bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrasonic Agitation Method for Accelerating Batch Leaching Tests
Authors: Caldwell RJ , Stegemann JA , Chao CC
Published: March 2009

A method has been developed which uses ultrasonic cavitation to accelerate batch leaching tests. Batch leaching tests, in which attainment of an equilibrium between the solid sample and liquid leachant is desired, usually involve particle size reduction and mixing to hasten mass transfer of soluble compounds. In the study discussed here, mixing in the form of ultrasonic cavitation was used to supply an intense level of agitation. Breaking the liquid boundary layer surrounding individual waste particles ensured a maximum concentration gradient between the solid and liquid phases and accelerated attainment of steady state concentrations.

Evaluation of the acceleration technique was made through comparison of leachate quality of stabilized/solidified (S/S) residue samples tested using the Wastewater Technology Centre's (WTC) equilibrium extraction (EE) and an ultrasonically agitated version of the same test method (UEE). The sample preparation, liquid-to-solid ratio, extraction fluid, etc., specified in the EE method were held constant for the EE and UEE samples, while the duration and method of agitation was altered for the UEE samples. To date, this evaluation has been made using five metal finishing residues, which were selected based on their elevated concentrations of regulated contaminants. The results of the evaluations are presented and suggestions are made as to the applicability of this accelerated test method.
Recycling Contaminated Spent Blasting Abrasives in Portland Cement Mortars Using Solidification/Stabilization Technology
Authors: Salt BK , Garner AG , Fowler DW , Loehr RC , Carrasquillo RL
Published: March 2009

The use of abrasive blasting to remove paint containing lead, cadmium, and chromium from steel bridges is producing contaminated spent blasting abrasives that may be classified as hazardous by the Environmental Protection Agency based upon toxicity. Under such a situation, the transportation and disposal of the spent abrasives is difficult and costly. A potentially inexpensive and practical solution to this problem is to recycle the contaminated spent blasting abrasives at the construction site in an environmentally safe manner using solidification/stabilization technology. This research investigates the use of portland cement to solidify/stabilize the spent abrasives and produce a usable construction material.
Laser Driven Thermal Reactor for Hazardous Waste Stabilization
Authors: Nazarian A
Published: March 2009

The method for development of technology of hazardous waste stabilization on a strong research base and for determination of parameters and conditions of appropriate processes is presented herein. It has been demonstrated on multiphase systems to find corresponding parameters and conditions.
Field Quality Control Strategies for Assessing Solidification/Stabilization
Authors: Butler SM , Barth EF , Barich JJ
Published: March 2009

Existing regulatory mobility reduction (leaching) tests are not amenable to real time quality control because of the time required to perform sample extraction and chemical analysis. This is of concern because the leaching test is the most important parameter used to relate treated waste performance to public health and environmental protection goals. To help alleviate this problem, an integrated quality control approach is recommended in which the number of leaching tests performed is minimized and quality control is maintained by a program which includes monitoring material (reagent) quality and equipment calibration, personnel requirements, real time testing, pilot cell demonstrations, and early failure indicators.
Endocrine Issues Update
Authors: Duggan AJ
Published: March 2009

There is growing controversy that low-level exposures to chemicals and pesticides have caused increased incidences of reproductive system cancers, developmental abnormalities and physical deformities in wildlife and humans. Substances that cause these effects are called endocrine disrupters. The science to address endocrine issues is still developing, but poignant publications, such as Theo Colborn's Our Stolen Future, have fueled the controversy and increased public awareness about endocrine issues. EPA recently issued the “Special Report on Endocrine Disruption: An Effects Assessment and Analysis Document.” The report concluded that environmental contaminants can adversely affect animals and wildlife, but more research is warranted to determine the causal relationship between exposure and adverse health effects in humans. In August 1996, Congress enacted legislation that directed EPA to implement, by August 1999, a screening and testing program to evaluate chemicals and pesticides for endocrine effects. In October 1996, EPA convened a Federal Advisory Committee, EDSTAC (Endocrine Disrupter Screening and Testing Advisory Committee), of stakeholders and scientists from various activist groups, government and industry to assist them in the process.
The Regulatory Role of the Applicator in Developing, Approving, Using, and Monitoring Pesticides
Authors: Beck JR , Martin LR , Giles RH
Published: March 2009

Pesticide Applicators are responsible to Federal, State and local agencies for label compliance and responsible to property or residence owners for effective results on a site specific area. Pesticide Applicators have much responsibility and years of practical field experience but as a group are rarely involved in the process of establishing pesticide policy, regulations or efficacy research from which our labels are written. Equally disturbing is the legal void for solving complex, multifaceted pest problems that more frequently are impacting entire communities.

