bluuebunny/crossref_metadata_2025_split huggingface dataset:
Shear Strength of Degraded Reconsitituted Municipal Solid Waste
Authors: Harris JM , Shafer AL , DeGroff W , Hater GR , Gabr M , Barlaz MA 
Published: March 2009

Abstract
Relative changes in Waste shear strength parameters as a function of strain level and stress path are investigated based on the results of 16 direct simple shear (DSS) tests, one direct shear (DS) test with four stages, and three triaxial tests. The magnitudes of shear strength parameters obtained from drained DSS tests and undrained DSS tests with pore water pressure measurement were comparable. This was the case even though the effective stress path in both approaches was different. Data indicated the dependency of the mobilized strength parameters on strain, or deformation level. Generally, stress-deformation response increased monotonically with no well defined peak or ultimate stress levels. The results of the DSS and DS tests show no dependency of the strength parameters on the stress level. Results from DSS and DS indicated a range of effective strength parameters of 9 to 14 kPa for cohesion and 23°–29° for friction angle. Data from the triaxial testing showed dependency of the shear strength parameters on the initial compression stress level. Given the number of potentially confounding issues associated with the measurement of shear strength, it is rather important to also report information on sample collection methods, sample age and chemical composition, sample processing, sample composition, the size of testing equipment and level of strain (instead of ultimate or peak) at which the strength parameters are evaluated.
Development of TDR Penetrometer Through Theoretical and Laboratory Investigations: 1. Measurement of Soil Dielectric Permittivity
Authors: Lin CP , Tang SH , Chung CC 
Published: March 2009

Abstract
To better characterize a bulk soil electrically, both the electrical conductivity and dielectric permittivity should be measured. This study developed a time domain reflectometry (TDR) penetrometer to allow simultaneous measurements of dielectric permittivity and electrical conductivity during cone penetration. A TDR penetrometer is formed by placing a multiple-conductor waveguide around a nonconducting shaft. Probe design considerations and calibration methods for measuring dielectric constant were first theoretically discussed and then evaluated through laboratory investigations. A prototype TDR penetrometer was fabricated and used to perform simulated penetration tests in a calibration chamber. The effect of penetration disturbance on dielectric constant is quantitatively reported and explained. The implications of the data that can be measured by the TDR penetrometer are also discussed.
The Filter Paper Method Revisited
Authors: Marinho FAM , Oliveira OM 
Published: March 2009

Abstract
The calibration curve for any device or method to infer suction is the most important characteristic to evaluate for reliable measurement to be obtained. Some published literature (e.g. Houston et al. 1994; Bulut et al. 2001; Leong et al. 2002) have presented results in which the calibration for the filter paper method is not unique in relation to the type of suction (i.e., total or matric). A review of the data from the literature is presented, together with data showing the reason that justifies a unique calibration curve for the filter paper. It is also shown that it is necessary to check the calibration curve by performing a quick calibration check. A procedure for calibrating the filter paper for this check is given. Fundamental matters necessary for understanding the concept on which the filter paper method is based are also presented.
Selection and Use of Engine Coolants and Cooling System Chemicals
Authors: Committee D-15  
Published: March 2009

Description
The purpose of this publication is to provide practical information and advice on engine coolants as well as cooling system chemicals, such as cleaning compounds, antirusts, and stop-leaks. The references to cooling system services are confined to the practices directly affecting coolants, since the subject of general cooling system maintenance is already covered in published automotive literature.
Some Aspects of Quantitative Surface Analysis by Electron Spectroscopy for Chemical Analysis
Authors: Phillips LV , Salvati L , Carter WJ , Hercules DM 
Published: March 2009

