal of flux residues.
The Use of Rosin and Activated Rosin Fluxes
Authors: Disque Frederick C.
Published: September 2009

Considerable information has been published over the past twenty-five years on the subject of fluxes for use in electronic manufacturing—much of it very general, much of it dealing with broad principles, and some of it based on conjecture and incomplete or faulty experimental evidence. The purpose of this paper is to review briefly the history of rosin base fluxes and to point up the need for a better understanding of the types available and their advantages and disadvantages.
Tension Testing of Plastics
Authors: Reinhart Frank W.
Published: September 2009

It is quite evident from remarks made in many groups discussing the technical aspects of plastics, that there is not only a serious lack of understanding of the nature and limitations of tension test data on plastics but also a lack of awareness of the technical details that must be followed to obtain reliable results. It requires no particular technical competence to brush aside a set of tensile data, particularly when it contains some poorly obtained results, with the remark “What do tensile data mean anyway?”. Reliable tensile data properly analyzed do have meaning and can be used to advantage by those who are willing to give serious study to such a mundane subject.
Tension Testing of Adhesives
Authors: Dietz Albert G. H.
Published: September 2009

Adhesives must be tested as component parts of a bond. This is the crux of many of the difficulties and uncertainties associated with the evaluation of adhesives. Their properties in bulk may be different from the properties determined in bonded assemblages. Consequently, the testing of adhesives involves the simultaneous testing of the associated adherends, and the interactions of the two profoundly affect the results.
Extension of Sensitivity in Analysis of Impurities in Solids by Mass Spectrometry
Authors: Stevens C. M.
Published: September 2009

There are two commonly used techniques for the analysis of impurities in solids by mass spectrometry—spark analysis using a double focusing mass spectrograph with photographic film recording, and isotopic dilution with chemical separation and isotopic analysis. At the 1951 Symposium on Chemical Analysis of Inorganic Solids by Means of the Mass Spectrometer held by ASTM Committee E-2 on Emission Spectroscopy, Inghram (1) and Hipple (2) gave papers describing these methods in detail. This discussion presents a brief review of these methods, the outstanding improvements since 1951, the limitations of the methods, and, finally, the general trends for overcoming these limitations. This discussion emphasizes the isotopic dilution method and high-sensitivity surface ionization analysis, primarily as used for nonroutine and research type analysis problems where the most sensitive methods are in use.
Friction Properties of Pavements at Different Speeds
Authors: Schulze K H , Beckmann L
Published: September 2009

Based on measurements with a locked-wheel trailer on wet pavements, curves indicating friction coefficients versus speed can be plotted and classified by the degree of decrease of the coefficient with increasing speed. A correlation was found between the mean width of the voids in the pavement surface and the steepness of the friction-speed curve: the closer the surface, the steeper the curve.

Friction coefficient and wear index differences between outside and inside lanes of four-lane highways provided a measure for the change of skid resistance caused by traffic. The mean decrease of the locked-wheel coefficients differed significantly at high speeds for mastic asphalt, fine asphalt concrete, and portland cement concrete pavements. Mastic asphalt pavements had the highest rates of decrease; cement concrete had the lowest. A significant relationship was found between the locked-wheel coefficients and the friction coefficients at 17 to 20 per cent slip (approximately the maximum coefficients) at single speeds up to 50 mph and for theoretical braking distances calculated by integration from the friction-speed curves.
Variation in Highway Slipperiness Characteristics with Location
Authors: Mahone D C
Published: September 2009

This study compares the slipperiness characteristics of various pavement areas, some of which are not easily accessible to conventional road slipperiness measuring methods. In the study, the British portable tester was used to compare (1) slipperiness characteristics of wheel tracks with those of other lateral areas of the highway pavement, and (2) the characteristics of level tangents to those of other symmetrically shaped areas.

