Influence of Zeolite Coating on the Corrosion Resistance of AZ91D Magnesium Alloy.

PubMed

Banerjee, P Chakraborty; Woo, Ren Ping; Grayson, Sam Matthew; Majumder, Amrita; Raman, R K Singh

2014-08-22

The protective performance of zeolite coating on AZ91D magnesium alloy was evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 0.1 M sodium chloride solution (NaCl). Electrical equivalent circuit (EEC) was developed based upon hypothetical corrosion mechanisms and simulated to correspond to the experimental data. The morphology and the chemical nature of the coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Post corrosion morphologies of the zeolite coated and the uncoated AZ91D alloy were investigated using SEM. The corrosion resistance of the zeolite coated specimen was at least one order of magnitude higher than the uncoated specimen.

Wire Arc Additive Manufacturing of AZ31 Magnesium Alloy: Grain Refinement by Adjusting Pulse Frequency.

PubMed

Guo, Jing; Zhou, Yong; Liu, Changmeng; Wu, Qianru; Chen, Xianping; Lu, Jiping

2016-10-09

Wire arc additive manufacturing (WAAM) offers a potential approach to fabricate large-scale magnesium alloy components with low cost and high efficiency, although this topic is yet to be reported in literature. In this study, WAAM is preliminarily applied to fabricate AZ31 magnesium. Fully dense AZ31 magnesium alloy components are successfully obtained. Meanwhile, to refine grains and obtain good mechanical properties, the effects of pulse frequency (1, 2, 5, 10, 100, and 500 Hz) on the macrostructure, microstructure and tensile properties are investigated. The results indicate that pulse frequency can result in the change of weld pool oscillations and cooling rate. This further leads to the change of the grain size, grain shape, as well as the tensile properties. Meanwhile, due to the resonance of the weld pool at 5 Hz and 10 Hz, the samples have poor geometry accuracy but contain finer equiaxed grains (21 μm) and exhibit higher ultimate tensile strength (260 MPa) and yield strength (102 MPa), which are similar to those of the forged AZ31 alloy. Moreover, the elongation of all samples is above 23%.

Welding and Weldability of AZ31B by Gas Tungsten Arc and Laser Beam Welding Processes

NASA Astrophysics Data System (ADS)

Lathabai, S.; Barton, K. J.; Harris, D.; Lloyd, P. G.; Viano, D. M.; McLean, A.

Welding will play an important role in the fabrication of modular lightweight structures based on magnesium alloy die castings, extrusion profiles and wrought products. Minimisation of rejection rates during fabrication requires that satisfactory weldability be established for a particular combination of materials and welding procedures. In this paper, we present the results of a study to quantify the weldability of wrought alloy AZ31B by gas tungsten arc (GTA) and laser beam (LB) welding processes. The susceptibility to weld metal solidification cracking was evaluated using the Circular Patch weldability test. Operating windows of welding parameters for crack-free and porosity-free GTA and LB welding were identified, based on which welding procedures were developed for sheet and plate AZ31B. The microstructure and mechanical properties of welded test plates were assessed, leading to a better understanding of microstructurat development and structure-property relationships in GTA and LB weldments in AZ31B.

AZ-2000-IECW and StaMet Black Kapton Options for Solar Probe Plus MAG Sensor MLI Kevlar/Polyimide Shells

NASA Technical Reports Server (NTRS)

Choi, Michael K.

2017-01-01

AZ-2000-IECW white paint and StaMet black Kapton have been evaluated for the Kevlar/polyimide shells that enclose the Solar Probe Plus Magnetometer (MAG) sensors and multilayer insulation. Flight qualification testing on AZ-2000-IECW painted Kevlar/polyimide laminate was completed at Goddard Space Flight Center. This paint potentially meets all the requirements. However, it has no flight heritage. StaMet is hotter in the sun, and is specular. The results of the MAG thermal balance test show StaMet meets the thermal requirement and heater power budget. The mission prefers to fly StaMet after evaluating the risks of AZ-2000-IECW flaking and glint from StaMet to the Star Trackers.

Wide extragalactic (sub-)millimeter surveys with SCUBA and AzTEC

NASA Astrophysics Data System (ADS)

Aretxaga, I.; Hughes, D. H.; SHADES Collaboration; AzTEC Collaboration

2009-05-01

We summarize the present status of our knowledge of the millimeter galaxy population derived from extensive (sub-) millimeter extragalactic surveys like the SCUBA HAlf Degree Survey (SHADES), and the current status of the next generation of surveys traced with the AzTEC camera, that has, so far, surveyed more than 2 degrees at 1.1wavelengths.

Sensitivity of summer climate to anthropogenic land-cover change over the Greater Phoenix, AZ, region

USGS Publications Warehouse

Georgescu, M.; Miguez-Macho, G.; Steyaert, L.T.; Weaver, C.P.

2008-01-01

This work evaluates the first-order effect of land-use/land-cover change (LULCC) on the summer climate of one of the nation's most rapidly expanding metropolitan complexes, the Greater Phoenix, AZ, region. High-resolution-2-km grid spacing-Regional Atmospheric Modeling System (RAMS) simulations of three "wet" and three "dry" summers were carried out for two different land-cover reconstructions for the region: a circa 1992 representation based on satellite observations, and a hypothetical land-cover scenario where the anthropogenic landscape of irrigated agriculture and urban pixels was replaced with current semi-natural vegetation. Model output is evaluated with respect to observed air temperature, dew point, and precipitation. Our results suggest that development of extensive irrigated agriculture adjacent to the urban area has dampened any regional-mean warming due to urbanization. Consistent with previous observationally based work, LULCC produces a systematic increase in precipitation to the north and east of the city, though only under dry conditions. This is due to a change in background atmospheric stability resulting from the advection of both warmth from the urban core and moisture from the irrigated area. ?? 2008 Elsevier Ltd. All rights reserved.

View - Phoenix, AZ - Metropolitan Area - AZ

NASA Image and Video Library

1973-08-15

S73-35078 (July-Sept. 1973) --- A nearly vertical view of the Phoenix, Arizona metropolitan area is seen in this Skylab 3 (second manning) Earth Resources Experiments Package S190-B (five-inch Earth terrain camera) photograph taken from the Skylab space station in Earth orbit. Also in the picture are Scottsdale, Paradise Valley, Tempe, Mesa, Komatke, Salt River Indian Reservation and part of the Gila River Indian Reservation. Features which can be delineated from the photograph include: cultural patterns defined by commercial, industrial, agricultural and residential areas; transportation networks consisting of major corridors, primary, secondary and feeder streets; major urban developments in the area such as airports, Squaw Peak City Park, Turf Paradise Race Track and the State Fairgrounds. Phoenix is one of the 27 census cities of interest under study by the U.S. Geological Survey and is the center of the Arizona Regional Ecological Test Site. A large number of investigators will be using the Skylab data. This photo will be compared to earlier ones to document changes in the urban area with time. The landscape is well defined in terms of mountains, alluvial fans and river flood plains. Several different types of natural vegetation and irrigated crop lands can be mapped. Geological features are not well displayed but mining activities are readily identified. Photo credit: NASA

The Effect of Process Parameters and Tool Geometry on Thermal Field Development and Weld Formation in Friction Stir Welding of the Alloys AZ31 and AZ61

NASA Astrophysics Data System (ADS)

Zettler, R.; Blanco, A. C.; dos Santos, J. F.; Marya, S.

An increase in the use of magnesium (Mg) in the car manufacturing industry has raised questions concerning its weldability. Friction Stir Welding (FSW) has the advantage of achieving metallic bonding below that of the melting point of the base material thus avoiding many of the metallurgical problems associated with the solidification process. The present study presents the results of a development program carried out to investigate the response of Mg alloys AZ31 and AZ61 to different FSW tool geometries and process parameters. Temperature development across the weld zone was monitored and the produced welds have been subjected to microstructural analysis and mechanical testing. Defect free welds have been produced with optimised FSW-tool and parameters. The micro structure of the welded joint resulted in similar ductility and hardness levels as compared to that of the base material. The results also demonstrated that tool geometry plays a fundamental role in the response of the investigated alloys to the FSW process.

Loss of mechanical properties in vivo and bone-implant interface strength of AZ31B magnesium alloy screws with Si-containing coating.

PubMed

Tan, Lili; Wang, Qiang; Lin, Xiao; Wan, Peng; Zhang, Guangdao; Zhang, Qiang; Yang, Ke

2014-05-01

In this study the loss of mechanical properties and the interface strength of coated AZ31B magnesium alloy (a magnesium-aluminum alloy) screws with surrounding host tissues were investigated and compared with non-coated AZ31B, degradable polymer and biostable titanium alloy screws in a rabbit animal model after 1, 4, 12 and 21weeks of implantation. The interface strength was evaluated in terms of the extraction torque required to back out the screws. The loss of mechanical properties over time was indicated by one-point bending load loss of the screws after these were extracted at different times. AZ31B samples with a silicon-containing coating had a decreased degradation rate and improved biological properties. The extraction torque of Ti6Al4V, poly-l-lactide (PLLA) and coated AZ31B increased significantly from 1week to 4weeks post-implantation, indicating a rapid osteosynthesis process over 3weeks. The extraction torque of coated AZ31B increased with implantation time, and was higher than that of PLLA after 4weeks of implantation, equalling that of Ti6Al4V at 12weeks and was higher at 21weeks. The bending loads of non-coated AZ31B and PLLA screws degraded sharply after implantation, and that of coated AZ31B degraded more slowly. The biodegradation mechanism, the coating to control the degradation rate and the bioactivity of magnesium alloys influencing the mechanical properties loss over time and bone-implant interface strength are discussed in this study and it is concluded that a suitable degradation rate will result in an improvement in the mechanical performance of magnesium alloys, making them more suitable for clinical application. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Effect of Mucin and Bicarbonate Ion on Corrosion Behavior of AZ31 Magnesium Alloy for Airway Stents.

PubMed

Jang, Yongseok; Owuor, Daniel; Waterman, Jenora T; White, Leon; Collins, Boyce; Sankar, Jagannathan; Gilbert, Thomas W; Yun, Yeoheung

2014-08-15

The biodegradable ability of magnesium alloys is an attractive feature for tracheal stents since they can be absorbed by the body through gradual degradation after healing of the airway structure, which can reduce the risk of inflammation caused by long-term implantation and prevent the repetitive surgery for removal of existing stent. In this study, the effects of bicarbonate ion (HCO₃ - ) and mucin in Gamble's solution on the corrosion behavior of AZ31 magnesium alloy were investigated, using immersion and electrochemical tests to systematically identify the biodegradation kinetics of magnesium alloy under in vitro environment, mimicking the epithelial mucus surfaces in a trachea for development of biodegradable airway stents. Analysis of corrosion products after immersion test was performed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) was used to identify the effects of bicarbonate ions and mucin on the corrosion behavior of AZ31 magnesium alloys with the temporal change of corrosion resistance. The results show that the increase of the bicarbonate ions in Gamble's solution accelerates the dissolution of AZ31 magnesium alloy, while the addition of mucin retards the corrosion. The experimental data in this work is intended to be used as foundational knowledge to predict the corrosion behavior of AZ31 magnesium alloy in the airway environment while providing degradation information for future in vivo studies.

Influence of Zeolite Coating on the Corrosion Resistance of AZ91D Magnesium Alloy

PubMed Central

Banerjee, P. Chakraborty; Woo, Ren Ping; Grayson, Sam Matthew; Majumder, Amrita; Raman, R. K. Singh

2014-01-01

The protective performance of zeolite coating on AZ91D magnesium alloy was evaluated using potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) in 0.1 M sodium chloride solution (NaCl). Electrical equivalent circuit (EEC) was developed based upon hypothetical corrosion mechanisms and simulated to correspond to the experimental data. The morphology and the chemical nature of the coating were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis. Post corrosion morphologies of the zeolite coated and the uncoated AZ91D alloy were investigated using SEM. The corrosion resistance of the zeolite coated specimen was at least one order of magnitude higher than the uncoated specimen. PMID:28788178

Removal of hydrogen sulfide by sulfate-resistant Acidithiobacillus thiooxidans AZ11.

PubMed

Lee, Eun Young; Lee, Nae Yoon; Cho, Kyung-Suk; Ryu, Hee Wook

2006-04-01

Toxic H2S gas is an important industrial pollutant that is applied to biofiltration. Here, we examined the effects of factors such as inlet concentration and space velocity on the removal efficiency of a bacterial strain capable of tolerating high sulfate concentrations and low pH conditions. We examined three strains of Acidithiobacillus thiooxidans known to have sulfur-oxidizing activity, and identified strain AZ11 as having the highest tolerance for sulfate. A. thiooxidans AZ11 could grow at pH 0.2 in the presence of 74 g l(-1) sulfate, the final oxidation product of elemental sulfur, in the culture broth. Under these conditions, the specific sulfur oxidation rate was 2.9 g-S g-DCW (dry cell weight)(-1) d(-1). The maximum specific sulfur oxidation rate of A. thiooxidans AZ11 was 21.2 g-S g-DCW(-1) d(-1), which was observed in the presence of 4.2 g-SO4(2-) l(-1) and pH 1.5, in the culture medium. To test the effects of various factors on biofiltration by this strain, A. thiooxidans AZ11 was inoculated into a porous ceramic biofilter. First, a maximum inlet loading of 670 g-S m(-3) h(-1) was applied with a constant space velocity (SV) of 200 h(-1) (residence time, 18 s) and the inlet concentration of H2S was experimentally increased from 200 ppmv to 2200 ppmv. Under these conditions, less than 0.1 ppmv H2S was detected at the biofilter outlet. When the inlet H2S was maintained at a constant concentration of 200 ppmv and the SV was increased from 200 h(-1) to 400 h(-1) (residence time, 9 s), an H2S removal of 99.9% was obtained. However, H2S removal efficiencies decreased to 98% and 94% when the SV was set to 500 h(-1) (residence time, 7.2 s) and 600 h(-1) (residence time, 6 s), respectively. The critical elimination capacity guaranteeing 96% removal of the inlet H2S was determined to be 160 g-S m(-3) h(-1) at a space velocity of 600 h(-1). Collectively, these findings show for the first time that a sulfur oxidizing bacterium has a high sulfate tolerance and a high

Evaluating the improvement of corrosion residual strength by adding 1.0 wt.% yttrium into an AZ91D magnesium alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang Qiang; Liu Yaohui, E-mail: liuyaohui2005@yahoo.com; Fang Shijie

2010-06-15

The influence of yttrium on the corrosion residual strength of an AZ91D magnesium alloy was investigated detailedly. Scanning electron microscope was employed to analyze the microstructure and the fractography of the studied alloys. The microstructure of AZ91D magnesium alloy is remarkably refined due to the addition of yttrium. The electrochemical potentiodynamic polarization curve of the studied alloy was performed with a CHI 660b electrochemical station in the three-electrode system. The result reveals that yttrium significantly promotes the overall corrosion resistance of AZ91D magnesium alloy by suppressing the cathodic reaction in corrosion process. However, the nucleation and propagation of corrosion pitsmore » on the surface of the 1.0 wt.% Y modified AZ91D magnesium alloy indicate that pitting corrosion still emerges after the addition of yttrium. Furthermore, stress concentration caused by corrosion pits should be responsible for the drop of corrosion residual strength although the addition of yttrium remarkably weakens the effect of stress concentration at the tip of corrosion pits in loading process.« less

Evolution of twinning in extruded AZ31 alloy with bimodal grain structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garcés, G., E-mail: ggarces@cenim.csic.es

2017-04-15

Twinning in extruded AZ31 alloy with a bimodal grain structure is studied under compression along the extrusion direction. This study has combined in-situ measurements during the compression tests by Synchrotron Radiation Diffraction and Acoustic Emission techniques and the evaluation of the microstructure and texture in post-mortem compression samples deformed at different strains. The microstructure of the alloy is characterized by the coexistence of large areas of fine dynamic recrystallized grains and coarse non-recrystallized grains elongated along extrusion direction. Twinning occurs initially in large elongated grains before the macroscopic yield stress which is controlled by the twinning in equiaxed dynamically recrystallizedmore » grains. - Highlights: • The AZ31 extruded at low temperature exhibits a bimodal grains structure. • Twinning takes place before macroscopic yielding in coarse non-DRXed grains. • DRXed grains controls the beginning of plasticity in magnesium alloys with bimodal grain structure.« less

Radio Identification of Millimeter-Bright Galaxies Detected in the AzTEC/ASTE Blank Field Survey

NASA Astrophysics Data System (ADS)

Hatsukade, Bunyo; Kohno, Kotaro; White, Glenn; Matsuura, Shuji; Hanami, Hitoshi; Shirahata, Mai; Nakanishi, Kouichiro; Hughes, David; Tamura, Yoichi; Iono, Daisuke; Wilson, Grant; Yun, Min

2008-10-01

We propose a deep 1.4-GHz imaging of millimeter-bright sources in the AzTEC/ASTE 1.1-mm blank field survey of AKARI Deep Field-South. The AzTEC/ASTE uncovered 37 sources, which are possibly at z > 2. We have obtained multi-wavelength data in this field, but the large beam size of AzTEC/ASTE (30 arcsec) prevents us from identifying counterparts. The aim of this proposal is to identify radio counterparts with higher-angular resolution. This enables us (i) To identifying optical/IR counterparts. It enables optical spectroscopy to determine precise redshifts, allowing us to derive SFRs, luminosity functions, clustering properties, mass of dark matter halos, etc. (ii) To constrain luminosity evolutions of SMGs by comparing of 1.4-GHz number counts (and luminosity functions) with luminosity evolution models. (iii) To estimate photometric redshifts from 1.4-GHz and 1.1-mm data using the radio-FIR flux correlation. In case of non-detection, we can put deep lower limits (3 sigma limit of z > 3). These information lead to the study of evolutionary history of SMGs, their relationship with other galaxy populations, contribution to the cosmic star formation history and the infrared background.

Wire Arc Additive Manufacturing of AZ31 Magnesium Alloy: Grain Refinement by Adjusting Pulse Frequency

PubMed Central

Guo, Jing; Zhou, Yong; Liu, Changmeng; Wu, Qianru; Chen, Xianping; Lu, Jiping

2016-01-01

Wire arc additive manufacturing (WAAM) offers a potential approach to fabricate large-scale magnesium alloy components with low cost and high efficiency, although this topic is yet to be reported in literature. In this study, WAAM is preliminarily applied to fabricate AZ31 magnesium. Fully dense AZ31 magnesium alloy components are successfully obtained. Meanwhile, to refine grains and obtain good mechanical properties, the effects of pulse frequency (1, 2, 5, 10, 100, and 500 Hz) on the macrostructure, microstructure and tensile properties are investigated. The results indicate that pulse frequency can result in the change of weld pool oscillations and cooling rate. This further leads to the change of the grain size, grain shape, as well as the tensile properties. Meanwhile, due to the resonance of the weld pool at 5 Hz and 10 Hz, the samples have poor geometry accuracy but contain finer equiaxed grains (21 μm) and exhibit higher ultimate tensile strength (260 MPa) and yield strength (102 MPa), which are similar to those of the forged AZ31 alloy. Moreover, the elongation of all samples is above 23%. PMID:28773944

In vitro corrosion of pure magnesium and AZ91 alloy—the influence of thin electrolyte layer thickness

PubMed Central

Zeng, Rong-Chang; Qi, Wei-Chen; Zhang, Fen; Li, Shuo-Qi

2016-01-01

In vivo degradation predication faces a huge challenge via in vitro corrosion test due to the difficulty for mimicking the complicated microenvironment with various influencing factors. A thin electrolyte layer (TEL) cell for in vitro corrosion of pure magnesium and AZ91 alloy was presented to stimulate the in vivo corrosion in the micro-environment built by the interface of the implant and its neighboring tissue. The results demonstrated that the in vivo corrosion of pure Mg and the AZ91 alloy was suppressed under TEL condition. The AZ91 alloy was more sensitive than pure Mg to the inhibition of corrosion under a TEL thickness of less than 200 µm. The TEL thickness limited the distribution of current, and thus localized corrosion was more preferred to occur under TEL condition than in bulk solution. The TEL cell might be an appropriate approach to simulating the in vivo degradation of magnesium and its alloys. PMID:26816655

Lysobacter capsici AZ78 produces cyclo(L-Pro-L-Tyr), a 2,5-diketopiperazine with toxic activity against sporangia of Phytophthora infestans and Plasmopara viticola.

PubMed

Puopolo, G; Cimmino, A; Palmieri, M C; Giovannini, O; Evidente, A; Pertot, I

2014-10-01

To investigate low molecular weight compounds produced in vitro by Lysobacter capsici AZ78 and their toxic activity against sporangia of plant pathogenic oomycetes. Assays carried out in vitro showed that L. capsici AZ78 drastically inhibits the growth of plant pathogenic oomycetes. Accordingly, the preventive application of culture filtrates of L. capsici AZ78 on grapevine and tomato plants reduced the infections, respectively, caused by Plasmopara (Pl.) viticola and Phytophthora infestans. The subsequent chemical analysis of the culture filtrates of L. capsici AZ78 by spectroscopic (essentially 1D and 2D (1)H NMR and (13)C NMR and ESI MS spectra) and optical methods led to the identification of the 2,5-diketopiperazine cyclo(L-Pro-L-Tyr) that inhibited the development of P. infestans sporangia in vitro and on tomato leaves. Furthermore, a genomic region with high sequence identity with genes coding for a hybrid polyketide synthase and nonribosomal peptide synthetase was detected in L. capsici AZ78. Lysobacter capsici AZ78 produces cyclo(L-Pro-L-Tyr) in vitro that was effective in killing the sporangia of P. infestans and Pl. viticola in vitro. Moreover, this low molecular weight compound prevents the occurrence of late blight lesions when applied on tomato leaves. The application of L. capsici AZ78 cells or its own culture filtrates effectively controls both P. infestans and Pl. viticola. Cyclo(L-Pro-L-Tyr) produced by L. capsici AZ78 is toxic against sporangia of both these oomycetes. These data enforce the potential in the use of Lysobacter members for the control of plant pathogenic oomycetes and provide the basis for the development of new low-impact fungicides based on cyclo(L-Pro-L-Tyr). © 2014 The Society for Applied Microbiology.

THE REDSHIFT AND NATURE OF AzTEC/COSMOS 1: A STARBURST GALAXY AT z = 4.6

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smolcic, V.; Capak, P.; Blain, A. W.

2011-04-20

Based on broadband/narrowband photometry and Keck DEIMOS spectroscopy, we report a redshift of z = 4.64{sup +0.06}{sub -0.08} for AzTEC/COSMOS 1, the brightest submillimeter galaxy (SMG) in the AzTEC/COSMOS field. In addition to the COSMOS-survey X-ray to radio data, we report observations of the source with Herschel/PACS (100, 160 {mu}m), CSO/SHARC II (350 {mu}m), and CARMA and PdBI (3 mm). We do not detect CO(5 {yields} 4) line emission in the covered redshift ranges, 4.56-4.76 (PdBI/CARMA) and 4.94-5.02 (CARMA). If the line is within this bandwidth, this sets 3{sigma} upper limits on the gas mass to {approx}<8 x 10{sup 9}more » M{sub sun} and {approx}<5 x 10{sup 10} M{sub sun}, respectively (assuming similar conditions as observed in z {approx} 2 SMGs). This could be explained by a low CO-excitation in the source. Our analysis of the UV-IR spectral energy distribution of AzTEC 1 shows that it is an extremely young ({approx}<50 Myr), massive (M{sub *} {approx} 10{sup 11} M{sub sun}), but compact ({approx}<2 kpc) galaxy, forming stars at a rate of {approx}1300 M{sub sun} yr{sup -1}. Our results imply that AzTEC 1 is forming stars in a 'gravitationally bound' regime in which gravity prohibits the formation of a superwind, leading to matter accumulation within the galaxy and further generations of star formation.« less

N terminus of Swr1 binds to histone H2AZ and provides a platform for subunit assembly in the chromatin remodeling complex.

PubMed

Wu, Wei-Hua; Wu, Chwen-Huey; Ladurner, Andreas; Mizuguchi, Gaku; Wei, Debbie; Xiao, Hua; Luk, Ed; Ranjan, Anand; Wu, Carl

2009-03-06

Variant histone H2AZ-containing nucleosomes are involved in the regulation of gene expression. In Saccharomyces cerevisiae, chromatin deposition of histone H2AZ is mediated by the fourteen-subunit SWR1 complex, which catalyzes ATP-dependent exchange of nucleosomal histone H2A for H2AZ. Previous work defined the role of seven SWR1 subunits (Swr1 ATPase, Swc2, Swc3, Arp6, Swc5, Yaf9, and Swc6) in maintaining complex integrity and H2AZ histone replacement activity. Here we examined the function of three additional SWR1 subunits, bromodomain containing Bdf1, actin-related protein Arp4 and Swc7, by analyzing affinity-purified mutant SWR1 complexes. We observed that depletion of Arp4 (arp4-td) substantially impaired the association of Bdf1, Yaf9, and Swc4. In contrast, loss of either Bdf1 or Swc7 had minimal effects on overall complex integrity. Furthermore, the basic H2AZ histone replacement activity of SWR1 in vitro required Arp4, but not Bdf1 or Swc7. Thus, three out of fourteen SWR1 subunits, Bdf1, Swc7, and previously noted Swc3, appear to have roles auxiliary to the basic histone replacement activity. The N-terminal region of the Swr1 ATPase subunit is necessary and sufficient to direct association of Bdf1 and Swc7, as well as Arp4, Act1, Yaf9 and Swc4. This same region contains an additional H2AZ-H2B specific binding site, distinct from the previously identified Swc2 subunit. These findings suggest that one SWR1 enzyme might be capable of binding two H2AZ-H2B dimers, and provide further insight on the hierarchy and interdependency of molecular interactions within the SWR1 complex.

75 FR 49526 - Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

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Geologie study off gravels of the Agua Fria River, Phoenix, AZ

USGS Publications Warehouse

Langer, W.H.; Dewitt, E.; Adams, D.T.; O'Briens, T.

2010-01-01

The annual consumption of sand and gravel aggregate in 2006 in the Phoenix, AZ metropolitan area was about 76 Mt (84 million st) (USGS, 2009), or about 18 t (20 st) per capita. Quaternary alluvial deposits in the modern stream channel of the Agua Fria River west of Phoenix are mined and processed to provide some of this aggregate to the greater Phoenix area. The Agua Fria drainage basin (Fig. 1) is characterized by rugged mountains with high elevations and steep stream gradients in the north, and by broad alluvial filled basins separated by elongated faultblock mountain ranges in the south. The Agua Fria River, the basin’s main drainage, flows south from Prescott, AZ and west of Phoenix to the Gila River. The Waddel Dam impounds Lake Pleasant and greatly limits the flow of the Agua Fria River south of the lake. The southern portion of the watershed, south of Lake Pleasant, opens out into a broad valley where the river flows through urban and agricultural lands to its confluence with the Gila River, a tributary of the Colorado River.

Microstructure Characterization of Weakly Textured and Fine Grained AZ61 Sheet

NASA Astrophysics Data System (ADS)

Berman, T. D.; Donlon, W.; Hung, C. K.; Milligan, P.; Decker, R.; Pollock, T. M.; Jones, J. W.

Formability in magnesium alloy sheet is strongly limited by a strong basal texture in the as-rolled material, which is difficulty to remove by thermal processing. We introduce a new process to the control of texture by combining Thixomolding and Thermomechanical Processing (TTMP). Plates of AZ61L with a divorced β-Mg17Al12 eutectic are produced by Thixomolding, resulting in a non-textured, fine grained (2.8 µm) precursor. Sheet produced from the plate by single pass warm-rolling exhibits a weaker texture, and more isotropic tensile deformation than generally observed in AZ-series alloy sheet. Recrystallization annealing produces a further reduction in texture and average grain size (2.3 µm) and results in nearly isotropic room temperature deformation, a yield strength of 220 MPa, and an elongation of 23%. Particle stimulated nucleation of new grains by the β-phase during both dynamic and static recrystallization, is critical for achieving the low levels of texture. The influence of β-phase distribution in microstructure development is discussed.

Effect of Mucin and Bicarbonate Ion on Corrosion Behavior of AZ31 Magnesium Alloy for Airway Stents

PubMed Central

Jang, Yongseok; Owuor, Daniel; Waterman, Jenora T.; White, Leon; Collins, Boyce; Sankar, Jagannathan; Gilbert, Thomas W.; Yun, Yeoheung

2014-01-01

The biodegradable ability of magnesium alloys is an attractive feature for tracheal stents since they can be absorbed by the body through gradual degradation after healing of the airway structure, which can reduce the risk of inflammation caused by long-term implantation and prevent the repetitive surgery for removal of existing stent. In this study, the effects of bicarbonate ion (HCO3−) and mucin in Gamble’s solution on the corrosion behavior of AZ31 magnesium alloy were investigated, using immersion and electrochemical tests to systematically identify the biodegradation kinetics of magnesium alloy under in vitro environment, mimicking the epithelial mucus surfaces in a trachea for development of biodegradable airway stents. Analysis of corrosion products after immersion test was performed using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Electrochemical impedance spectroscopy (EIS) was used to identify the effects of bicarbonate ions and mucin on the corrosion behavior of AZ31 magnesium alloys with the temporal change of corrosion resistance. The results show that the increase of the bicarbonate ions in Gamble’s solution accelerates the dissolution of AZ31 magnesium alloy, while the addition of mucin retards the corrosion. The experimental data in this work is intended to be used as foundational knowledge to predict the corrosion behavior of AZ31 magnesium alloy in the airway environment while providing degradation information for future in vivo studies. PMID:28788166

A weight of evidence approach for assessing remediation of ...

