bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Nature of the Immediate Reaction of Lime in Treating Soils for Road Construction
Authors: Verhasselt AF 
Published: March 2009

It is now well-known that the geotechnical characteristics of wet cohesive soils are improved rapidly by adding lime (immediate effects) and that, subsequently, the mechanical characteristics of the compacted mixture generally develop in course of time (long-term effects). Whereas the pozzolanic nature of the slow reactions which result in long-term stabilization has been recognized, that of the immediate reactions still remains a point of controversy. By replacing lime with an equivalent amount of various mineral substances that may react in a similar manner, an attempt was made to obtain the same immediate effects as those produced by incorporating lime into wet, silty soil. The tested substances are: the hydroxides of strontium, barium, and sodium; the sulphates of calcium and aluminum; and calcium chloride.
The results show that the whole of immediate effects are obtained only when alkaline-earth ions (calcium, strontium, or barium) and hydroxyl ions are present at the same time. The hypothesis of the clay particles being linked as a result of physico-chemical adsorption of calcium hydroxide [Ca(OH)2] molecules or CaOH+ ions accounts well for the experimental observations.
Properties of a Treated-Bentonite/Sand Mix in Contaminant Environment
Authors: Wu JY , Khera RP 
Published: March 2009

This research was conducted to study the changes in the properties of a mixture consisting of a chemically treated bentonite and sand in contaminant environments. Seven chemicals and their aqueous solutions were used. The effects of chemicals on the soils were stressed by directly introducing the chemicals to the soil specimens and observing the changes in their properties over one year.
Index tests included expansion and sedimentation tests. These tests provided a good measure of soil-chemical compatibility. Permeability measurements were made using a consolidometer permeameter, a flexible wall permeameter, and a triple ring permeameter which was developed for this research. The triple ring permeameter preserves the advantages and compensates for the limitations of other types of permeameters.
At consolidation pressures most likely to prevail in a slurry wall, the coefficient of permeability increased with increasing concentration of the chemicals. If a soil showed less expansion in a given liquid, its permeability was observed to increase more. Tests with aniline, phenol, toluene, and 1,1,1-trichloroethane did not yield any significant adverse effect on the permeability. The largest increases were observed with sodium hydroxide. With the same chemical solutions the increases in permeability were considerably smaller at a confining pressure greater than 100 kPa.
A four-phase soil system is proposed which incorporates the effect of semi-solid expanded volume of the bentonite. Two parameters, er and ef, are defined which can account for the changes in the expansion of the bentonite resulting from the influence of chemicals. The coefficient of permeability decreases with increases in er and ef values.
Effect of Sulfate Contamination on the Volume Change Behavior of Bentonite
Authors: Sridharan A , Rao SM , Gajarajan VS 
Published: March 2009

This paper reports the influence of the principal anionic contaminant of acid rain deposition, namely sulfate ion, on the index, swelling, compressibility, and permeability characteristics of bentonite. Adsorption of sulfate ion leads to edge-to-edge bonding of bentonite particles; the occurrence of such a reaction mode throughout the clay matrix mobilizes an edge-to-edge flocculated fabric.
The liquid limit, swelling magnitude, and swelling pressure of bentonite clay markedly increases on sulfate adsorption. It is likely that, for the anion-treated clay, besides the growth of a diffuse double layer, water is imbibed by entrapment in the large void spaces of its flocculated structure, thus explaining the higher liquid limit and swelling magnitude of the treated specimen. Further, it is considered that the higher degree of particle interference associated with the flocculated fabric of the anion-treated clay resists particle rearrangement under external stresses more effectively than the oriented array of the natural clay, accounting for the larger swelling pressure of the former specimen. The greater particle interference associated with sulfate clay presumably is responsible for its consolidation curve being positioned above that of the natural clay.
The de/d (log p) versus pressure plots indicated higher compressions for the anion-treated clay at any given pressure increment. Possibly the anion-treated clay with a flocculated fabric undergoes greater particle reorientation under a given load, explaining its higher compressibility. The similar ranges of permeability coefficients observed for the natural and anion-treated clays suggested that the changes in clay fabric brought about by anion adsorption is not significant enough to influence the permeability of bentonite clay.
The Effect of Heating on Engineering Properties of Clays
Authors: Wang MC , Benway JM , Arayssi AM 
Published: March 2009