The regulatory and private research bureaucracy needs to look outside of themselves to develop a partnering relationship with the current generation of qualified Pesticide Applicators. Anything less would squander a vast pool of experiential knowledge that is vital to the healthy growth of our society in the new millennium.
Pest Control with Sprays — A Look into the Past and a Glimpse of the Future
Authors: Wolf TM
Published: March 2009

The application of liquid sprays remains the foremost means of delivering agents to control insect, disease, and weed pests of major crops. Since the introduction of crop protection agents (CPAs), it has repeatedly been shown that the method of spray application has an impact on the resulting product effectiveness, yet relatively little systematic progress in achieving the optimum spray deposit has been made. Instead, because of the heterogeneous spatial and temporal nature of most pest complexes, specific optimizations have largely been abandoned in favor of general sprays which compromise spray drift, canopy penetration, retention, and efficacy. New atomization technologies offer opportunities to change droplet size and carrier volume independently, on-the-go. This is expected to renew interest in the optimization of spray quality in a site- or case-specific fashion. Initial implementation of this capability will revolve around variable rate application and drift management. In the long run, however, there will be a new demand for information relating spray quality to canopy penetration, spray retention, and efficacy for a range of conditions, pests, active ingredients, and formulations. Incorporation of additional information will no doubt increase registration costs and product label complexity. Still, the industry's response to these opportunities will determine, to a large degree, how application technology will contribute to our society's overall goals of reduced use and increased efficiency of pesticides.
Surfactants Differ in Their Effect on Droplet Retention, Droplet Spread, and Herbicide Efficacy
Authors: Manthey FA , Woźnica Z , Miłkowski P
Published: March 2009

Spray solution must be retained by the leaf before foliar absorption of an herbicide can occur. Once retained, spray droplets can spread on the leaf surface. Experiments were conducted in the greenhouse to determine the effect of twelve surfactants on spray droplet retention, droplet spread, and efficacy of glyphosate [N-(phosphonomethyl) glycine] and imazethapyr {2-[4,5-dihydro-4-(1-methylethyl-5-oxo-1H-imidazol-2-yl]-5-ethyl-3-pyridinecarboxylic acid}. Green foxtail (Setaria viridis) and barley (Hordeum vulgare) were the bioassay species. Spray droplet retention, droplet spread, and herbicide efficacy varied with surfactant. Surfactant enhancement of spray retention did not relate with droplet spread for either herbicide or plant species, nor did spray retention relate with glyphosate or imazethapyr efficacy for green foxtail and barley. Further, efficacy of glyphosate and imazethapyr on green foxtail and imazethapyr on barley did not relate with droplet spread. Glyphosate efficacy on barley generally increased as droplet spread decreased. However, the lack of droplet spread did not always result in a high level of surfactant-enhanced glyphosate efficacy.
Spreading Mechanisms of “Superwetters” on Hydrophobic Surfaces
Authors: Nikolov AD , Wasan DT , Koczo K
Published: March 2009

Advanced optical techniques, such as differential and common three-phase contact angle interferometry, were developed to monitor simultaneously the meniscus profile, the microscopic three-phase contact angle dynamics, and the wetting film thickness stability during the spreading process of aqueous drops containing polyoxyethylene trisiloxane, 8EO, the so-called “superwetter” (“superspreader”) on solid surfaces. The microscopic observations showed that the superspreading process goes in three stages on hydrophobic solid surfaces. The first stage is driven by the low air/aqueous solution surface tension and the drop will spread first on the solid surface until mechanical equilibrium is reached. In the second stage the drop surface area at the three- phase contact region is stretched and the spreading is driven by the surface tension gradient. The maximum of the lateral velocity of the surface points depends on the local meniscus thickness, viscosity of the fluid at this thickness and the surface tension gradient. Due to the difference in the lateral velocity of the surface points a “bump” is formed at the front of the spreading liquid. In the third stage of the superspreading process the bump breaks into droplet “crowns” and after a while these droplet crowns begin to slide on the solid surface.
Methyl Vinyl Ether Maleic Acid Half Ester Copolymers as Dispersing Agents in Aqueous Flowable Formulations
Authors: Curry JF , Goehner R , Narayanan KS
Published: March 2009

Aqueous-based flowables have been studied using methyl vinyl ether monoalkyl maleate copolymers as anionic dispersing agents for pesticides such as atrazine, carbaryl, and chlorothalonil. These polymers have received EPA exemption for use in crop protection and on animals. The polymer types, which differ in the length of the alkyl ester side chain, or contain a carboxylic acid instead of the monoester with appropriate neutralization, were each paired with either nonionic or anionic surfactants, such as nonylphenol ethoxylate, tristyryl phenol ethoxylate, or N-methyl taurate, in water-based suspension concentrates. Physical-chemical data show these anionic polymers, new for agricultural applications, can be used to make stable dispersions with different pesticides under varying conditions of hard water. Prototype formulations and comparative stability data with commercial formulations are provided. A working model is used to explain the role of the polymers in stabilizing dispersions.
Developing Emulsifiable Concentrate Formulations Using Droplet Size and Experimental Design Software
Authors: Butler BJ , Schultz AK
Published: March 2009

The objective of this paper is to study the development of emulsifier blends for EC formulations using Design-Expert software, using emulsion droplet size as the measured response. Particle size was measured using the NICOMP Model 370 Submicron Particle Sizer from NICOMP Particle Sizing Systems. The emulsifier systems optimized were 3 component blends of calcium dodecylbenzene sulfonate, an EO/PO block copolymer, and a nonionic surfactant. The test systems were permethrin and chlorpyrifos insecticides.

