bluuebunny/crossref_metadata_2025 huggingface dataset:
Growth Behavior of Surface Cracks in the Circumferential Plane of Solid and Hollow Cylinders
Authors: Forman RG , Shivakumar V
Published: December 2008

Experiments were conducted to study the growth behavior of surface fatigue cracks in the circumferential plane of solid and hollow cylinders. In the solid cylinders, the fatigue cracks were found to have a circular arc crack front with specific upper and lower limits to the arc radius. In the hollow cylinders, the fatigue cracks were found to agree accurately with the shape of a transformed semiellipse. A modification to the usual nondimensionalization expression used for surface flaws in flat plates was found to give correct trends for the hollow cylinder problem.
An Automated Photomicroscopic System for Monitoring the Growth of Small Fatigue Cracks
Authors: Larsen JM
Published: December 2008

An automated photomicroscopic system for monitoring the growth of small fatigue cracks was developed. Using a specimen that localized crack initiation within a small region, a 35 mm camera mounted on a reflected light microscope was employed to record the growth of small fatigue surface cracks of approximate lengths ranging from 25 μ to 2 mm. A microcomputer was used to control the testing, operate the camera, and record pertinent data. Upon completion of the test, photographs of the small cracks were projected onto a computer digitizing tablet in order to obtain digital crack length data. The precision of the resulting crack length measurements was approximately 1 μm for cracks on the order of 25 μm in length. In order to utilize the available crack growth data fully, a modified incremental polynomial method for reduction of data to the form of da/dN versus ΔK was developed. In general, the photomicroscopic system provided an efficient, cost effective method for monitoring the growth of small, naturally initiated fatigue cracks.
Investigation and Application of the One-Point-Bend Impact Test
Authors: Giovanola JH
Published: December 2008

This paper investigates a dynamic fracture test that produces smoothly varying stress intensity histories of controlled amplitude and duration. A test configuration has been adopted in which a simple edge-cracked specimen is loaded in bending by impacting it at the midsection without supporting it at the outer edges. The stress intensity history is measured by a strain gage near the crack tip and has approximately a sinusoidal time dependence.

The dependence of stress intensity amplitude and duration on the impact velocity and on the specimen material and dimensions has been determined both analytically and experimentally. The limit on the specimen aspect ratio to obtain a smooth stress intensity history controlled only by the first mode of vibration of the specimen has also been established. Stress intensity pulses of durations varying between 90 and 500 μs can be readily achieved, and the maximum amplitude can be independently adjusted over an order of magnitude (20 to 200 MPa m1/2).

The new experimental procedure has been used to measure the dynamic fracture toughness of 4340 steel (HRC 50) at three loading rates. Comparison of the dynamic results with the value of the static toughness indicates little strain-rate sensitivity of the fracture toughness of 4340 steel in the range of loading rates investigated (quasi-static to 3 × 106 MPa m1/2 s-1).
A Compact Mode II Fracture Specimen
Authors: Banks-Sills L , Arcan M
Published: December 2008

A compact Mode II fracture specimen together with its loading frame is analyzed and tested. This system is a further development of an earlier circular Mode II fracture specimen presented by the authors. For fatigue precracking in two different loading configurations, formulas relating the Mode I stress intensity factor, applied load, and specimen geometry are developed. In order to determine KIIc from the fracture load, a relationship between KII, the applied load, and specimen/loading frame geometry is obtained. All of these relations are calculated by means of the finite element method.

These formulas are then employed to perform a series of Mode II fracture toughness tests with Perspex (also called Plexiglas or polymethyl methacrylate [PMMA]). The average measured KIIc value was 0.94 MPa√m. The KIc tests were performed with the compact tension specimen, yielding KIc = 1.06 MPa√m; thus KIc/KIIc was found to be 1.127. In addition, crack propagation angles were found to be between 63 and 70°. These results are compared with the maximum tangential stress and maximum tangential principal stress criteria.
Assessment of J-R Curves Obtained from Precracked Charpy Specimens
Authors: Kapp JA , Jolles MI
Published: December 2008

J-R curves were determined for five materials (7075-T651, 2024-T351, HY130, HY80, and A723, Class 1, Grade 4) using precracked Charpy specimens and standard size C(T) and SE(B) specimens. Crack growth in the Charpy specimens was estimated using the “load drop” method of analysis of the load-displacement trace, and crack extension in the C(T) and SE(B) specimens was determined using the electric potential method. The results show that physical crack extension in the larger specimen was not well estimated by the Charpy specimen results. If the crack extension is presented as relative crack growth (as a percentage of the uncracked ligament), however, the agreement between the two widely different specimen sizes is much better, although not exact. Except in the relatively brittle 7075-T651, the J corresponding to 0, 1%, and 2% crack growth was higher in the Charpy specimens than in the larger specimens. This was attributed to the inability of the “load drop” method to determine the exact location of the crack initiation. Although nonconservative, we believe the “load drop” method analysis of precracked Charpy data is adequate for quality control toughness testing, provided it is realized that JIc and J-R curves may be overestimated slightly.
An Investigation of the I and dJ/da Concepts for Ductile Tearing Instability
Authors: Etemad MR , Turner CE
Published: December 2008

