bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Laser Technique to Quantify the Size, Porosity, and Density of Clay Clusters During Sedimentation
Authors: Likos WJ , Lu N 
Published: February 2009

Abstract
A technique is developed for measuring the size, porosity, and density of clay clusters (flocs) and the distributions of these fundamental quantities during sedimentation. A laser-particle counter is used to detect cluster size and size distribution. Cluster velocities are computed by taking measurements at successive time intervals. By comparing the initial cluster size distribution with the measured distribution as sedimentation proceeds, a unique relationship between cluster size and settling velocity can be established. By applying a settling model for porous spheres, a unique relationship between cluster diameter and porosity is then established. Cluster density is calculated using fundamental mass-volume relationships. The technique and its working principles are illustrated via two sets of experiments, one for kaolinite clusters in distilled water and another for kaolinite clusters in 0.5 M NaCl. Consistent with double-layer theory, the results show that the porosity of clusters in distilled water is higher than the porosity of clusters in NaCl solution. The results also show that power-law relationships, which state that cluster porosity increases with cluster size, may not be valid for clusters very close to the primary particle size.
Development of a New In-Situ Direct Shear Test
Authors: Matsuoka H , Liu S , Sun D , Nishikata U 
Published: February 2009

Abstract
An in-situ direct shear test apparatus, in both small and large sizes, and its testing techniques have been developed. This test is performed simply by pulling horizontally a latticed shearing frame, embedded in the ground, with a flexible rope or chain under the application of a constant vertical load on the sample. In the new test, the real normal and shear stresses acting on the shear plane can be exactly measured. A number of the large-sized in-situ direct shear tests have been performed on eight kinds of coarse-grained granular materials including rockfills at different construction sites of embankments. The measured shear strengths approximate those of large-sized triaxial compression tests on samples with parallel grain-size distributions. The smaller version of this new test has been used successfully for testing sands and clays. For clays, artificially produced or in-situ, the measured undrained shear strengths are nearly equal to qu/2 by unconfined compression tests on the same clays. The extreme simplicity and high accuracy of this newly developed test are emphasized.
A Comparative Study of Particle Size Analyses by Sieve-Hydrometer and Laser Diffraction Methods
Authors: Wen B , Aydin A , Duzgoren-Aydin NS 
Published: February 2009

Abstract
Combined sieve-hydrometer method (SHM) is one of the two conventional methods commonly used in research and practice in all branches of science and engineering dealing with soils. SHM, however, has some inborn defects, which lead to systematical errors. The paper discusses the major causes of such errors in the analysis with examples from saprolitic soils derived from granites and volcanics. It is concluded that the deviations may be explained by three factors: differences in definitions and measurements of particle sizes; variations in densities of constituent grains; and turbulence in flow pattern of suspension. Particle size distribution (PSD) curves produced by the laser diffraction method (LDM) generally agree with those of SHM. However, some discrepancies between the results of these methods become evident upon closer inspection, and vary in extent according to the soil type and specific size fraction. For the same soil sample and a given fraction, such discrepancies can be mainly attributed to variations in density, shape, and mineralogy of particles. LDM with its many advantages over SHM should be adopted as the standard in geoengineering and geoenvironmental research, particularly involving problematic soils.
Steady State Strength of Sands in a Constant Volume Ring Shear Apparatus
Authors: Garga VK , Infante Sedano J-A 
Published: February 2009

Abstract
A modified volume ring shear test apparatus has been developed to undertake constant volume ring shear tests on sand. This constant volume test is a useful means of assessing the steady state strength of granular soils at large strain to determine the liquefaction potential of a soil mass. The apparatus and specimen preparation tools and methods are presented herein. The paper also presents the device and method used to verify the uniformity of the specimens prepared and the repeatability of the specimen preparation method. An experimental program has been conducted using both constant volume (CV) and constant load (CL) tests to investigate the effect of saturation, and of fines on the steady state line (SSL) and the steady state strength (SSS) envelope.
A Modified Soil-Geosynthetic Interactive Performance Test for Evaluating Deformation Behavior of GRS Structures
Authors: Ketchart K , Wu JTH 
Published: February 2009