The models developed for both systems, and the statistical details are reviewed. The advantages and disadvantages of using statistical Design of Experiments (DOE) with particle size analysis are discussed.
Fatty Methyl Esters as Solvent Alternatives for Emulsifiable Concentrate Formulations
Authors: Skelton PR , Turpin KL
Published: March 2009

Aromatic petroleum hydrocarbons have been selected as the solvent of choice in many pesticide emulsifiable concentrate formulations. These solvents have primarily been utilized because of their stable physical properties and cost effectiveness. Historically, fatty methyl esters have been used to increase solubility, improve stability, and increase flash points in some high active pesticide formulations.

In an attempt to investigate solvent alternatives in emulsifiable concentrate formulations, fatty methyl esters were examined under laboratory conditions with a cross section of typical fatty methyl esters. Emulsifiable concentrates consisting of chlorpyrifos, diazinon, trifluralin, and malathion were used in this study. Fatty methyl esters ranging in carbon chain lengths C4 - C18 were evaluated as replacements for C10 alkylbenzene solvent (aromatic solvent) in the emulsifiable concentrate formulations. The emulsification properties were compared. This study examines the effect on emulsification of each pesticide utilizing fatty methyl esters versus aromatic hydrocarbon solvent.
Dearomatized Tailor Made Hydrocarbon Fluids in Pesticide Formulations
Authors: Frisch PD , Verbelen RA
Published: March 2009

In a previous study, the effect of specific dearomatized hydrocarbon fluids with boiling ranges between 220 and 310 °C was highlighted. In combination with surfactants, they were shown to increase significantly the performance of active ingredients (insecticides and herbicides) when incorporated in pesticide formulations or in tank mixes. These fluids were shown not only to improve the biological activity of the active ingredients but also to modify the application properties, volatility versus penetration characteristics and the mode of action.

This paper represents an extention of that prior work and focuses on the contribution of a specific dearomatized tailor made fluid boiling in the 240 – 260 °C range to the efficacy enhancement of two widely used herbicides, acetochlor and acifluorfen. Acetochlor, a selective pre-emergent herbicide used to control annual grasses in maize, was formulated into capsule suspension (CS), microcapsule and emulsifiable concentrate (EC) formulations. Acifluorfen, a post-emergent herbicide used to control annual broad leafed weeds in soybeans, was formulated into microemulsions (μE) and soluble concentrate (SL) formulations.

It will be demonstrated that capsule suspension and microemulsion formulations of these two active ingredients incorporating a tailor made hydrocarbon fluid provide improved or similar weed control with reduced phytotoxicity.
Methodology for Evaluation of Glyphosate Formulations
Authors: de Ruiter H , Meinen E , Uffing AJM
Published: March 2009

The objective of the study was to develop a simple procedure for the evaluation of glyphosate formulations. Surfactants are included in glyphosate formulations for improving the wetting of the leaf surface and enhancing the foliar uptake of the herbicide. Black nightshade (Solanum nigrum L.) and wheat (Triticum aestivum L), species differing greatly in wettability and uptake properties, were used for measuring the influence of three surfactants (Ethomeen T/25, polyoxyethylene (15) tallow amine; Atplus 201, polyoxyethylene (20) hexitan monolaurate ester, Sisterna L70-C, sucrose laurate ester) on dose-response relations. The unformulated isopropylamine salt of glyphosate was used and surfactants were included at 0.25% (w/v).

The ED50 values for glyphosate applied on black nightshade and expressed as g ae/ha were 71 (no surfactant), 4 (Ethomeen T/25), 4 (Atplus 201), and 39 (Sisterna L70-C). With wheat the ED50 values for glyphosate were 300 (no surfactant), 15 (Ethomeen T/25), 12 (Atplus 201), and 28 g ae/ha (Sisterna L70-C). With both species, but particularly with black nightshade, the surfactant Sisterna L70-C was less effective than Ethomeen T/25 and Atplus 201.

Spray retention and foliar uptake experiments indicate that in wheat the surfactant-induced spray retention (up to 3-fold) is the predominant factor explaining the influence of the surfactants on glyphosate phytotoxicity. In black nightshade, the surfactant-induced foliar uptake of glyphosate (up to 6-fold) was considered as the factor explaining the enhanced phytotoxicity of glyphosate. In both species, the surfactant Sisterna L70-C did not promote foliar uptake of glyphosate. We conclude that the influence of the surfactants on the ED50 in the two species roughly indicates the potency of these compounds to enhance spray retention and foliar uptake.
Surfactant Phytotoxicity to Barley Plants and Calli
Authors: Manthey FA , Dahleen LS
Published: March 2009

