bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calibration of Five-Segment Time Domain Reflectometry Probes for Water Content Measurement in High Density Materials
Authors: Wright WC , Yoder RE , Rainwater NR , Drumm EC 
Published: February 2009

Abstract
Time domain reflectometry (TDR) systems are being used widely for in situ measurement of soil water content. Water content is calculated based on the measured dielectric properties of the soil system. TDR systems for water content measurement were originally developed for use in soils with low bulk densities similar to those found in agriculture. Four highway test sites in Tennessee were instrumented with five-segment TDR probes in the soil subgrade and in the unbound aggregate sub-base (Rainwater et al. 1999). These materials are more dense than agricultural soils. After several months of data collection and field verification, the TDR predicted water contents and gravimetric water contents did not coincide. For this reason, a study was performed with the TDR equipment using each of the four test site subgrade soils and an unbound aggregate sub-base sample. Ten previously published TDR water content relationships were evaluated to determine which relationship most accurately predicted water content for the subgrade soils and for the unbound aggregate sub-base using the five-segment probe. During the course of the study, it was necessary to evaluate the manufacturer's relationship between the measured propagation time and the corrected propagation time, which accounts for the epoxy fill between the probe waveguides. The relationship was revised to reduce significant variation in corrected propagation times between segments.
The relationship between inverse signal velocity and soil water content proposed by Herkelrath et al. (1991) most accurately predicted water content for all subgrade soils; however, this relationship required the derivation of a soil-specific slope and intercept. The equation proposed by Baran (1994) most accurately predicted water contents for the unbound aggregate sub-base. Both of these expressions appear to provide a better prediction than the widely used Topp's relationship.
An Internal Instrumentation for Axial and Radial Strain Measurements in Triaxial Tests
Authors: Bésuelle P , Desrues J 
Published: February 2009

Abstract
A measuring device for axial and radial displacements in triaxial tests on soft rock specimens is described. Developed to optimize the detection of strain localization, the transducers have a linear response and a working range of a few percent. After a presentation of the manufacture and properties, detection of strain localization in the specimen during the compression test is discussed.
A Laboratory Apparatus to Measure Chemico-Osmotic Efficiency Coefficients for Clay Soils
Authors: Malusis MA , Shackelford CD , Olsen HW 
Published: February 2009

Abstract
A laboratory apparatus for measuring the chemico-osmotic efficiency coefficient, ω, for clay soils in the presence of electrolyte solutions is described. A chemico-osmotic experiment is conducted by establishing and maintaining a constant difference in electrolyte concentration across a soil specimen while preventing the flow of solution through the specimen. The chemico-osmotic efficiency coefficient is derived from a measured pressure difference induced across the specimen in response to the applied concentration difference. The effective diffusion coefficient (D*) and retardation factor (Rd) of the electrolytes (solutes) also can be determined simultaneously by measuring the diffusive solute mass flux through the specimen until steady-state diffusion is achieved. Experimental results using specimens of a geosynthetic clay liner subjected to potassium chloride solutions indicate that the measurement of ω may be affected by soil-solution interactions, as well as by changes in the induced chemico-osmotic pressure difference due to solute diffusion. As a result, ω should be evaluated using the induced pressure difference at steady state. The time required to achieve a steady-state response in induced pressure difference is related to the time required to achieve steady-state diffusion of all solutes, and may be affected by the circulation rate at the specimen boundaries. The circulation rate should be sufficiently rapid to minimize changes in the boundary concentrations due to diffusion, but sufficiently slow to allow measurement of solute mass flux at the lower concentration boundary for evaluating D* and Rd.
LVDT Based System for the Measurement of the Prefailure Behavior of Geomaterials
Authors: Da Re G , Santagata MC , Germaine JT 
Published: February 2009

