bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Affecting Spontaneous Dispersion of soil Materials as Evidenced by the Crumb Test
Authors: Holmgren GGS , Flanagan CP 
Published: March 2009

Sixty-three soils were examined for spontaneous dispersion by various modifications of the crumb test. This test is considered indicative of dispersive conditions if a colloidal cloud develops when a small soil specimen is immersed in a large volume of water. Soil specimens were examined by this test in the dry state and in a remolded, saturated condition (slightly above the liquid limit). These pieces were immersed in distilled water and in 1 milliequivalent/litre (0.001 N) sodium hydroxide. The results of these tests were compared with the pinhole test as a reference measure of dispersion.
The use of saturated, remolded soil specimens resulted in a more conservative test for dispersion. More dispersive soils were identified properly, but more nondispersive soils were classified incorrectly as dispersive.
The 63 soils were separated further into four classes, depending on the agreement or disagreement of the saturated crumb test with the pinhole test. Chemical, mineralogical, and engineering data were assembled to assist in the search for explanatory variables affecting the discrepancies.
A second series of minicrumb tests was conducted using small remolded aggregates at various moisture contents and immersing them in an array of solutions of various pH and salinity. These arrays were photographed after 2 h to illustrate the effect of these variables on spontaneous dispersion.
The data developed from these several studies were used to illustrate the effects of sodium, salinity, pH, mineralogy, and initial moisture content upon the spontaneous dispersion of soil materials.
Erosion of Unsaturated Clay in a Pinhole Test
Authors: Lewis DA , Schmidt NO 
Published: March 2009

An investigation was conducted to determine the influence of dry density and initial water content on the erosion of a compacted dispersive clay. The pinhole test developed by James Sherard and associates was used to model the erosion conditions which occur in earth dams. When the soil specimens, compacted to densities representative of standard and modified Proctor effort were eroded under a roughly constant erosional shear stress, it was found that a minimum amount of erosion occurred at a water content about 2 to 3 percent wet of optimum water content. It was also found that, at the same water content, the amount of erosion tended to decrease with an increase in the dry density. However, neither water content nor density strongly controlled the dispersiveness of the soil. A mechanism of erosion was suggested to account for the observed reactions.
Also, it was found that the turbidity of the eroding water can be correlated with the concentration of suspended soil.
The Role of Dispersion in the Slaking of Intact Clay
Authors: Moriwaki Y , Mitchell JK 
Published: March 2009

A series of slaking tests was conducted to identify those conditions under which dispersion is the dominant mechanism of clay slaking. Variables investigated were clay mineralogy, adsorbed cation ratios (sodium/calcium), consolidation fluid electrolyte concentration, water content, and slaking fluid electrolyte concentration.
All clays with sodium ions occupying more than 10 percent of the exchange complex exhibited a dispersion slaking regardless of other conditions, provided the electrolyte concentration of the slaking fluid was lower than 10−3 N.
Observed slaking behavior can be classified into four modes: (a) swelling slaking, (b) dispersion slaking, (c) surface slaking, and (d) body slaking.
Case Histories of Repairs and Designs for Dams Built with Dispersive Clay
Authors: Phillips JT 
Published: March 2009

A sample survey of small earth dams in southern Australia showed that approximately 10 percent fail by a physical breach, usually associated with dispersive clays. Where information is available, it has been found that other factors combine to induce the failure. Typical failures are described.
Failures of engineer-designed and supervised dams are rare, but two such failures are described. The analysis of the failures, the repairs to the erosion tunnels, and other treatment to prevent further damage are presented. When first refilled, one dam again failed by an erosion tunnel adjacent to the repair section. Further studies led to this dam being completely demolished and rebuilt, using newly developed details for the reconstruction. These details were developed further for a similar new dam, and other details were used for the raising of another small dam.
The experience gained in the earlier cases led to the development of design details and construction techniques for the dispersive clay core of a 48-m-high earth-rockfill dam, and these are described.
Relevance of Atterberg Limits in Evaluating Piping and Breaching Potential
Authors: Reséndiz D 
Published: March 2009

In the last ten years, several researchers have contended that methods in use in soil mechanics do not permit identification of so-called dispersive clays, which are highly susceptible to piping and breaching. They also claim that current design criteria are unreliable for preventing piping and breaching in dam embankments and foundations.
On the basis of available information, the paper reanalyzes whether or not Atterberg limits as used in soil mechanics provide a means to predict piping and breaching potential. To that end, a critical review is made of relevant theoretical knowledge and empirical information regarding the effects of soil properties, compaction, and environment conditions on soil susceptibility to dispersion and erosion.
It is concluded that Skempton's activity, an index derived directly from Atterberg limits, is an excellent indicator of the piping and breaching potential of soils, though compaction water content and salinity of the percolating water should be accounted for as well. The implications of this conclusion on design criteria for water-retaining structures is also discussed.
Turbidity and Zeta Potential Measurements of Clay Dispersibility
Authors: Yong RN , Sethi AJ 
Published: March 2009

