bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Use of Thermal Analysis for the Evaluation of the Durability of a 24-Year-Old PVC Geomembrane
Authors: Cazzuffi DA , Venesia S 
Published: March 2009

The paper deals with the behavior of a geomembrane installed in 1963 for the internal waterproofing of a concrete pipe in a hydroelectric project. The type of geomembrane used was polyvinyl chloride (PVC), directly glued to the concrete support. The PVC geomembrane was directly exposed to the water; the water temperature in the pipe is usually 4°C in winter and 9°C in summer. The maximum waterspeed is 3 m/s, and the maximum water pressure is 0.6 MPa.
A first sampling of the PVC was carried out in 1973. A second sample was removed in 1987. The first sample was stored in a room for 14 years in controlled conditions. Thermal analysis on both geomembrane samples was performed in 1987 to assess the performance of the material over the 24-year period since installation.
Thermal-gravimetric analysis (TGA), differential scanning calorimetry (DSC), thermomechanical analysis (TMA), and dynamic mechanical analysis (DMA) were performed. Only small differences between the two samples were recorded, by TGA and DSC. However, TMA showed an increase in the softening temperature from 27°C in 1973 to 34°C in 1987. In addition, DMA showed an increase of the dynamic loss modulus of about 24% at the installed geomembrane operating temperature (from 4 to 9°C).
Laboratory Test Methods and Field Correlations for Predicting the Performance of Chip Seals
Authors: Stroup-Gardiner M , Newcomb DE , Epps JA , Paulsen GL 
Published: March 2009

Eighteen chip seal test sections were place in two states (Washington, Nevada). Four emulsions were used in the construction of these sections: cationic rapid set (CRS-2), cationic medium set (CMS-2), latex modified cationic rapid set (LMCRS-2), and a high float (HFE 100S). Variations in aggregates included: aggregate source, aggregate gradation, and precoating of aggregates.
Laboratory testing with the Vialet test was performed using construction materials and quantities. Laboratory test results were evaluated for the presence of excess aggregates and the set rate of the emulsions. Laboratory results were then compared to field comments.
Guidelines to avoid construction problems were outlined. In general, Vialet test results of less than 30% material retained indicate that problems with aggregate pickup on rollers could be expected. Results of less than 65% indicate potential damage by early brooming of new chip seals. Results greater than 80% provided satisfactory field performance after one month of low-volume traffic.
Generation of Smoke from Electrical Cables
Authors: Tewarson A , Khan MM 
Published: March 2009

Results are presented in this paper for the generation of smoke in terms of smoke yield, mass optical density, and specific corrosion constant for electrical cables during fire propagation. The data were measured in our studies on cable fire propagation. From this study, cables have been classified into three groups based on the Fire Propagation Index.
For Group 3 cables, self-sustained fire propagation rate is expected to be very rapid, and both thermal (heat) and nonthermal (smoke) damages are expected. For Group 2 cables, self-sustained fire propagation is expected to be less rapid than for Group 3 cables. Thermal and nonthermal fire damages are expected from Group 2 cables, although the severity is expected to be less than for Group 3 cables. For Group 1 cables, self-sustained fire propagation is expected to be difficult. In the presence of external heat fluxes or cable overheating due to electrical faults, fire propagation is expected to be sustained. For Group 1 cables, thermal fire damage is not expected; however, depending on the cables, nonthermal fire damage is expected. For Group 1A cables, nonthermal fire damage is not expected, and for Group 1B cables, nonthermal damage is expected.
The data from the study suggest that nonthermal fire damage is not expected if the following conditions are satisfied: (1) Fire Propagation Index is less than 10; (2) smoke yield is less than 0.30 g/g; (3) mass optical density is less than 0.11 m2/g; and (4) the specific corrosion constant of the cable is less than 0.92 × 10-6 μm/h ppm.
Contaminant Migration Effect on Dispersion Coefficients
Authors: Yong RN , Warith MA 
Published: March 2009