Abstract
A modified Soil-Geosynthetic Interactive Performance (SGIP) test apparatus for evaluating short- and long-term deformation behavior of soil-geosynthetic composites was developed. In the test, a specimen of soil-geosynthetic composite, with dimensions of 305 mm wide, 605 mm long, and 305 mm high, was subjected to a vertical sustained load under plane strain condition. The applied load was transferred from the soil to the geosynthetic, and it allowed the soil and geosynthetic to deform in an interactive manner. Lateral and vertical displacements of the test specimen and strains in the reinforcement were measured. A series of the soil-geosynthetic performance tests were conducted to examine test repeatability, failure mode, and deformation behavior of different soil-geosynthetic composites. Test results and discussion of test results are presented. The applicability of the performance test to actual GRS structures was examined by comparing test results with measured behavior of a 5.4-m high GRS pier.
Electromagnetic Wave Propagation Model for Differentiation of Geotechnical Disturbances Along Buried Cables
Authors: Dowding CH , Summers JA , Taflove A , Kath WL 
Published: February 2009

Abstract
The lumped-circuit, hybrid, finite-difference/FFT (fast Fourier transform) model described herein simulates effects of multiple discontinuities in a coaxial cable at variable distances on a time domain reflectometry (TDR) signature. This model is verified by comparison with measured reflections from perfectly defined, multiple deformities. Accurate simulation is an important component of TDR technology as it allows improved calculation of the amount of shearing at multiple locations along special cables grouted in a rock or soil mass.
This paper is arranged in four sections. The introduction or background section presents the need for the model, nature of discontinuities, and the uses of long TDR cables. Design of the hybrid computer model is presented in the following section: Modeling of Coaxial Cable Response. Calculated and field-measured signatures are compared and methods of calibration are introduced in the section entitled: Calibration of Model and Comparison with Field Data. The paper closes with a summary and conclusions.
Variable-Head Field Permeability Tests in Driven Flush-Joint Casings: Physical and Numerical Modeling
Authors: Chapuis RP , Chenaf D 
Published: February 2009

Abstract
Two types of variable-head permeability tests in driven flush-joint casings, the end-of-casing test and the lateral injection test (Lefranc test), were performed in two sand tanks. Hydraulic conditions in the sand tanks included a constant vertical hydraulic gradient that was null, positive, or negative. The gradients were monitored by lateral piezometers, which confirmed that the large-scale hydraulic conductivity (k) value of the sand layer remained constant throughout the test program. Any interpretation method for these variable-head tests implicitly requires an assumed piezometric level (APL) for analysis. According to a common practice, the elevation of the ponded water surface above the sand deposit was taken as the APL to plot the test results as the logarithm of the difference in total head versus time. After each casing installation, permeability tests were performed for the three gradient conditions. When the vertical gradient was null in the tank, the test data provided straight lines as assumed in theory. When the gradient was positive or negative, the test data provided curved graphs that may be interpreted as giving k values that vary with time. The velocity graph method, however, provided the same constant k value for the three gradient conditions. It also detected the error in the APL and provided in all cases a local piezometric level (PL) equal to that given by lateral piezometer monitoring. Thus, the velocity graph method, a graphical representation of the conservation equation, eliminated the potential for misanalysis of variable-head tests. The experimental k values, as determined by the two types of tests, usually ranged between 0.5 and 2 times the larger-scale values determined independently by the monitored flow rates and gradients in the sand tanks. The variability in experimental k values was partly due to the local variations of void ratio and effective diameter of the sand, and partly due to the influence of casing installation. Numerical simulations of the tests confirmed the validity of the velocity graph method for providing k and the local piezometric level for a test.
Resonant Column Testing: The Inherent Counter EMF Effect
Authors: Wang Y-H , Cascante G , Santamarina JC 
Published: February 2009

