bluuebunny/crossref_metadata_2025 huggingface dataset:
Expedited Enforcement of UST Regulations in New Mexico
Authors: Sutton-Mendoza SA
Published: March 2009

New Mexico is the first state to implement an expedited enforcement program to enhance compliance with the Underground Storage Tank Regulations (USTR). UST field inspectors conduct inspections at UST facilities to ensure compliance with the USTR. If the inspector detects a violation, a field Notice of Violation is issued to the owner/operator and a penalty assessed. Prior to expedited enforcement 14% of the violations were corrected. Since implementing the program the Underground Storage Tank Bureau has conducted 592 inspections, issued 181 field Notices of Violation and 52% of those cited have complied. As a result of the enforcement program 85% of the facilities inspected are in compliance with USTR. This program has been successful in gaining compliance with USTR, specifically the release detection requirements.
Impact of Standards and Certification on Environmental Impairment Liability Insurance Programs
Authors: Gulledge WP
Published: March 2009

Environmental impairment liability (EIL) insurance is available for petroleum storage tank and other environmental exposures. Recent standards and performance criteria for leak detection for underground storage tanks (USTs) and other technical standards for USTs have been both a benefit and an interference to risk-based underwriting of storage tank EIL insurance programs. Insurance underwriters and state financial responsibility program administrators are confronted with confusing information to manage these environmental risks.

Standards and certification are also key issues for site assessment programs. Recent activities from ASTM and the Institute for Environmental Auditing (IEA) have addressed the need to increase the professional stature of site assessments and environmental management. Reaction and acceptance of these efforts by the users have been mixed. Ultimately, these efforts will greatly impact insurance coverage for environmental risks.
Screening Methodology for Selecting Clean-Up Technologies at Leaking Underground Storage Tank Sites
Authors: Fan C-Y , Tafuri AN
Published: March 2009

This paper presents a methodology for evaluating site conditions and for screening various remediation technologies that may be applicable to cleaning up releases of petroleum products from underground storage tanks (UST). The methodology enables the user to develop a conceptual understanding of site conditions before the completion of extensive field studies, define remediation goals, evaluate technologies capable of meeting remediation goals, and identify monitoring requirements during and after remediation.

Working with site-assessment data, the methodology provides an approach for a preliminary determination of petroleum product location in unsaturated and saturated zones and for evaluating the likelihood of pollutant migration within a site's soil matrix. Worksheets then guide the evaluation of how site conditions pertain to factors that favor or inhibit the success of specific technologies.
Influence of Two Adjuvants on Rain-Washing Characteristics of Glyphosate Deposits from Trembling Aspen Foliage, Following a Field Spray Application
Authors: Leung JW , Webster GRB
Published: March 2009

Three end-use mixtures, Vision-W, Vision-Ethomeen-W and Vision-Silwet-W, were prepared from Vision®, a formulation concentrate of glyphosate, without and with Ethomeen® T/25 and Silwet® L-77 adjuvants. The mixtures were sprayed at a dosage rate of 1 kg of glyphosate in 35 L per ha, over young trembling aspen trees selected in a one-year-old cut-over site in northern Ontario, Canada, using the Herbi® spinning disc atomizer. Samples of foliage were collected at 1.0 h after glyphosate treatment to determine the initial deposits of glyphosate. At 36 h after treatment, the trees were subjected to a simulated rainfall of 5 mm using a Solo® backpack sprayer. Foliar samples were collected prior to and after rainfall, to determine the rain-washing characteristics of the residual deposits.

The Herbi atomizer provided large droplets of the three end-use mixtures with a volume median diameter of about 300 to 350 μm. Foliar deposition was almost quantitative because 95% of the applied glyphosate was deposited initially on foliage. The average amount of glyphosate washed-off in the rainfall was 55% for Vision-W, 40% for Vision-Ethomeen-W and 36% for Vision-Silwet-W. The data thus indicated a reduction of 15% and 19% in the amount of glyphosate washed off from foliage, when Ethomeen and Silwet adjuvants were present in the end-use mixtures.
Use of Pregelatinized Starch and Other Polysaccharides for Improved Storage and Efficacy of Biocontrol Agents
Authors: Bothast RJ , Schisler DA , Jackson MA , VanCauwenberge JE , Slininger PJ
Published: March 2009

Nutritional and environmental factors present both during inoculum production and the infection or colonization process ultimately influence effectiveness of biocontrol agents. Conidial efficacy of Colletotrichum truncatum NRRL 13737 for control of Sesbania exaltata was evaluated after providing amendments to spores which had been produced in media with differing carbon to nitrogen (C:N) ratios. Conidia produced in a medium with a C:N ratio of 10:1 incited more severe disease in seedling assays than spores produced in 30:1 medium, though amending with pregelatinized starch increased the efficacy of 30:1 spores to levels comparable to 10:1 spores without amendment. Casamino acids increased the severity of disease incited by 10:1 spores but generally did not influence 30:1 spore efficacy. Cell viability after storage, seed germination, and disease suppression were evaluated after treating wheat seed with various formulations of Pseudomonas fluorescens 2-79 (NRRL B-15132) cells of different age for control of take-all (caused by Gaeumannomyces graminis var. tritici). Viability, germination, and disease suppression declined over 6 months storage. Effects of cell age (24, 48, and 96 h) were not consistent. Cells resuspended in methylcellulose-water (MW) survived better on wheat seed than cells resuspended in methylcellulose-broth (MB) and MW treated seed retained a higher germination rate. However, disease suppression was best on MB treated seed.
The Reduction of Herbicide Leaching Using Vinyl Pyrrolidone Copolymers and Methyl Vinyl Ether Maleic Acid Ester Copolymers
Authors: Narayanan KS , Singh M , Chaudhuri RK
Published: March 2009