In this study, the variable nature of the dispersion coefficients of some typical contaminant ions is evaluated through experiments with leaching columns. Three clay soils were used: a natural clay soil (60% clay content) obtained near an operating landfill site, and laboratory-prepared kaolinite and illite clay soils. Sufficient quantities of the contaminant leachate obtained from the nearby operating municipal solid-waste landfill site were used for all the leaching tests. The ions chosen for evaluation in this paper were chloride, potassium, magnesium, and calcium ions.
The comparisons between predicted profiles using constant and variable dispersion coefficients with actual experimental concentration profiles indicate clearly that the use of variable coefficients provides for better correlation with experimental information. This is not surprising, since the varying concentration profiles (with pore volume penetration) reflect physico-chemical interactions which result in accumulation/retention processes measured in terms of the profiles. As the data show, the variable processes obviously will control transport and retention of the contaminant ions. The modeling thereof for transport will be reflected through the corresponding variable dispersion coefficients.
Changes in Soil Plasticity and Swell Caused by Electro-Osmosis
Authors: Thomas TJ , Lentz RW 
Published: March 2009

Theoretical and practical applications of electro-osmosis have been utilized for many years. Successful applications have included slope stability, dewatering, pile driving, and consolidation. In addition, electro-osmosis has been used in electrochemical injection applications, including the use of aluminum anodes and additives such as potassium chloride and aluminum acetate. Although there is a wide range of applications of electro-osmosis, there are many unknowns with respect to ion flow through soil and the resulting changes in soil properties.
The principal mechanism behind electro-osmosis is migrating ions. Oxidation and reduction take place at the electrodes as electrons are transferred in and out of the system. These reactions are associated with changes in soil pH which result in changes in the thickness of the double layer. In addition, the structure of alumino-silicates allows for the availability of certain ions for chemical reaction when subjected to an electrical gradient. These reactions may be dependent on pH or facilitated by a reduction in pH. Changes in thickness of the double layer as well as chemical reactions in the soil produce changes in soil properties, including plasticity and volume change characteristics.
Electro-osmosis was applied to a moderately swelling soil in the laboratory. The mass of soil treated was 12 by 12 by 6 in. Solution tanks on both ends of the soil contained the electrodes. A direct current power supply applied a constant voltage of approximately 16 V across the electrodes. Current, voltage, and pH were monitored throughout treatment. Electro-osmosis continued for a length of time sufficient to effect changes in soil pH near the anode and cathode.
Changes in soil properties were determined by performing Atterberg limits and swell tests on soil samples taken before and after electro-osmosis was applied. Samples were taken at different locations between the anode and cathode to determine variations in soil properties as a function of pH. Near the anode, where the soil pH decreased, significant changes in soil properties were noted. The plasticity index and swell were both found to decrease while the shrinkage limit increased. The changes, which are attributed to changes in the thickness of the double layer and to electrochemical hardening, indicate that soils considered questionable for use in engineering projects may be improved by electro-osmosis.
Ionic flow, changes in soil pH, and chemical reactions combine to produce changes in soil properties. As more is learned about the nature of these mechanisms, applications of electro-osmosis may be developed which fully utilize the electrokinetic phenomena.
Multiple-Pulse Damage of BK-7 Glass
Authors: Yoshida K , Yoshida H , Noda T , Nakai S 
Published: March 2009