Abstract
The standard magnet-coil driving system in resonant column devices provides the required cyclic excitation; however, it inherently produces a counter electromotive force that opposes the motion. In this study, the resonant column is modeled as an electro-mechanical system to quantitatively examine the counter electromotive effect and to explore its effect on resonant frequency and damping ratio computed from voltage-based measurements. The model is verified with two independent sets of experiments. Experimental and analytical results show that the measurement bias is more pronounced on the damping ratio than on the resonant frequency, the damping bias is not a device constant but varies with frequency, and the error is particularly relevant in low-loss and low-stiffness specimens (such as dry sands at low confinement). The electro-mechanical model permits developing device-specific correction charts that can be used to reexamine previously published damping ratio data gathered with voltage-based resonant column procedures.
Plane Strain Strength and Deformation of Sands Affected by Batch Variations and Different Apparatus Types
Authors: Yasin SJM , Umetsu K , Tatsuoka F , Arthur JRF , Dunstan T 
Published: February 2009

Abstract
Differences in the strength and deformation characteristics in plane strain compression between different batches of two sand types were critically evaluated. Two types of plane strain apparatuses were used. Large differences were observed between different batches of each type of sand, yet virtually no differences were found in particle physical properties including gradation, specific gravity, minimum and maximum void ratios, particle shape, and crushability. For each type of sand, differences in the measured peak strength between two types of plane strain tests were very small when effects of several possible influencing factors were accounted for. The prepeak dilatancy characteristics were noticeably different between the two types of plane strain tests, but the reason(s) could not be identified. The trend of inherent strength anisotropy was found to be very similar for the two plane strain apparatuses, but did depend on the sand type.
Resilient and Permanent Characteristics of Reinforced Granular Materials by Repeated Load Triaxial Tests
Authors: Moghaddas-Nejad F , Small JC 
Published: February 2009

Abstract
Drained repeated load triaxial compression tests were conducted to investigate the resilient and permanent stress-strain behavior of two granular materials reinforced by a geogrid. In order to obtain more accurate measurement of recoverable deformation, an on-sample measuring method was utilized. Because devices for measuring the axial and lateral deformation are attached to the specimen, the confining pressure is provided by applying a vacuum within the specimen. The effect of a geogrid in reducing the permanent deformation of soils at various combinations of deviator and confining stress is investigated and discussed. The test results indicate that a geogrid can play a significant role in reduction of deformation of the triaxial specimen, and could, therefore, be expected to reduce deformations in the field. However, the results obtained for resilient deformations show that the geogrid does not have a considerable influence on the resilient modulus of the two types of soil (sand and fine gravel) that were tested.
Transmissivity of a Nonwoven Polypropylene Geotextile Under Suction
Authors: Stormont JC , Ray C , Matthew Evans T 
Published: February 2009

Abstract
A permeameter has been developed for measuring in-plane transmissivity of geotextiles under a nearly constant value of suction along its length. The permeameter is capable of imposing gradients in excess of 10% and normal pressure up to 240 kPa, and permits the monitoring of the suctions within the geotextile during testing. To demonstrate the capability of the permeameter, a series of transmissivity measurements were made on a nonwoven polypropylene geotextile subject to different suction heads, normal pressures, and gradients. Transmissivities were up to two orders of magnitude less than the saturated value depending the on the magnitude of the suction head and whether the geotextile was being wetted or dried (hysteresis). Transmissivity values were independent of the gradient for these measurements. Increasing the applied normal pressure decreased the transmissivity at all values of suction head.
An Optical Technique for Investigating Soil Displacement Patterns
Authors: Gill DR , Lehane BM 
Published: February 2009