Unstable ductile tearing was found in a series of tests on notched bend-bars of HY130 steel tested in a screw-driven machine. R-curves were measured and ductile tearing stability analyzed according to the energy rate, I, and dJ/da tangency concepts. The effect of compliance on the energy rate available and an appropriate estimation of work dissipation rate for the I theory are described. The dJ/da concept is used in both its “exact” form and as originally stated in terms of T, with certain compliance terms modified. Subject to choice of appropriate compliance terms, the experimental behavior is predicted satisfactorily by both I and dJ/da methods, although the restriction of this analysis to a configuration very similar to that on which the R-curve was measured must be recalled.
An Automated Ultrasonic Data Acquisition and Evaluation System
Authors: McGarvey TJ , Murray J , Roller D
Published: December 2008

A computer-based ultrasonic (UT) inspection system has been developed which provides a method for locating and sizing flaws in the near-bore region of steam turbine rotors. Components from various manufacturers were integrated to make up this unique test system.

Shear wave inspections are performed utilizing an expandable test head coupled to a positioner via geared extension bars. The head accepts up to three transducers while the positioner provides the axial indexing and circumferential rotation of the transducers.

A microprocessor is supplied with signal information from a multichannel UT instrument and location information (axial and circumferential for each transducer) from the positioner. All recorded data are transferred from the computer memory to floppy disks, thus maintaining a historical record of all test results.

Upon completion of each UT inspection scan, a color video monitor with graphic display allows for evaluation of test data utilizing several software programs which are presently available. A color printer supplies a hard copy of inspection results.

A visible magnetic particle (MT) examination is performed from the bore to provide additional information on surface and near-surface flaws. This boremag inspection is accomplished using the positioner with extension bars and a miniaturized TV camera with a light source and mirror. The camera outputs to a video recorder and a video monitor.

The UT and MT inspections provide a data base which can be used for evaluating turbine rotor integrity and monitoring flaw propagation. With the addition of new software and a different type positioner, the basic ultrasonic hardware can be used for inspection of brazed joints in sleeved steam generator tubes. Other possible applications of this system (UT on piping, eddy current in tubing, etc.) are discussed.
Development of a Sensor for Real-Time Detection of In-plant Crevice Contaminants
Authors: Carmichael NE , Leverant GR , Hugg SB
Published: December 2008

Most forms of corrosion damage in electric power plants are believed to involve the concentration of corrosive species in critical crevice locations such as between disc keyways and keys. The development of an on-line, real-time sensor capable of detecting the concentration of corrosives in crevices is presented in this paper. The sensor measures the temperature and conductance of fluid films entrapped within the crevice of the sensor. The sensor crevice was designed to entrap contaminants similar to those found in actual crevices and to contain the contaminants for future analysis.

Several sensors were laboratory-tested in aqueous solutions within autoclaves and steam lines. Three sensors were evaluated at an electric power plant. These sensors were hard-wired to a steam extaction line and an autoclave in which stress corrosion cracking tests were being conducted. Although problems were experienced with the materials used in sensor construction, the field evaluation demonstrated real-time collection of conductivity and local temperature data and accumulation of crevice contaminants with subsequent laboratory analysis.
Ultrasonic Velocity Ratio Method for Detecting and Evaluating Hydrogen Attack in Steels
Authors: Watanabe T , Hasegawa Y , Kato K
Published: December 2008

An ultrasonic attenuation technique has been employed in practice to detect hydrogen attack nondestructively. However, it is difficult to evaluate hydrogen attack quantitatively by this technique, because ultrasonic attenuation is influenced by the test conditions and the material itself.

In this paper, a new approach to a quantitative evaluation of hydrogen attack with an ultrasonic velocity technique is described. The longitudinal and shear wave velocities were observed to decrease more than 10% and 7%, respectively, in a steel fully attacked by hydrogen as compared with those in sound steel. This large change in velocity is sufficient to enable the thickness attacked by hydrogen to be predicted, if the wall thickness of material concerned is known.

