bluuebunny/crossref_metadata_2025 huggingface dataset:
Atmospheric Corrosion of the Suspension Cables on the Williamsburg Bridge
Authors: Eiselstein LE , Caligiuri RD
Published: December 2008

The Williamsburg Suspension Bridge across the East River in New York City was opened to traffic in 1903. The four main support cables are composed of 7696 high carbon steel wires spun into 470-mm diameter cables. These wires were ungalvanized but given a protective organic coating when installed. The cables were inspected in 1980 and found to have undergone a significant amount of atmospheric corrosion. In 1982, wire samples up to 91 m in length were removed from the cables and the extent of atmospheric corrosion damage was evaluated. Mechanical properties experiments on corroded and uncorroded wires indicate that the atmospheric induced corrosion damage has degraded the load bearing capacity of the cable. An accelerated cyclic wetting/drying atmospheric corrosion test was used to estimate the current rate of corrosion induced damage. Based on these observations, it was concluded that the acidity and the chloride ion content in the New York City area precipitation, plus the graphite in the original organic coating, are the principal factors contributing to the atmospheric corrosion of the cables. Furthermore, the estimated current rate of corrosion confirms that some sort of cable rehabilitation or replacement is necessary.
Environmental Degradation of Telecommunication Hardware
Authors: Lee TSF , Healey N , Trumble WP
Published: December 2008

This paper is a survey of the corrosion problems encountered in Bell Canada's telecommunication hardware. Specifically, the environmental attack on the outdoor metallic equipment will be addressed. These metallic parts include outdoor connectors, guy strands, lashing wires, guy hooks, cabinets, and manhole equipment. To be presented are the results of material analyses, failure analyses, field testing, and accelerated laboratory testing, which include a number of investigative programs undertaken in the previous years.
Computer Techniques in Corrosion Protection
Authors: Průšek J
Published: December 2008

The development of a problem oriented corrosion expert system (CES) is described. The CES has the following aims: (1) compilation of corrosion data files from data obtained by experimental activities or from analyses of practical results, (2) analysis of corrosion problems (determination of environmental aggressivity, degradation mechanisms, and corrosion kinetics) with the use of corrosion data bases and generalized theoretical knowledge, (3) optimizing the selection of technology for the protection of engineering plant, machines, and products from corrosion, and (4) economic analysis of the individual corrosion protections suggested.

Corrosion technologists and designers can utilize CIS to (1) file the results of corrosion research for subsequent application in corrosion analysis and evaluations and (2) objectivize, upgrade, and speed up the designing of corrosion protection including its economic evaluation.

The structure of the software has been devised for the interactive solution of problems. A dialogue of the user and the computer permits protection design optimizing.
Environmental Factors Affecting the Corrosion of Galvanized Steel
Authors: Haynie FH
Published: December 2008

Galvanized steel samples are exposed for periods of up to 30 months at nine air monitoring sites in the St. Louis, MO area. Climatic and air quality data are recorded during the exposure periods and subjected to a rigorous evaluation to eliminate recording errors and to estimate missing values. Weight loss is used as the measure of zinc corrosion on the galvanized steel. The corrosion rate is evaluated with respect to (1) fluxes of pollutants (sulfur oxides, nitrogen oxides, oxidants, and particles) to the galvanized steel during both wet and dry periods, (2) temperature, and (3) amount of rainfall at Lambert Field (airport). Different definitions of when the galvanized steel was wet are evaluated to determine the most likely “critical relative humidity.” A theoretical model of film buildup and dissolution is developed to explain how factors affect corrosion rates. Nonlinear and linear multiple regression techniques are used to determine the statistical significance of each factor.
Atmospheric Corrosion in Maritime Industrial Atmospheres: Laboratory Research
Authors: Knotková D , Bartoň B , Van Tu B
Published: December 2008

An extensive testing program was carried out for studying the corrosion of steel and zinc in environments intended to model atmospheres containing SO2, SO42−, sodium chloride (NaCl), and seawater. Both gaseous and droplet types of the corrosion stimulators were introduced into the system together, alternatively, or subsequently in graduated doses. The corrosion tests were performed in a cyclic mode. The weight losses, composition of corrosion products, and radiochemical detection of sulfates have been followed. Parallel stimulation of the steel and zinc atmospheric corrosion by the Cl− and SO42− ions cannot be described by a simple relation. Further components of the reaction system participate in the control of the corrosion kinetics.
The Chemistry of Precipitation: Perspectives on Potential Impacts on the Corrosion of Metals
Authors: Graedel TE
Published: December 2008

The corrosion effects of acid deposition can be assessed properly only if the frequencies of occurrence of different forms of precipitation are specified and if the chemical constitutents and reactions in precipitation are understood. Knowledge of precipitation chemistry is increasing at a rapid rate, and it is therefore useful to summarize the present understanding about the corrosive constituents that occur in precipitation, their typical concentrations, their temporal variability, and their probable long-term trends. Such information is given in this paper for acidity, sulfate, nitrate, chloride, ammonium, and organic acids in rain, fog, and dew.
ASTM Committee E-35 on Pesticides: Past, Present, and Future
Authors: Butler BJ
Published: December 2008