Application of surface-sensitive spectroscopic techniques to quantitative surface analysis requires consideration of the distribution of species on the surface, as well as the characteristics of the technique. For electron spectroscopy for chemical analysis (ESCA), these problems are considered for the following situations: material adsorbed on a surface at less than monolayer coverage, a thin film of surface species overlaying the bulk, a sample distributed throughout the bulk in an inhomogeneous fashion, and a multilayered system.
Escape depth of photoelectrons becomes a particularly important parameter when comparing results of ESCA with those obtained by other techniques, such as Auger electron spectroscopy (AES). Different atomic ratios can be obtained from the same sample depending on the energies of electrons used.
ESCA can be used for trace analysis by preconcentrating metal ions on surface. The effectiveness of this technique depends on the equilibrium between the surface and solution. The form of the calibration curve obtained is influenced by “saturation” effects. The kinetics of the surface-solution equilibrium are also important.
Electron Spectroscopy for Chemical Analysis Examination of Rare Earth and Near Rare Earth Species
Authors: Barr TL 
Published: March 2009

A detailed electron spectroscopy for chemical analysis (ESCA) examination has been performed on a series of very pure rare earth foils, powders, and a sputter-deposited thin film consisting of yttria doped ceria. The foils were studied with their natural passivation layer intact and also sputter etched to provide approximate chemical profiles. The metals examined were cerium, lanthanum, and yttrium. The ESCA spectra of all of the passivated metals experienced charge shifts. Treatment of those shifts with an electron flood gun is an integral part of this study.
A semiquantitative analysis of the passivation layer of cerium establishes that the outer mantle is a mixed oxide-hydroxide Ce(IV) system, whereas the inner layers of the oxidative growth are initially mixed oxide-hydroxide Ce(III) systems and finally (close to the virgin metal) a substance believed to be Ce(III)2O3 is exposed. This is the first ESCA spectral analysis of the sesquioxide. Interestingly, sputter etching the ceric oxide/yttrium oxide (CeO2/Y2O3 film results in a nearly identical chemical development, indicating that some of these results may occur because of sputter reduction. The lanthanum and yttrium systems also display evidence of hydroxide formation on their outer (passivation) surfaces. A unique species which may be La(II)O is detected after sputtering into the passivation layer of lanthanum. The yttrium spectra for the CeO2/Y2O3 film exhibit superior resolution compared to that for the yttrium foil. A discussion of the satellite structure of these spectra is included.
Surface Analysis of Polymer and Glass
Authors: Sparrow GR , Mismash HE 
Published: March 2009

The unique physical nature of glass results in numerous surface phenomena which have long been unexplained due to difficulties experienced by analytical chemists undertaking their study. Modern, sophisticated surface analysis instrumentation now permits analysis of surfaces from the top monolayer into the bulk material.Detailed studies of glass surfaces provide the information necessary to understand how common cleaning, polishing, etching, and heat treatments affect the chemistry and properties of glass. Similar information obtained from studies of the first 30Å of treated polymers contributes to the understanding and explanation of their properties such as those related to oxidation, degradation, reflectance, hardness, and especially adhesion. The primary objective achieved through detailed surface analysis of the treated polymers was the knowledge necessary to develop better adhesion to polymers.Problems inherent in surface analysis of glass and polymers relate to their physical nature. Their surfaces are highly subject to ion migrations which are disconcerting to the analyst. The nonconductive or electrical insulating property defeats many instrumental methods of analysis. Combined high-performance ion scattering spectrometer (ISS), utilizing a recently developed cylindrical mirror analyzer (CMA), and a secondary ion mass spectrometer (SIMS) were used in these studies. The system was also equipped with a charge neutralization system and an automatic high-speed data processing device. Common soda lime glass was subjected to treatment by chromic acid, alcoholic potassium hydroxide (KOH), hydrogen fluoride (HF) vapor, and HF bath, and studied from the top monolayer to several hundred angstroms. Zirconium polished glass and various heat-treated glasses were studied similarly. Results were compared to analysis of the surface and bulk of untreated glass. A commercial polyimide, Kapton, cleaned by acid, base, solvents, and various drying techniques was surface analyzed. Surface information was correlated with original and residual contaminants and thin film bondability.Results indicated that most glasses are normally surface rich in sodium from 0 to about 30Å, but chemical cleaning by chromic acid, KOH, and HF vapor removes surface sodium, leaving a surface of primarily silica only. Heat treatment caused extensive concentration changes to several thousand Å. The surface carbon, nitrogen, and oxygen concentrations of a polyimide were substantially altered by simple cleaning treatments to about 30Å. However, the surface exhibiting greatest bondability of coated aluminum showed minimum contaminations due to metal such as sodium, magnesium, aluminum, silicon, potassium, calcium, and fluorine. The combined results illustrate that the extensive surface information available through modern analytical instrumentation contributes substantially toward understanding and controlling surface phenomenon not previously explained.
Effect of Specimen Width on Fracture Toughness of Ti-6A1-4V Plate
Authors: Hall GS , Seagle SR , Bomberger HB 
Published: March 2009

