bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Investigation of a Small-Diameter, Cylindrical, Contaminated Ground-Water Plume Emanating from a Pyritic Uranium-Tailings Impoundment
Authors: Morin KA , Cherry JA 
Published: February 2009

As part of a larger study on the geochemical behavior and computer simulation of subsurface seepage from pyritic tailings impoundments, a detailed field study of such seepage has been conducted. At the field site, the tailings lie over a glaciofluvial sand aquifer. Near the southeastern corner of the tailings, acidic contaminated water (pH 4) seeps through the base of the tailings into the sand aquifer and flows laterally to the south as a distinct, roughly cylindrical plume. This plume contains up to 6000 ppm iron, up to 14 000 ppm sulfate (SO4), and elevated levels of other contaminants. The acidic seepage eventually encounters carbonate minerals in the aquifer, pH is then neutralized, and contaminants are attenuated through chemical precipitation, co-precipitation, and adsorption over a distance of several metres.
At the edge of the impoundment, the ground-water plume has a cross-sectional area of about 3 m2. Although the cross-sectional area suggests the plume is rather unimportant, the ground-water velocity is about 440 m/year, resulting in a lateral flux of more than 106 L of contaminant-laden water each year. The multilevel bundle piezometers installed to define this small-diameter plume are described and the installation techniques used to minimize disturbance of the plume are also addressed. Each bundle contains up to twelve individual piezometers with a vertical screen spacing of as small as 0.5 m. Horizontal distance between bundles is as small as 2.5 m.
The high total dissolved solids (TDS) water in the plume presents many problems for field and laboratory geochemical measurements. High partial pressures of carbon dioxide (CO2) in the water result in rapid degassing and subsequent pH fluctuation upon sampling. Because of the high degree of temperature-sensitive aqueous complexing in the water, temperature variations can affect pH measurements. Mixing of air with the water initiates iron oxidation. To acidify and stabilize a water sample, 30 mL of concentrated hydrochloric acid (HCl) must be added to each litre of sample, lowering the pH to about 1.5. Laboratory analysis of these samples often requires significant dilution, and the addition of neutral-pH and alkaline reagents to the sample causes ferric hydroxide precipitation and subsequent instrument clogging. Techniques are described to circumvent many of these problems and to collect reliable physical and chemical hydrogeologic data on this site.
Ground-Water Monitoring Techniques for Non-Point-Source Pollution Studies
Authors: Kimball CG 
Published: February 2009

The results of a ground-water monitoring project are based on samples collected from monitoring wells. The wells must be properly installed, constructed, and placed in accordance with project objectives and goals. Ground-water sampling must be conducted such that a representative sample is consistently obtained. Ground-water monitoring system design considerations include project goals and objectives, geology, hydrologic characteristics, chemical parameters to be monitored, and analysis and evaluation plans. To achieve a high-quality monitoring project with the capability of meeting project goals and objectives, the integration of a number of disciplines is necessary. Hydrogeologists, geologists, chemists, statisticians, engineers, and trained and experienced technical field personnel all provide valuable input.
A Comprehensive Monitoring and Evaluation project designed to detect changes in nitrogen and pesticide concentrations from agricultural activities is underway in eastern South Dakota. The geology and sampling situations encountered vary considerably throughout the project area. Experience gained through this project and techniques and methodologies applicable to ground-water monitoring are presented.
Ground-Water Contamination and Land Management in the Karst Area of Northeastern Iowa
Authors: Stan Mitchem P , Hallberg GR , Hoyer BE , Libra RD 
Published: February 2009

A statistical analysis of existing northeast Iowa water-quality data showed that systematic nonpoint contamination of ground-water quality was occurring in regional carbonate aquifers. Well-water quality generally improved with increased well depth and with natural geologic protection related to thickness of overlying bedrock or Quaternary aquitards. Nitrate levels were highest in areas where sinkholes were present; areas without sinkholes but with relatively thin protective cover had similar but somewhat lower levels of nitrate.
A detailed analysis of a single karst ground-water basin found the same systematic nitrate contamination along with low but persistent levels of herbicides. Agricultural practices were judged to be the sourceof the contaminants and infiltration was the principal mechanism. Ninety-five percent of the nitrate and 55 to 85% of the atrazine were delivered by infiltration and percolation.
Various state and Federal agencies, university researchers, local groups, and private organizations are cooperating in a seven-year project in the Big Spring basin to demonstrate and evaluate the effectiveness of best management practices on ground-water quality and on crop production. The project will provide research results to serve as a foundation for future policies and programs that agriculture must address relative to environmental problems.
Compositional Analysis by Thermogravimetry
Authors: Earnest CM 
Published: February 2009