Since its organization in 1973, ASTM Committee E-35 on Pesticides and its 200 to 350 members in 8 to 11 technical subcommittees have produced 64 standards and are drafting many more. Thirty-eight of these standards are test methods, many of which deal with pesticide efficacy. Committee E-35 membership in March 1986 included 143 voters and 67 non-voters. Sixty-six of the voters were producers. In August 1986 there were 221 members: 139 from industry, 21 from U.S. government agencies, 3 from state governments, 16 from universities, and 34 from laboratories and consultants. Subcommittee E35.22 has produced ten standards on pesticide formulation and application and is drafting more. Several successful symposia have been held and more are planned.
Introduction to Session on Closed Mixing, Handling, and Application Systems
Authors: Akesson NB
Published: December 2008

The techniques for closed transfer, mixing, and applying of agricultural chemicals did not originate with agricultural needs, but, because of their large number of users and diverse uses, agricultural closed system problems seem to have been more than usually difficult to resolve. Firstly, there is still considerable disregard for the toxic nature of pesticide chemicals by those who use them, either in agriculture or industry or for home gardening. Because they can be purchased and used with little or no restriction or training, the user tends to treat pesticide chemicals as innocuous materials rather than the toxic poisons that many of them are. But acute toxicity is not the only difficulty with pesticides. Skin, eye, and breathing problems can be initiated or exacerbated by these products. Complaints frequently arise from those who are hypersensitive to the very smell of some pesticides, and allergic reactions are no doubt a part of the high reported illness rate, particularly in regard to contact with treated crops as a deposited residue.
Principles of Closed Systems for Handling of Agricultural Pesticides
Authors: Brazelton RW , Akesson NB
Published: December 2008

Closed transfer of pesticide chemicals from the shipping container to a closed mixing tank and thence to the application machine is but one part of a long range program to protect and improve on the health and safety of workers who handle and apply pesticides. Admittedly the task of maximizing safety in the use of pesticides is far from accomplished, but no one can deny the necessity for moving as quickly and expeditiously as possible toward improvement in this troubled area of farm worker safety.

The use of closed systems has reduced the number of illnesses of mixer/loader personnel. Environmental contamination is also discussed.
Development of Devices Designed to Increase Safety During Field Handling of Pesticides
Authors: Anderson DL
Published: December 2008

Since the 1940s substantial changes have occurred in the use of agricultural pesticides. A variety of new chemicals have been put into use, and the total volume of pesticides applied has increased. Concern for the safe handling of many of these chemicals has intensified as acute illnesses have resulted from handling exposure. Additionally, society's increasing concern with the latent effects of human exposure to chemicals is reinforcing argument for a “minimum exposure” approach to all pesticide handling and has heightened awareness of the logic of limiting environmental pesticide contamination.

This paper discusses the development of devices designed to increase safety during field handling of pesticides. A list of application crew potential pesticide exposure is given.
Spray Drift Deposits from Low Volume Application Using Oil and Water Carriers
Authors: Bode LE , Zain SBM
Published: December 2008

Twelve direct drift comparisons were made from four atomizers using soybean oil and water as the spray carrier. Downwind drift deposits from the rotary atomizer and air-assist nozzles depended on operating conditions. The use of oil for application of chemicals provided little difference in drift reduction as compared to water. Oil has a nonevaporative character compared to water and so deposited higher amounts and drifted further downwind. With conventional twin-orifice and flat fan nozzles oil drifted further downwind than water. Comparing nozzle types, low volume applicators showed more downwind drift than conventional nozzles.
Role of Formulation Ingredients and Physical Properties on Droplet Size Spectra, Deposition, and Persistence of Aerially Sprayed Aminocarb and Mexacarbate in Forest Litter and Soil Samples
Authors: Sundaram KMS , Sundaram A
Published: December 2008

Experimental observations made in five aerial spray trials on the inter-relationships between formulation ingredients, physical properties, droplet size spectra, deposit concentration, litter and soil residues, and persistence characteristics of aminocarb and mexacarbate are described. Spray was applied over conifer forests in New Brunswick, using a Cessna 188 aircraft and Micronair® atomizers. Droplets were sampled at ground level using Kromekote® cards. Deposits of the active ingredients (AI) were collected on glass plates. The physical properties measured were relative viscosity, surface tension, volatility, and viscosity-shear rate relationship; of these, relative viscosity and volatility played significant roles on droplet size spectra and deposition patterns of the sprays. The aqueous formulations of the two insecticides were the least viscous and most volatile. They provided the smallest droplets and lowest droplets/cm2, AI deposits on glass plates, and litter and soil residues; they also had shorter persistence than the oil-based formulations. As the relative viscosity of the formulations increased, their volatility decreased gradually, and there was a progressive increase in droplet sizes, droplets/cm2, deposits of AI, and litter and soil residues. The heavy-oil-based, non-volatile formulation of aminocarb showed slight deviation from this trend with respect to droplet sizes, but the AI deposits and litter and soil residues were still the highest for this formulation, which persisted for a relatively longer period of time than all other formulations. However, none of the formulations caused any undue persistence of the residues in soil, since the levels reached below the detection limit (4 ppb) within five days after treatment.
Sources of Error in Estimating Efficacy of a Microbial Pesticide Against Aquatic Pests
Authors: Vorgetts J
Published: December 2008