Abstract
This paper describes a device that can accurately measure the small strain behavior of geomaterials in the triaxial apparatus. It makes use of two miniature submersible linear variable differential transformers (LVDTs) mounted on a pair of yokes which clamp onto the soil specimen. A highly stable, low noise, custom designed signal conditioning system completes the design. The result is a device capable of consistently resolving displacements of less than 0.1 microns corresponding to strains of less than 0.0002% for standard sized (3.6 cm × 7.6 cm) triaxial specimens. The system is simple in design, can be easily implemented in existing triaxial equipment, and thus may represent a commercially viable solution for the investigation of the small strain behavior of soils in the triaxial apparatus.
Along with a description of the mechanical and electrical system, the paper presents the results of proof testing performed to assess the stability and linearity characteristics of the system under a wide range of temperature and pressure conditions. These tests demonstrate the device's versatility and its ability to measure true axial strains. Recent modifications to the existing triaxial equipment, introduced to improve the investigation of small strain behavior in geomaterials, are also discussed.
Finally, the performance of the device is illustrated with results of tests on Resedimented Boston Blue Clay (RBBC) and frozen Manchester Fine Sand (MFS). These geomaterials differ in stiffness by more than two orders of magnitude and establish a range in behavior that encompasses that of most soils. Test results confirm that the measuring system can provide a detailed characterization of the pre-failure behavior of soils in triaxial compression.
A Potential Model for Compaction Evaluation of Piedmont Soils Using Dynamic Cone Penetrometer (DCP)
Authors: Gabr MA , Coonse J , Lambe PC 
Published: February 2009

Abstract
The potential use of the Dynamic Cone Penetrometer (DCP) as a compaction quality control tool is investigated in this study. The DCP is a simple device and relatively inexpensive to operate. Results from a laboratory testing program performed on three piedmont residual soils with appreciable fine content (&gt; 60%) yielded correlation patterns for the estimation of moisture content (w) and dry unit weight (γdry), based on the DCP penetration rate (PR). The PR-liquidity index (LI) data were best correlated with an equation in the form of LI = A Log PR-Bm. For the test soils, A was equal to 0.65 and Bm = 1.2. On the other hand, the PR-degree of saturation (S) data were best correlated with the equation in the form of S = 1 − eCm*PR with the Cm coefficient estimated equal to −0.065. Using the principles of soil mechanics, w and γdry are calculated based on the predicted LI and S values, respectively. Using the water content and unit weight models, and on the average, the water content was underpredicted by 0.2% and the dry unit weight was overpredicted by 0.3 kN/m3. The developed model parameters are expected to vary for different soil types as well as compaction effort and a field calibration procedure in which moisture contents and dry densities are evaluated by alternative means, on a limited scale, is recommended.
Effects of Installation Method on Sand Compaction Piles in Clay in the Centrifuge
Authors: Lee F-H , Ng Y-W , Yong K-Y 
Published: February 2009

Abstract
The effects of the method of installation of centrifuge model sand compaction piles (SCPs) in soft clay are studied. The comparative study involves the frozen pile method, a 1-g displacement method, and a high-g displacement method. The results show that, although all the SCP-improved models exhibit higher strength compared to the unimproved models, both displacement methods confer additional enhancement in strength to ground improvement, which was not present in the frozen pile models. In addition, wavy settlement patterns were also observed in the frozen pile models, but not in the displacement models. The observed differences were explained by the postulated differences in stress states of the improved models. For the frozen pile models, thawing during reconsolidation was postulated to lead to a reduction in effective lateral stress, resulting in further softening of the clay. On the other hand, the cavity expansion effect caused by the displacement methods was postulated to lead to a set-up in the strength of the clay, thereby resulting in better integrity in the response of the improved ground to loading.
Experimental and Data Analysis Techniques Used for High Strain Rate Tests on Cohesionless Soil
Authors: Abrantes AE , Yamamuro JA 
Published: February 2009