The 26 sites tested covered a wide range of surface types, textures, and coefficients of friction. From the data obtained, it was concluded that the coefficient of friction varies both longitudinally and laterally on a highway surface. The one steel deck bridge tested was found to be extremely slippery. The lowest coefficients of friction were noted in wheel paths, on paint lines, and on bleeding asphalt spots.
Decrease of Skid-Resisting Properties of Wet Road Surfaces at High Speeds
Authors: Obertop DH F
Published: September 2009

A theory is developed to show that the production of steam by the transformation of energy causes the decrease of skid-resisting properties of wet road surfaces at high speeds. The theory enables us to make quantitative computations regarding the relation between the friction coefficient and the speed.
Determination of Intermolecular Forces by Surface-Chemical Techniques
Authors: Fowkes F. M.
Published: September 2009

The intermolecular forces operative between adjacent phases include the ever-present dispersion forces; various dipole and ionic interactions; hydrogen-bonding and electron-transfer complexes; and the metallic bond. For any given interface the nature of the forces that can operate between the two materials may reduce to dispersion forces alone or dispersion forces plus hydrogen-bonding. Means to evaluate the magnitudes of these interacting foices, based on measurements of contact angles, interfacial tensions, and heats or free energies of immersion or adsorption, are set forth. Examples are shown in which the wettability of solids by liquids is best predicted by considering the actual type of intermolecular forces involved at the interface.
Flexural Moduli and Deflection Temperatures of Various Epoxy Formulations
Authors: DeLollis N. J.
Published: September 2009

Epoxy resins are continually being modified in order to achieve improved performance and processing. The effects on flexural modulus and deflection temperatures are studied for a system with an alumina filler and for one without an alumina filler at varying concentrations of the curing agent. In addition flexural moduli for seven flexibilized systems are studied at temperatures from −54 to +74C.
Performance of Phenolic and Urea Resins in Particle-Board Binding
Authors: Kamrath R. H.
Published: September 2009

This paper compares the performance of liquid urea-formaldehyde and phenol-formaldehyde resins—two of the most commonly used binder systems for particle board. Cost, manufacturing variables, and board performance are discussed and previous research findings by other investigators and present actual plant and laboratory experience of one board manufacturer are summarized.

Urea resin maintains an economic advantage over phenolic resin because of lower unit cost, ease in handling, and shorter press-cycle time required. However, under favorable conditions, phenolic resin can develop greater bonding efficiency because of its resistance to advanced curing, improved resin distribution qualities, and tolerance to many production variables, particularly moisture content. Slower curing phenolic binder generally requires longer press-cycle time and higher press temperature than a catalyzed urea binder.

Equivalent particle board properties are achieved with both binders when operating at conditions suitable to each system, except in the case of board durability and short-term water absorption. Unfinished, phenolic-bonded particle board shows a distinct advantage in durability over a urea board under cycling temperature and relative humidity conditions. Because of the alkaline nature of phenolic resin, boards with this binder usually have somewhat higher water absorption.
Polyken Probe Tack Tester
Authors: Hammond F. H.
Published: September 2009

The Polyken probe tack tester is a portable device for measuring the tackiness of pressure-sensitive adhesives and cements. The tester provides a means of bringing the tip of a probe into contact with the adhesive at controlled rates, contact times, and temperatures, and subsequently breaking the adhesive bond thus formed, also at controlled rates. The maximum force during the break is taken as the measure of tackiness.

Data are presented to illustrate the utility of this instrument on commercial pressure-sensitive adhesive tapes. Tack values for all tapes increase with increasing pressure, with increasing time of contact, and with increasing rate of separation. Tack values decrease with increasing temperature. Tack value is shown to be independent of the thickness of the adhesive. Reasons for the above are discussed and the reproducibility and statistical parameters of the test are provided.
Strength of Epoxy Adhesives when Stressed to Failure in Milliseconds
Authors: Wegman R. F. , Tanner W. C.
Published: September 2009

The data presented demonstrate that the adhesives tested exhibit a greater resistance to rapidly applied or dynamic loads than they do to loads applied at static rates. The difference observed between the dynamic and static strengths is dependent upon the formulation of the particular adhesive. At low temperatures where the molecular motion is greatly restricted, the bond strengths obtained do not as a rule vary much with rate of load. However, as the test temperature increases, the molecular motion increases, and unless some factor is present that will restrict this movement the resistance to applied loads becomes more time dependent.
An Evaluation of the Field Vane Test in Sensitive Clay
Authors: Eden W. J.
Published: September 2009

For the past 10 years, the Division of Building Research has employed the field vane apparatus to measure the undrained shear strength of the sensitive Leda clays of Eastern Canada, which have an overconsolidation of from 0.3 to 5.0 tons/ft.2 The apparatus has also been used in the nearly normally consolidated varved clays of northern Ontario and Quebec. This paper summarizes this experience and attempts to assess the usefulness of the field vane in relation to other field evidence.

