bluuebunny/crossref_metadata_2025 huggingface dataset:
Crystalline Silica Analysis: A Comparison of Calibration Materials and Recent Coal Mine Dust Size Distributions
Authors: Page SJ
Published: May 2009

Since 1982 standard calibration materials recommended for respirable crystalline silica analysis by the Mine Safety and Health Administration (MSHA) P7 Infrared Method and the National Institute for Occupational Safety and Health (NIOSH) X-ray Diffraction (XRD) Analytical Method 7500 have undergone minor changes in size distribution. However, a critical assumption has been made that the crystalline silica in ambient mine atmosphere respirable dust samples has also remained essentially unchanged in particle size distribution. The objective of this work, therefore, is to compare recent particle size distributions of underground coal mine dust and the silica component of these dusts with estimated aerodynamic particle size distributions of calibration standard materials MIN-U-SIL 5, Berkeley 5, and SRM 1878 used by two crystalline silica analysis techniques. This work provides resolution to a previously reported discrepancy involving the proper sample dilution for the particle sizing method used.

Dust impactor sampling data for various locations in 13 underground coal mines were collected between 1991 and 1998 and analyzed for the respirable mass median aerodynamic diameters. The data suggest that the MSHA P7 Method will underestimate the silica content of the sample by at most 8.5 % in the median size range of 0.9–3.6 µm and that it is unlikely one would obtain any significant error in the MSHA P7 Method analysis when the method uses Berkeley 5, MIN-U-SIL 5, or SRM 1878 as a calibration standard material.

The results suggest that the NIOSH Analytical Method 7500 would be more appropriate for a dust sample that is representative of the total (no cyclone classifier) rather than the respirable airborne dust, particularly since the mass fraction in the size range below 4 µm is usually a small percentage of the total airborne dust mass. However, the NIOSH Analytical Method 7500 is likely to underestimate the silica content of an airborne respirable dust sample by only 5–10%. The results of this study also suggest that any changes that may have occurred in the median respirable size of airborne coal mine dust are not significant enough to cause any appreciable error in the current methods used for respirable crystalline silica analysis.
An Evaluation of Aerosol- and Liquid-Generated Silica Samples for Proficiency Analytical Testing
Authors: Hayes T , Parish H , Key-Schwartz R , Popp D
Published: May 2009

SRI International has prepared dynamically generated silica samples since 1980 for the National Institute of Occupational Safety and Health (NIOSH) and the American Industrial Hygiene Association (AIHA) Proficiency Analytical Testing (PAT) programs. Aerosol-generated samples were developed in 1980 to more closely approximate real world samples and to improve intrabatch precision. Liquid-generated samples may provide tighter control limits, and this method has been reexamined as the generation procedure of choice. Sample preparation procedures have also been investigated to minimize analytical uncertainty and, hence, obtain a true evaluation of the sampling error. Samples were analyzed by SRI, NIOSH, and the Wisconsin Occupational Health Laboratory, using X-ray diffraction or Fourier transform infrared spectrometry (FTIR). Results were plotted and statistically evaluated, then compared to the existing PAT interlaboratory database.
Radiation-Induced Stress Relaxation of Welded Type 304 Stainless Steel Evaluated by Neutron Diffraction
Authors: Obata M , Root JH , Ishiyama Y , Nakata K , Sakamoto H , Anzai H , Asano K
Published: May 2009

The welded Type 304 stainless steel specimens were neutron-irradiated up to 2 × 1025 n/m2 (E > 1MeV) at 561K in the Japan Material Testing Reactor (JMTR). The residual stresses in the test specimens were measured by neutron diffraction, and the radiation-induced stress relaxation was evaluated from the change of stress distributions along the direction transverse to the weld bead. The magnitudes of σX (transverse to the weld) and σY (longitudinal to the weld) residual stresses decreased steadily with increasing neutron fluence. The irradiation dose dependence and the mechanism for the relaxation were examined using an equation derived from the irradiation creep equation. There was a steep stress relaxation, which might correspond to transient creep, at the early stage of neutron irradiation near the weld, and the different radiation-induced relaxation behaviors could be observed depending on the distance from the weld. The radiation-induced stress relaxation for welding-induced residual stress, which was generated under a three-dimensional restriction, indicated the tendency to be slower compared to the fundamental results for mechanically applied stress.
Flow Localization Processes in Austenitic Alloys
Authors: Wu X , Pan X , Li M , Stubbins JF
Published: May 2009

Austenitic alloys are widely used for structural component applications in high irradiation environments. In general, they are more resistant to embrittlement than other classes of structural alloys, particularly at ambient and intermediate temperatures. Nevertheless, this class of materials suffers from highly localized flow when irradiated to moderate dose (∼ 1 to 5 dpa) at temperatures between 150 and 400°C. The loss of ductility is normally exhibited by very low values of uniform elongation in tensile tests. The processes that lead to plastic instability are examined here for several face centered cubic materials and alloys. It is found that there is a critical stress level at which necking initiates. This critical stress level is not influenced by irradiation exposure. However, irradiation exposure, which increases material yield strength, does result in proportional reductions in uniform elongation. Most of the materials examined here exhibit a bilinear strain hardening behavior. This leads to direct correlation between the material yield strength and the uniform elongation.
Influence of Cold Rolling Threads Before or After Heat Treatment on High Strength Bolts for Different Fatigue Preload Conditions
Authors: Horn NJ , Stephens RI
Published: May 2009