Description
The Special Technical Publication is the result of an international symposium, which was held 16 and 17 March 1987 at Philadelphia, PA. This symposium was organized and sponsored by the ASTM Committee E37 on Thermal Measurements. The symposium as well as the special technical publication cover a broad spectrum of applications of thermogravimetry to the compositional analysis of materials. We are very pleased with the wide range of material types (polymers, rubber, cements, coal, oil shales, clays, and so forth) as well as the fact that authors from seven different countries participated in this symposium and subsequent publication.
Oral testosterone replacement in symptomatic late-onset hypogonadism: effects on rating scales and general safety in a randomized, placebo-controlled study
Authors: Legros Jean-Jacques , Meuleman Eric J H , Elbers Jolanda M H , Geurts T B Paul , Kaspers Marion J G H , Bouloux Pierre M G , _ _ 
Published: February 2009

ObjectiveTo investigate the effects of oral testosterone undecanoate (TU) on symptoms associated with late-onset hypogonadism (LOH).DesignMulticenter, randomized, double-blind, placebo-controlled.MethodsThe study was performed in 14 study centers in seven European countries. Men ≥50 years (n=322) with symptoms of hypogonadism and testosterone deficiency (calculated free testosterone <0.26 nmol/l) were randomized and treated for 12 months with placebo or oral TU 80, 160 or 240 mg/day. Primary outcome was the total score on the Aging Males' Symptoms (AMS) rating scale after six months of treatment.ResultsTreatment of mild-to-moderate LOH symptoms in subjects with borderline hypogonadism with oral TU resulted in an improved total AMS score at month 6, but differences between groups were not statistically significant. There was greater improvement in subjects <60 years when compared with subjects ≥60 years (P=0.001), but baseline testosterone level had no influence on treatment response. The AMS sexual symptoms domain improved with oral TU 160 mg/day at months 6 (P=0.008) and 12 (P=0.012) compared with placebo, but not with 80 and 240 mg/day. Treatment was well-tolerated and there were no between-group differences in adverse events or drop-out rates.ConclusionsIn one of the largest placebo-controlled studies of testosterone therapy in LOH, oral TU did not improve total AMS score in subjects with mild-to-moderate symptoms compared with placebo, except the sexual symptom sub-domain where a modest improvement was reported with oral TU 160 mg/day.
Genetic variation in exon 17 of INSR is associated with insulin resistance and hyperandrogenemia among lean Indian women with polycystic ovary syndrome
Authors: Mukherjee Srabani , Shaikh Nuzhat , Khavale Sushma , Shinde Gayatri , Meherji Pervin , Shah Nalini , Maitra Anurupa 
Published: February 2009

ObjectivePolycystic ovary syndrome (PCOS) is a multigenic disorder, and insulin resistance is one of its hallmark features. Polymorphisms in exon 17 of insulin receptor (INSR) gene are reported to be associated with PCOS. We investigated this association in Indian women and its putative relationship with PCOS associated traits, which has not been explored so far.MethodsIn this case control study, the polymorphisms were investigated by direct sequencing in 180 women with PCOS and 144 age matched controls. Clinical, anthropometric, biochemical, and hormonal parameters were also estimated.ResultsThe silent C/T polymorphism at His1058 in exon 17 of INSR was found to be present in our study population. The polymorphic genotype (CT+TT) was significantly associated with PCOS in lean women (χ2=8.493, df=1, P=0.004). It showed association with higher fasting insulin levels (P=0.02), homeostasis model assessment of insulin resistance (P=0.005), free androgen index (P=0.03), and lower quantitative insulin sensitivity check index (P=0.004) in lean PCOS women. No other novel or known polymorphism was identified in exon 17 in this cohort.ConclusionsThe study shows significant association of C/T polymorphism at His1058 of INSR with PCOS in the lean rather than obese Indian women. Its association with indices of insulin resistance and hyperandrogenemia is also seen in the same group. The findings strengthen the concept that pathogenesis of PCOS is different in lean and obese women.
Recent Achievement in the GaN Epitaxy on Silicon and Engineering Substrates
Authors: Arnaud Wilk , Lijadi Melania , Langer Robert , Bove Philippe , Thorpe James , Blanck Hervé , Hoel Virginie , Defrance Nicolas , DeJaeger Jean-Claude 
Published: February 2009