Pesticides applied to soil can be leached by runoff and/or groundwater to contaminate surface water. Most pesticide residues in surface water degrade fairly rapidly and contamination is often transitory. Groundwater is a primary source of drinking water in many rural areas. Residues in cold groundwater are only slowly degraded and are of serious public concern. The objective of this study was to reduce herbicide leaching by controlling mass flow and diffusion with polymerherbicide interactions. The effect of several vinyl pyrrolidone polymers and copolymers and methyl vinyl ether/maleic acid copolymers and derivatives on three highly leachable herbicides, selected from three different chemical families, were investigated in soil columns (8 cm high, 7 cm diameter) using candler fine sand (typic Quartzipsamment). 14C-herbicide solution with or without polymer was applied to presaturated soil columns, leached with four volumes of water (12.8 cm rainfall) and the resulting radioactivity was determined in the leachate. Several polymers decreased leaching of herbicides by 10 to 60% compared to their respective herbicide controls. In bioassay studies, herbicide (5 kg/ha) with or without polymer (5 kg/ha) was applied to repacked presaturated soil columns (120-cm high, 10-cm diameter) and leached with water (2.5 to 7.5 cm of simulated rainfall). After leaching, the columns were split vertically in half and seeded with alfalfa or ryegrass to determine the distance of herbicide leached. Bioassay results showed up to 25% reduction in leaching of herbicides with some polymers in sandy soil. Structure-activity relationships of the polymers will be discussed.
The Relation of the Pourability of Suspension Concentrates to their Viscoelasticity
Authors: Dexter RW , Szamosi J
Published: March 2009

The pouring characteristics from 1 liter HDPE containers have been determined for a number of commercially available suspension concentrates and model solutions with controlled rheology. The pouring phenomenon was observed to occur in two phases: a rapid continuous stream over approximately the first 30 seconds, followed by a slower, dropwise drainage. The rheology of the fluids was measured using a Rheometrics RFS II variable strain rheometer in the dynamic mode. It was found that the weight of formulation remaining in the container after 1 minute's pour out correlated well with the viscous modulus of the fluid. The subsequent rate of drainage of the formulation from the container was dependent upon the elastic modulus of the formulation. Guidelines for development of formulations with efficient pour properties are given.

The rinsing properties of several model fluids were examined. The rinsing efficiency was markedly dependent upon the amount of residue remaining after the initial pour and drain. It appears that the more elastic fluids do not wash off the container walls as effectively as the less elastic ones.
Effect of Polyethylene Glycol on the Adsorption of Polymeric Surface Active Agent and the Stability of Concentrated Suspensions
Authors: Memula S , Jimenez A , Berger CH
Published: March 2009

The adsorption and the configuration of the polymeric surfactant at the solid / liquid interface are vital to the steric and electrostatic stability of suspension concentrates. The process of adsorption and the adsorption layer thickness to obtain the most stable system is a complex task and depends on many factors.

This paper discusses the stages involved in the optimization of a suspension concentrate and the results of a study of the effect of polyethylene glycol on adsorption of block polymer where the molecular weights of two components are varied. A model system was chosen to study various physico chemical properties such as adsorption, wetting, contact angle, dynamic surface tension, dilution performance, suspensibility, freeze-thaw stability, particle size, and rheology. Our results showed interesting correlations between these properties and the structure of the polymeric surfactant.
Effects of Solvents on Polymeric and Elastomeric Materials in Agricultural Chemical Systems
Authors: Sandler RL , Verbelen RA
Published: March 2009

The objective of this study was to provide a source of compatibility data between commercially available polymeric and elastomeric materials and solvents used in the Agricultural Chemical Industry The following solvents were selected: aromatics; alkylbenzene predominantly C10, alkylnaphthalene predominantly C10–12, naphthalene depleted alkylnaphthalene C11–12, aliphatic; aromatic free C11–12 hydrocarbon solvent, isoparaffin; primarily C14 and C23 paraffinic petroleum oil These solvents were tested with the following materials: high density polyethylene, fluorinated high density polyethylene, polyvinyl chloride, nitrile butyl rubber, ethylene propylene rubber, polychloroprene, perfluoroalkoxy resin, and vinylidene fluoride.