Surfactants are used in pesticide and spray adjuvant formulations. Unfortunately, some surfactants are phytotoxic and can inhibit pesticide efficacy. Experiments were conducted in the greenhouse and laboratory to determine the phytotoxicity of surfactants that differed in lipophilic chemistry and/or hydrophilic:lipophilic balance (HLB). Barley (Hordeum vulgare L.) was the bioassay species. Foliar injury generally was greater with low than high HLB surfactants when surfactants were applied based on weight/volume but not when applied based on molar concentration. Lipophilic chemistry, HLB, and concentration influenced the surfactant effect on droplet spread, plant transpiration, and proton extrusion from barley calli. Surfactants reduced or had no affect on transpiration 1 h after application. Transpiration recovered to original levels 24 h after application, if no foliar injury occurred. Most surfactants at 0.01 mM reduced proton extrusion from barley calli. Simple relationships were not observed between foliar injury and droplet spread; foliar injury and transpiration; droplet spread and transpiration; or foliar injury and proton extrusion.
Building Data Management
Authors: Chadwick JJ
Published: March 2009

An adaptation of UNIFORMAT II (ASTM E 1557) and MasterFormat used in conjunction with the list of rooms yields a hierarchical data structure that provides a relevant address for virtually every consideration of building data This method of organizing information can be used to format new reports as well as organize existing physical files.
“Suggested Standards for Glass Fiber-Optics Functional Architectural Lighting in Historic Buildings and Sites”
Authors: Kay GN
Published: March 2009

Mechanical/electrical systems, upgraded or installed anew, can have a serious mpact on historic structures and their contents. Since these disciplines are necessary to satisfy building codes and current tenants' requirements, minimum standards of procedure are essential, because, if done insensitively, this work can cause untold aggravation, horrendous cost overruns and even irreversible damage to original design and fabric. Two of these services are especially destructive to the fugitive organic materials found in most pre-1940 properties. They are unbalanced temperature/humidity levels, and light. Obviously, light is necessary to experience all human endeavors, but, whether manmade or natural, it will eventually cause deterioration from infrared and ultraviolet rays. One type of lighting can delay these inevitable effects. That is the completely different concept of glass fiber-optics functional architectural lighting. This paper offers criteria for employing this very energy-efficient, low maintenance, and discreet lighting tool to extend the life of architectural heritage.
Non-Destructive Determination of the Penetration Depth of Impregnation Materials
Authors: Pleyers G , Sasse HR
Published: March 2009

For the quality control of preservation methods using impregnation materials on porous building materials it is necessary to know the penetration depths of these materials. A simple new method and equipment for the non-destructive determination of the penetration depth of impregnation materials was developed. Based on the more than thirty year old “Karsten-tube” method and making use of the correlation between the penetration depth and the impregnation material absorption per area, the new method is suitable to adequately determine the penetration depth both in laboratory and in-situ.
Balk at Caulk - Guidelines for Repair of Joints in Historic Stone
Authors: Sherwood SI
Published: March 2009

For structures unsheltered from rain and snow - such as monuments, bridges, tombstones, standing ruins - water in stone is a recurring, perhaps constant, condition. Therefore, rather than attempt to exclude water from historic masonry, the preservation goal should be to manage moisture movement, with emphasis on facilitating runoff and evaporation. Evaporation is an important mechanism for moisture egress, and the larger the area of the evaporative surface, the more efficient the removal of moisture. As joints between individual stone blocks function as micro-scale storm sewers, sealing open joints with elastomeric sealants may temporarily facilitate runoff, at the same time restricting evaporation. Impermeable joint materials in masonry structures without overhanging roofs or other water-diversionary tactics will trap the inevitable water within the masonry units, leading to biological decay and disaggregation of mineral matrices. In-kind replacement of mortar (25–50 years service) and lead (75–100 years service) are viable alternatives to sealants (5–10 years service) for joint repair in historic stone. The traditional materials are cost competitive with sealants, particularly if scaffolding costs are included in life-cycle estimates. There are very few, if any, cases of historic masonry where sealants are appropriate substitute materials for mortar or lead.
Practice and Research: The Need for Standards for Historic Mortars
Authors: Fontaine L , Thomson ML , Suter GT
Published: March 2009

A mortar research program for the Public Works and Government Services of Canada was initiated in the late 1980's. This research program was a most comprehensive one on the Canadian level; more than 100 mortars were tested in the course of the last decade. Its primary objective was to identify durable repointing mortars which would be practical in their application and compatible with specific traditional stone masonry. For the first time physical and mechanical properties as well as frost resistance have been combined under the same research program. This research program was triggered and managed by practitioners to meet the need of major conservation projects carried out in Canada by the federal government.

This paper presents an overview of the testing program, its performance criteria, and its key results. With respect to preservation standards, this paper provides an overview of the application of testing standards to this research program for repointing mortars in laboratory conditions and in-situ. It highlights situations where standards had to betailored to the preservation needs or developed as new testing procedures.

The most important difficulties of this research program with respect to the development of preservation standards are as follows: 1) as the intent of modern masonry design is often different from traditional masonry, few existing standards are directly applicable; 2) there are no existing testing standards which specifically assess the durability of historic mortars; 3) some tests are too costly to be used in a testing program in practice; 4) excessive time is needed for some existing tests for quality control and site supervision.