Moreover, the ratio of shear wave velocity to longitudinal wave velocity is quite promising as a factor for evaluating the thickness attacked by hydrogen, without measuring the thickness of material tested.
Detection of Hydrogen-Assisted Crack Growth by Measurement of Modulus Changes and Acoustic Emission
Authors: Carpenter SH , Armstrong J , Heiple CR
Published: December 2008

An investigation of new techniques to probe and study the initiation of cracks in a hydrogen environment is reported. The techniques investigated are the precise continuous measurement of changes in the elastic modulus and acoustic emission measurements. A decrease in the elastic modulus should be observed as cracks nucleate and grow in a test material. Measurements of changes in the elastic modulus while cathodically charging a number of iron base materials both at zero load and under applied load are also given.

In all cases a decrease in the elastic modulus was observed as a result of cathodic charging with hydrogen. The modulus loss was found to be permanent and could not be restored by heat treatment. Acoustic emission measurement were carried out as miniature pressure vessels were pressurized and subsequently held at pressure. Differences in the acoustic emission were observed for vessels pressurized with hydrogen gas as compared to vessels pressurized with helium. Considerably more acoustic emission was generated in vessels pressurized with hydrogen.
A New Electrochemical Hydrogen Probe
Authors: Yamakawa K , Tsubakino H , Yoshizawa S
Published: December 2008

A new electrochemical hydrogen probe consisting of a thin layer of deposited nickel was developed for use in laboratory and in field tests. The principle of such a probe is based on the formation of nickel oxyhydroxide (NiOOH) which contains a mobile hydrogen. The probe was used to examine the effect of plastic deformation on hydrogen absorption and the relationship between KISCC and hydrogen content, and to monitor hydrogen contents continuously at the carbon dioxide absorption tower and line pipe.
Trouble-Shooting Industrial Corrosion Problems with Electrochemical Testing Techniques
Authors: Liening EL
Published: December 2008

Two case histories illustrate the use of simple electrochemical testing techniques for trouble-shooting corrosion problems in the chemical process industry. Simple electrochemical techniques that are within the capability of the non-electrochemical specialist are seen to be powerful tools for problem-solving. The measurement and interpretation of corrosion potentials, galvanic currents, and polarization curves, in particular, are presented. How these techniques are used by the production-support corrosion engineer and the researcher is seen to differ, because of their differing objectives and constraints. Accordingly, their work must be judged by different criteria.
On-Line Monitoring of the True Corrosion Rate in Problems Related to Power Plants
Authors: Rizzi R , Ronchetti C
Published: December 2008

The know-how gained during corrosion studies performed for several years has enabled the authors' company to design and construct various probes for the measurements of the true corrosion rate in industrial plants. In some cases, for instance, the monitoring of steam condensers and of different circuits in thermal plants has been in operation for some years, now showing good reliability and usefulness.

Further developments have been made for use of the probes even under difficult working conditions, and the experimental results carried out on pilot loops propose such probes as a tool for a wider corrosion rate monitoring of different structural materials in different operating conditions.
Corrosion Rate of Cast Iron and Copper Pipe by Drinkable Water
Authors: Piron DL , Desjardins R , Brière F , Ismael M
Published: December 2008

The corrosion rates of cast iron and copper in drinkable water distribution systems are compared in this investigation. Sixty-one solutions were prepared, of varying concentrations in Cl-, NO-3, SO=4, and with differences in alkalinity, pH, and Langelier index.

Cut from actual pipe, 2070 specimens 4 cm by 3 cm by 0.1 cm (1035 cast iron and 1035 copper) were immersed in the solutions for 3, 6, 9, 12, or 15 days, and their corrosion was determined by weight loss. For both metals, corrosion was more rapid during the first three days.

The cast iron corrosion product contained between 35% and 55% iron. X-ray diffraction revealed the presence of goethite, lepidocracite, and after three days of immersion, amorphous magnetite.

For the same experimental conditions, the copper corrosion rate was significantly smaller than that of ductile cast iron.

The corrosion rate of copper was not found to be affected by the composition of the water. In this investigation, no correlation was found between the Langelier index and the corrosion rate for copper or cast iron. This was true for both negative and positive Langelier index.
Computer-Controlled AC Impedance Measurements for the Determination of Water Penetration of Anticorrosion Coatings
Authors: Kellner JD
Published: December 2008

A computer-controlled system is described for the measurement of the AC impedance spectrum of coated pipe samples in the laboratory. The extent of water penetration into various coatings were compared.

Bode plots were made of the coated pipes until water penetration became excessive. Then Nyquist plots were used to demonstrate the mechanism of water penetration. The data showed that water incorporation into these thick pipeline coatings is into pores and defects rather than a uniform general penetration.

