bluuebunny/crossref_metadata_2025 huggingface dataset:
Calcium Phosphate Type Reference Material: Development, Preparation and Characterization
Authors: Tung MS , Sung P
Published: March 2009

A proposed calcium hydroxyapatite (HA) reference material has been prepared in large quantity in accordance with the following reaction in solution at 100°C : 5CaO+3H3PO4--Ca5(PO4)3OH+H2O

Stoichiometric HA powder with an atomic Ca/P ratio of 1.67 was obtained as determined by chemical analysis. The X-ray powder diffraction technique was used to evaluate the crystallinity with the measured width at half height of the diffraction peaks. The infrared spectra of the HA powder were obtained to determine the structure and to detect any minor phases. The thermal analysis indicated thermal stability and no decomposition. The thermodynamic solubility product (Ksp) of this HA, expressed as - logKsp (pKsp), was determined to be 57.7 at 25°C. Three additional HA samples prepared by different methods were also characterized and compared.
Changes in Characteristics Arising from Processing and the Effect on In Vitro Stability of Calcium Phosphate Ceramics
Authors: Radin S , Ducheyne P
Published: March 2009

Numerous studies have shown a three-fold possible effect of calcium phosphate ceramic (CPC) coatings on metallic implants: enhancement of bone tissue growth rates, bonding to bone, and reduction of metal corrosion product release. The two first effects are related to surface reactions of coatings upon implantation. In this study we focus on plasma spray (PS) induced changes in CPC phase compositions and surface areas, and their effect on the in vitro coating stability at physiological pH.

Hydroxyapatite (HA) and β- tricalcium phosphate (β-TCP) PS coatings were obtained from various commercial sources. All of these coatings underwent phase transformations and reduction of specific surface areas due to plasma spray processing. The dissolution rates of all of the PS coatings were found to significantly exceed those of the original HA or β-TCP, in spite of the reduction in specific surface areas. The increase in dissolution rates may be related to plasma spray induced transformations of starting monophases into multiphase coatings containing such components as oxyhydroxyapatite (OHA), α-TCP and tetracalcium phosphate (TTCP).

The multiphase stability depends upon components in the phase mixtures. The in vitro dissolution of monophases and their biphase combinations was studied to assess the influence of each phase component and their combinations. The dissolution rates of the monophase CPCs were found to increase in the order: HA <OHA <β-TCP <α-TCP <TTCP. Dissolution of biphase CPCs, α-TCP/ß-TCP or TTCP/α-TCP, increased with concentration of the more soluble component. Likewise, the dissolution of the PS coatings increased with concentration of the more soluble components. Therefore, PS coatings which contain such metastable components as OHA, α-TCP and TTCP can be expected to be more resorbable than starting HA or ß-TCP.
The Effect of Calcium Phosphate Ceramic Composition and Structure on In Vitro Precipitation Reactions
Authors: Ducheyne P , Radin S
Published: March 2009

The formation of a biologically equivalent carbonated apatite on the surface of synthetic calcium phosphate ceramics (CPC) may be an important step leading to bonding with bone. Reactions of several single phase CPCs upon immersion into a simulated physiological solution (SPS) with an electrolyte composition of human plasma were determined.The CPCs covered a wide range of stabilities from hydroxyapatites (HA) to metastable tricalcium phosphates (TCP) and tetracalcium phosphate (TTCP). Changes in chemical compositions of SPS and infrared spectral features after CPC immersion were analyzed. New phase formation was observed on all the CPCs. However, kinetics, compositions, and structures of the new phases were significantly different.

The studied CPCs can be characterized by the time to new phase formation in vitro: it was found to increase in the order: not well crystallized (wc) HAS <well crystallized (wc) HAs <α-TCP, TTCP <β-TCP. Only calcium-deficient HA (CDHA) and nwc stoichiometric HAs (s-HA) led to immediate new phase formation. The phase was identified as carbonated apatite. The wc HAs and β-TCP did not elicit carbonated apatite formation within the time frame of the experiment. TTCP transformed intensively to poorly crystallized carbonated apatite after 2 days of immersion.
Dense Hydroxylapatite (HA) and Microporous HA Resorption
Authors: Tofe AJ , Watson BA , Cheung HS
Published: March 2009

The mechanism of dissolution/resorption of today's bone grafting materials has received minimal attention. While an understanding of this mechanism is of importance to the clinical outcome in osseous regeneration of grafted sites, knowledge of the resorptive process also has direct extrapolation to HA coatings on implants.

In this presentation, the density and porosity of commercially available hydroxylapatite (HA) bone grafting materials were analyzed by scanning electron microscopy (SEM). The calcium phosphate phases and molecular constituents responsible for dissolution/resorption of hydroxylapatite (HA) were analyzed by X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. The lack of microporosity explains the nonresorptive nature of truly dense HA while the presence of microporosity leads to cell-mediated resorption. The latter was evaluated using an in vitro cell culture model with human fibroblasts. Scanning electron and light microscopy confirmed the endocytosis mechanism for porous HA and illustrated the inhibition of cellular invasion/resorption by dense HA.