The results of the elastomeric tests showed that perfluoroalkoxy and vinylidene fluoride resins are excellent choices for all of the solvents tested, ethylene propylene rubber was shown to be the poorest choice of all With respect to the polymeric tests, the second and third degree fluorinated high density polyethylene materials were compatible with all of the solvents. Polyvinyl chloride, however, was not compatible with aromatic solvents

As a word of caution, the information in this paper can only be used as a starting point in the selection of polymeric and elastomeric materials with compatible Ag-Chem solvents The Agricultural Industry must combined this information with additional information such as choice of active ingredients, surfactants, and application systems before the final selection of packaging and seal materials can be made
The Effect of Diluent Oils on the Electrostatic Atomization of Some Insecticides
Authors: Downer RA , Hall FR , Escallon EC , Chapple AC
Published: March 2009

Concern for environmental contamination, operator safety and economics has led to a desire to apply pesticides in as low an application volume as possible without loss of efficiency of the application device or pesticidal activity. One way to accomplish this is by use of electrostatic applicators, some of which require oil instead of water as the pesticide diluent.

The objective of this study was to determine the effect of different concentrations of Ambush 2E, Capture 2E, and Asana XL, mixed with Terra Prime Oil II, on the droplet spectra produced by an electrostatic atomizer. Each mixture was atomized using a single ligament nozzle. Droplet spectra were determined using an Aerometrics PDPA-100D phase/Doppler particle analyzer.

Ambush had the greatest effect on oil atomization. Ambush at 10% concentration gave the best atomization characteristics across the most suitable voltage range. Increasing the concentration of Capture gave a decrease in Dv0.5. With Capture at 20%, stable atomization was only attainable between 15 and 30 kv. Asana XL showed less change in Dv0.5 than either Capture or Ambush.

The resistivity of all the test mixtures was measured and was shown to be a key parameter in determining the potential atomization characteristics of the spray cloud.
Droplet Size Spectra of Dipel™ Sprayed Through Different Atomizers
Authors: Sanderson R , Hewitt AJ , Huddleston EW , Devisetty BN , Melchoir GL , Ross JB
Published: March 2009

Droplet size spectra were measured for water and two aqueous flowable (AF) formulations of Bacillus thuringiensis (“Dipel™ ”) sprayed from nozzles under simulated aerial application conditions using a Malvern 2600c laser particle sizer in a wind tunnel operating at 27, 45 and 58 m/s. Undiluted formulations of Dipel 6AF and a modified Dipel 6AF were evaluated.

A Teejet 8004 flat fan nozzle and a Micronair AU5000 rotary cage atomizer were tested. The hydraulic nozzle was evaluated at orientations of 45, 90, and 135° to the airflow with a liquid pressure of 276 kPa (40 psi). The rotary atomizer was tested at liquid flow rates of 2000, 4000, and 8000 mL/min and rotation rates of 4400, 6200 and 9500 rpm.

Spray deposit patterns on Kromekote cards were assessed in field trials using a Cessna AgHusky aircraft fitted with either 8004 nozzles or AU5000 atomizers. The spray liquids were tagged with a tracer dye for subsequent image analysis to determine droplet densities.

The Volume Median Diameter (Dv0.5) droplet size values for the sprays measured in the wind tunnel ranged from 146 to 404 μm. for the hydraulic nozzle and 34 to 159 μm. with the rotary atomizer. The Dv0.5 values obtained with the hydraulic nozzle increased with lower wind speed and lower nozzle angle relative to the airstream. The Dv0.5 values obtained using the rotary atomizer increased with higher liquid flow rate, lower airstream velocity and lower atomizer rotation rate. The Dv0.5 was always lower for the modified Dipel than for the standard product sprayed under the same conditions. The Dv0.5 produced by water was lower than both Dipel products under given conditions.

Droplet deposition densities on Kromokote cards were higher for the modified Dipel 6AF than for the standard product when sprayed through either the AU5000 rotary cage atomizer or the 8004 hydraulic nozzles.
Development of Process Control Charts (X and R) for Evaluating Performance of 8004 Fan Nozzles
Authors: Krishnan P , Seemans D , Gottfried S , Kemble LJ
Published: March 2009

Fan nozzles are very popular for spray applications. Problems can arise, however, from the use of worn out nozzles. An example would be the over-application of the chemicals. The objective of this study was to develop X and R process control charts for evaluating the performance of 8004 brass fan nozzles. The nozzle was considered to be worn out when its flow rate exceeded 110% of the nominal flow rate at the selected nozzle pressure (1692 ml/min @ 347.5 kPa). Water was used in all the trials. Twelve 8004 fan nozzles were used in this study. The flow rate from each nozzle was measured as a function of time in hours. The nozzles began to wear at 398.05 hours. All the nozzles had worn out after 591.2 hours. X and R charts were developed for each nozzle. A typical plot is shown. Plots of the sample grand average (X), average sample range (Rt) and system range (Rs) values of the flow rate of 8004 fan nozzles at specific lifetime are shown. Rs values indicate that the control must be based on control charts for each individual nozzle on the boom. This is unfortunate from an economic point of view because it requires more measurements and is more expensive than controlling the whole system as one unit.
Comparative Performance of Culigel® Superabsorbent Polymer-Based Pesticide Formulations
Authors: Levy R , Nichols MA , Miller TW
Published: March 2009