For the soft, lightly overconsolidated clays (undrained shear strength less than 0.5 tons/ft2), the field vane yields consistent undrained strengths which have correlated well with other field evidence. For stronger clays (overconsolidated from 3 to 5 tons/ft2), the value of field vane tests is questionable.
Dynamic Cone for Shallow In-Situ Penetration Testing
Authors: Sowers George F. , Hedges Charles S.
Published: September 2009

Field calibration of a portable dynamic cone penetrometer was made to determine a penetration resistance relationship with the standard penetration resistance. The penetrometer has been found useful in the inspection of footing foundations and for light field exploration where the standard penetration range of limits is generally known. The test data show that it is capable of approximating the standard penetration resistance for the virgin soils of the southeastern United States.
Laboratory Methods for Grading Setting Qualities of Paving Asphalts
Authors: Santucci L. E. , Schmidt R. J.
Published: September 2009

Tender mixes are defined as asphalt concrete (AC) mixes that shove excessively under steel wheel rollers, do not densify, and remain soft for extended periods of time after construction. Improper aggregate gradation, very little aggregate angularity, low filler content, high aggregate moisture content, and improper compaction procedures are the principal causes of tender mixes. However, under critical mix conditions the type of asphalt used can also determine the tenderness, or conversely the toughness, of an AC mix. Laboratory tests are examined to establish those physical properties of the asphalt that influence the toughness of a mix. These properties are related to the pavement toughness as measured in a full-scale paving laboratory in which actual paving construction practices are simulated. Pavement toughness is established at 100 F and at a uniform mix density. The penetration at 77 F and viscosities at 100, 140, and 275 F (or any combination of these properties) of the original asphalt show very poor to fair correlations with pavement toughness. An excellent correlation is obtained between pavement toughness and the viscosity at 100 F of asphalts recovered from test pavements. The viscosity at 140 F of aspalts exposed in the rolling thin film oven (RTFO) also relates well to pavement toughness. An excellent correlation for all asphalts tested results when the rolling thin fim (RTF) viscosity of the asphalt and toughness of the mix are compared at the same test temperature of 100 F. The viscosity at 140 F of an RTF residue is proposed as a practical method for grading setting qualities of paving asphalts. This viscosity can be determined rapidly and routinely in the laboratory.
Heat-Resisting Metals for Gas-Turbine Parts
Authors: Cross Howard C. , Simmons Ward F.
Published: September 2009

This report shows the results of high-temperature tests on heat-resisting alloys carried out under National Defense Research Committee Project NRC-8 to study and evaluate new alloys and supply needed information to the Armed Forces and their contractors.

The materials studied ranged from modified 18 per cent chromium-8 per cent nickel steels to practically iron-free cobalt-chromium and cobalt-chromium-nickel alloys with additions singly or in combination of molybdenum, tungsten, columbium, tantalum, titanium, aluminum, boron, and nitrogen.

Short-time tension tests were made on the precision-cast cobalt-base alloys at 1000 to 1600 F.

Stress-rupture tests were made at 1500, 1600, and 2000 F. to determine the stresses for rupture in times varying from 100 to 1000 hr.

Creep tests were made at 1350, 1500, and 1600 F. to pick out the better alloys and to determine the stresses required to produce creep rates of 0.00001 per cent per hour.

The cast cobalt-base alloys show better stress-rupture and creep properties generally than the forged alloys, except for creep resistance at 1350 F. Design curves based on both stress-rupture and creep data at 1500 F., show that for low values of total deformation, some of the forged alloys are superior to the cast alloys.