Protocols currently used for estimating the amount of toxin present in formulations of Bacillus thuringiensis var. israelensis (BTI) rely on data from acute toxicity bioassays. While the standard protocol proposed for use in the United States is similar to that used elsewhere, they do conflict in certain respects; a major deficiency of both is that some methods in each have not been described in sufficient detail. These problems can be resolved through the ASTM process. An assessment of the present status of methods for estimating toxin content of BTI formulations is provided as a preliminary step in developing a new standard. Emphasis is placed on (1) defining terms used in describing procedures and interpreting results; (2) reviewing some of the physical, biochemical, and biological characteristics of the bacterium and the toxin it produces, which are important in influencing results observed in toxicity bioassays; (3) outlining the limitations of a bioassay method for estimating the amount of toxin in formulations; and (4) outlining research needs for the development of a standard that eliminates the deficiencies of present protocols.
Comparison of Results from ASTM Steel Ball Test (E 728) and Attrition in a Granular Applicator
Authors: Gandrud DE , Skoglund JH
Published: December 2008

ASTM E 728 (also known as the ASTM Steel Ball Test) is the standard method for determining resistance to attrition of granular materials. To find out how the test compares to in-field use, inert clay granules were tested using ASTM E 728 plus three different granular applicators. The ASTM E 728 test produced a lower percent resistance to attrition than any of the three applicator models tested. There was little difference in attrition of the clay granules through any of the three different applicator models.
Dry Etching Techniques for MMIC Fabrication on GaAs
Authors: Bhardwaj JK , Kiermasz A , Stephens MA , Harrington SJ , McQuarrie AD
Published: December 2008

During the fabrication of a GaAs monolithic microwave integrated circuit, there are a number of steps which necessitate the etching of GaAs, namely; mesa etching (for device isolation), gate recessing (to control the saturation current levels), substrate thinning for (transmission line impedance control), through substrate via holes (to reduce interconnection inductances) and scribe-line etching (for yield enhancement). Reproducible dry etch processes have been developed for these steps. However, the diversity of the process constraints imposed by these fabrication steps has led to a number of process operation regimes: for example, resulting in average etch rates ranging from less than 1000Å/min up to 10u/min for 2″ GaAs substrates. The process details are discussed with particular emphasis on the rate limiting steps and the factors governing the reactive gas/surface reaction rates.
The Calibration and Reproducibility of Oxygen Concentration in Silicon Measurements using Sims Characterization Technique
Authors: Goldstein M , Makovsky J
Published: December 2008

A “Load Line Calibration” (LLC) methodology for [0] in silicon determinations by SIMS is introduced. The LLC uses two (or more) p- silicon dice characterized by FTIR as calibration standards that are incorporated into each load of analytical samples. Repeated measurement of p- control samples with an [0] = 27.7 ppma [1] shows that with a two-point-LLC methodology the “load to load” relative error is 2.6% (σ = 0.7 ppma). Measurement results are presented and compared with those obtained by other calibration methodologies. The results have been obtained under experimental conditions that are adaptable for large scale production of controlled oxygen n+ and p+ silicon substates.
Defect, Dopant, and Device Modification using Si(Ge,B) Epitaxy
Authors: Rozgonyi GA , Kola RR , Bean KE , Lindberg K
Published: December 2008

In order to eliminate strain and dislocation generation in heavily boron-doped epitaxial silicon films, co-doping with germanium, a strain counterbalancing element with a larger covalent radius has been utilized. By adjusting the ratios of germane and diborane in a dichlorosilane/hydrogen CVD reactor we can sequentially achieve extrinsic gettering (XG) using controlled introduction of interfacial misfit dislocations with Si(Ge), as well as buried, highly conducting Si(Ge,B) layers which are strain-free and lattice matched to the silicon substrate. It is now possible to perform “Defect Engineering” by strategically positioning singly, or in tandem, either XG or co-doped Si(Ge,B) layers. The p++ layers act as recombination zones or buried field plates to suit the needs of MOS latch-up control, high speed and radiation hard devices, as well as providing defect free p++ etch stops for thin membranes and three-dimensional silicon structures. A variety of these epitaxial structures have been characterized using chemical etching and optical microscopy, X-ray topography and rocking curves, cross-section TEM, SEM/EBIC, SIMS, RBS and Spreading Resistance Profiling. An additional defect engineering program has been initiated in which individual misfit dislocations have been exposed and positioned under oxide mesas by anisotropically etching V-grooves in Si(Ge) XG samples. These structures will be used to examine the basic electrical properties of clean and decorated dislocations. More exotic applications for the creation of electrically useful misfit dislocations as active components in simple devices are being explored.
Effect of Pre- and Post-Epitaxial Annealing on Oxygen Precipitation and Internal Gettering in N/N+(100) Epitaxial Wafers
Authors: Wijaranakula W , Shimada S , Mollenkopf H , Matlock JH , Stuber M
Published: December 2008