Thus, it is contrary to the observed mechanism of water penetration to calculate a penetrated thickness as recommended in the ASTM Test Method for Water Penetration into Pipeline Coatings (G 9).
Corrosion of Carbon Steel in Concentrated Naoh Solutions: Influence of LIOH Additions
Authors: Belletête M , Vijayan CP , Hechler J-J
Published: December 2008

The present study aims at determining quantitatively the influence of lithium hydroxide (LiOH) as an inhibitor on the corrosion behavior of carbon steel in a 33-weight percent sodium hydroxide (NaOH) solution at temperatures <110°C. This work is conducted as a prelude to further high temperature studies dealing with stress corrosion. Potentiodynamic methods are used in determining the influence of LiOH additions. Cyclic voltammograms indicate gradual variation in the intensities corresponding to certain peaks, depending on the presence or absence of LiOH and on the temperature of the solution. An improvement in corrosion behavior is indicated when LiOH is present at a concentration of 20 g/L. Apparent activation energies are calculated and certain ideas are put forward in order to explain the behavior of carbon steel in NaOH containing LiOH.
A Review of Microbiological and Electrochemical Techniques in the Study of Corrosion Induced by Sulfate-Reducing Bacteria
Authors: Tuovinen OH , Cragnolino G
Published: December 2008

Methods of measuring and evaluating the presence and distribution of sulfate-reducing bacteria are discussed. The microbiological methods are based on cellcounting (enumeration) techniques, microscopic examination, determination of bacterial activity, and immunological detection. Several experimental approaches to these methods are outlined with emphasis on their suitability and limitations in studies of sulfate-reducing bacteria associated with corrosion problems.

Electrochemical methods employed in laboratory studies of corrosion induced by sulfate-reducing bacteria are reviewed, with emphasis on the advantages and limitations of current techniques, such as determination of open circuit potentials, anodic and cathodic polarization curves, polarization resistance measurements, and determination of critical potentials for pitting. The applicability of microbiological and electrochemical techniques to field studies is briefly discussed.
Design Considerations for Occluded Cell Corrosion Monitoring
Authors: Silverman DC , Krisher AS
Published: December 2008

Occluded cell corrosion is a major contributor to unexpected and premature failures. A reliable, on-line instrument to monitor for occluded cell corrosion would generate benefits of a decreased frequency of failures and a more reliable estimation of service life. This paper reviews the thermodynamic and kinetic bases for such a practical monitor to show that the concept is sound. Crevice dimensions, cathode-to-anode area ratio, and defined hydrodynamics—parameters important in the in-plant monitor—are defined in this discussion. Finally, a conceptual model of a proposed in-plant monitor is presented. The dimensions and geometry are derived from the discussion of the theory.
Determination of Field-Ionization Sensitivities for Saturated Hydrocarbons in the Presence of Acetone and Their Application to the Analysis of Shale-Oil Saturates
Authors: Scheppele SE , Grindstaff QG , Grizzle PL
Published: December 2008

Field-ionization relative sensitivities were determined for 18 n-alkanes and 22 cycloalkanes in the presence of acetone at 270 to 300°C. The relative gram sensitivities for n-alkane and n-alkylated cyclohexanes, decalins, and perhydroanthracenes/perhydrophenanthrenes decrease linearily with decreasing reciprocals of their molecular weights. Since the first three correlations result in negative changes in the relative mole sensitivities for these three families with increasing carbon number, alteration in their acetone perturbed ionization necessarily occurs between about C25 and C32. Linear correlations exist between the mole sensitivities for parent cycloalkanes containing either six-membered or six- and five-membered rings relative to cyclohexane and -Z(H;H). The slope of the former correlation is considerably larger than the latter one. These results and a set of assumptions generated the sensitivities required for quantitative analysis of the field-ionization mass spectra (FI/MS) of the 200 to 325, 325 to 425, and >425°C saturates from a hydrotreated shale oil. The agreement in the analytical results obtained by FI/MS, 70-eV electron impact mass spectra (EI/MS) (ASTM Method for Hydrocarbon Types Analysis of Gas-Oil Saturate Fractions by High Ionizing Voltage Mass Spectrometry [D 2786]), and flame-ionization detection gas chromatography (FID/GC) ranges from excellent for the 200 to 325°C saturates to nonexistent for the >425°C fraction. Thus, all three methods require additional developmental research in an attempt to obviate deficiencies and, hence, delineate their ultimate applicability.
Recent CIE Work on Color Difference Evaluation
Authors: Robertson AR
Published: December 2008

Since the 1976 provisional recommendation of the CIELAB and CIELUV uniform color spaces and color difference formulae, a Committee of the Commission Internationale de l'Eclairage (CIE) has continued to work on the problem of color difference evaluation. In 1978 the committee published some guidelines in an effort to stimulate and coordinate research in the area. Following that, a number of studies were undertaken in which color difference ellipsoids were derived from observations of object colors. These studies have measured the effect (or lack of effect) of parameters such as the size of the color difference, the severity of the observer, and the type of dividing line between the samples. Other studies have shown that different relative weights for lightness, chroma, and hue indices may be needed for different viewing conditions and for different types of sample. Work planned for the next four years includes an attempt to assemble a single representative set of data with which color difference formulae can be tested.
Measuring the Appearance of Retroreflectors by Application-Oriented Goniophotometry
Authors: Johnson NL
Published: December 2008