EPA Pesticide Factsheets

The Ottawa River lies in extreme northwest Ohio, flowing into Lake Erie’s western basin at the city of Toledo. The Ottawa River is a component of the Maumee River Area of Concern (AOC) as defined by the International Joint Commission. In 2009-2010 a sediment remediation project took place in the lower 8.8 miles of the river where urban and industrial activities impacted the river as a beneficial resource. Sediment was removed at designated locations based on a surface weighted average concentration model where PCB and PAH levels exceeded targeted levels. This presentation will focus on three biological tools: assessing response of tissue concentrations of PCBs and PAHs, DNA damage in Brown Bullhead and macroinvertebrate biotic condition as measured by Ohio EPA Lacustrine Index of Community Integrity (LICI). From 2009-2013 and again in 2015, pre- and post-remedy sampling of fishes representative of different trophic levels was conducted via electroshocking and fyke net sampling. The study area was divided into 3 river reaches (reaches 2, 3, & 4 numbered from down- to upstream). Fish were collected by electro-shocking or fyke netting across an entire reach where Largemouth Bass, Brown Bullhead, White Sucker, Pumpkinseed, Gizzard Shad, Bluntnose Minnow and Emerald Shiner. Blood samples were collected from 10 Brown Bullheads from each reach and processed in the field and laboratory using Comet Assay methods.Two different configurations of multiplate samplers (Hest

Canyon Day Sand and Gravel Wash Process Plant: Draft NPDES Permit AZ0024511

EPA Pesticide Factsheets

EPA is issuing a notice of proposed action under the Clean Water Act to issue NPDES Permit No.permit renewal (No. AZ0024511) to White Mountain Apache Tribe Canyon Day Sand and Gravel Wash Process Plant, Greer, Arizona.

75 FR 11939 - DNS Electronics, Chandler, AZ; Notice of Termination of Investigation

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-12

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-70,654] DNS Electronics, Chandler, AZ; Notice of Termination of Investigation Pursuant to Section 223 of the Trade Act of 1974, as... on behalf of workers of DNS Electronics, Chandler, Arizona. The petitioning group of workers is...

[11C]AZ10419096 - a full antagonist PET radioligand for imaging brain 5-HT1B receptors.

PubMed

Lindberg, Anton; Nag, Sangram; Schou, Magnus; Takano, Akihiro; Matsumoto, Junya; Amini, Nahid; Elmore, Charles S; Farde, Lars; Pike, Victor W; Halldin, Christer

2017-11-01

The serotonergic system is widely present in all regions of the central nervous system (CNS) and plays a key modulatory role in many of its functions. Positron emission tomography (PET) is used to study several serotonin receptors in CNS in vivo. The G-protein coupled receptor 5-HT 1B is mostly present in the occipital cortex and in midbrain and is linked to several psychiatric disorders. There is evidence that agonist PET radioligands for neuroreceptors are more sensitive to endogenous neurotransmitters than antagonists. Our previously developed 5-HT 1B receptor PET radioligand, [ 11 C]AZ10419369, is now considered a partial agonist. In this work we are aiming to develop a full antagonist PET radioligand for imaging brain 5-HT 1B receptors, and evaluate its sensitivity to increased endogenous serotonin concentration. [ 11 C]AZ10419096 was synthesized by rapid methylation of the prepared corresponding N-desmethyl precursor with [ 11 C]methyl triflate. Five PET measurements were performed in cynomolgus monkeys, consisting of two at baseline, one after treatment of a monkey with a 5-HT 1B antagonist, AR-A000002, and two in which fenfluramine was administered during scanning to induce endogenous serotonin release. [ 11 C]AZ10419096 was synthesized in high yield and purity within 30 min, including purification, formulation and sterile filtration. The baseline PET measurements demonstrated [ 11 C]AZ10419096 to have favorable radioligand characteristics, including high specific binding in brain regions that have high 5-HT 1B density, such as occipital cortex and globus pallidus, as well as subsequent rapid elimination from brain and a minor abundance of lipophilic radiometabolites in plasma. AR-A00002 completely blocked radioligand receptor-specific binding. Fenfluramine produced a distinct displacement of radioligand consistent with an expected increase of synaptic endogenous serotonin concentration. [ 11 C]AZ10419096, a full 5-HT 1B antagonist PET radioligand

Flow behaviour of magnesium alloy AZ31B processed by equal-channel angular pressing

NASA Astrophysics Data System (ADS)

Arun, M. S.; Chakkingal, U.

2014-08-01

Magnesium alloys are characterised by their low density, high specific strength and stiffness. But, the potential application of Mg is limited by its low room-temperature ductility & formability. Formability can be improved by developing an ultrafine grained (UFG) structure. Equal channel angular pressing (ECAP) is a well known process that can be used to develop an ultrafine grained microstructure. The aim of this study was to investigate the flow behaviour of AZ31B magnesium alloy after ECAP. The specimen was subjected to three passes of ECAP with a die angle of 120° using processing route Bc. The processing temperature was 523 K for the first pass and 423 K for the subsequent two passes. The microstructure characterisation was done. Compression tests of ECAPed and annealed specimens were carried out at strain rates of 0.01 - 1s-1 and deformation temperatures of 200 - 300°C using computer servo-controlled Gleeble-3800 system. The value of activation energy Q and the empirical materials constants of A and n were determined. The equations relating flow stress and Zener-Hollomon parameter were proposed. In the case annealed AZ31, the activation energy was determined to be 154 kJ/mol, which was slightly higher than the activation energy of 144 kJ/mol for ECAPed AZ31.

Cerium Addition Improved the Dry Sliding Wear Resistance of Surface Welding AZ91 Alloy

PubMed Central

Zhao, Zhihao; Zhu, Qingfeng; Wang, Gaosong; Tao, Kai

2018-01-01

In this study, the effects of cerium (Ce) addition on the friction and wear properties of surface welding AZ91 magnesium alloys were evaluated by pin-on-disk dry sliding friction and wear tests at normal temperature. The results show that both the friction coefficient and wear rate of surfacing magnesium alloys decreased with the decrease in load and increase in sliding speed. The surfacing AZ91 alloy with 1.5% Ce had the lowest friction coefficient and wear rate. The alloy without Ce had the worst wear resistance, mainly because it contained a lot of irregularly shaped and coarse β-Mg17Al12 phases. During friction, the β phase readily caused stress concentration and thus formed cracks at the interface between β phase and α-Mg matrix. The addition of Ce reduced the size and amount of Mg17Al12, while generating Al4Ce phase with a higher thermal stability. The Al-Ce phase could hinder the grain-boundary sliding and migration and reduced the degree of plastic deformation of subsurface metal. Scanning electron microscopy observation showed that the surfacing AZ91 alloy with 1.5% Ce had a total of four types of wear mechanism: abrasion, oxidation, and severe plastic deformation were the primary mechanisms; delamination was the secondary mechanism. PMID:29415492

Find a Dermatologic Surgeon

MedlinePlus

... class="button-learn-more"> State AL AK AZ AR CA CO CT DE DC FL GA HI ... 250 Miles Locality City: State: AB AK AL AR AZ BC CA CO CT DC DE FL ... clicking on the procedure name. State AK AL AR AZ CA CO CT DC DE FL GA ...

241-AZ-101 Waste Tank Color Video Camera System Shop Acceptance Test Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

WERRY, S.M.

2000-03-23

This report includes shop acceptance test results. The test was performed prior to installation at tank AZ-101. Both the camera system and camera purge system were originally sought and procured as a part of initial waste retrieval project W-151.

The Corrosion Protection of Magnesium Alloy AZ31B

NASA Technical Reports Server (NTRS)

Danford, M. D.; Mendrek, M. J.; Mitchell, M. L.; Torres, P. D.

1997-01-01

Corrosion rates for bare and coated Magnesium alloy AZ31B have been measured. Two coatings, Dow-23(Trademark) and Tagnite(Trademark), have been tested by electrochemical methods and their effectiveness determined. Electrochemical methods employed were the scanning reference electrode technique (SRET), the polarization resistance technique (PR) and the electrochemical impedance spectroscopy technique (EIS). In addition, general corrosion and stress corrosion methods were employed to examine the effectiveness of the above coatings in 90 percent humidity. Results from these studies are presented.

Physical Properties of AZ91D Measured Using the Draining Crucible Method: Effect of SF6

NASA Astrophysics Data System (ADS)

Roach, Steven J.; Henein, Hani

2012-03-01

The draining crucible (DC) technique was used for measurements on AZ91D under Ar and SF6. The DC technique is a new method developed to simultaneously measure the physical properties of fluids, the density, surface tension, and viscosity. Based on the relationship between the height of a metal in a crucible and the outgoing flow rate, a multi-variable regression is used to calculate the values of these fluid properties. Experiments performed with AZ91D at temperatures from 923 K to 1173 K indicate that under argon, the surface tension (N · m-1) and density (kg · m-3) are [0.63 - 2.13 × 10-4 ( T - T L)] and [1656 - 0.158 ( T - T L)], respectively. The viscosity (Pa · s) has been determined to be [1.455 × 10-3 - 1.209 × 10-5 ( T - T L)] over the temperature range from 921 K to 967 K superheat. Above 967 K, the viscosity of the alloy under argon seems to be constant at (2.66 × 10-4 ± 8.67 × 10-5) Pa · s. SF6 reduces the surface tension of AZ91D.

Dry Sliding Wear Charactristics of Aluminum 6061-T6, Magnesium AZ31 and Rock Dust Composite

NASA Astrophysics Data System (ADS)

Balachandar, R.; Balasundaram, R.; Rajkumar, G.

2018-02-01

In recent years, the use of aluminum composite is gaining popularity in a wide range of applications like automobiles, aerospace and constructions (both interior & exterior) panels etc., due to its high strength, low density characteristics. Various reinforcing materials are used with aluminum 6061-T6 in order to have better mechanical properties. The addition of 0.3% of magnesium AZ31 will increase the ultimate tensile strength by 25 %. The reinforcement of rock dust will decrease the density. Hence, in order to have an advantages of magnesium AZ31 and rock dust, in this work, these two constitutes are varied from 1% to 2% on the base material of Al6061-T6 in stir casting. To evaluate the wear characteristics, Pin on disc is used in these composites. The input parameters are speed, time & load. The output response is wear. To minimize the number of experiments, L9 orthogonal array is used. The test results showed that a composite of 97% of Al (6061-T6), 1% Mg (AZ31) & 2 % of rock dust produced less wear. To find the best value of operating parameter for each sample, ANN-GA is used.

Synthesis and properties of hydroxyapatite-containing coating on AZ31 magnesium alloy by micro-arc oxidation

NASA Astrophysics Data System (ADS)

Tang, Hui; Han, Yu; Wu, Tao; Tao, Wei; Jian, Xian; Wu, Yunfeng; Xu, Fangjun

2017-04-01

In this study, hydroxyapatite-containing coatings were prepared by microarc oxidation on AZ31 magnesium alloy surface to improve its biodegradation performance. Five applied voltages were chosen to prepare the MAO coatings. The results demonstrate that the number of micropores in the films increases but their dimensions decrease after higher voltage is applied. As the surface roughness of the MAO coatings increases with the applied voltage, the wettability of the coatings improves continuously. The MAO coatings were mainly composed of magnesium oxide (MgO) and hydroxyapatite. The amount of hydroxyapatite phase increased with increasing voltage that was applied. The bonding strength became slightly weaker after a higher voltage was applied. But the bonding strengths of all the coatings were consistently higher than 37 MPa, which met the requirement of implant biomaterials. All coatings exhibited higher corrosion resistances and lower hydrogen evolution rate than the bare AZ31 Mg substrate, implying that the degradation rate of the AZ31 Mg alloy was enhanced by the hydroxyapatite-containing coatings. The results indicate that the present treatment of applying hydroxyapatite-containing coatings is a promising technique for the degradable Mg-based biomaterials for orthopedic applications.

Study of the Plutino Object (208996) 2003 AZ84 from Stellar Occultations: Size, Shape, and Topographic Features

NASA Astrophysics Data System (ADS)

Dias-Oliveira, A.; Sicardy, B.; Ortiz, J. L.; Braga-Ribas, F.; Leiva, R.; Vieira-Martins, R.; Benedetti-Rossi, G.; Camargo, J. I. B.; Assafin, M.; Gomes-Júnior, A. R.; Baug, T.; Chandrasekhar, T.; Desmars, J.; Duffard, R.; Santos-Sanz, P.; Ergang, Z.; Ganesh, S.; Ikari, Y.; Irawati, P.; Jain, J.; Liying, Z.; Richichi, A.; Shengbang, Q.; Behrend, R.; Benkhaldoun, Z.; Brosch, N.; Daassou, A.; Frappa, E.; Gal-Yam, A.; Garcia-Lozano, R.; Gillon, M.; Jehin, E.; Kaspi, S.; Klotz, A.; Lecacheux, J.; Mahasena, P.; Manfroid, J.; Manulis, I.; Maury, A.; Mohan, V.; Morales, N.; Ofek, E.; Rinner, C.; Sharma, A.; Sposetti, S.; Tanga, P.; Thirouin, A.; Vachier, F.; Widemann, T.; Asai, A.; Hayato, Watanabe; Hiroyuki, Watanabe; Owada, M.; Yamamura, H.; Hayamizu, T.; Bradshaw, J.; Kerr, S.; Tomioka, H.; Andersson, S.; Dangl, G.; Haymes, T.; Naves, R.; Wortmann, G.

2017-07-01

We present results derived from four stellar occultations by the plutino object (208996) 2003 AZ84, detected on 2011 January 8 (single-chord event), 2012 February 3 (multi-chord), 2013 December 2 (single-chord), and 2014 November 15 (multi-chord). Our observations rule out an oblate spheroid solution for 2003 AZ84's shape. Instead, assuming hydrostatic equilibrium, we find that a Jacobi triaxial solution with semiaxes (470+/- 20)× (383+/- 10)× (245+/- 8) km can better account for all our occultation observations. Combining these dimensions with the rotation period of the body (6.75 hr) and the amplitude of its rotation light curve, we derive a density ρ =0.87+/- 0.01 g cm-3, a geometric albedo {p}V=0.097+/- 0.009. A grazing chord observed during the 2014 occultation reveals a topographic feature along 2003 AZ84's limb, which can be interpreted as an abrupt chasm of width ˜23 km and depth > 8 km, or a smooth depression of width ˜80 km and depth ˜13 km (or an intermediate feature between those two extremes).

Surface characterization and cytocompatibility evaluation of silanized magnesium alloy AZ91 for biomedical applications

NASA Astrophysics Data System (ADS)

Witecka, Agnieszka; Yamamoto, Akiko; Dybiec, Henryk; Swieszkowski, Wojciech

2012-12-01

Mg alloys with high Al contents have superior corrosion resistance in aqueous environments, but poor cytocompatibility compared to that of pure Mg. We have silanized the cast AZ91 alloy to improve its cytocompatibility using five different silanes: ethyltriethoxysilane (S1), 3-aminopropyltriethoxysilane (S2), 3-isocyanatopyltriethoxysilane (S3), phenyltriethoxysilane (S4) and octadecyltriethoxysilane (S5). The surface hydrophilicity/hydrophobicity was evaluated by water contact angle measurements. X-ray photoelectron analysis was performed to investigate the changes in surface states and chemical composition. All silane reagents increased adsorption of the albumin to the modified surface. In vitro cytocompatibility evaluation revealed that silanization improved cell growth on AZ91 modified by silane S1. Measurement of the concentration of Mg2+ ions released during the cell culture indicated that silanization does not affect substrate degradation.

Tensile properties of AZ11A-0 magnesium-alloy sheet under rapid-heating and constant temperature

NASA Technical Reports Server (NTRS)

Kurg, Ivo M

1956-01-01

Specimens of AZ31A-0 magnesium alloy sheet were heated to rupture at nominal rates of 0.2 F to 100 F per second under constant tensile load conditions. The data are presented and compared with the results of conventional tensile stress-strain tests at elevated temperatures after 1.2-hour exposure. A temperature-rate parameter was used to construct master curves from which stresses and temperatures for yield and rupture can be predicted under rapid-heating conditions. A comparison of the elevated-temperature tensile properties of AZ31A-0 and HK31XA-H24 magnesium-alloy sheet under both constant-temperature and rapid-heating conditions is included.

77 FR 22475 - Standard Instrument Approach Procedures, and Takeoff Minimums and Obstacle Departure Procedures...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-04-16

..., Orig, CANCELLED Fort Huachuca Sierra Vista, AZ, Sierra Vista Muni-Libby AAF, RADAR-1, Orig Fort Huachuca Sierra Vista, AZ, Sierra Vista Muni-Libby AAF, RADAR-2, Orig Lake Havasu City, AZ, Lake Havasu... Opelousas, LA, St Landry Parish-Ahart Field, NDB RWY 18, Amdt 3 Opelousas, LA, St Landry Parish-Ahart Field...

Project W-314 specific test and evaluation plan for AZ tank farm upgrades

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hays, W.H.

1998-08-12

The purpose of this Specific Test and Evaluation Plan (STEP) is to provide a detailed written plan for the systematic testing of modifications made by the addition of the SN-631 transfer line from the AZ-O1A pit to the AZ-02A pit by the W-314 Project. The STEP develops the outline for test procedures that verify the system`s performance to the established Project design criteria. The STEP is a lower tier document based on the W-314 Test and Evaluation P1 an (TEP). Testing includes Validations and Verifications (e.g., Commercial Grade Item Dedication activities, etc), Factory Tests and Inspections (FTIs), installation tests andmore » inspections, Construction Tests and Inspections (CTIs), Acceptance Test Procedures (ATPs), Pre-Operational Test Procedures (POTPs), and Operational Test Procedures (OTPs). The STEP will be utilized in conjunction with the TEP for verification and validation.« less

Monitoring exposure of brown bullheads and benthic macroinvertebrates to sediment contaminants in the Ashtabula River before, during, and after remediation.

PubMed

Meier, John R; Lazorchak, James M; Mills, Marc; Wernsing, Paul; Baumann, Paul C

2015-06-01

In 2007, approximately 420,500 cubic meters of contaminated sediment were removed from the Ashtabula River by dredging. The primary objective of the present study was to monitor contaminant exposure in fish and macroinvertebrates before, during, and after dredging. This was done by measuring tissue concentrations of polychlorinated biphenyl (PCB) and polycyclic aromatic hydrocarbon (PAH) in brown bullhead catfish (Ameriurus nebulosa) and in benthic macroinvertebrates, assessing changes in DNA damage in fish liver and blood, and scoring external and histopathological lesions and anomalies in the fish. In surficial sediment PCBs and PAHs were also quantified in conjunction with the biological sampling. The results show a significant reduction in contaminant levels in both fish and macroinvertebrates following dredging, indicating the effectiveness of the remediation in reducing exposure of biota to the primary contaminants of concern. Similarly, DNA damage levels in fish collected from the Ashtabula River significantly declined following dredging; however, a similar reduction in DNA damage over time was seen in fish collected from a reference site (Conneaut Creek), making interpretation difficult. Macroinvertebrate PCB concentrations were reflective of the sediment concentrations in the areas where Hester-Dendy samplers were deployed for macroinvertebrate collection. The present study demonstrates that these methods can be used to evaluate and assess the effectiveness of remediation techniques at contaminated sediment sites. Published 2015 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Effect of temperature on the anisotropy of AZ31 magnesium alloy rolling sheet under high strain rate deformation

NASA Astrophysics Data System (ADS)

Liu, Yanyu; Mao, Pingli; Zhang, Feng; Liu, Zheng; Wang, Zhi

2018-04-01

In order to investigate the effect of temperature on the anisotropic behaviour of AZ31 magnesium alloy rolling sheet under high strain rate deformation, the Split Hopkinson Pressure Bar was used to analyse the dynamic mechanical properties of AZ31 magnesium alloy rolling sheet in three directions, rolling direction(RD), transverse direction (TD) and normal direction (ND). The texture of the rolling sheet was characterised by X-ray analysis and the microstructure prior and after high strain rate deformation was observed by optical microscope (OM). The results demonstrated that AZ31magnesium alloy rolling sheet has strong initial {0 0 0 2} texture, which resulted at the obvious anisotropy in high strain rate deformation at 20 °C. The anisotropy reflected in stress-strain curve, yield stress, peak stress and microstructure. The anisotropy became much weaker when the deformation temperature increased up to 250 °C. Continuing to increase the deformation temperature to 350 °C the anisotropy of AZ31 rolling sheet essentially disappeared. The decreasing tendency of anisotropy with increasing temperature was due to the fact that when the deformation temperature increased, the critical resolved shear stress (CRSS) for pyramidal 〈c + a〉 slip, which was the predominant slip mechanism for ND, decreased close to that of twinning, which was the predominant deformation mechanism for RD and TD. The deformation mechanism at different directions and temperatures and the Schmid factor (SF) at different directions were discussed in the present paper.

Flame-resistant Ca-containing AZ31 magnesium alloy sheets with good mechanical properties fabricated by a combination of strip casting and high-ratio differential speed rolling methods

NASA Astrophysics Data System (ADS)

Kim, Y. H.; Kim, W. J.

2015-03-01

This study reported that a combination of strip casting and high-ratio differential speed rolling (HRDSR) can produce flame-resistant Mg alloy sheets (0.7 wt%Ca-AZ31: 0.7Ca-AZ31) with good room-temperature mechanical properties and high-temperature formability. HRDSR effectively refined the coarse microstructure of the strip-casting processed 0.7Ca-AZ31 alloy. As the result, the (true) grain size was reduced to as small as 2.7 μm and the (Mg, Al)2Ca phase was broken up to fine particles with an average sizes of 0.5 μm. Due to the advantage of having such a highly refined microstructure, the HRDSR-processed 0.7Ca-AZ31 alloy sheet exhibited a high yield stress over 300 MPa and good superplasticity at elevated temperatures. The deformation mechanism of the fine-grained 0.7Ca-AZ31 alloy in the superplastic regime was identified to be grainboundary-diffusion or lattice-diffusion controlled grain boundary sliding.

77 FR 73480 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-10

... Florence, AZ 85232. 85132. Yavapai Town of Camp Verde The Honorable Bob Town Clerk's http://www.r9map.org... Camp Main Street, Room 040131-102IAC.pdf. Verde, 473 South 102, Camp Verde, Main Street, AZ 86322. Suite 102, Camp Verde, AZ 86322. California: Orange City of Irvine (12- The Honorable 1 Civic Center...

75 FR 28778 - Magma Flood Retarding Structure (FRS) Supplemental Watershed Plan, Pinal County, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-24

... INFORMATION: The environmental assessment of this federally assisted action indicates that the project will... DEPARTMENT OF AGRICULTURE Natural Resources Conservation Service Magma Flood Retarding Structure (FRS) Supplemental Watershed Plan, Pinal County, AZ AGENCY: Natural Resources Conservation Service...

Influence of Sodium Silicate/Sodium Alginate Additives on Discharge Performance of Mg-Air Battery Based on AZ61 Alloy

NASA Astrophysics Data System (ADS)

Ma, Jingling; Wang, Guangxin; Li, Yaqiong; Li, Wuhui; Ren, Fengzhang

2018-04-01

The application of Mg-air batteries is limited due to passivation and self-corrosion of anode alloys in electrolyte. In effort of solving this problem, the present work studied the influence of sodium silicate (SS)/sodium alginate (SA) on electrochemical behaviors of AZ61 alloy in NaCl solution by circle potentiodynamic polarization and galvanostatic discharge. The corrosion morphology and discharge product were examined by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Results have shown that sodium silicate/sodium alginate inhibitors have an apparent effect on the self-corrosion of AZ61 alloy without affecting its discharge performance. The discharge capacity and the anodic utilization for Mg-air battery in a 0.6 M NaCl + 0.01 M SS +0.04 M SA solution are measured to be 1397 mAhg-1 and 48.2%, respectively. Electrochemical impedance spectroscopy (EIS) and SEM investigation have confirmed that the sodium silicate/sodium alginate inhibitor can obviously decrease the self-corrosion of AZ61 alloy. SEM and XRD diffraction examinations suggest that the inhibiting mechanism is due to the formation of a compact and "cracked mud" layer. AZ61 alloy can be used as the anode for Mg-air battery in a solution of 0.6 M NaCl + 0.01 M SS +0.04 M SA.

Influence of Sodium Silicate/Sodium Alginate Additives on Discharge Performance of Mg-Air Battery Based on AZ61 Alloy

NASA Astrophysics Data System (ADS)

Ma, Jingling; Wang, Guangxin; Li, Yaqiong; Li, Wuhui; Ren, Fengzhang

2018-05-01

The application of Mg-air batteries is limited due to passivation and self-corrosion of anode alloys in electrolyte. In effort of solving this problem, the present work studied the influence of sodium silicate (SS)/sodium alginate (SA) on electrochemical behaviors of AZ61 alloy in NaCl solution by circle potentiodynamic polarization and galvanostatic discharge. The corrosion morphology and discharge product were examined by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Results have shown that sodium silicate/sodium alginate inhibitors have an apparent effect on the self-corrosion of AZ61 alloy without affecting its discharge performance. The discharge capacity and the anodic utilization for Mg-air battery in a 0.6 M NaCl + 0.01 M SS +0.04 M SA solution are measured to be 1397 mAhg-1 and 48.2%, respectively. Electrochemical impedance spectroscopy (EIS) and SEM investigation have confirmed that the sodium silicate/sodium alginate inhibitor can obviously decrease the self-corrosion of AZ61 alloy. SEM and XRD diffraction examinations suggest that the inhibiting mechanism is due to the formation of a compact and "cracked mud" layer. AZ61 alloy can be used as the anode for Mg-air battery in a solution of 0.6 M NaCl + 0.01 M SS +0.04 M SA.

Electrochemical Corrosion and In vitro Biocompatibility Performance of AZ31Mg/Al2O3 Nanocomposite in Simulated Body Fluid

NASA Astrophysics Data System (ADS)

Madhan Kumar, A.; Fida Hassan, S.; Sorour, Ahmad A.; Paramsothy, M.; Gupta, M.

2018-06-01

In this present investigation, AZ31 alloy nanocomposite was prepared with the inclusion of Al2O3 nanoparticles using innovative disintegrated melt deposition (DMD) process followed by hot extrusion to improve the corrosion resistance and in vitro biocompatibility in simulated body fluid (SBF). This investigation systematically inspected the degradation performances of AZ31 alloy with Al2O3 nanoparticles through hydrogen evolution, weight loss and electrochemical methods in SBF. Further, the surface microstructure with the in vitro mineralization of the alloys in SBF was characterized by XRD, XPS, and SEM/EDS analysis. It was seen that the addition of Al2O3 nanoparticles significantly decreased the weight loss of AZ31 alloy substrates after 336 h of exposure in SBF. The corrosion resistance of the monolithic and nanocomposite samples was evaluated using potentiodynamic polarization tests, electrochemical impedance spectroscopy measurements in short- and long-term periods. Accordingly, the electrochemical analysis in SBF showed that the corrosion resistance performance of the AZ31 alloy enhanced considerably due to the incorporation of Al2O3 nanoparticles as reinforcement. Moreover, the rapid formation of bone-like apatite layer on the surface of the nanocomposite substrate demonstrated a good bioactivity of the nanocomposite samples in SBF.

Tumor Prevalence and Biomarkers of Exposure and Response in Brown Bullheads (Ameiurus nebulosus) from the Tidal Potomac River Watershed

USGS Publications Warehouse

Pinkney, A.E.; Harshbarger, J.C.; May, E.B.; Melancon, M.J.

2000-01-01

Four groups of thirty brown bullheads (Ameiurus nebulosus) were collected from the tidal Potomac River watershed to survey tumor prevalence in relation to contaminant exposure. Fish were obtained from the Quantico embayment, near a Superfund site that released polychlorinated biphenyls (PCBs) and DDT compounds; Neabsco Creek,.a tributary with petroleum inputs from upstream areas and marinas; and the Anacostia River (both in spring and fall),where sediment is contaminated with polynuclear aromatic hydrocarbons (PAHs), PCBs, and organochlorine pesticides. Fish were also collected from the Tuckahoe River, on the Eastern Shore of Maryland, as a reference. Fish were necropsied and examined grossly and histopathologically for skin and liver neoplasms. Cytochrome P450 activity, bile PAH metabolites, and muscle organochlorine pesticide/PCB concentrations were determined in randomly selected individuals. There were significant differences among sites in liver tumor prevalence: Anacostia (spring)-50%, Anacostia (fall)-60%, Neabsco-17%, Quantico-7%, Tuckahoe-10%. Skin tumor prevalences were also significantly different: Anacostia (spring)-37%, Anacostia (fall)-10%, Neabsco-3%, Quantico-3%, Tuckahoe-0%. Tumor prevalences in Anacostia fish were comparable to those at contaminated sites in the Great Lakes. PAH concentrations were higher in Anacostia sediments than at the other sites and there were significantly higher concentrations of PAH metabolites in bile of the Anacostia fish. At present, there are insufficient data, however, to establish a cause-effect linkage with a particular class of contaminants. Tumor surveys in selected species are recommended for monitoring the status and remediation of Regions of Concern and other areas in the Chesapeake Bay watershed.

[Itinerant physicians, the art of healing and doctors in national history (Mexico City, 1877-1911)].

PubMed

Agostoni, Claudia

2008-01-01

The uncertainty and mistrust towards the presence and activities of academic medical practitioners in Mexico City during the Porfirio Díaz government (1877-1911) convinced these professionals that is was essential to create, strengthen and transmit a respectable, competent and homogeneous image of the profession. To this purpose they recovered, recreated and adapted the ethical maxims of the occidental medical culture to their professional work, and rescued eminent medical figures of Mexico's convulse nineteenth century from being lost in the oblivion of history. Their goal - as it will be expounded in the following pages - was to respond, oppose and neutralize the criticism and disbelief expressed by the public against their professional performance.