Oxygen precipitation in silicon heavily-doped with antimony, particularly at the concentration range higher than 7×1017 atoms/cm3, is known to be severely suppressed because of the doping concentration effect. This results in a reduction in internal gettering (IG) efficiency in the N/N+ epitaxial wafers. In this work, substrate wafers heavily-doped with antimony were pre-annealed prior to the epitaxial deposition process. Post-epitaxial annealing was used for enhancing precipitation in asdeposited epitaxial wafers. The results indicate that both pre- and post-epitaxial annealing can improve oxygen precipitation and IG efficiency. The relationship between oxide breakdown, generation lifetime and bulk defect density is observed.
Electrical Characterization of Electrically Active Surface Contaminants by Epitaxial Encapsulation
Authors: Derheimer A , Takamizawa S , Matlock JH , Mollenkopf H
Published: December 2008

Electrically active contaminants have been successfully detected on the surface of substrates using an epitaxial layer for encapsulation. P-type <100> wafers were deliberately contaminated with phosphorus and aluminum. The substrates were then subjected to a modified epitaxial growth cycle to preserve the contaminant on the surface High frequency C-V dopant profiles were performed, and electrically active contaminants were detected.
Formulation of Pesticide Microemulsions
Authors: Skelton PR , Munk BH , Collins HM
Published: December 2008

In an attempt to investigate alternative pesticide delivery systems, a three phase approach for the formulation of pesticide microemulsions was developed. Also described are typical surfactants and solvents that can be used in this formulation work. In addition, an explanation of the use of ternary phase diagrams is included to assist the formulator. The development of a 0.5% Chlorpyrifos pesticide microemulsion is described.
An Overview — Solvents for Agricultural Chemicals
Authors: Krenek MR , Rohde WH
Published: December 2008

Solvents and petroleum oils have been used in agricultural chemicals for over one hundred years, and this paper presents an overview of the solvents and oils typically used in ag chem today. It includes discussion on solvent and oil applications, classifications, types available, compositions and physical properties. Pesticidal efficacy effects and other technical considerations for choosing solvents and oils are also reviewed.
Effect of Formulation, Droplet Size, and Spatial Distribution on Dose Transfer of Pesticides
Authors: Hall FR
Published: December 2008

Spray application is a complex and dynamic process involving many interdependent components. Improvements in pesticide use efficiency will require a more intensive study of the physical and physiochemical parameters controlling droplet dynamics, deposition on defined targets and biological response. The biological effect depends on the toxicological properties of the active ingredient (AI), its formulation, the concentration and pattern of the dose at the point of action. Changes in formulation of a pesticide may result in significant changes in pest response to and hence transfer of a toxin. Encapsulation of insecticides showed significant changes in avoidance/irritant reactions by certain pests vs that recorded for standard formulations. Droplet size also affected the performance of materials tested. Separation of drop (and particle) size, concentration, and formulation effects can be useful in understanding toxin activity and developing accurate parameters for specific targets and crop protection agents.
Effect of Interaction Between Nozzle Orientation and Crop Canopy Architecture Upon Distribution of Charged and Uncharged Spray Droplets
Authors: Adams AJ , Hall FR , Reichard DL
Published: December 2008

The distribution of spray deposits, applied with an experimental air-atomizing nozzle (ENS, Parker Hannifin Corp.) was examined on cabbage, corn, soybean, and chrysanthemum plants. Very small droplets (Dv0.5∼20 um), of a water + surfactant + fluorescent tracer mixture, were produced by the nozzle which could operate in either an electrostatically charged or an uncharged mode. A fluorometric method was developed to analyze adaxial and abaxial deposits separately with a fluorometer. Comparing microscopic and image analysis counts of fluorescent spots (“droplets”) revealed that the latter technique detected less than 1/3 of the droplets present, while the quantitative fluorometer measurements showed no correlation with qualitative data on droplet density. Charging the spray produced consistently greater deposits than in the corresponding uncharged treatments. Penetration through the foliage was excellent on all crops. Abaxial deposits were much greater on corn than on the other crops with “horizontal” foliage. In some experiments, considerable “rebound” of the air-flow was observed and droplets carried upwards were possibly responsible for the higher abaxial deposits on cabbage and soybean compared to chrysanthemum where the greater foliar density dissipated the air movement and reduced the potential drift hazard.
Calibrating Light Imaging and Light Scattering Probes for Atomizer Spray Characterization
Authors: van Vliet MW , Picot JJC
Published: December 2008

A laser light imaging probe (PMS OAP-260X) and a light scattering probe (PMS FSSP-100) were used to measure droplet size and frequency from atomizers used in aerial spraying. The tests were done at full scale in an aspirated flow wind tunnel, on a temporal basis. We are interested in knowing information of cumulative volume fraction vs droplet size. Methods and results are presented for calibrating the light scattering instrument for droplet size, refractive index, and sample cross-section. Calibration of the light imaging probe is discussed also. The problems of temporal and spatial coincidence are addressed. Results show that a properly calibrated FSSP-100 instrument can be used as a basis for volume flow rate of droplets in the small end of the spectrum. The OAP-260X probe data can then be spliced onto the FSSP-100 spectrum using a mass balance criterion. This is necessary when droplet frequency exceeds the instrument's (OAP-260X) response capability. The calibration technique is illustrated using results from tests on commercial atomizers such as the AU4000 rotary atomizer.
Charged Drop Application of Antisapstain Formulations to Lumber
Authors: Smith RS
Published: December 2008