From a group of 96 specimens ranging in thickness from 15 to 38 mm (0.60 to 1.50 in.), a regression equation was obtained for Ti-6A1-4V plate relating the fracture toughness, KQ, of 205-mm (8-in.) wide specimens to the variables of specimen thickness and fracture toughness, KQ, for 76-mm (3-in.) width. The fracture toughness value of Ti-6A1-4V plate can be increased appreciably in thin specimens by using an oversized width specimen. The magnitude of this toughness increase diminishes as the thickness increases and approaches 38-mm (1.5-in.). Oversizing the specimen results in a significant reduction in the stress at instability at 2 percent crack extension. The specimen strength ratio, Rsc, essentially remains the same while Kmax and the Pmax/PQ ratio increase.
Crack-growth-resistance curves constructed from load versus crack-opening-displacement curves for the two different width specimens are similar. This indicates the fracture behavior is the same and not altered with increased specimen width. Furthermore, K values for oversized specimens can be calculated from the loads at the appropriate crack extension in smaller standard size specimens, and vice versa.
An Experimental Study of the Fracture Behavior of Laminated Graphite/Epoxy Composites
Authors: Brinson HF , Yeow YT 
Published: March 2009

The results of an experimental investigation on the fracture behavior of unidirectional and multidirectional laminated graphite/epoxy composites is reported. Critical tensile fracture stresses for constant head rate uniaxial specimens containing single-edge notches, double-edge notches, and centrally located circular holes are presented. Results are reported for loads and notches at various angles to the fiber direction(s). Evidence of notch sensitivity and stable crack growth is presented. Self-similar crack growth is shown to occur for only a limited set of circumstances.
Critical stresses are compared to the theories of Waddoups et al and Whitney et al. These comparisons are presented using isotropic and orthotropic stress concentration factors together with a finite width correction factor. The results tend to show that use of only isotropic correction factors allow good correlation between theory and experiment.
Evaluation of Selected High-Temperature Thermoplastic Polymers for Advanced Composite and Adhesive Applications
Authors: Maximovich MG 
Published: March 2009

Commercially available polyethersulfone (PES) and polyphenylquinoxaline (PPQ) resins were evaluated as high-temperature thermoplastics for advanced composite and adhesive applications. Continuous graphite reinforced laminates up to 400 plies thick were fabricated successfully from both systems, once processing parameters were defined. Structural as well as hemispherical shapes were postformed from consolidated flat laminates. Poor-quality panels were reprocessed to high-quality parts, using the thermoplasticity of the matrix resins.
The PES exhibited sensitivity to moisture as shown in the testing of both the neat resins and advanced composites. Adhesive bonds were also fabricated on 6A1-4V titanium adherends, using PPQ and thermoplastic processing techniques. The performance of the adhesive was improved significantly by the use of woven graphite scrim cloth. It is postulated that this scrim cloth results in significantly reduced residual stress in the bond line.
An Analysis Model for Spatially Oriented Fiber Composites
Authors: Rosen BW , Chatterjee SN , Kibler JJ 
Published: March 2009