2003 AZ84: Size, shape, albedo and first detection of topographic features

NASA Astrophysics Data System (ADS)

Dias-Oliveira, Alex; Sicardy, Bruno; Ortiz, Jose-Luis; Braga-Ribas, Felipe; Vieira-Martins, Roberto; BENEDETTI Rossi, Gustavo; camargo, julio; Assafin, Marcelo; Gomes-Júnior, Altair; Baug, Tapas; Chandrasekhar, Thyagarajan; Duffard, Rene; Ergang, Zhao; Ganesh Ganesh, Shashikiran; Ikari, Yasukazu; Irawati, Puji; Jain, Rajmal; Liying, Zhu; Richichi, Andrea; Shengbang, Qian; Behrend, Raoul; Benkhaldoun, Zouhair; Brosch, Noah; Daassou, Ahmed; Gal-Yam's, Avishay; Garcia-Lozano, Rubén; Gillon, Michael; Jehin, Emmanuel; Kaspi, Shai; Klotz, Alain; Lecacheux, Jean; Mahasena, Putra; Manfroid, Jean; Manulis, Ilan; Maury, Alain; Mohan, Vijay; Morales, Nicolas; Rinner, Claudine; Roques, françoise; Sharma, Amar; Sposetti, Stefano; Tanga, Paolo; Thirouin, Audrey; Vachier, Frederic; Widemann, Thomas

2016-10-01

We analyze two multi-chord stellar occultations by the Trans-Neptunian Object (TNO) 2003 AZ84 observed on February 3, 2012 and November 15, 2014.They provide different elliptical limb fits that are consistent to within their respective error bars, but could also suggest a possible precession of the object (assumed here to be a Maclaurin spheroid). The derived equatorial radius and oblateness are Re = 393 ± 7 km and ɛ = 0.057 in 2014 and Re = 414 ± 13 km and ɛ = 0.165 in 2012, respectively. Those results are consistent with single-chord events observed in January 2011 and December 2013. The figures above provide geometric visual albedos of pV(2014) = 0.112 ± 0.008 and pV(2012) = 0.114 ± 0.020. Using the Maclaurin assumption, combined with possible rotational periods of 6.67 h and 10.56 h, we estimate density upper limits of 1.89 ± 0.16g/cm3 and 0.77 ± 0.07g/cm3 for the two dates, respectively.The 2014 event provides (for the first time during a TNO occultation) a grazing chord with a gradual disappearance of the star behind 2003AZ84's limb that lasts for more than 10 seconds. We rule out the possibility of a localized dust concentration as it would imply very high optical depth for that cloud. We favor a local topographic feature (chasm) with minimum width and depth of 22 ± 2.5 km and 7 ± 2.0 km, respectively. Features with similar depths are in fact observed on Pluto's main satellite, Charon, which has a radius of about 605 km, comparable to that of 2003AZ84.

Quantitative regulation of histone variant H2A.Z during cell cycle by ubiquitin proteasome system and SUMO-targeted ubiquitin ligases.

PubMed

Takahashi, Daisuke; Orihara, Yuki; Kitagawa, Saho; Kusakabe, Masayuki; Shintani, Takahiro; Oma, Yukako; Harata, Masahiko

2017-08-01

Quantitative control of histones and histone variants during cell cycle is relevant to their epigenetic functions. We found that the level of yeast histone variant H2A.Z in the G2/M-phase is actively kept low by the ubiquitin proteasome system and SUMO-targeted ubiquitin ligases. Overexpression of H2A.Z induced defects in mitotic progression, suggesting functional importance of this quantitative control.

In vitro degradation, hemolysis, and cytocompatibility of PEO/PLLA composite coating on biodegradable AZ31 alloy.

PubMed

Wei, Zhongling; Tian, Peng; Liu, Xuanyong; Zhou, Bangxin

2015-02-01

Magnesium and its alloys have large potential as degradable and absorbable biomaterials because of their mechanical properties and biocompatibility. However, their corrosion resistance is usually inadequate especially in physiological environment, which limits their broad applications in biomedical areas. In this work, plasma electrolytic oxidized/poly(l-lactide) (PEO/PLLA) composite coating was successfully fabricated on biodegradable AZ31 alloy by combing PEO process and sealing with PLLA. The microstructure, elemental composition, and phase composition of the PEO/PLLA composite coating were investigated. The in vitro degradation of the PEO/PLLA composite coating in simulated body fluid (SBF) was also systematically evaluated. The results revealed that the PEO/PLLA composite coating improved the corrosion resistance of AZ31 alloy significantly. The corrosion potential shifted from -1.663V to more positive position -1.317 V and the corrosion current density was reduced with six-order of magnitude. The Mg(2+) ions, hydrogen release, and pH value change of solution caused by degradation were all decreased significantly. Moreover, the PEO process played a critical role in sustaining the integrity of the implant in long-term service. The result of hemolysis test showed that the PEO/PLLA composite coating vested AZ31 alloy a low hemolysis ratio (0.806 ± 0.771)%, which is much lower than the safe value of 5% according to ISO 10993-4. For the cytocompatibility test, compared with bare AZ31 alloy and PEO coating, MC3T3-E1 cells showed much better adhesion and proliferation on the PEO/PLLA composite coating with nearly 4-fold increase of cells after 7-day cultivation, indicating that the PEO/PLLA composite coating has good biocompatibility for biomedical applications. © 2014 Wiley Periodicals, Inc.

Effect of dissolution of magnesium alloy AZ31 on the rheological properties of Phosphate Buffer Saline.

PubMed

Riaz, Usman; Rakesh, Leela; Shabib, Ishraq; Haider, Waseem

2018-06-05

The issue of long-term incompatible interactions associated with the permanent implants can be eliminated by using various biodegradable metal implants. The recent research is focusing on the use of degradable stents to restore most of the hindrances of capillaries, and coronary arteries by supplying instant blood flow with constant mechanical and structural support. However, internal endothelialization and infection due to the corrosion of implanted stents are not easy to diagnose in the long run. In the recent past, magnesium (Mg) has been widely investigated for the cardiovascular stent applications. Here we made an attempt to understand the biodegradation process of Mg alloy stent by studying the degradation of Mg alloy AZ31 (3 wt% Aluminum, 1 wt% Zn) powder at various time-intervals in simulated blood fluid using the Rheological methods. The degradability of the Mg stent in the arteries affects the stress-strain properties of blood plasma and the subsequent flow conditions. Blood and plasma viscosities alter due to the degradation of Mg resulting from the stress-strain experienced in the blood vessels, in which the stent is inserted. Here our objective was to explore the influence of Mg degradation on the blood plasma viscosity by studying the viscoelastic properties. In this work, the effect of dissolution of Mg alloy AZ31 on the rheological properties of Phosphate Buffer Saline (PBS) at various time intervals have been investigated. The viscosity of the PBS-AZ31 solution increased with the dissolution of both slurries and percolated clear solution. The only exception was day-7 of the percolated clear solution, where viscosity was decreased showing a reduction in viscosity at initial stages of dissolution. The frequency sweep showed the tendency of the PBS-AZ31 gelation up to 100 rad/s frequency. Copyright © 2018 Elsevier Ltd. All rights reserved.

Validation of Airborne Visible-Infrared Imaging Spectrometer Data at Ray Mine, AZ

NASA Technical Reports Server (NTRS)

Lang, H.; Baloga, S.

1999-01-01

We validate 1997 Airborne Visible-Infrared Imaging Spectrometer (AVIRIS) reflectance spectra covering 0.4 meu - 2.4 meu from a stable, flat mineralogically characterized man-made target at Ray Mine, AZ, the site for an EPA/NASA assessment of the utility of remote sensing for monitoring acid drainage from an active open pit mine.

Surface characterization and cytocompatibility evaluation of silanized magnesium alloy AZ91 for biomedical applications

PubMed Central

Witecka, Agnieszka; Yamamoto, Akiko; Dybiec, Henryk; Swieszkowski, Wojciech

2012-01-01

Mg alloys with high Al contents have superior corrosion resistance in aqueous environments, but poor cytocompatibility compared to that of pure Mg. We have silanized the cast AZ91 alloy to improve its cytocompatibility using five different silanes: ethyltriethoxysilane (S1), 3-aminopropyltriethoxysilane (S2), 3-isocyanatopyltriethoxysilane (S3), phenyltriethoxysilane (S4) and octadecyltriethoxysilane (S5). The surface hydrophilicity/hydrophobicity was evaluated by water contact angle measurements. X-ray photoelectron analysis was performed to investigate the changes in surface states and chemical composition. All silane reagents increased adsorption of the albumin to the modified surface. In vitro cytocompatibility evaluation revealed that silanization improved cell growth on AZ91 modified by silane S1. Measurement of the concentration of Mg2+ ions released during the cell culture indicated that silanization does not affect substrate degradation. PMID:27877541

Stratigraphy and depositional environments of Fox Hills Formation (Late Cretaceous), Williston basin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, D.J.

The Fox Hills Formation (Late Cretaceous, Maestrichtian) was investigated where it crops out along the southern flank of the Williston basin and in the subsurface over the central portion of the basin, using 300 well logs. The formation is conformable and gradational with the underlying Pierre formation and can be either conformable or unconformable with the overlying Hell Creek Formation. The Fox Hills Formation is younger, thicker, and stratigraphically more complex to the east and is comprised of marginal marine sediments deposited during the final Cretaceous regression. To the west, the Fox Hills Formation is an upward-coarsening unit generally 30more » to 45 m thick and usually contains three members: from the base, Trail City, Timber Lake, and Colgate. The lower Fox Hills (Trail City, Timber Lake) is generally dominated by hummocky bedding and contains a variety of trace fossils, most notably Ophiomorpha. The upper Fox Hills (Colgate), where present, is characterized by cross-bedding. To the east, including the type area, the section is generally 80 to 100 m thick and contains four members: from the base, Trail City, Timber Lake, Iron Lightning (Colgate and Bullhead lithofacies), and Linton. In contrast to the section in the west, this section is as much as three times thicker, contains abundant body fossils, generally lacks hummocky bedding, and contains the Bullhead and Linton strata. In the west, the strata represent lower shoreface deposits, predominantly of storm origin (lower Fox Hills), overlain by upper shoreface and fluvial deposits (upper Fox Hills). In the east, the lower Fox Hills contains deposits of the lower shoreface (Trail City) and a barrier bar complex (Timber Lake), overlain by the deltaic deposits of the upper Fox Hills (Iron Lightning, Linton).« less

78 FR 78794 - Proposed Establishment of Class E Airspace; Flagstaff, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-27

...This action proposes to establish Class E airspace at the Flagstaff VHF Omni-Directional Radio Range/Distance Measuring Equipment (VOR/DME) navigation aid, Flagstaff, AZ, to facilitate vectoring of Instrument Flight Rules (IFR) aircraft under control of Albuquerque Air Route Traffic Control Center (ARTCC). The FAA is proposing this action to enhance the safety and management of aircraft operations within the National Airspace System.

The Effect of Ca Content on the Microstructure, Hardness and Tensile Properties of AZ81 Mg Cast Alloy

NASA Astrophysics Data System (ADS)

Allameh, S. H.; Emamy, M.

2017-05-01

The effects of various Ca contents (0.1-4 wt.%) on the microstructure and tensile properties of AZ81 magnesium alloy were investigated with the contribution of an analytical method. Ca addition (up to 1.0 wt.%) refined the alloy microstructure but further addition of Ca resulted in a coarse structure and introduced large dendrites within the grains. The changes in the microstructures revealed that Al4Ca, Al2Ca, τ-Mg32(A1,Zn)49 and ɛ-MgZn intermetallics are formed in the alloy as a result of Ca addition and Al consumption. The assessment of tensile properties of AZ81-1.0 wt.%Ca alloy showed the optimum values of yield strength and ultimate tensile strength, while AZ81-0.7 wt.%Ca alloy showed maximum elongation. The reduction in tensile properties of the cast alloy by the addition of more Ca was attributed to grain coarsening and evolution of a network of intermetallic compounds. FF study of tensile fractured surfaces indicated that Ca addition encourages brittle mode of fracture propagating through precipitated intermetallics in the structure.

The A-Z of Zika drug discovery.

PubMed

Mottin, Melina; Borba, Joyce V V B; Braga, Rodolpho C; Torres, Pedro H M; Martini, Matheus C; Proenca-Modena, Jose Luiz; Judice, Carla C; Costa, Fabio T M; Ekins, Sean; Perryman, Alexander L; Andrade, Carolina Horta

2018-06-20

Despite the recent outbreak of Zika virus (ZIKV), there are still no approved treatments, and early-stage compounds are probably many years away from approval. A comprehensive A-Z review of the recent advances in ZIKV drug discovery efforts is presented, highlighting drug repositioning and computationally guided compounds, including discovered viral and host cell inhibitors. Promising ZIKV molecular targets are also described and discussed, as well as targets belonging to the host cell, as new opportunities for ZIKV drug discovery. All this knowledge is not only crucial to advancing the fight against the Zika virus and other flaviviruses but also helps us prepare for the next emerging virus outbreak to which we will have to respond. Copyright © 2018. Published by Elsevier Ltd.

Submillimeter Galaxy Surveys with AzTEC

NASA Astrophysics Data System (ADS)

Wilson, Grant W.; Ade, P. A.; Aretxaga, I.; Austermann, J.; Battersby, C.; Bock, J. J.; Glenn, J.; Golwala, S. R.; Haig, D.; Hughes, D. H.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P. D.; Perera, T.; Scott, K.; Roberts, C.; Yoon, I.; Yun, M. S.

2006-06-01

We describe a recent large scale survey of the Submillimeter Galaxy (SMG) population by AzTEC, a 144 element bolometer camera, on the 15m diameter James Clerk Maxwell Telescope. From November 2005 to February 2006, over 400 hours of telescope time were spent imaging over 1 square degree of sky with an area weighted target sensitivity of 0.7 mJy rms. Several fields with large multi-wavelength data sets were mapped including the Subaru/XMM-Newton Deep Survey field, the Lockmann Hole, GOODS-N, and a subset of the COSMOS field. In addition we mapped fields spanning a wide range of environments including several regions with known mass over-density. Together this represents the largest/deepest survey of the SMG population. Herein we report on the technical details of the surveys, describe the reduction pipeline, and show preliminary results from a subsection of the survey fields.

VizieR Online Data Catalog: AzTEC/ASTE source catalogue (Aretxaga+, 2011)

NASA Astrophysics Data System (ADS)

Aretxaga, I.; Wilson, G. W.; Aguilar, E.; Alberts, S.; Scott, K. S.; Scoville, N.; Yun, M. S.; Austermann, J.; Downes, T. P.; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Kawabe, R.; Kohno, K.; Oshima, T.; Perera, T. A.; Tamura, Y.; Zeballos, M.

2013-02-01

We imaged a 2800 arcmin2 field centred at right ascension RA(J2000.0)=10:00:30.00 and declination DE(J2000.0)=2:14.00 with AzTEC mounted on the 10-m ASTE, located at 4800m in the Atacama Desert of Chile. The survey was carried out from 2008 October 20 to November 30. (1 data file).

78 FR 21138 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-09

...). Maricopa County Board 2801 West Durango of Supervisors, 301 Street, Phoenix, AZ West Jefferson 85009... 94533. Colorado: Adams (FEMA Docket No.: B-1280) City of Commerce City The Honorable Sean City Hall...

Investigation on the Effect of Pulsed Energy on Strength of Fillet Lap Laser Welded AZ31B Magnesium Alloys

NASA Astrophysics Data System (ADS)

Salleh, M. N. M.; Ishak, M.; Aiman, M. H.; Idris, S. R. A.; Romlay, F. R. M.

2017-09-01

AZ31B magnesium alloy have been hugely applied in the aerospace, automotive, and electronic industries. However, welding thin sheet AZ31B was challenging due to its properties which is easily to evaporated especially using conventional fusion welding method such as metal inert gas (MIG). Laser could be applied to weld this metal since it produces lower heat input. The application of fiber laser welding has been widely since this type of laser could produce better welding product especially in the automotive sectors. Low power fiber laser was used to weld this non-ferrous metal where pulse wave (PW) mode was used. Double fillet lap joint was applied to weld as thin as 0.6 mm thick of AZ31B and the effect of pulsed energy on the strength was studied. Bond width, throat length, and penetration depth also was studied related to the pulsed energy which effecting the joint. Higher pulsed energy contributes to the higher fracture load with angle of irradiation lower than 3 °

76 FR 61261 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-04

...-AA00 Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... Boating Association (IJSBA) World Finals. This temporary safety zone is necessary to provide for the... The International Jet Sports Boating Association is sponsoring the IJSBA World Finals. The event will...

Effects of Current Density on Microstructure and Corrosion Property of Coating on AZ31 Mg Alloy Processed via Plasma Electrolytic Oxidation

NASA Astrophysics Data System (ADS)

Lee, Kang Min; Einkhah, Feryar; Sani, Mohammad Ali Faghihi; Ko, Young Gun; Shin, Dong Hyuk

The effects of the current density on the micro structure and the corrosion property of the coating on AZ31 Mg alloy processed by the plasma electrolytic oxidation (PEO) were investigated. The present coatings were produced in an acid electrolyte containing K2ZrF6 with three different current densities, i.e., 100, 150, and 200 mA/cm2. From the microstructural observations, as the applied current density was increased, the diameter of micro-pores formed by the plasma discharges with high temperature increased. The coatings on AZ31 Mg alloy were mainly composed of MgO, ZrO2, MgF2, and Mg2Zr5O12 phases. The results of potentiodynamic polarization clearly showed that the PEO-treated AZ31 Mg alloy applied at 100 mA/cm2 of current density exhibited better corrosion properties than the others.

Analysis of metallic traces from the biodegradation of endomedullary AZ31 alloy temporary implants in rat organs after long implantation times.

PubMed

Bodelón, O G; Iglesias, C; Garrido, J; Clemente, C; Garcia-Alonso, M C; Escudero, M L

2015-08-04

AZ31 alloy has been tested as a biodegradable material in the form of endomedullary implants in female Wistar rat femurs. In order to evaluate the accumulation of potentially toxic elements from the biodegradation of the implant, magnesium (Mg), aluminium (Al), zinc (Zn), manganese (Mn) and fluorine (F) levels have been measured in different organs such as kidneys, liver, lungs, spleen and brain. Several factors that may influence accumulation have been taken into account: how long the implant has been in place, whether or not the bone is fractured, and the presence of an MgF2 protective coating on the implant. The main conclusions and the clinical relevance of the study have been that AZ31 endomedullary implants have a degradation rate of about 60% after 13 months, which is fully compatible with fracture consolidation. Neither bone fracture nor an MgF2 coating seems to influence the accumulation of trace elements in the studied organs. Aluminium is the only alloying element in this study that requires special attention. The increase in Al recovered from the sampled organs represents 3.95% of the amount contained in the AZ31 implant. Al accumulates in a statistically significant way in all the organs except the brain. All of this suggests that in long-term tests AZ31 may be a suitable material for osteosynthesis.

Complete Mitochondrial and Plastid Genomes of the Green Microalga Trebouxiophyceae sp. Strain MX-AZ01 Isolated from a Highly Acidic Geothermal Lake

PubMed Central

Martínez-Romero, Esperanza

2012-01-01

We report the complete organelle genome sequences of Trebouxiophyceae sp. strain MX-AZ01, an acidophilic green microalga isolated from a geothermal field in Mexico. This eukaryote has the remarkable ability to thrive in a particular shallow lake with emerging hot springs at the bottom, extremely low pH, and toxic heavy metal concentrations. Trebouxiophyceae sp. MX-AZ01 represents one of few described photosynthetic eukaryotes living in such a hostile environment. The organelle genomes of Trebouxiophyceae sp. MX-AZ01 are remarkable. The plastid genome sequence currently presents the highest G+C content for a trebouxiophyte. The mitochondrial genome sequence is the largest reported to date for the Trebouxiophyceae class of green algae. The analysis of the genome sequences presented here provides insight into the evolution of organelle genomes of trebouxiophytes and green algae. PMID:23104370

78 FR 23135 - Safety Zone; Blue Water Resort & Casino West Coast Nationals; Parker, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-18

...-AA00 Safety Zone; Blue Water Resort & Casino West Coast Nationals; Parker, AZ AGENCY: Coast Guard, DHS... Lake Moovalya region of the navigable waters of the Colorado River in Parker, Arizona for the Blue....). RPM Racing Enterprises is sponsoring the Blue Water Resort & Casino West Coast Nationals, which is...

75 FR 61619 - Safety Zone; IJSBA World Finals, Lower Colorado River, Lake Havasu, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-06

...-AA00 Safety Zone; IJSBA World Finals, Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... Sports Boating Association (IJSBA) World Finals. This temporary safety zone is necessary to provide for... notice of proposed rulemaking (NPRM) entitled Safety Zone; IJSBA World Finals in the Federal Register (75...

75 FR 5115 - Temporary Concession Contract for Lake Mead National Recreation Area, AZ/NV

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-01

... National Recreation Area, AZ/NV AGENCY: National Park Service, Department of the Interior. ACTION: Notice of intention to award temporary concession contract for Lake Mead National Recreation Area. SUMMARY: Pursuant to 36 CFR 51.24, public notice is hereby given that the National Park Service intends to award a...

Evaluation results for the positive deep-UV resist AZ DX 46

NASA Astrophysics Data System (ADS)

Spiess, Walter; Lynch, Thomas J.; Le Cornec, Charles; Escher, Gary C.; Kinoshita, Yoshiaki; Kochan, John; Kudo, Takanori; Masuda, Seiya; Mourier, Thierry; Nozaki, Yuko; Olson, Setha G.; Okazaki, Hiroshi; Padmanaban, Munirathna; Pawlowski, Georg; Przybilla, Klaus J.; Roeschert, Horst; Suehiro, Natusmi; Vinet, Francoise; Wengenroth, Horst

1994-05-01

This contribution emphasizes resist application site by communicating lithographic results for AZ DX 46, obtained using the GCA XLS 7800/31 stepper, NA equals 0.53, equipped with krypton fluoride excimer laser ((lambda) equals 248 nm), model 4500 D, as exposure source, delivered by Cymer Laser Technologies. As far as delay time experiments are concerned ASM-L PAS 5500/70 stepper, NA equals 0.42, was used in combination with Lambda Physik excimer laser, model 248 L.

Characterization of Tensile Deformation in AZ91D Mg Alloy Castings

NASA Astrophysics Data System (ADS)

Űnal, Ogün; Tiryakioǧlu, Murat

AZ91 cast Mg alloy specimens in T4 and T6 tempers have been tested in tension. True stress — true plastic strain relationship has been characterized by evaluating the fits to four constitutive equations. Moreover, work hardening behavior in both tempers has been investigated and how well the four constitutive equation can model this behavior has been tested. The effects of temper and structural quality on tensile properties and work hardening are discussed in the paper.

Thermal Microstructural Stability of AZ31 Magnesium after Severe Plastic Deformation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, John P.; Askari, Hesam A.; Hovanski, Yuri

2015-03-01

Both equal channel angular pressing and friction stir processing have the ability to refine the grain size of twin roll cast AZ31 magnesium and potentially improve its superplastic properties. This work used isochronal and isothermal heat treatments to investigate the microstructural stability of twin roll cast, equal channel angular pressed and friction stir processed AZ31 magnesium. For both heat treatment conditions, it was found that the twin roll casted and equal channel angular pressed materials were more stable than the friction stir processed material. Calculations of the grain growth kinetics showed that severe plastic deformation processing decreased the activation energymore » for grain boundary motion with the equal channel angular pressed material having the greatest Q value of the severely plastically deformed materials and that increasing the tool travel speed of the friction stir processed material improved microstructural stability. The Hollomon-Jaffe parameter was found to be an accurate means of identifying the annealing conditions that will result in substantial grain growth and loss of potential superplastic properties in the severely plastically deformed materials. In addition, Humphreys’s model of cellular microstructural stability accurately predicted the relative microstructural stability of the severely plastically deformed materials and with some modification, closely predicted the maximum grain size ratio achieved by the severely plastically deformed materials.« less

77 FR 2242 - Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-17

... FEDERAL COMMUNICATIONS COMMISSION 47 CFR Part 73 [MB Docket No. 08-85; RM-11427, RM-11517, RM-11518, RM-11519; DA 11- 2059] Radio Broadcasting Services; Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ, and Needles, CA AGENCY: Federal Communications Commission. ACTION: Proposed...

DOE Research and Development Accomplishments Site Index (A-Z)

Science.gov Websites

dropdown arrow Site Map A-Z Index Menu Synopsis A - Z Index A B C D E F G H I J K L M N O P Q R S T U V W X Buckminsterfullerene Curl Smalley Buckyball Curl Smalley TOP A B C D E F G H I J K L M N O P Q R S T U V W X Y Z C transcription Dresselhaus, Mildred (Millie) Drosophila dynamics TOP A B C D E F G H I J K L M N O P Q R S T U V

Influence of Accumulative Roll Bonding on the Texture and Tensile Properties of an AZ31 Magnesium Alloy Sheets

PubMed Central

Džugan, Ján; Németh, Gergely; Lukáč, Pavel; Bohlen, Jan

2018-01-01

Deformation behaviour of rolled AZ31 sheets that were subjected to the accumulative roll bonding was investigated. Substantially refined microstructure of samples was achieved after the first and second pass through the rolling mill. Sheets texture was investigated using an X-ray diffractometer. Samples for tensile tests were cut either parallel or perpendicular to the rolling direction. Tensile tests were performed at temperatures ranging from room temperature up to 300 °C. Tensile plastic anisotropy, different from the anisotropy observed in AZ31 sheets by other authors, was observed. This anisotropy decreases with an increasing number of rolling passes and increasing deformation temperature. Grain refinement and texture are the crucial factors influencing the deformation behaviour. PMID:29303975

Msc1 acts through histone H2A.Z to promote chromosome stability in Schizosaccharomyces pombe.

PubMed

Ahmed, Shakil; Dul, Barbara; Qiu, Xinxing; Walworth, Nancy C

2007-11-01

As a central component of the DNA damage checkpoint pathway, the conserved protein kinase Chk1 mediates cell cycle progression when DNA damage is generated. Msc1 was identified as a multicopy suppressor capable of facilitating survival in response to DNA damage of cells mutant for chk1. We demonstrate that loss of msc1 function results in an increased rate of chromosome loss and that an msc1 null allele exhibits genetic interactions with mutants in key kinetochore components. Multicopy expression of msc1 robustly suppresses a temperature-sensitive mutant (cnp1-1) in the centromere-specific histone H3 variant CENP-A, and localization of CENP-A to the centromere is compromised in msc1 null cells. We present several lines of evidence to suggest that Msc1 carries out its function through the histone H2A variant H2A.Z, encoded by pht1 in fission yeast. Like an msc1 mutant, a pht1 mutant also exhibits chromosome instability and genetic interactions with kinetochore mutants. Suppression of cnp1-1 by multicopy msc1 requires pht1. Likewise, suppression of the DNA damage sensitivity of a chk1 mutant by multicopy msc1 also requires pht1. We present the first genetic evidence that histone H2A.Z may participate in centromere function in fission yeast and propose that Msc1 acts through H2A.Z to promote chromosome stability and cell survival following DNA damage.

Msc1 Acts Through Histone H2A.Z to Promote Chromosome Stability in Schizosaccharomyces pombe

PubMed Central

Ahmed, Shakil; Dul, Barbara; Qiu, Xinxing; Walworth, Nancy C.

2007-01-01

As a central component of the DNA damage checkpoint pathway, the conserved protein kinase Chk1 mediates cell cycle progression when DNA damage is generated. Msc1 was identified as a multicopy suppressor capable of facilitating survival in response to DNA damage of cells mutant for chk1. We demonstrate that loss of msc1 function results in an increased rate of chromosome loss and that an msc1 null allele exhibits genetic interactions with mutants in key kinetochore components. Multicopy expression of msc1 robustly suppresses a temperature-sensitive mutant (cnp1-1) in the centromere-specific histone H3 variant CENP-A, and localization of CENP-A to the centromere is compromised in msc1 null cells. We present several lines of evidence to suggest that Msc1 carries out its function through the histone H2A variant H2A.Z, encoded by pht1 in fission yeast. Like an msc1 mutant, a pht1 mutant also exhibits chromosome instability and genetic interactions with kinetochore mutants. Suppression of cnp1-1 by multicopy msc1 requires pht1. Likewise, suppression of the DNA damage sensitivity of a chk1 mutant by multicopy msc1 also requires pht1. We present the first genetic evidence that histone H2A.Z may participate in centromere function in fission yeast and propose that Msc1 acts through H2A.Z to promote chromosome stability and cell survival following DNA damage. PMID:17947424

Az-Tech Medicine.

ERIC Educational Resources Information Center

Nicholson, Rob

2000-01-01

Created in 1552 as a gift for Spain's king, the Badianus Manuscript is a repository of Aztec traditional medicinal knowledge and contains the earliest surviving illustrations of New World plants. At the College of Santa Cruz (Mexico City) for Aztec nobility, an Aztec healer who became the college physician compiled plant descriptions and medicinal…

75 FR 38754 - Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-06

...-AA00 Safety Zone; IJSBA World Finals; Lower Colorado River, Lake Havasu, AZ AGENCY: Coast Guard, DHS... navigable waters of Lake Havasu on the lower Colorado River in support of the IJSBA World Finals. This... International Jet Sports Boating Association is sponsoring the IJSBA World Finals. The event will consist of 300...

New LMT High Resolution Imaging and CO Spectroscopic Studies of the Brightest AzTEC 1.1mm Sources

NASA Astrophysics Data System (ADS)

Yun, Min S.; Aretxaga, Itziar; Hughes, David; Montana, A.; Pope, A.; Bruzual, Gustavo; Ferrusca, D.; Rosa Gonzalez, D.; Sanchez-Arguelles, D.; Narayanan, G.; Wilson, Grant; Gim, Hansung; Ibarra, H.; Mo, H.; Lowenthal, James; Zavala, J.; Carrasco, L.; Chavez, M.; Valazquez, M.; Zeballos, M.; Vega, O.; Schloerb, P.; Cybulsky, J. R.; Casey, Caitlin M.; Tang, Y.