In this investigation, formulations of PP523 and TCMTB were sprayed on softwood lumber using a specially-constructed “Electrodyn” sprayer developed by Imperial Chemical Industries PLC. The lumber surfaces were evaluated subsequently for overgrowth by fungi after a four-month period of incubation. Formulation PP523 provided adequate protection of hem-fir lumber while TCMTB gave suitable protection to the SPF lumber. Drop size and spray distribution patterns on the wood, were affected by Electrodyn nozzle voltage, fluid flow rates, height of the nozzle above the lumber surface and speed of lumber passing the nozzle. The wrap-around effect, caused by the charged drops, gave reasonable coverage by the chemical on the sides and lower surfaces of the lumber.

The efficiency of chemical application could be at least doubled when compared with conventional hydraulic sprays. Volumes of solution used to obtain adequate control of mould and stain on lumber were several magnitudes less than with hydraulic sprays while surface concentrations of chemical required to achieve protection were possibly lower. This technology could significantly advance the current procedures used in sawmills throughout Canada, by providing a more efficient and much safer method for applying antisapstain chemicals on lumber.
Assessment of Foliar and Ground Deposits of Aminocarb After Aerial Spraying Over Conifer Forests Using Two Types of Application Parameters
Authors: Sundaram KMS , Sundaram A
Published: December 2008

Experimental observations made in eight aerial spray trials on the inter-relationships between physical properties of two spray mixtures, application parameters, meteorological conditions, drop size spectra, ground deposits and foliar concentrations of aminocarb are described in this paper. In 1981, the spray mixtures were applied using a small aircraft (Cessna 188) equipped with four rotary (Micronair® AU3000) atomizers. In 1982, the mixtures were sprayed using a large aircraft (TBM avenger) fitted with 24 hydraulic (1010 Flatfan Teejet®) nozzles. Spray drops were collected at ground level with sampling cards, and ground deposits were assessed using glass plates. Canopy deposits were determined directly on live foliage. Physical properties measured were: viscosity, surface tension and volatility. In the 1981 study, the drop size spectra of both spray mixtures were narrow and contained small drops with a volume median diameter (DV.5) less than 50 μm. In the 1982 study, the drop size spectra were wide and contained large drops with a DV.5 greater than 100 μm. The ground deposits were higher in 1982 than those in 1981. Foliar deposits, on the other hand, were similar in both years. Among the three physical properties studied, viscosity and volatility played significant roles on the drop size spectra and ground deposits obtained in 1981; but no similar relationships could be found in 1982.
Shrouded Sprayer: Advantages in Field Application Systems
Authors: Rogers RB
Published: December 2008

Airflow studies around a simple shroud showed a low pressure area behind the shroud that lifts droplets out of the crop canopy and lifts them into the air to become airborne drift. An airfoil redirected the frontal jet, eliminating the low pressure area and reducing drift to less than 0.5% off-target deposit. Mechanically controlled drift gives the industry the ability to apply chemicals with mist-size drops to increase coverage and reduce carrier volumes to 10 L/ha. Freedom from drift means that chemical can be applied in the wind, greatly increasing the application timing accuracy and, consequently, improving reliability. Also, less drift means less contamination of both non-target humans and plants, thereby increasing operator safety. Field tests demonstrated the extra control and reduction in carrier afforded by mist-size drops.
An Invert Emulsion Replaces Dew in Biocontrol of Sicklepod — a Preliminary Study
Authors: Quimby PC , Fulgham FE , Boyette CD , Connick WJ
Published: December 2008

Applications of the fungus, Alternaria cassiae Jurair and Khan with and without an overspray of a new experimental invert (water-in-oil) emulsion were evaluated for control of sicklepod (Cassia obtusifolia L.) weed in soybeans ‘Forrest’ with and without a post-treatment dew period under controlled environmental conditions. The unique experimental invert emulsion was developed and applied with specialized air-assist atomizing nozzles as an overspray to provide moisture and to retard evaporation of the water applied so that the fungal spores could germinate and infect the target weeds under relatively dry conditions. Spores applied in an aqueous carrier alone or in an aqueous carrier followed by an overspray of the invert emulsion caused 100 percent mortality by 16 days after treatment if the sicklepod seedlings were exposed after treatment to 18 h of dew. Spores applied in the aqueous carrier alone and in the aqueous carrier followed by an overspray of the invert emulsion caused 0 and 88 percent mortality, respectively, without the dew period. This is the first report known to us of a technique to obtain infection and weed control with a foliar-applied weed pathogen without dew or mist.
Aerial Application of a Granular Herbicide
Authors: Cochran RJ , Boring LE
Published: December 2008

The aerial application of liquid pesticides has been used for many years as an effective, economical means of applying chemicals to large acreages. Aerial application of solid formulations has had only limited usage and has been mainly applied from fixed wing aircraft.