Evaluating the appearance of retroreflectors involves the application of the basic principles of appearance measurement. It is typical of many appearance measurement problems in that it involves a source (or sources) of illumination, a viewer, and an object or surface of concern. The objective is a numerical description of the appearance properties of the material. For such descriptions, the measurement geometry must be established, the spectral conditions considered, and meaningful appearance related quantities agreed upon.

In the measurement technique described here, computers are used to control the instrumentation for geometric and spectral analysis while simultaneously calculating appearance related quantities, along an appropriate application parameter. A shoulder mounted retroreflective road sign is the example considered, and the application parameter is the distance from vehicle to sign. Local viewing and illuminating geometry are translated into a laboratory measurement coordinate system. These transformations are made at distances corresponding to the incremental motion of a vehicle along the roadway. From these application-oriented measurements, intrinsic photometric results are calculated and displayed in terms of quantities such as coefficient of retroreflection. Once the material characteristics are measured, along the application parameter, additional analysis using the actual illuminating source can be completed. In the case of the retroreflector, the luminance in the direction of the viewer is an important result. Evaluation based on practical viewing conditions provides a useful insight into appearance without the necessity of completely describing the spectraogoniophotometric properties of the retroreflector.
Specifying the Appearance of Escalator Treads: How to Minimize the Disorientation Effect
Authors: Cohn TE
Published: December 2008

Escalator passengers sometimes experience a feeling of disorientation or dizziness while boarding or riding the machine. Prior work has shown that this perception may be due to a visual depth illusion caused by the appearance of the escalator tread. Measurements confirm that the escalator tread surface is a highly periodic visual stimulus exhibiting unusually high contrast as well as a spatial frequency matched to the preferences of the visual nervous system. Means of minimizing the depth illusion are explored. These center on disrupting the periodic structures of the tread surface. Expressions intended to serve as candidates for figure of merit for the tread appearance are developed. These take into account some properties of the visual nervous system including the decline with eccentricity of visual acuity and the bandpass character of spatial detail processing under light adapted conditions.
Visual Color Technology Development for Industrial Applications
Authors: DeGroff JT
Published: December 2008

There has been a need for a visual method of generating a color without preparing a sample standard or finished product. This styling and reference capability is required to generate new colors and review their visual appearance during the development of new products or restyling old lines. In the majority of visual approaches, a color chip or other reference has been used as a guide, which must then be matched with colored materials on a manual basis. Even with the utilization of an automated computer color system, the visual appearance of many materials cannot be fully duplicated until the actual product materials are available.

Applied Color Systems' staff approached the question, “Is it possible to create a device that can simulate the finished product color and appearance that can be duplicated in the final product?” several years ago with a technology review and came to the conclusion that a mechanical/electrical approach could supply many of the answers to solve this need. As part of the technology review, we studied projection systems, video graphics, and the integration of spinning disks. Of all of the currently available technologies, we found that only the spinning disk based on the Maxwell technique solves both the color and appearance problems and gives reproducible results that can generate predictable colorant formulations.

The device developed from the basic Maxwell disk concept is a solid state fully integrated system that creates visual color simulations that duplicated a range of typical industrial product finishes. It is apparent that many exciting new things can be accomplished with such a device. By adding visual modifications to the disks, the operator can visualize various loadings of white or create a metallic “look” to simulate metal loadings of paint or ink finishes. He can then take the data output from this device and convert them by computer into colorant formulas on a fully automated basis. This same data can be used to communicate color data from one location to another and be able to see the actual color in the second location.

Industry may also be able to use such a device as a merchandising aid to help the customer to visualize the finished product color, whether it be on an industrial product surface, a contractor's building, or an interior decorating scheme.

Based on performance in a number of industrial installations, we now feel confident that the Visual Color System can be an important aid to industry in the styling, communications, and merchandising of colored products. The device has the potential to open up new development areas in color technology to allow the manufacturer to have better control of color specification and a visual understanding of the color component of his product.
A Device for the Controlled Production and Placement of Individual Droplets
Authors: Young BW
Published: December 2008

A novel device has been designed and successfully used to produce, and accurately place, individual droplets of pesticidal formulations onto target surfaces. The device is based on the technology of impulse jet “drop on demand” printers, and can produce a single droplet when required, or can run at a low frequency (say, 1 to 10 Hz) to produce a stream of identical droplets. Droplets over a wide size range have been produced, for a range of aqueous and nonaqueous formulations. The directional stability of the ejected droplets enables accurate placement of each droplet onto specific sites.