Practice currently suffers considerably from the lack of appropriate standards for the testing of traditional masonry mortars. There is a great need for preservation standards and only limited resources to address the situation. A well orchestrated and major collective effort is required to adjust and develop testing standards for the preservation of our masonry heritage.
The Pyramid of Chephren, the Colosseum and the Temples of Angkor: Diagnosis and Safety Evaluation
Authors: Croci G , Viskovic A
Published: March 2009

Conservation, strengthening and restoration of Architectural Heritage require first of all a full understanding of the structural behaviour, of the materials characteristics and of the causes of decay and damage. Then safety levels can be evaluated and remedial measures decided.

Unfortunately these operations can't be based only on objective evaluations and mathematical analysis, due to the difficulties to have reliable data and to reduce the complexity of the reality and of the phenomena to semplified schemes; it is necessary, therefore, that those quantitative analysis would be associated with qualitative ones, based on the direct observation of the structural damage and materials decay, on the historical survey, etc., all of which makes very difficult to establish rules and codes in a traditional way: standards, guidelines, or recommendations, should trace out more a coherent methodology than mathematical rules.

An “explanatory report”, where all the different phases of the study are shown, may help to give scientific value to all the process.

In the paper are described three studies - the pyramid of Chephen in Egypt, the Colosseum in Rome and the temples of Angkor in Cambodia - to show how it would be difficult to understand their structural behaviour and to take appropriate decisions just following traditional mathematical methods; it is integrating these structural analyses with the qualitative information resulting from the historical research and the careful observation of the monument that a scientific approach can be laid down.
Comparison of Horizontal Load Transfer Curves for Laterally Loaded Piles from Strain Gages and Slope Inclinometer: A Case Study
Authors: Pinto PL , Anderson B , Townsend FC
Published: March 2009

Laterally loaded deep foundations are commonly analyzed using the Winkler model with the soil-pile interaction modeled through nonlinear springs in the form of p-y curves. Computer programs such as FloridaPier and COM624P use default p-y curves when performing lateral analyses. These curves are based on input soil properties such as subgrade modulus, friction angle, undrained shear strength, etc. Soil properties must be deduced by laboratory testing or correlation to in situ test results. This is a source of uncertainty. In a few cases, lateral load tests are performed on instrumented piles, and the validity of such assumptions can be assessed. Test piles are commonly instrumented with strain gages and/or inclinometers. P-y curves can be back computed from these data, and the curves obtained with the two methods should agree closely. Results from a field test on a concrete pile are presented and the critical factors for the analysis are discussed. One added difficulty with concrete is its nonlinear behavior particularly near structural failure. The curves obtained are also compared with those developed from the Dilatometer/Cone Pressuremeter Test and the Standard Penetration Test.
Instrumentation for Monitoring Large-Span Culverts
Authors: Webb MC , Selig ET , McGrath TJ
Published: March 2009

An extensive instrumentation plan was devised to monitor large-span culvert behavior, soil behavior and culvert-soil interaction during backfilling and during live load testing. The goals of the instrumentation plan were to help control construction deformations, including insuring safe working conditions, and to gather sufficient data to advance the state of the art in the design and construction of large-span culverts. The instrumentation plan and sample results are discussed.

A 9.1 m (30 ft) span reinforced concrete arch and a 9.5 m (31 ft) span structural plate corrugated steel arch large-span culvert were tested. Both had shallow cover and live loads. Two tests were conducted, one with dense backfill and one with loose backfill.

Measurements were made of culvert shape, culvert strains, culvert-soil interface pressures, soil density, soil stresses, soil strains, foundation movements, temperature, cracking of the concrete culvert and shear movements between precast concrete segments. The most unique measurement was made by a custom built laser device for measuring movements of specific points on the culvert wall. The accuracy of this device was verified by level survey and tape measurements.

The instrumentation performed well and measured results were within the range expected. Culvert deformations were efficiently measured without impeding construction operations. Culvert-soil interaction effects during backfilling and during live load testing were reasonably defined with the instruments selected.
Measurement of Earth Pressures on Concrete Box Culverts under Highway Embankments
Authors: Yang MZ , Drumm EC , Bennett RM , Mauldon M
Published: March 2009

To obtain a better understanding of the stresses acting on cast-in-place concrete box culverts, and to investigate the conditions which resulted in a culvert failure under about 12 meters of backfill, two sections of a new culvert were instrumented. The measured earth pressure distribution was found to depend upon the height of the embankment over the culvert. For low embankment heights (less than one-half the culvert width), the average measured vertical earth pressures, weighted by tributary length, were about 30% greater than the recommended AASHTO pressures. The measured lateral pressures were slightly greater than the AASHTO pressures. As the embankment height increased, the measured weighted average vertical stress exceeded the AASHTO pressures by about 20%. Lateral pressures which exceeded the vertical pressures were recorded at the bottom of the culvert walls, and small lateral pressures were recorded on the upper locations of the wall. The high lateral pressures at the base of the wall are consistent with the results from finite element analyses with high density (modulus) backfill material placed around the culvert.
Two Weight System for Measuring Depth and Sediment in Slurry-Supported Excavations
Authors: Deming P , Good D
Published: March 2009