A granular herbicide formulation has been developed for herbaceous and brush control in conifer forest management. Aerial application provides an economical method to spread herbicides evenly across timberlands which can be very rough and have existing trees. Because timberlands are usually far from air fields used by fixed wing aircraft, helicopters are used flying out of locally cleared helipads. Since there was no commercially available equipment existing, application equipment was modified and application procedures developed to accurately apply the granules from helicopters. Refinements in the formulation and equipment have allowed application rates of 1000 acres per day.
Effects of Heat Flux and Irradiation-Induced Changes in Water Chemistry on Zircaloy Nodular Oxidation
Authors: Franklin D , Li C-Y
Published: December 2008

Nodular corrosion data of Zircaloys in water reactor environments are reviewed to show that in addition to variables such as temperature, water chemistry, material, and irradiation flux, heat flux is an important variable. Qualitative evidence that suggests increased nodular oxidation rate with increasing heat flux at low heat fluxes and a reverse dependence at high heat fluxes where boiling occurs is presented. Previous quantitative measurement of incremental nodular corrosion above uniform corrosion is used to develop a phenomenological model that describes the dependence of nodular corrosion on these variables.
Effect of Chemistry on Elevated Temperature Nodular Corrosion
Authors: Weidinger HG , Garzarolli F , Eucken CM , Baroch EF
Published: December 2008

Short-term autoclave tests are currently being used by some as a selector for nodular corrosion, a phenomenon which is observed in boiling water reactors. The effects of composition have been evaluated previously with respect to mechanical properties. The present study extends this earlier work on chemical effects to include corrosion performance in 500°C steam, one of the predictor tests. Fifty-three ingots having compositions within as well as outside the specification range for the Zircaloys were melted and fabricated into plate and strip using a conventional fabrication procedure that incorporated an intermediate beta quench followed by working and annealing in the upper alpha region.

The roles of various elements, singly and in combination, on 500°C corrosion were examined systematically. The alloy elements covered the following ranges: tin, 0.02 to 5.14 wt%; iron, 0.04 to 0.57 wt%; chromium, 0.04 to 2.76 wt%; and nickel, 0.003 to 0.046 wt%. In addition, carbon, silicon, aluminum, and phosphorus were evaluated over the range of standard Zircaloys.

The frequency and severity of nodule formation were generally related to the weight gain for both static and refreshed autoclave tests. The transition elements chromium, iron, and nickel exhibited the most pronounced effects, with the effect of nickel being dominant. High weight gains are generally observed at low concentrations of iron, chromium, and nickel, and low weight gains are observed at high concentrations of these elements. The composition of Zircaloy is in the transition region between the two extremes. Equations were developed describing this relationship.

Heat treatments that affect the distribution of the intermetallics have a significant effect on the corrosion properties of Zircaloy. Process temperatures in the high alpha-range generally lead to high weight gains for Zircaloy. For beta quenching the results depend on the specific conditions of the quench and of the test performed. Testing in static steam resulted in low weight gains for all beta treatments studied, while testing in refreshed steam led to different results depending on quenching rate. In the refreshing autoclave tests high weight gains are observed at low quenching rates from the beta.

The best results are obtained by beta quenching at a minimum rate of above 5 K/s. For materials processed in this manner low weight gains persist even after long time annealing in the high alpha-range and sensitivity to nodular corrosion develops in Zircaloy only at temperatures close to the alpha/beta-transition.
Zircaloy Fuel Cladding Behavior in a Loss-of-Coolant Accident: A Review
Authors: Erbacher FJ , Leistikow S
Published: December 2008

This paper reviews the state-of-the-art experimental work performed in several countries with respect to the acceptance criteria established for the emergency core cooling (ECC) in a loss-of-coolant accident (LOCA) of light water reactors (LWRs). It covers in detail oxidation, embrittlement, plastic deformation, and coolability of deformed rod bundles.

The main test results are discussed on the basis of research work performed at the Karlsruhe Nuclear Research Center (KfK) within the framework of the Nuclear Safety Project (PNS). Reference is made to test data obtained in other countries.

The paper concludes that the major mechanisms and consequences of oxidation, deformation, and emergency core cooling are sufficiently investigated in order to provide a reliable data base for safety assessments and licensing of LWRs. All test data prove that the ECC criteria are conservative and that the coolability of a LWR and the public safety in a LOCA can be maintained.
Study by Thermoelectric Power Measurements of Recovery and Recrystallization of Cold-Rolled Zircaloy-4 Sheets
Authors: Merle P , Vauglin C , Fantozzi G , Derep JL , Charquet D
Published: December 2008