2015-08-01

A substantial population of quiescent galaxies with stellar masses exceeding 10 billion solar masses have been found to z~4, suggesting a rapid formation and quenching of massive galaxies at z~6 or earlier. The submillimeter bright galaxies (SMGs) with SFR > 100-1000 solar masses per year represent natural candidates for the progenitor systems undergoing an epoch of rapid formation and cessation of stellar mass build up. Many of the most luminous SMGs are also extremely red and faint in the optical, suggesting a high redshift and are beyond the reach of the current optical spectroscopic redshift surveys. There is also a growing concern that these most luminous SMGs may be blends of several unrelated sources as a result of a poor angular resolution of the existing surveys (18" & 28" for the AzTEC 1.1mm surveys on JCMT and ASTE, respectively). We have obtained new 8" resolution AzTEC images of 40 brightest AzTEC sources previously found in the GOODS and COSMOS fields using the Large Millimeter Telescope (LMT) to examine the multiplicity question and for the identification of multi-wavelength counterparts. We have also conducted a CO redshift survey using the Redshift Search Receiver on the LMT. We will report the results of these analysis and several new CO redshifts.

Effect of Sm-Rich Phase on Corrosion Behavior of Hot-Extruded AZ31-1.5Sm Magnesium Alloy

NASA Astrophysics Data System (ADS)

Li, Xiao; Hu, Zhi; Yan, Hong; Wu, Xiaoquan; Xie, Hecong; Dong, Zhou

2018-05-01

The effects of Sm on the corrosion and microstructure behavior of hot-extruded AZ31 magnesium alloy were investigated by SEM, TEM, weight loss analysis, and electrochemical measurements. The results indicated that granular Al2Sm phase 4 μm in size in the hot-extruded AZ31 magnesium alloy modified with 1.5 wt.% Sm leads to significant grain refinement. The corrosion rate decreased from 15.98 × 10-4 to 11.19 × 10-4 g cm-2 h-1 in the transverse section and from 8.57 × 10-4 to 6.20 × 10-4 g cm-2 h-1 in the longitudinal section. Compared to the unmodified alloy, the corrosion potential of the Sm-modified alloy in the transverse and longitudinal sections increased by 98 and 62 mV, respectively, and the R ct value (charge transfer resistance) in the transverse and longitudinal sections of the modified alloy increased from 1764 and 1756 to 2928 and 2408 Ω cm2, respectively. The results showed that the corrosion resistance of hot-extruded AZ31 magnesium alloy was significantly improved by Sm addition due to the grain refinement, the decreased dislocation density, and the suppression of micro-galvanic corrosion caused by Al-Sm-(Mn) intermetallic compounds.

The Microstructure Evolution and Deformation Behavior of AZ80 During Gradient Increment Cyclic Loading

NASA Astrophysics Data System (ADS)

Ren, Lingbao; Quan, Gaofeng; Boehlert, Carl J.; Zhou, Mingyang; Guo, Yangyang; Fan, Lingling

2018-06-01

Cyclic loading-unloading uniaxial tension experiments were conducted at temperatures ranging between 293 K and 623 K and a strain rate of 10-3 s-1 to study the cyclic accumulated plastic deformation (CAP) behavior of extruded AZ80. The 673 K/4-h heat treatment to the as-extruded AZ80 led to a noticeable decrease in yield strength which was associated with both dissolution of the β-Mg17Al12 phase and growth of the matrix grain size. The critical number of cycles needed to soften the material (N c) decreased from 5 to 4 when the cyclic strain amplitude (ɛ a) increased from 3.3 to 5.0 pct for the as-extruded AZ80. The average cyclic hardening rate (Θ) increased from 11 to 23 MPa/cycle after heat treatment, and this was attributed to the more pronounced twinning process in the coarse-grained microstructure. During the 293 K to 473 K CAP deformation, the increasing accumulated cyclic tension strain may have accelerated the propagation of secondary twinning leading to the Lüders-like post-yield softening. Twinning was prevalent at low temperature (293 K to 473 K) in the ɛ a = 3.0 pct CAP deformation for the heat-treated alloy, and twin-assisted precipitation occurred during the 523 K CAP deformation, which implied that the high diffusivity in the twin boundary accelerated the heterogeneous nucleation of precipitates. The preferred cracking locations changed from twin boundaries to grain boundaries when the CAP deformation temperature increased from 473 K to 523 K. As for the 623 K CAP deformation, cavities initiated at the grain boundaries, and the volume fraction of the cracks/cavities increased from 0.01 to 0.05 with increasing temperature.

78 FR 65370 - Notice of Inventory Completion: Pima County Office of the Medical Examiner, Tucson, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-10-31

... Office for forensic analysis. The Pinal County Medical Examiner, Dr Rebecca Hsu, transferred the remains... were transferred to Pinal County Medical Examiner's Office for forensic analysis. The Pinal County.... Bruce Anderson, Forensic Anthropologist, PCOME, Tucson, AZ 85714, telephone (520) 243-8600...

Room Temperature Shear Band Development in Highly Twinned Wrought Magnesium AZ31B Sheet

NASA Astrophysics Data System (ADS)

Scott, Jon; Miles, Michael; Fullwood, David; Adams, Brent; Khosravani, Ali; Mishra, Raja K.

2013-01-01

Failure mechanisms were studied in wrought AZ31B magnesium alloy after forming under different strain paths. Optical micrographs were used to observe the shear band formation and regions of high twin density in samples strained under uniaxial, biaxial, and plane strain conditions. Interrupted testing at 4 pct effective strain increments, until failure, was used to observe the evolution of the microstructure. The results showed that shear bands, with a high percentage of twinned grains, appeared early in the samples strained under biaxial or plane strain tension. These bands are similar to those seen in uniaxial tension specimens just prior to failure where the uniaxial tensile ductility was much greater than that observed for plane strain or biaxial tension conditions. A forming limit diagram for AZ31B, which was developed from the strain data, showed that plane strain and biaxial tension had very similar limit strains; this contrasts with materials like steel or aluminum alloys, which typically have greater ductility in biaxial tension compared to plane strain tension.

Texture Development in a Friction Stir Lap-Welded AZ31B Magnesium Alloy

NASA Astrophysics Data System (ADS)

Naik, B. S.; Chen, D. L.; Cao, X.; Wanjara, P.

2014-09-01

The present study was aimed at characterizing the microstructure, texture, hardness, and tensile properties of an AZ31B-H24 Mg alloy that was friction stir lap welded (FSLWed) at varying tool rotational rates and welding speeds. Friction stir lap welding (FSLW) resulted in the presence of recrystallized grains and an associated hardness drop in the stir zone (SZ). Microstructural investigation showed that both the AZ31B-H24 Mg base metal (BM) and SZ contained β-Mg17Al12 and Al8Mn5 second phase particles. The AZ31B-H24 BM contained a type of basal texture (0001)<110> with the (0001) plane nearly parallel to the rolled sheet surface and <110> directions aligned in the rolling direction. FSLW resulted in the formation of another type of basal texture (0001)<100> in the SZ, where the basal planes (0001) became slightly tilted toward the transverse direction, and the prismatic planes (100) and pyramidal planes (101) exhibited a 30 deg + ( n - 1) × 60 deg rotation ( n = 1, 2, 3, …) with respect to the rolled sheet normal direction, due to the shear plastic flow near the pin surface that occurred from the intense local stirring. With increasing tool rotational rate and decreasing welding speed, the maximum intensity of the basal poles (0001) in the SZ decreased due to a higher degree of dynamic recrystallization that led to a weaker or more random texture. The tool rotational rate and welding speed had a strong effect on the failure load of FSLWed joints. A combination of relatively high welding speed (20 mm/s) and low tool rotational rate (1000 rpm) was observed to be capable of achieving a high failure load. This was attributed to the relatively small recrystallized grains and high intensity of the basal poles in the SZ arising from the low heat input as well as the presence of a small hooking defect.

Supplementary Environmental Baseline Studies and Evaluation of the St. Mary’s River 1980. Great Lakes-St. Lawrence Seaway Navigation Season Extension Program

DTIC Science & Technology

1981-07-01

Crossman, 1973) or because water temperatures are more favorable ( Crawshaw , 1975). Peaks in the length frequency distribution of brown bullhead at 50...269. Crawshaw , L. I. 1975. Attainment of final thermal preferendum in brown bullheads acclimated to different temperatures. Comp. Biochem. Physiol

Superplastic Behaviour of AZ61-F Magnesium Composite Materials

NASA Astrophysics Data System (ADS)

Besterci, Michal; Sülleiová, Katarína; Velgosová, Oksana; Balloková, Beáta; Huang, S.-J.

2017-03-01

Deformation of AZ61-F magnesium alloys with 1 wt % of Al2O3 phase was tested at different temperatures and different strain rates. It was shown that at temperatures 473-523 K and the highest strain rate applied from 1×10-2 s-1 to 1×10-4 s-1, a significant ductility growth was observed. The grain size of 0.6-0.8 μm was reached by severe plastic deformations by means of equal channel angular pressing (ECAP). Secondary Mg17Al12 and Al2O3 phases were identified. Maximum strain was gained at temperature of 473 K and strain rate of 1×10-4 s-1.

Review of Waste Management Symposium 2007, Tucson, AZ, USA

DOE PAGES

Luna, Robert E.; Yoshimura, R. H.

2007-03-01

The Waste Management Symposium 2007 is the most recent in a long series that has been held at Tucson, Arizona. The meeting has become extremely popular as a venue for technical exchange, marketing, and networking involving upward of 1800 persons involved with various aspects of radioactive waste management. However, in a break with tradition, the symposium organizers reported that next year’s Waste Management Symposium would be held at the Phoenix, AZ convention center. Additionally, most of the WM07 sessions dealt with the technical and institutional issues relating to the resolution of waste disposal and processing challenges, including a number ofmore » sessions dealing with related transport activities.« less

Influence of the β-Mg17Al12 Phase Morphology on the Corrosion Properties Of Az91hp Magnesium Alloy

NASA Astrophysics Data System (ADS)

Guo, Lingling; Zhang, Jumei

2017-09-01

The morphology of β-Mg17Al12 phase and corrosion behavior of AZ91HP magnesium alloy after spheroidizing treatment were investigated by optical microcope electrochemical and immersion tests in 3.5% NaCl at 25°C. The results show that the coarse divorced eutectic phase of AZ91HP cast magnesium alloy dissolve into Mg matrix during the isothermal process at 415°C, and the lameller β phase precipitated from magnesium solid solution as perlite-type precipitation during the slowly cooling. Next, the spheroidizing treatment at different temperatures for 20h was carried out, and the lameller β phase were spheroridizing by dissolved themselves. After spheroidizing treatment at 300°C for 20h, many small granular β phase are scattering within the magnesium matrix. The corrosion properties of AZ91HP magnesium alloy in 3.5% NaCl decreased obviously after spheroidizing treatment, the polarization measurement of the alloy can be up to -1.412V from -1.56V of the cast. The β-Mg17Al12 phase act as a corrosion barrier and hinder corrosion propagation, if the second phase is in the form of a spherical morphology.

Corrosion fatigue behaviors of two biomedical Mg alloys - AZ91D and WE43 - In simulated body fluid.

PubMed

Gu, X N; Zhou, W R; Zheng, Y F; Cheng, Y; Wei, S C; Zhong, S P; Xi, T F; Chen, L J

2010-12-01

Magnesium alloys have been recently developed as biodegradable implant materials, yet there has been no study concerning their corrosion fatigue properties under cyclic loading. In this study the die-cast AZ91D (A for aluminum 9%, Z for zinc 1% and D for a fourth phase) and extruded WE43 (W for yttrium 4%, E for rare earth mischmetal 3%) alloys were chosen to evaluate their fatigue and corrosion fatigue behaviors in simulated body fluid (SBF). The die-cast AZ91D alloy indicated a fatigue limit of 50MPa at 10⁷ cycles in air compared to 20MPa at 10⁶ cycles tested in SBF at 37°C. A fatigue limit of 110MPa at 10⁷ cycles in air was observed for extruded WE43 alloy compared to 40MPa at 10⁷ cycles tested in SBF at 37°C. The fatigue cracks initiated from the micropores when tested in air and from corrosion pits when tested in SBF, respectively. The overload zone of the extruded WE43 alloy exhibited a ductile fracture mode with deep dimples, in comparison to a brittle fracture mode for the die-cast AZ91D. The corrosion rate of the two experimental alloys increased under cyclic loading compared to that in the static immersion test. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Microstructural Analysis of Severe Plastic Deformed Twin Roll Cast AZ31 for the Optimization of Superplastic Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, John P.; Askari, Hesam A.; Heiden, Michael J.

2013-07-08

In recent years magnesium alloys have attracted significant attention as potential candidates to replace many of the heavier metals used in some automotive applications. However, the limited formability of magnesium and its alloys at room temperature has driven interest in the superplastic forming magnesium as an alternative shaping method. Severe plastic deformation techniques have become a well studied method of refining the grain size and modifying the microstructural characteristics of many magnesium alloys to achieve greater superplastic properties. In this study twin roll cast (TRC) AZ31 magnesium alloy was subjected to equal channel angular pressing (ECAP) and friction stir weldingmore » (FSW). The influence of these severe plastic deformation processes on the grain size, texture and grain boundary character distribution was investigated to identify the optimum severe plastic deformation process for the superplastic forming of AZ31.« less

Use of Friction Stir Processing for Improving Heat-Affected Zone Liquation Cracking Resistance of a Cast Magnesium Alloy AZ91D

NASA Astrophysics Data System (ADS)

Karthik, G. M.; Janaki Ram, G. D.; Kottada, Ravi Sankar

2017-12-01

In this work, a cast magnesium alloy AZ91D was friction stir processed. Detailed microstructural studies and Gleeble hot ductility tests were conducted on the as-cast and the FSPed samples to comparatively assess their heat-affected zone liquation cracking behavior. The results show that the use of FSP as a pretreatment to fusion welding can strikingly improve the heat-affected zone liquation cracking resistance of alloy AZ91D by reducing the amount and size of the low-melting eutectic β (Mg17Al12) as well as by refining the matrix grain size.

75 FR 11580 - Florida Power Corporation, City of Alachua, City of Bushnell, City of Gainesville, City of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-11

...- 0096] Florida Power Corporation, City of Alachua, City of Bushnell, City of Gainesville, City of Kissimmee, City of Leesburg, City of New Smyrna Beach and Utilities Commission, City of New Smyrna Beach, City of Ocala, Orlando Utilities Commission and City of Orlando, Seminole Electric Cooperative, Inc...

78 FR 72006 - Establishment of Class D Airspace and Class E Airspace; Laguna AAF, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-02

... establishes Class D airspace and Class E airspace at Laguna Army Air Field (AAF), (Yuma Proving Ground), Yuma...) within a 3.5- mile radius of Laguna AAF (Yuma Proving Ground), Yuma, AZ; and Class E airspace extending... scope of that authority as it establishes controlled airspace at Laguna AAF, (Yuma Proving Ground), Yuma...

Experimental and Numerical Study on the Deformation Mechanism in AZ31B Mg Alloy Sheets Under Pulsed Electric-Assisted Tensile and Compressive Tests

NASA Astrophysics Data System (ADS)

Lee, Jinwoo; Kim, Se-Jong; Lee, Myoung-Gyu; Song, Jung Han; Choi, Seogou; Han, Heung Nam; Kim, Daeyong

2016-06-01

The uniaxial tensile and compressive stress-strain responses of AZ31B magnesium alloy sheet under pulsed electric current are reported. Tension and compression tests with pulsed electric current showed that flow stresses dropped instantaneously when the electric pulses were applied. Thermo-mechanical-electrical finite element analyses were also performed to investigate the effects of Joule heating and electro-plasticity on the flow responses of AZ31B sheets under electric-pulsed tension and compression tests. The proposed finite element simulations could reproduce the measured uniaxial tensile and compressive stress-strain curves under pulsed electric currents, when the temperature-dependent flow stress hardening model and thermal properties of AZ31B sheet were properly described in the simulations. In particular, the simulation results that fit best with experimental results showed that almost 100 pct of the electric current was subject to transform into Joule heating during electrically assisted tensile and compressive tests.

CESIUM REMOVAL FROM TANKS 241-AN-103 & 241-SX-105 & 241-AZ-101/102 COMPOSITE FOR TESTING IN BENCH SCALE STEAM REFORMER

DOE Office of Scientific and Technical Information (OSTI.GOV)

DUNCAN JB; HUBER HJ

2011-06-08

This report documents the preparation of three actual Hanford tank waste samples for shipment to the Savannah River National Laboratory (SRNL). Two of the samples were dissolved saltcakes from tank 241-AN-103 (hereafter AN-103) and tank 241-SX-105 (hereafter SX-105); one sample was a supernate composite from tanks 241-AZ-101 and 241-AZ-102 (hereafter AZ-101/102). The preparation of the samples was executed following the test plans LAB-PLAN-10-00006, Test Plan for the Preparation of Samples from Hanford Tanks 241-SX-105, 241-AN-103, 241-AN-107, and LAB-PLN-10-00014, Test Plan for the Preparation of a Composite Sample from Hanford Tanks 241-AZ-101 and 241-AZ-102 for Steam Reformer Testing at the Savannahmore » River National Laboratory. All procedural steps were recorded in laboratory notebook HNF-N-274 3. Sample breakdown diagrams for AN-103 and SX-105 are presented in Appendix A. The tank samples were prepared in support of a series of treatability studies of the Fluidized Bed Steam Reforming (FBSR) process using a Bench-Scale Reformer (BSR) at SRNL. Tests with simulants have shown that the FBSR mineralized waste form is comparable to low-activity waste glass with respect to environmental durability (WSRC-STI-2008-00268, Mineralization of Radioactive Wastes by Fluidized Bed Steam Reforming (FBSR): Comparisons to Vitreous Waste Forms and Pertinent Durability Testing). However, a rigorous assessment requires long-term performance data from FB SR product formed from actual Hanford tank waste. Washington River Protection Solutions, LLC (WRPS) has initiated a Waste Form Qualification Program (WP-S.2.1-20 1 0-00 1, Fluidized Bed Steam Reformer Low-level Waste Form Qualification) to gather the data required to demonstrate that an adequate FBSR mineralized waste form can be produced. The documentation of the selection process of the three tank samples has been separately reported in RPP-48824, 'Sample Selection Process for Bench-Scale Steam Reforming Treatability Studies

A 1.1mm AzTEC Survey Tracing Accelerated Galaxy Formation Towards a Protocluster at z 3.8

NASA Astrophysics Data System (ADS)

Hughes, David H.; Montana, A.; Aretxaga, I.; Plionis, M.; Porras, A.; Wagg, J.; Gaztanaga, E.; Huang, J.; Fazio, G.; Wilson, G.; Yun, M.; Lowenthal, J.; Perera, T.; Austermann, J.; Scott, K.; Dunlop, J.; Ivison, R.; Stevens, J.; Smail, I.; Appleton, P.

2006-12-01

Aztec has recently conducted a sensitive, wide-area (300 sq. Armin's) continuum survey at 1.1mm using the 15-m James Clerk Maxwell Telescope towards 4C41.17, a powerful high-redshift (z 3.8) radio galaxy. These Aztec data, which cover an area >40 times larger than our previous SCUBA survey, reveal a significant over-density of luminous, massive dust-enshrouded galaxies, compared to the results from lower-redshift blank-field sub-mm surveys. One natural interpretation of these new AzTEC data is that the over-density is tracing a large (5 x 5 Mpc) "proto-cluster" structure at z 3.8 associated with the environment of 4C41.17, within which the formation of ultra-luminous starburst galaxies (with rest-frame FIR luminosities >5 x 1012 Lsun or SFRs > 500 Msun/yr) is taking place at an accelerated rate. Proving the physical association of these massive optically-faint starbursts with the environment of this high-z AGN, and not with the blank-field sub-mm population, for which 50% of the population lies at 1.9 < z < 2.9, remains an outstanding problem. In this presentation we will describe the AzTEC survey, the empirical evidence for this protocluster structure in the early universe, and the planned multi-wavelength follow-up observations of the brightest AzTEC sources towards 4C41.17 that may demonstrate that we are witnessing accelerated galaxy formation, via an increased rate of merging gas-rich galaxies within a rapidly-developing gravitational potential. AzTEC is one of the suite of instruments destined for the 50-m Large Millimeter Telescope (LMT). We will conclude this presentation with a summary of future LMT observations that will trace the evolution of obscured starformation in the dynamic environments towards a significant sample of intermediate and high-z powerful AGN with greater sensitivity and spatial resolution.

In vitro and in vivo studies of biodegradable fine grained AZ31 magnesium alloy produced by equal channel angular pressing.

PubMed

Ratna Sunil, B; Sampath Kumar, T S; Chakkingal, Uday; Nandakumar, V; Doble, Mukesh; Devi Prasad, V; Raghunath, M

2016-02-01

The objective of the present work is to investigate the role of different grain sizes produced by equal channel angular pressing (ECAP) on the degradation behavior of magnesium alloy using in vitro and in vivo studies. Commercially available AZ31 magnesium alloy was selected and processed by ECAP at 300°C for up to four passes using route Bc. Grain refinement from a starting size of 46μm to a grain size distribution of 1-5μm was successfully achieved after the 4th pass. Wettability of ECAPed samples assessed by contact angle measurements was found to increase due to the fine grain structure. In vitro degradation and bioactivity of the samples studied by immersing in super saturated simulated body fluid (SBF 5×) showed rapid mineralization within 24h due to the increased wettability in fine grained AZ31 Mg alloy. Corrosion behavior of the samples assessed by weight loss and electrochemical tests conducted in SBF 5× clearly showed the prominent role of enhanced mineral deposition on ECAPed AZ31 Mg in controlling the abnormal degradation. Cytotoxicity studies by MTT colorimetric assay showed that all the samples are viable. Additionally, cell adhesion was excellent for ECAPed samples particularly for the 3rd and 4th pass samples. In vivo experiments conducted using New Zealand White rabbits clearly showed lower degradation rate for ECAPed sample compared with annealed AZ31 Mg alloy and all the samples showed biocompatibility and no health abnormalities were noticed in the animals after 60days of in vivo studies. These results suggest that the grain size plays an important role in degradation management of magnesium alloys and ECAP technique can be adopted to achieve fine grain structures for developing degradable magnesium alloys for biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

75 FR 11554 - Notice of Intent to Repatriate Cultural Items: Museum of Northern Arizona, Flagstaff, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-11

... continue to be used by traditional Navajo religious practitioners. Based on the sacred esoteric knowledge... Northern Arizona, Flagstaff, AZ, that meet the definitions of ``sacred objects'' and ``objects of cultural... the area of Farmington, NM. The 29 cultural items are 4 watercolors of sacred Navajo Yei figures and...

Mineral Mapping Using AVIRIS Data at Ray Mine, AZ

NASA Technical Reports Server (NTRS)

McCubbin, Ian; Lang, Harold; Green, Robert O.; Roberts, Dar

1998-01-01

Imaging Spectroscopy enables the identification and mapping of surface mineralogy over large areas. This study focused on assessing the utility of Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) data for environmental impact analysis over the Environmental Protection Agency's (EPA) high priority Superfund site Ray Mine, AZ. Using the Spectral Angle Mapper (SAM) algorithm to analyze AVIRIS data makes it possible to map surface materials that are indicative of acid generating minerals. The improved performance of the AVIRIS sensor since 1996 provides data with sufficient signal to noise ratio to characterize up to 8 image endmembers. Specifically we employed SAM to map minerals associated with mine generated acid waste, namely jarositc, goethite, and hematite, in the presence of a complex mineralogical background.

Torsional and axial damping properties of the AZ31B-F magnesium alloy

NASA Astrophysics Data System (ADS)

Anes, V.; Lage, Y. E.; Vieira, M.; Maia, N. M. M.; Freitas, M.; Reis, L.

2016-10-01

Damping properties for the AZ31B-F magnesium alloy were evaluated for pure axial and pure shear loading conditions at room temperature. Hysteretic damping results were measured through stress-strain controlled tests. Moreover, the magnesium alloy viscous damping was measured with frequency response functions and free vibration decay, both results were obtained by experiments. The axial and shear damping ratio (ASDR) has been identified and described, specifically for free vibration conditions.

In vitro degradation behavior and cytocompatibility of biodegradable AZ31 alloy with PEO/HT composite coating.

PubMed

Tian, Peng; Liu, Xuanyong; Ding, Chuanxian

2015-04-01

Biodegradable magnesium-based implants have attracted much attention recently in orthopedic applications because of their good mechanical properties and biocompatibility. However, their rapid degradation in vivo will not only reduce their mechanical strength, but also induce some side effects, such as local alkalization and gas cavity, which may lead to a failure of the implant. In this work, a hydroxyapatite (HA) layer was prepared on plasma electrolytic oxidization (PEO) coating by hydrothermal treatment (HT) to fabricate a PEO/HT composite coating on biodegradable AZ31 alloy. The in vitro degradation behaviors of all samples were evaluated in simulated body fluid (SBF) and their surface cytocompatibility was also investigated by evaluating the adhesion and proliferation of osteoblast cells (MC3T3-E1). The results showed that the HA layer consisted of a dense inner layer and a needle-like outer layer, which successfully sealed the PEO coating. The in vitro degradation tests showed that the PEO/HT composite coating improved the corrosion resistance of AZ31 alloy in SBF, presenting nearly no severe local alkalization and hydrogen evolution. The lasting corrosion resistance of the PEO/HT composite coating may attribute to the new hydroxyapatite formation during the degradation process. Moreover, compared with AZ31 alloy and PEO coating, PEO/HT composite coating was more suitable for cells adhesion and proliferation, indicating improved surface cytocompatibility. The results show that the PEO/HT composite coating is promising as protective coating on biodegradable magnesium-based implants to enhance their corrosion resistance as well as improve their surface cytocompatibility for orthopedic applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Corrosion mechanism and model of pulsed DC microarc oxidation treated AZ31 alloy in simulated body fluid

NASA Astrophysics Data System (ADS)

Gu, Yanhong; Chen, Cheng-fu; Bandopadhyay, Sukumar; Ning, Chengyun; Zhang, Yongjun; Guo, Yuanjun

2012-06-01

This paper addresses the effect of pulse frequency on the corrosion behavior of microarc oxidation (MAO) coatings on AZ31 Mg alloys in simulated body fluid (SBF). The MAO coatings were deposited by a pulsed DC mode at four different pulse frequencies of 300 Hz, 500 Hz, 1000 Hz and 3000 Hz with a constant pulse ratio. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests were used for corrosion rate and electrochemical impedance evaluation. The corroded surfaces were examined by X-ray diffraction (XRD), X-ray fluorescence (XRF) and optical microscopy. All the results exhibited that the corrosion resistance of MAO coating produced at 3000 Hz is superior among the four frequencies used. The XRD spectra showed that the corrosion products contain hydroxyapatite, brucite and quintinite. A model for corrosion mechanism and corrosion process of the MAO coating on AZ31 Mg alloy in the SBF is proposed.

Improving Tensile and Compressive Properties of an Extruded AZ91 Rod by the Combined Use of Torsion Deformation and Aging Treatment

PubMed Central

Song, Bo; Wang, Chunpeng; Guo, Ning; Pan, Hucheng; Xin, Renlong

2017-01-01

In this study, AZ91 magnesium alloy rods were used to investigate the effects of torsion deformation on microstructure and subsequent aging behavior. Extruded AZ91 rod has a uniform microstructure and typical fiber texture. Torsion deformation can generate a gradient microstructure on the cross-section of the rod. After torsion, from the center to the edge in the cross-section of the rod, both stored dislocations and area fraction of {10-12} twins gradually increase, and the basal pole of the texture tends to rotate in the ED direction. Direct aging usually generates coarse discontinuous precipitates and fine continuous precipitates simultaneously. Both twin structures and dislocations via torsion deformation can be effective microstructures for the nucleation of continuous precipitates during subsequent aging. Thus, aging after torsion can promote continuous precipitation and generate gradient precipitation characteristics. Both aging treatment and torsion deformation can reduce yield asymmetry, and torsion deformation enhances the aging hardening effect by promoting continuous precipitation. Therefore, combined use of torsion deformation and aging treatment can effectively enhance the yield strength and almost eliminate the yield asymmetry of the present extruded AZ91 rod. Finally, the relevant mechanisms are discussed. PMID:28772638

Microstructural Effects on the Spall Properties of ECAE-Processed AZ31B Magnesium Alloy

DTIC Science & Technology

2016-10-01

ARL-RP-0580 ● OCT 2016 US Army Research Laboratory Microstructural Effects on the Spall Properties of ECAE-Processed AZ31B...not to be construed as an official Department of the Army position unless so designated by other authorized documents. Citation of manufacturer’s...return it to the originator. ARL-RP-0580 ● OCT 2016 US Army Research Laboratory Microstructural Effects on the Spall Properties

78 FR 14571 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-06

... Camp Verde The Honorable Bob Town Clerk's Office, December 31, 2012 040131 1277). (12-09-1430P). Burnside, Mayor, Town of 473 South Main Camp Verde, 473 South Street, Room 102, Main Street, Suite 102, Camp Verde, AZ Camp Verde, AZ 86322. 86322. California: San Diego (FEMA Docket No.: B- City of...

Analysis of fish bile with HPLC — fluorescence to determine environmental exposure to benzo(a)pyrene

USGS Publications Warehouse

Johnston, Eric P.; Baumann, Paul C.

1989-01-01

Brown bullhead from the Black River, Ohio, have a high incidence of liver neoplasia which is associated with elevated concentrations of polynuclear aromatic hydrocarbons (PAHs) in the sediment. We evaluated the use of biliary concentrations of benzo(a)pyrene [B(a)P] equivalents as a means for determining PAH exposure. Bile was collected from 16 brown bullheads and 8 common carp taken from each of two Lake Erie tributaries in Ohio, the industrialized Black River and the non-industrialized Old Woman Creek. Hatchery bullhead (n = 8) were used to determine base levels of PAHs. A high performance liquid chromatography (HPLC) — fluorescence technique was used to determine the concentration of B(a)P equivalents in the bile samples. The area of all peaks fluorescing at 380/430 nm was summed to give a single value for B(a)P equivalents in each sample. Concentrations of B(a)P equivalents generally reflected concentrations of PAH in sediment where fish were collected. Bile taken from Black River carp contained the highest concentration of B(a)P equivalents and was significantly different from all other groups. The value obtained for Black River bullhead was also high and was found to be significantly different from hatchery bullhead. B(a)P equivalents varied between carp and bullhead from the same habitat possibly because of differing food habits or metabolic pathways. However, our results indicate that relative levels of B(a)P equivalents in the bile of fish correspond well to B(a)P levels in sediment and may offer a means of determining environmental exposure of fish to the parent compound.