This paper describes a two weight system using bar and flat shaped weights for measuring depth and detecting sediment at the bottom of slurry-supported excavations. Currently there are no standard depth measurement weights or methods for reliably identifying bottom sediment. Two weights and a procedural system for using the weights is described. Details suitable for manufacture are provided.
Monitoring Preload Performance
Authors: Russell JB , Lawrence CA , Paddock MW , Ross D
Published: March 2009

Reconstruction of State Highway 29 (STH 29) in north central Wisconsin was complicated by two separate deposits of compressible peat and organic silt within the highway right-of-way. The deposits ranged from about 3 to 11 meters in thickness over about 900 meters of the reconstruction alignment. Excavation and removal of the peat and organic silt was evaluated, but was determined to be cost prohibitive. Preloading was determined to be a cost effective and environmentally friendly solution, and was implemented at both deposits to induce the expected consolidation and long-term secondary compression of the final highway embankment and pavement sections. This paper presents the design, instrumentation, and rheological modeling procedures used to complete the project.
Remote Field Methods to Measure Frost Depth
Authors: Benson CH , Bosscher PJ
Published: March 2009

This paper reviews the three common methods used to remotely measure frost depth: (1) soil temperature measurements, (2) soil electrical resistivity measurements, and (3) soil dielectric constant measurements. Soil temperature measurements are often made using thermocouples or thermistors. Specially designed probes are used to measure frost depth based on electrical resistivity. Inferences based on dielectric constant are usually made using time domain reflectometry. Frost depths based on soil temperatures are made equally well using thermistors or thermocouples. However, frost depths inferred from soil temperature measurements can be erroneous if the freezing point is depressed (due to unsaturated conditions or the presence of salts) or if the temperature profile is essentially isothermal and near 0°C. More reliable measurements of frost depth are made using electrical resistivity or dielectric constant measurements because the electrical properties of soil are affected more by phase change of the pore water than temperature.
Using Geomatics in the Acquisition and Management of Field Data
Authors: Brokaw WS
Published: March 2009

The term Geomatics refers to the integration of geographic information systems (GIS) with global positioning satellite (GPS) technology, remote sensing and communication technology, (i.e., the Internet). A project involving the collection of environmental data at a site follows a series of consecutive events. The initial step is to identify project parameters and determine data needs. Data capture methods (i.e. collection and analyses) are selected and then implemented in the field. Once the data are generated, organization and communication are essential in making the data useful. The objective of using Geomatics is to facilitate the acquisition and management of data and to provide a mechanism for effectively communicating this information.

Before a field work is initiated, valuable information about the site and surrounding area can be obtained via the Internet. Homepages maintained by the US Geographic Survey, US Census Bureau and environmental organizations provide maps and other regional data in digital format, enabling a project manager to assess a wide range of regional conditions. Aerial and satellite photographs can be obtained to further understand the site and surrounding area. As site-specific data are generated, the geographic coordinates of each sampling point can be accurately and rapidly determined with GPS receivers. Using GIS software, a project manager can efficiently integrate the GPS geographic coordinate data with analytical data and the information obtained from the Internet-aerial photographs. GIS serves as the primary data management engine, organizing and providing access to all information generated as part of the project. The Internet can be utilized to disseminate the information to concerned parties.
Compaction Comparison Testing Using a Modified Impact Soil Tester and Nuclear Density Gauge
Authors: Erchul RA
Published: March 2009

The purpose of this paper is to compare test results of a modified Impact Soil Tester (IST) on compacted soil with data obtained from the same soil using a nuclear density gauge at the U.S. Army Corp of Engineer's Buena Vista Flood Wall project in Buena Vista, Virginia. The tests were run during construction of the earth flood wall during the summer of 1996. This comparison testing demonstrated the credibility of the procedure developed for the IST as a compaction testing device. The comparison data was obtained on a variety of soils ranging from silty sands to clays. The Flood Wall comparison compaction data for 90% Standard Proctor shows that the results of the IST as modified are consistent with the nuclear density gauge 89 percent of the time for all types of soil tested. However, if the soils are more cohesive then the results are consistent with the nuclear density gauge 97 percent of the time. In addition these comparison tests are in general agreement with comparison compaction testing using the same testing techniques and methods on compacted backfill in utility trenches conducted earlier for the Public Works Department, Chesterfield County, Virginia.
The Key Role of Monitoring in Controlling the Construction of the New Jubilee Line between Waterloo and Westminster, London
Authors: Osborne NH
Published: March 2009

Crucial to the success of Contract 102 of the Jubilee Line Extension Project (JLEP) was the detailed analysis of the impact of the construction process on the surrounding ground, structures and tunnels under construction. The construction works were to pass under or alongside some of London's most historic and prestigious buildings, consequently stringent limits were imposed upon ground and structure movements. To control these movements and remain within the limits set, a comprehensive monitoring system was required, comprising a wide variety of instruments linked to a geotechnical database. An extensive and integrated instrumentation system was designed to produce quality data and as no monitoring system existed that covered the unique requirements of the contract and of the Balfour Beatty Amec Joint Venture (BBA), the option was taken by BBA to design and develop a system in house.