Nonagglomerated (granules) or agglomerated (disquets) Culigel® Type IV or V superabsorbent polymer-pesticide compositions were evaluated against aquatic or terrestrial pests in a series of controlled-release bioassays. Bioactive agents included in the granular single-or joint-action pesticide formulations for use against mosquito larvae and/or aquatic weeds were bacteria or growth regulators and/or a herbicide. Bait-pesticide disquet formulations were evaluated against German cockroach nymphs or adults. Results of aquatic tests indicated that Culigel® Type IV granules can be used as single- or dual-product matrices for entrapment/encapsulation and prolonged controlled release of mosquito larvicides and/or herbicides. Comparative performance studies showed that single- or joint-action pesticide slow-release profiles from Culigel® Type IV granules were regulated or controlled in aquatic habitats by the type and concentration of a dispersant or two- or three-component dispersant complex. Long-term release of pesticides encapsulated within Culigel® Type V disquet formulations was demonstrated against immature and adult cockroaches.
A Screening Test for Water Dispersible Granules Produced by Spray Drying
Authors: Delli Coll HT
Published: March 2009

The ability of a droplet of a liquid to spread on and disperse a thin film cast from spray dryer feedstock is an indication of the ability of WDGs prepared from that feedstock to be wet by and disintegrate in the same fluid. The relative wettabilities and disintegrabilities of a series of formulations or variations of a single formulation can be compared prior to spray dryer trials. In this manner, the effect of wetting agents, dispersants, binders, and particle size distributions on wettability and disintegrability of WDGs can be quickly evaluated using criteria closely related to actual manufacturing conditions. This will mitigate the need to resort to costly and time consuming, large spray dryer trials during the initial development of a formulation or screening trials for formulation development. Additionally, initial screening would become less dependent on the use of small laboratory dryers which often bear little or no relationship to large commercial spray dryers. Many of the factors responsible for loss of disintegrability and dispersional stability during storage can also be evaluated so specific solutions for storage related problems can be identified.
Measurement of Dynamic Granule Dispersibility Using Particle Size Analysis
Authors: Haggard DN
Published: March 2009

This paper discusses a new method whereby the rate of granule breakdown, and thereby, one important aspect of Water Dispersible Granule (WDG) formulation quality can be determined objectively and quantitatively. The method uses particle size measuring apparatus to determine median particle size of a suspension of WDG's in water. Measurements are repeated at short time intervals until the median size has decreased to the size of the powder forming the granule or until the size has leveled off at some larger value.

Results can be expressed graphically, by mathematical equation, or for less critical measurement, in terms of time needed to reach original particle size. The measuring equipment must meet the following criteria: 1. It must measure a wide particle size range, from about 1 micron to about 1,000 microns. 2. It must make measurements of suspensions of relatively high concentration, approximating field concentrations. 3. It must be able to repeat measurement at intervals of a few seconds.

This paper demonstrates the method, discusses equipment used and shows results of measurements of a number of WDG's.
Grafted Polymers and Copolymers of Vinyl Pyrrolidone for Improved Water Dispersible Granules
Authors: Fu E , Chaudhuri RK , Narayanan KS
Published: March 2009

Polyvinylpyrrolidone (PVP), especially PVP K-30 (Agrimer™2 30), has been widely used in many different delivery systems. It can act as a solubilizing agent by complexing with many active ingredients, dispersing and suspending agent, viscosity enhancer, granule and tablet binder, and coating agent. In this paper, we describe its use and performance, along with vinylpyrrolidone-vinylacetate copolymer (Agrimer™ VA 6) and PVP grafted with butene (Agrimer™ AL 10), as a binder for water dispersible granules. The PVP-type polymers, at the 3% level, were used in a prototype atrazine 90DF formulation. The resulting granules, prepared by pan granulation, were found to have improved performance compared to granules made with conventional lignosulfonate binder. Less moisture was required to produce good granules, and granule conversion was increased. Slight to moderate improvements in dispersion properties were also obtained with Agrimer™ polymers, and a marked reduction in foam generation was obtained with Agrimer™ AL 10. The results also indicate possible synergistic effects for a mixture of Agrimer™ AL 10 and Agrimer™ VA 6 when used in combination.
A Review of Automotive Engine Coolant Technology
Authors: Hannigan HJ
Published: March 2009

A brief history of ethylene glycol application as an engine coolant is presented. Concurrent engine cooling system corrosion problems and coolant corrosion inhibition requirements are reported. Comments on current engine system corrosion problems are provided. Resistance to corrosion failure is shown to depend upon the correct combination of cooling system design, materials, coolant inhibition, and coolant retention.
Fleet Test Evaluation of Engine Coolants Using Sebacic Acid Inhibitor Technology
Authors: Adamowicz NC , Falla DF
Published: March 2009

A three-year, twelve-car municipal fleet test was conducted to compare the relative merits of an extended life sebacic acid coolant and current high silicate alkaline phosphate coolant used in North America. The test was conducted under rigidly controlled conditions in accordance with ASTM Practice for Testing Engine Coolants in Car and Light Truck Service (D 2847).