A multi-analytical/spectroscopic approach coupled to in vitro cell culture studies provides insight into the dissolution/resorption of HA grafting materials and HA coating on implants.
Development of ASTM Standards for Bioceramics
Authors: Lemons JE
Published: March 2009

The potential for bioactive ceramic surgical implants has resulted in a number of studies conducted to provide physical, mechanical, chemical, electrical, and biological property characteristics. Previous investigations are now providing the basis for ASTM F-4 standards associated with the basic material properties as they relate to implant device applications. Extensions of data on particulates and device-oriented research have resulted in coatings on higher strength substrates. The theoretical advantages of calcium phosphate ceramic coatings are multiple and include: elements normal to the biological host; moduli of elasticity similar to bone; structural bonding to bone capable of transferring tensile forces; minimal conductors of heat, electrons, and substrate elements (a physical, chemical, and electrical barrier); a color similar to bone; and an established profile for host biocompatibility. Possible limitations of coatings for musculoskeletal load-bearing application can be directly related to mechanical and biological interaction; e.g., (1) inherent fracture and fatigue strengths of the ceramic-metal interface; and (2) a susceptibility to time-dependent biodegradation by the host that is mediated by cellular- and enzymatic-based interactions during normal bone modeling and remodeling. The current emphasis on standards development should provide a basis for comparing existing and new bioactive particulates and coatings with one another, and, subsequently, correlations with clinical investigations.
Theoretical Problems Related to Ohmic Resistance Compensation
Authors: Nisancioglu K
Published: March 2009

Current interruption, potential pulse methods, and the AC impedance technique are well accepted means of measuring the ohmic potential drop to an electrode for ohmic resistance compensation. An interpretation of the measured quantities is given, and the relationship between the measured and true parameters is established. Theoretical calculations indicate that a significant discrepancy may exist between the measured and the true corrosion rate, although the data are corrected for the ohmic resistance in the solution by conventional means. The cause of the error is a nonuniform ohmic potential drop to the electrode surface, and its magnitude is determined by geometry, position of the reference electrode, solution conductivity, and corrosion rate. Such errors in practice are specific to low-conductivity media and occluded cells with gaps or crevices. The magnitude of expected error is calculated for a few typical geometries. Possible ways of correcting the error are discussed. These include probe design, measurement technique, and methods of data analysis.
IR Drop in Electrochemical Corrosion Studies—Part 2: A Multiple Method IR Compensation System
Authors: Ehrhardt WC
Published: March 2009

The experimental methods available for IR drop correction in electrochemical corrosion experiments are briefly reviewed. A computer-controlled system that incorporates several different methods of IR compensation is described and some examples of its performance are presented.
Comparison of Current Interruption and Electrochemical Impedance Techniques in the Determination of Corrosion Rates of Steel in Concrete
Authors: Berke NS , Shen DF , Sundberg KM
Published: March 2009

Steel reinforced concrete is a widely used construction material. It is often the material of choice in bridges, parking garages, and marine structures because of its good durability and resistance to corrosion. However, over time, even well designed concrete is susceptible to chloride intrusion from deicing or marine salts or both, resulting in corrosion of embedded steel.

By the time corrosion of steel in concrete is readily noticeable, major repairs are often required. A nondestructive means of determining the corrosion rate of inaccessible steel is thus needed. Electrochemical techniques such as polarization resistance are useful, however resistivities of concrete range from 1000 to greater than 30 000 ohm-cm. Furthermore, reference electrodes are usually greater than 25 mm from the working electrode (rebars). Thus, large ohmic electrolyte resistance is present, even at the low current densities associated with steel in concrete, and must be accounted for to accurately measure corrosion rates.

In this paper we compare the use of current interruption correction for ohmic resistance to an electrochemical impedance measurement at 20 KHz. In general, we find a good correlation between the two techniques, and demonstrate that substantial ohmic resistances are present.
Settlement and Engineering Considerations in Landfill and Final Cover Design
Authors: Morris DV , Woods CE
Published: March 2009

Design of municipal landfills for closure is complicated by the large settlement that normally takes place for long periods of time after abandonment. This means that landfill slopes can change significantly with time, negating careful contouring and drainage provisions. It is possible to try and forecast this, but regulatory considerations (for landfills of specific depths especially) may hinder adequate design for full expected post-closure settlement. Preferred management techniques are outlined, and specific recommendations made for maintenance and settlement.
Field Measurements of Dynamic Moduli and Poisson's Ratios of Refuse and Underlying Soils at a Landfill Site
Authors: Sharma HD , Dukes MT , Olsen DM
Published: March 2009