Relaxation creep tests for predicting high-temperature bolting performance were made on a few alloys at 1050 to 1500 F.
Metallurgy of High-Temperature Alloys Used on Current Gas Turbine Designs
Authors: Badger F. S. , Sweeny W. O.
Published: September 2009

Other papers presented in this symposium have covered rather completely the Government-sponsored laboratory work carried on in the development and testing of high-temperature alloys, and have included technical data on their analyses, physical properties, and high-temperature properties.
Alloys and Ceramic Materials for High-Temperature Service
Authors: Cross Howard C.
Published: September 2009

When the National Defense Research Committee Projects NRC-8, NRC-41, NRC-88, and NRC-90 contracts were discontinued on October 31, 1945, many interesting and unsolved problems still existed that needed further study. These problems concerned ceramic materials as well as metals for gas-turbine service. The Office of Research and Inventions, Navy Department, entered into a contract with Battelle Memorial Institute to carry on research on “Alloys and Ceramic Materials for High-Temperature Service.” Cooperating with Battelle on a subcontract basis are Rustless Iron and Steel Corp., Crane Co., The Midvale Co., and the University of Michigan.
The Role of TGA-DTA in the Initial Evaluation of the Solid State Forms for Pharmaceutical New Chemical Entities, Part 2: Evaluation of Mixed Forms
Authors: Redman-Furey Nancy L. , Dicks Michael L. , Godlweski Jane , Vaughn Dana C. , Collins Wendy J.
Published: September 2009

TGA-DTA plays a central role in the strategy outlined for early evaluation of the solid state forms available to pharmaceutical new chemical entities. Understanding of the solid state forms becomes more difficult when individual samples present as mixed forms, especially when it is not immediately recognized that the samples represent a mixture. In this study, TGA-DTA, in combination with light microscopy and powder X-ray diffraction, provided immediate evidence that samples represented mixed solid state forms. The initial assessment was made using as little as 5 mg of sample. Hygroscopicity challenges provided further proof for mixed forms. To make a definite assignment of the solid state forms present, isolation of pure phases of the suspected individual forms was necessary. Success of this testing strategy is illustrated using an example of mixed salt stoichiometry and mixed hydration states. A hierarchy is suggested for efficient isolation efforts when a complex mixture of solid state samples is present.
Quantitative Mass Measurements from Mass Spectrometer Trend Data in a TG/MS System
Authors: Slough Carlton G.
Published: September 2009

The use of mass spectrometry (MS) in the identification of evolved gaseous species in thermogravimetric (TG) experiments is well established. The mass spectrometer can be attached directly to the outgas port of the thermogravimetric instrument. Mass spectrometers have the ability to detect species to 1 ppm or better, and the detection is done in real time as the TGA scans. Typically, the mass spectrometer is used for identification only. However, there are situations where it would be desirable to quantify the MS data. For example, when two or more species are evolved during a weight transition, the total weight loss is known from the TGA, but the weights for the individual components are unknown. Calibration techniques for quantifying MS data are already well established. Following one of these techniques, we show that trend data from a mass spectrometer can be used to approximate the amount of material evolved for low m/e ratio species such as water and carbon dioxide. The process involves first calibrating the system using a sample that only gives off the gaseous species of interest. Multiple runs at different initial weights provide the data for the calibration. A correlation between mass loss as measured by the TGA and ion current increase as measured by the MS is then constructed. In this study, the technique is applied not only to overlapping transitions but also to the quantification of reaction products from gases released during a TGA experiment. An attempt is also made to quantify the accuracy of the technique.
Separation of Overlapping Processes from TGA Data and Verification by EGA
Authors: Artiaga Ramón , Cao Ricardo , Naya Salvador , González-Martin Bárbara , Mier José L. , Garcia Ana
Published: September 2009