The basic mechanisms identified with dispersive clays have been associated with swelling or repulsive forces. To evaluate clay dispersibility from the particle interaction point of view, suspensions of the soil material can be used where resultant turbidity of the suspension is assessed. In this study, the light transmittance technique for measurement of turbidity is used whereby appropriate calculation techniques can be applied to the measurements to obtain equilibrium clay concentration remaining in suspension in the supernatant.
The adsorption/desorption measurements of the suspensions at various low salt concentrations indicate that desorption of the adsorbed ions from the clay surfaces contributes to clay dispersibility through increases in the double-layer thickness. The presence of amorphous silica and sesquioxides, as might be obtained from selective dissolution in the leaching process, reduces clay dispersibility, as indicated by increased zeta potential and refiltration rates.
Overview—Radiographic Nondestructive Testing Standards
Authors: Aman JK 
Published: March 2009

This paper is an overview of the standards in the field of nondestructive testing (NDT) radiography. The objective is to lay the overall framework and direction for more detailed coverage to follow. First, the NDT radiographic system variables are discussed in an effort to point out the need for increased standards activity. This activity should produce better precision in radiographic testing.
A framework of achieving the requisite precision at minimum cost is presented. This framework interrelates radiographic personnel, procedure, equipment and supplies, producing repeatable radiographs. The framework calls for controlling the system, which requires image quality indicators (IQIs) and adequate assurance as to requisite permanence of the radiograph.
The present status and future needs in standardization in each of the areas mentioned is covered. This includes a table of the standards and present activity on each of them.
NDT radiography is a flexible tool. The paper concludes with the challenge of building a more precise radiographic structure.
Classification of Industrial X-Ray Film
Authors: Polansky D 
Published: March 2009

A review of the efforts of a task group of American Society for Testing and Materials (ASTM) Committee E-7 on Nondestructive Testing to classify industrial X-ray film will be presented. The introduction of new film and especially automatic X-ray film processors with their relatively high temperature chemistry have changed considerably the sensitometric curves of film relative to that produced at normal temperature with hand processing. The objective of the task group is to classify film in order to indicate potential film performance and differentiate between the films.
The several methods of classification based on speed, speed and gradient, and mass of silver on a film will be discussed. The difficulties of specifying a system that may be too narrow or too broad will be discussed. The equating of film characteristics to the subjectively determined evaluation of radiographic film quality has not been accomplished satisfactorily. Systematic exposures of a standardized test plate have been made at several facilities and will be interpreted by several observers. The analysis of these data may help in equating film characteristics to radiographic film quality and, therefore, be the basis for a film classification system.
A Method for Assessing Deposits of Aerially Applied Aqueous Pest Control Agents
Authors: Cunningham DJ , Schafer EW , Starr RI 
Published: March 2009

In field evaluations of a promising bird repellent (mesurol) on target crops, we needed a method to measure the chemical deposits resulting from aerial spray applications. Oil-sensitive “spray” cards were unsuitable because water, not oil, was the carrier.
For spray cards, we used thin-layer chromatographic plates and determined particle size and density of the spray droplets and the resulting deposits of the chemical.
Equipment and Methods Available for Measuring the Behavioral Response of Rodents to Odors
Authors: Salmon TP , Marsh RE 
Published: March 2009

Odor attractants or repellents for modifying the behavior of rodent species have received considerable evaluation, but no single apparatus or method has evolved as the most effective. Some of the most useful types of equipment and procedures for olfactory-behavioral studies are described or discussed. Emphasis is placed on the equipment and methods most likely to prove effective and practical for evaluating odor attractants with a potential for use with traps or rodent baits.
Examples of devices used to monitor and record responses to introduced odors include electric eye, body capacitor, sensing grids, and mechanical treadles connected to counters and event recorders. Time-lapse photography and closed-circuit television monitors have their place, as does direct observation, but the labor involved makes them relatively expensive means of collecting data. A simple maze may be the most useful of all the apparatuses reviewed.
Chemosterilant Evaluation in Coyotes: Parameters for Animal Selection and Laboratory Methodology
Authors: Gates NL 
Published: March 2009