This paper briefly discusses the applicability of laboratory and field test methods commonly used to determine the dynamic moduli and Poisson's ratio of undisturbed soil and rock and soil-rock fill and refuse fill materials. Down-Hole geophysical methods were used to measure dynamic shear and compression wave velocities of municipal refuse fill and the underlying soils at a sanitary landfill. These data are used to compute the in situ elastic and shear moduli and Poisson's ratio of the materials at the landfill site and are compared with values reported in the literature. Finally, conclusions are drawn regarding the use of dynamic moduli and Poisson's ratios obtained with the Down-Hole test method.
The Wak Test to Check the Increase in Soil Stiffness Due to Dynamic Compaction
Authors: Briaud J-L , Liu M-L , Lepert Ph
Published: March 2009

A test is proposed to check the increase in soil stiffness brought about by dynamic compaction. It consists of hitting the dynamic compaction weight, after it has been dropped by the crane and while it is resting on the ground, with an instrumented sledge hammer, recording the response of the weight through geophones simply placed on the weight. The analysis of the recorded signals gives the stiffness of the soil under the weight. The test is of very short duration and can be used after the weight has been dropped a number of times with the crane at one location to decide whether the soil has become stiff enough or if further compaction is necessary. The test is particularly useful for waste fills where other more conventional tests to check the increase in soil stiffness are very difficult if not impossible to perform.
Engineering and Compaction Characteristics of Boiler Slag
Authors: Acar YB , Seals RK , Puppala AJ
Published: March 2009

Engineering and compaction characteristics of boiler slag are presented. Laboratory and field compaction tests are conducted in assessment of these characteristics. Field tests are conducted on a slag fill of 0.92 m (3 ft) in thickness. A smooth drum vibratory roller 56 kN (12.5 kips) is used for compaction. The densification is evaluated after 2, 4, 6, 10 and 16 passes of this roller. A methodology is presented for estimating the lift thickness and the number of passes required for a desired level of densification.
Stability Considerations in the Design and Construction of Lined Waste Repositories
Authors: Mitchell JK , Seed RB , Seed HB
Published: March 2009

Safe disposal and storage of solid hazardous waste now requires the construction and filling of repositories underlain by multi-layer liner systems. These lining systems typically contain a large number of material interfaces, many of which have low shear strengths. This introduces potential failure surfaces along the side slopes and base of the fill mass which may control the overall stability of the overlying waste fill during fill placement operations. This paper discusses lessons learned from the investigation of the Kettleman Hills repository stability failure of March 19, 1988, regarding evaluation of the shear resistances along the different liner interfaces, the factors that control overall stability of the waste fill mass, and application of these lessons to analysis and design of safe repository filling operations.
Settlement of Municipal Refuse
Authors: Edil TB , Ranguette VJ , Wuellner WW
Published: March 2009

Refuse settlement in sanitary landfills is a complex process, which is dominated by secondary compression. Two mathematical models are used to model refuse settlement at four different sites. A data bank of empirical parameters was obtained and the trends observed.
Evaluation of the Stability of Sanitary Landfills
Authors: Singh S , Murphy BJ
Published: March 2009

In most of the major U.S. cities, both the capacity and availability of solid waste landfill sites are declining. One option for increasing landfill capacity has been to build landfills to greater heights and new sites are being planned to store refuse to unprecedented heights. This situation has raised concerns by many state and federal regulators regarding the stability of high refuse fill under static and dynamic loading conditions. This paper includes: ∎ a critical evaluation of the published and unpublished studies on the shear strength properties of refuse and settlement characteristics of refuse fills. ∎ a discussion of the inadequacy of the Mohr-Coulomb theory to account for the large, yet non catastrophic deformations that refuse undergoes. ∎ a presentation of a new approach to stability analysis based on the bearing capacity and settlement criteria of landfills ∎ an examination of the dynamic strength properties of refuse fills, including recently reported field shear wave data and a deformation analysis approach for evaluating stability when earthquake motions pass through a high landfill.
Slope Stability Investigations at a Landfill in Southern California
Authors: Siegel RA , Robertson RJ , Anderson DG
Published: March 2009

The results of geotechnical investigations and slope stability studies of an existing municipal/commercial landfill in southern California are presented and discussed. Investigations included cone penetration testing, installation and monitoring of inclinometers, piezometers, surface monuments, and laboratory classification and direct shear testing of refuse. The landfill was also monitored for dynamic response to earthquake-induced ground motions.
Case History: Use of the Cone Penetrometer to Calculate the Settlement of a Chemically Stabilized Landfill
Authors: Oakley RE
Published: March 2009

A waste fill containing chemically stabilized waste materials has been subjected to the overburden loading of a final cap for a period of over two (2) years. Prior to placement of the multicomponent cap, Cone Penetration Test (CPT) soundings were performed in the waste fill to determine the in situ condition of the materials. Settlement calculations developed from CPT and other data are compared to actual settlement survey data and discussions of the accuracy of the predictive method are presented.
Monitoring Landfill Movements Using Precise Instruments
Authors: Coduto DP , Huitric R
Published: March 2009