The device has been used to study the impaction and retention of individual droplets on leaf surfaces and on commonly used targets, such as Kromokote cards. It has also been used to apply controlled volumes of tracer formulations in order to develop recovery techniques for spray distribution studies.

The device has potential for use in many areas where the controlled production of small volumes of liquids is required; and because it is a pulsed device it offers the exciting possibilities of computer control and triggering.
Electrostatic Spraying of Oil-Based Agricultural Products
Authors: Simmons HC , Kelly AJ
Published: December 2008

There is burgeoning interest in the use of oil based, high-persistence media for the low volume application of agricultural chemicals. Although electrostatic atomizers appear to offer the most appropriate means for the effective application of these carriers, it has heretofore been necessary to modify the formulations to permit operation with existing devices. This has entailed altering the intrinsically high resistivity of these fluids (0.1 cu) to the 104 to 106 cu range where existing electrostatic atomizers can function.

A prototype electrostatic atomizer which is capable of spraying unaltered oil-based fluids is described. This device uses direct charge injection to provide unipolarly charged droplet sprays of a wide range of fluids independent of their physical properties. Atomization is purely electrostatic with no auxiliary means such as spinning disks, air blast, or swirl assist being required for droplet formation. A compact device (1 by 2 by 1 in.) is capable of providing flow rates from 0.1 gal/h upwards with constant output charge density. Operation is at about 10 kV and several microamperes for a total electrical input (exclusive of fluid delivery power) of a few tens of milliwatts. This makes the unit compatible with battery operated hand-held as well as power limited mobile applications.

Operating characteristics and droplet size distribution data are presented for a representative test oil. It is shown that droplet size distributions that are considerably more monodisperse than those obtained from conventional atomizers can be readily achieved. This feature, along with the intrinsic “wrap-around” capability of the charged droplets, is a particularly significant attribute for effective application.
Development of Drop Size-Frequency Analysis of Sprays Used for Pesticide Application
Authors: Akesson NB , Yates WE
Published: December 2008

The development of automated spray drop analyzers has moved from early types using automation only to scan photographic negatives of drops caught on a solid or liquid substrate to in situ type devices capable of sampling a spray cloud in the air. The ruby laser has added the latest development, providing for broad drop size spectrum analysis with both imaging and light scatter techniques. Data taken with a ruby laser instrument with selected pesticide spray atomizers indicate the effects on drop size of (1) increasing atomizer throughput, which increases drop size, and (2) varying angle of spray discharge to airstream for fan and hollow cone type sprays. Increasing the spray angle decreases the drop size. Data on a rotary atomizer at one peripheral velocity and one throughput are also shown.
Progress in Droplet Sizing Instruments and Procedures
Authors: Tate RW
Published: December 2008

For many years, coated slides, sensitized paper and cards, collection cells, impaction devices, and high-speed photographs were utilized to estimate the size of droplets in agricultural sprays. Developments in laser optics, solid-state imaging, and integrated circuits have now led to a new generation of sophisticated instruments for sizing liquid particles. Based on holography, light scattering, interferometry, and imaging, and linked with computerized data reduction systems, these instruments are generally capable of rapid, nonintrusive measurements. Researchers, however, must still cope with such considerations as calibration, data repeatability, and accuracy. Erratic data and disagreement between instruments are persistent problems that have surfaced during informal comparisons and in organized round robins. These difficulties do not necessarily indicate faulty equipment. Most instruments have inherent limitations that may involve permissible ranges of particle size, velocity, and flux. Sampling and data reduction procedures also affect results. Droplet size analysis has not yet become truly automatic. Experience and judgment are necessary ingredients in the quest for valid data.
Laser Droplet Interferometry Approach to Spray Drop Size Analysis
Authors: Kennedy JB
Published: December 2008

With the advent of modeling computer programs which can handle in a timely fashion the elliptical Navier-Stokes equations and the growing demand for more knowledge about the design of injectors, a need has arisen for detailed or point measurements of the air velocity and droplet size and velocity downstream of injectors. The air velocity can be readily measured by seeding the airflow and using a standard nonintrusive laser doppler velocimetry (LDV) system. The laser droplet interferometry approach is a promising technique that is nonintrusive and has the potential of simultaneously measuring the droplet size and velocity from a single point measurement. Two laser droplet interferometry techniques are currently being developed. One of these techniques is the Imax system being developed at Spectron Development Laboratory, Inc., by Dr. Cecil Hess; the other system is the Phase-Doppler technique being developed at Aerometrics, Inc., by Dr. Will Bachalo. The principles behind these systems and some typical data are presented in this paper.
Practical Use of the PMS Spray Analyzer for Pesticide Application Research
Authors: Huddleston EW , Sanderson R , Ross J
Published: December 2008