Influence of Tension-Compression Asymmetry on the Mechanical Behavior of AZ31B Magnesium Alloy Sheets in Bending

NASA Astrophysics Data System (ADS)

Zhou, Ping; Beeh, Elmar; Friedrich, Horst E.

2016-03-01

Magnesium alloys are promising materials for lightweight design in the automotive industry due to their high strength-to-mass ratio. This study aims to study the influence of tension-compression asymmetry on the radius of curvature and energy absorption capacity of AZ31B-O magnesium alloy sheets in bending. The mechanical properties were characterized using tension, compression, and three-point bending tests. The material exhibits significant tension-compression asymmetry in terms of strength and strain hardening rate due to extension twinning in compression. The compressive yield strength is much lower than the tensile yield strength, while the strain hardening rate is much higher in compression. Furthermore, the tension-compression asymmetry in terms of r value (Lankford value) was also observed. The r value in tension is much higher than that in compression. The bending results indicate that the AZ31B-O sheet can outperform steel and aluminum sheets in terms of specific energy absorption in bending mainly due to its low density. In addition, the AZ31B-O sheet was deformed with a larger radius of curvature than the steel and aluminum sheets, which brings a benefit to energy absorption capacity. Finally, finite element simulation for three-point bending was performed using LS-DYNA and the results confirmed that the larger radius of curvature of a magnesium specimen is mainly attributed to the high strain hardening rate in compression.

Electrochemical Performance Estimation of Anodized AZ31B Magnesium Alloy as Function of Change in the Current Density

NASA Astrophysics Data System (ADS)

Girón, L.; Aperador, W.; Tirado, L.; Franco, F.; Caicedo, J. C.

2017-08-01

The anodized AZ31B magnesium alloys were synthesized via electrodeposition processes. The aim of this work was to determine the electrochemical behavior of magnesium alloys by using anodized alloys as a protective coating. The anodized alloys were characterized by x-ray diffraction, exhibiting the crystallography orientation for Mg and MgO phases. The x-ray photoelectron spectroscopy was used to determine the chemical composition of anodized magnesium alloys. By using electrochemical impedance spectroscopy and Tafel curves, it was possible to estimate the electrochemical behavior of anodized AZ31B magnesium alloys in Hank's balanced salt solution (HBSS). Scanning electron microscopy was performed to analyze chemical changes and morphological surface changes on anodized Mg alloys due to the reaction in HBSS/anodized magnesium surface interface. Electrochemical behavior in HBSS indicates that the coatings may be a promising material for biomedical industry.

Efficacy of topical azelaic acid (AzA) gel 15% plus oral doxycycline 40 mg versus metronidazole gel 1% plus oral doxycycline 40 mg in mild-to-moderate papulopustular rosacea.

PubMed

Del Rosso, James Q; Bruce, Suzanne; Jarratt, Michael; Menter, Alan; Staedtler, Gerald

2010-06-01

Rosacea is a leading reason why people seek the care of a dermatologist, accounting for nearly 7 million office visits annually. Pharmacologic treatments include both topical and oral medications, which are increasingly being used in combination, especially at the outset of therapy. This exploratory study assesses the safety, effectiveness and speed of onset of two common topical agents for the treatment of rosacea--azelaic acid gel (AzA) 15% and metronidazole gel 1%--used in conjunction with anti-inflammatory dose doxycycline (40 mg once daily). Men and women (n = 207) with mild-to-moderate papulopustular rosacea were enrolled and randomized to receive either AzA gel 15% twice daily plus doxycycline 40 mg once daily (AzA group) or metronidazole gel 1% once daily plus doxycycline 40 mg once daily (Metro group) for 12 weeks. Both regimens were safe, efficacious and well tolerated. Efficacy parameters revealed a possible trend toward greater and earlier benefit with the AzA-based regimen than with the metronidazole-based regimen. These findings warrant further investigation in a sufficiently powered study.

Corrosion resistance of titanium ion implanted AZ91 magnesium alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Chenglong; Xin Yunchang; Tian Xiubo

2007-03-15

Degradable metal alloys constitute a new class of materials for load-bearing biomedical implants. Owing to their good mechanical properties and biocompatibility, magnesium alloys are promising in degradable prosthetic implants. The objective of this study is to improve the corrosion behavior of surgical AZ91 magnesium alloy by titanium ion implantation. The surface characteristics of the ion implanted layer in the magnesium alloys are examined. The authors' results disclose that an intermixed layer is produced and the surface oxidized films are mainly composed of titanium oxide with a lesser amount of magnesium oxide. X-ray photoelectron spectroscopy reveals that the oxide has threemore » layers. The outer layer which is 10 nm thick is mainly composed of MgO and TiO{sub 2} with some Mg(OH){sub 2}. The middle layer that is 50 nm thick comprises predominantly TiO{sub 2} and MgO with minor contributions from MgAl{sub 2}O{sub 4} and TiO. The third layer from the surface is rich in metallic Mg, Ti, Al, and Ti{sub 3}Al. The effects of Ti ion implantation on the corrosion resistance and electrochemical behavior of the magnesium alloys are investigated in simulated body fluids at 37{+-}1 deg. C using electrochemical impedance spectroscopy and open circuit potential techniques. Compared to the unimplanted AZ91 alloy, titanium ion implantation significantly shifts the open circuit potential (OCP) to a more positive potential and improves the corrosion resistance at OCP. This phenomenon can be ascribed to the more compact surface oxide film, enhanced reoxidation on the implanted surface, as well as the increased {beta}-Mg{sub 12}Al{sub 17} phase.« less

Laser surface modification of AZ31B Mg alloy for bio-wettability.

PubMed

Ho, Yee-Hsien; Vora, Hitesh D; Dahotre, Narendra B

2015-02-01

Magnesium alloys are the potential degradable materials for load-bearing implant application due to their comparable mechanical properties to human bone, excellent bioactivity, and in vivo non-toxicity. However, for a successful load-bearing implant, the surface of bio-implant must allow protein absorption and layer formation under physiological environment that can assist the cell/osteoblast growth. In this regard, surface wettability of bio-implant plays a key role to dictate the quantity of protein absorption. In light of this, the main objective of the present study was to produce favorable bio-wettability condition of AZ31B Mg alloy bio-implant surface via laser surface modification technique under various laser processing conditions. In the present efforts, the influence of laser surface modification on AZ31B Mg alloy surface on resultant bio-wettability was investigated via contact-angle measurements and the co-relationships among microstructure (grain size), surface roughness, surface energy, and surface chemical composition were established. In addition, the laser surface modification technique was simulated by computational (thermal) model to facilitate the prediction of temperature and its resultant cooling/solidification rates under various laser processing conditions for correlating with their corresponding composition and phase evolution. These predicted thermal properties were later used to correlate with the corresponding microstructure, chemical composition, and phase evolution via experimental analyses (X-ray diffractometer, scanning electron microscope, energy-dispersive spectroscopy). © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Nematode Community Response to Green Infrastructure Design in a Semiarid City.

PubMed

Pavao-Zuckerman, Mitchell A; Sookhdeo, Christine

2017-05-01

Urbanization affects ecosystem function and environmental quality through shifts in ecosystem fluxes that are brought on by features of the built environment. Green infrastructure (GI) has been suggested as a best management practice (BMP) to address urban hydrologic and ecological impacts of the built environment, but GI practice has only been studied from a limited set of climatic conditions and disciplinary approaches. Here, we evaluate GI features in a semiarid city from the perspective of soil ecology through the application of soil nematode community analysis. This study was conducted to investigate soil ecological interactions in small-scale GI as a means of assessing curb-cut rain garden basin design in a semiarid city. We looked at the choice of mulching approaches (organic vs. rock) and how this design choice affects the soil ecology of rain basins in Tucson, AZ. We sampled soils during the monsoon rain season and assessed the soil nematode community as a bioindicator of soil quality and biogeochemical processes. We found that the use of organic mulch in GI basins promotes enhanced soil organic matter contents and larger nematode populations. Nematode community indices point to enhanced food web structure in streetscape rain garden basins that are mulched with organic material. Results from this study suggest that soil management practices for GI can help promote ecological interactions and ecosystem services in urban ecosystems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

76 FR 15936 - Designation for the Owensboro, KY; Bloomington, IL; Iowa Falls, IA; Casa Grande, AZ; Fargo, ND...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-22

... DEPARTMENT OF AGRICULTURE Grain Inspection, Packers and Stockyards Administration Designation for the Owensboro, KY; Bloomington, IL; Iowa Falls, IA; Casa Grande, AZ; Fargo, ND; Grand Forks, ND; and Plainview, TX Areas AGENCY: Grain Inspection, Packers and Stockyards Administration, USDA. ACTION: Notice...

Arsenic Removal from Drinking Water by Adsorptive Media USEPA Demonstration Project at Rimrock AZ Final Performance Evaluation Report

EPA Science Inventory

This report documents the activities performed during and the results obtained from the arsenic removal treatment technology demonstration project at the Arizona Water Company (AWC) facility in Rimrock, AZ. The objectives of the project were to evaluate: 1) the effectiveness of ...

77 FR 75144 - Foreign-Trade Zone 277-Western Maricopa County, AZ; Application for Expansion; (New Magnet Site...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-12-19

... Maricopa County, AZ; Application for Expansion; (New Magnet Site) Under Alternative Site Framework An... additional new magnet sites in western Maricopa County, Arizona and request usage-driven designation for an..., Arizona. The current zone project includes the following magnet sites: Site 1 (230.25 acres)--within the...

Best Practices Case Study: John Wesley Miller Companies - Armory Park Del Sol, Tucson, AZ

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

Case study of John Wesley Miller Companies, who built two net zero energy homes plus 97 other solar homes in Tucson, AZ. Masonry block walls with rigid foam exterior sheathing, rigid foam over the roof deck plus R-38 in the attic, ducts in conditioned space, 4.2 kW and 5.7 kW photovoltaics and solar water heating yielded HERS scores of 0 on the two homes.

The Effect of Friction Stir Processing on Microstructure and Tensile Behavior of Thixomolded AZ91 Magnesium Alloy

NASA Astrophysics Data System (ADS)

Mansoor, B.; Decker, R. F.; Kulkarni, S.; LeBeau, S. E.; Khraisheh, M. K.

Friction Stir Processing (FSP) to partial sheet thickness can be utilized to engineer unique microstructures in metallic alloys. These composite microstructures consist of three distinct layers associated with stirred, transition and core micro structural regions. The stirred region is of particular interest where severe plastic deformation imparted by the rotating and translating FSP tool under frictional heat leads to grain refinement down to 1 urn grain size. In this work, partial depth penetration into thixomolded AZ91 Mg plate from the top and bottom surfaces by friction stir processing is explored. Furthermore, low temperature aging treatments are applied to the processed material. The present results with AZ91 Mg show that FSP processed material exhibits higher strength (> 300 MPa), and improvement in ductility (> 7 % tensile elongation). It is found that in addition to Hall-Petch strengthening produced by 1 um grain size in the stirred region, the enhanced strength levels and ductility are strongly influenced by dispersoids of the intermetallic precipitates found in this alloy.

FINAL REPORT DM1200 TESTS WITH AZ 101 HLW SIMULANTS VSL-03R3800-4 REV 0 2/17/04

DOE Office of Scientific and Technical Information (OSTI.GOV)

KRUGER AA; MATLACK KS; BARDAKCI T

2011-12-29

This report documents melter and off-gas performance results obtained on the DM 1200 HLW Pilot Melter during processing of simulated HLW AZ-101 feed. The principal objectives of the DM1200 melter testing were to determine the achievable glass production rates for simulated HLW AZ-101 feed; determine the effect of bubbling rate and feed solids content on production rate; characterize melter off-gas emissions; characterize the performance of the prototypical off-gas system components as well as their integrated performance; characterize the feed, glass product, and off-gas effluents; and to perform pre- and post-test inspections of system components. The test objectives (including test successmore » criteria), along with how they were met, are outlined in a table.« less

AZ-101 Mixer Pump Demonstration Data Acquisition System and Gamma Cart Data Acquisition Control System Software Configuration Management Plan

DOE Office of Scientific and Technical Information (OSTI.GOV)

WHITE, D.A.

1999-12-29

This Software Configuration Management Plan (SCMP) provides the instructions for change control of the AZ1101 Mixer Pump Demonstration Data Acquisition System (DAS) and the Sludge Mobilization Cart (Gamma Cart) Data Acquisition and Control System (DACS).

The Ballistic and Corrosion Evaluation of Magnesium Elektron E675 vs. Baseline Magnesium Alloy AZ31B and Aluminum Alloy 5083 for Armor Applications

DTIC Science & Technology

2011-06-01

critical property in reducing the plastic failure of the material. The ductility is marginally better than Mg AZ31B. 2 Table 1. Chemical...composition (%) of metal alloys. Element (%)/Alloy CPMg 9980B AZ31B-H24 AA5083-H131 Aluminum — 2.5–3.5 REM Manganese 0.10 max 0.2–1.0 0.40‒1.0 Zinc — 0.6...This trend was attributed to the lack of ductility in E675 compared to 5083, which reduced energy dissipation. Visual analysis of the Mg E675

Darkening effect on AZ31B magnesium alloy surface induced by nanosecond pulse Nd:YAG laser

NASA Astrophysics Data System (ADS)

Guan, Y. C.; Zhou, W.; Zheng, H. Y.; Li, Z. L.

2013-09-01

Permanent darkening effect was achieved on surface of AZ31B Mg alloy irradiated with nanosecond pulse Nd:YAG laser, and special attention was made to examine how surface structure as well as oxidation affect the darkening effect. Experiments were carried out to characterize morphological evolution and chemical composition of the irradiated areas by optical reflection spectrometer, Talysurf surface profiler, SEM, EDS, and XPS. The darkening effect was found to be occurred at the surface under high laser energy. Optical spectra showed that the induced darkening surface was uniform over the spectral range from 200 nm to 1100 nm. SEM and surface profiler showed that surface morphology of darkening areas consisted of large number of micron scale cauliflower-like clusters and protruding particles. EDS and XPS showed that compared to non-irradiated area, oxygen content at the darkening areas increased significantly. It was proposed a mechanism that involved trapping of light in the surface morphology and chemistry variation of irradiated areas to explain the laser-induced darkening effect on AZ31B Mg alloy.

Electrophoretic deposition of nanostructured hydroxyapatite coating on AZ91 magnesium alloy implants with different surface treatments

NASA Astrophysics Data System (ADS)

Rojaee, Ramin; Fathi, Mohammadhossein; Raeissi, Keyvan

2013-11-01

Bio-absorbable magnesium (Mg) based alloys have been introduced as innovative orthopedic implants during recent years. It has been specified that rapid degradation of Mg based alloys in physiological environment should be restrained in order to be utilized in orthopedic trauma fixation and vascular intervention. In this developing field of healthcare materials, micro-arc oxidation (MAO), and MgF2 conversion coating were exploited as surface pre-treatment of AZ91 magnesium alloy to generate a nanostructured hydroxyapatite (n-HAp) coating via electrophoretic deposition (EPD) method. X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), and transmission electron microscopy (TEM) techniques were used to characterize the obtained powder and coatings. The potentiodynamic polarization tests were carried out to evaluate the corrosion behavior of the coated and uncoated specimens, and in vitro bioactivity evaluation were performed in simulated body fluid. Results revealed that the MAO/n-HAp coated AZ91 Mg alloy samples with a rough topography and lower corrosion current density leads to a lower Mg degradation rate accompanied by high bioactivity.

ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA, USEPA DEMONSTRATION PROJECT AT RIMROCK, AZ, SIX-MONTH EVALUATION REPORT

EPA Science Inventory

This report documents the activities performed during and the results obtained from the first six months of the arsenic removal treatment technology demonstration project at Rimrock, AZ. The objectives of the project are to evaluate the effectiveness of AdEdge Arsenic Package Uni...

Experimental investigation of anisotropy evolution of AZ31 magnesium alloy sheets under tensile loading

NASA Astrophysics Data System (ADS)

Tari, D. Ghaffari; Worswick, M. J.

2011-05-01

Increasing demand for lighter final products has created new opportunities for the application of new light weight materials. Due to high strength to density ratio and good magnetic resistance properties, magnesium alloys are good candidates to replace steel and aluminum for same application. However, limited numbers of active slip deformation mechanisms, result in a decreased formability at room temperature. Furthermore, wrought magnesium alloys have an initial crystallographic texture, remained from the prior rolling operations, which makes them highly anisotropic. In this paper, tensile tests are performed at room temperature and 200° C at different strain rates and orientations relative to the rolling direction, including rolling, 30°, 45°, 60° and transverse orientation. The strain rates adopted for these experiments varied from 0.001 to 1.0. The testing results show the effect of temperature on the strain rate sensitivity of AZ31 sheets. The extent of deformation is continuously recorded using two separate high temperature extensometers. The results of testing show an increase in the r-values with the plastic deformation. The strain rate sensitivity of AZ31 increased as the temperature was elevated. At higher strain rates the measured r-values are larger and the slope of its evolution with the plastic strain is steeper.

Chemical Characterization of an Envelope B/D Sample from Hanford Tank 241-AZ-102

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hay, M.S.

2000-08-23

A sample from Hanford waste tank 241-AZ-102 was received at the Savannah River Technology Center (SRTC) and chemically characterized. The sample containing supernate and a small amount of sludge solids was analyzed as-received. The filtered supernatant liquid, the total dried solids of the sample, and the washed insoluble solids obtained from filtration of the sample were analyzed. A mass balance calculation of the three fractions of the sample analyzed indicate the analytical results appear relatively self-consistent for major components of the sample. However, some inconsistency was observed between results were more than one method of determination was employed and formore » species present in low concentrations. The actinides isotopes, plutonium, americium, and curium, present analytical challenges due to the low concentration of these species and the potential for introduction of small amounts of contamination during sampling handling resulting in large uncertainties. A direct comparison to previous analyses of material from tank 241-AZ-102 showed good agreement with the filtered supernatant liquid. However, the comparison of solids data showed poor agreement. The poor agreement shown between the current results for the solids samples and previous analyses most likely results from the uncertainties associated with obtaining small solids samples from a large non-homogenized waste tank.« less

A cross-shear deformation for optimizing the strength and ductility of AZ31 magnesium alloys

PubMed Central

Hamad, Kotiba; Ko, Young Gun

2016-01-01

Magnesium alloys have recently attracted great interest due their lightweight and high specific strength. However, because of their hexagonal close-packed structure, they have few active slip systems, resulting in poor ductility and high mechanical anisotropy at room temperature. In the present work, we used a cross-shear deformation imposed by a differential speed rolling (DSR) technique to improve the room temperature strength and ductility of AZ31 magnesium alloy sheets. To introduce the cross-shear deformation, the sheets were rotated 180° around their longitudinal axis between the adjacent passes of DSR. The sheets of the AZ31 alloy subjected to the cross-shear deformation showed a uniform fine microstructure (1.2 ± 0.1 μm) with weak basal textures. The fabricated sheets showed a simultaneous high ultimate tensile strength and elongation-to-failure, i.e., ~333 MPa and ~21%, respectively. These were explained based on the structural features evolved due to the cross-shear deformation by DSR. The high strength was attributed to the uniform fine microstructure, whereas the high ductility was explained based on the basal texture weakening. PMID:27406685

Précipitation sélective de cations métalliques au moyen d'acide azélaïque issu de l'oxydation de l'acide oléique

NASA Astrophysics Data System (ADS)

Zimmermann, F.; Meux, E.; Oget, N.; Lecuire, J. M.; Mieloszynski, J. L.

2004-12-01

Actuellement, les métaux présents dans les effluents liquides industriels sont précipités sous forme d'hydroxydes métalliques par ajout de lait de chaux. Les boues obtenues sont dirigées vers des centres de stockage de déchets ultimes sans possibilité de valorisation. Cette étude propose comme alternative au traitement actuel, une précipitation sélective par des réactifs qui peuvent être préparés à partir d'acides carboxyliques résultant de l'oxydation de l'acide oléique présent dans les huiles végétales. Cette publication présente dans un premier temps l'oxydation de l'acide oléique par le système oxydant NaIO4/RuO4 pour l'obtention de deux acides carboxyliques. Le rendement de l'oxydation de l'acide oléique est de 100% avec production des acides pélargonïque et azélaïque qui sont facilement purifiés par recristallisation dans l’eau. Dans un deuxième temps, cette étude présente la caractérisation de différents azélates métalliques. La détermination de leur stœchiométrie conduit à des composés de type MAz pour les cations divalents et M2Az3 pour les trivalents. Des mesures de solubilités ont été réalisées pour les azélates de Fe(III), Pb(II), Zn(II), Cu(II), Ni(II) et Ca(II). La gamme de solubilité s'étend de 1,17.10-2 M pour CaAz à 1,58.10-6 M pour Fe2Az3.

31 CFR 332.12 - Fiscal agents.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 332.12 Section 332.12 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... City, 925 Grand Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas City, St. Louis AK, AR, AZ...

An AzTEC 1.1mm survey of the GOODS-N field - II. Multiwavelength identifications and redshift distribution

NASA Astrophysics Data System (ADS)

Chapin, Edward L.; Pope, Alexandra; Scott, Douglas; Aretxaga, Itziar; Austermann, Jason E.; Chary, Ranga-Ram; Coppin, Kristen; Halpern, Mark; Hughes, David H.; Lowenthal, James D.; Morrison, Glenn E.; Perera, Thushara A.; Scott, Kimberly S.; Wilson, Grant W.; Yun, Min S.

2009-10-01

We present results from a multiwavelength study of 29 sources (false detection probabilities <5 per cent) from a survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field at 1.1mm using the Astronomical Thermal Emission Camera (AzTEC). Comparing with existing 850μm Submillimetre Common-User Bolometer Array (SCUBA) studies in the field, we examine differences in the source populations selected at the two wavelengths. The AzTEC observations uniformly cover the entire survey field to a 1σ depth of ~1mJy. Searching deep 1.4GHz Very Large Array (VLA) and Spitzer 3-24μm catalogues, we identify robust counterparts for 21 1.1mm sources, and tentative associations for the remaining objects. The redshift distribution of AzTEC sources is inferred from available spectroscopic and photometric redshifts. We find a median redshift of z = 2.7, somewhat higher than z = 2.0 for 850μm selected sources in the same field, and our lowest redshift identification lies at a spectroscopic redshift z = 1.1460. We measure the 850μm to 1.1mm colour of our sources and do not find evidence for `850μm dropouts', which can be explained by the low signal-to-noise ratio of the observations. We also combine these observed colours with spectroscopic redshifts to derive the range of dust temperatures T, and dust emissivity indices β for the sample, concluding that existing estimates T ~ 30K and β ~ 1.75 are consistent with these new data.

Influence of shot peening on corrosion properties of biocompatible magnesium alloy AZ31 coated by dicalcium phosphate dihydrate (DCPD).

PubMed

Mhaede, Mansour; Pastorek, Filip; Hadzima, Branislav

2014-06-01

Magnesium alloys are promising materials for biomedical applications because of many outstanding properties like biodegradation, bioactivity and their specific density and Young's modulus are closer to bone than the commonly used metallic implant materials. Unfortunately their fatigue properties and low corrosion resistance negatively influenced their application possibilities in the field of biomedicine. These problems could be diminished through appropriate surface treatments. This study evaluates the influence of a surface pre-treatment by shot peening and shot peening+coating on the corrosion properties of magnesium alloy AZ31. The dicalcium phosphate dihydrate coating (DCPD) was electrochemically deposited in a solution containing 0.1M Ca(NO3)2, 0.06M NH4H2PO4 and 10mL/L of H2O2. The effect of shot peening on the surface properties of magnesium alloy was evaluated by microhardness and surface roughness measurements. The influence of the shot peening and dicalcium phosphate dihydrate layer on the electrochemical characteristics of AZ31 magnesium alloy was evaluated by potentiodynamic measurements and electrochemical impedance spectroscopy in 0.9% NaCl solution at a temperature of 22±1°C. The obtained results were analyzed by the Tafel-extrapolation method and equivalent circuit method. The results showed that the application of shot peening process followed by DCPD coating improves the properties of the AZ31 surface from corrosion and mechanical point of view. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of 241-AZ tank farm supporting phase 1 privatization waste feed delivery

DOE Office of Scientific and Technical Information (OSTI.GOV)

CARLSON, A.B.

1998-11-19

This evaluation is one in a series of evaluations determining the process needs and assessing the adequacy of existing and planned equipment in meeting those needs at various double-shell tank farms in support of Phase 1 privatization. A number of tank-to-tank transfers and waste preparation activities are needed to process and feed waste to the private contractor in support of Phase 1 privatization. The scope of this evaluation is limited to process needs associated with 241-AZ tank farm during the Phase 1 privatization.

78 FR 34403 - Notice of Availability of the Record of Decision for the Quartzsite Solar Energy Project, AZ

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-07

...: http://www.blm.gov/az/st/en/prog/energy/solar/quartzsite_solar_energy.html . FOR FURTHER INFORMATION... . Persons who use a telecommunications device for the deaf (TDD) may call the Federal Information Relay.... You will receive a reply during normal business hours. SUPPLEMENTARY INFORMATION: Quartzsite Solar...

A historical perspective on the "fish tumors or other deformities" beneficial use impairment at Great Lakes Areas of Concern

USGS Publications Warehouse

Rafferty, S.D.; Blazer, V.S.; Pinkney, A.E.; Grazio, J.L.; Obert, E.C.; Boughton, L.

2009-01-01

The Great Lakes Water Quality Agreement defines Areas of Concern as geographic areas that fail to meet the general or specific objectives of the agreement where such failure has caused or is likely to cause impairment of beneficial use of the area's ability to support aquatic life. One of the beneficial use impairments, fish tumors or other deformities, is defined by the International Joint Commission to occur when the incidence rate of fish tumors and other deformities exceeds rates at unimpacted or control sites, or when survey data confirm the presence of neoplastic or preneoplastic liver tumors in bullhead or suckers. Brown bullhead, a benthic species with a limited home range, have frequently been used as indicator species in U.S. Areas of Concern. While there is strong field evidence for an association between PAH exposure and hepatic neoplasia in brown bullhead, laboratory investigations would strengthen the association. There is less evidence linking specific classes of chemicals in the environment to orocutaneous neoplasia in brown bullhead. Studies on orocutaneous neoplasia of brown bullhead should focus on assessing the presence or absence of viruses and on epidermal exposure to specific chemicals and chemical mixtures. Lastly, the effects of covariates such as length, age, and gender on the prevalence of liver and skin neoplasms should be investigated. This paper reviews the state of science on the fish tumors or other deformities beneficial use impairment. Subsequent papers address specific issues related to this impairment and provide recommendations for standardized criteria.

Physical properties of the extreme Centaur and super-comet candidate 2013 AZ60

NASA Astrophysics Data System (ADS)

Pál, A.; Kiss, Cs.; Horner, J.; Szakáts, R.; Vilenius, E.; Müller, Th. G.; Acosta-Pulido, J.; Licandro, J.; Cabrera-Lavers, A.; Sárneczky, K.; Szabó, Gy. M.; Thirouin, A.; Sipőcz, B.; Dózsa, Á.; Duffard, R.

2015-11-01

We present estimates of the basic physical properties including size and albedo of the extreme Centaur 2013 AZ60. These properties have been derived from optical and thermal infrared measurements. Our optical measurements revealed a probable full period of ≈9.4 h with a shallow amplitude of 4.5%. By combining optical brightness information and thermal emission data, we are able to derive a diameter of 62.3 ± 5.3 km and a geometric albedo of 2.9%, which corresponds to an extremely dark surface. Additionally, our finding of ≳50 Jm-2 K-1 s- 1/2 for the thermal inertia is also remarkable for objects in such a distance. The results of dynamical simulations yield an unstable orbit, with a 50% probability that the target will be ejected from the solar system within 700 000 yr. The current orbit of this object and its instability could imply a pristine cometary surface. This possibility agrees with the observed low geometric albedo and red photometric colour indices for the object, which match the surface of a dormant comet well, as would be expected for a long-period cometary body approaching perihelion. Although it was approaching ever closer to the Sun, however, the object exhibited star-like profiles in each of our observations, lacking any sign of cometary activity. According to the albedo, 2013 AZ60 is a candidate for the darkest body among the known trans-Neptunian objects.

Degraded and osteogenic properties of coated magnesium alloy AZ31; an experimental study.

PubMed

Zhuang, Jinpeng; Jing, Yongbin; Wang, Yaming; Zhang, Jinghuai; Xie, Huanxin; Yan, Jinglong

2016-03-14

Degraded and osteogenic property of coated magnesium alloy was evaluated for the fracture fixation in rabbits. Magnesium alloy AZ31 with a different coating thickness by microarc oxidation was used, and the bilateral radial fracture model was created by the bite bone clamp. Thirty-six New Zealand white rabbits in weight of 2.5~3.0 kg were randomly divided into A, B, and C groups at four time points and other 3 rabbits as the control group without magnesium alloy. Coated magnesium alloy AZ31 was implanted on the fracture and fixed with silk thread. Indexes such as general observation, histology, X-ray, hematology, and mechanical properties were observed and detected at 2nd, 4th, 8th, and 12th week after implantation. Fracture in each rabbit was healed at 12th week after implantation. Among the three groups, the best results of general observation, histology, and X-ray appeared in A group without coating. However, A group showed the worst results from the perspective of mechanical properties about tensile strength and flexural strength, which failed to reach that of the natural bone at the 12th week. Comprehensive results displayed that C group with 20-μm coating was better than others in mechanical properties, while there is no difference between B and C groups in hematology. Degradation rate is inversely proportional to the coating thickness. And magnesium alloy with a 20-μm coating is more suitable for the fracture fixation.

ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA. USEPA DEMONSTRATION PROJECT AT VALLEY VISTA, AZ FINAL PERFORMANCE EVALUATION REPORT

EPA Science Inventory

This report documents the activities performed during and the results obtained from the arsenic removal treatment technology demonstration project at an Arizona Water Company (AWC) facility in Sedona, AZ, commonly referred to as Valley Vista. The objectives of the project were t...