Investigations of landfill movements usually consist of measurements of settlement at the ground surface. This project consisted of installing instruments inside vertical borings drilled through a landfill in order to monitor both vertical and horizontal movements at various depths. Following two years of monitoring the data suggests that vertical strain rates are independent of depth while horizontal movements on slopes are greatest near the surface and diminish with depth. No permanent displacements occurred during a magnitude 6.1 earthquake.
Standards for the Playing Quality of Natural Turf for Association Football
Authors: Canaway PM , Bell MJ , Holmes G , Baker SW
Published: March 2009

For athletic fields used for soccer (association football), important components of playing quality include: ball rebound resilience, rolling resistance, traction (i.e., grip), and hardness. Other criteria related to, but not direct measures of, playing quality include surface evenness, grass cover, and water infiltration rate.

Standards of playing quality were developed on the basis of comparisons between players' perceptions of surfaces and the results of objective tests taken on the fields within 2 h of matches. Questionnaires were collected from 444 football players at 20 different fields. The fields were tested in the same locations within each field at six 5 by 5-m plots.

The results were used to formulate standards in the form of “preferred” and “acceptable” limits for each component of playing quality. The apparatus, test methods, and proposed standards for association football fields are described.
Standards for the Playing Quality of Artificial Turf for Association Football
Authors: Baker SW
Published: March 2009

In Britain, over 100 full-sized artificial playing surfaces have been installed for association football (soccer). Performance standards for the playing quality of artificial turf pitches (athletic fields) are required, and the development of different test methods is reviewed. For surfaces for soccer, it is necessary to consider both ball/surface and player/surface interaction. The principal techniques for testing surfaces used in Britain are ball rebound resilience, rolling resistance, traction/friction, sliding resistance, surface hardness (using Stuttgart and Berlin Artificial Athlete instrumentation), and the impact characteristics of a 5.5-kg head striking the turf.

Playing quality standards for soccer on artificial turf surfaces published in 1985 gave performance requirements for three levels of play. Classification to a national standard required ball rebound resilience in the range of 25 to 46%, ball deceleration of 0.45 to 1.5 m/s2, and a traction coefficient of 1.5 to 2.2. These limits are compared with data obtained from six natural turf pitches used by professional clubs covering a wide range of weather and pitch conditions. For ball rebound resilience and traction there was a reasonable comparability of the specified performance limits and the data for natural turf: the interquartile ranges were 31.7 to 44.4% for ball rebound resilience and 1.38 to 1.96 for traction. Some slight modifications to these performance limits are, however, proposed. For natural turf pitches, almost 90% of deceleration values were in the range 0.45 to 1.5 m/s2, but it was evident that values on artificial pitches, after the pile had been compacted by play, were not satisfying the threshold of 0.45 m/s2. Peak deceleration of a 5.5 kg headform after it had been dropped from 1.5 m was lower on natural turf surfaces than on artificial pitches. However, the values on the artificial pitches were comparable with those of safety tiles used as a playground surfacing.
Portable Apparatus for Assessing Impact Characteristics of Athletic Field Surfaces
Authors: Rogers JN , Waddington DV
Published: March 2009

This paper presents a method for quantitative assessment of the quality of athletic fields. Impact absorption characteristics were measured using the Clegg impact soil tester, the Bruel and Kjaer 2515 vibration analyzer, and three impact hammers (0.5, 2.25, and 4.5 kg). This apparatus was evaluated on sports fields and on research plots to obtain deceleration-time curves. The impact characteristics obtained from the curves were the maximum deceleration, time to maximum deceleration, duration of impact, rate of change of deceleration, surface deformation, severity index, and rebound ratio. After a series of experiments that evaluated the effects of turfgrass management practices on impact absorption characteristics, correlation coefficients between impact characteristics and between impact hammers were deter-mined. The correlation between the impact characteristics was higher when the evaluations were on one type of surface (turf) instead of multiple surface types (turf and soil). The weakest correlation was between the heaviest and lightest hammers.
Benefits of Testing for the Owners of Artificial and Natural Turf
Authors: Schefsky RJ
Published: March 2009

Testing of artificial and natural turf should be an integral part of the purchasing process to maximize the cost-effectiveness of the purchase of these sports playing surfaces. Subsequently, annual testing of the installed surfaces is necessary to ascertain and control the safety performance of these systems. An additional benefit is that hard numbers are generated which can be used to project the usable life of the sports playing surface. These projections are useful for budgeting considerations.
An Automated System for Field Testing and Soil Impact Analysis
Authors: Bregar MJ , Moyer WW
Published: March 2009