A Particle Measuring Systems (PMS) OAP-2D-GA2 spray analyzer was found to be an effective tool for comparing the droplet spectra from three similar sprayers. Field tests using soda straws as deposition targets showed that the sprayer that produced the smallest volume median diameter gave the most uniform and widest swath when used in a 4.5 m/s wind. Efficacy trails against range caterpillar confirmed the PMS and field test results. This research resulted in a practical, economical ground-based application method for range caterpillar control.
Use of a Laser Imaging System for Agricultural Spray Analysis
Authors: Bode LE , Jahn BC , Derksen RC
Published: December 2008

The PMS laser imaging system has the capability to rapidly determine the droplet spectrum from agricultural spray nozzles. The system hardware is reliable and accurate but correct sampling techniques are required to obtain representative data for each nozzle setting. Probe aperture width, sampling method and location, droplet density and velocity all affect the results obtained. Used properly, the system will increase our knowledge of droplet size spectrums so that pesticide application efficiency can be improved.
Turbine Lubricant Oxidation: Testing, Experience, and Prediction
Authors: Smith AN
Published: December 2008

Early in the 1970s failure of conventional turbine lubricating oil in modern heavy-duty gas turbines fostered the development of high-temperature mineral oils, the search for appropriate more severe oxidation tests, and efforts to relate the experience to tests and analysis. In parallel with this lubricant effort, bearing and bearing seal developments were undertaken.

The oxidation testing results have evolved into characteristic curves. Operating experience can be related to the heat source temperature. On the basis of the oil characteristic curves and the exposure temperatures, life predictions are made.

In general, the characteristic curves and the operating experience show that the rate of the reaction doubles for every 10°C increase in temperature.
Oxidative Degradation Mechanisms of Lubricants
Authors: Hsu SM , Ku CS , Pei PT
Published: December 2008

Lubricant degradation under in-service conditions can be often traced to oxidation. Environmental effects under in-service conditions are often recognized to affect the oxidation pathways of lubricants. In this study, environmental factors such as metal catalysts, fuel components, and oxides of nitrogen are studied systematically in a simple oxidation test. The test consists of bubbling air into the oil sample at 175°C. Periodic samples were withdrawn and analyzed. Results show that the environmental factors not only have significant influence on the rate of oxidation, but also on the oxidation pathway of how lubricants degrade. The acid number increase was found to be an important parameter in monitoring the lubricant degradation mechanisms.
Infrared Spectroscopy as a Tool for Monitoring Oil Degradation
Authors: Coates JP , Setti LC
Published: December 2008

Oxidative and thermal degradation of lubricating oils are complex processes. While the fundamental chain reaction mechanisms are known, the actual chemistry of a formulation involving several additives still remains a gray area. An understanding of some of the additive interactions and their degradation pathways will ultimately lead to a more scientific approach to formulation optimization for a given application. Current methodology involves laboratory bench tests as a screening mechanism before the more expensive mechanical tests are used for the evaluation of a final lubricant formulation. This is particularly the case for automotive and gas turbine lubricants. The chemistry linking the bench test and the mechanical tests to the oil formulation are rarely considered.

This paper will illustrate how modern infrared spectroscopy can be used to monitor lubricant degradation. Also, it will demonstrate by simple applications, that the technique has the potential of providing much of the information required to follow the chemical reactions that are involved.
The Use of Zirconium in Nitric Environment Corrosion Studies
Authors: Leduc M , Duigou AL , Pelras M
Published: December 2008

Different corrosion studies, performed on zirconium and its alloys in nitric acid environment, are described. The main topics are as follows: (1) behavior of the different grades of zirconium, (2) influence of metallurgical state, environment characteristics and some practical uses, and (3) resistance to stress corrosion cracking. In most cases, the results were satisfactory and zirconium showed an outstanding behavior in comparison with stainless steels.
Zirconium-Steel Bimetallic Tubing for Improved Sour Gas Corrosion Resistance in Oil and Gas Wells
Authors: Wang CT , Hardwick R
Published: December 2008

Bimetallic tubing with corrosion resistant liner material has been developed for sour gas well applications where conventional carbon steel tubes have serious corrosion problems.

The present project deals with the tubing consisting of 4130 steel outer wall and zirconium liner. The manufacturing process starts with an assembled billet. To enhance the bonding between layers, either an interlayer copper or an explosive bonding technique may be used for the billet preparation. The billet is hot extruded and then tube reduced to the final size. The final tube can be heat treated and water quenched to meet the requirements of the oil field tubular products. Tests show that the bonding between layers achieved by explosive bonding and extrusion is excellent.