SI grade 12.9 high strength steel bolts were used to investigate the fatigue behavior of bolt threads rolled before/after heat treatment using two different thread profiles and two different high preload values. Bolts were 3/8 UNRC-16 (coarse) and 3/8 UNRF-24 (fine) and preloads were taken as 75 and 90% of proof stress. Axial forces were applied through the nut. Axial and transverse residual stresses near the thread root were measured using X-ray diffraction. Most fracture surfaces contained crescent-shaped cracks and SEM evaluation indicated all fatigue crack growth regions contained multiple facets with no striations. Rolling after heat treatment caused little to no increase in fatigue resistance for the coarse threads. However, the fine threads finite fatigue life increased by factors of 2 to 5 and fatigue strengths based on Sa at 107 cycles increased by 40 and 50% for the 90 and 75% of proof stress preload, respectively. These are significant increases considering the very high preloads or R-ratios. The greater preload gave better fatigue resistance when based on the maximum stress, Smax, and lower fatigue resistance when based on the alternating stress, Sa Based on Smax, fatigue strengths at 107 cycles for 90% of preload were equivalent to or greater than the actual proof stress. Smax at 107 cycles for fine threads rolled after heat treatment with 75% of proof stress was also greater than the actual proof stress. The above results can be attributed to different thread root radii, thread region smoothness, original residual stress from rolling after heat treatment, and residual stress relaxation from the high preloads.
Suitable Adjuvant to Maximize Trifloxysulfuron Efficacy and Early Assessment of Herbicide Efficacy Using Chlorophyll Fluorescence
Authors: Singh S , Singh M
Published: May 2009

Trifloxysulfuron 2.5, 5, and 10 g ai/ha mixed with non-ionic (0.25% Induce and X-77), organosilicone (0.1 % Kinetic and Silwet L-77), and crop oil concentrate (1 % Agridex and Meth-N-Oil) adjuvants was evaluated for efficacy, surface tension (ST), contact angle (CA), and chlorophyll fluorescence responses in redroot pigweed, prickly sida, and barnyard grass. The lowest ST and CA were recorded with L-77 mixed with trifloxysulfuron. Among the six adjuvants, ST and CA were highest with Meth-N-Oil; however, these differences did not greatly influence herbicide efficacy. No trifloxysulfuron-adjuvant antagonism was found for any weed species. Differences in activities were observed at 2.5 g/ha trifloxysulfuron with different adjuvants; however, activities were comparable when data were averaged over species and rates. All the adjuvants increased trifloxysulfuron efficacy; some differences were observed among the weed species, but adjuvants were equal in improving trifloxysulfuron efficacy. Redroot pigweed was more sensitive to trifloxysulfuron compared to barnyardgrass and prickly sida was least. Chlorophyll fluorescence 1, 4, 7, and 14 days after treatment (DAT) was not greatly inhibited by trifloxysulfuron mixed with different adjuvants. Reduction in chlorophyll fluorescence was recorded 4 DAT in barnyard grass, but the reduction was not proportionate to the mortality and lacked uniformity among different treatments.
Surfactant-Enhanced Release of Permethrin from a Cellulosic Granular Carrier
Authors: Stern AJ
Published: May 2009

A study was conducted to determine whether the efficacy of pyrethroid insecticides, formulated with Biodac2 (an inert carrier granule derived from paper recycling waste) could be enhanced through the addition of surfactants. Thus, a series of formulations of permethrin on Biodac was prepared so that the effect of several nonionic surfactants on granule efficacy could be studied. To compare the efficacy of the formulations, the granules were tested on imported red fire ants, Solenopsis invicta, under laboratory conditions. Formulations with surfactant outperformed the control formulation (no surfactant) by a wide margin.
Development of a Fastener Structural Element Test for Certifying Navy Fastener Materials
Authors: Focht EM , L'Heureux BP , Roe C
Published: May 2009

New materials intended for use in critical U.S. Navy applications are evaluated by a Fracture Toughness Review Process (FTRP) for acceptability. In addition to developing data on the mechanical properties, fatigue life, and fracture toughness, the FTRP requires that a representative structural element test be performed to verify that the material can withstand plastic deformation at high loading rates in the presence of a detectable flaw. A Fastener Structural Element Test (FSET) has been developed to certify fastener materials such that the results of fracture mechanics testing on candidate alloys can be verified. The testing required the development of a suitable specimen that best represented a fastener, flaw seeding, and pre-cracking techniques, load and displacement measurement techniques suitable for high loading rates, and material performance acceptance criteria. The complete results of the testing on titanium alloy Ti-5AI-1Sn-1Zr-1V-0.8Mo (a.k.a. Ti-5111) and a Co-Ni-Cr-Mo-Al-Fe alloy will be presented along with the test methodology, data acquisition, and analysis details. The challenges encountered and areas that require further refinement will also be discussed.
Surface Roughness, Quasi-Static Fracture, and Cyclic Fatigue Effects on GFRP- and CFRP-Concrete Bonded Interfaces
Authors: Lawrence TO , Boyajian DM
Published: May 2009