Ratcheting Strain and Microstructure Evolution of AZ31B Magnesium Alloy under a Tensile-Tensile Cyclic Loading

PubMed Central

Wang, Denghui; Wang, Wenxian; Zhou, Jun; He, Xiuli; Dong, Peng; Zhang, Hongxia; Sun, Liyong

2018-01-01

In this paper, studies were conducted to investigate the deformation behavior and microstructure change in a hot-rolled AZ31B magnesium alloy during a tensile-tensile cyclic loading. The relationship between ratcheting effect and microstructure change was discussed. The ratcheting effect in the material during current tensile-tensile fatigue loading exceeds the material’s fatigue limit and the development of ratcheting strain in the material experienced three stages: initial sharp increase stage (Stage I); steady stage (Stage II); and final abrupt increase stage (Stage III). Microstructure changes in Stage I and Stage II are mainly caused by activation of basal slip system. The Extra Geometrically Necessary Dislocations (GNDs) were also calculated to discuss the relationship between the dislocation caused by the basal slip system and the ratcheting strain during the cyclic loading. In Stage III, both the basal slip and the {11−20} twins are found active during the crack propagation. The fatigue crack initiation in the AZ31B magnesium alloy is found due to the basal slip and the {11−20} tensile twins. PMID:29597278

Ratcheting Strain and Microstructure Evolution of AZ31B Magnesium Alloy under a Tensile-Tensile Cyclic Loading.

PubMed

Yan, Zhifeng; Wang, Denghui; Wang, Wenxian; Zhou, Jun; He, Xiuli; Dong, Peng; Zhang, Hongxia; Sun, Liyong

2018-03-28

In this paper, studies were conducted to investigate the deformation behavior and microstructure change in a hot-rolled AZ31B magnesium alloy during a tensile-tensile cyclic loading. The relationship between ratcheting effect and microstructure change was discussed. The ratcheting effect in the material during current tensile-tensile fatigue loading exceeds the material's fatigue limit and the development of ratcheting strain in the material experienced three stages: initial sharp increase stage (Stage I); steady stage (Stage II); and final abrupt increase stage (Stage III). Microstructure changes in Stage I and Stage II are mainly caused by activation of basal slip system. The Extra Geometrically Necessary Dislocations (GNDs) were also calculated to discuss the relationship between the dislocation caused by the basal slip system and the ratcheting strain during the cyclic loading. In Stage III, both the basal slip and the {11-20} twins are found active during the crack propagation. The fatigue crack initiation in the AZ31B magnesium alloy is found due to the basal slip and the {11-20} tensile twins.

A systematic study of mechanical properties, corrosion behavior and biocompatibility of AZ31B Mg alloy after ultrasonic nanocrystal surface modification.

PubMed

Hou, Xiaoning; Qin, Haifeng; Gao, Hongyu; Mankoci, Steven; Zhang, Ruixia; Zhou, Xianfeng; Ren, Zhencheng; Doll, Gary L; Martini, Ashlie; Sahai, Nita; Dong, Yalin; Ye, Chang

2017-09-01

Magnesium alloys have tremendous potential for biomedical applications due to their good biocompatibility, osteoconductivity, and degradability, but can be limited by their poor mechanical properties and fast corrosion in the physiological environment. In this study, ultrasonic nanocrystal surface modification (UNSM), a recently developed surface processing technique that utilizes ultrasonic impacts to induce plastic strain on metal surfaces, was applied to an AZ31B magnesium (Mg) alloy. The mechanical properties, corrosion resistance, and biocompatibility of the alloy after UNSM treatment were studied systematically. Significant improvement in hardness, yield stress and wear resistance was achieved after the UNSM treatment. In addition, the corrosion behavior of UNSM-treated AZ31B was not compromised compared with the untreated samples, as demonstrated by the weight loss and released element concentrations of Mg and Al after immersion in alpha-minimum essential medium (α-MEM) for 24h. The in vitro biocompatibility of the AZ31B Mg alloys toward adipose-derived stem cells (ADSCs) before and after UNSM processing was also evaluated using a cell culture study. Comparable cell attachments were achieved between the two groups. These studies showed that UNSM could significantly improve the mechanical properties of Mg alloys without compromising their corrosion rate and biocompatibility in vitro. These findings suggest that UNSM is a promising method to treat biodegradable Mg alloys for orthopaedic applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Mechanical Properties and Microstructure of AZ31B Magnesium Alloy Processed by I-ECAP

NASA Astrophysics Data System (ADS)

Gzyl, Michal; Rosochowski, Andrzej; Pesci, Raphael; Olejnik, Lech; Yakushina, Evgenia; Wood, Paul

2014-03-01

Incremental equal channel angular pressing (I-ECAP) is a severe plastic deformation process used to refine grain size of metals, which allows processing very long billets. As described in the current article, an AZ31B magnesium alloy was processed for the first time by three different routes of I-ECAP, namely, A, BC, and C, at 523 K (250 °C). The structure of the material was homogenized and refined to ~5 microns of the average grain size, irrespective of the route used. Mechanical properties of the I-ECAPed samples in tension and compression were investigated. Strong influence of the processing route on yield and fracture behavior of the material was established. It was found that texture controls the mechanical properties of AZ31B magnesium alloy subjected to I-ECAP. SEM and OM techniques were used to obtain microstructural images of the I-ECAPed samples subjected to tension and compression. Increased ductility after I-ECAP was attributed to twinning suppression and facilitation of slip on basal plane. Shear bands were revealed in the samples processed by I-ECAP and subjected to tension. Tension-compression yield stress asymmetry in the samples tested along extrusion direction was suppressed in the material processed by routes BC and C. This effect was attributed to textural development and microstructural homogenization. Twinning activities in fine- and coarse-grained samples have also been studied.

Advanced characterization study of commercial conversion and electrocoating structures on magnesium alloys AZ31B and ZE10A

DOE PAGES

Brady, Michael P.; Leonard, Donovan N.; Meyer, III, Harry M.; ...

2016-03-31

The local metal-coating interface microstructure and chemistry formed on commercial magnesium alloys Mg–3Al–1Zn (AZ31B) and Mg–1Zn–0.25Zr–<0.5Nd (ZE10A, ZEK100 type) were analyzed as-chemical conversion coated with a commercial hexafluoro-titanate/zirconate type + organic polymer based treatment (Bonderite® 5200) and a commercial hexafluoro-zirconate type + trivalent chromium Cr3 + type treatment (Surtec® 650), and after the same conversion coatings followed by electrocoating with an epoxy based coating, Cathoguard® 525. Characterization techniques included scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and cross-section scanning transmission electron microscopy (STEM). Corrosion behavior was assessed in room temperature saturated aqueous Mg(OH)2 solution with 1 wt.% NaCl. Themore » goal of the effort was to assess the degree to which substrate alloy additions become enriched in the conversion coating, and how the conversion coating was impacted by subsequent electrocoating. Key findings included the enrichment of Al from AZ31B and Zr from ZE10A, respectively, into the conversion coating, with moderate corrosion resistance benefits for AZ31B when Al was incorporated. Varying degrees of increased porosity and modification of the initial conversion coating chemistry at the metal-coating interface were observed after electrocoating. These changes were postulated to result in degraded electrocoating protectiveness. As a result, these observations highlight the challenges of coating Mg, and the need to tailor electrocoating in light of potential degradation of the initial as-conversion coated Mg alloy surface.« less

Electrochemical characteristics of calcium-phosphatized AZ31 magnesium alloy in 0.9 % NaCl solution.

PubMed

Hadzima, Branislav; Mhaede, Mansour; Pastorek, Filip

2014-05-01

Magnesium alloys suffer from their high reactivity in common environments. Protective layers are widely created on the surface of magnesium alloys to improve their corrosion resistance. This article evaluates the influence of a calcium-phosphate layer on the electrochemical characteristics of AZ31 magnesium alloy in 0.9 % NaCl solution. The calcium phosphate (CaP) layer was electrochemically deposited in a solution containing 0.1 M Ca(NO3)2, 0.06 M NH4H2PO4 and 10 ml l(-1) of H2O2. The formed surface layer was composed mainly of brushite [(dicalcium phosphate dihidrate (DCPD)] as proved by energy-dispersive X-ray analysis. The surface morphology was observed by scanning electron microscopy. Immersion test was performed in order to observe degradation of the calcium phosphatized surfaces. The influence of the phosphate layer on the electrochemical characteristics of AZ31, in 0.9 % NaCl solution, was evaluated by potentiodynamic measurements and electrochemical impedance spectroscopy. The obtained results were analysed by the Tafel-extrapolation method and equivalent circuits method. The results showed that the polarization resistance of the DCPD-coated surface is about 25 times higher than that of non-coated surface. The CaP electro-deposition process increased the activation energy of corrosion process.

In Vitro Analysis of Electrophoretic Deposited Fluoridated Hydroxyapatite Coating on Micro-arc Oxidized AZ91 Magnesium Alloy for Biomaterials Applications

NASA Astrophysics Data System (ADS)

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

2015-03-01

Magnesium (Mg) alloys have been recently introduced as a biodegradable implant for orthopedic applications. However, their fast corrosion, low bioactivity, and mechanical integrity have limited their clinical applications. The main aim of this research was to improve such properties of the AZ91 Mg alloy through surface modifications. For this purpose, nanostructured fluoridated hydroxyapatite (FHA) was coated on AZ91 Mg alloy by micro-arc oxidation and electrophoretic deposition method. The coated alloy was characterized through scanning electron microscopy, transmission electron microscopy, X-ray diffraction, in vitro corrosion tests, mechanical tests, and cytocompatibility evaluation. The results confirmed the improvement of the corrosion resistance, in vitro bioactivity, mechanical integrity, and the cytocompatibility of the coated Mg alloy. Therefore, the nanostructured FHA coating can offer a promising way to improve the properties of the Mg alloy for orthopedic applications.

Effect of Thickness on the Morphology and Corrosion Behavior of Cerium-Based Conversion Coatings on AZ31B Magnesium Alloy

NASA Astrophysics Data System (ADS)

Castano, Carlos E.; Maddela, Surender; O'Keefe, Matthew J.; Wang, Yar-Ming

Cerium-based conversion coatings (CeCCs) were deposited onto AZ31B magnesium alloy substrates using a spontaneous reaction of CeCl3, H2O2 and gelatin in a water-based solution. The coating thickness was adjusted by controlling the immersion time in the deposition solution. Prior to deposition, the AZ31B substrates were treated using an acid pickling in nitric acid and then an alkaline cleaning in sodium metasilicate pentahydrate. After deposition, the coated samples were immersed in a phosphate bath that converted cerium oxide/hydroxide into cerium phosphate. Electrochemical impedance spectroscopy, potentiodynamic polarization and neutral salt spray testing studies indicated that 100 nm thick CeCC had better corrosion performance than 400 nm coatings. Characterization of the CeCCs by transmission electron microscopy (TEM) revealed a three layer structure with different compositions.

ARSENIC REMOVAL FROM DRINKING WATER BY ADSORPTIVE MEDIA USEPA DEMONSTRATION PROJECT AT VALLEY VISTA, AZ SIX-MONTH EVALUATION REPORT

EPA Science Inventory

This report documents the activities performed and the results obtained from the first six months of the EPA arsenic removal technology demonstration project at the Arizona Water Company (AWC) facility in Sedona, AZ, commonly referred to as Valley Vista. The main objective of the...

Development of Graphene Nanoplatelet-Reinforced AZ91 Magnesium Alloy by Solidification Processing

NASA Astrophysics Data System (ADS)

Kandemir, Sinan

2018-04-01

It is a challenging task to effectively incorporate graphene nanoplatelets (GNPs) which have recently emerged as potential reinforcement for strengthening metals into magnesium-based matrices by conventional solidification processes due to their large surface areas and poor wettability. A solidification processing which combines mechanical stirring and ultrasonic dispersion of reinforcements in liquid matrix was employed to develop AZ91 magnesium alloy matrix composites reinforced with 0.25 and 0.5 wt.% GNPs. The microstructural studies conducted with scanning and transmission electron microscopes revealed that fairly uniform distribution and dispersion of GNPs through the matrix were achieved due to effective combination of mechanical and ultrasonic stirring. The GNPs embedded into the magnesium matrix led to significant enhancement in the hardness, tensile strength and ductility of the composites compared to those of unreinforced AZ91 alloy. The strength enhancement was predominantly attributed to the grain refinement by the GNP addition and dislocation generation strengthening due to the coefficient of thermal expansion mismatch between the matrix and reinforcement. The improved ductility was attributed to the refinement of β eutectics by transforming from lamellar to the divorced eutectics due to the GNP additions. In addition, the strengthening efficiency of the composite with 0.25 wt.% GNP was found to be higher than those of the composite with 0.5 wt.% GNP as the agglomeration tendency of GNPs is increased with increasing GNP content. These results were compared with those of the GNP-reinforced magnesium composites reported in the literature, indicating the potential of the process introduced in this study in terms of fabricating light and high-performance metal matrix composites.

An investigation of enhanced mercury bioaccumulation in fish from offshore feeding.

PubMed

Chételat, John; Cloutier, Louise; Amyot, Marc

2013-08-01

We investigated the dietary pathways of mercury transfer in the food web of Morency Lake (Canada) to determine the influence of carbon source and habitat use on mercury bioaccumulation in fish. Whole-body concentrations of methylmercury (MeHg) were significantly different in four fish species (white sucker, brown bullhead, pumpkinseed and smallmouth bass) and increased with both trophic position and greater feeding on offshore (versus littoral) carbon. An examination of fish gut contents and the depth distribution of invertebrates in Morency Lake showed that smallmouth bass and brown bullhead were supplementing their littoral diet with the consumption of either opossum shrimp (Mysis diluviana) or profundal amphipods in offshore waters. The zooplanktivore Mysis had significantly higher MeHg concentrations than zooplankton and benthic invertebrates, and it was an elevated source of MeHg to smallmouth bass. In contrast, profundal amphipods consumed by brown bullhead did not have higher MeHg concentrations than littoral amphipods. Instead, partitioning of benthic invertebrate resources likely explains the greater MeHg bioaccumulation in brown bullhead, associated with offshore feeding of amphipods. White sucker and brown bullhead had a similar trophic position but white sucker consumed more chironomids, which had one-third the MeHg concentration of amphipods. Our findings suggest that offshore feeding in a lake can affect fish MeHg bioaccumulation via two different processes: (1) the consumption of MeHg-enriched pelagic prey, or (2) resource partitioning of benthic primary consumers with different MeHg concentrations. These observations on the mechanisms of habitat-specific bioaccumulation highlight the complexity of MeHg transfer through lake food webs.

77 FR 12501 - Changes in Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-01

... Monroe Business Gazette. Street, Peoria, AZ 85345. Colorado: Arapahoe City of Centennial December 8, 2011... Littleton Centennial, 13133 East Independent. Arapahoe Road, Centennial, CO 80112. Arapahoe City of Centennial December 8, 2011; The Honorable Cathy Noon, April 13, 2012 080315 (11-08-1095P). December 15, 2011...

77 FR 50626 - Changes in Flood Elevation Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2012-08-22

.... Street, Peoria, AZ 85345. Colorado: Arapahoe (FEMA Docket No.: B- City of Centennial December 8, 2011... of The Littleton Centennial, 13133 East Independent. Arapahoe Road, Centennial, CO 80112. Arapahoe (FEMA Docket No.: B- City of Centennial December 8, 2011; The Honorable Cathy Noon, April 13, 2012...

In vivo assessments of bioabsorbable AZ91 magnesium implants coated with nanostructured fluoridated hydroxyapatite by MAO/EPD technique for biomedical applications.

PubMed

Razavi, Mehdi; Fathi, Mohammadhossein; Savabi, Omid; Vashaee, Daryoosh; Tayebi, Lobat

2015-03-01

Although magnesium (Mg) is a unique biodegradable metal which possesses mechanical property similar to that of the natural bone and can be an attractive material to be used as orthopedic implants, its quick corrosion rate restricts its actual clinical applications. To control its rapid degradation, we have modified the surface of magnesium implant using fluoridated hydroxyapatite (FHA: Ca10(PO4)6OH2-xFx) through the combined micro-arc oxidation (MAO) and electrophoretic deposition (EPD) techniques, which was presented in our previous paper. In this article, the biocompatibility examinations were conducted on the coated AZ91 magnesium alloy by implanting it into the greater trochanter area of rabbits. The results of the in vivo animal test revealed a significant enhancement in the biocompatibility of FHA/MAO coated implant compared to the uncoated one. By applying the FHA/MAO coating on the AZ91 implant, the amount of weight loss and magnesium ion release in blood plasma decreased. According to the histological results, the formation of the new bone increased and the inflammation decreased around the implant. In addition, the implantation of the uncoated AZ91 alloy accompanied by the release of hydrogen gas around the implant; this release was suppressed by applying the coated implant. Our study exemplifies that the surface coating of magnesium implant using a bioactive ceramic such as fluoridated hydroxyapatite may improve the biocompatibility of the implant to make it suitable as a commercialized biomedical product. Published by Elsevier B.V.

Influence of MC3T3-E1 preosteoblast culture on the corrosion of a T6-treated AZ91 alloy

PubMed Central

Brooks, Emily K.; Tobias, Menachem E.; Yang, Shuying; Bone, Lawrence B.; Ehrensberger, Mark T.

2015-01-01

This study investigated the corrosion of artificially aged T6 heat-treated Mg-9%Al-1%Zn (AZ91) for biomedical applications. Corrosion tests and surface analysis were completed both with and without a monolayer of mouse preosteoblast MC3T3-E1 cells cultured on the sample. Electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to explore the corrosion processes after either 3 or 21 days of AZ91 incubation in cell culture medium (CCM). The EIS showed both the inner layer resistance (Rin) and outer layer resistance (Rout) were lower for samples without cells cultured on the surface at 3 days (Rin = 2.64 e4 Ω/cm2, Rout = 140 Ω/cm2) compared to 21 days (Rin = 3.60 e4 Ω/cm2, Rout = 287 Ω/cm2) due to precipitation of magnesium and calcium phosphates over time. Samples with preosteoblasts cultured on the surface had a slower initial corrosion (3 day, Rin = 1.88 e5 Ω/cm2, Rout = 1060 Ω/cm2) which was observed to increase over time (21 day, Rin = 2.99 e4 Ω/cm2, Rout = 287 Ω/cm2). Changes in the corrosion processes were thought to be related to changes in the coverage provided by the cell layer. Our results reveal that the presence of cells and biological processes are able to significantly influence the corrosion rate of AZ91. PMID:25715925

Learning Cities as Healthy Green Cities: Building Sustainable Opportunity Cities

ERIC Educational Resources Information Center

Kearns, Peter

2012-01-01

This paper discusses a new generation of learning cities we have called EcCoWell cities (Economy, Community, Well-being). The paper was prepared for the PASCAL International Exchanges (PIE) and is based on international experiences with PIE and developments in some cities. The paper argues for more holistic and integrated development so that…

Friction Stir Welding of Magnesium Alloy Type AZ 31

NASA Astrophysics Data System (ADS)

Kupec, Tomáš; Behúlová, Mária; Turňa, Milan; Sahul, Miroslav

The paper deals with welding of Mg alloy of the type AZ 31 by Friction Stir Welding technology (FSW). The FSW technology is at present predominantly used for welding light metals and alloys, as aluminium, magnesium and their alloys. Experimental part consists of performing the simulation and fabrication of welded joints on a new-installed welding equipment available at the Welding Research Institute — Industrial Institute of SR Bratislava. Welding tools made of tool steel type H 13 were used for welding experiments. Geometry of welding tools was designed on the base of literature knowledge. Suitable welding parameters and conditions were determined using numerical simulation. Main emphasis was laid upon the tool revolutions, welding speed and tool bevel angle. The effect of welding parameters on the quality of welded joints was assessed. Assessment of welded joints was carried out by radiography, light microscopy, hardness measurement and EDX microanalysis. Static tensile test was employed for mechanical testing.

The one-step electroposition of superhydrophobic surface on AZ31 magnesium alloy and its time-dependence corrosion resistance in NaCl solution

NASA Astrophysics Data System (ADS)

Zhong, Yuxing; Hu, Jin; Zhang, Yufen; Tang, Shawei

2018-01-01

A calcium myristic superhydrophobicity coating with a hierarchical micro-nanostructure was fabricated on AZ31 magnesium alloy by one-step electroposition. The effects of deposition time on the coating structure, such as morphology, thickness, wettability and phase composition of the coating were studied. The corrosion behavior of the coated samples in 3.5% NaCl solution was also investigated and the corrosion mechanism was discussed. It was found that the deposition time has a visible effect on the morphology, thickness and wettability, which distinctly affects the corrosion resistance of coatings. The corrosion resistance of the coating gradually decreases with the increase in the immersion time due to the disappearance of the air layer which exists on the coating surface. The superhydrophobic surfaces present the temporal limitations to the corrosion resistance of AZ31 magnesium alloy.

Hot deformation characteristics of AZ80 magnesium alloy: Work hardening effect and processing parameter sensitivities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Y.; Wan, L.; Guo, Z. H.

Isothermal compression experiment of AZ80 magnesium alloy was conducted by Gleeble thermo-mechanical simulator in order to quantitatively investigate the work hardening (WH), strain rate sensitivity (SRS) and temperature sensitivity (TS) during hot processing of magnesium alloys. The WH, SRS and TS were described by Zener-Hollomon parameter (Z) coupling of deformation parameters. The relationships between WH rate and true strain as well as true stress were derived from Kocks-Mecking dislocation model and validated by our measurement data. The slope defined through the linear relationship of WH rate and true stress was only related to the annihilation coefficient Ω. Obvious WH behaviormore » could be exhibited at a higher Z condition. Furthermore, we have identified the correlation between the microstructural evolution including β-Mg17Al12 precipitation and the SRS and TS variations. Intensive dynamic recrystallization and homogeneous distribution of β-Mg17Al12 precipitates resulted in greater SRS coefficient at higher temperature. The deformation heat effect and β-Mg17Al12 precipitate content can be regarded as the major factors determining the TS behavior. At low Z condition, the SRS becomes stronger, in contrast to the variation of TS. The optimum hot processing window was validated based on the established SRS and TS values distribution maps for AZ80 magnesium alloy.« less

Galactic City at the Edge of the Universe

NASA Image and Video Library

2011-01-12

Astronomers have discovered a massive cluster of young galaxies forming in the distant universe. The growing galactic metropolis is known as COSMOS-AzTEC3. This image was taken Japan Subaru telescope atop Mauna Kea in Hawaii.

EAST VERSUS WEST IN THE US: CHEMICAL CHARACTERISTICS OF PM 2.5 DURING THE WINTER OF 1998

EPA Science Inventory

PM2.5 samples were collected for up to 20 days during January and February of 1998 in four US cities. Samplers were collected for 24-hr sampling periods every other day at Philadelphia, PA, Phoenix, AZ, Rubidoux, CA, and Research Triangle Park, NC. These cities were chosen due ...

Al-TiC in situ composite coating fabricated by low power pulsed laser cladding on AZ91D magnesium alloy

NASA Astrophysics Data System (ADS)

Yang, Liuqing; Li, Zhiyong; Zhang, Yingqiao; Wei, Shouzheng; Liu, Fuqiang

2018-03-01

Al + (Ti + B4C) composite coating was cladded on AZ91D magnesium alloy by a low power pulsed Nd-YAG laser. The Ti+B4C mixed powder is with the ratio of Ti: B4C = 5:1, which was then mixed with Al powder by weight fraction of 10%, 15% and 20%, respectively. Scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction were used to study the microstructure, chemical composition and phase composition of the coating. Results showed that the coating had satisfied metallurgical bonding with the magnesium substrate. Al3Mg2, Al12Mg17, Al3Ti and TiC were formed by in-situ reaction. The coatings have micro-hardness of 348HV, which is about 5-6 times higher than that of AZ91D. The wear resistance and corrosion resistance of the coatings are enhanced with the addition of the mixed powder.

Evolution of the Corrosion Morphology on AZ31B Tracked Electrochemically and by In Situ Microscopy in Chloride-Containing Media

NASA Astrophysics Data System (ADS)

Melia, M. A.; Cain, T. W.; Briglia, B. F.; Scully, J. R.; Fitz-Gerald, J. M.

2017-11-01

The evolution of open-circuit corrosion morphology as a function of immersion time for Mg alloy AZ31B in 0.6-M NaCl solution was investigated. Real-time optical microscopy accompanied by simultaneous electrochemical characterization was used to characterize the filiform corrosion (FFC) of AZ31B. Specifically, the behavior of propagating corrosion filaments on the metal surface was observed, and correlations among polarization resistance, filament propagation rates, open-circuit potential, and active coverage of local corrosion sites were revealed. Three distinct stages of corrosion were observed in 0.6-M NaCl. An initial passive region, during which a slow potential rise occurred (termed stage I), a second FFC region (termed stage II) with shallow penetrating, distinct filaments, and a final FFC region (termed stage III) with deeper penetrating filaments, aligned to form a linear front. The electrochemical properties of each stage are discussed, providing insights into the penetration rates and corrosion model.

[Prediction instrument for obesity in adolescents at the Policlínico Universitario "Manuel González Díaz", 2013-2014].

PubMed

Piña Borrego, Carlos Enrique; Fernández Fernández, María de Lourdes; Fonte Rodríguez, Norge; Piña Rodríguez, Lorena Karla

Obesity is one of the principal non declarable diseases affecting children and adolescents. With the objective of developing a predictive instrument to identify high-risk adolescents with obesity, a cohort prospective study was carried out at the Policlinic "Manuel González Díaz", Bahía Honda City from 2013-2014. It was developed in three stages. In the first stage, 1800 adolescents from 10-19 years of age were included. The prevalence was identified and the most relevant characteristics of obesity were described (defined as body mass index >97 th percentile according to age and sex). In the second stage we identified the possibility of the diagnosis of factors that increase the probability of obesity. The third stage elaborated and validated an obesity predictor instrument from the results of the initial stages. To apply the instrument to sample A for internal elaboration and validation, sensitivity was 77.78% and specificity was 86.11%. Area under the curve (AUC) receiver operating characteristic (ROC) was 0.86, whereas for sample B the sensitivity was 79.63% and specificity was 92.13%. Positive predictive value (PPV) was 83.5% and negative predictive value (NPV) was 90.05%. The instrument allows predicting the risk for developing obesity in adolescents with acceptable sensitivity and high specificity. Its routine application will be interesting in pediatric health consultations. Copyright © 2014 Hospital Infantil de México Federico Gómez. Publicado por Masson Doyma México S.A. All rights reserved.

Influence of MC3T3-E1 preosteoblast culture on the corrosion of a T6-treated AZ91 alloy.

PubMed

Brooks, Emily K; Tobias, Menachem E; Yang, Shuying; Bone, Lawrence B; Ehrensberger, Mark T

2016-02-01

This study investigated the corrosion of artificially aged T6 heat-treated Mg-9%Al-1%Zn (AZ91) for biomedical applications. Corrosion tests and surface analysis were completed both with and without a monolayer of mouse preosteoblast MC3T3-E1 cells cultured on the sample. Electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to explore the corrosion processes after either 3 or 21 days of AZ91 incubation in cell culture medium (CCM). The EIS showed both the inner layer resistance (Rin ) and outer layer resistance (Rout ) were lower for samples without cells cultured on the surface at 3 days (Rin  = 2.64 e4 Ω/cm(2) , Rout  = 140 Ω/cm(2) ) compared to 21 days (Rin  = 3.60 e4 Ω/cm(2) , Rout  = 287 Ω/cm(2) ) due to precipitation of magnesium and calcium phosphates over time. Samples with preosteoblasts cultured on the surface had a slower initial corrosion (3 day, Rin  = 1.88 e5 Ω/cm(2) , Rout  = 1060 Ω/cm(2) ) which was observed to increase over time (21 day, Rin  = 2.99 e4 Ω/cm(2) , Rout  = 287 Ω/cm(2) ). Changes in the corrosion processes were thought to be related to changes in the coverage provided by the cell layer. Our results reveal that the presence of cells and biological processes are able to significantly influence the corrosion rate of AZ91. © 2015 Wiley Periodicals, Inc.

Soda intake and tobacco use among young adult bar patrons: A cross-sectional study in seven cities.

PubMed

Kearns, Cristin E; Lisha, Nadra E; Ling, Pamela M

2018-06-01

Young adults are among the greatest consumers of sugar sweetened beverages, and they also have high smoking rates. However, few studies address the relationship between these risk behaviors; this study examined the relationship between soda consumption and smoking among young adult bar patrons, a high-risk understudied population. A cross-sectional survey of young adult bar patrons (between January 2014 and October 2015) was conducted using randomized time location sampling (N = 8712) in Albuquerque, NM, Los Angeles, CA Nashville, TN, Oklahoma City, OK, San Diego, CA, San Francisco, CA, and Tucson, AZ. The survey found the prevalences of daily regular soda intake ranged from 32% in San Diego to 51% in Oklahoma City and current smoking ranged from 36% in Los Angeles, CA to 49% in Albuquerque, NM. In multinomial multivariate models with no soda consumption as the reference group and controlling for demographics and location, non-daily (OR = 1.24, 95% CI = 1.05, 1.47) and daily smokers (OR = 1.34, 95% CI = 1.08, 1.66) were both more likely to drink regular soda compared to not drinking any soda. No effects were found for diet soda consumption. These linked risks suggest that comprehensive health promotion efforts to decrease sugar sweetened beverage consumption and tobacco use, among other risky behaviors, may be effective in this population.