Abstract
An optical, nonintrusive technique for measuring soil deformation in three-dimensional laboratory scale tests is described. The technique combines the use of a video camera capable of recording the movement of targets to a high resolution, and a transparent porous material possessing geotechnical properties similar to natural clay. The technique is demonstrated in a model test conducted to measure soil deformation patterns around penetrometers. The displacement measurements compare well with results from other published tests and indicate that the technique can provide better resolution than has been previously achieved in similar laboratory tests.
Glass Transition of Asphalts Under Pressure
Authors: Schweyer HE 
Published: February 2009

Abstract
A study was made of the glass transition phenomena on 28 different types of asphalts by means of a simple dilatometric procedure. The study was made over a range of pressures from 1 atm pressure up to approximately 2000 atm in some instances. A study of the pressure susceptibility of the asphalt glass transition temperature demonstrated that there is a linear relationship between the glass transition temperature and the pressure. The slope of this relationship was evaluated as the pressure sensitivity of the asphalt. Data are also presented on the viscosity of certain asphalts at temperatures of 10 to 60°C under 500 atm pressure. From plots of viscosity temperature data the viscosity at the glass transition temperature under 1 atm and 500 atm are compared. It was found for many of the asphalt studies that the viscosity at the glass transition was approximately 109 poises for estimates at both 1 and 500 atm absolute pressures.
High-Temperature Properties of a High-Purity Ferritic Stainless Steel
Authors: Kies FK , Schwartz CD 
Published: February 2009

Abstract
The resistance of Alloy XM-27 to a variety of high-temperature environments was investigated. The alloy was tested in cyclic and semicontinuous oxidation and sulfidizing environments, and the results were compared to conventional, heat resistant alloys. Elevated tensile and stress rupture properties and resistance to embrittlement at 482, 704, and 982°C (900, 1300, and 1800°F) were evaluated.
Soil-Stress Gage Design and Evaluation
Authors: Triandafilidis GE 
Published: February 2009

AbstractA state-of-the-art review of the various basic types of soil-stress gages available today (1973) is presented. The basic parameters that influence soil-stress measurements as well as the design and evaluation criteria of soil stress gage instrumentation for laboratory and field applications are discussed. Soil-stress gage performance is evaluated in terms of geometry, stiffness, pressure-sensitive and gross gage areas, unit weight, natural frequency, calibration, waterproofing, temperature sensitivity, signal-to-noise ratio, and placement characteristics.
Temperature Influence on Corrosion Fatigue Behavior of 5Ni-Cr-Mo-V Steel
Authors: Ryder JT , Gallagher JP 
Published: February 2009

Abstract
An investigation of the below KIscc corrosion fatigue crack propagation behavior of 5Ni-Cr-Mo-V steel in a 3½ percent NaCl environmental solution is conducted with particular emphasis on the influence of frequency and temperature. The behavior is described using a generalized equation which incorporates the influence of temperature, frequency, and stress intensity range. The generalized equation 1dadN∣C=dadN∣F{H(ΔK,f,T)} relates the corrosion fatigue crack growth rate, dadN∣C, to the baseline cycle-dependent fatigue crack growth rate, dadN∣F. The function H is an environmental enhancement multiple. The severity of the temperature influence on environmentally enhanced fatigue crack growth rates of steels in aqueous environments appears to be related to the inherent resistance of the material to environmental cracking.
Crack Initiation and Growth in Plane Strain, Fully Plastic Zircaloy®
Authors: Kass JN , Begley JA , Andrejasik H 
Published: February 2009

AbstractA fractographic study of crack extension in plane strain, fully plastic Zircaloy® was conducted. Three specimen geometries were studied: double-edge notched, compact tension, and center notched specimens. Slip line solutions for these geometries predict high, moderate, and no stress elevation, respectively, ahead of the crack tip. These differences might be expected to produce different modes of crack extension. However, crack tip blunting effects were found to overwhelm geometry induced differences. Blunting was found in all three geometries. Stretched zone width was found to be ∼J/σy, or about 0.01 in. (0.254 mm), regardless of geometry. Several variations of blunted crack tip shape were observed for all three specimen types. Two methods of crack extension were observed for all three geometries studied. In the first method ellipsoidal holes were found to nucleate and grow ahead of the main crack tip. Growth continued until the ligament between the main crack and the hole was less than the major axis length of the hole. The hole then joins the main crack by means of local strain instability. The second method consists of alternate sliding off in a zigzag fashion. JIC was measured and found to be equivalent for all three geometries.
Short-Time Creep of Columbium and Tantalum Alloys at 2600 to 3200°F
Authors: Perkins RA , Wright ES 
Published: February 2009