Investigations were conducted to establish criteria for selecting animals used in coyote chemosterilant research. Conclusions based on results from this study indicate that pen-raised pregnant female coyotes are preferable to wild coyotes for evaluating chemicals for abortifacient properties. Dogs were more practical than coyotes for preliminary out-of-season testing of antispermatogenic agents. Wild or pen-raised coyotes were suitable for use when necrotizing agents were used.
Selected standard hematologic and blood chemistry determination techniques were applicable for the purpose of monitoring systemic side effects of chemosterilant compounds.
Efficacy determination methodology was reviewed for practicality and accuracy. Unilateral testicular ablation was more suitable than biopsy techniques for collection of testicular tissue for histological examination.
A Metallurgical Examination of Control-Cooled, Carbon-Steel Rails with Service-Developed Defects
Authors: Sonon DE , Pellegrino JV , Wandrisco JM 
Published: March 2009

A metallurgical analysis was made of 33 carbon-steel rail samples selected from service, 31 of which had service-developed defects. The program was formulated to attempt to establish the metallurgical characteristics that promoted the defects and to establish possible interrelationships among these characteristics, the in-location service stresses, and the defects. This paper describes the results of chemical analyses, hardness and tension tests, and the results of wear, deformation, metallographic, and fractographic analyses. A companion paper in this symposium describes the results of Charpy V-notch impact toughness tests, fracture toughness tests, and fatigue tests.
The results of this investigation showed that (a) all the service-developed defects in the rail samples examined were fatigue cracks, (b) all these fatigue cracks initiated at sharp internal notches such as inclusions, and (c) a correlation between the metallurgical properties of the rail samples and defect formation could not be made.
Overall, it is reasonable to conclude that the service lives of the rails investigated would have been longer if the inclusions responsible for crack initiation had not been present. However, it should be noted that most of these rails had service lives lasting 16 years—454 million metric tons (MMT) (500 million gross tons (MGT)) with one sample lasting 22 years—685 MMT (755 MGT). Furthermore, the service stresses, although unknown, were apparently severe as evidenced in the deformation of the rail-heads.
It appears that of greater importance and interest with respect to the effect of steel quality and properties on defect formation in rails would be a study of defects that form early in the rail life. It is recommended that such studies be conducted.
Some Features and Metallurgical Considerations of Surface Defects In Rail Due to Contact Fatigue
Authors: Masumoto H , Sugino K , Nisida S , Kurihara R , Matsuyama S 
Published: March 2009

Two unique types of surface defects resulting from contact fatigue have been observed in rail used in high-speed lines in Japan (speed greater than 150 km/h). One of these results from the dark spots which randomly appear on the running surface and develop into transverse defects, and the other is the head check which arises at the gage corner.
An experimental simulation of these defects was attempted through rolling contact fatigue tests. The resulting defects were similar to those found on the running surface. For their initiation, a slip component of load was necessary, in addition to the normal load. Examinations of these defects indicated that they initiated on the contact surface, as did those found in rail, and not at the subsurface where the shear stresses are maximum due to Hertzian contact.
To investigate the effects of microstructure on the initiation and propagation behavior of these defects, coarse pearlitic, fine pearlitic, and tempered martensitic structures were examined. The fatigue limit of each structure showed a good correlation with its tensile strength. In the rolling contact fatigue tests, the fine pearlitic structure exhibited the longest lifetime. However, the tempered martensite had the lowest crack growth rate. Therefore, it is concluded that, to optimize the durability of rail steels, the effect of microstructure should be considered in addition to the tensile properties.
Microstructural Aspects of Fracture Toughness
Authors: Weiss V , Kasai Y , Sieradzki K 
Published: March 2009

For most technical materials the dominant mechanism resisting crack extension is plastic deformation. Continuum mechanics analysis shows that fracture toughness, in addition to depending on Young's modulus, flow stress, strain hardening exponent, and yield strain, should be nearly proportional to the effective fracture ductility obtained for the stress state characteristic for the region ahead of the crack; plane stress or plane strain. The original equation for plane-strain fracture toughness-equibiaxial ductility is refined to include the effects of strain hardening. Such a correlation has been experimentally confirmed for steels; KIc was found to be proportional to the effective equibiaxial ductility. A model for the thickness effect on Kc has been developed on the basis of these observations and is in fair agreement with experimental results.
The dominant microstructural events that control ductility, and therefore fracture toughness, are void nucleation, void growth, and void coalescence. Void nucleation at an inclusion—matrix interface is governed by the value of the interface strength—flow stress difference and is, consequently, temperature sensitive. Models for void growth mechanisms show the void coalesence strain to be a strong function of the nuclei density but rather insensitive to temperature. Qualitative relationships are presented which give some insight into the microstructural causes for ductility and fracture toughness transitions (or their absence in face-centered-cubic materials) with temperature, and can serve for the development of new high-toughness materials.
Rapid Assessment of Water Quality Using the Fingernail Clam, Musculium transversum
Authors: Paparo AA , Sparks RE 
Published: March 2009