CityGML - Interoperable semantic 3D city models

NASA Astrophysics Data System (ADS)

Gröger, Gerhard; Plümer, Lutz

2012-07-01

CityGML is the international standard of the Open Geospatial Consortium (OGC) for the representation and exchange of 3D city models. It defines the three-dimensional geometry, topology, semantics and appearance of the most relevant topographic objects in urban or regional contexts. These definitions are provided in different, well-defined Levels-of-Detail (multiresolution model). The focus of CityGML is on the semantical aspects of 3D city models, its structures, taxonomies and aggregations, allowing users to employ virtual 3D city models for advanced analysis and visualization tasks in a variety of application domains such as urban planning, indoor/outdoor pedestrian navigation, environmental simulations, cultural heritage, or facility management. This is in contrast to purely geometrical/graphical models such as KML, VRML, or X3D, which do not provide sufficient semantics. CityGML is based on the Geography Markup Language (GML), which provides a standardized geometry model. Due to this model and its well-defined semantics and structures, CityGML facilitates interoperable data exchange in the context of geo web services and spatial data infrastructures. Since its standardization in 2008, CityGML has become used on a worldwide scale: tools from notable companies in the geospatial field provide CityGML interfaces. Many applications and projects use this standard. CityGML is also having a strong impact on science: numerous approaches use CityGML, particularly its semantics, for disaster management, emergency responses, or energy-related applications as well as for visualizations, or they contribute to CityGML, improving its consistency and validity, or use CityGML, particularly its different Levels-of-Detail, as a source or target for generalizations. This paper gives an overview of CityGML, its underlying concepts, its Levels-of-Detail, how to extend it, its applications, its likely future development, and the role it plays in scientific research. Furthermore, its

(Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. IV. Physical properties derived from spectral energy distributions

NASA Astrophysics Data System (ADS)

Miettinen, O.; Delvecchio, I.; Smolčić, V.; Novak, M.; Aravena, M.; Karim, A.; Murphy, E. J.; Schinnerer, E.; Capak, P.; Ilbert, O.; Intema, H. T.; Laigle, C.; McCracken, H. J.

2017-01-01

Context. Submillimetre galaxies (SMGs) in the early Universe are potential antecedents of the most massive galaxies we see in the present-day Universe. An important step towards quantifying this galactic evolutionary connection is to investigate the fundamental physical properties of SMGs, such as their stellar mass content (M⋆) and star formation rate (SFR). Aims: We attempt to characterise the physical nature of a 1.1 mm selected, flux-limited, and interferometrically followed up sample of SMGs in the COSMOS field. Methods: We used the latest release of the MAGPHYS code to fit the multiwavelength (UV to radio) spectral energy distributions (SEDs) of 16 of the target SMGs, which lie at redshifts z ≃ 1.6-5.3. We also constructed the pure radio SEDs of our SMGs using three different radio bands (325 MHz, 1.4 GHz, and 3 GHz). Moreover, since two SMGs in our sample, AzTEC 1 and AzTEC 3, benefit from previous 12C16O line observations, we studied their properties in more detail. Results: The median and 16th-84th percentile ranges of M⋆, infrared (8-1000 μm) luminosity (LIR), SFR, dust temperature (Tdust), and dust mass (Mdust) were derived to be log (M⋆/M⊙) = 10.96+ 0.34-0.19, log (LIR/L⊙) = 12.93+ 0.09-0.19, SFR = 856+ 191-310M⊙ yr-1, Tdust = 40.6+ 7.5-8.1 K, and log (Mdust/M⊙) = 9.17+ 0.03-0.33, respectively. We found that 63% of our target SMGs lie above the galaxy main sequence by more than a factor of 3 and, hence, are starbursts. The 3 GHz radio sizes we have previously measured for the target SMGs were compared with the present M⋆ estimates, and we found that the z> 3 SMGs are fairly consistent with the mass-size relationship of z 2 compact, quiescent galaxies (cQGs). The median radio spectral index is found to be α = -0.77+ 0.28-0.42. The median IR-radio correlation parameter is found to be q = 2.27+ 0.27-0.13, which is lower than was measured locally (median q = 2.64). The gas-to-dust mass ratio for AzTEC 1 is derived to be δgdr = 90+ 23

Effect of Annealing on Microstructure, Texture and Tensile Properties of Twin-Roll Cast AZ31B

NASA Astrophysics Data System (ADS)

Masoumi, Mohsen; Zarandi, Faramarz; Pekguleryuz, Mihriban O.

Twin-roll cast (TRC) AZ31 alloy (Mg-3wt.%Al-1wt.%Zn) was subjected to heat treatment at 420 °C. As a result, the intensity of the original basal texture was reduced considerably. Crystallographic orientation analysis revealed that such a change in the texture is due to particle-stimulated nucleation of new grains with random orientations. The tensile test results indicate that annealing slightly increases ultimate tensile strength (UTS), however, dramatically improves the elongation.

Effect of Stress Triaxiality on the Flow and Fracture of Mg Alloy AZ31

NASA Astrophysics Data System (ADS)

Kondori, Babak; Benzerga, A. Amine

2014-07-01

The microscopic damage mechanisms operating in a hot-rolled magnesium alloy AZ31B are investigated under both uniaxial and controlled triaxial loadings. Their connection to macroscopic fracture strains and fracture mode (normal vs shear) is elucidated using postmortem fractography, interrupted tests, and microscopic analysis. The fracture locus (strain-to-failure vs stress triaxiality) exhibits a maximum at moderate triaxiality, and the strain-to-failure is found to be greater in notched specimens than in initially smooth ones. A transition from twinning-induced fracture under uniaxial loading to microvoid coalescence fracture under triaxial loading is evidenced. It is argued that this transition accounts in part for the observed greater ductility in notched bars. The evolution of plastic anisotropy with stress triaxiality is also investigated. It is inferred that anisotropic plasticity at a macroscopic scale suffices to account for the observed transition in the fracture mode from flat (triaxial loading) to shear-like (uniaxial loading). Damage is found to initiate at second-phase particles and deformation twins. Fracture surfaces of broken specimens exhibit granular morphology, coarse splits, twin-sized crack traces, as well as shallow and deep dimples, in proportions that depend on the overall stress triaxiality and fracture mode. An important finding is that AZ31B has a greater tolerance to ductile damage accumulation than has been believed thus far, based on the fracture behavior in uniaxial specimens. Another finding, common to both tension and compression, is the increase in volumetric strain, the microscopic origins of which remain to be elucidated.

The Preparation, Characterization and Formation Mechanism of a Calcium Phosphate Conversion Coating on Magnesium Alloy AZ91D.

PubMed

Liu, Dong; Li, Yanyan; Zhou, Yong; Ding, Yigang

2018-05-28

The poor corrosion resistance of magnesium alloys is one of the main obstacles preventing their widespread usage. Due to the advantages of lower cost and simplicity in operation, chemical conversion coating has drawn considerable attention for its improvement of the corrosion resistance of magnesium alloys. In this study, a calcium phosphate coating was prepared on magnesium alloy AZ91D by chemical conversion. For the calcium phosphate coating, the effect of processing parameters on the microstructure and corrosion resistance was studied by scanning electron microscope (SEM) and electrochemical methods, and the coating composition was characterized by X-ray diffraction (XRD). The calcium phosphate coating was mainly composed of CaHPO₄·2H₂O (DCPD), with fewer cracks and pores. The coating with the leaf-like microstructure provided great corrosion resistance to the AZ91D substrate, and was obtained under the following conditions: 20 min, ambient temperature, and no stirring. At the same time, the role of NH₄H₂PO₄ as the coating-forming agent and the acidifying agent in the conversion process was realized, and the formation mechanism of DCPD was discussed in detail in this work.

78 FR 8166 - Changes in Flood Hazard Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-05

... West Durango 040037-102IC.pdf. (12-09-2621P). Maricopa County Street, Phoenix, AZ Board of 85009.... City of San Obispo, CA 93401. Luis Obispo, 990 Palm Street, San Luis Obispo, CA 93401. Colorado: Adams.../colorado/ Westminster, CO 80031. adams/. 4800 West 92nd Avenue, Westminster, CO 80031. Arapahoe City of...

31 CFR 342.9 - Fiscal agents.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Fiscal agents. 342.9 Section 342.9 Money and Finance: Treasury Regulations Relating to Money and Finance (Continued) FISCAL SERVICE... Avenue, Kansas City, MO 64198 Dallas, San Francisco, Kansas City, St. Louis AK, AR, AZ, CA, CO, HI, ID...

Effects of the Strain Rate and Temperature on the Microstructural Evolution of Twin-Rolled Cast Wrought AZ31B Alloys Sheets

NASA Astrophysics Data System (ADS)

Rodriguez, A. K.; Kridli, G.; Ayoub, G.; Zbib, H.

2013-10-01

This article investigates the effects of the strain rate and temperature on the microstructural evolution of twin-rolled cast wrought AZ31B sheets. This was achieved through static heating and through tensile test performed at strain rates from 10-4 to 10-1 s-1 and temperatures between room temperature (RT) and 300 °C. While brittle fracture with high stresses and limited elongation was observed at the RT, ductile behavior was obtained at higher temperatures with low strain rates. The strain rate sensitivity and activation energy calculations indicate that grain boundary diffusion and lattice diffusion are the two rate-controlling mechanisms at warm and high temperatures, respectively. An analysis of the evolution of the microstructure provided some indications of the most probable deformation mechanisms in the material: twinning operates at lower temperatures, and dynamic recrystallization dominates at higher temperatures. The static evolution of the microstructure was also studied, proving a gradual static grain growth of the AZ31B with annealing temperature and time.

Comparison Study II: Double Star Measurements Made Using an Equatorial Mounted Refractor and an Alt-Az Mounted Reflector

NASA Astrophysics Data System (ADS)

Frey, Thomas G.; Coombs, Lee C.

2012-07-01

Eight double stars with separations between 13 and 48 arc seconds were studied. Their separations and position angles were measured using an equatorial mounted refractor and and alt-az mounted reflector. A 2x Barlow lens was used along with a Celestron Micro Guide eyepiece to magnify the separation. Comparison of the possible effect of magnitude difference on the separation and position angle measurements was investigated.

Crowdsourced Smart Cities versus Corporate Smart Cities

NASA Astrophysics Data System (ADS)

Alizadeh, Tooran

2018-05-01

Considering the speedy growth of smart-city promises and practices, there is an urgent need to take a critical approach and offer an integrated vision for an otherwise fragmented and sectoral concept. In particular, the literature warns about a critical deficit around the theorization of the smart city because discussions of relevant smart city theories or frameworks are few and fall short of offering alternative practical resolutions to the dominant discourse. In developing a response to such a deficit, this paper takes up the challenge to broaden theoretical insights into smart cities, by offering a bottom-up understanding of the ‘smart city’ concept with special attention to the potential of passive crowdsourcing based on the ocean of mostly untapped and unutilized available data in the public domain. Crowdsourced smart cities are proposed as an alternative to enable public engagement in smart city debates and decision-making – especially when dealing with global digital corporations.

An AzTEC 1.1-mm survey for ULIRGs in the field of the Galaxy Cluster MS0451.6-0305

NASA Astrophysics Data System (ADS)

Wardlow, J. L.; Smail, Ian; Wilson, G. W.; Yun, M. S.; Coppin, K. E. K.; Cybulski, R.; Geach, J. E.; Ivison, R. J.; Aretxaga, I.; Austermann, J. E.; Edge, A. C.; Fazio, G. G.; Huang, J.; Hughes, D. H.; Kodama, T.; Kang, Y.; Kim, S.; Mauskopf, P. D.; Perera, T. A.; Scott, K. S.

2010-02-01

We have undertaken a deep (σ ~ 1.1 mJy) 1.1-mm survey of the z = 0.54 cluster MS0451.6-0305 using the AzTEC camera on the James Clerk Maxwell Telescope. We detect 36 sources with signal-to-noise ratio (S/N) >= 3.5 in the central 0.10 deg2 and present the AzTEC map, catalogue and number counts. We identify counterparts to 18 sources (50 per cent) using radio, mid-infrared, Spitzer InfraRed Array Camera (IRAC) and Submillimetre Array data. Optical, near- and mid-infrared spectral energy distributions are compiled for the 14 of these galaxies with detectable counterparts, which are expected to contain all likely cluster members. We then use photometric redshifts and colour selection to separate background galaxies from potential cluster members and test the reliability of this technique using archival observations of submillimetre galaxies. We find two potential MS0451-03 members, which, if they are both cluster galaxies, have a total star formation rate (SFR) of ~100Msolaryr-1 - a significant fraction of the combined SFR of all the other galaxies in MS0451-03. We also examine the stacked rest-frame mid-infrared, millimetre and radio emission of cluster members below our AzTEC detection limit, and find that the SFRs of mid-IR-selected galaxies in the cluster and redshift-matched field populations are comparable. In contrast, the average SFR of the morphologically classified late-type cluster population is nearly three times less than the corresponding redshift-matched field galaxies. This suggests that these galaxies may be in the process of being transformed on the red sequence by the cluster environment. Our survey demonstrates that although the environment of MS0451-03 appears to suppress star formation in late-type galaxies, it can support active, dust-obscured mid-IR galaxies and potentially millimetre-detected LIRGs.

Influences of die channel angles on microstructures and wear behaviors of AZ61 wrought magnesium alloy fabricated by extrusion-shear process

NASA Astrophysics Data System (ADS)

Hu, Hong-J.; Sun, Z.; Ou, Z.-W.

2016-12-01

Extrusion-shear (ES) process for magnesium alloy is a newly developed plastic deformation process, and ES process combines direct extrusion and two steps of ECAE (equal channel angular extrusion). To investigate the effects of the die channel angles on the microstructures and wear behaviors of AZ61 wrought magnesium alloy, the samples used in this study were fabricated by ES process with different die channel angles (120° and 135°). The microstructures of the samples were characterized by optical microscopy (OM), X-ray diffraction (XRD) and (SEM). The cumulative strains in the ES process were predicted by approaches of numerical simulation and theoretical calculation. To characterize the wear resistance of the samples, pin-on-disk tests under dry sliding conditions with various normal loads and reciprocating frequencies were conducted. To define the wear mechanisms of AZ61 magnesium alloy, the worn surfaces after wear tests were analyzed by SEM and energy-dispersive X-ray spectrometer (EDS). Based on the results obtained, die channel angles have significant influences on the grain refinements and wear behaviors of the samples. Decreasing channel angles of the ES die will not only refine the microstructures of magnesium alloys effectively and improve their harnesses, but also improve their wear resistance as decreasing channel angles results in higher friction coefficients and wear rates. With the increase in applied loads and frequencies, wear mechanisms change from mild wear (adhesion, abrasion and oxidation) to severe wear (delamination, plastic deformation and melting). In summary, the wear resistance of ES-processed AZ61 magnesium alloy could be improved by decreasing channel angles of ES dies.

Is a healthy city also an age-friendly city?

PubMed

Jackisch, Josephine; Zamaro, Gianna; Green, Geoff; Huber, Manfred

2015-06-01

Healthy Ageing is an important focus of the European Healthy Cities Network and has been supported by WHO since 2003 as a key strategic topic, since 2010 in cooperation with the Global Network of Age-friendly Cities and Communities. Based on the methodology of realist evaluation, this article synthesizes qualitative evidence from 33 structured case studies (CS) from 32 WHO European Healthy Cities, 72 annual reports from Network cities and 71 quantitative responses to a General Evaluation Questionnaire. City cases are assigned to three clusters containing the eight domains of an age-friendly city proposed by WHO's Global Age-friendly City Guide published in 2007. The analysis of city's practice and efforts in this article takes stock of how cities have developed the institutional prerequisites and processes necessary for implementing age-friendly strategies, programmes and projects. A content analysis of the CS maps activities across age-friendly domains and illustrates how cities contribute to improving the social and physical environments of older people and enhance the health and social services provided by municipalities and their partners. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Damage and Failure Analysis of AZ31 Alloy Sheet in Warm Stamping Processes

NASA Astrophysics Data System (ADS)

Zhao, P. J.; Chen, Z. H.; Dong, C. F.

2016-07-01

In this study, a combined experimental-numerical investigation on the failure of AZ31 Mg alloy sheet in the warm stamping process was carried out based on modified GTN damage model which integrated Yld2000 anisotropic yield criterion. The constitutive equations of material were implemented into a VUMAT subroutine for solver ABAQUS/Explicit and applied to the formability analysis of mobile phone shell. The morphology near the crack area was observed using SEM, and the anisotropic damage evolution at various temperatures was simulated. The distributions of plastic strain, damage evolution, thickness, and fracture initiation obtained from FE simulation were analyzed. The corresponding forming limit diagrams were worked out, and the comparison with the experimental data showed a good agreement.

Education Cities

ERIC Educational Resources Information Center

Shaked, Haim

2014-01-01

In recent years, several cities in Israel have labeled themselves "Education Cities," concentrating on education as their central theme. Employing qualitative techniques, this article aims to describe, define, and conceptualize this phenomenon as it is being realized in three such cities. Findings show that Education Cities differ from…

Numerical Assessment of the Role of Slip and Twinning in Magnesium Alloy AZ31B During Loading Path Reversal

NASA Astrophysics Data System (ADS)

Wang, Huamiao; Wu, Peidong; Wang, Jian

2015-07-01

Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC-TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension-compression-tension along rolling direction, (2) tension-compression-tension along transverse direction, (3) compression-tension-compression along rolling direction, and (4) compression-tension-compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimental observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Such significant effect is mainly ascribed to the activity of twinning and detwinning.

Fiber Laser Welding-Brazing Characteristics of Dissimilar Metals AZ31B Mg Alloys to Copper with Mg-Based Filler

NASA Astrophysics Data System (ADS)

Zhao, Xiaoye; Tan, Caiwang; Meng, Shenghao; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai

2018-03-01

Fiber laser welding-brazing of 1-mm-thick AZ31B Mg alloys to 1.5-mm-thick copper (T2) with Mg-based filler was performed in a lap configuration. The weld appearance, interfacial microstructure and mechanical properties were investigated with different heat inputs. The results indicated that processing windows for optimizing appropriate welding parameters were relatively narrow in this case. Visually acceptable joints with certain strength were achieved at appropriate welding parameters. The maximum tensile-shear fracture load of laser-welded-brazed Mg/Cu joint could reach 1730 N at the laser power of 1200 W, representing 64.1% joint efficiency relative to AZ31Mg base metal. The eutectic structure (α-Mg + Mg2Cu) and Mg-Cu intermetallic compound was observed at the Mg/Cu interface, and Mg-Al-Cu ternary intermetallic compound were identified between intermetallics and eutectic structure at high heat input. All the joints fractured at the Mg-Cu interface. However, the fracture mode was found to differ. For laser power of 1200 W, the surface was characterized by tearing edge, while that with poor joint strength was almost dominated by smooth surface or flat tear pattern.

Influence of exposure differences on city-to-city heterogeneity ...

EPA Pesticide Factsheets

Multi-city population-based epidemiological studies have observed heterogeneity between city-specific fine particulate matter (PM2.5)-mortality effect estimates. These studies typically use ambient monitoring data as a surrogate for exposure leading to potential exposure misclassification. The level of exposure misclassification can differ by city affecting the observed health effect estimate. The objective of this analysis is to evaluate whether previously developed residential infiltration-based city clusters can explain city-to-city heterogeneity in PM2.5 mortality risk estimates. In a prior paper 94 cities were clustered based on residential infiltration factors (e.g. home age/size, prevalence of air conditioning (AC)), resulting in 5 clusters. For this analysis, the association between PM2.5 and all-cause mortality was first determined in 77 cities across the United States for 2001–2005. Next, a second stage analysis was conducted evaluating the influence of cluster assignment on heterogeneity in the risk estimates. Associations between a 2-day (lag 0–1 days) moving average of PM2.5 concentrations and non-accidental mortality were determined for each city. Estimated effects ranged from −3.2 to 5.1% with a pooled estimate of 0.33% (95% CI: 0.13, 0.53) increase in mortality per 10 μg/m3 increase in PM2.5. The second stage analysis determined that cluster assignment was marginally significant in explaining the city-to-city heterogeneity. The health effe

First 'Rauisuchian' archosaur (Pseudosuchia, Loricata) for the Middle Triassic Santacruzodon assemblage zone (Santa Maria Supersequence), Rio Grande do Sul State, Brazil.

PubMed

Lacerda, Marcel B; Schultz, Cesar L; Bertoni-Machado, Cristina

2015-01-01

The 'Rauisuchia' are a group of Triassic pseudosuchian archosaurs that displayed a near worldwide distribution. In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes). Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei. Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis.

Structure and Mechanical Properties of Friction Stir Weld Joints of Magnesium Alloy AZ31

NASA Astrophysics Data System (ADS)

Nagasawa, T.; Otsuka, M.; Yokota, T.; Ueki, T.

The applicability of friction stir welding to hot rolled sheet of commercial magnesium alloy AZ31 plates has been investigated. Friction stir weld joint showed mechanical strength comparable to that of base material, though the ductility remained at one half of that of the latter. The results are consistent with the microstructure which is characterized by a fine grained bond layer bounded by-intermediate grained base metals. It is found that both anodizing treatment and insertion of aluminum foil between batting faces do not degrade the joint properties at all. The results suggest that friction stir welding can be potentially applied to magnesium alloy.

Mosquito Avoidance Practices and Knowledge of Arboviral Diseases in Cities with Differing Recent History of Disease

PubMed Central

Haenchen, Steven D.; Hayden, Mary H.; Dickinson, Katherine L.; Walker, Kathleen; Jacobs, Elizabeth E.; Brown, Heidi E.; Gunn, Jayleen K. L.; Kohler, Lindsay N.; Ernst, Kacey C.

2016-01-01

As the range of dengue virus (DENV) transmission expands, an understanding of community uptake of prevention and control strategies is needed both in geographic areas where the virus has recently been circulating and in areas with the potential for DENV introduction. Personal protective behaviors such as the use of mosquito repellent to limit human–vector contact and the reduction of vector density through elimination of oviposition sites are the primary control methods for Aedes aegypti, the main vector of DENV. Here, we examined personal mosquito control measures taken by individuals in Key West, FL, in 2012, which had experienced a recent outbreak of DENV, and Tucson, AZ, which has a high potential for introduction but has not yet experienced autochthonous transmission. In both cities, there was a positive association between the numbers of mosquitoes noticed outdoors and the overall number of avoidance behaviors, use of repellent, and removal of standing water. Increased awareness and perceived risk of DENV were associated with increases in one of the most effective household prevention behaviors, removal of standing water, but only in Key West. PMID:27527634

300 Cities - An Exploration in Characterizing US Cities

DTIC Science & Technology

2008-06-01

10 . SPONSOR/MONITOR’S ACRONYM(S) 11. SPONSOR/MONITOR’S REPORT NUMBER(S) 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release...divided into PMSA’s the entire area becomes a CMSA. Metro areas that are not subdivided are designated MSA’s. [ 10 ] (Page 2) 300 Cities CMU-ISR-08-122...considering the general population. 300 Cities CMU-ISR-08-122 - 10 - CASOS Report Figure 2: City Unique Diversity. Percent of city population composed of

The Role of Trans Tensional Structures and Lake Mead Reservoir in Groundwater Flow in Black Canyon, Lake Mead National Recreation Area, NV-AZ

NASA Astrophysics Data System (ADS)

Justet, L.; Beard, S.

2010-12-01

Hot springs and seeps discharging into Black Canyon (BC) along the Colorado River in north Colorado River Valley (CRV) support endemic riparian ecosystems in the Lake Mead National Recreation Area. Increases in groundwater development in southern NV and northwestern AZ may impact spring discharge. Sources of spring discharge in BC were evaluated using geochemical methods. Kinematic analysis and geologic mapping of structures associated with BC springs were used to evaluate structural controls on groundwater flow in BC. Geochemical analysis indicates groundwater discharge near Hoover Dam (HD) and along the faulted edge of the Boulder City Pluton is derived from Lake Mead, high δ87Sr Proterozoic or Tertiary crystalline rock and, possibly, Tertiary sedimentary rock. Reducing conditions indicated by 234U/238U and δ34S concentrations suggest the groundwater is confined and/or derived from greater depths while carbon isotopes indicate the groundwater is old. Lighter δD and δO-18, modern tritium concentrations, post-Dam U disequilibrium ages, and occurrence of anthropogenic perchlorate support the presence of a young Lake Mead component. South of the pluton, the Lake Mead component is absent. More oxidizing conditions in this part of BC, indicated by the U and S isotope concentrations, suggest the groundwater is less confined and/or derived from shallower depths compared to groundwater discharging near HD. Older apparent groundwater ages and heavier δD and δO-18 values south of the pluton indicate slower flow paths from a lower elevation or latitude source. Clarifying the nature of groundwater flow in eastern NV, the analyses indicate that hydraulic connection between the regional carbonate aquifer and BC is unlikely. Instead, the data indicate sources of BC springs are derived relatively locally in CRV and, possibly, south Lake Mead Valley. Results of the geologic and kinematic analyses indicate faults that formed from the interaction of E-W extension related to

Grain size dependence of dynamic mechanical behavior of AZ31B magnesium alloy sheet under compressive shock loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Asgari, H., E-mail: hamed.asgari@usask.ca; Odeshi, A.G.; Szpunar, J.A.

2015-08-15

The effects of grain size on the dynamic deformation behavior of rolled AZ31B alloy at high strain rates were investigated. Rolled AZ31B alloy samples with grain sizes of 6, 18 and 37 μm, were subjected to shock loading tests using Split Hopkinson Pressure Bar at room temperature and at a strain rate of 1100 s{sup −} {sup 1}. It was found that a double-peak basal texture formed in the shock loaded samples. The strength and ductility of the alloy under the high strain-rate compressive loading increased with decreasing grain size. However, twinning fraction and strain hardening rate were found tomore » decrease with decreasing grain size. In addition, orientation imaging microscopy showed a higher contribution of double and contraction twins in the deformation process of the coarse-grained samples. Using transmission electron microscopy, pyramidal dislocations were detected in the shock loaded sample, proving the activation of pyramidal slip system under dynamic impact loading. - Highlights: • A double-peak basal texture developed in all shock loaded samples. • Both strength and ductility increased with decreasing grain size. • Twinning fraction and strain hardening rate decreased with decreasing grain size. • ‘g.b’ analysis confirmed the presence of dislocations in shock loaded alloy.« less

AzTEC half square degree survey of the SHADES fields - I. Maps, catalogues and source counts

NASA Astrophysics Data System (ADS)

Austermann, J. E.; Dunlop, J. S.; Perera, T. A.; Scott, K. S.; Wilson, G. W.; Aretxaga, I.; Hughes, D. H.; Almaini, O.; Chapin, E. L.; Chapman, S. C.; Cirasuolo, M.; Clements, D. L.; Coppin, K. E. K.; Dunne, L.; Dye, S.; Eales, S. A.; Egami, E.; Farrah, D.; Ferrusca, D.; Flynn, S.; Haig, D.; Halpern, M.; Ibar, E.; Ivison, R. J.; van Kampen, E.; Kang, Y.; Kim, S.; Lacey, C.; Lowenthal, J. D.; Mauskopf, P. D.; McLure, R. J.; Mortier, A. M. J.; Negrello, M.; Oliver, S.; Peacock, J. A.; Pope, A.; Rawlings, S.; Rieke, G.; Roseboom, I.; Rowan-Robinson, M.; Scott, D.; Serjeant, S.; Smail, I.; Swinbank, A. M.; Stevens, J. A.; Velazquez, M.; Wagg, J.; Yun, M. S.

2010-01-01

We present the first results from the largest deep extragalactic mm-wavelength survey undertaken to date. These results are derived from maps covering over 0.7deg2, made at λ = 1.1mm, using the AzTEC continuum camera mounted on the James Clerk Maxwell Telescope. The maps were made in the two fields originally targeted at λ = 850μm with the Submillimetre Common-User Bolometer Array (SCUBA) in the SCUBA Half-Degree Extragalactic Survey (SHADES) project, namely the Lockman Hole East (mapped to a depth of 0.9-1.3 mJy rms) and the Subaru/XMM-Newton Deep Field (mapped to a depth of 1.0-1.7 mJy rms). The wealth of existing and forthcoming deep multifrequency data in these two fields will allow the bright mm source population revealed by these new wide-area 1.1mm images to be explored in detail in subsequent papers. Here, we present the maps themselves, a catalogue of 114 high-significance submillimetre galaxy detections, and a thorough statistical analysis leading to the most robust determination to date of the 1.1mm source number counts. These new maps, covering an area nearly three times greater than the SCUBA SHADES maps, currently provide the largest sample of cosmological volumes of the high-redshift Universe in the mm or sub-mm. Through careful comparison, we find that both the Cosmic Evolution Survey (COSMOS) and the Great Observatories Origins Deep Survey (GOODS) North fields, also imaged with AzTEC, contain an excess of mm sources over the new 1.1mm source-count baseline established here. In particular, our new AzTEC/SHADES results indicate that very luminous high-redshift dust enshrouded starbursts (S1.1mm > 3mJy) are 25-50 per cent less common than would have been inferred from these smaller surveys, thus highlighting the potential roles of cosmic variance and clustering in such measurements. We compare number count predictions from recent models of the evolving mm/sub-mm source population to these sub-mm bright galaxy surveys, which provide important

Using a weight of evidence approach for assessing ...

EPA Pesticide Factsheets

The Ottawa River lies in extreme northwest Ohio, flowing into Lake Erie’s western basin at the City of Toledo. The Ottawa River is a component of the Maumee River AOC as defined by the International Commission. The Ottawa River is approximately 45 miles long; however, the 2009-2010 remediation project took place in the lower 8.8 miles of the river where urban and industrial activities have had a detrimental impact on the river as a beneficial resource. The primary COCs at the site are PCBs, PAHs, inorganics (principally lead), and oil and grease. Approximately 260,000 yd3 of contaminated sediments were removed from the study reach. Removal was accomplished through dredging in targeted areas within 3 reaches of the river where COCs exceeded a target level. The overall objectives of this research effort are twofold: 1) Develop chemical, physical, and biological tools and approaches to evaluate the quantity and sources of post-dredge residuals; and 2) Develop an approach to quantify remedial effectiveness using chemical, physical, and biological tools and approaches. This presentation will focus on 2 of the biological tools: assessing response of various trophic levels to changes in tissue concentrations of PCBs and PAHs and DNA damage in Brown Bullheads. From 2009-2013, pre- and post-remedy sampling of fishes representative of different trophic levels was conducted via electroshocking and fyke net sampling. Fishes collected were largemouth bass, brown bullhead,

Deep 1.1 mm-wavelength imaging of the GOODS-S field by AzTEC/ASTE - II. Redshift distribution and nature of the submillimetre galaxy population

NASA Astrophysics Data System (ADS)

Yun, Min S.; Scott, K. S.; Guo, Yicheng; Aretxaga, I.; Giavalisco, M.; Austermann, J. E.; Capak, P.; Chen, Yuxi; Ezawa, H.; Hatsukade, B.; Hughes, D. H.; Iono, D.; Johnson, S.; Kawabe, R.; Kohno, K.; Lowenthal, J.; Miller, N.; Morrison, G.; Oshima, T.; Perera, T. A.; Salvato, M.; Silverman, J.; Tamura, Y.; Williams, C. C.; Wilson, G. W.