A sponsored effort was made to develop an automated system for determining the impact characteristics of soils and playing surfaces in situ. Most of the earlier measurements of this type yielded only information on peak deceleration. The equipment developed under this project consists of a portable measurement unit employed for data acquisition and a personal computer programmed for analysis of data from individual tests and for statistical analysis across an ensemble of tests. The data acquisition subsystem is comprised of an instrumented mass that is dropped from a fixed height through a guide tube and a battery-powered vibration analyzer that can capture the deceleration curve in memory for display or later recovery. The data set from each individual drop or averaged set of drops is downloaded to the computer and written to a Winchester drive. The analysis program uses a measured impact velocity and calculates maximum deceleration level, total duration of impact, several rates of change, and surface deformation. Recent additions to the program also provide determinations of severity index, rebound velocity, and rebound ratio when appropriate. The deceleration curve and all calculated parameter values are displayed on the system monitor; a hard copy of the display can be produced on a dot-matrix printer. A separate algorithm supports analysis of a set of data files selected by the operator; all selected files are combined into a single file on which statistical operations can be performed. Possible uses for the system include testing playing surfaces for injury potential and regular diagnostic testing of surfaces which must be maintained in a specific condition. The system uses widely available processing equipment and only the drop unit itself is custom made.
Laboratory Measurements of Impact Absorption on Turfgrass and Soil Surfaces
Authors: Henderson RL , Waddington DV , Morehouse CA
Published: March 2009

Soil and turfgrass surfaces prepared in wooden boxes were evaluated in the laboratory for peak deceleration and depth of penetration using Procedure A of ANSI/ASTM Test for Shock Absorbing Properties of Playing Surface Systems and Materials (F 355-86). A 9.1-kg missile with a flat surface (129 cm2) was dropped three times from a height of 61 cm. The peak deceleration was greater and the penetration depth less with a soil depth of 7.5 cm than with depths of 15 cm or greater. This effect was attributed to the box bottom and heavy anvil on which the boxes were placed for testing. Peak deceleration was lower and penetration depth greater with turf cover than with bare soil and when soil was core cultivated. Each successive impact altered the results because of soil compaction. The limitations of this method were the small surface area (20 by 47 cm) available for testing (only three impact locations per box) and the lifting and transporting of soil-filled boxes.
Effects of Management Practices on Impact Absorption and Shear Resistance in Natural Turf
Authors: Rogers JN , Waddington DV
Published: March 2009

The Clegg impact soil tester (0.5 and 2.25-kg hammers), the Bruel & Kjaer 2515 vibration analyzer, and the Eijkelkamp Type 1B shear vane were used to evaluate effects of soil compaction, aeration, soil moisture, and thatch on impact absorption and shear resistance characteristics in several turfgrasses. Impact absorption characteristics were influenced most by soil moisture, soil compaction, and thatch. Peak deceleration decreased with increasing soil moisture and increased with compaction. Effects from aeration on peak deceleration were usually not significant; however, on several dates aeration significantly decreased the severity index and increased deformation. The presence of thatch on a surface improved shock attenuation under most conditions. Compaction increased shear resistance values. The effects on shear resistance from aeration and soil moisture were varied.
Feasibility Assessment of Randomly Oriented, Interlocking Mesh Element Matrices for Turfed Root Zones
Authors: Beard JB , Sifers SI
Published: March 2009

Turfgrass injury and reduced playing surface quality are increasing problems on intensively trafficked turfs such as sports fields and race courses. Feasibility investigations were conducted concerning the use of randomly oriented, interlocking mesh element root zone matrices for the purpose of providing reduced divoting, better soil-turf stabilization, increased traction, and improved uniformity of ball bounce. Mesh element inclusion substantially reduced divot opening width and length and lateral cleat tear. This resulted in twice as rapid divot recovery. The mesh element matrices had no effect on ball bounce resiliency, but substantially enhanced the consistency of ball bounce. The traction and compression displacement results were variable. Soil moisture levels were consistently higher in the mesh element matrices treatment. This feasibility investigation revealed that augmentation with mesh element inclusions provided significant benefits in reduced turfgrass injury and a more uniform playing surface.
Recent Progress and Issues on Inerts Testing
Authors: Curcio LN
Published: March 2009

The issues surrounding inerts testing have become some of the highest profile issues affecting pesticide formulations today. Most agree that the Environmental Protection Agency (EPA) has been correctly concerned about the lack of toxicity data for various inert components used in pesticide formulations. In many cases this concern is justified; however, in an equal number of cases, a great deal of data exists which needs to be provided to EPA in an orderly manner. This will enable suppliers to assure formulators of a continuing supply of acceptable inert materials for their future use. The following discussion will focus on several aspects of the regulations which have become apparent as the industry moves forward in understanding and implementing the new pesticide procedures. These aspects include testing requirements, animal considerations, and state versus federal requirements.
Evaluation of Cyclodextrin Complexes of Pesticides for Use in Minimization of Groundwater Contamination
Authors: Dailey OD , Dowler CC , Glaze NC
Published: March 2009

Recently, concern over the contamination of groundwater by pesticides has mounted. The cyclodextrin complexes of a number of pesticides most frequently implicated in groundwater contamination have been prepared.