This paper describes a material model for evaluation of the thermoelastic properties of fiber composite materials having a spatial distribution of fiber orientations. The approach is to construct a material model having a finite number of fiber orientations in a repeating unit cell. The basic material model is a minimechanical model based on the concept that a material system can be regarded as an assemblage of unit cells.
The unit cell models are constructed from impregnated yarn bundles and interstitial matrix regions. The predicted properties of these unit cells are those required for use in thermostructural analysis computer codes. The model treats anisotropic constituents, dispersed voids, temperature-dependent constituent properties, and fiber bundles oriented in many different directions.
Tensile and Compressive Behavior of Borsic/Aluminum
Authors: Herakovich CT , Davis JG , Viswanathan CN 
Published: March 2009

The results of an experimental investigation of the mechanical behavior of Borsic/aluminum are presented. Composite laminates were tested in tension and compression for monotonically increasing load and also for variable loading cycles in which the maximum load was increased in each successive cycle. It is shown that significant strain-hardening, and corresponding increase in yield stress, is exhibited by the metal matrix laminates. For matrix dominated laminates ([90], [±45]), the current yield stress is essentially identical to the previous maximum stress, and unloading is essentially linear with large permanent strains after unloading. For laminates with fiber dominated behavior ([0], [±30], [0/90], [0/±45]), the yield stress increases with increase in the previous maximum stress, but the increase in yield stress does not keep pace with the previous maximum stress. These fiber dominated laminates exhibit smaller nonlinear strains, reversed nonlinear behavior during unloading, and smaller permanent strains after unloading.
Compression results from sandwich beams and flat coupons are shown to differ considerably. Results from beam specimens tend to exhibit higher values for modulus, yield stress, and strength.
Moisture Effects in Epoxy Matrix Composites
Authors: Browning CE , Husman GE , Whitney JM 
Published: March 2009

The effect of absorbed moisture on the mechanical properties of a neat epoxy resin and derived graphite/epoxy composites is investigated. Glass transition temperature and modulus as a function of mositure content and temperature are determined for both the neat resin and composite. In addition, elastic modulus for the neat resin and strength and elastic moduli for unidirectional composites and quasiisotropic laminates are determined as a function of absorbed moisture and temperature. A method for predicting moisture content and through-the-thickness profile for a laminate exposed to a constant humidity and temperature is discussed. Particular attention is given also to the details of environmental testing.
Data indicate that absorbed moisture and temperature effects on the neat resin translate directly to matrix dominated properties of the composite and can lead to a change in failure mode, while filament dominated properties show very little environmental sensitivity. Results also indicate that resin glass transition temperature is a function of processing as well as absorbed moisture.
Dispersive Clay in Irrigation Dams in Thailand
Authors: Cole BA , Ratanasen C , Maiklad P , Liggins TB , Chirapuntu S 
Published: March 2009

Since 1970, a number of earth dams in northeast Thailand have suffered serious tunnel and surface erosion from rainfall, and several have failed during the first reservoir filling. The behavior is typical of dams containing dispersive clay. This paper describes the testing program undertaken to evaluate the embankment and foundation materials, and discusses the results. Laboratory testing included chemical analysis of the saturation extract, the U.S. Soil Conservation Service dispersion test and X-ray diffraction. Some correlation was found between the test results and the extent of the damage to various embankments.
In the search for nondispersive soil, the Emerson Crumb Test has been used for initial indications in the field, as well as being used, with modifications, in the laboratory.
A description is given of measures being adopted to repair two damaged dams with dispersive soil where nondispersive soil is not available. The repairs involve the replacement of eroded material and the prevention of any serious future damage to existing and new materials by physical and chemical treatments.
Laboratory Testing on High-Sodium Nondispersive Clays as Related to the Repair of a Clay Dam in Algeria
Authors: Francq J , Post G 
Published: March 2009