A typical problem when analyzing the kinetics by dynamic TGA of polymer degradation consists in that different models can fit equally well, or the model does not fit the TGA data. It has been suggested that this is due to the presence of overlapping processes. High resolution TGA helps to clarify the problem in some cases, but in many other cases the problem remains unsolved. In this work, a dynamic TGA curve showing overlapping processes of degradation, typical of polymer thermal degradation, is fitted by a multiple logistic regression model. The regression function is a mixture of logistic functions where each single logistic function is weighed by a factor that represents the amount of the sample that takes place in the process represented by that function. A software program was developed to fit the data to the logistic mixture model by estimation of the parameter values. Additionally, the correlation of parameter estimates was performed by the S-Plus software. The regression was performed so that the best fitting shows the number of single decomposition processes that take place along the experiment, even if they are overlapping. Other parameters have the physical meaning of mass loss rate and position of the process in the time or temperature domain. The study of the correlations of parameter estimates gives a new insight on how each component fits a logistic model. The parameters obtained describe the kinetic of the processes in a form totally independent of the Arrhenius model. The separation of processes allows for analysis of each single process by classical methods. Although the model is mathematically supported, verification was done by comparing the results with the FTIR spectra obtained from the gases evolved along the experiment. The FTIR analysis of the gases evolved from a TGA experiment confirms that the logistic mixture model is suitable to analyze a dynamic TGA trace. It was also found that the logistic mixture model is suitable to separate single components from FTIR spectra. Some differences were found in the location of the components along the time axis, comparing DTG and FTIR data. In the FTIR, the separated peaks are broader and appear shifted to longer times. It can be attributed to the delay and mixing of components that may occur during the gas carriage from the TGA furnace to the FTIR detector.
Photo Thermal Micro-Spectroscopy — A New Method for Infared Analysis of Materials
Authors: Slough Carlton G. , Hammiche Azzedine , Reading Mike , Pollock Hubert M.
Published: September 2009

Many modern materials are composite structures with complex morphologies that play a large role in determining the material function. The ability to investigate the relationship between structure and property on a microscopic scale can play a crucial role in material development. Micro-Thermal Analysis (μTA)™ is a unique set of analytical techniques for characterizing materials on a micrometer and nanometer scale. Micro-TA combines the imaging power of atomic force microscopy with the ability to analyze physical, mechanical, thermal, and chemical characteristics at a specific point of interest on the surface of a material. At the heart of the technique is a miniaturized thermal probe. In a new technique termed Photo Thermal Micro-Spectroscopy (PTMS), this thermal probe is used to detect temperature fluctuations in samples that have been irradiated by IR radiation. A Fourier Transform Infrared (FT-IR) spectrum can be constructed from this information. This paper describes the PTMS technique and discusses recent applications.
A Thermal Analysis Method for Measuring Polymer Flammability
Authors: Lyon Richard E. , Walters Richard N. , Stoliarov Stanislav I.
Published: September 2009

A thermal analysis method is presented in which controlled heating of polymer samples and complete combustion of the evolved gases are used to separately reproduce the condensed and gas phase processes of flaming combustion in a single laboratory test. Oxygen consumption calorimetry applied to the combustion gas stream gives the heat release rate history of the sample as a function of its temperature. The maximum rate of heat release and the temperature at which it occurs are polymer characteristics related to .re performance and flame resistance.
Thermal and Oxidative Properties of Physiologically Relevant Free Fatty Acids by Dielectric Analysis and Differential Scanning Calorimetry
Authors: Riga Alan T. , Alexander Kenneth S. , Williams Kevin
Published: September 2009

Physiologically relevant fatty acids and related organic acids are basic for human life. The essential fatty acids, linoleic, linolenic, and arachidonic acids, are sourced from vegetable seed oils (corn, sunflower, saflower), and margarines blended with vegetable oils. The functions of these special acids are in the synthesis of prostaglandins and membrane structures. Growth cessation and dermatitis occurs with a deficiency of the fatty acids. A typical therapeutic dosage of the essential fatty acids is up to 10 g per day. The polyunsaturated fatty acids. linoleic (9,12-octadecaidienoic), linolenic (9,12,15-octadecatrienoic), and arachidonic (5,8,11,14-eicosatetraenoic) are referred to as essential fatty acids. They unlike other lipids must be provided by diet. Arachidonic acid can be produced in the body by linoleic acid. This thermal analytical study is to determine fatty acids' physical transitions [melting] by DSC at low temperatures and their surface properties by low frequency dielectric analysis and relate those properties to the inherent amount of unsaturation in the fatty acids. It is our premise that the degree of unsaturation will affect low temperature melt temperature and electrical properties, e.g., electrical conductivity and complex permittivity. We have observed that the DEA properties of the air-aged liquid fatty acids indicate that the electrical conductivity and complex permittivity can be correlated with the degree of unsaturation. It is our objective to establish a relationship between the amount of unsaturation, number of double bond sites and the electrical properties, complex permittivity, and electrical conductivity.
Effects of Phase Transformations on Fatigue Endurance of a Superelastic NiTi Alloy
Authors: Wu Ming H.
Published: September 2009