The recently developed experimental fracture approach known as the Single Contoured-Cantilever Beam (SCCB) was used to characterize the interface bonds between concrete substrates and two varieties of FRP: glass and carbon (abbreviated GFRP and CFRP, respectively). Limited research has been performed concerning the FRP-concrete interface bond relative to three surface-roughness grades: low- (<10 μm), moderate- (≈ 10–50 μm), and high- (>50 μm), to establish the optimal formation for bonding. By use of the SCCB approach, Mode I critical strain energy release rate results are measured and quantified. Finally, considering that a majority of externally strengthened FRP concrete structures involves bridges and girders that are subjected to repeated (as opposed to static) loads, a preliminary study is conducted on cyclically fatigued FRP-concrete interfaces under varying load-ratio and frequency effects.
Detection of Crack Initiation by Observations of Free Surface Condition
Authors: Ichinose K , Yoshida S , Gomi K , Taniuchi K , Fukuda K , Ishii H
Published: May 2009

A simple method to detect crack initiation is presented. By polishing the surface of carbon steel structure properly and using the Lüders bands and orange peel as indicators for damage, it is possible to predict crack initiation with the naked eye. The initiation of the Lüders bands is the yellow light of the crack initiation, for instance, in the traffic signal, and orange peel is the red light. The relationship between the observed surface condition and the cyclic stress-strain characteristics is discussed.
Constraint CorrectedJ-R- Curve and Its Application to Fracture Assessment for X80 Pipelines
Authors: Zhu X-K , Leis BN
Published: May 2009

Single specimen J-R curve testing for X80 pipeline steel was conducted using single edge notched bend (SENB) and single edge notched tension (SENT) specimens with various crack lengths. Test data indicate that the J-R curves for this steel are strongly constraint dependent. To facilitate transferability of experimental J-R curves to those for actual cracked components, this paper develops a constraint corrected J-R curve for X80 steel. A modified J-Q theory that can consider the global bending stress influence is proposed so as to correctly quantify constraint effect on the crack-tip fields and the J-R curves. Results show that the modified J-Q solution can well match numerical crack-tip fields for bending specimens, with Q being a load-independent constraint parameter under large scale yielding. Based on the experimental data and numerical analysis, a constraint corrected J-R curve is formulated as a function of the parameter Q and crack extension Δa for X80 steel. A general procedure to predict J-R curves for actual cracked components is then outlined. Comparison indicates that the predicted J-R curves developed in this paper agree well with the experimental data for both SENB and SENT specimens. To demonstrate its application in failure assessment, the constraint corrected J-R curve for X80 steel is used to determine failure loads for a surface cracked pipeline. Reasonable agreement to available analytic solution is achieved.
Observations on Photo-Emission and the Process Zone of a Fatigue Crack
Authors: Patterson EA , Diaz FA , Yates JR
Published: May 2009

Cyclic loading of a solid material induces a cyclic temperature fluctuation. The thermal cycle is asynchronous with the loading cycle when the strains are elastic. This is commonly known as the thermoelastic effect. In differential thermography, a sensitive infrared camera is used to measure this temperature variation; typically of the order of a few tens of milliKelvin. Since the magnitude of the temperature variation is proportional to the dilational strain, values of the surface elastic stress can be derived. Recent advances in infrared camera technology and data processing algorithms have enabled values of effective stress intensity factor ranges and the location of fatigue cracks to be determined from temperature fluctuations around the crack tip on the specimen surface. Careful observation in the region near a crack tip reveals deviations from the asynchronous behavior of the photon signal relative to the load cycle. Phase shifts up to π/8 are commonly observed. The spatial distribution of these phase shifts exhibits characteristic features which are described and discussed. The features in this distribution appear to be associated with high elastic strain gradients, regions of plasticity and contact between the crack faces. Interpretation of the phase shift and its spatial distribution may lead to a better understanding of the mechanics of fatigue crack growth.
Temperature Dependence and Variability of Fracture Toughness in the Transition Regime for A508 Grade 4N Pressure Vessel Steel
Authors: Leax TR
Published: May 2009

