bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nondestructive Testing Techniques and Evaluation Procedures for Airfield Pavements
Authors: Alexander DR , Kohn SD , Grogan WP 
Published: December 2008

Research efforts at the Waterways Experiment Station have resulted in the development of a pavement evaluation methodology based upon a multilayered elastic model and limiting stress/strain criteria which use deflection basin measurements obtained by applying a load to the pavement surface with a nondestructive testing (NDT) device.
Growing acceptance of the NDT methodology has led to the formulation of a comprehensive nondestructive testing and evaluation procedure for airfield pavements which has been used by and is under consideration for adoption by the Army and is also being used by the Air Force and Navy (there is presently no official DA published manual or standard for NDT, but one is currently being drafted). A testing scheme is presented for airfield pavements that includes recommendations for the number of tests, location of tests, magnitude of NDT loadings, and sensor spacings. In addition to NDT data, other information such as layer thicknesses, surface and five-day mean air temperatures, and portland cement concrete flexural strengths are required for an accurate evaluation. The computer program BASIN has been developed to graphically and statistically analyze NDT deflection data and to select a representative deflection basin to be used for the evaluation of a pavement section. A description of the modulus backcalculation process using the computer program BISDEF is provided. The final evaluation is based upon a projection of the total number of passes of each aircraft type that a pavement will be expected to support over its design life. A method is described for determining the critical aircraft and design pass level for a given projected aircraft mixture. Allowable aircraft loads, strengthening overlay requirements, etc. are then obtained using the moduli from BISDEF and the program AIRPAVE, which compares stresses and strains within a layered system to appropriate limiting criteria. Limiting stress/strain criteria included in AIRPAVE have been calibrated with performance data to ensure consistency with current Corps of Engineers design criteria.
The use and significance of the pavement classification number (PCN) determined from the allowable load rating for expressing the load-carrying capacity of a pavement by a single unique number without specifying a particular aircraft is discussed. Sample data have been used to demonstrate evaluation techniques and the presentation of results.
The NDT procedure presented here provides a rapid and versatile method for determining the structural capacity of a pavement system. Rigid, flexible, and composite pavements consisting of stabilized or unstabilized layers can be evaluated by using data from a variety of commercially available NDT equipment. While developed to meet specific military requirements, the procedures are equally applicable to the evaluation of civil airports and could be modified to include the evaluation of roads and streets.
Twenty Years of Nondestructive Testing and Backcalculation of Moduli for Pavements in Argentina
Authors: Tosticarelli J , Poncino H , Angelone S , Giovanón O , Martínez F , Pagola M 
Published: December 2008

This paper deals with experience acquired in Argentina in nondestructive testing of pavements and back calculation of moduli from 1967 to 1987 by the research group of the IMAE (Institute of Applied Mechanics and Structures). National University of Rosario.
The paper addresses three fundamental areas of engineering research concerning nondestructive testing (NDT): 1. The in situ measurement of material strengths using various NDT devices. 2. The measurement of resilient modulus of soils and granular materials, and dynamic moduli of bound surface materials. 3. Back calculation of moduli using various analytical models on microcomputers.
In situ nondestructive testing measurements have included surface wave propagation methods, the Lacroix deflectograph, and a specially fabricated double Benkelman beam which allows the easy calculation of the deflection basin. These measurements have been made on many different types of cross-sections over numerous roadbed soils.
Nondestructive laboratory measurements to determine the material strengths have included: ultrasonic pulse, resonance method, resilient moduli by dynamic compression and triaxial test, and dynamic moduli by indirect tension testing.
Development efforts have focused on modifying and adapting the ALIZE III elastic-layered program developed by Laboratoire Central des Ponts et Chaussées (LCPC) in France for local conditions in Argentina.
Modifications have been made for the unique local soils, climate, and traffic patterns. The program has been adapted for use on handheld notebook microcomputers.
A Review and Evaluation of Instrumental Methods of Testing Phosphate Coatings
Authors: Kwiatkowski L , Kozlowski A 
Published: December 2008

A critical review of instrumental methods of testing phosphate coatings based on the literature and on experimental work was carried out taking into account their utility for research and for routine quality control. The possible methods found in the review account for the relatively small knowledge of the corrosion phenomena that occurs at the phosphated metal/electrolyte phase boundary. Potential drop during phosphating is an interesting method of recording the process, but no theoretical explanation of the curve is given. So far, applicability of the method is limited to porosity assessments in certain phosphating solutions and to some practical checks, that is, activators before treatment. The voltammetric method seems to be very doubtful from the theoretical point of view since constancy of the surface area and stability of the coating before and during measurements cannot be ensured, and the mechanisms of the electrode processes in pores and on the unphosphated substrate were not proved identical. It is assumed that the impedance method will find wider application provided the reliability of assessment of elements of the equivalent circuit and automatization of measurements and calculation are improved.
The less doubtful methods are microscopic and X-ray diffraction examinations, particularly determining phosphophyllite to hopeite ratio. However, some complimentary examinations explaining the effect of sample geometry and texture and the relation between the line intensity and unit mass are required. At present, this is probably the only standardizable instrumental method of testing phosphate coatings.
Methods for Monitoring Solvent Condition and Maximizing Its Utilization
Authors: Joshi SB , Donahue BA , Tarrer AR , Guin JA , Rahman MA , Brady BL 
Published: December 2008