The microstructural evolution of cold-rolled Zircaloy-4 sheets during agaings at temperatures from the ambient up to 700°C is studied by thermoelectric power (TEP) measurements. The analysis of various factors having an influence on TEP of Zircaloy shows that this technique is well suited to the study of recovery and recrystallization. It is shown that, in the temperature range 450 to 700°C, carbon has a retarding influence on recovery as well as on recrystallization. The activation energy of recrystallization increases with carbon content, and the effect of this element seems to be identical to that of other interstitials such as oxygen. Measurements show that TEP of freshly cold-rolled Zircaloy-4 sheets vary during agings from the ambient up to 300°C. This evolution is composed of two stages corresponding to the formation of atmospheres of interstitial solutes around dislocations and to the formation of oxygen clusters on dislocation nodes.
Residual Stresses in Textured Zirconium Alloys
Authors: MacEwen SR , Tomé C
Published: December 2008

The elastic, plastic, and thermal properties of zirconium-base alloys are highly anisotropic. Consequently, thermomechanical treatments will leave fabricated components with high residual stresses. These stresses play an important role in determining subsequent mechanical properties and the dimensional stability of reactor-core components. When a component is deformed or subjected to a change in temperature, the total strain in any given grain will be accommodated elastically, plastically by shear on the active slip systems or by twinning, and by thermal expansion. The partitioning among the three modes depends not only on the particular orientation of the grain but also on the orientation of the other grains (texture) in the component. A self-consistent analysis, based on the concept of the hcp single-crystal yield surface, has been developed to predict the way that grains in a textured polycrystal respond to arbitrary external thermal or mechanical loading. The calculation follows the elastic-plastic evolution of strain inside each grain, taking into account the anisotropic elastic constants and thermal expansion coefficients. Workhardening due to shear on the active slip systems is included explicitly in the analysis.

Specific examples of the residual stresses produced by tension-compression deformation and thermal cycling of Zircaloy-2 rod will be described. It will be shown that the elastic-plastic transition in Zircaloy-2 requires much larger uniaxial strain and results in much higher apparent workhardening rates than in fcc metals. The predictions will be compared with experimental measurements of residual stresses made using the technique of neutron diffraction.
Cold-Rolled and Annealed Textures of Zircaloy-4 Thin Strips
Authors: Charquet D , Alheritiere E , Blanc G
Published: December 2008

Two types of texture have been observed on cold-rolled 0.5-mm-thick Zry-4 strips. The first type (T-texture), characterized by the (0002) poles oriented towards the transverse direction, is similar to that observed on Zry-4 tubes and on pure zirconium strips. In the second type (L-texture) the (0002) poles are oriented towards the longitudinal direction. Actually observed textures consist of a mixture of these two types. The influence of cold working and annealing on texture formation and evolution is also described. On fully recrystallized strips, two types of texture have been observed. The first is the T-texture; in the second type (C-texture) the (0002) pole lies parallel to the normal direction.
Zirconium-Barrier Cladding Attributes
Authors: Rosenbaum HS , Rand RA , Tucker RP , Cheng B , Adamson RB , Davies JH , Armijo JS , Wisner SB
Published: December 2008

This metallurgical study of Zr-barrier fuel cladding evaluates the importance of three salient attributes: (1) metallurgical bond between the zirconium liner and the Zircaloy substrate, (2) liner thickness (roughly 10% of the total cladding wall), and (3) softness (purity). The effect that each of these attributes has on the pellet-cladding interaction (PCI) resistance of the Zr-barrier fuel was studied by a combination of analytical model calculations and laboratory experiments using an expanding mandrel technique. Each of the attributes is shown to contribute to PCI resistance.

The effect of the zirconium liner on fuel behavior during off-normal events in which steam comes in contact with the zirconium surface was studied experimentally. Simulations of loss-of-coolant accident (LOCA) showed that the behavior of Zr-barrier cladding is virtually indistinguishable from that of conventional Zircaloy cladding. If steam contacts the zirconium liner surface through a cladding perforation and the fuel rod is operated under normal power conditions, the zirconium liner is oxidized more rapidly than is Zircaloy, but the oxidation rate returns to the rate of Zircaloy oxidation when the oxide phase reaches the zirconium-Zircaloy metallurgical bond.
Iodine-Induced Stress Corrosion of Zircaloy Fuel Cladding: Initiation and Growth
Authors: Brunisholz L , Lemaignan C
Published: December 2008

Because of its impact on nuclear power plant reliability, fuel cladding failure induced by pellet cladding interaction is a problem of major concern. It is usually analyzed as stress corrosion cracking caused by volatile fission products like iodine.

In order to analyze the mechanisms of iodine stress corrosion in Zircaloy-4 cladding tubes, a series of tests have been carried out on recrystallized and stress-relieved cladding from different origins. The tubes were pressurized in the presence of iodine (1.5 mg cm−2 Zry) at 350°C, and the time to failure was measured versus applied hoop stresses.

In order to be able to analyze independently initiation and growth, a special procedure has been developed to induce a small fatigue crack (⋍200 µm) in the inner wall of some specimens before the pressurization test. After failure of the specimen, the initial fatigue crack and the subsequent stress corrosion crack are clearly separated. Using linear elastic fracture mechanics analysis, those measurements allowed us to determine the stress corrosion average crack growth rates and the threshold stress intensity factor for crack growth KIscc.