Abstract
Uncoated Ta-17W and C129Y alloys and coated Ta-10W, C103, and C129Y alloys have been evaluated for short-time creep behavior at 2600 to 3200°F. The time for creep strains of up to 2 percent has been measured and the results have been used to derive empirical equations that predict short-time creep life in this temperature range. The equations give estimates of the time-to-creep strains of up to 2 percent at stress levels that will produce the maximum strain in 60 min or less. Silicide-base coatings appear to add to the creep strength of coated Ta-10W but have little added effect on the strength of the columbium-base alloys. The creep behavior of coated metals can be analyzed by the same empirical methods as those used for uncoated substrates. The results show that commercially available silicide coatings protect the substrate from oxidation with creep strains of up to 2 percent on exposures of 1 to 1½ h in this temperature range.
Axial Alignment Fixtures for Tension Tests of Threaded Specimens
Authors: Jones MH , Bubsey RT , Succop G , Brown WF 
Published: February 2009

Abstract
A fixture of simple design is described that is capable of providing very low eccentricity of loading in tension tests of threaded specimens. This fixture is suitable for use with the Method for Screening Tests Using Sharply Notched Cylindrical Specimens proposed by ASTM Committee E-24 on Fracture Testing of Metals. A special ½-in.-diameter (12.7-mm-diameter) evaluation specimen and associated procedure is described which is useful for determining the maximum bending that might be encountered in routine use of the fixture. The results obtained using this technique show that the maximum bending stress can be reliably limited to less than five percent of the average axial stress for an axial stress equal to or greater than 30 ksi (207 MPa) on the evaluation specimen. This evaluation technique is also suitable for verification of the satisfactory performance of other types of fixtures intended for use in the tension testing of sharply notched cylindrical specimens.
Decreasing the Fatigue Strength Reduction Factor by Dimpling
Authors: Shewchuk J 
Published: February 2009

AbstractA new approach to decreasing the fatigue strength reduction factor of holes in ductile sheet metallic material is presented. The material is first stretched by dimpling centering about the region where the hole is to be made. Subsequent flattening of the material creates residual compressive stresses in the dimple region. The hole is then drilled leaving the peripheral material in a state of compressive stress.Zero-to-tension fatigue tests on nominally 0.050-in. (1.27-mm) thick 2024-T3 alclad aluminum alloy specimens show a 36 percent decrease in the fatigue strength reduction factor by dimpling for 106 cycles to failure.
Signal Processing in Nondestructive Testing
Authors: Kennedy JC , Woodmansee WE 
Published: February 2009

Abstract
Signal averaging has been used to improve the clarity of flaw indications in an electron beam weld. The delay of an electronic gate has been synchronized to the transducer motion to improve the detectability of a tight interface crack in a tensile specimen. Cross-correlation techniques and multiple transducer arrays have been used to improve the signal-to-noise ratio of artificial flaws in welded panels. Signal averaging has been used to reduce random noise in the through-transmission ultrasonic inspection of a honeycomb composite. Megacycle range ultrasonic flaw information has been recorded on a low frequency FM tape recorder by rapidly sweeping an electronic gate through the time interval of interest. A lock-in amplifier has been used to produce quantitative data in both single-coil and double-coil eddy current systems. Cross-correlation techniques and a multiple-coil eddy current probe have been used to reduce surface roughness noise in an eddy current crack detection system.