Abstract
Experimental methods used to subject drained triaxial compression axisymmetric test specimens composed of cohesionless soils to very high strain rates and analyze the resulting data are presented. Included is the use of a custom gravity drop-frame loading system to generate the high strain rates and a custom square triaxial cell to minimize optical distortion. Methods to collect and analyze the experimental results are also presented. High-speed film photography, coupled with digital image analysis techniques, are used to capture specimen deformations. Experimental issues such as image analysis of specimens, optical corrections, time synchronization of photographic images with data acquisition, inertial effects, global versus local strain measurements, axisymmetric shape of the specimen during deformation, and membrane compliance are examined by analyzing test results that were performed at high strain rates.
Shear-Wave Velocity to Determine Vertical Stress Share on Column-Sand Samples
Authors: Blewett J , Woodward PK 
Published: February 2009

Abstract
The increased rigidity of vibro-replacement stone columns in liquefiable soils offers the potential for liquefaction mitigation. This paper proposes a laboratory method to facilitate an investigation of this parameter. Shear-wave velocity data are used to obtain the vertical load distribution between loose sand and gravel column in composite columnar triaxial samples under static and cyclic loading. Significant reductions in cyclic stresses applied to the loose sand are obtained, offering the potential for the optimization of the design of vibro-systems to include load share benefits.
A Comparative Evaluation of Various Additives Used in the Stabilization of Expansive Soils
Authors: Al-Rawas AA , Taha R , Nelson JD , Al-Shab BT , Al-Siyabi H 
Published: February 2009

Abstract
This paper investigates the effectiveness of using cement by-pass dust, copper slag, granulated blast furnace slag, and slag-cement in reducing the swelling potential and plasticity of expansive soils. The soil used in this study was brought from Al-Khod (a town located in Northern Oman) where structural damage was observed. The first stage of the experimental program dealt with the determination of the chemical, mineralogical, and geotechnical characteristics of the untreated soil. The soil was then mixed with the stabilizers at 3, 6, and 9% of the dry weight of the soil. The treated samples were subjected to liquid limit, plastic limit, swell percent, and swell pressure tests. Furthermore, the cation exchange capacity, exchangeable cations (Na+, Ca++, Mg++, and K+), and pH of the treated samples were also measured. The study showed that copper slag caused a significant increase in the swelling potential of the treated samples. Other stabilizers reduced the swelling potential and plasticity at varying degrees. The study further indicated that cation exchange capacity and the amount of sodium and calcium cations are good indicators of the effectiveness of chemical stabilizers used in soil stabilization.
Predicting the Shear Strength Envelope of Unsaturated Soils
Authors: Rassam DW , Cook F 
Published: February 2009

Abstract
Determining the shear strength envelope of an unsaturated soil involves a sophisticated and time-consuming testing program. Hence, it is advantageous to minimize the number of tests required to establish the envelope. In this paper, a power additive function is adopted to predict the shear strength envelope of unsaturated soils from knowledge of the unsaturated shear strength at residual suction, the effective stress friction angle for saturated conditions, and the soil-water characteristic curve. Two boundary conditions are required to quantify the two fitting parameters of the function. The first is φb = 0 at residual suction, and the second is the contribution of matric suction to the shear strength at residual suction, which should be experimentally evaluated. The validity of the method is tested for a number of unsaturated shear strength data covering a wide range of suctions. Good agreement was found to exist between the predicted envelopes and the experimental data. The method requires only one experimental evaluation of the unsaturated shear strength and is most suitable for coarse- to medium-grained soils where the residual suction may be achieved reliably in the laboratory.
Determination of Trace Amounts of Sediment in Gas-Oil
Authors: Babitz M , Rocker A 
Published: February 2009

Abstract
The proposed method is suitable for quantitative determination of trace amounts of sediments in gas-oil on the order of 0.001 percent in the presence of water. It is a modification of the ASTM Standard Method of Test for Water and Sediment in Crude Oils and Fuel Oils by Centrifuge (D 1796) and the ASTM Standard Method of Test for Water and Sediment in Distillate Fuels by Centrifuge (D 2709) and uses a 1:1 mixture of toluene and isopropanol as solvent for centrifugation. Its repeatability is on the order of 0.002 percent.
Fatigue Behavior of Copper with Intermediate Surface Layer Removal
Authors: Nakano Y , Sandor BI 
Published: February 2009