The effect of loading path has been analyzed during slow tensile tests (5 µm s−1) performed under iodine vapor at 350°C along the axial and circumferential orientations. Differences in time to fracture and loss of ductility for the two orientations can be explained in terms of crack growth along preferred crystallographic planes or grain boundaries that were confirmed by SEM fracture surface observation.
Chemical Inhomogeneity Populations in Various Zircaloy Claddings and Their Association with SCC and Corrosion Resistance
Authors: Tasooji A , Miller AK , Cheung TY , Brooks M , Santucci J
Published: December 2008

A technique has been developed that permits detection and characterization of sparsely distributed chemical inhomogeneities in Zircaloy. These inhomogeneities have previously been observed at the origins of iodine stress-corrosion cracks but are not detectable by, for example, simple scanning electron microscopy (SEM) examination. The technique uses radioactive iodine to “label” the chemical inhomogeneities, autoradiography to detect their locations, and SEM and energy-dispersive X-ray analysis (EDAX) to further characterize them. Large areas of surface have been surveyed and statistically meaningful populations of chemical inhomogeneities measured for five different lots of Zircaloy cladding. Inner surfaces and cladding cross-sectional surfaces have been studied. There are clear differences in chemical inhomogeneity size distribution and composition between the various claddings.

For three of the claddings characterized in this work, the previously measured stress-corrosion cracking (SCC) threshold stresses correlate well (inversely) with the new data on their average chemical inhomogeneity sizes. Of special interest is the fact that the most SCC-resistant cladding contains far fewer iron-bearing inhomogeneities than the other claddings.

To investigate whether chemical inhomogeneities relate to the aqueous corrosion performance of the material, a blind test was conducted on 14 samples representative of material previously tested in an autoclave at 500°C at 10 342 kPa (1500 psi) for 24 h. The unautoclaved companion samples were examined by autoradiography. The results show that, in general, materials with good corrosion performance in the high-temperature autoclave tests are also characterized by a low population of chemical inhomogeneities and vice versa.

Selected chemical inhomogeneities were cross-sectioned and studied further using the electron microprobe. These measurements confirm the existence of a silicon- and aluminum-rich region extending about 10 µm below the surface, and also indicate iron-rich locations which coincide with silicon-rich locations and have spacings on the order of the grain size. The distribution of aluminum is relatively flat.

The implication of these observations in terms of possible origins of the chemical inhomogeneities is discussed briefly.
Laboratory and Mine Dust Explosion Research at the Bureau of Mines
Authors: Cashdollar KL , Sapko MJ , Weiss ES , Hertzberg M
Published: December 2008

This paper describes the results of recent dust explosibility testing in a 20-L laboratory chamber and in the Bruceton and Lake Lynn Experimental Mines in Pennsylvania. Laboratory data on the lean flammability limits for coals and oil shales are compared to mine data for both predispersed tests and nominal loadings that are dispersed by a gas ignition zone. A linear relationship for the lean flammability limits for mixtures of bituminous coal dust and methane gas was measured in both laboratory and mine tests. This paper also compares data on the amount of limestone rock dust necessary to inert coal dusts and coal-methane mixtures. The good agreement between the 20-L chamber data and the mine data means that the laboratory chamber can be used for screening tests before full-scale mine tests.
Research on the Suppression of Coal Dust Explosions by Water Barriers
Authors: Zhou D-B , Lu J-Z
Published: December 2008

Chongqing Coal Research Institute has been conducting experimental research on water barriers to determine their feasibility for installation in underground coal mines in China. The performance tests of 40- and 80-L tubs indicate that when the dynamic wind pressure is equal to or more than 0.16 kg/cm2 they rupture and water disperses to form a spray cloud, which lasts for 75 to 150 ms. The cloud is 7 m long and spreads about 4 m wide. For extinguishing coal dust explosions, water barrier tests were conducted in our experimental gallery (896-m total length and 7.2-m2 cross section). The test results have shown that barriers can effectively suppress coal dust explosions propagating at speeds of 80 to over 700 m/s. It was found that a delay time of from 2 to 1100 ms between barrier operation and flame arrival does not reduce their effectiveness. However, when the flame propagates slowly and the explosion pressure does not develop sufficiently, the barrier can be ineffective. Further research is necessary to improve the tub materials, their design, and their configuration.
Coal Pulverizer Explosions
Authors: Carini RC , Hules KR
Published: December 2008

In 1981 the Electric Power Research Institute (EPRI) began a research program to study pulverized coal fires and explosions in the U.S. utility industry. Historical trends resulting from an industry-wide survey and experimental results of explosion-related testing are discussed. The survey indicates that explosive events are occurring at a rate of approximately one explosion for each unit every three years resulting in an industry cost of one billion dollars annually. The historical trends show that although coal type has a large influence on explosion frequency, it is not the only significant factor in setting explosion hazard levels. Laboratory experiments were performed in full-scale test rigs that allowed triggering and monitoring of coal system explosions on demand. Ignition events that remained within the coal pipe created only weak pressure rise, while ignition events within the simulated pulverizer volume created explosions exceeding 70 bars (7000 kPa). These experiments showed that explosion characteristics depend on dust concentration, ration of pulverizer volume to coal pipe area, as well as coal type.