High power glass laser systems for laser fusion use many BK 7 glasses, and the laser induced damage of this glass is a serious problem. Since the BK 7 glass is generally melted in platinum (Pt) crucibles, the laser damage due to metallic Pt particles occurs inside the glass. The Pt particles cause fractures when irradiated at a fluence higher than 3 J/cm2 with 1064 nm, 15 ns laser pulse. The size of the fracture increases with irradiation fluence, and the damaged glass has to be replaced.
In special cases, BK 7 glass is melted in ceramic crucibles, but there is a problem of cristobalite production inside the BK 7 glass. The laser damage threshold of cristobalite is about 4.5–5.5 J/cm2 with 1064 nm, 15 ns laser pulse.
We have found average damaged particles in BK 7 glasses melted in Pt and ceramic crucibles to be 200–400 and ̃ 10 particles per liter, respectively. At present, laser damage in BK 7 glass is being improved by changing a composition ratio of melting materials.
Use of Dome (Meniscus) Lenses to Eliminate Birefringence and Tensile Stresses in Spatial Filters for the Nova Laser
Authors: Pitts JH , Kyrazis DT , Seppala LG , Bumpas SE 
Published: March 2009

We document the concept and the design method for dome lenses that have a compressive pressure applied to the periphery. Dome (meniscus) lenses can eliminate both birefringence and tensile stresses if used in evacuated spatial filters where a pressure difference is present across the lenses. Calculations show that spatial filter birefringence is an insignificant 3 nm within the portion of a 740-mm Nova spatial filter dome lens illuminated by the laser beam. Membrane stresses are everywhere compressive, varying from -1.2 to -2.4 MPa, and are nearly uniform over the illuminated portion of the lens.
Eliminating sources of birefringence on the Nova laser could increase the energy on target with Type II/Type II frequency conversion from ̃50% to the ̃70% level attainable with Type I/Type II frequency conversion. Eliminating tensile stresses may reduce the damage and catastrophic failure that has occurred in some Nova spatial filter input lenses. The major disadvantage of using dome lenses on Nova is the cost of new lenses which could range up to $50,000 per lens for the material and $20,000 per lens for finishing.
Absorption Calorimetry and Laser Induced Damage Threshold Measurements of AR-Coated ZnSe and Metal Mirrors at 10.6 μm
Authors: Rahe M , Oertel E , Reinhardt L , Ristau D , Welling H 
Published: March 2009

Absorption and pulsed laser induced damage of antireflective coatings on ZnSe and high reflecting metal mirrors were studied. As deposition materials for the AR-coatings germanium, zinc sulfide, zinc selenide, cadmium selenide and different fluorides were selected. For protecting and enhancing of metal mirrors zinc sulfide and zinc selenide were used in conjunction with ThF4 as low index material. The films were deposited by thermal evaporation.
Absorption measurements were performed with the aid of a laser calorimeter and a cw CO2-laser. Single-shot and multiple-shot (prf, 3 Hz) damage thresholds were measured by a computer controlled test facility using 100 ns pulses from a TEA CO2-laser. The gaussian beam was focussed down to a diameter of 1.4 mm on the sample surface. A scatter measurement system and an on-line video microscope were applied for damage detection. Damage morphology was investigated by Nomarski- and scanning electron microscopy.
The Interaction of 1064 nm Photons with the Al2O3(1120) Surface
Authors: Schildbach MA , Hamza AV 
Published: March 2009

Low energy electron diffraction (LEED), Auger electron spectroscopy (AES), and electron energy loss spectroscopy (ELS) were used to characterize Al2O3(1120) surfaces before and after exposure to Nd:YAG 1064 nm, 1.17 eV photons. The clean and well-annealed (Ts&gt;1500K) surface exhibited a (12×4) LEED pattern. Irradiation of the surface with laser fluences of approximately 3.5 J/cm2,30% of the visible damage threshold, degraded the surface to the point that the (12×4) diffraction beams were no longer detectable. Characterization of the laser-irradiated surface by AES failed to show any departure from the (12×4) surface, unlike electron beam damage of alumina where the desorption of oxygen leaves metallic aluminum. However, subsequent annealing to 1700 K was sufficient to restore the original pattern. ELS of the (12×4) surface showed the presence of surface electronic states in the bulk band gap with energy losses between 3 and 5 eV.
Time-of-flight (TOF) spectra of laser-desorbed species obtained with a quadrupole mass spectrometer revealed that at fluences less than those leading to catastrophic surface damage, the desorbing flux was predominantly aluminum (atoms and ions). The energy of the desorbing aluminum was approximately 8 eV, the energy required to promote an electron from the valence band maximum to an exciton localized on the aluminum atom. At fluences which produce visible surface damage, oxygen molecules are observed in addition to aluminum in the desorbing flux.
Fabrication and Characterisation of Microwave Plasma Assisted Chemical Vapour Deposited Dielectric Coatings
Authors: Wood RM , Greenham AC , Nichols BA , Nourshargh N , Lewis KL 
Published: March 2009