AbstractSince the middle of the 90's, GaN epitaxy techniques have been developed, using either MOCVD or MBE growth methods. A low cost approach is presented aiming at satisfying thermal issues encountered on conventional substrates such as SiC, Sapphire and more recently Silicon. Domain of application are being covered with their associated challenges: RF and High Power applications. Stress engineering is one of the key parameters.
Investigation of Amorphous InGaZnO Based TFT Interface Properties with Synchrotron Radiation Analysis
Authors: Joo Minho , Choi Jongkwon , Noh Seokhwan , Park Kyuho , Ihm Kyuwook , Kim Kijeong , Kang Taihee 
Published: February 2009

AbstractWe investigated the amorphous indium gallium zinc oxide (IGZO) based TFT interface properties using synchrotron radiation analysis. Near edge x-ray absorption fine structure shows the presence of N2 molecules between gate dielectric layer and active channel layer. The physical damage enhanced by the sputtering process was the origin of the device degradation evolving molecular state N2.
Influence of In-Situ Arsenic Doped Emitter Poly Process Conditions on RF-BiCMOS Device Parametrics
Authors: Egloff Richard , Paik Namwoong , Beckett Susan , Codi Daniel , Mase Jerry , Tomassi Wayne 
Published: February 2009

AbstractThis paper discusses the influence of deposition conditions on in-situ As doped amorphous silicon emitter films used in NPN RF bipolar transistors. In-situ As doped amorphous and/or polysilicon layers improve electrical performance in BiCMOS devices by reducing the number of process steps and eliminating issues associated with implanted polysilicon on high aspect ratio topographies (plug effect). This study was made using a vertical furnace configuration capable of 150 wafer loads. Because adsorbed AsH3 decomposition species tightly bind to the active surface sites and inhibit the deposition rate, the process recipe is complex. Predictable bipolar parametrics require control of the As diffusion profile within the base region after activation, so a thorough understanding of emitter film growth and dopant incorporation is necessary.We describe the relationship between process conditions and recipe variants on transistor gain (Hfe), base current (Ib), and emitter resistance (Re). SIMS and in-line sheet resistivity measurements were used to monitor dopant incorporation into the emitter. This data was found to be predictive not only of the Hfe for a population, but also as an indicator of potential “renegade” Hfe behavior.
Luminescence Properties in Er,O-codoped GaAs Light-Emitting Devices with Double Excitation Mechanism
Authors: Fujiwara Yasufumi , Fujii Kei , Fujita Ayafumi , Ota Yuji , Ito Yoshiaki , Kawasaki Takashi , Noguchi Kota , Tsuji Takahiro , Nishikawa Atsushi , Terai Yoshikazu 
Published: February 2009

AbstractWe fabricated a laser diode (LD) exhibiting a lasing from strained GaInAs quantum wells (QWs) embedded in Er,O-codoped GaAs (GaAs:Er,O) by organometallic vapor phase epitaxy (OMVPE). The lasing wavelength was designed to tune to the energy separation between the second excited states 4I11/2 and the ground state 4I15/2 of Er3+ ions. The threshold current for the lasing at room temperature was six times larger than that of a GaInAs QW-LD without Er doping, reflecting ultrafast carrier capture by an Er-related trap in GaAs:Er,O. The Er intensity revealed initially steep increase with injected current density in the region for spontaneous emission from the GaInAs QWs. In the stimulated QW emission region, the intensity continued to increase with the current density.
UV and Visible Luminescence of Pr3+ Doped Oxides: New Materials
Authors: Piccinelli Fabio , Speghini Adolfo , Ivanovskikh Konstantin , Meijerink Andries , Ronda Cees , Bettinelli Marco 
Published: February 2009