This paper will show the (1) depletion rates for chemical inhibitors used in the coolants and (2) actual photographs of cooling system component parts removed from the vehicles at the termination of this test.
An Overview of Cavitation Corrosion of Diesel Cylinder Liners
Authors: Hercamp RD
Published: March 2009

Cavitation corrosion (liner pitting) became a major problem for wet sleeve diese engines in the 1940s. For most engines, generous use of supplemental coolant additives (SCAs) adequately controlled pitting. In the mid 1980s, problems of SCA overtreatment such as silicate gelation, water pump seal seepage, and solder bloom raised awareness that too generous usage of SCAs was undesirable. This new awareness caused a general shift toward lower average SCA concentration.

In addition, engine power densities increased and load factors increased as speed limits increased. These factors increased the work load of the engine, resulting in a greater potential for liner pitting.

All these factors have resulted in an increased incidence of liner pitting in recent years. This paper is an overview to help place all the various factors related to liner pitting in perspective. The effects of engine design and materials, cooling system hardware, maintenance practices, and coolant composition are discussed.
Toxicity and Disposal of Engine Coolants
Authors: Hudgens RD , Bustamante RB
Published: March 2009

In recent years there has been considerable concern and controversy regarding both the toxicity and disposal of engine coolants. The toxicity of engine coolant relative to human or animal ingestion is largely a function of whether ethylene or propylene glycol is used to provide freeze point depression. The additives used in engine coolants to prevent cooling system deterioration have a measurable, but limited effect on toxicity. The general environmental effects are largely governed by the type of glycol as well as the contaminants that may be present in the coolant.

This paper presents a literature survey on the environmental, disposal, and toxicity issues surrounding engine coolants. In addition, an Acute Lethal Dose (LD50) study is presented comparing the LD50 of fully formulated PG antifreeze and supplemental coolant additives. A review of government laws and regulations covering disposal and management of waste coolant is also provided.
Application of Inductively Coupled Plasma (ICP) Emission Spectroscopy and Laser Ablation-ICP for Problem Solving in Coolant Systems
Authors: Zamechek W , McKenzie DA
Published: March 2009

Since the introduction of commercial instrumentation in 1975, inductively coupled plasma (ICP) emission spectroscopy has become the technique of choice for the determination of metals for many environmental, clinical, geological, and industrial applications. This is due to the method's relative freedom from interferences, speed, and flexibility. Described are some main characteristics of ICP spectroscopy, typical sample preparation approaches, and results for the analysis of coolants and deposits from different parts of cooling systems. Laser ablation-ICP (LA-ICP) was used to map the spacial distribution of metals across the surface of water pump seals. Design of the ablation system and standardization method are described. These results are compared to the analysis of the same samples by scanning electron microscopy/energy dispersive X-ray (SEM/EDX), electron spectroscopy for chemical analysis (ESCA), and scanning auger microprobe/energy dispersive x-ray (SAM/EDX).
The Chemistry of Oxalic Acid Cleaning of Engine Cooling Systems
Authors: Woyciesjes PM
Published: March 2009

Engine coolant candidates undergo a progression of tests to evaluate various physical properties and performance characteristics. Key to this test progression is the evaluation of the coolant in vehicles. It serves as the final check point, tieing together the results of the other various tests. In the fleet test, the corrosion protection and performance characteristics of an engine coolant are evaluated under actual use conditions.

The methodology used in testing a coolant in a passenger car or a light duty truck is critical. ASTM Practice for Testing In Car and Light Truck Service (D 2847) serves as an industry accepted standard for evaluating coolants in vehicles. This standard provides a full discussion of testing protocol.

Sections 9.3 and 9.4 of ASTM D 2847 outline the cooling system cleaning and conditioning procedures. These sections stipulate the use of oxalic acid as a chemical cleaner followed by a borate buffer conditioning fluid. The purpose of these two steps are (1) oxalic acid cleaning removes inhibitors, rust and other deposition from the cooling system, and (2) borate conditioning fluid removes excess oxalate to leave a conditioned surface in the cooling system which is neither detrimental nor beneficial to the performance of the coolant to be evaluated.

The ASTM Committee D-15 on Engine Coolants is reconsidering the use of oxalic acid cleaner in the automotive cooling system. Concerns have been raised regarding potential carryover effects oxalic acid could have on the performance of a coolant.

This paper reviews the chemistry of the oxalic acid cleaner as well as discusses the effects that oxalic acid cleaning has on the cooling system surfaces and its potential carryover effects to the test coolant. An understanding of the chemistry of oxalic acid is crucial in judging its efficacy as a cleaner to bring cooling system surfaces of a test vehicle to a reproducible base condition before performance testing.
Investigation of Deposits on Water Pump Seal Faces
Authors: Stafford RJ
Published: March 2009

Mechanical water pump face seals from heavy duty diesel on-highway engines which were reported to leak were analyzed and were compared to nonleaking seals. The siliconized graphite seal face pairs did not exhibit any significant wear of the faces. Coolant leakage was traced to deposit film build-up, which resulted in separation of the seal faces.