A microwave plasma assisted chemical vapour deposition (MPACVD) process has been used to deposit modulated refractive index profile dielectric films to meet specific reflectance/transmittance coating characteristics.
The MPACVD process has been proven to allow the deposition of dielectric thin films of excellent optical quality which have lower scatter and less strain than most conventional coatings. An important feature of the process is that both the deposition rate and the composition of the film can be adjusted under computer control during the deposition process. This degree of control allows the deposition of both graded and even more complicated refractive index profiles. The technique therefore allows the successful realisation of highly sophisticated coating designs (e.g. Fourier).
The process has been used to fabricate a range of dielectric designs, including narrow band high reflectivity coatings with minimal sidebands, using silicon oxynitride on fused silica substrates. This paper discusses aspects of the MPACVD process, including deposition rate, control, uniformity and deposition quality, the Fourier design program and the characteristics of a range of coating trials. The measurements made have included optical, laser and limited environmental testing.
Analysis of Growing Ductile Cracks Using Computer Image Processing
Authors: Yagawa G , Yoshimura S , Yoshioka A , Pyo C-R 
Published: March 2009

This paper is concerned with a study of growing crack-tip behaviors in ductile materials using the hybrid experimental and numerical method by means of a computer image processing technique.
Here, a displacement field near a crack tip is first measured by the image processing technique. Combined with a finite element technique, the strain, the stress, the near-crack-tip J-integral, and the crack-tip singular field are evaluated from the measured displacement field. In this procedure, elastic unloading phenomena occurring around a growing crack tip, which may play important roles in the near-crack-tip behaviors, are also evaluated and are taken into account in evaluating the near-crack-tip J-integral.
The present method is applied to the analyses of a growing ductile crack in a tensile (CT) specimen made of Type 304 stainless steel. The transition behaviors of the crack-tip singular field, the elastic unloading, and the near-crack-tip J-integral in accordance with crack growth are discussed in detail through the comparison between experimental and theoretical results.
Assessment Of Health Risk from Wastes in Three Surface Impoundments
Authors: Moore RA 
Published: March 2009

A quantitative risk assessment was performed to estimate the potential for adverse health effects due to contaminants originating from wastes in three surface impoundments. A hypothetical exposure scenario was developed to assess potential risk. The scenario assumed chronic exposure to contaminants by daily consumption of groundwater from wells adjacent, and downgradient from the impoundments. Assumptions included future residential land use, utilization of shallow groundwater as a source of potable water, and steady-state conditions. These assumptions produced maximum exposure conditions and a conservative estimate of risk.
Methods follow Environmental Protection Agency (EPA) guidance for Superfund sites. Toxicity data were obtained from the EPA's Integrated Risk Information System (IRIS) and Health Effects Assessment Summary Tables (HEAST). Noncarcinogenic risk was expressed by comparing the reference dose (RfD) for chemicals of concern to estimated intakes. Carcinogenic risk was expressed as the probability of an individual developing cancer during a lifetime of exposure at the specified dose. Uncertainties associated with the risk assessment are presented and discussed.
Reducing the Number of Chemicals of Potential Concern: Four Case Studies
Authors: Huff DR , Tesch LA 
Published: March 2009