It is well known that NiTi shape memory alloys exhibit superelasticity where a large elastic deformation proceeds under a constant stress due to the formation of stress-induced martensite. However, for most commercial NiTi alloys used in medical devices, the materials are processed in such a way that the R-phase transformation is apparently separated from the martensitic transformation. The B2 to R-phase change exhibits a much smaller shape change and a narrower hysteresis than does the B2 to B19' martensite transformation. Hence, the transformation temperatures as well as the thermomechanical properties associated with the R-phase are much more stable during cyclic deformation when compared to those associated with the B19' martensite. The crystallographic features for both martensitic and R-phase transformations are reviewed, and their effects on the tensile properties and rotating-beam fatigue endurance are studied in the present paper.
Thermoelastic Transformation Behavior of Nitinol
Authors: Perry K. E. , Labossiere P. E. , Steffler E.
Published: September 2009

The transformation behavior of Nitinol under uniaxial tension and four-point bending was investigated. A novel sample geometry produced from drawn tubing was used to observe the differences caused by localized phase transformation effects between the two types of loading and between samples with different process and load histories. Phase shifted moiré interferometry was used to provide full-field measurement of strain during the experiments. Optical resolution and grating coherence were sufficient to simultaneously resolve the strain fields within both the parent and transformed phases of the material. Evidence of both localized and uniformly distributed phase transformation is observed for the samples tested in tension while the bending results clearly indicate an asymmetric neutral axis and a complex reverse bending response for samples containing a strong R-phase component and tested at temperatures below critical transformation temperatures.
Functional Properties of Nanostructured Ti-50.0 at % Ni Alloys
Authors: Demers V. , Brailovski V. , Prokoshkin S. , Inaekyan K. , Bastarash E. , Khmelevskaya I. , Dobatkin S.
Published: September 2009

Ti-50 at % Ni alloy wire is subjected to cold-rolling (true strain e=0.3–1.9) and postdeformation annealing (200–700°C range). For all levels of cold work, the maxima of recovery strain and stress are obtained after annealing in the 350–400°C range. For the moderately-to-high cold-worked material (e=0.3–0.88), this annealing leads to polygonization, while for the severely cold-worked one (e=1.9), to the material nanocrystallization (grains of 50–80 nm in size). Nanocrystallized alloy generates 30 % higher recovery stresses (up to 1450 MPa) and 10 % higher completely recoverable strains (more than 8 %) as compared to the polygonized alloy, while having comparable mechanical properties in tension.
The Effect of Air Flow on Measured Heat Transport through Wall Cavity Insulation
Authors: Yarbrough David W. , Graves Ronald S.
Published: September 2009

The methods commonly used for determining the thermal resistance of insulations in wall cavities do not include the effect of air movement through the insulation. Contributions to the total building heating or cooling load include the change in enthalpy of air moving through an insulation and the heat flux through the insulation due to the imposed thermal gradient. The two effects are not independent since the air movement affects the temperature distribution in the insulation. A heat-flow-meter apparatus meeting the requirements of the Standard Test Method for Steady-State Thermal Transmission Properties by Means of the Heat Flow Meter Apparatus ASTM C 518 has been configured to allow uniform air flow across thermal test specimens. The air flow is parallel to the heat flow direction. Air is introduced into the specimen chamber of the heat-flow-meter apparatus from an external source. The heat-flow-meter with controlled air flow has been used to determine total heat-flow rates as a function of air-flow rate, air-flow direction, and temperature for commonly used wall cavity insulation.
The Effect of Vertical Distribution of Water Permeability on the Modeled Neutralization Process in Concrete Walls
Authors: Kishimoto Yoshihiko , Hokoi Shuichi , Harada Kazunori , Takada Satoru
Published: September 2009