This paper evaluates simple tests to be used as criteria for determining the condition of cold dipping (Stoddard solvent), vapor degreasing (chlorinated solvents), and precision cleaning solvents (Freon-113 and isopropanol), and for identifying when a solvent should be changed, thereby extending its usage life cycle. The use of these tests to monitor the quality of reclaimed solvent is also explored.
Several physico-chemical solvent properties were selected on the basis of sensitivity to solvent contamination, and the reliability and simplicity of the methodology for measuring these properties. Visible absorbance spectrometry was the most reliably measured property, followed by specific gravity, viscosity, and electrical conductivity. Additional testing is required for chlorinated solvents to determine inhibitor concentrations. These properties were monitored for several spent solvent batches and found to yield consistent results. The use of only one criterion based on one property would be adequate in most cases; however, the identification of when a solvent becomes spent can be determined more accurately when two or more criteria are used.
The major inhibitors present in trichloroethylene, tetrachloroethylene, and 1,1,1 -trichlo-roethane were identified using gas chromatography-mass spectrometry. These inhibitors can be classified as antioxidants, acid acceptors, and metal stabilizers. The inhibitor concentrations were monitored with usage time. Batch kinetic studies show that the reactions between the acid acceptors (butylene oxide, cyclohexene oxide, and epichlorohydrin) and hydrochloric acid, and between the metal stabilizers (1,4-dioxane and 1,3-dioxolane) and aluminum chloride were each second-order overall when tetrachloroethylene was used as a solvent. A simple test was also devised to determine the metal stabilizer concentration in a solvent.
Solvent reclamation by batch distillation is a viable option for significantly reducing solvent replacement and disposal costs. Batch distillation is most feasible when the same unit is used to reclaim multiple solvents. Simple physico-chemical tests, for example, absorbance, electrical conductivity, acid acceptance, and so forth, can be used to monitor the condition of reclaimed solvent, and to determine additive requirements. Reclamation studies on spent chlorinated solvents were carried out by using distillation and a carbon adsorption method.
Waste Oil Management for a Small Quantity Generator
Authors: DeFouw TH , Verdegan B , Zoch R 
Published: December 2008

Government regulations concerning “used oil,” underground storage tanks, and hazardous waste have a significant impact on industry. Many small business operations that were previously unregulated must reorganize their operations and develop hazardous material management plans that comply with the 1984 Resource Conservation and Recovery Act (RCRA) Amendments. Many of these facilities also have underground waste oil tanks to collect oil from several process areas. Waste oil that is determined to be a hazardous waste is costly to dispose of. A proper “used oil” management plan that prevents inadvertent contamination with hazardous wastes (that is, mixing with solvents, paint thinners) will lower the facility's disposal costs. This paper focuses on one small quantity generator's used oil management system that minimizes indiscriminate oil mixing and promotes oil reuse and recycling. This system could be installed and operated at any facility.
Ship bilgewater oil has been a problem in the maritime industry for a number of years. Extensive research has been completed on this problem and several solutions have been marketed. The same technology and equipment can be used in a manufacturing facility. A maritime oil/water separation unit was installed at a transportation service and repair facility as part of the tanker cleaning operation. The cleaning operation is as follows: steam and hot water are passed through a tanker to remove residual oils and vapors. The oil/water mixture is collected and processed through a treatment system to separate the oil and water.
Six field tests were made using different type oils and oil mixtures. The tests indicate that water discharged after processing contained less than 15-ppm oil and met discharge requirements for the local sanitary sewer system. The test results show the initial oil concentration before processing and the final discharge concentrations. The separated oil was collected by type into 208-L (55-gal) drums. Several drums of separated oil were reused for fuel in the facilities transportation and space heating equipment. The remaining oil was returned to the customer for reuse. By recycling the oil, the U.S. Environmental Protection Agency (EPA) does not consider the facility a waste generator. The recycled oil provides an additional fuel source thereby lowering the facilities operating costs. Oil collection in drums eliminates the need for an underground storage tank and compliance with tank regulations.
The system required less capital investment and installation than standard gravity separation systems (a cost comparison is presented in the paper). The equipment was located completely above ground and could be set up for fully automatic or manual operation. The equipment processes 0.5 m3/h (2.2 gpm), 1.75 m3/h (7.5 gpm), or 2.25 m3/h (10 gpm) of oily water.
The Use of Bitumen in the Stabilization of Mixed Wastes
Authors: Swindlehurst DP , Doyle RD , Mattus AJ 
Published: December 2008