The result was Geosys, a windows based monitoring system that could handle data from the various instruments on site, fulfilling a major role in the successful observational approach that was taken to control ground movement from both the tunnelling and the grouting. Geosys enabled electronic data to be reviewed in “real time” and the surveyed precise levelling results could be reviewed within half an hour of survey, if required; feedback loops into the design resulted in a major impact upon the construction decision making processes. The data handling and processing developed within Geosys are described. The subsequent geotechnical benefits to the contract, through the application of high quality processed monitoring data to the control of the ground movements and the construction works, are discussed.
Further Studies on T*ε Integral for Curved Crack Growth
Authors: Lam PW , Kobayashi AS , Atluri SN , Tan PW
Published: March 2009

T*ε integral values associated with stable, curved crack growth in biaxially loaded, fatigued precracked, 2024-T3 single edge notched (SEN) specimens were determined. The SEN specimens were loaded under combined Modes I and II and mimicked the flapping of a failed lap splice joint of a pressurized airplane fuselage. Most specimens were provided with a tear strap, which was either bonded, bonded and riveted, or integrally machined (machined pad-up) in the specimen. The stably growing crack curved and either penetrated or curved again upon hitting the tear strap. The displacement field, which was determined by Moiré interferometry as well as with finite element analysis, was used to directly determine the T*ε and T*2ε integral values. These T*ε values agreed reasonably well with those determined by an elastic-plastic finite element modeling of the experiments. T*1ε was identical to that obtained previously for pure Mode I crack extension while the T*2ε integral oscillated about its null value. The results of this study suggest that T*1ε could represent the resistance for locally selfsimilar crack growth and that a crack will curve in the direction of vanishing T*2ε.
Recommendations for the Determination of Valid Mode II Fracture Toughnesses KIIc
Authors: Hiese W , Kalthoff JF
Published: March 2009

From a discussion of the sizes of the plastic zones at the tip of a crack under shear (Mode II) and tensile (Mode I) conditions of loading, hypotheses on specimen size requirements are derived for determining valid values of the shear fracture toughness KIIc. The following conclusions are drawn: The minimum specimen thickness for a KIIc test can be smaller, but the minimum in-plane specimen dimensions should be larger than for a KIc test. For verification of these hypotheses, Mode II and additionally Mode I fracture toughnesses were determined for the aluminum alloy 7075 and the tool steel 90 MnCrV 8. Measurements were performed with specimens of different sizes with respect to the size of the crack tip plastic zones. The obtained data are in good agreement with the derived criteria for measuring Mode II fracture toughnesses KIIc and confirm their validity.
Micromechanical Modeling of Mixed-Mode Crack Growth in Ceramic Composites
Authors: Zhai J , Zhou M
Published: March 2009

Dynamic crack propagation in ceramic composites is analyzed numerically. The simulations concern the effects of microstructural morphologies on fracture. The analysis coniders arbitrary phase distributions in the actual microstructures of alumina/titanium diboride (Al2O3/TiB2) composites. The microstructures analyzed have different phase morphologies and different phase sizes over an order of magnitude in length (from 1–2 to 10–20 μm). A micromechanical model that provides explicit account for arbitrary microstructures and arbitrary fracture patterns is developed and used. The approach uses both a constitutive law for the bulk solid constituents and a constitutive law for fracture surfaces. The model is based on the cohesive surface formulation of Xu and Needleman and represents a phenomenological characterization for atomic forces on potential crack/microcrack surfaces. This framework of analysis does not require the use of any fracture criteria. Instead, fracture evolves as an outcome of bulk material response, interfacial behavior, and applied loading. This approach provides a unified and self-consistent treatment of mixed mode fracture. The evolutions of crack lengths in different phases and along interphase interfaces are calculated to track crack growth. The overall local crack speed, defined as the time rate of change of arc length along zigzagging crack paths, is found to reach the intersonic range, i.e., greater than the shear wave speeds and smaller than the longitudinal wave speeds in the constituent phases. The model also allows the energy release rate to be evaluated easily. For the same amount of crack surfaces generated, the average energy release rates for fracture patterns in four microstructures analyzed differ by up to 25%. The results demonstrate that larger TiB2 reinforcements significantly impede crack propagation and increase the fracture resistance of the composites, as indicated by higher average energy release rate values.
The Propagation of a Circumferential Fatigue Crack in Medium-Carbon Steel Bars Under Combined Torsional and Axial Loadings
Authors: Tanaka K , Akinawa Y , Yu H
Published: March 2009