The effect of heating on gradation, specific gravity, plasticity characteristics, swelling, and shear strength properties of a kaolin and a bentonite were investigated. The test soils were heated in an electric furnace to different temperatures up to 600°C. The engineering properties were determined by following ASTM standard procedures.
Results of the study indicate that heating the kaolin to 400°C reduces the amount of swelling drastically. Further heating to 500°C causes a formation of larger particles, a drop of specific gravity, a change into nonplastic, and a substantial increase in shear strength of the kaolin. For the bentonite, larger particles are found when heated to 600°C. Also, at 600°C, the clay becomes nonplastic and nonexpansive and undergoes a moderate strength gain. Based on the results of the investigation, it is concluded that heating can be used to stabilize soft clay deposits effectively.
Pore Water Extraction—Comparison of Saturation Extract and High-Pressure Squeezing
Authors: Iyer B 
Published: March 2009

A study of the influence of the chemical environment on the engineering behavior of clayey soils warrants an understanding of the chemistry of the pore water present in the soil, together with the physico-chemical properties of the soil minerals. There are several techniques available for the extraction of the pore water from soil samples. Following a review of these techniques, two methods were considered suitable for the extraction of pore water from overconsolidated clay deposits. Pore water was extracted from several clay shales and bentonitic clays from western Canada using the high-pressure mechanical squeezing technique and the saturation extract technique during this study.
Based on the results of a previous study, it was expected that the pore water concentration determined using the saturation extract method would yield higher salt concentrations since the relationship between the concentration and the inverse of the water content is nonlinear. This phenomenon was confirmed in the present study. A comparison of the composition of the pore water extracted using the two techniques indicated that the saturation extract technique always yielded pore water with higher salt concentration. Based on this observation, it is concluded that the extrapolation of the pore water concentration at low moisture contents from known salt concentrations at higher (diluted) moisture contents should be viewed with caution.
A New Thermodilatometric Instrument for Thin Metallic Ribbons
Authors: Etchessahar E , Harmelin M , Debuigne J 
Published: March 2009

A thermodilatometer was designed allowing metallic specimens in the form of thin ribbon to be heated at slow heating rates (1 to 5°C min-1) from room temperature up to 1000°C in an ultra-high vacuum (10-7 Pa). This dilatometer is a direct type and highly sensitive; amplification coefficient is 25 000. The transparent silica specimen holder is of the tensile type and allows the specimen to be fixed in a unique plane of the space. The specimen is 40 mm in length and ≈50 μm thick. A tensile stress of ≈5×104 Pa is applied during the experiment. One or more strips can be used for each experiment.
This device was used for studying metallic glasses: Fe78B13Si9 and CuxZr(100-x) (x = 33, 40, and 46). Thermal expansion coefficients were determined on heating and cooling. Isothermal annealings were also performed in situ in the dilatometer. On heating, the “as-quenched” ribbons, structural relaxation, Curie point, glass transition, and crystallization are successively evidenced on the dilatometric curves. Structural relaxation results in a progressive and small shrinkage of the specimens (ΔL/L &lt; -4 × 10-4). Curie point results in sharp shrinkage. Glass transition is manifested by the creep of the specimen (ΔL/L ≈ +2.0 × 10-3), and crystallization of the amorphous phase results in a large shrinkage (ΔL/L ≈ - 1.00 × 10-3).
Relaxation rate, Curie point, glass transition, and crystallization of the specimens were also determined by differential scanning calorimetry (DSC). The irreversibility of structural relaxation below glass transition is well evidenced by DSC and thermodilatometry.
Thermomechanical Analysis: Advances in the State of the Art
Authors: Sauerbrunn SR , Gill PS 
Published: March 2009