Initial pesticide efficacy studies have been conducted using conventional application technologies with various preemergence herbicides (as both commercial formulations and cyclodextrin complexes) under greenhouse conditions. The leachability and persistence of the newly formulated herbicides in the soil profile were also measured utilizing bioassay indicator crops in the analyses. Cyclodextrin formulations of atrazine and simazine were prepared only under forcing conditions and had very low levels of biological activity. A cyclodextrin formulation of metribuzin was somewhat less active than the commercial formulation, possibly as a result of controlled release properties.
Evaluation of Airborne Dust Measurement Methods for Agricultural Chemical Carriers
Authors: Raymond ML
Published: March 2009

Due to the environmental and safety concerns in the manufacturing and handling of toxic chemicals on inert carriers, the determination of the airborne dust from such materials is of interest. Therefore, a variety of airborne dust measurement methods have been studied to determine which ones are best suited for determining the dustiness of agricultural chemical carriers, and possibly serve as the basis for an ASTM standard procedure. The measurement techniques evaluated include light absorption, light scattering, gravimetric, and a charge transfer technique. The methods were evaluated for the following characteristics: ease of use, reliability, equipment required, sensitivity, and reproducibility. Descriptions of the equipment and techniques along with data are presented. Comments are made as to the appropriateness of the methods for determining airborne dust or comparing the dustiness of various carriers.
Effect of Spray Deposit Characteristics on Insecticide Efficacy
Authors: Luttrell RG , Smith DB
Published: March 2009

Dosage, droplet size, deposit density, and tank-mix concentration are spray deposit characteristics which may influence the efficacy of insecticides. The relative influence of each of these variables on insect control is difficult to measure because of the interrelationships among the variables. Only a few experiments have actually attempted to quantify the relative influence of all of the spray deposit variables on insecticide efficacy. An indirect approach to estimating the relative influence of these variables on efficacy of insecticides for control of Heliothis spp. larvae on cotton was developed and tested over the past 5 years at Mississippi State University. Results suggest that dosage is more important than the other deposit variables in influencing Heliothis spp. control on cotton. Implications of these results and limitations to current research approaches are examined in this paper.
Soil Organic Matter Sensing for Precision Herbicide Application
Authors: Sudduth KA , Hummel JW , Funk RC
Published: March 2009

A prototype sensor which used near infrared (NIR) reflectance techniques to determine the organic matter content of the surface layer of soil was developed and was tested both in the laboratory and in the field. Laboratory predictions yielded an r2 of 0.89 and a standard error of prediction of 0.23% organic carbon (0.40% organic matter) with 30 representative Illinois soils. Limited in-furrow field operation of the sensor produced a much higher standard error (0.53% organic carbon), due to the movement of the soil past the sensor as scanning was accomplished. Although improvements in sample presentation techniques are required before the sensor can be used in real-time field operation, the current configuration could provide rapid, on-site organic matter determination for mapping and subsequent application rate control using a positioning system.
On-the-Go Application of Dry and Liquid Herbicides with Granular Fertilizer
Authors: Leedahl AO , Strand GL
Published: March 2009

On-the-go application of dry and liquid herbicides with dry granular fertilizer is a successful commercial reality. Liquid herbicide is coated on dry granular fertilizer in a patented process in the boom tube of a pneumatic applicator. The process takes a fraction of a second, it greatly reduces herbicide contamination of handling equipment and simplifies clean up. Dry granular herbicides are metered individually into each boom tube and blended with dry granular fertilizer on-the-go.
Pesticide Delivery Systems: Spray Distribution and Partitioning in Plant Canopies
Authors: Hall FR , Reed JP , Reichard DL , Riedel RM , Lehtinen J
Published: March 2009

Considering only a small fraction of pesticidal sprays reaches the target, more attention needs to be placed on developing techniques which increase crop canopy penetration. Quantification of where pesticides are going is clearly going to be emphasized by EPA as a mandatory process for all future registrants. Drift represents a loss of chemical and implies dangers of air and water pollution. A critical problem is orchard airblast sprayer applications. Plant coverage by 3 boom sprayers was evaluated on tomatoes. Partitioning and overall canopy distribution, was measured by % area covered via image analysis. Similiarly, partitioning and distribution of sprays from a modified airblast sprayer was evaluated using water sensitive paper. On field grasses, paraquat applied at recommended field rates was used to measure efficacy and drift damage with the electrostatic nozzle charged vs. a conventional hydraulic nozzle. In short grass, charged was superior to uncharged whereas in long grass, both were superior to other treatments. In the laboratory, drift was reduced by 99.0% by shrouding and charging electrostatic (ENS) nozzles. The ramifications of sampling method, distribution inconsistencies, and biological effects are discussed. These results in combination with capture efficiency studies will allow future studies on spray accountancy to proceed in accordance with EPA SOP standards (40CRF, 158.142).
Off Target Pesticide Losses Resulting from the Use of an Air-assisted Orchard Sprayer
Authors: Riley CM , Wiesner CJ
Published: March 2009