Abstract
The effect of single and periodic intermediate surface layer removal on the fatigue behavior of oxygen-free, high-conductivity copper was studied in the life range of 105 to 2 × 106 cycles. The fatigue tests were conducted at room temperature, in tension-compression, under load control, and without mean load. The surface layer removal was accomplished by electropolishing. The variables of the test conditions were the engineering stress range, the average grain size, and the atmosphere (air and argon gas).
A single treatment of removing all the surface markings (caused by fatigue) during the life increased the subsequent fatigue life significantly. The largest increase in life was obtained after the largest period of precycling, which was about 80 percent of the standard life. The average plastic strain ranges after the polishing treatments were measured. The fatigue lives after polishing were strongly dependent upon the depth of the removed surface layer.
Periodic treatments to remove all the surface markings during the life also increased the fatigue life. Removal of all the surface markings after every 80 percent of the standard life increased the life by a factor of ten.
Stress-Relaxation Characteristics in Tension of High-Strength, High-Conductivity Copper and High Copper Alloy Wires
Authors: Fox A 
Published: February 2009

Abstract
The ability of pressure-type electrical connections to remain stable and reliable over long periods of time depends in large measure on the stress-relaxation characteristics of the conductor and the connector material. For applications such as the miniaturized solderless wrapped connection, traditionally made with copper No. C110 (ETP copper), the relaxation of the conductor is far greater than that which occurs in the terminal; hence, for this type of termination the behavior of the conductor material governs the stability of the termination.
Miniaturization of telephone equipment and the associated increase in ambient operating temperatures requires improved conductor materials which, in addition to having adequate tensile strength, ductility, and high electrical conductivity, are able to resist stress relaxation at these higher temperatures. Based on these considerations the tensile stress-relaxation behavior of several 0.255-mm diameter (30 AWG) high-strength, high-conductivity copper and copper alloy conductors were studied in the temperature range 23°C to 149°C (73°F to 300°F) for a time period extending to 10,000 h. Stress-temperature-time relationships are shown to follow Arrhenius behavior, thus permitting a choice of realistic accelerated aging test requirements for connections made with these copper alloy conductors.
Since high-speed production of these conductor materials possibly may require in-line strand annealing procedures, a comparison of the stress-relaxation behavior of commercially processed strand annealed samples with that of laboratory processed batch annealed material, as well as a comparison of the effects of gage size on stress relaxation [0.511-mm (24-AWG) diameter versus 0.255-mm (30-AWG) diameter wires] was included in this study. Since no significant size effects were observed, available stress-relaxation data on a number of 0.511-mm (24-AWG) diameter high-strength, high-conductivity copper and copper alloy conductor materials are also included for convenient reference.
Contact Angle of Zinc on Some Ceramic Materials and Metals
Authors: Kelley JE , Harris HM 
Published: February 2009

Abstract
Measurements were made of the contact angle of molten zinc drops on fifteen ceramic materials and four metals in high-purity helium and carbon monoxide atmospheres. Zinc of 99.9999-percent purity did not wet the oxide materials, glass-type coatings, or graphite; all contact angles were greater than 90 deg at 500 to 700°C in helium and 500 to 800°C in carbon monoxide. Materials tested that were most resistant to wetting by zinc were ZnO sinter, glazed fireclay, graphite, and mullite.
Mechanical Properties of Epoxy Impregnated Concrete
Authors: Whiting DA , Blankenhorn PR , Kline DE 
Published: February 2009

Abstract
Concrete has been impregnated with a particular epoxy system using a combined vacuum-pressure technique. Compressive modulus and compressive strength of these concretes were determined and found to be a function of total porosity. Results are compared with data previously reported for polymer concretes based on other monomer systems.
Dependence of Fatigue Notch Factor on Plasticity and Duration of Crack Growth
Authors: Gowda CVB , Leis BN , Smith KN 
Published: February 2009