AbstractThe garnet Ca3Sc2Si3O12 (CSSO) and the silico-carnotite Ca3Y2Si3O12 (CYSO) and Ca3Lu2Si3O12 (CLSO) materials, both undoped and doped with Pr3+, have been synthesized by solid state reaction at high temperature. The luminescence spectroscopy and the excited state dynamics of the materials have been studied upon VUV and X-ray excitation using synchrotron radiation. All doped samples have shown efficient 5d-4f emission upon direct VUV excitation of 5d levels, but only CSSO:Pr3+ shows luminescence upon interband VUV or X-ray excitation. The VUV excited emission spectra of CYSO:Pr3+ and CLSO:Pr3+ show features attributed to emission from two distinct sites accommodating the Pr3+ dopant. The decay kinetics of the Pr3+ 5d-4f emission in CSSO:Pr3+ upon VUV excitation across the conduction band are characterized by decay times in the range 25-28 ns with no significant rise after the excitation pulse. They appear to be faster upon X-ray irradiation than for VUV excitation. Weak afterglow components are attributed to defect luminescence.
The Surface Electronic Band Structure CoS2(001)
Authors: Wu Ning , Losovyj Ya. B. , Manno Michael , Leighton Chris , Dowben Peter 
Published: February 2009

AbstractAngle-resolved photoemission was used to study the surface electronic band structure of ferromagnetic CoS2(below 120K) in high-quality single crystal samples. Strongly dispersing Co t2g bands are identified along the <100> k// direction. Fermi level crossings are identified along this Γ - X line (of the surface Brillouin zone) in higher resolution photoemission spectra, suggesting that the overall polarization may be controlled by the details of the band structure, particularly the surface band structure, rather than by exchange splitting on the Co atoms.
95Mo NMR Study of Crystallization in Model Nuclear Waste Glasses
Authors: Kroeker Scott , Farnan Ian , Schuller Sophie , Advocat Thierry 
Published: February 2009

Abstract95Mo magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy is surprisingly sensitive to the local environment of tetrahedral molybdate species. A series of compounds related to expected crystallization products in nuclear waste glasses are probed to calibrate their spectral characteristics. Glasses formed with fast and slow quenching show a glassy peak corresponding to tetrahedral molybdate species. With slow quenching, a prominent sharp peak is observed, representing crystallinity. In sodium-borosilicate glasses with 2.5 mol% MoO3, the sharp peak corresponds to pure crystalline sodium molybdate. Cesium-sodium and lithium-sodium borosilicate glasses with Mo show crystalline peaks as well, and suggest that NMR may potentially be used to characterize mixed-cation molydates and more complex phase assemblages. While precise quantification of Mo in different phases is likely to be time-consuming, reasonable estimates can be obtained routinely, making 95Mo MAS NMR a useful tool for investigating phase separation and crystallization in model nuclear waste materials.
Experimental Work Conducted on MgO Characterization and Hydration
Authors: Deng Haoran , Xiong Yongliang , Nemer Martin , Johnsen Shelly 
Published: February 2009

AbstractMagnesium oxide (MgO) is the only engineered barrier certified by the EPA for emplacement in the Waste Isolation Pilot Plant (WIPP), a U.S. Department of Energy repository for transuranic waste. MgO will reduce actinide solubilities by sequestering CO2 generated by the biodegradation of cellulosic, plastic, and rubber materials. Demonstration of the effectiveness of MgO is essential to meet the U.S Environmental Protection Agency's requirement for multiple natural and engineered barriers. In the past, a series of experiments was conducted at Sandia National Laboratories to verify the efficacy of Premier Chemicals LLC (Premier) MgO as a chemical-control agent in the WIPP. Since December 2004, Premier MgO is no longer available for emplacement in the WIPP. Martin Marietta Magnesia Specialties LLC is the new MgO supplier. MgO characterization, including chemical, mineralogic, and reactivity analysis, has been performed to address uncertainties concerning the amount of reactive constituents in Martin Marietta MgO. Characterization results of Premier MgO will be reported for comparison.
Particle size, solid-to-liquid ratio, and stir speed could affect the rate of carbonation of MgO slurries. Thus, it's reasonable to hypothesize that these factors will also affect the rate of hydration. Accelerated MgO hydration experiments were carried out at two or three levels for each of the above factors in deionized water at 70 °C. The Minitab statistical software package was used to design a fractional-factorial experimental matrix and analyze the test results. We also fitted the accelerated inundated hydration data to four different kinetic models and calculated the hydration rates. As a result of this study we have determined that different mechanisms may be important for different particle sizes, surface control for large particles and diffusion for small particles.
Investigation of Cathode Behavior of Model Thin Film SrTi1-xFexO3-&#948; Mixed Ionic-Electronic Conducting Electrodes
Authors: Tuller Harry L. , Jung WooChul , Haga Kengo 
Published: February 2009