This report details the off-target spray losses resulting from the application of five insecticide sprays to an orchard using a Good Boy ®air assisted sprayer. Off-target deposition on the ground was assessed using a number of flat plate collectors placed at distances up to 200 m downwind of the orchard. Time integrated airborne spray flux was measured using Rotorods® and a novel array of sampling wires. The results are discussed and used to produce regression equations from which realistic worst case deposits are predicted.
Effect of Sprayer Bounce and Wind Condition on Spray Pattern Displacement of Two Agricultural Nozzles
Authors: Krishnan P , Herrera J , Kemble LJ , Gottfried S
Published: March 2009

Effect of sprayer bounce and wind velocity on spray pattern displacement (SPD) of two agricultural nozzles were studied using an experimental spray patternator. Tests were conducted at a nozzle pressure of 207 kPa at two wind conditions (C, crosswind velocity of 2.68 m/s; and CH, combination of crosswind velocity and headwind velocity of 2.63 m/s) and at two sprayer bounces (0.2 and 0.4 m amplitude at a frequency of 1 Hz).

Sprayer bounce × wind velocity had significant effect on the SPD values. For both the nozzles, the SPD value for sprayer bounce (0.4 m amplitude) × crosswind velocity × headwind velocity was higher by at least 5 percentage points than that for sprayer bounce (0.4 m amplitude) × crosswind.
Subsurface Injection of Turfgrass Insecticides
Authors: Ozkan HE , Reichard DL , Niemczyk HD , Klein MG , Krueger HR
Published: March 2009

Surface application of insecticides on turfgrass for control of many subsurface grubs is not very efficient. It can be potentially hazardous to people, pets and other animals exposed to the insecticides. To reduce this danger, three injection systems were developed to place insecticides below the turf surface and into the main zone of activity of the grubs. The results indicate that insecticides can be successfully injected with little damage to the turf. Analyses of surface residues after injection of two common turfgrass insecticides showed significant reductions ranging from 38 percent to 95 percent over the amount remaining from spraying on the surface. Grub control using two of the three injection methods was equal to or better than that achieved with the conventional surface application method. Although it satisfactorily injected the insecticide, the third injection method using a rolling point applicator was not evaluated for grub control because the preliminary data showed little dispersion of insecticide from the point of injection and indicated a low probability of achieving efficient and effective control.
Toughness Models of Whisker-Reinforced Ceramic Matrix Composites
Authors: Chiang Y-C , Chou T-W
Published: March 2009

This paper presents a theoretical investigation of the critical strain energy release rate, Gc, of whisker-reinforced ceramic matrix composites. Crack deflection is considered as the major energy dissipation mechanism in fracture. The modeling of crack deflection is conducted based on a determination of the path of advancement of the deflected crack front along whiskers. The knowledge of crack path provides the basis for evaluating the deflection-induced reduction in strain energy release rate. The theoretical predictions are compared with experimental data of silicon-carbide (SiC) whisker-reinforced Al2O3 composites.
Monotonic and Cyclic Behavior of a Silicon Carbide/Calcium-Aluminosilicate Ceramic Composite
Authors: Rousseau CQ
Published: March 2009

A preliminary investigation of the mechanical behavior of a Nicalon/CAS [O/90]2s laminate at 20 and 815°C has been performed For monotomc and cyclic tension, a sequence of progressive damage has been identified as 90° ply degradation, followed by transverse matrix cracking in the 0° plies and nonlinear strain deformation. Monotonic and cyclic behavior at 815°C was degraded due to embnttlement of the fiber/matrix interface. Longitudmal stiffness remained fairly constant following initial degradation on the first fatigue cycle. Surface crack density and inelastic strain deformation were found to be functions of applied stress and, thus, useful in monitoring damage progression. At 20°C ultimate strength increased, and stram-to-failure decreased, following cyclic damage. For uniform umaxial tension, Nicalon/CAS behaves in a manner amenable to evaluation by the critical element method of fatigue life analysis.
Mechanical and Thermal Properties of Silicon-Carbide Particle-Reinforced Aluminum
Authors: Schmidt K , Zweben C , Arsenault R
Published: March 2009

Increasingly stringent structural and electronic packaging requirements have exceeded the capabilities of traditionally used metallic materials in many applications. Metal matrix composites (MMCs) are potential replacements. Silicon-carbide particle-reinforced aluminum (SiCp/Al) is an attractive candidate because of its excellent mechanical properties, tailorable coefficient of thermal expansion (CTE) and high thermal conductivity. At present, there is very limited property data available for this material. This paper presents material properties of selected SiCp/Al composites, evaluated at the General Electric Astro Space Division, including a discussion of the test methods used in their evaluation.
Ceramics Tensile Grip
Authors: Larsen CG
Published: March 2009

Minimizing bending strain in tension tests has become increasingly important over the last few years with the advent of testing very brittle materials such as ceramics. There are many different ways to minimize bending strain m a tension test, but the most popular method is to allow the grip ends to move freely, or float.