Mixed wastes pose a problem to generators since there are no burial sites or treatment facilities currently accepting this type of waste. One potential disposal method is treating the waste to render it nonhazardous and disposing of it in accordance with radioactive waste requirements. A possible means of accomplishing this transformation is solidifying the waste in asphalt (bitumen).
Associated Technologies, Incorporated, in cooperation with Oak Ridge National Laboratory (ORNL), solidified in asphalt a surrogate sodium nitrate-based waste, spiked with extraction procedure (EP) toxic metals and nonradioactive cesium and strontium. This paper reports the characteristics of the spiked ORNL solution that was solidified as well as the properties of the solidified end product. The waste samples generated underwent EP toxicity testing as well as American Nuclear Society (ANS) 16.1 leach testing for 90 days, and the results of these tests are presented. Also, a discussion of the criteria for classifying a waste as hazardous is included in order to demonstrate that the waste, once solidified in asphalt, can no longer be considered hazardous.
Extraction Procedure Toxicity and Toxicity Characteristic Leaching Procedure Extractions of Industrial and Solidified Hazardous Waste
Authors: Shively WE , Crawford MA 
Published: December 2008

The 1984 amendments to the Resource Conservation and Recovery Act (RCRA) require that the Environmental Protection Agency (EPA) restrict the land disposal of certain hazardous wastes. The 7 Nov. 1986 RCRA amendments promulgated specific treatment standards and effective dates for the first phase of the land disposal restrictions (dioxin- and solvent-containing hazardous wastes). EPA also promulgated the Toxicity Characteristics Leaching Procedure (TCLP) for determining compliance for these wastes with applicable treatment standards.
The purpose of this study was to evaluate the performance of commercial hazardous waste treatment, storage, and disposal facilities (TSDFs). Five facilities were sampled representing a wide range of treatment processes. Sampling was performed to monitor all influent, effluent, and treatment residues associated with each process. Leaching evaluations of industrial waste treatment residues and solidified/stabilized wastes are presented in this paper. Extraction procedure (EP) toxicity tests for metals and toxicity characteristic leaching procedure (TCLP) analyses for metals, volatile organic compounds (VOCs), and semi-volatile organics are reported. The results demonstrate effective treatment resulting in nonhazardous residues in the majority of the cases. In several instances, the TCLP results for treatment residues are not within the recently promulgated regulations.
The waste composition and leachate results before and after treatment are compared. Metal hydroxide sludges from hydroxide precipitation processes were tested. A waste oil, a paint sludge, a biological treatment pond sludge, and a metal hydroxide plating sludge were tested before and after fly ash solidification. Plating wastes mixed with acids and neutralized with lime were tested after sulfide precipitation. Mixed plating sludges were tested before and after solidification with excess lime. Two ash residues produced by different solvent incinerators were tested. Compositional analyses showed varying quantities of organic compounds.
Comparative Studies of Metal Containment in Solidified Matrices by Scanning and Transmission Electron Microscopy
Authors: Neuwirth M , Mikula R , Hannak P 
Published: December 2008

Solidification/stabilization processes are widely used for the disposal of metal-containing industrial/hazardous wastes. There is little understanding of the mechanisms of metal containment in cementitious matrices. Leaching studies characterize the mechanism by which contaminants are released from the matrix, but give little information on contaminant-matrix interaction and the partitioning of contaminants within different phases of the solid structure. Recent studies have shown that different mechanisms are involved in stabilizing metals such as zinc and mercury [1,2] or cadmium and lead [3].
In this study, selected concentrations of metal salt solutions (cadmium, chromium, and lead) were stabilized using portland cement as additive. Scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and backscattered electron detection were performed on fractured and polished surfaces of specimens. Transmission electron microscopy (TEM) and X-ray microanalysis were carried out on ground particles of approximately 1 μm in size from the same specimens. The results indicate that different containment mechanisms are responsible for stabilization of the metals used and that they provide additional information on potential release of contaminants. The study shows the importance of correlating SEM and TEM analyses as well as other pertinent techniques in order to understand more fully the mechanism of waste containment.
The Use of Activated Charcoal and Tetra-Alkylammonium-Substituted Clays in Cement-Based Stabilization/Solidification of Phenols and Chlorinated Phenols
Authors: Sheriff TS , Sollars CJ , Montgomery D , Perry R 
Published: December 2008