This presentation will describe the new DuPont 2940 thermomechanical analyzer (TMA). The 2940 TMA is a thermal analysis and mechanical characterization tool that measures the mechanical properties of a material as a function of time, temperature, and force. The instrument offers all of the traditional capabilities of TMA, but with total automation, increased sensitivity and enhanced force control. Specimen measurement and dimension change are controlled by a stepper motor and linear variable differential transformer (LVDT).
Focusing on higher performance polymer systems, this presentation will explore their thermomechanical properties. Application techniques easily managed by TMA include the coefficient of thermal expansion (CTE), glass transition Tg, and three-point flexural bending. The influence of thermal history and processing effects on these properties will be reported on specific polymers and composites.
Asphalt Cement Characterization by Thermomechanical Analysis
Authors: Lee D-Y , Enustun BV , Kim S-S 
Published: March 2009

Thermomechanical analysis (TMA) techniques were used to characterize 60 original and aged asphalt cements. The objectives were to find better methods to characterize asphalts at low temperatures, to predict low-temperature cracking potentials, and to develop correlations between thermal properties of asphalts and their field performance for specification purposes.
A DuPont 943 Thermomechanical Analyzer was used in conjunction with a DuPont 1090 Thermal Analyzer Programmer. Glass transition temperatures of some asphalts, both original and aged, were also determined by both thermomechanical and differential scanning calorimetry (DSC) techniques. Although a number of test variables were examined, the results presented for TMA were run under expansion mode between -70 and 25°C, and those presented for DSC were obtained by scanning between -80 and 80°C, both at heating rate of 5°C per min. Thermal analysis results were correlated with Theological properties and molecular size distribution of asphalts based on high performance gel permeation chromatography (HP-GPC) profiles.
Glass transition temperatures varied between -22.5 and -35.0°C for original asphalts and between -22.0 and -37.0°C for aged asphalts, depending on viscosity grade, source, and rate of heating. Reasonable correlations were obtained between glass transition temperature determined by DSC and TMA methods. It was also found that TMA parameters correlated with ring-and-ball softening point, predicted cracking temperature, temperature corresponding to critical stiffness of 138 MPa (20 ksi) at long loading time, and molecular size distribution data.
Multipulse Laser-Induced Failure Prediction for Mo Metal Mirrors
Authors: Becker MF , Ma C , Walser RM 
Published: March 2009

In combination with known thermomechanical fatigue data for Mo, we have applied the Transient Photothermal Deflection (TPD) technique to develop a model for the N-on-1 damage of Mo mirrors to predict their multipulse lifetimes. In laser-damage experiments to verify the model, mechanically polished Mo mirrors were irradiated with 10 ns Nd:YAG laser pulses at 1064 nm at a 10 Hz rep rate. In the TPD experiments, the approximately 600 μm diameter Nd/3YAG laser spot was probed off axis by a smaller HeNe laser beam whose deflection was detected by a fast bicell photodetector and amplifier. Digitized photodetector waveforms indicated that the surface angular deflection could be converted into surface displacement. In addition, thermal modelling of the vertical heat distribution enabled the peak surface-deflection signal to be converted into peak surface temperature. The thermomechanical model was verified by both the experimental and model results.
Conventional mechanical fatigue data for Mo were used to derive a predictive equation for the laser-accumulation lifetime of Mo mirrors. Experiments were performed with one to 104 pulses per site yielding laser-damage thresholds and accumulation curves. The accumulation behavior predicted from measurements of mechanical fatigue was in excellent agreement with the measured behavior. It is possible that data on high-cycle (&gt;106) mechanical fatigue can be used to predict the performance of optical surfaces at equally large values of N. Furthermore, a single-pulse TPD measurement of peak deformation at a subthreshold laser fluence, in conjunction with mechanical fatigue data, may be used to estimate the safe operating fluence for a component in a multipulse laser environment.
High Threshold HR Coatings at 1064 nm
Authors: Rainer F , De Marco FP , Hunt JT , Morgan AJ , Mott LP , Marcelja F , Greenberg MR 
Published: March 2009