A508 Grade 4N is a high nickel (3.4%) pressure vessel steel with a relatively high yield strength (585 MPa minimum for Class 1) and a relatively low transition temperature (47 J transition temperature of −29°C or below). Published fracture toughness data on this steel are nonexistent, and so they have not been included in prior assessments of the applicability of the Master Curve approach to pressure vessel steels. The purpose of this study is to compare the temperature dependence and data scatter for this steel with the behavior predicted by the Master Curve. The available database consists of approximately 800 fracture toughness tests on 51 material heats, some of which were given a temper embrittling heat treatment. As an additional basis of comparison, test data on A508 Grades 2 and 3, 1% nickel weld metal, and several high nickel (1.3–3.8%) steels (NiCrMo and NiCrMoV) were included in the assessment. Maximum likelihood techniques were used to fit the toughness data, and Monte Carlo methods were used to assess the observed distribution of Weibull slopes (related to the extent of variability). The results of this assessment show that the Master Curve provides a good description of the shape (temperature dependence) of the toughness curve for moderate and high transition temperatures. However, for heats with low transition temperatures below the range observed in other pressure vessel steels, the shape of the toughness curve deviates from the Master Curve. The lower the transition temperature, the larger the deviation from the Master Curve. Based on the test data, a model describing the behavior of A508 Grade 4N has been developed. This model also accurately describes the toughness behavior of the other pressure vessel steels included in this study. With respect to variability, the Weibull slope of A508 Grade 4N is consistent with the value of four prescribed by the Master Curve. However, the Weibull slope for the other pressure vessel steels included in this assessment is close to 3.4. This lower value of the Weibull slope, which indicates larger variability, is likely the result of material inhomogeneity.
Use of Miniaturized Compact Tension Specimens for Fracture Toughness Measurements in the Upper Shelf Regime
Authors: Lucon E , Scibetta M , Chaouadi R , van Walle E
Published: May 2009

In the nuclear field, the importance of direct fracture toughness measurements on reactor pressure vessel (RPV) materials has been nowadays widely recognized, as opposed to Charpy-based estimations. However, sample dimensions have to be kept small in order to optimize the use of available material (often in the form of previously broken Charpy specimens) or, in the case of new irradiations, make effective use of the limited space available inside irradiation facilities. One of the most appealing geometries for fracture toughness measurements is the miniature Compact Tension specimen, MC(T), which has the following dimensions: B = 4.15 mm, W = 8.3 mm, cross section 10 × 10 mm2. Four MC(T) specimens can be machined out of a broken half Charpy, and in the case of irradiation ten MC(T) samples occupy approximately the same volume as a full-size Charpy specimen. A comprehensive investigation is presented in this paper, aimed at assessing the applicability of MC(T) specimens to measure fracture toughness in fully ductile (upper shelf) conditions. In this study, 18 1TC(T) and 20 MC(T) specimens have been tested at different temperatures from three RPV steels and one low-alloy C-Mn steel. The results obtained clearly show that MC(T) samples exhibit lower fracture toughness properties, both in terms of initiation of ductile tearing (according to various test standards) and resistance to ductile crack propagation (J-R curve). The reduction of tearing resistance might be attributed to work hardening prevailing over loss of constraint in the uncracked ligament for a side-grooved specimen, or to the inadequacy of J-integral to represent ductile crack extension in very small specimens. Both arguments need to be verified with further investigations.
Analysis of Dynamic Fracture and Crack Arrest of an HSLA Steel in an SE(T) Specimen
Authors: Link RE
Published: May 2009

A single edge notch tension, SE(T), specimen was used to measure the dynamic fracture toughness and the crack arrest toughness of a tough HSLA steel in the ductile-brittle transition region. The SE(T) specimen was considerably smaller (W = 152 mm) than wide-plate specimens that have been typically used in other crack arrest tests. A thermal gradient was applied across the ligament of the specimen to facilitate a brittle crack initiation in the low temperature region of the specimen. The cleavage crack propagated into warmer and, consequently, tougher material which led to crack arrest. Transient, three-dimensional, finite element analyses of the tests were performed to determine the dynamic fracture and crack arrest toughness of the steel. The analyses employed both linear elastic and visco-plastic constitutive models. Dynamic strain measurements recorded during the run-arrest event were used to determine the crack tip position as a function of time during the event. This information was used as a boundary condition for the analysis. The measured strains were compared with strains predicted by the finite element analysis to validate the model. The dynamic response of the specimen, the effect of crack speed on the driving force, and the evolution of crack tip plasticity during the run-arrest event are discussed.
Remediation Technology for Boron and Fluoride Contaminated Sediments Using Green Plants
Authors: Asada M , Parkpian P , Horiuchi S
Published: May 2009

Phytoremediation is the direct application of green plants and their associated micro-organism to stabilize or absorb contaminants from soils, sludge, sediments, surface water, or groundwater. Boron and fluoride were listed to the soil standards a few years ago in Japan; however, few researches have been reported about phytoremediation on the above elements. In this paper, the authors report the experimental results of accumulation and tolerance ability of green plants focusing on the fluoride and boron contamination. In the pot laboratory tests, the growth rate of Chinese cabbage was not affected by low fluoride concentration (<15 mg/L) or low boron concentration (<5 mg/L). In the hydroponics tests, fluoride content in both stems+leaves and roots increased 3–10 times higher than control. Fluoride is easy to be concentrated in the roots. Boron content in both stems+leaves and roots increased 1.2–1.5 times higher than control. Boron is easy to be concentrated in the upper portion. Especially, Phytolacca Americana, Ambrosia trifida L., and Commelina communis can accumulate boron with higher efficiency. The boron content in soil was 480–550 mg/kg, and the boron content in these grasses was 2–3 times higher than that in soil. These results show they can accumulate boron and fluoride, and phytoremediation can be adopted for relatively lower contamination.
Optical Tests on the Slow Release of Biogenic Gas Bubbles in Sediment
Authors: Dyer M
Published: May 2009