AbstractThe defect structure, transport properties and band structure of the perovskite solid solution SrTi1-xFexO3-&#948; (STF) can be systematically controlled, over wide limits, by variation in the Fe fraction. In this paper, the authors review recent results which show that STF exhibits model mixed ionic-electronic conducting cathode behavior and extend the composition range investigated to include compositions from SrTiO3 rich values (x = 0.05) to SrFeO3-&#948; (x= 1). While the majority of the cathodes were prepared as dense films by pulsed layer deposition (PLD), selected compositions were also prepared by thermal inkjet printing. The cathodes were investigated by electrochemical impedance spectroscopy (EIS) as a function of electrode geometry, temperature and oxygen partial pressure. The electrode behavior was found to be controlled by surface exchange kinetics in almost all cases. Values for the surface exchange coefficient, k, were derived and found to be comparable in magnitude to those exhibited by other popular mixed ionic-electronic conductors such as (La,Sr)(Co,Fe)O3, thereby, confirming STF's suitability of as a model mixed conducting cathode material. Surprisingly, the magnitude of k was found to be only weakly dependent on the bulk electronic and ionic conductivities of STF which varied by many orders of magnitude (over nearly five orders of magnitude change in σel) over the x values examined in this study. The observed trends are discussed in relation to the known defect and transport properties of STF.
Sol-gel and PLD Preparation of Lanthanum Gallate-based Mixed Ionic-electronic Conducting Oxides
Authors: Golubko Natalia V , Kaleva Galina M , Roginskaya Yuliana E , Kabanov Sergey P , Avetisov Alexander A , Suchaneck Gunnar , Politova Ekaterina D 
Published: February 2009

AbstractIonic and mixed conducting oxides (La0.9Sr0.1)[(Ga1-xFex)0.8Mg0.2]O3-y (I) and (Sr1.8La0.2)(GaFe)O5.1 (II) with the perovskite and brownmillerite structures, respectively, have been prepared in forms of dense bulk ceramics and ceramic coatings by the sol-gel method. Thin films II have been grown by the pulsed laser deposition method on single crystal MgO (100) and Si (100), fused silica, and stainless steel substrates. The films grown under optimal process conditions were single-phase and homogeneous, with a high degree of preferential orientation. The structure and microstructure of the ceramic coatings have been studied by X-ray diffraction and scanning electron microscopy.
In situ Synchrotron X-ray Studies of Dense Thin-Film Strontium-Doped Lanthanum Manganite Solid Oxide Fuel Cell Cathodes
Authors: Chang Kee-Chul , Ingram Brian , Kavaipatti Balasubramaniam , Yildiz Bilge , Hennessy Daniel , Salvador Paul , Leyarovska Nadia , You Hoydoo 
Published: February 2009

AbstractUsing a model cathode-electrolyte system composed of epitaxial thin-films of La1-xSrxMnO3-δ (LSM) on single crystal yttria-stabilized zirconia (YSZ), we investigated changes in the cation concentration profile in the LSM during heating and under applied potential using grazing incidence x-rays. Pulsed laser deposition (PLD) was used to grow epitaxial LSM(011) on YSZ(111). At room temperature, we find that Sr segregates to form Sr enriched nanoparticles and upon heating the sample to 700°C, Sr is slowly reincorporated into the film. We also find different amounts of Sr segregation as the X-ray beam is moved across the sample. The variation in the amount of Sr segregation is greater on the sample that has been subject to 72 hours of applied potential, suggesting that the electrochemistry plays a role in the Sr segregation.
Doped Apatite Type Lanthanum Silicates: Structure and Property Characterization
Authors: Kharlamova Tamara , Pavlova Svetlana , Sadykov Vladislav A , Krieger Tamara , Batuev Lubsan , Muzykantov Vitalii , Lapina Olga , Khabibulin Dzalil , Chaikina Marina , Uvarov Nikolai , Pavlukhin Yurii , Petrov Sergei , Argirusis Christos 
Published: February 2009

AbstractStructural features and transport properties of Fe- and Al-doped apatite-type lanthanum silicates were studied with relation to a role of the [SiO4] substructure. XRD, TEM, Mössbauer, UV-Vis electron, IR, 29Si and 27Al NMR spectroscopy were used for structural studies; impedance spectroscopy and oxygen isotope heteroexchange were used for transport properties characterization.