The aim of this paper was to predict the durability of concrete walls. Because liquid movement is important in discussing the neutralization process, the vertical distribution of the permeability in a concrete wall was measured. In a 20 cm high sample, the permeability clearly showed a nonuniform vertical distribution. Next, an analytical model was proposed to predict the neutralization process taking into account the influence of acid rain. Based on this model, the simulation was carried out with permeability as a parameter. The results showed that neutralization was accelerated due to acid rain in regions with a high permeability and retarded in regions with a low permeability. Thus, it can be concluded that the influence of acid rain on the neutralization process may differ depending on the position in the concrete structure.
Engine Pumpability and Crankability Tests on Commercial “W”Graded Engine Oils Compared to Bench Test Results
Authors: Stewart Ross M.
Published: September 2009

This paper summarizes the correlations obtained between Cold Cranking Simulator viscosities and gasoline and diesel engine cranking data on 17 commercial engine oils. These engine oils include the new synthetic 5W/20 oils. The ability of an oil pumpability bench test to predict the pumpability properties of these 17 oils in a gasoline engine is also presented. The Cold Cranking Simulator Viscosities measured at temperatures from -40°F (-40°C) to 32°F (0°C) were studied to determine the necessity of measuring CCS viscosities of each “W” graded oil at its minimum expected use temperature.
Influence of the Viscosity of Polymer Containing Engine Oils on the Startability of Engines
Authors: Petery Curt von , Kruse Horst , Bartz Wilfried J.
Published: September 2009

Investigations using 4 monograde and 3 multigrade engine oils were performed by cold cranking an automotive engine to determine whether or not there is friction reduction due to the pseudoplastic behaviour of the multigrade engine oils. A comparison of the oils using viscometers indicated the viscometers ability to predict the “engine viscosities” over a temperature and shear rate range. Furthermore, this work determined whether results of viscometric measurements could be confirmed with the test engine. An answer was found to the question of the amount of hydrodynamic friction encountered when starting an automotive engine at low temperatures.
Polymer Stability in Engines
Authors: Wunderlich W. , Jost H.
Published: September 2009

Polymeric mineral oil additives are exposed to mechanical and thermo-oxidative degradation processes in the engine. For long lasting efficiency, they must show the highest possible stability to such attacks. The degradation processes are evident from and distinguishable by the molecular weight distribution of the polymer which can be measured with great accuracy by gel permeation chromatography (GPC), even for used oils. Results of such measurements are given for various types of VI improvers (polyalkyl methacrylates, ethylene-propylene copolymers and hydrogenated styrene-diene block copolymers) after exposure to Diesel and Otto engines. The influence of mechanical and thermo-oxidative degradation is discussed by means of model calculations. Comparative viscosity data elucidate the picture obtained from the distribution measurements.
Attapulgite as a Thixotropic Suspending Agent
Authors: Wolford John
Published: September 2009

Attapulgite is a hydrous magnesium aluminum silicate clay mineral with a unique structure made up of colloidal particles called spicules. Gellation takes place following dispersion when the spicules become attracted to each other, become entangled and form the matrix structure that thickens, entraps, and suspends solids. Proper dispersion and gelling is dependent on the amount of shear and length of time it is applied or the use of chemical means to facilitate dispersion. To achieve gellation chemically dispersed clay must come into contact with a chemical salt which causes spicules to associate with one another and the gel to instantly form. Attapulgite can also be used to structure organic systems with the proper use of a cationic surfactant. The basic advantages of attapulgite as a structuring agent are versatility, compatibility with a variety of liquid systems, functionality over a wide pH range, and resistance to attack by microorganisms. It is relatively economical and provides a thixotropic liquid system.
Water Conditioner Adjuvant and Fertilizer Formulation Effect on Micronutrient-Glyphosate Tank Mixtures
Authors: Bernards Mark L. , Penner Donald , Michael Jan
Published: September 2009