The anaerobic decomposition of organic matter in marine or fresh water sediments can generate methane, carbon dioxide, hydrogen sulphide, and hydrogen as biogenic gases. In addition, innovative technologies are being used to remediate contaminated sediments and groundwater by releasing biogenic gases from the fermentation of carbon substrates as electron donors. Both scenarios can result in large discrete gas bubbles being present in sediment, which can affect aqueous permeability and mechanical strength. Furthermore the movement of gas bubbles can affect bioavailability as electron donors. In order to investigate bubble dispersion and movement in sediments, a series of novel optical experiments were carried out to observe the release and movement of discrete bubbles in artificial coarse-grained sediment. The results showed that buoyancy-induced movement depended on the clustering together of individual bubbles to achieve a critical depth of gas pocket to overcome the capillary force acting across the pore throat between sediment grains.
Development of Filtration System for Removal of Contaminated Suspended Solids in an Enclosed Sea Area
Authors: Fukue M , Minato T , Uehara K , Sato Y , Inoue T , Yamasaki S
Published: May 2009

The quality of seawater can be improved by removing suspended solids (SS) that may adsorb hazardous substances, such as heavy metals, polycyclic aromatic hydrocarbons, bacteria, etc. In this study, two types of filtration systems are developed in order to remove SS from sea, lake, and pond water. The first filtration system is a larger system for the rapid reduction of SS, and the other can be used for a slower removal of SS. The features of the smaller system are that solar panels were used as the power source and clogging of the filter can be prevented by a reverse water flow with an automatic control. Long-term in situ experiments showed that SS were almost completely removed by filters made of granular materials. Removal capacity was dependent primarily on both the sectional area of the filter and the relationship between the permeability of filter materials and the size of the SS. With treatment, good water quality was obtained in terms of SS, chemical oxygen demand and concentrations of nutrients.
A Combined Method: Precipitation and Capping, to Attenuate Eutrophication in Canadian Lakes
Authors: Galvez-Cloutier R , Leroueil S , Allier D , Locat J , Arsenault S
Published: May 2009

Eutrophication is a natural phenomenon, unfortunately amplified and accelerated by human activities. Phosphorus and nitrogen are the principal nutrients responsible for eutrophication. Their excess in the environment, of domestic and agricultural origins, represents an important toxicological risk for the users of water. These excessive nutrients cause algae overgrowth and excess oxygen consumption, which leads to anoxic waters, production of toxins (such as those produced by canobacteria), and the production of pollutant gases. Excess nutrients and dead biomass settles at the bottom of the lake together with other trace contaminants such as toxic metals that are trapped within bottom sediments. Seasonally, the sediments release nutrients and contaminants that need to be mitigated in order to prevent eutrophication and overall water contamination. In Quebec and in Canada several lakes suffer from this problem and solutions have been divided in preventive practices (better runoff controls, protection of shores, elimination of leaking domestic septic tanks) and rehabilitating practices (oxygenation of water, precipitation of nutrients, dredging of sediments or capping). This paper will present recent advances in the development of a combined rehabilitating technique: Precipitation of phosphorous and capping of contaminated sediments. The paper includes: a recent literature review; phosphorous precipitation experiments using alum under optimized parameters; capping design considerations and theory; as well as the results of an experimental simulation of capping using a composite liner calcite/sand.
Development of an In Situ Biodegradation Technology by Using Anaerobic Micro-Organisms for Sediment Contaminated with Dioxins
Authors: Hata T , Kurisu F , Yagi O , Mori H , Kuwano R , Kohashi H
Published: May 2009

In this paper, an in situ bioremediation method is proposed for dioxin contaminated sediments and its efficiency is assessed in laboratory tests including microbial analysis. The main outcomes of this research are (1) Proposal of an in situ bioremediation method using anaerobic micro-organisms monitored by molecular microbial techniques. (2) It was shown that the proposed method can reduce dioxin concentrations and can increase populations of the dehalogenating micro-organism (Dehalococcoides sp.). (3) It was further shown that the dioxin degradation processes can be monitored using polymerase chain reaction (PCR) denaturing gradient gel electrophoresis and real-time PCR. Microbial analysis using molecular techniques was useful for the monitoring and management of the sediment remediation process.
Monitoring Heavy Metal Transport in Aquifer Based on Electrical Property Measurements
Authors: Kim Y , Oh M , Bang S , Park J
Published: May 2009

Monitoring the movement of subsurface contamination using the electrical properties of soils has the economical merits of providing continuous and automated soil profiles. However, identification on the sensitivity of this property in reflecting both the presence and concentration of different contaminant types has been validated for soils under static conditions. For application, electrical properties of soils must be verified under an active state where contaminant migration by means of groundwater migration is considered. The objective of this study is to provide the groundwork required in applying the electrical properties of soil as a means of monitoring contaminant migration by performing column tests. Two parameters representing the electrical property of materials are examined in this study; the electrical resistivity and the dielectric constant. Measurements for these parameters are performed at a low frequency range where the spatial polarization takes place and increases the sensitivity of the electrical property against the presence of the contaminant. In order to detect the contaminant movement in the subsurface level, electrical measurements were performed during column tests for saturated sand and weathered granite soil. In addition, three different contaminants (aluminum, lead, and cadmium) were selected to groundwater contaminated by heavy metals. As a result, the relationships between the contaminant migration against the electrical resistivity, real, and imaginary parts of the dielectric constant were derived for different time intervals during the column tests.
Development of an Acoustical Method for Measuring the Transition Layer of Surficial Marine Sediments
Authors: Kimura M , Ishida K
Published: May 2009