This is a comparative study that evaluates various methods for reducing the number of chemicals of potential concern in baseline risk assessments. The methods of reducing the number of chemicals of potential concern that were evaluated are the indicator score method (OERR 1986), grouping of chemicals by class, evaluating frequency of detection, and the concentration-toxicity screening method (OERR 1989). The evaluation consisted of comparison of quantitative risk assessment results for four case studies. Seven quantitative risk assessments were completed for each case study, six using a reduced subset of chemicals of potential concern and the seventh using all of the chemicals of potential concern. The six subsets were determined by using each of the four methods separately and two combinations of the methods.
The estimated risks for the subsets of chemicals of potential concern were generally equal to or less than the risks for the entire set of chemicals of potential concern. Carcinogenic risks were decreased in ten of the twenty-three test cases. Each of these decreases was less than an order of magnitude (10 times). Also none of the decreases reduced the carcinogenic risks to less than 10-4. This is significant since 10-4 represents the excess lifetime cancer risk which generally warrants remedial action (OSWER 1991a). Noncarcinogenic hazard indices were also decreased in ten of the twenty-three test cases. However, the hazard indices remained above one, the level of concern (OSWER 1991a), in all cases.
Apparatus for Thrust Wear Testing of Advanced Tribological Materials
Authors: Horman SL , Eyre RK 
Published: March 2009

This paper examines an apparatus developed for use in the wear testing of advanced bearing materials. A brief review of the applications of polycrystalline diamond as a tribological material is given as background for the development of the apparatus.
The apparatus tests materials in a sliding thrust wear mode in an area contact configuration. Cylindrical specimens are located on a concentric circle pattern, and the flat ends are mated together.
Through testing materials on this apparatus, certain tribological information is obtained concerning wear rate, friction coefficient, and threshold stress at various operating parameters. A review describes some of the testing performed on the apparatus as well as the results obtained in the testing of the various advanced tribological materials.
Predicting the Potential for Arsenic Contamination from Spent Gold Ore
Authors: Peterson ER , Luce RW , Jenkins CB 
Published: March 2009

Experiments were conducted on pilot study spent tuffaceous ore and native soils to predict arsenic teachability and subsequent attenuation from a proposed spent ore pile at an Idaho gold mine. The experiments were patterned after the graded serial batch extraction tests developed by Houle and Long and were designed to mimic the leachate movement through time and space conditions not attainable by column tests. Each extraction sequence involved consecutive contact with three batches of spent ore followed by three batches of soil. Four different samples of soil collected from the proposed mining site were tested in this manner. Solution aliquots were taken from each batch, filtered, and analyzed for arsenic and pH. Four extraction sequences were run for each soil type at increasing liquid-to-solid ratios to simulate increasing durations of leaching and attenuation. A total of 16 extraction sequences were conducted.
Analytical results of the solution aliquots showed an increase in arsenic concentrations on contact with successive batches of ore, but a decrease in concentration after contact with soil batches. For the conditions simulated, adsorption and precipitation by natural soils would prevent contamination of ground and surface waters. The results are consistent with the known aqueous geochemistry of arsenic.
A Field-Scale Study of the Use of Paper Industry Sludges as Hydraulic Barriers in Landfill Cover Systems
Authors: Maltby V , Eppstein LK 
Published: March 2009

Four field-scale landfill cover test cells have been constructed in order to facilitate a comparison of the field performance of sludge and clay hydraulic barriers. Two covers contain clay as the barrier material, one contains a paper mill primary sludge, and one contains a paper mill combined (primary and biological) sludge. One of the clay cells is designed to allow for a field verification study of the Hydrologic Evaluation of Landfill Performance (HELP) model.
Both sludge cells have produced smaller volumes of seepage and greater volumes of runoff than the clay cells to date. Calculated barrier hydraulic conductivities for the paper mill sludges are somewhat lower than those values calculated for the clay.