This paper discusses a new tensile grip that uses a captive volume of oil to support the tensile load applied to the specimen. The portion of the grip that is attached to the specimen is allowed to float on a captive volume of oil so that very little bending moment is applied to the specimen. Other factors that contribute to bending stress are discussed in relation to achieving a tension test with a minimum of bending strain.

Data is presented showing the capability of the grip. This data has been manipulated to differentiate between the bending strain caused by the grip versus the bending strain caused by eccentricities within the test specimen. The results are shown as percent bending strain of axial strain versus axial load.

This paper discusses the function, logistics of use, and experimental test results of this new tensile grip. The results show that this grip is capable of producing accurate test results with even very brittle materials.
Influence of Size Distribution on Droplet Mean Diameter Obtained by Ensemble Light Scattering
Authors: Presser C , Gupta AK , Dobbins RA , Semerjian HG
Published: March 2009

Measurements with a phase/Doppler interferometric (PDI) single-particle-counting system and the ensemble light-scattering/polarization ratio (ESPR) technique have been carried out in a kerosene spray, introduced vertically upwards into coflowing nonswirling and swirling air flow fields. The droplet mean sizes, determined using the ensemble technique, were found to be smaller than those obtained with the PDI system. Determination of the Sauter mean diameter (D32) for each technique is based on different assumptions which may have an influence on the results. One assumption for the ensemble light-scattering measurements is the form of the droplet size distribution, which in this case incorporates a monomodal log-normal distribution function (LNDF) of prescribed skewness. Measurements taken with the phase/Doppler system have indicated the presence of both positively skewed monomodal profiles with long tails (along the centerline) and bimodal distributions (near the spray boundary). Our results indicate that the LNDF can adequately represent monomodal size distributions found near the spray centerline. Near the spray boundary, the combination of two monomodal log-normal distribution functions is used to represent the measured bimodal size distributions.

To investigate the effect of size distribution on the measurement of droplet size, several different monomodal distribution functions with varying degrees of skewness were examined, as well as a bimodal distribution function. Calculations for the ESPR technique using a log-normal distribution function are evaluated with measured PDI size distributions, and the dependence of polarization ratio on D32 is examined. The results indicate that the geometric mean diameter and the complex refractive index have a significant influence on the polarization ratio, while the geometric standard deviation and the integration limits in droplet size have a small effect. The polarization ratio, however, does not change dramatically if the value of these parameters is kept within the range of interest and the assumed size distribution remains similar to that measured. Therefore, the differences in the measured droplet size cannot be solely attributed to the uncertainties in the size distribution.
Droplet Sizing Interferometry
Authors: Jackson TA
Published: March 2009

Interferometric techniques, which use information encoded in the Doppler burst resulting from the interaction of a particle with a two-beam interference pattern have become practical diagnostic tools for the analysis of complex, two-phase flows. In the original application of these techniques to sprays, the signal visibility, a measure of the modulation of the scattered light intensity, was analyzed to determine the size of the particle. Light collection was made on-axis, using the diffracted portion of the scattered light. The particle shape was a secondary consideration, and its index of refraction was not required in the analysis. On-axis collection, however, restricted application of the technique to flows of impractically low particle number density. Off-axis collection of the refracted component of the scattered light represented a significant refinement to the original method. However, with this approach, the particle to be sized had to be spherical and its index of refraction had to be known a priori. With this refinement, application to practical number density flows became possible, although the collection efficiency remained adversely affected by high particle loading. The final major development came when the basis of the interferometric measurement changed from visibility to phase shift. The phase shift approach has the advantages of the off-axis visibility technique and also has a broader sizing dynamic range and is less sensitive to the droplet number density. The technique has so markedly improved droplet measurements that extensions of the technique to measure liquid mass flux and local droplet number density are being evaluated. This paper traces the technical evolution of the interferometric particle sizing. It also examines the capabilities of the current approach in making two-phase flow measurements in complex flows.
Phase-Doppler Measurements Near the Nozzle in a Low-Pressure Water Spray
Authors: Sellens RW
Published: March 2009

Phase-Doppler measurements of drop size and velocity were made in a spray of water from a swirl jet oil burner nozzle, operating at pressures from 207 to 345 kPa. These drop-size and velocity distributions, taken in the near field, are a direct reflection of the characteristics of the breakup process, because the surrounding gas stream has had little effect on the newly formed drops. The experimental results agree well with the predictions of the breakup process made using the maximum entropy formalism in conjunction with physical constraints dictated by the laws of conservation.