A 10-km-long homogeneous dam needed repair before filling as extensive cracking and slides occurred soon after completion. In order to design the repair, two sorts of clays were investigated: a gray plastic expansive clay constituting the old dam and a red sandy clay for the repair works. After Soil Conservation Service (SCS) tests and chemical analyses on the saturation extract, dispersiveness of the gray clay was feared, but pinhole tests proved it to be nondispersive. This allowed substantial savings on the design of the repair.
The red clay, after SCS tests and chemical analyses on the saturation extract, should not be dispersive. Pinhole tests gave dispersive reactions on air-dried specimens but nondispersive reactions on specimens at natural moisture content. Correlatively, the sodium content in the saturation extract decreases while calcium and magnesium content increases when air drying the red clay.
The conclusion may be that dispersiveness of a clay is more a result of the sodium that adheres to the clay particles than the sodium dissolved in the pore water.
Erosion, Corrective Maintenance, and Dispersive Clays
Authors: Ghuman OS , Allen RL , McNeill RL 
Published: March 2009

Erosion problems may result when the dispersive properties of clays are not suitably accounted for in the design of earth structures. These problems may become evident immediately upon introduction of water into the reservoir. An arid climate and alkaline soils are important indicators of the possible occurrence of dispersive clays. The phenomenon of dispersive clays has only recently been recognized, and all the effects are not yet understood.
Experiences in southern California projects are used to demonstrate how problems associated with dispersive clays may be identified. Test results leading to the recognition of such clays are outlined, and the different mechanisms of erosion are discussed. The choice between alternative corrective actions is dependent on a number of variables. These are identified, and a decision-making approach to the selection of appropriate corrective action is discussed.
A Rheological Approach to Dispersive Clays
Authors: Nickel SH 
Published: March 2009

The zone of expansion, formed on a wetted surface of a potentially dispersive clay, is modeled as a dilute clay slurry. This allows existing data from rheological studies of clay slurries to aid the understanding of the failure mechanism of dispersive clays.
Dispersive erosion is visualized as requiring three conditions: a passageway filled with flowing water, a zone of expansion on the wetted surface of the soil forming the walls of the passageway, and sufficient shear stress applied by the flowing water in the passageway to exceed the shear strength of the zone of expansion. Shear strength limits for dispersive, intermediate, and nondispersive soils are determined from an analysis of the pinhole dispersion test. The relative effects on the shear strength of the zone of expansion due to varying clay mineral type, predominant cation, slurry clay concentration, and electrolyte concentration are examined. Explanations are offered for anomalies in current chemical-empirical criteria for defining dispersiveness.
Dispersion in Some New Zealand Clays
Authors: Riley PB 
Published: March 2009

The dispersion of residual graywacke clays from near Wellington was investigated as part of the feasibility study for a water supply dam. The clay had a low salt content, but a high percentage of sodium. The clay was nondispersive and erosion resistant in the pinhole test.
A clay derived from weathering of tertiary rocks at a location near Auckland had similar salt contents, but was eroded in the pinhole test, indicating dispersivity.
Tunnel erosion also occurs on hillsides in the area in old landslips. However, this same clay has formed a waterfall in an adjacent stream for five years. This unusual behavior may possibly be explained by the stream having higher salt contents than the clay after floods, causing reverse diffusion of ions, and forming a protective skin on the clay.
Encountering Dispersive Clays on Soil Conservation Service Projects in Oklahoma
Authors: Ryker NL 
Published: March 2009

Dispersive clays occur frequently in nature, possessing properties detrimental to agronomic tillage practices and to engineering structures such as dams, terraces, channels, etc. Surface erosion occurs readily, since the fines are easily detached and suspended in runoff water. Where water can enter cracks in dispersive clays, subsurface erosion usually develops rapidly and extensively in areas of strong relief under favorable climatic conditions.
For many years, the Soil Conservation Service has relied upon the Laboratory Dispersion Test as the benchmark for identification of these problem clays. Improved sampling techniques and the supplementary use of two field identification tests have been extremely helpful in recent years, particularly in embankment zoning. Liming the surface layers of dispersed clay embankments has provided a satisfactory means for stabilization. Three lime-treatment jobs have not been damaged in seven years. Aluminum sulfate is being evaluated on a field trial basis.