Analysis of the films by wavelength dispersive spectroscopy revealed elements from the coolant and coolant additives (Si, C, O, S, P, K, Na, B, Mo), corrosion metals from the engine (Fe, Cu, Cr) and hard water elements and contaminants (Ca, Mg, Zn, Al, Mn, Cl). Calcium from hard water and iron from corrosion are believed to accelerate the deposit formation.
The Relationship between Sealing Performance of Mechanical Seals and Composition of Coolants for Automotive Engines
Authors: Kiryu K , Hirata O , Yoshino A , Okada K , Hirabayashi H
Published: March 2009

Because the mechanical face seals in automotive water pumps play an important role in maintaining the good performance of engines, they must exhibit reliable sealing performance and long operating life. Generally, the sealing performance of mechanical seals is closely related to the properties of the liquid to be sealed. Automotive engine coolants are generally formulated with a variety of inhibitors to prevent corrosion and erosion of cooling system parts. A few of these inhibitors have a detrimental effect on the performance of water pump seals.

In this paper, representative types of deposit formation on sealing surfaces are reported. These seals were taken from pumps that failed due to seal leakage believed to be caused by a combination of coolant formulations, contaminations into coolant, and changes in engine operation conditions. The failure mechanisms and possible countermeasures involving the sealing materials, surface quality, and seal structure are discussed.
Coolant Maintenance and Extension of Coolant Life for Light Duty Vehicles
Authors: Hercamp RD , Remiasz RA
Published: March 2009

For many years coolant has been maintained and coolant life extended for heavy duty vehicles by using periodic additions of supplemental coolant additives (SCAs) and, in many cases, use of on-board by-pass nitration of the coolant. This concept has now been applied to light duty vehicles using a system consisting of coolant testing, off board full flow coolant nitration, and SCA addition to the coolant. In this manner, coolant life in light duty vehicles may be safely extended.

The system used to maintain and extend the life of the coolant is described. Glassware, bench, and simulated service testing data are reported, which support this approach.
A Multi-stage Process for Used Antifreeze/Coolant Purification
Authors: Richardson RC
Published: March 2009

Today, the subject of recycling used antifreeze/coolant is a popular and very complex issue. Legislation has forced users in some areas of the United States to either recycle or to pay for proper disposal through a licensed facility. Recycling represents a viable alternative to disposal but poses technical challenges never before attempted. This paper describes a unique, multi-stage purification process (MSPP) based on dual-bed deionization. The process can be effectively utilized in automotive or heavy-duty applications to remove inhibitors and contaminants in both ionic and particulate form. This paper presents (1) analysis of several used coolants before and after the process, (2) comparison of other recycling processes, (3) hazardous waste characterization testing of process components and finished product, and (4) complete corrosion/performance testing of the finished coolant.
An Evaluation of Engine Coolant Recycling Processes: Part I
Authors: Bradley WH
Published: March 2009

The Service Technology Group (STG) is an organization within General Motors (GM) responsible for providing service equipment and information to GM dealerships. STG is charged not just with the responsibility for current GM vehicles, but for the cars and trucks of the future as well. The tools, the procedures and the programs that technicians will use tomorrow must be created and validated today. Various staffs within STG address advanced serviceability readiness, special tool development, service research, and similar themes.

As the awareness of environmental issues has heightened, the disposition of spent engine coolant has begun to affect automotive service. One possible approach to this coolant disposition problem is that of coolant recycling. General Motors Service Technology Group has conducted a study in which the objective was to determine the efficacy of (state of the art) engine coolant recycling. Spent engine coolant was collected from vehicles and combined to form a reference coolant with a mean age of approximately seven years. Various coolant recycling processes were evaluated as they were required to process the reference coolant. Once the recycled samples were obtained, they were sent to an independent test facility. The test criteria was GM 1825M, a virgin coolant corporate specification.

Included in this study was the evaluation of off-site coolant recycling facilities that reformulate engine coolant for reuse.

In advancing its pro-active environmental policy, STG has initiated this study to evaluate the efficacy of engine coolant recycling. It is our belief that the results of this undertaking will be beneficial to our dealers, the environment, and our customers.
Variations in Composition and Crystallinity of ‘Hydroxyapatite (HA)’ Preparations
Authors: LeGeros RZ , Zheng R , Kijkowska R , Fan D , LeGeros JP
Published: March 2009

X-ray diffraction analyses of commercial and non-commercial ‘hydroxyapatite (HA)’ preparations as well as some biological apatites (enamel, dentin, bone) demonstrated a variability in crystallinity and composition before and after sintering. Coatings obtained by plasma-spraying calcium hydroxyapatite (HA) ceramic showed composition/crystallinity differences between the inner and outer layers of the coating; the coating composition consisting usually of: HA, amorphous calcium phosphate (ACP), α-TCP, β-TCP, tetracalcium phosphate (TTCP) and sometimes calcium oxide (CaO). The comparative extent of dissolution (EOD) in acid buffer of the non-sintered Ca-P materials was: ACP > DCPD > OCP > DCP > ‘AP’. For sintered materials, comparative EOD was: ACP*> TTCP > α-TCP > ß-TCP > HA. (‘AP’, calcium-deficient apatite; ACP, precipitated; ACP*, plasma-sprayed).