We have conducted an extensive series of laser damage measurements on highly reflective (HR) dielectric coatings which have yielded 1064-nm thresholds as high as 40 J/cm2 for 8- to 10-ns pulses at pulse-repetition frequencies (PRF) of 10 Hz. Moreover, by laser conditioning these coatings with sub-threshold pulses, the thresholds of some coatings were raised to levels exceeding 70 J/cm2. These are the highest threshold dielectric HR coatings that we have tested in this regime.
The coatings were originally developed to produce HR-overcoated metal mirrors for free-electron-laser (FED applicationsat high PRF. Our tests included coatings deposited on both dielectric substrates and molybdenum (Mo) substrates. In each category we also examined coatings with a pre-coat of Mo between the substrate and the HR stack. The improved dielectric HR stacks effectively shielded the Mo from the laser irradiation so that the thresholds of virtually all Mo samples exceeded levels of the best dielectric-enhanced and dielectric-HR-coated metal mirrors we have tested to date.
In addition to the low PRF measurements, we also conducted 1064-nm damage tests at 6-kHz PRF using 65-ns pulses from the Kilroy damage test facility. The coatings survived thermal loading of fluences ranging from 2 to 10 J/cm2 with respective small spot sizes on the order of 1.2 to 0.3 mm (1/e2 diameter).
Laser Conditioning and Electronic Defects of HfO2 and SiO2 Thin Films
Authors: Kozlowski MR , Staggs M , Rainer F , Stathis JH 
Published: March 2009

Multilayer HfO2/SiO2 high reflectors (HR) and polarizers show a permanent increase in their 1064-nm damage thresholds following laser conditioning at subthreshold fluences. Threshold increases of 2–3x are typical. In an effort to better understand the conditioning effect we have made laser conditioning and electronic property measurements on single layers of these two materials. The laser damage threshold of 1-μm thick e-beam deposited SiO2 was increased by laser conditioning for wavelengths ranging from 355 to 1064 nm. The damage threshold of HfO2 single layers was not influenced by sub-threshold illumination.
As-deposited thin films of a-SiO2 are known to contain paramagnetic electronic defects. We have used electron paramagnetic resonance (EPR) to study the concentrations and types of defects present in single layer and multilayer films of HfO2 and SiO2. E' and oxygen hole centers with concentrations on the order of 1017/cm3 have been measured in the SiO2 layers. A previously unreported defect has been observed for HfO2. The concentration of defects was studied both before and after laser conditioning and damage with 1064-nm photons. These electronic structure measurements are discussed in relation to an electronic defect model for laser conditioning of dielectric multilayers.
Reactive Ion-Beam-Sputtering of Fluoride Coatings for the UV/VUV Range
Authors: Schink H , Kolbe J , Zimmermann F , Ristau D , Welling H 
Published: March 2009

Fluoride coatings produced by thermal evaporation suffer from high scatter losses, ageing and cracking due to high tensile stress. These problems impose severe limitations to the production of low loss multilayer coatings for the VUV range. A key position for improved performance is the microstructure of the layers.
The aim of our investigations is to improve the microstructure of AlF3- and LaF3-films by ion-beam-sputtering. Scatter measurements of single layers revealed lower values for IBS than for boat evaporation. Unfortunately, sputtered fluoride films have high absorption losses caused by decomposition of the coating material.
By sputtering in reactive atmospheres and annealing we were able to reduce the absorption losses significantly. Antireflective as well as high reflective coatings were produced. Reflection and transmission values were obtained with a VUV-spectrophotometer. Damage tests at the 193 nm ArF laser wavelength were performed at the Laser-Laboratorium Göttingen.
Finite Element Analysis of the Transient Behavior of Optical Components under Irradiation
Authors: Borik S , Giesen A 
Published: March 2009