A section of the tube with zirconium liner exposed to a brine solution saturated with hydrogen sulfide (H2S) under a pressure of 1.72 MPa (250 psi) and a temperature of 493 K for 1368 h showed no sign of corrosion attack by the medium. Other corrosion and stress corrosion tests for zirconium also showed excellent results.
Application and Process Metallurgical Aspects of Niobium, Tantalum, and Hafnium
Authors: Krishnan TS , Gupta CK
Published: December 2008

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

In the Bhabha Atomic Research Centre, a considerable amount of development work has been carried out on niobium, tantalum, hafnium, and other reactive and refractory metals, and flow sheets have been evolved for the production of metals, some of their carbides, alloys, and ferro-alloys. Based on these processes, indigenous production facilities have also been set up. The paper briefly presents the work that has been carried out on the production technology of the reactive and refractory groups of metals with particular reference to niobium, tantalum, and hafnium.
Design of Soil Sampling Programs: Statistical Considerations
Authors: Flatman GT
Published: December 2008

This paper identifies the critical problems of soil sampling for pollution monitoring and explains the solutions provided by new advances in spatial statistics such as Kriging. The U.S. EPA at the Environmental Monitoring Systems Laboratory, Las Vegas, is applying new types of spatial statistics to the chronic problems of pollution plume monitoring and contouring. Firstly, the most common soil sampling problem is the failure to recognize and utilize autocorrelation in space and/or time of the variable in question. Such correlation variables require a systematic rather than a random sampling design, and a spatial analysis by contouring rather than a t-test. This problem can be solved by the use of Kriging. Secondly, chemical analyses of pollution samples often give many readings below detection limit with a few relatively high readings indicating a non-normal, truncated, positively skewed distribution. Estimates or tests assuming normal theory are imprecise for such data, but nonparametric spatial statistics are more appropriate. Thirdly, data may be from different monitoring techniques or different chemical analyses, causing heteroprecision. Such data require an analysis such as “soft-data” Kriging that accounts for the precision of each datum in the analysis. Finally, if remediation decisions are to be based on the data, the probability of misjudging “clean areas to be dirty” or “dirty areas to be clean” must be calculable. Probability Kriging gives such probabilities. This paper discusses these new forms of spatial analysis as they apply to the recurring problems of pollution monitoring.
The Role of the Environmental Protection Agency's Contract Laboratory Program in Analytical Methods Evaluation and Validation
Authors: Kovell SP
Published: December 2008

The Environmental Protection Agency's Contract Laboratory Program (CLP) offers a unique opportunity to evaluate and validate new analytical methodologies under real-world conditions, utilizing the very laboratory community that will ultimately be using the methods. As a result of the established infrastructure and the laboratory resources available, the CLP has a viable system to test new methods with consistency and discipline. The CLP has established the Routine Analytical Services (RAS) and Special Analytical Services (SAS) programs which are both instrumental in methods testing and validation. The RAS program generates a large laboratory performance data base which is directly applicable to the evaluation of new analytical methods. The potential for utilizing the CLP for evaluating and validating new analytical methodologies is proven and should be utilized.
Quality Assurance Support for the Superfund Contract Laboratory Program
Authors: Moore JM , Pearson JG
Published: December 2008

The Environmental Protection Agency's Environmental Monitoring Systems Laboratory-Las Vegas (EMSL-LV) functions as the quality assurance (QA) arm of the Contract Laboratory Program (CLP). The EMSL-LV provides standards and quality assurance materials, maintains a quality assurance data base, and conducts data audits, performance evaluation studies, and on-site laboratory evaluations. In addition, the EMSL-LV is very actively involved in evaluating laboratory and method performance. Due to its unique position of receiving all of the data from all of the CLP laboratories, combined with its charge of quality assurance oversight, EMSL-LV is most able to assess intra- and inter-laboratory performance as well as programwide method performance. This paper describes the EMSL-LV QA program for the CLP as of October 1985.
Inorganic Analytical Methods — General Description and Quality Control Considerations
Authors: White DK
Published: December 2008

The Environmental Protection Agency's (EPA) Contract Laboratory Program (CLP) provides a variety of state-of-the-art chemical analysis services in support of the Superfund program. The CLP utilizes inductively coupled plasma (ICP), flame atomic absorption (FAA), graphite furnace atomic absorption (GFAA), and cold vapor techniques to analyze water and soil/sediment samples for inorganic priority pollutant constituents. The data generated through the sample analyses is used by EPA to determine the existence and potential threat posed to the public and the environment by identified hazardous waste sites. The extensive quality assurance/quality control (QA/QC) system ensures that data generated by the CLP laboratories is of known quality and is legally defensible in Agency enforcement cases.