Results from this study underscored the need for the appropriate characterization of calcium phosphate materials using a combination of analytical techniques: x-ray diffraction, infrared and chemical. Since the dissolution of calcium phosphate materials depend on their composition and crystallinity, these results suggest that these materials used as bone grafts or implant coatings could affect their reactivity and stability in vivo.
Characterization of Composite Hydroxylapatite (HA) Coatings for Medical and Dental Devices
Authors: Sahay V , Lare PJ , Hahn H
Published: March 2009

Porous metallic/bioceramic composite coatings, produced by plasma arc deposition incorporating highly crystalline hydroxylapatite (HA) in a porous structure of titanium or cobalt-chromium-molybdenum, have been developed for medical and dental device applications. An otherwise brittle and weak HA coating has been anchored by a porous metallic underlayer which is strongly bonded to the substrate. Implants with such coatings have the advantage of mechanical fixation by bony ingrowth into the porous metallic structure coupled with enhanced biocompatibility achieved through the use of HA. This combination produces a more stable bone/implant interfacial region as compared to that achieved by a HA coating applied directly on the implant surface. Once bony ingrowth has taken place, strong bonding has been achieved even if bone resorption of the HA were to take place. Various thicknesses, densities and pore sizes of such composite coatings have been applied to dental and orthopedic devices and have been implanted in the U.S.A., Japan, and Europe showing excellent post insertion clinical results. Physical, mechanical, and chemical properties of selected coatings have been characterized and are reported herein.
Calcium Phosphate Precipitation on Calcium-Ion-Implanted Titanium in Electrolyte
Authors: Hanawa T , Murakami K , Kihara S
Published: March 2009

Calcium ions were implanted into a titanium surface in quantities of 1016, 1017, and 1018 ions/cm2. The ion-implanted surface was characterized using surface analysis techniques to determine the structure of the surface-modified layer formed by the implantation. The specimens were immersed in a neutral electrolyte solution whose composition resembled that of extracellular fluid. After immersion, the surface of the specimen was again characterized. The data revealed that the surface oxide of titanium grew after the calcium-ion-implantation. The surface-modified layer of the calcium-ion-implanted titanium was composed of titanium dioxide, which contained a calcium oxide and a complex oxide of calcium and titanium near the surface. The precipitation of calcium phosphate on titanium in electrolyte is tremendously accelerated by calcium-ion implantation, which is a surprising property for a biomaterial.
Influence of Electrolyte Resistance on Electrochemical Measurements and Procedures to Minimize or Compensate for Resistance Errors
Authors: Hack HP , Moran PJ , Scully JR
Published: March 2009

Electrolyte resistance is receiving increasing attention as a source of error in electrochemical measurements when not properly managed. This paper is designed as an introduction to, and summary of, this topic. A discussion of electrolyte resistance and its effect on the results of electrochemical measurements is presented. A broad spectrum of methods for minimizing or correcting the errors caused by electrolyte resistance is described. Several advanced ideas are also introduced. References are given to lead the reader to additional information.
IR Drop in Electrochemical Corrosion Studies— Part I: Basic Concepts and Estimates of Possible Measurement Errors
Authors: Ehrhardt WC
Published: March 2009

Electrochemical techniques used in the study of corrosion are particularly susceptible to errors due to IR drop when used to study systems such as the corrosion of steel in natural waters. The influence of the electrochemical measurement cell geometry on both the nature and the magnitude of the expected errors is reviewed. Also, the effect of a non uniform current distribution on the working electrode is examined. Expected errors for a range of corrosion rates and water conductivities that are typical of steel in cooling systems are presented for three types of experiments. These experiments are: simple linear polarization (polarization resistance), small range polarization, which is computer-fit to extract the corrosion rate and Tafel parameters, and full polarization.
Determination and Elimination of the Uncompensated Resistance in Low Conductivity Media
Authors: Mansfeld F , Chen YC , Shih H
Published: March 2009

The positive feedback and the interrupter technique have been used for the continuous elimination of the uncompensated resistance Ru during the recording of potentiodynamic polarization curves. The positive feedback technique was evaluated with a PAR model 173 potentiostat and a Solartron model 1286 potentiostat. The Solartron potentiostat was also used with the interrupter technique. The application of both techniques was initially evaluated with suitable dummy cells followed by the tests with steel and stainless steel in ethanolic hydrochloric acid (HCl) and in hydrazine. It was found that great care has to be used to determine the optimum parameters for the interrupter technique such as potentiostat bandwidth and interrupter frequency. The potential-time trace in the interrupter period needs to be observed on an oscilloscope in order to determine the optimum conditions. The saturated calomel electrode and similar reference electrodes cannot be used with the interrupter technique. Wire electrodes such as the silver/silver chloride (Ag/AgCl) or platinum give satisfactory results. The positive feedback technique is easier to use, however 100% compensation cannot be achieved in the PAR potentiostat. Since in most cases Ru will decrease during the recording of a polarization curve, it is difficult to obtain satisfactory results with this technique.
Correction of Experimental Data for the Ohmic Potential Drop Corresponding to a Secondary Current Distribution on a Disk Electrode
Authors: Esteban JM , Lowry M , Orazem ME
Published: March 2009