The propagation behavior of a circumferential crack in a cylindrical bar of a medium carbon steel was studied extensively under various combinations of cyclic torsion and axial loading. First, the threshold condition of fatigue crack propagation was discussed in terms of the stress intensity factor. The threshold condition of fatigue crack extension was expressed by a quarter-elliptic function of the stress intensity ranges for Mode I and III. The equation can be derived on the basis of the crack-tip displacement criterion. The threshold condition for fracture is also expressed by another quarter-elliptic function. Next, the J-integral was applied to flat-type fatigue crack propagation with excessive plasticity under high cyclic loads. The crack propagation rate was expressed as a power function of the J-integral range for Mode I, and also for Mode III. The propagation rate is lower under Mode III loading than under Mode I loading, when a comparison is made at the same ΔJ value. The crack propagation rates under mixed-mode loading, as a function of ΔJ, lie between the relations for Mode I and Mode III. Striations were observed on the fatigue fracture surface that was created under mixed mode loading, and the striation spacing was equal to the crack propagation rate as it also was for the case of Mode I loading.
Near-Threshold Crack Growth Behavior of a Single Crystal Ni-Base Superalloy Subjected to Mixed-Mode Loading
Authors: John R , DeLuca D , Nicholas T , Porter J
Published: March 2009

Ni-base single crystal superalloys, which are used in applications such as gas turbine engine blades, are primarily loaded along the (001) direction. Mode II (crystallographic shear) type cracking along the (111) plane is frequently the mode of growth in the early stages of fatigue failure of these components. Disks with a middle crack were used to characterize crystallographic shear crack growth from machined flaws oriented parallel to a (111) plane of a single crystal alloy. Automated crack growth experiments were conducted at constant stress ratio in the near threshold regime. Various combinations of Mode I and Mode II loading were achieved by orienting the machined flaw at different angles (θ) to the loading axis. Loading angle θ = 0° (pure Mode I loading) resulted in crystallographic crack extension along alternating (111) slip systems producing a zig-zag pattern. This orientation exhibited significant resistance to self-similar crack growth from the machined flaw. In contrast, self-similar crack growth was achieved with relative ease for loading angles, θ ≠0° (mixed mode). In the mixed mode tests with KI > 0, the crack growth rate was 10 to 50 times higher than that under Mode I loading. Preliminary results indicate that crack growth is non-crystallographic at 593°C.
Net-Shaping of Co-Cr-Mo (F-75) via Metal Injection Molding
Authors: Tandon R
Published: March 2009

Metal injection molding (MIM) is a recognized processing route for net- and near-net-shape complex parts for use in medical, automotive, industrial, and consumer industries. The MIM process holds great potential for cost reduction of orthopaedic implant devices for applications such as femoral components, tibial bases, cable crimps, and tibial trays. This study discusses the effects of processing parameters on the liquid-phase sintering behavior of injection molded ASTM F-75. Tensile test specimens were molded, debound, and sintered using different atmospheres. The static mechanical properties of the sintered alloys were compared to the cast and cast/HIP ASTM F-75. The liquid-phase sintered/solution-annealed MIM F-75 exhibited yield and tensile strengths greater than 550 and 900 MPa, respectively, with an elongation bf 17%, thus exceeding the minimum requirements of the ASTM cast F-75. The HIP'ed and heat treated MIM specimens exhibited yield and tensile strengths of 500 and 1000 MPa, respectively, with an elongation of 40%. The sintering atmosphere played a major role in determining the static mechanical properties of the alloy, which can be partly attributed to the final carbon content. The maximum as-sintered density achievable was 8.2 g/cm3. Since porosity is detrimental to the fatigue resistance, the as-sintered specimens were containerless hot isostatically pressed to eliminate any residual porosity. Rectangular test specimens were also molded, from which samples were machined in accordance with the ASTM Standard Practice for Conducting Constant Amplitude Axial Fatigue Tests of Metallic Materials (E466) to determine the fatigue properties of smooth and notched specimens. The MIM specimens performed similarly to the cast F-75, indicating a viable application of the MIM technology for F-75 implants.
The Production and Properties of Wrought High Carbon Co-Cr-Mo Alloys
Authors: Berry G , Bolton JD , Brown JB , McQuaide S
Published: March 2009

The medical implant market's requirement for a forged version of the normally cast only, high carbon (approximately 0.2%) variant of the Co-Cr-Mo alloy, which would combine increased wear resistance with the mechanical properties of the low carbon (approximately 0.05%) variant of Co-Cr-Mo, initiated an investigation to establish a viable manufacturing route for the high carbon variant. Initially, a single melted (vacuum induction melted) cast and forged route, and a metal spraying process were examined. Subsequently a vacuum induction melted, electroslag remelted and hot working route was developed using a number of compositional and thermo mechanical processing variants. The mechanical properties obtained on rolled and forged high carbon Co-Cr-Mo bar from 20mm to 50mm diameter were similar to those of the low carbon variant and also met the requirement of ASTM F1537-94 (warm worked). The wear resistance of the high carbon variant, measured using a pin on disc method, indicated some advantage over the low carbon variant at high applied loads.