An apparatus for testing the effects of drugs on the ciliary beating rate of clam gills has been modified to rapidly (15 min to 1 h) assess the effects of water quality factors on a sensitive organism, the fingernail clam, Musculium transversum. The gill and adductor muscles of the clam are excised and placed in a petri dish through which a continuous flow of molluscan Ringers solution or a test solution can be maintained. Normal ciliary activity of the gill preparation can be maintained for at least eight days. The ciliary beating rate is determined by synchronizing the rate of flashing of the substage lamp of a microscope, with the rate of beating of the cilia. Synchronization is achieved when the metachronal ciliary wave appears to stand still.
The first water quality factor selected for testing by the rapid method was potassium, because potassium concentrations are higher in the Illinois River where fingernail clams have largely died out, than in the Mississippi River where the clams are still abundant. The apparatus provided statistically reliable results in a short period of time. There are significant differences in the responses of large (7 to 11 mm) and small (1 to 5 mm) clams to: (a) removal and subsequent addition of potassium, (b) variation of maintenance dosage of potassium in the washing solution, and (c) lag period of response to a specific dose. The results suggest that an intracellular trans-membrane potential change (surface effect) is necessary to activate ciliated cells of small clams. This latter change in small clams would account for the relatively short lag period for potassium activation. Potassium levels required for maintenance of a basal ciliary beating rate are 10−3 M (39.1 mg/litre) for small clams and 10−6 M (0.039 mg/litre) for large clams. Greater concentrations are cilioinhibitory. Lesser concentrations are generally cilioexcitatory, but concentrations less than 10−3 M (0.00039 mg/litre) and 10−9 M (0.000039 mg/litre) are insufficient to sustain basal rates in large and small clams, respectively.
Potassium concentrations in certain rivers, such as the Illinois and Mississippi, are high enough to cause cilioinhibition in gill preparations from large fingernail clams. Inhibition of ciliary activity in intact clams would impair feeding and respiration.
The effects of potassium on the survival, growth, and reproduction of intact fingernail clams are currently being determined and will be related to the effects observed by means of the rapid method.
Time as a Factor in Biomonitoring Estuarine Systems with Reference to Benthic Macrophytes and Epibenthic Fishes and Invertebrates
Authors: Livingston RJ 
Published: March 2009

Estuarine and coastal populations undergo regular short- and long-term fluctuations in various functions which approximate diurnal, tidal, seasonal, and annual periodicities. This, together with a highly unstable physical environment, leads to considerable variation in temporal relationships of estuarine communities thus complicating biological monitoring programs. The implications of temporal variation of the natural environment are discussed relative to the biological sampling necessary to account for such variability; examples are taken from studies in three bay systems along the Gulf coast of north Florida.
The natural physicochemical functions in coastal systems are associated with rapid (diurnal) as well as long-term (seasonal) variations which should be determined from carefully designed sampling programs if causative elements of the impact of pollutants are to be determined. Against this background, the timing of pollutant entry into the system could control the actual nature of the impact. This should be related to natural cycles of various organisms in a given system after adequate determination of the timed sequence of biological variation. Regular changes of assemblages of epibenthic organisms, though often temporally stable on an annual basis, are only roughly synchronized with seasonal patterns of key physical functions such as temperature and salinity. Community structure can be masked or distorted by inadequate sampling either on a short-term or seasonal basis. This, together with seasonally directed changes in the actual impact of a given pollutant, should be taken into consideration in the design of a given biomonitoring program. The goals of each project should be reconciled with the short- and long-term variations of the biological system in question.
Results of a Round Robin Test Program on Hardness Conversion of Ferritic Stainless Steels
Authors: Heberling TG 
Published: March 2009

A round robin program was conducted to determine the hardness conversions for ferritic stainless steels. Each of six participating laboratories conducted hardness tests on specimens representing nine grades, each having varying amounts of cold reduction. Conversions were established to the Rockwell B scale from Rockwell 15T, 30T, 45T, and A scales.
In all cases, the Wilson Chart (Chart No. 52—Wilson Instruments Division, American Chain and Cable Company) conversion fits the least squares round robin data line better than does the ASTM Method E140 austenitic conversion. The Wilson Chart conversion line falls within the 95 percent confidence band of the round robin data for the conversions to Rockwell B from Rockwell 30T, 45T, and A. For the 15T to Rockwell B conversion, the Wilson line falls outside the 95 percent confidence limits for values below HRB 80.
As a result of this round robin program, a joint task group was organized under ASTM Subcommittees A-01.13 and E-28-06 to determine what changes should be made in the hardness conversion tables in ASTM Methods A 370 and E 140. The recommendations of this task group are currently being balloted.