A number of cement-based fixation processes are available for cost-effective stabilization of inorganic wastes, but these processes are not generally so effective for treating organic wastes or organic/inorganic mixtures. With a view to possible extension of such methods to organic wastes, the use of charcoal and tetra-alkylammonium-substituted clays as pre-stabilization adsorbents has been investigated. Charcoal is a well-known adsorbent, while the use of the substituted clays exploits the hydrophobic properties of the alkyl groups to fix organic materials within the clay matrix.
Wyoming Bentonite substituted with hexadecyltrimethyl ammonium bromide and benzyl-dimethyltetradecylammonium chloride were found to be very effective in adsorbing chlorinated phenols with adsorption capacities of 150 mg of chlorinated phenol per gram of clay. There appears to be a clear trend between the chain length of the alkylammonium ion in the exchanged clay and the ability of the clay to adsorb a particular phenolic compound. Activated charcoal was found to effectively adsorb 180 mg of phenol or chlorinated phenols per gram of charcoal.
The exchanged clays and charcoal together with the respective adsorbed phenols were incorporated into a number of cementitious matrices. Following hydration, leachability and physical strength measurements were carried out and the results were used to make a preliminary assessment of the longer-term potential of clays and charcoal in stabilization/solidification applications.
Influence of Hydrologic Factors on Leaching of Solidified Low-Level Waste Forms at an Arid-Site Field-Scale Lysimeter Facility
Authors: Jones TL , Skaggs RL 
Published: December 2008

The release of contaminants from solidified low-level waste forms is being studied in a field lysimeter facility at the Hanford Site in southeastern Washington State. The lysimeter facility, constructed in 1984, consists of ten 3-m-deep by 1.8-m-diameter steel caissons surrounding a 4-m-deep central instrument caisson. Each lysimeter contains one field-scale waste form (210-L barrel), obtained from a commercial power reactor. Solidification agents being tested include masonry cement, Portland III cement, Dow polymer, and bitumen.
Most of the precipitation at the Hanford Site arrives as winter snow; this contributes to a strong seasonal pattern in water storage and drainage observed in the lysimeters. This seasonal pattern in storage corresponds to an annual range in the volumetric soil water content of 11% in late winter to 7% in the late summer and early fall. Annual changes in drainage rates cause pore water velocities to vary by nearly two orders of magnitude, from approximately 4 cm/week in early spring to less than 0.01 cm/week in early fall.
Measurable quantities of tritium and cobalt-60 are being collected in lysimeter drainage water. Approximately 30% of the original tritium inventory has been leached from the only two waste forms containing tritium. Cobalt-60 is contained in all waste form samples and is consistently being leached from five lysimeters. Total cobalt-60 collected from each of the five lysimeters varies, but in each case is less than 0.1% of the original cobalt inventory of the waste sample.
Permeation of Solvent Mixtures Through Protective Clothing Elastomers
Authors: Ridge MC , Perkins JL 
Published: December 2008

Permeation through protective clothing is envisioned as a process involving solution of a chemical challenge into the elastomer and diffusion within the elastomer matrix.
The diffusion process is modeled using Fick's Laws, and steady-state permeation experiments are used to determine a proportionality constant, the permeation coefficient. This permeation coefficient includes both a solubility factor and a diffusion factor, and has been successfully used to characterize permeation rates.
In order to predict permeation resistance, researchers have focused on the solution step of the process. Models employing solubility parameters, such as Hildebrand's solubility parameter and Hansen's 3-dimensional solubility parameter have been employed with some success to predict both breakthrough time and permeation rate for specific elastomer-challenge combinations.
Mixtures of solvents are also characterized by solubility parameters, intermediate between the parameters of the individual components. Examination of limited mixture permeation data indicates that solubility parameter models can be extended to predict some aspects of permeation behavior.
Theory and work from other fields indicates that other aspects of permeation behavior, particularly those related to molecular kinetics may require alterations of the solubility parameter models. These aspects will be discussed.
Moisture Transport in Walls: Canadian Experience
Authors: White JH 
Published: December 2008

Canada Mortgage and Housing Corporation, the Canadian federal crown corporation responsible for federal housing policy, has been studying moisture problems in houses for several years. That study has usually been at the system level, that is, looking at the interaction between subsystems, components, and materials. It has spanned a wide range of regimes, from development of theory and a computer model, to laboratory tests on materials and walls, through test hut design and monitoring, to field surveys.
The published theory has been found wanting, in many cases. Designers, builders, inspectors, and material suppliers or manufacturers seem unaware of much that is known. More must be learned about the interactions that take place between energy, air, and moisture flows—over the full range of material moisture contents and air relative humidities and temperatures.
A systems model of the movement of heat energy, air, and moisture, in wood frame walls, is being developed and executed on a microcomputer. That program, named WALLDRY, will be made “user friendly,” then compared with field and laboratory data, but is primarily a research tool, and will likely remain too slow to be used as a regular design aid.