With increasing laser power the transient behavior of the optical components becomes more and more important, giving rise to investigations in this field, e.g. [1,2,3]. Especially the time dependence of the optical properties which influence the laser beam parameters is of interest.
In this paper the heating of optical components caused by the absorption of a small part of the laser power as well as the resulting deformation of the phase front of the laser beam have been studied with finite element analysis. For this, the spatial temperature profile, the mechanical deformation and the stress of the optical component have been calculated as a function of laser power, laser mode profile and irradiation time. Using the temperature dependence of the index of refraction, the spatially resolved optical path difference compared to the unirradiated component has been calculated with a ray tracing algorithm.
The results for various optical components (mirrors, windows; coated and uncoated) are given and compared to experimental investigations.
Three-Dimensional Elastic-Plastic Analysis of Small Circumferential Surface Cracks in Pipes Subjected to Bending Load
Authors: Franco C , Gilles P 
Published: March 2009

This study presents the elastic-plastic behavior of a circumferentially surfacecracked pipe using the finite element method based on a three-dimensional model.
The action of a pure bending load on the pipe is analyzed for three crack depths with a/t equal to 0.25, 0.5, and 0.75, and their eccentricities, a/c, being 0.2, 0.4, and 0.6, respectively.
The material obeys a Ramberg-Osgood power law. The goals are to determine the stressstrain fields and the values of J on the crack front, to define the different plastic deformation stages reached as the load on the crack is increased, and to validate the Central Electricity Generating Board (U.K.) (CEGB) two-criteria rule for circumferential surface flaws on the basis of the J results.
Three-Dimensional Analysis of Thermoelastic Fracture Problems
Authors: Chen W-H , Huang C-C 
Published: March 2009

This paper deals with three-dimensional thermoelastic fracture problems using both analytical and numerical results. The analytical temperature distribution of an infinite solid with an embedded elliptical insulated crack subjected to an uniform heat flow solved by the authors is first described briefly to provide a verification for the three-dimensional finite element model with collapsed quarter-point singular elements around the crack front. To determine the thermal stress-intensity factors, the three-dimensional path-independent integrals that are physically the energy release rates per unit area of crack extension along respective directions of crack growth are employed and computed for three-dimensional realistic thermoelastic fracture problems.
To evaluate the influence of geometry and Poisson's ratio on the computation of temperature distributions and thermal stress-intensity factors for various thermal conditions, several representative examples are presented. The variations of pure and mixed-mode thermal stressintensity factors along the crack front are also studied for both through and part-through cracks in finite elastic solids.
Good agreements between the computed results and referenced solutions show the validity and accuracy of the present analysis.
The Needs of Users and Their Response to Materials Databanks
Authors: Hossain K , Barry T 
Published: March 2009

The commercial and design requirements for data at the conception of a product and at each stage of its design for processing, use and ultimate disposal place great demands on materials information. The breadth and depth of need are examined in relation to the ways in which they influence the choice of sources and types of data. It can be seen from this approach that those with the ability to draw on and make use of data from a wide range of sources have an obvious advantage in product innovation. A survey in the UK of the response of potential users of materials information systems is reviewed and possible solutions to user resistance examined.
A problem not exclusive to computer based systems of materials information lies in the near certainty that they contain errors and gaps in the data and have limited ranges of application. Moreover, if they are knowledge based or offer powerful facilities for predicting materials properties using models, due care has to be taken to ensure that they are not misused, leading to users obtaining erroneous solutions. For these reasons materials databases should provide traceability not only to data sources and software but also to user input.