Tank-mixing foliar micronutrient fertilizers with glyphosate may reduce weed control because of antagonistic cations present in the spray solution. This research was conducted (1) to quantify the antagonism caused by various formulations of copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), and (2) to determine the extent that water conditioner adjuvants may prevent the antagonism from occurring. Most formulations of copper, iron, manganese, and zinc antagonized glyphosate efficacy on giant foxtail and velvetleaf. Formulations containing EDTA, HEDTA, or flavonol were the least antagonistic; those containing the sulfate salt or a lignosulfonic acid chelate were the most antagonistic. Tank mixtures including the adjuvant NT overcame the antagonism more often than those containing ammonium sulfate (AMS) or CANG. Two micronutrient blends, one with (MC) and one without (MS) the chelates citric acid and EDTA, both reduced glyphosate efficacy on giant foxtail and velvetleaf. The addition of AMS or NT to these blends increased velvetleaf control, but neither adjuvant overcame the antagonism.
Spray Retention Models for Arable Crops
Authors: Forster W. A. , Kimberley M. O. , Steele K. D. , Haslett M. R. , Zabkiewicz J. A.
Published: September 2009

A model has been developed explaining 92 % of the variance in spray retention by individual plants. The effects of formulation and plant morphology were represented as a logistic function, because this can accommodate retention close to 100 or 0 % whereas an additive model cannot. All inputs for the current model, except for the plant morphology factor, Mp, could be readily measured. Mp could be estimated by a linear regression relating Mp to the leaf surface roughness, as determined by the contact angle of a droplet of 50 % acetone on the leaf surface. The use of a logistic function, and inclusion in the model of total plant area, plan area, and contact angle to account for plant morphology, has provided an improved, practical, easily used universal agricultural spray retention model needing few inputs.
Taste-Guided Decisions Differentially Engage Neuronal Ensembles across Gustatory Cortices
Authors: MacDonald Christopher J. , Meck Warren H. , Simon Sidney A. , Nicolelis Miguel A. L.
Published: September 2009

Much remains to be understood about the differential contributions from primary and secondary sensory cortices to sensory-guided decision making. To address this issue we simultaneously recorded activity from neuronal ensembles in primary [gustatory cortex GC)] and secondary gustatory [orbitofrontal cortex (OFC)] cortices while rats made a taste-guided decision between two response alternatives. We found that before animals commenced a response guided by a tastant cue, GC ensembles contained more information than OFC about the response alternative about to be selected. Thereafter, while the animal's response was underway, the response-selective information in ensembles from both regions increased, albeit to a greater degree in OFC. In GC, this increase depends on a representation of the taste cue guiding the animal‘s response. The increase in the OFC also depends on the taste cue guiding and other features of the response such as its spatiomotor properties and the behavioral context under which it is executed. Each of these latter features is encoded by different ensembles of OFC neurons that are recruited at specific times throughout the response selection process. These results indicate that during a taste-guided decision task both primary and secondary gustatory cortices dynamically encode different types of information.
Sustained Axon–Glial Signaling Induces Schwann Cell Hyperproliferation, Remak Bundle Myelination, and Tumorigenesis
Authors: Gomez-Sanchez Jose A. , Lopez de Armentia Mikel , Lujan Rafael , Kessaris Nicoletta , Richardson William D. , Cabedo Hugo
Published: September 2009

Type III neuregulins exposed on axon surfaces control myelination of the peripheral nervous system. It has been shown, for example, that threshold levels of type III β1a neuregulin dictate not only the myelination fate of axons but also myelin thickness. Here we show that another neuregulin isoform, type III-β3, plays a distinct role in myelination. Neuronal overexpression of this isoform in mice stimulates Schwann cell proliferation and dramatically enlarges peripheral nerves and ganglia—which come to resemble plexiform neurofibromas—but have no effect on myelin thickness. The nerves display other neurofibroma-like properties, such as abundant collagen fibrils and abundant dissociated Schwann cells that in some cases produce big tumors. Moreover, the organization of Remak bundles is dramatically altered; the small-caliber axons of each bundle are no longer segregated from one another within the cytoplasm of a nonmyelinating Schwann cell but instead are close packed and the whole bundle wrapped as a single unit, frequently by a compact myelin sheath. Because Schwann cell hyperproliferation and Remak bundle degeneration are early hallmarks of type I neurofibromatosis, we suggest that sustained activation of the neuregulin pathway in Remak bundles can contribute to neurofibroma development.