A new acoustical method for measuring the physical properties for the transition layer of surficial marine sediments is proposed. In the proposed method, the frequency characteristics of the reflection coefficients for the acoustical normal incidence are utilized. The frequency characteristics of the reflection coefficients are influenced by the depth dependence of the porosity and the density. First, the relationships between the frequency characteristics of the reflection coefficients and the porosity variation with the depth are theoretically shown using Ocean Acoustics and Seismic Exploration Synthesis (OASES) (Biot-Stoll model). Then, the frequency characteristics of the reflection coefficients are measured in water tank and in situ. The measured results are compared with the calculated results using OASES (Biot-Stoll model). Finally, the usefulness of this method is demonstrated.
Effect of Dispersivity of Filling Material on Performance of Contaminant Barrier
Authors: Nishimura T , Shirato H , Hayashi M , Kato M
Published: May 2009

The performance of pollution barriers is discussed using solute soil dispersion parameters. Masa sandy loam and Toyoura sand, with dispersivities of 0.21 and 0.17 cm at saturation, respectively, were used as barrier material. 2.5 wt.% of the synthetic P-type zeolite was mixed with the soil to control the adsorption capacity of the barrier without changing soil structure. Soils were packed into an acrylic plastic column to form model barriers with different thicknesses. Adsorption capacity of the columns was between 6.1 and 7.5 mmolc per column. 42 mg·dm−3 Cd as nitrate solution was applied to the column under water saturated conditions, and effluent was collected at the bottom of the column. A relatively thin barrier, i.e., five times greater than the dispersivity, resulted in the detection of Cd with only 0.075 mmolc load of Cd, while a thicker barrier, 30 times greater than dispersivity, showed no leak of Cd with a 0.9 mmolc load of Cd added to the column.
Effects of Salt on the Sorption of Lead by Marine Clay in Column Tests
Authors: Ohtsubo M , Morishita T , Li L , Higashi T , Yamaoka S
Published: May 2009

In recent years incinerated municipal solid waste has been disposed of in landfill sites near the coastal area in Japan where the underlying marine clay deposits are expected to serve as a natural clay barrier. In this study, marine clay from Japan is examined for the effects of salt on sorption of lead using column leaching tests with deionized water, sea water, and bottom ash leachate spiked with 100 mg/L lead as permeants, and then selective sequential extraction (SSE) was employed to assess the retention mechanism of lead onto marine clay. Lead concentration in the effluent was less than 5 MG/L throughout the column leaching tests with the deionized water, whereas it exceeded Pb concentration in influent below one pore volume leaching for the sea water. Lead in pore water accumulated in the top layer of the column soil for the deionized water whereas it was distributed throughout the depth for the sea water and ash leachate. The SSE indicated that carbonate, exchangeable, and hydroxides phases are predominant for Pb retention.
Reactive Material Options for In Situ Capping
Authors: Olsta JT , Hornaday CJ , Darlington JW
Published: May 2009

Environmental dredging creates challenges in finding areas to construct confined disposal facilities and typically results in residual contamination. In situ capping (either in place of dredging or for capping residual contaminants) can be limited by concerns regarding navigation, uniform cap placement, biointrusion and geotechnical stability. A potential solution for many in situ capping concerns is the use of a reactive material cap. A reactive material cap could greatly reduce the thickness required for the cap compared to conventional sand caps. Various reactive materials (e.g., activated carbon, apatite, organoclay, zeolite, zero-valent iron) are used for removal of organics and metals in wastewater and groundwater treatment and may be applicable to in-situ capping. There are several ways that could be used for in-situ capping with reactive materials. A layer of reactive material could be placed in bulk using a clamshell or pumped through a tremie pipe. Another option is a reactive material filled geotextile mat. A reactive material mat would have several advantages over loose placement of reactive materials, including: (1) uniform and verifiable mass per area placement of reactive or adsorptive material; (2) ability to mix reactive or adsorptive materials in defined proportions; (3) geotextiles provide separation of the reactive material from the contaminated sediment and cover material; (4) geotextiles provide a barrier to biointrusion; (5) multiaxial strength of the geotextiles provides resistance to uplift and differential settlement; and (6) geosynthetic reinforcement provides stability on sloped areas. In the United States, a carbon-based geotextile mat was constructed and successfully deployed. A barge with a crane was used to deploy the material off shore. Other deployment methods have also been used for installing geosynthetics in waterways from shoreline and would be applicable to a reactive material mat.
Electrokinetic Remediation of Contaminated Dredged Sediment
Authors: Reddy KR , Ala PR
Published: May 2009