A numerical method is presented for adjusting experimental current-potential curves for the ohmic resistance corresponding to a secondary current distribution on a (rotating) disk electrode. The nonuniform current and potential distributions on the disk electrode cause the electrolyte resistance itself to be a function of measured current. The method described here is employed after the experiments are conducted and yields the Tafel slope as well as adjusted values for current density and surface overpotential that apply to the center of the disk. This facilitates the comparison of the experimental data to those obtained using mathematical models of the rotating disk electrode that, in the secondary current regime, apply strictly only to the center of the electrode. The Tafel slopes obtained agree to within 3 mV/decade with standard techniques for ohmic correction such as current interruption because, at the high current densities where the ohmic correction is most significant, the resistance correction approaches the primary resistance obtained by current interruption. The Tafel slope values for the two methods differ most for solutions of low conductivity. The major advantages of the ohmic correction method described here are that the experimental condition is never perturbed and that the method indicates the extent to which the current distribution is nonuniform.
Application of Numerical Simulations to Evaluate Components of Potential Difference in Solution
Authors: Farozic V , Prentice G
Published: March 2009

Computer simulation of the potential distribution in an electrochemical cell is a useful technique for estimating the ohmic drop and the potential gradient at any point in solution. Results of such simulations can be used in several applications. Since optimal location of a reference electrode depends, in part, on avoiding large potential gradients, calculations can be useful in determining where substantial gradients occur. One can alter the current and potential distribution by changing the cell geometry; the effects of changes can be quantitatively determined from a simulation. Knowledge of ohmic drop in the electrolyte is also of interest in applications such as cathodic protection, where large potential losses can lead to insufficient protection.

In this paper we illustrate the use of computer simulation for the computation of potential and current distributions from which we evaluate ohmic drop and surface overpotential. We used the finite-difference technique for several problems in which both field effects and electrode kinetics were important. Approximations introduced to reduce the complexity were assessed by comparing numerical results with analytical solutions.

Electrochemical systems of practical interest, the disk electrode and plane electrodes with gas bubbles in the electrolyte, were studied. In one variation, we showed the effect of recessing a disk electrode in the insulating plane. In a second set of calculations, we simulated a gas bubble layer near an electrode and determined the effects of increasing void fraction in the bulk electrolyte.
Ohmic Compensation in Desert Soil Using a Galvanostatic DC Bridge
Authors: Abraham D , Jones DA , Whitbeck MR , Case CM
Published: March 2009

A modified wheatstone bridge circuit has been used with success to compensate ohmic interferences in soil and other high resistivity corrosive solutions during galvanostatic (current controlled) dc measurements. Previous applications of the circuit have been reviewed and details of operation described. The most current use in our laboratories has been a study of corrosion in desert soils at the Nevada Nuclear Test Site (NNTS). A profile of desert soils samples with depth was obtained for electrochemical testing of lead and steel, which are construction materials for low level nuclear waste containers at NNTS. The soils were of naturally high resistivity, requiring compensation of ohmic interferences during electrochemical polarization measurements for corrosion rate (polarization resistance) determinations and cathodic protection requirements. Results are described briefly on effects of sulfate, chloride and carbonate, all of which can be derived from variations of soil composition with depth. Effects of added moisture content on all soil samples are also discussed.
Measurements of IR-Drop Free Pipe-to-Soil Potentials on Buried Pipelines
Authors: Thompson NG , Beavers JA
Published: March 2009

The purpose of this paper is to examine current interruption methods of estimating the level of polarization (off-potential) on a buried pipeline and to indicate some of the specific problems associated with field measurements. Data are reviewed that indicate the magnitude of the voltage (IR-drop) errors associated with potential measurements on buried pipelines. Oscilloscope tracings of pipe-to-soil potential waveforms are presented and a “spiking” condition is discussed which can significantly affect the ability to make an off-potential measurement at the instant of interruption. Stray currents and long-line currents, which can affect the ability to measure the level of polarization on an operating pipeline, are discussed. Methods of detecting stray currents and long-line currents are briefly presented.
Measurement of the Components of the Ohmic Resistance in Lithium/lodine (P2VP) Batteries
Authors: Streinz CC , Kelly RG , Moran PJ , Jolson J , Waggoner JR , Wicelinski S
Published: March 2009

It is well known that at high discharge rates (approximately 200 μA/cm2) the (Li/I2) (P2VP) battery suffers severely increased polarization. Recently, through the use of electrochemical impedance spectroscopy, it has been demonstrated that for cells with pelletized cathodes this increased polarization is dominated by ohmic effects. It has also been shown that monitoring the ohmic impedance throughout discharge provides an excellent means for understanding battery behavior. This is further illustrated in this paper. In this study cells containing only cathode material are utilized to determine the contribution of the cathode to the total cell ohmic impedance. It is demonstrated that prior to discharge the cathode impedance contributes greater than 60% of the full cell ohmic impedance. During discharge both the magnitude and the changes in the measured ohmic impedance are shown to be dominated by the LiI electrolyte layer. Further, it is concluded that the impedance of the cathode increases with increasing molecular weight of the P2VP polymer used in the cathode. As a result, the relative contributions of the cathode and electrolyte to the total ohmic impedance are a function of P2VP molecular weight.