Abstract
The effects of several factors which influence the magnitude and variation with life of fatigue notch factor (Kf) are discussed in this paper. Plasticity at the roots of stress raisers is known to have the most dominant influence on the variation of Kf when a failure criterion of fatigue crack initiation is employed. When a failure criterion other than cycles to crack initiation is employed, the duration of crack propagation becomes a significant factor in the determination of magnitude and variation of Kf. The duration of crack propagation is viewed as a primary influence on the magnitude of Kf since the increase in propagation duration with increasing theoretical stress concentration factor (Kf) accounts in part for the decrease in notch sensitivity. New evidence is given to the influence of the above two factors on Kf and an attempt is made to add to the understanding of fatigue process in notched components.
A Test Procedure for Determining the Influence of Stress Ratio on Fatigue Crack Growth
Authors: FitzGerald JH , Wei RP 
Published: February 2009

Abstract
A test procedure is outlined by which the rate of fatigue crack growth over a range of stress ratios and stress intensities can be determined expeditiously using a small number of specimens. This procedure was developed to avoid or circumvent the effects of load interactions on fatigue crack growth, and was used to develop data on a mill annealed Ti-6Al-4V alloy plate. Experimental data suggest that the rates of fatigue crack growth among the various stress ratios may be correlated in terms of an effective stress intensity range, Δ Keff, at given values of Kmax.
This procedure is not to be used, however, for determining the corrosion fatigue crack growth characteristics of alloys when non-steady-state effects are significant.
Sources and Magnitude of Errors in the Measurement of Coating Thickness with the Double-Beam Interference Microscope
Authors: Saur RL 
Published: February 2009

Abstract
An analysis was made of three factors (fringe width, phase change, and surface roughness) which contribute to errors in measurement of coating thickness with a double-beam interference microscope. Excluding any unpredictable contributions made by surface roughness, a theoretical analysis based on a literature search revealed that the total of the two remaining errors will not exceed ±0.19 μm (±0.0076 mil) if either the coating or its substrate is a metal. If both are metals, the error will not exceed ±0.12 μm (±0.0048 mil). Measurements were made on a few samples of common coating systems. The errors experienced were much less than the above theoretical values, and would not normally contribute significantly to measurements with the double-beam interference microscope.
The Effect of Cement Properties and the Thermal Compatibility of Aggregates on the Strength of Accelerated Cured Concrete
Authors: Orchard DF , Jones R , AL-Rawi RS 
Published: February 2009

Abstract
Most research work on the effect of the thermal expansion of the constituents of concrete has concentrated chiefly on hardened concrete. Its resistance to heating and cooling and to freezing and thawing has been used for purposes of assessment. The works of different investigators have led to considerable contradiction and no definite conclusion can be drawn on the effect of differences between the coefficients of thermal expansion of the constituents of concrete. Findings show effects on the durability under repeated cycles of freezing and thawing and the compressive strength of concrete subjected to temperature change. There is some evidence that the relative expansions of the constituents of fresh concrete cause a reduction of its ultimate strength under conditions of accelerated curing.
In the present research, when electric curing was adopted, the complete elimination of any temperature gradients throughout the test specimens was effected by precisely controlled conditions. This made it easier to detect small differences as the conditions were changed.
The factors investigated were the ratio of the strengths obtained by (1) one-day accelerated curing and 28-day normal curing and (2) one-day accelerated curing plus 27-day normal curing and 28-day normal curing.
It was found that coarse aggregates having a low coefficient of thermal expansion caused a significant drop in the one-day accelerated cured compressive strength. The coefficient of thermal expansion of the coarse aggregate did not have much effect on the 28-day accelerated cured strength. It was thought that this was due to autogenous healing during the 27 days of normal curing, rectifying any cracking caused through stresses arising from thermal incompatibilities during the one day of accelerated curing. Residual expansion after heating and cooling of certain aggregates was liable to cause decreases in strength. Further evidence is given of the importance of the C3A content of cement in determining the ultimate strength obtained when the concrete is subjected initially to accelerated curing.