This paper investigates the feasibility of electrokinetic remediation of contaminated sediment at Indiana Harbor, Indiana. The sediment is a fine-grained material with high moisture content of 78 % and high organic content of 19 % and it is contaminated with a wide range of polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Four bench-scale electrokinetic experiments were conducted at 2.0 VDC/cm of constant voltage gradient using two surfactants (5 % Igepal CA-720 and 3 % Tween 80), a cosolvent (20 % n-butylamine), and a cyclodextrin (10 % HP-β-CD) as flushing solutions for the solubilization/desorption of PAHs. The mobility and removal of heavy metals was also investigated while flushing these solutions. The experimental results show that 20 % n-butylamine and 5 % Igepal 720 systems are effective for the partial solubilization of the PAHs in the sediments; however, both 3 % Tween 80 and 10 % HP-β-CD systems are found to be ineffective for desorption/solubilization of PAHs in the sediment. None of the selected flushing agents is found to be effective for the removal of heavy metals from the contaminated sediment. The low removal of PAHs and heavy metals is attributed to the high organic content and high acid buffering capacity of the sediment.
Groundwater Flow and Arsenic Contamination Analyses in Southern Bangladesh
Authors: Umeki T , Mano A , Ishibashi Y
Published: May 2009

Arsenic contamination had been found all over Bangladesh in 1993, however, the groundwater flow and the mechanism of arsenic contamination have not been made clear yet. Because the arsenic contamination spreads through the groundwater, it is important to understand the groundwater flow. We performed the field measurement from December 23rd to 25th, 2003 and from May 19th to 21st, 2004. Then we performed the numerical analyses of groundwater flow and arsenic transportation using modflow to grasp the field groundwater condition. As a result of the field measurement, the underground condition of our study area is reductive. Besides, using modflow, we could reproduce the groundwater flow properly and estimate a flux of groundwater drawn from wells, and then, predict the future contamination.
Evaluation of Diamond Detectors for Fast Neutron Fluence Measurements in WWER-1000 Surveillance Assemblies
Authors: Nikolaenko VA , Zaritsky SM , Bachuchin IV
Published: May 2009

The commonly used method of WWER-1000 surveillance dosimetry is based on the measurement of 54Mn absolute activity in the material of surveillance specimens. Special procedures are necessary for the determination of the spectral index for each specimen, which depends on surveillance assembly orientation in the reactor during the irradiation period, and for fluence extrapolation beyond several 54Mn half-life periods taking into account the detailed local power history in the core periphery. The application of the diamond detectors technique is proposed as an alternative method of fast neutron fluence determination. These detectors are located in the surveillance containers as irradiation temperature monitors. The diamond lattice extends under the influence of neutron irradiation, and it allows the fluence measurements after corresponding calibration. The calibration of diamond detectors was carried out using fluence data for 123 surveillance containers irradiated in different WWER-1000 reactors for different fluences. Some results of fluence measurements carried out by two methods are compared.
Promoted Metals Combustion at Ambient and Elevated Temperatures
Authors: Engel CD , Herald SD , Davis SE
Published: May 2009

Promoted combustion testing of materials, Test 17 of National Aeronautics and Space Administration Standard 6001 (NASA-STD-6001), has been used to assess metal propensity to burn in oxygenrich environments. An igniter at the bottom end of a rod promotes ignition, and if combustion is sustained, the burning progresses from the bottom to the top of the rod. The physical mechanisms are similar to those of the upward flame propagation test, Test 1 of NASA-STD-6001. The differences are in the normal environmental range of pressures, oxygen content, and sample geometry. Upward flammability testing of organic materials can exhibit a significant transitional region between no burning and complete quasi-steady burning. In this transitional region, the burn process exhibits a probabilistic nature. This transitional region has been identified for metals using the promoted combustion testing method at ambient initial temperatures. The work herein is focused on examining the transitional region and the quasi-steady burning region both at conventional ambient testing conditions and at elevated temperatures.
Fires in P-3 Aircraft Oxygen Systems
Authors: Stoltzfus J
Published: May 2009

Fires in three P-3 air craft oxygen systems have occurred: one in the Royal Australian Air Force in 1984 and two in the U.S. Navy in 1998 and 2003. All three fires started in the aluminum manifold and check valve (MCV) assembly and produced similar damages to the aircraft in which they occurred. This paper discusses a failure analysis conducted by the NASA Johnson Space Center White Sands Test Facility Oxygen Hazards and Testing Team on the 2003 U.S. Navy VP-62 fire. It was surmized that the fire started due to heat generated by an oxygen leak past a silicone check valve seal or possibly because of particle impact near the seat of one of the MCV assembly check valves. An additional analysis of fires in several check valve poppet seals from other aircraft is discussed. These burned poppet seals came from P-3 oxygen systems that had been serviced at the Naval Air Station in Jacksonville following standard fill procedures. It was concluded that these seal fires occurred due to the heat from compression heating, particle impact, or the heat generated by an oxygen leak past the silicone check valve seal. The fact that catastrophic fires did not occur in the case of each check valve seal fire was attributed to the protective nature of the aluminum oxide layer on the check valve poppets. To prevent future fires of this nature, the U.S. and Canadian fleets of P-3 aircraft have been retrofitted with MCV assemblies with an upgraded design and more burn-resistant materials.
Cleanliness of Bearing Steels and Fatigue Life of Rolling Contacts
Authors: Kerrigan A , Kuijpers JC , Gabelli A , Ioannides E
Published: May 2009

Established metallographic methods of determining the cleanliness of bearing steels with respect to micro-inclusions, such as ASTM E 45, are capable of differentiating poor quality melts from good quality melts. However, as steelmaker capabilities improve, with increasing numbers being able to consistently produce good quality melts, the established methods of cleanliness assessment are unable to differentiate between melts. These established methods, which give single figure ratings based on both the size and number of inclusions, are extremely difficult to use in predicting the performance of a bearing component under conditions of rolling contact fatigue. In this work, the method of Extreme Value Analysis (EVA) is used to characterize the inclusion population of five different steel melts of known and varying quality. A link between the EVA distribution and the measured bearing life, performed on material with a low reduction ratio, is also presented.
New Development in Through Hardened Bearing Steel Grades for Use in Contaminated Lubrication
Authors: Daguier P , Roesch O , Trojahn W
Published: May 2009

Bearing steel quality has been improved over the past decades by reducing the level and the size of nonmetallic inclusions. Therefore, fatigue lifetime of bearings is mainly governed by surface damage, such as debris denting due to foreign particles. Numerous studies have been performed to find out new steel grades or heat treatments to cope with such severe in-service conditions. Most of these studies argued that the level of retained austenite is the main parameter which governs fatigue lifetime. The present study relates to the effect of heat treatment and alloying elements on the fatigue lifetime of bearing steel in contaminated lubrication at room temperature. Several through hardened steel grades have been tested with different methodologies in order to investigate their behavior in case of: (1) Debris denting, (2) Resistance to Tempering, and (3) High loading conditions. An experimental procedure developed by FAG to simulate particle indentation on bearing has been used to study the behavior of each grade. On the other side, torsion tests at room and high temperature have been used to determine the evolution of fatigue limit. At last, flat washer testing at 4200 MPa is used to determine fatigue lifetime in high loading conditions. Results of fatigue tests are presented in this paper and analyzed in terms of tempering resistance and level of retained austenite.
Evaluation of Methodologies Used for Establishing Soil-Water Characteristic Curve
Authors: Shah PH , Sreedeep S , Singh DN
Published: May 2009

Different methodologies have been developed for establishing the soil-water characteristic curve, SWCC. These methodologies employ measurement of the soil suction with the help of different instrumentation techniques. However, as the instruments used for measuring soil suction work efficiently only for a certain range of suction, obtained SWCCs may not be representative. This calls for a systematic investigation, which would be of great help in determining the efficiency of each of these instruments for measuring the soil suction, and hence establishing the SWCC precisely. With this in view, the results obtained from a pressure membrane extractor (PME) and a dewpoint potentiameter (WP4), which are used quite frequently for the said purpose, were evaluated for the soils of entirely different characteristics. This technical note highlights the importance of utilization of the instruments in tandem for conducting multiple suction measurements in order to obtain a representative SWCC that covers the entire range of water content and corresponding suction.
The Effects of Implant Temperature on Lubricant Protein Precipitation and Polyethylene Wear in Joint Simulation Studies
Authors: Liao Y-S , Hanes M
Published: May 2009

Implant temperature increases as soon as a wear test starts. Frictional heating is the main reason for the temperature increase. Factors that affect the magnitude of the increase include the thermal conductivity of the implant materials, testing speed, and serum volume of the test chamber. High implant temperature can cause precipitation of soluble proteins in the serum lubricant. The protein precipitates can form a film at the wear interface and may affect laboratory wear evaluation of polyethylene liners. The effects of the implant temperature (of cobalt-chromium and zirconia femoral components) and the amount of protein precipitation from serum lubricant on the wear of UHMWPE liners has been demonstrated in a previous study using an external temperature control device. Furthermore, the nonlinear relationship of the implant temperature and the polyethylene wear has been discussed in another study, using moderately crosslinked UHMWPE liners tested against cobalt-chromium, zirconia, and alumina/zirconia composite femoral components at various temperatures. The results from both studies demonstrated that the temperature around the hip joint implants during a simulation can affect the wear rate of polyethylene. One guideline for minimizing the thermal effects on in vitro testing include circulation of coolant at an appropriate temperature to avoid overheating (due to nonstop running of the simulator) thus preventing excessive protein precipitation. This recommendation should help producing wear surfaces and wear debris that are more comparable to in vivo outcomes.
Joint Movement in Precast Concrete Panel Cladding
Authors: Karpati KK , Sereda PJ
Published: May 2009

Joint movements between precast concrete panels were measured on a high-rise building. The movements were correlated to air temperature changes and were statistically evaluated. An experimental coefficient of movement was calculated from the slope of the regression line and the dimension of the panels and was compared to the published linear coefficient of thermal expansion of concrete.