2012-02-01

We report the results of the counterpart identification and a detailed analysis of the physical properties of the 48 sources discovered in our deep 1.1-mm wavelength imaging survey of the Great Observatories Origins Deep Survey-South (GOODS-S) field using the AzTEC instrument on the Atacama Submillimeter Telescope Experiment. One or more robust or tentative counterpart candidate is found for 27 and 14 AzTEC sources, respectively, by employing deep radio continuum, Spitzer/Multiband Imaging Photometer for Spitzer and Infrared Array Camera, and Large APEX Bolometer Camera 870 μm data. Five of the sources (10 per cent) have two robust counterparts each, supporting the idea that these galaxies are strongly clustered and/or heavily confused. Photometric redshifts and star formation rates (SFRs) are derived by analysing ultraviolet(UV)-to-optical and infrared(IR)-to-radio spectral energy distributions (SEDs). The median redshift of zmed˜ 2.6 is similar to other earlier estimates, but we show that 80 per cent of the AzTEC-GOODS sources are at z≥ 2, with a significant high-redshift tail (20 per cent at z≥ 3.3). Rest-frame UV and optical properties of AzTEC sources are extremely diverse, spanning 10 mag in the i- and K-band photometry (a factor of 104 in flux density) with median values of i= 25.3 and K= 22.6 and a broad range of red colour (i-K= 0-6) with an average value of i-K≈ 3. These AzTEC sources are some of the most luminous galaxies in the rest-frame optical bands at z≥ 2, with inferred stellar masses M*= (1-30) × 1010 M⊙ and UV-derived SFRs of SFRUV≳ 101-3 M⊙ yr-1. The IR-derived SFR, 200-2000 M⊙ yr-1, is independent of z or M*. The resulting specific star formation rates, SSFR ≈ 1-100 Gyr-1, are 10-100 times higher than similar mass galaxies at z= 0, and they extend the previously observed rapid rise in the SSFR with redshift to z= 2-5. These galaxies have a SFR high enough to have built up their entire stellar mass within their Hubble time

Laser surface structuring of AZ31 Mg alloy for controlled wettability.

PubMed

Gökhan Demir, Ali; Furlan, Valentina; Lecis, Nora; Previtali, Barbara

2014-06-01

Structured surfaces exhibit functional properties that can enhance the performance of a bioimplant in terms of biocompatibility, adhesion, or corrosion behavior. In order to tailor the surface property, chemical and physical methods can be used in a sequence of many steps. On the other hand, laser surface processing can provide a single step solution to achieve the designated surface function with the use of simpler equipment and high repeatability. This work provides the details on the surface structuring of AZ31, a biocompatible and biodegradable Mg alloy, by a single-step laser surface structuring based on remelting. The surfaces are characterized in terms of topography, chemistry, and physical integrity, as well as the effective change in the surface wetting behavior is demonstrated. The results imply a great potential in local or complete surface structuring of medical implants for functionalization by the flexible positioning of the laser beam.

Low-Cycle Fatigue Behavior of Die-Cast Mg Alloy AZ91

NASA Astrophysics Data System (ADS)

Rettberg, Luke; Anderson, Warwick; Jones, J. Wayne

An investigation has been conducted on the influence of microstructure and artificial aging response (T6) on the low-cycle fatigue behavior of super vacuum die-cast (SVDC) AZ91. Fatigue lifetimes were determined from total strain-controlled fatigue tests for strain amplitudes of 0.2%, 0.4% and 0.6%, under fully reversed loading at a frequency of 5 Hz. Cyclic stress-strain behavior was determined using incremental step test (IST) methods. Two locations in a prototype casting with different thicknesses and, therefore, solidification rates, microstructure and porosity, were examined. In general., at all total strain amplitudes fatigue life was unaffected by microstructure refinement and was attributed to significant levels of porosity. Cyclic softening and a subsequent increased cyclic hardening rate, compared to monotonic tests, were observed, independent of microstructure. These results, fractography and damage accumulation processes, determined from metallographic sectioning, are discussed.

An Elevated-Temperature Tension-Compression Test and Its Application to Magnesium AZ31B

NASA Astrophysics Data System (ADS)

Piao, Kun

Many metals, particularly ones with HCP crystal structures, undergo deformation by combinations of twinning and slip, the proportion of which depends on variables such as temperature and strain rate. Typical techniques to reveal such mechanisms rely on metallography, x-ray diffraction, or electron optics. Simpler, faster, less expensive mechanical tests were developed in the current work and applied to Mg AZ31B. An apparatus was designed, simulated, optimized, and constructed to enable the large-strain, continuous tension/compression testing of sheet materials at elevated temperature. Thermal and mechanical FE analyses were used to locate cartridge heaters, thus enabling the attainment of temperatures up to 350°C within 15 minutes of start-up, and ensuring temperature uniformity throughout the gage length within 8°C. The low-cost device also makes isothermal testing possible at strain rates higher than corresponding tests in air. Analysis was carried out to predict the attainable compressive strains using novel finite element (FE) modeling and a single parameter characteristic of the machine and fixtures. The limits of compressive strain vary primarily with the material thickness and the applied-side-force-to-material-strength ratio. Predictions for a range of sheet alloys with measured buckling strains from -0.04 to -0.17 agreed within a standard deviation of 0.025 (0.015 excluding one material that was not initially flat). In order to demonstrate the utility of the new method, several sheet materials were tested over a range of temperatures. Some of the data obtained is the first of its kind. Magnesium AZ31B sheets were tested at temperatures up to 250°C with strain rate of 0.001/s. The inflected stress-strain curve observed in compression at room temperature disappeared between 125°C and 150°C, corresponding to the suppression of twinning, and suggesting a simple method for identifying the deformation mechanism transition temperature. The temperature

The fish community of a small impoundment in upstate New York

USGS Publications Warehouse

McCoy, C. Mead; Madenjian, Charles P.; Adams, Jean V.; Harman, Willard N.

2001-01-01

Moe Pond is a dimictic impoundment with surface area of 15.6 ha, a mean depth of 1.8 m, and an unexploited fish community of only two species: brown bullhead (Ameiurus nebulosus) and golden shiner (Notemigonus crysoleucas). The age-1 and older brown bullhead population was estimated to be 4,057 individuals, based on the Schnabel capture-recapture method of population estimation. Density and biomass were respectively estimated at 260 individuals/ha and 13 kg/ha. Annual survival rate of age-2 through age-5 brown bullheads was estimated at 48%. The golden shiner length-frequency distribution was unimodal with modal length of 80 mm and maximum total length of 115 m. The golden shiner population estimate was 7,154 individuals, based on seven beach seine haul replicate samples; the density and biomass were 686 shiners/ha and 5 kg/ha, respectively. This study provides an information baseline that may be useful in understanding food web interactions and whole-pond nutrient flux.

Sparse Feature Selection Identifies H2A.Z as a Novel, Pattern-Specific Biomarker for Asymmetrically Self-Renewing Distributed Stem Cells

PubMed Central

Huh, Yang Hoon; Noh, Minsoo; Burden, Frank R.; Chen, Jennifer C.; Winkler, David A.; Sherley, James L.

2015-01-01

There is a long-standing unmet clinical need for biomarkers with high specificity for distributed stem cells (DSCs) in tissues, or for use in diagnostic and therapeutic cell preparations (e.g., bone marrow). Although DSCs are essential for tissue maintenance and repair, accurate determination of their numbers for medical applications has been problematic. Previous searches for biomarkers expressed specifically in DSCs were hampered by difficulty obtaining pure DSCs and by the challenges in mining complex molecular expression data. To identify DSC such useful and specific biomarkers, we combined a novel sparse feature selection method with combinatorial molecular expression data focused on asymmetric self-renewal, a conspicuous property of DSCs. The analysis identified reduced expression of the histone H2A variant H2A.Z as a superior molecular discriminator for DSC asymmetric self-renewal. Subsequent molecular expression studies showed H2A.Z to be a novel “pattern-specific biomarker” for asymmetrically self-renewing cells with sufficient specificity to count asymmetrically self-renewing DSCs in vitro and potentially in situ. PMID:25636161

Biofunctional composite coating architectures based on polycaprolactone and nanohydroxyapatite for controlled corrosion activity and enhanced biocompatibility of magnesium AZ31 alloy.

PubMed

Zomorodian, A; Garcia, M P; Moura E Silva, T; Fernandes, J C S; Fernandes, M H; Montemor, M F

2015-03-01

In this work a biofunctional composite coating architecture for controlled corrosion activity and enhanced cellular adhesion of AZ31 Mg alloys is proposed. The composite coating consists of a polycaprolactone (PCL) matrix modified with nanohydroxyapatite (HA) applied over a nanometric layer of polyetherimide (PEI). The protective properties of the coating were studied by electrochemical impedance spectroscopy (EIS), a non-disturbing technique, and the coating morphology was investigated by field emission scanning electron microscopy (FE-SEM). The results show that the composite coating protects the AZ31 substrate. The barrier properties of the coating can be optimized by changing the PCL concentration. The presence of nanohydroxyapatite particles influences the coating morphology and decreases the corrosion resistance. The biocompatibility was assessed by studying the response of osteoblastic cells on coated samples through resazurin assay, confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). The results show that the polycaprolactone to hydroxyapatite ratio affects the cell behavior and that the presence of hydroxyapatite induces high osteoblastic differentiation. Copyright © 2014 Elsevier B.V. All rights reserved.

78 FR 23866 - Safety Zone; Crescent City 4th of July Fireworks; Crescent City Harbor, Crescent City, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-23

...-AA00 Safety Zone; Crescent City 4th of July Fireworks; Crescent City Harbor, Crescent City, CA AGENCY... a temporary safety zone in the navigable waters near Crescent City, CA in support of the Crescent City 4th of July Fireworks on July 4, 2013. This safety zone is necessary to ensure the safety of...

City personification as problem solving to strengthen the wholeness of the city: study case in Serui city, Papua

NASA Astrophysics Data System (ADS)

Hardine, Y. R. I.; Herlily

2018-03-01

Serui City in Papua Province has many unique characters and must be maintained for the sake of the continuity of its identity. However, this city still lacks the facility and depend on other areas. Accordingly, it becomes vulnerable. The wholeness of the city is not just by having strong character but also having strength regarding vitality. The loss of it can affect the character and even eliminate it. Cities and people have many similarities regarding character and vitality. Therefore, there is a chance to solve the problems in the city using the similar approach to treat the human. We called city personification methods as problem-solving to the city. It means that we treat the city as a human being so that the problem can be solved as the human’s treatment. The personification of this city is conducted because of the many treatments that have proven effective in humans and may also be powerful to manifest in city. The personification makes the design will only focus on the particular networks and not on the whole “body,” remain in the hope for strengthening (maintain and improve) the quality of wholeness (character and vitality) city which in this case is Serui.

An AzTEC 1.1mm Survey of a Highly-biased Extragalactic Field Tracing Accelerated Galaxy Formation at z 3.8 towards 4C41.17

NASA Astrophysics Data System (ADS)

Hughes, David; Ade, P. A.; Aretxaga, I.; Austermann, J.; Bock, J. J.; Dunlop, J.; Gaztanagal, E.; Ivison, R.; Kang, Y.; Kim, S.; Lowenthal, J.; Mauskopf, P.; Montana, A.; Plionis, M.; Scott, K.; Smail, I.; Stevens, J.; Wagg, J.; Wilson, G.; Yun, M.

2006-12-01

Aztec has recently conducted a sensitive, wide-area (300 sq. arcmin's) continuum survey at 1.1mm using the 15-m James Clerk Maxwell Telescope towards 4C41.17, a powerful high-redshift (z 3.8) radio galaxy. These Aztec data, which cover an area >40 times larger than our previous SCUBA survey, reveal a significant over-density of luminous, massive dust-enshrouded galaxies, compared to the results from lower-redshift blank-field sub-mm surveys. One natural interpretation of these new AzTEC data is that the over-density is tracing a large (5 x 5 Mpc) "proto-cluster" structure at z 3.8 associated with the environment of 4C41.17, within which the formation of ultra-luminous starburst galaxies (with rest-frame FIR luminosities >5 x 10^12 Lsun or SFRs > 500 Msun/yr) is taking place at an accelerated rate. Proving the physical association of these massive optically-faint starbursts with the environment of this high-z AGN, and not with the blank-field sub-mm population, for which 50% of the population lies at 1.9 < z < 2.9, remains an outstanding problem. In this presentation we will describe the AzTEC survey, the empirical evidence for this protocluster structure in the early universe, and the planned multi-wavelength follow-up observations of the brightest AzTEC sources towards 4C41.17 that may demonstrate that we are witnessing accelerated galaxy formation, via an increased rate of merging gas-rich galaxies within a rapidly-developing gravitational potential. AzTEC is one of the suite of instruments destined for the 50-m Large Millimeter Telescope (LMT). We will conclude this presentation with a summary of future LMT observations that will trace the evolution of obscured starformation in the dynamic environments towards a significant sample of intermediate and high-z powerful AGN with greater sensitivity and spatial resolution.

Box City Curriculum.

ERIC Educational Resources Information Center

Center for Understanding the Built Environment, Prairie Village, KS.

This curriculum packet contains two lesson plans about cities and architecture intended for use with students in upper elementary grades and middle schools. The first lesson plan, "City People, City Stories" (Jan Ham), states that understanding architecture and cities must begin with an understanding of the people of the city. The children create…

Rethinking GIS Towards The Vision Of Smart Cities Through CityGML

NASA Astrophysics Data System (ADS)

Guney, C.

2016-10-01

Smart cities present a substantial growth opportunity in the coming years. The role of GIS in the smart city ecosystem is to integrate different data acquired by sensors in real time and provide better decisions, more efficiency and improved collaboration. Semantically enriched vision of GIS will help evolve smart cities into tomorrow's much smarter cities since geospatial/location data and applications may be recognized as a key ingredient of smart city vision. However, it is need for the Geospatial Information communities to debate on "Is 3D Web and mobile GIS technology ready for smart cities?" This research places an emphasis on the challenges of virtual 3D city models on the road to smarter cities.

Investigation of the gas-jet ejector in KamAZ trucks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shkret, L.Y.; Berezea, A.I.; Lobkov, A.N.

1984-03-01

This article considers the possibility of using gas-jet vacuum pumps in tank trucks for transporting liquids (water) at drilling sites. The discharge system of the KamAZ trucks can be reliably sealed by an engine brake, an important prerequisite of reliable operation of a gas-jet ejector that is switched on when the tank is being filled. The ejector consists of a housing, a Laval nozzle, a front wall with cylindrical neck, a tin-plate diffuser, an air supply pipe, and a flange for attaching the ejector to the flange of the exhaust muffler of the truck. The gas-jet ejectors are driven bymore » the exhaust gas (EG) of the trucks. The dependences of the EG flow rate, fuel expenditure, EG temperature ahead of the ejector, and the rotational frequency of the engine crankshaft on the diameter at different EG pressures. It is recommended that gas-jet ejectors be used on series produced tank trucks instead of rotary vacuum pumps with mechanical drive.« less

Microstructure and interfacial reactions of soldering magnesium alloy AZ31B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu Liming, E-mail: liulm@dlut.edu.cn; Wu Zhonghui

2010-01-15

In this paper, economic and innoxious solder alloys with low melting temperature were designed for AZ31B. Their chemical composition and relevant parameters were investigated for a high-performance structure of bonding region. Results of microstructure observation showed that Zn-enriched phases disappeared and {alpha}-Mg existed in the joints in the form of coarse dendrites by increasing the concentration of Mg in the solder alloys. Water cooling with a high cooling rate was adopted in experiments. Experimental research showed that high cooling rate restricted the grains of {alpha}-Mg as the equiaxed dendrites, which was about 1/5 of the coarse dendrite but their numbermore » was more than 40-50 times. Both morphology with typical fracture and the analysis on X-ray diffraction fracture indicated that equiaxed dendrites significantly improved the mechanical property of the joints. Necking phenomenon occurred in the bonding region was in favor of the improvement of joint shear strength.« less

Preparation and corrosion resistance of electroless Ni-P/SiC functionally gradient coatings on AZ91D magnesium alloy

NASA Astrophysics Data System (ADS)

Wang, Hui-Long; Liu, Ling-Yun; Dou, Yong; Zhang, Wen-Zhu; Jiang, Wen-Feng

2013-12-01

In this paper, the protective electroless Ni-P/SiC gradient coatings on AZ91D magnesium alloy substrate were successfully prepared. The prepared Ni-P/SiC gradient coatings were characterized for its microstructure, morphology, microhardness and adhesion to the substrate. The deposition reaction kinetics was investigated and an empirical rate equation for electroless Ni-P/SiC plating on AZ91D magnesium alloy was developed. The anticorrosion properties of the Ni-P/SiC gradient coatings in 3.5 wt.% NaCl solution were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies. The potentiodynamic polarization measurements revealed that the SiC concentration in the bath and heat treatment can influence the corrosion protection performance of electroless deposited Ni-P/SiC gradient coatings. EIS studies indicated that higher charge transfer resistance and slightly lower capacitance values were obtained for Ni-P/SiC gradient coatings compared to Ni-P coatings. The corrosion resistance of the Ni-P/SiC gradient coatings increases initially and decreases afterwards with the sustained increasing of immersion time in the aggressive medium. The electroless Ni-P/SiC gradient coatings can afford better corrosion protection for magnesium alloy substrate compared with Ni-P coatings.

Numerical assessment of the role of slip and twinning in magnesium alloy AZ31B during loading path reversal

DOE PAGES

Wang, Huamiao; Wu, Peidong; Wang, Jian

2015-04-17

Magnesium alloy AZ31B plastically deforms via twinning and slip. Corresponding to the unidirectional nature of twinning, the activity of twinning/detwinning is directly related to loading history and materials texture. Using the elastic viscoplastic self-consistent model implementing with the twinning and detwinning model (EVPSC–TDT), we revisited experimental data of AZ31B sheets under four different strain paths: (1) tension–compression–tension along rolling direction, (2) tension–compression–tension along transverse direction, (3) compression–tension–compression along rolling direction, and (4) compression–tension–compression along transverse direction, and identified the dominant deformation mechanisms with respect to the strain path. We captured plastic deformation behaviors observed in experiments and quantitatively interpreted experimentalmore » observations in terms of the activities of different deformation mechanisms and the evolution of texture. It is found that the in-plane pre-tension has slight effect on the subsequent deformation, and the pre-compression and the reverse tension after compression have significant effect on the subsequent deformation. The inelastic behavior under compressive unloading is found to be insignificant at a small strain level but pronounced at a large strain level. Lastly, such significant effect is mainly ascribed to the activity of twinning and detwinning.« less

78 FR 23869 - Safety Zone; Redwood City 4th of July Fireworks Show; Port of Redwood City, Redwood City, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-23

...-AA00 Safety Zone; Redwood City 4th of July Fireworks Show; Port of Redwood City, Redwood City, CA... establish a temporary safety zone in the navigable waters of the Port of Redwood City near Redwood City, CA in support of the Redwood City 4th of July Fireworks Show on July 4, 2013. This safety zone is...

Medan City: Informality and the Historical Global City

NASA Astrophysics Data System (ADS)

Sudarmadji, N.; Tyaghita, B.; Astuti, P. T.; Etleen, D.

2018-05-01

As projected by UN that two-thirds of Indonesia’s population will live in urban areas by 2050, rapid urbanization is happening in Indonesian cities. Initial research on eight Indonesian Cities (which includes Medan, Jatinegara, Bandung, Surakarta, Yogyakarta, Surabaya, Balikpapan, and Manado) by Tunas Nusa Foundation since 2012 shows that urbanization of each city has happened throughout history creating cultural, economic, and environmental networks that are distinct from one city to another. While the networks remain until today and continuously shapes the urban agglomeration pattern, not all parts of the city could undergo subsequent development that confirms the existing pattern, leading to the creation informality. Nor could it make future planning that comprehends the nature of its integrated urban dynamic beyond its current administrative authority. In this paper, we would like to share our study for Medan, North Sumatra as it shows a portrait of a city with a long relationship to a global network since the Maritime trade era. Medan has become home to many ethnic groups which have sailed and migrated as part of a global economic agenda creating a strong economic network between port cities along the Malacca Strait. The city has kept its role in the global economic network until today, to name a few, becoming the frontier for the Indonesia-Malaysia-Thailand Growth Triangle. While we celebrate Medan’s potential to become a global city with major infrastructure development as well as cultural assets as its advantage in the future, we argue that microscale cohesion supported by government policy in agreed planning documents are fundamental for the city to thrive amidst the challenges it is facing. Yet, these cultural assets, as well as micro scale cohesion in Medan City today, are still undermined. Thus, informality in Medan exists as result of ignorance and marginalization of certain socio-cultural groups, abandoning places and identity, as well as the

First 'Rauisuchian' archosaur (Pseudosuchia, Loricata) for the Middle Triassic Santacruzodon Assemblage Zone (Santa Maria Supersequence), Rio Grande do Sul State, Brazil

PubMed Central

Lacerda, Marcel B.; Schultz, Cesar L.; Bertoni-Machado, Cristina

2015-01-01

The ‘Rauisuchia’ are a group of Triassic pseudosuchian archosaurs that displayed a near worldwide distribution. In Brazil, their fossils are found only in the Santa Maria Formation (Paraná Basin) of the Rio Grande do Sul State, specifically in the Middle Triassic Dinodontosaurus assemblage zone (AZ) and the Late Triassic Hyperodapedon AZ (Rauisuchus tiradentes). Between these two cenozones is the Santacruzodon AZ (Middle Triassic), whose record was, until now, restricted to non-mammalian cynodonts and the proterochampsian Chanaresuchus bonapartei. Here we present the first occurrence of a rauisuchian archosaur for this cenozone, from the Schoenstatt outcrop, located near the city of Santa Cruz do Sul and propose a new species, based on biostratigraphical evidence and a comparative osteological analysis. PMID:25714091

33 CFR 100.911 - Bay City Airshow, Bay City, MI.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Bay City Airshow, Bay City, MI. 100.911 Section 100.911 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.911 Bay City Airshow, Bay City, MI. (a...

33 CFR 100.911 - Bay City Airshow, Bay City, MI.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Bay City Airshow, Bay City, MI. 100.911 Section 100.911 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.911 Bay City Airshow, Bay City, MI. (a...

33 CFR 100.911 - Bay City Airshow, Bay City, MI.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Bay City Airshow, Bay City, MI. 100.911 Section 100.911 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.911 Bay City Airshow, Bay City, MI. (a...

33 CFR 100.911 - Bay City Airshow, Bay City, MI.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bay City Airshow, Bay City, MI. 100.911 Section 100.911 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.911 Bay City Airshow, Bay City, MI. (a...

33 CFR 100.911 - Bay City Airshow, Bay City, MI.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bay City Airshow, Bay City, MI. 100.911 Section 100.911 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY REGATTAS AND MARINE PARADES SAFETY OF LIFE ON NAVIGABLE WATERS § 100.911 Bay City Airshow, Bay City, MI. (a...

Optimization of process factors for self-healing vanadium-based conversion coating on AZ31 magnesium alloy

NASA Astrophysics Data System (ADS)

Li, Kun; Liu, Junyao; Lei, Ting; Xiao, Tao

2015-10-01

A self-healing vanadium-based conversion coating was prepared on AZ31 magnesium alloy. The optimum operating conditions including vanadia solution concentration, pH and treating temperature for obtaining the best corrosion protective vanadia coatings and improved localized corrosion resistance to the magnesium substrate were determined by an orthogonal experiment design. Surface morphology and composition of the resultant conversion coatings were investigated by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS). The self-healing behavior of the coating was investigated by cross-cut immersion test and electrochemical impedance spectroscopy (EIS) measurements in 3.5% NaCl solution.

Micro-FTIR Spectroscopy of Experimentally Shocked Basaltic Andesite (SP Flow, AZ)

NASA Astrophysics Data System (ADS)

Johnson, J. R.; Jaret, S.; Glotch, T. D.; Sims, M.

2017-12-01

As part of an ongoing systematic study of experimental shock transformations in plagioclase using micro-Raman and micro-FTIR thermal infrared hyperspectral imaging and point spectroscopy [1-7], we report new micro-FTIR results on experimentally shocked, fine-grained basaltic andesite from SP Flow (AZ). This sample has relatively high primary glass content and an average plagioclase composition of labradorite/bytownite. The powder propellant gun at the Johnson Space Center was used to conduct the original shock experiments at peak pressures from 15 to 60 GPa [6-8], from which <10 mm fragments were recovered. Polished thin sections were made from portions of these fragments, and micro-FTIR point spectra were collected from 400-4000 cm-1 (2.5-25 µm) using a spot size of 40 x 40 mm at 8 cm-1 spectral sampling. Micro-FTIR hyperspectral maps of thin sections were acquired using the same instrument equipped with a 16 pixel HgCdTe linear array detector to provide spectra between 7000 and 715 cm-1 (1.4-14.0 µm) at 25 µm/pixel and 8 cm-1 spectral sampling (see figure for color composite and band depth images from unshocked sample). Micro-FTIR results show that the unshocked sample is dominated by the glassy matrix (light green in the color composite), with contributions from plagioclase and pyroxene. Initial analyses suggest that the SP Flow samples become dominantly amorphous at relatively low shock pressures, reflective of the high primary glass content and consistent with macro-scale spectra from [7]. Results from additional shock pressures and Raman spectra will be presented at the conference. Future work will include (1) Raman and FTIR analyses of basalt from Grand Falls (AZ), which has minimal primary glass content and relatively higher calcic plagioclase than SP Flow; and (2) comparison of these basalts to results from shocked plagioclase and to similar analyses of naturally shocked samples from Ries and Lonar Craters. [1] Jaret, S. et al., 11th Internat. Geo

(Sub)millimetre interferometric imaging of a sample of COSMOS/AzTEC submillimetre galaxies. III. Environments

NASA Astrophysics Data System (ADS)

Smolčić, V.; Miettinen, O.; Tomičić, N.; Zamorani, G.; Finoguenov, A.; Lemaux, B. C.; Aravena, M.; Capak, P.; Chiang, Y.-K.; Civano, F.; Delvecchio, I.; Ilbert, O.; Jurlin, N.; Karim, A.; Laigle, C.; Le Fèvre, O.; Marchesi, S.; McCracken, H. J.; Riechers, D. A.; Salvato, M.; Schinnerer, E.; Tasca, L.; Toft, S.

2017-01-01

We investigate the environment of 23 submillimetre galaxies (SMGs) drawn from a signal-to-noise (S/N)-limited sample of SMGs originally discovered in the James Clerk Maxwell Telescope (JCMT)/AzTEC 1.1 mm continuum survey of a Cosmic Evolution Survey (COSMOS) subfield and then followed up with the Submillimetre Array and Plateau de Bure Interferometer at 890 μm and 1.3 mm, respectively. These SMGs already have well-defined multiwavelength counterparts and redshifts. We also analyse the environments of four COSMOS SMGs spectroscopically confirmed to lie at redshifts zspec > 4.5, and one at zspec = 2.49 resulting in a total SMG sample size of 28. We search for overdensities using the COSMOS photometric redshifts based on over 30 UV-NIR photometric measurements including the new UltraVISTA data release 2 and Spitzer/SPLASH data, and reaching an accuracy of σΔz/ (1 + z) = 0.0067 (0.0155) at z < 3.5 (>3.5). To identify overdensities we apply the Voronoi tessellation analysis, and estimate the redshift-space overdensity estimator δg as a function of distance from the SMG and/or overdensity centre. We test and validate our approach via simulations, X-ray detected groups or clusters, and spectroscopic verifications using VUDS and zCOSMOS catalogues which show that even with photometric redshifts in the COSMOS field we can efficiently retrieve overdensities out to z ≈ 5. Our results yield that 11 out of 23 (48%) JCMT/AzTEC 1.1 mm SMGs occupy overdense environments. Considering the entire JCMT/AzTEC 1.1 mm S/N ≥ 4 sample and taking the expected fraction of spurious detections into account, this means that 35-61% of the SMGs in the S/N-limited sample occupy overdense environments. We perform an X-ray stacking analysis in the 0.5-2 keV band using a 32″ aperture and our SMG positions, and find statistically significant detections. For our z < 2 subsample we find an average flux of (4.0 ± 0.8) × 10-16 erg s-1 cm-2 and a corresponding total mass of M200 = 2.8 × 1013M�

Twinning behaviors of a rolled AZ31 magnesium alloy under multidirectional loading

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hou, Dewen

The microstructure and texture evolution of an AZ31 magnesium rolled sheet during quasi-static compression at strain rates of 10{sup −3} s{sup −1} has been investigated by in situ electron backscattered diffraction. The influence of the initial and pre-deformed texture on the predominant deformation mechanisms during compression has been examined. It has been found that extensive grain reorientation due to (10 − 12) tensile twinning appeared when compressed along transverse direction. Tensile twin variants were observed under this loading condition, and different variants will cause an effect to the following deformation. Several twinning modes occurred with continuative loading along rolling direction.more » - Highlights: •Twinning behaviors were investigated through in situ multidirectional compressive tests. •Deformation behavior was affected by the twin variants. •Four types of twinning behaviors were observed during deformation process.« less

Microstructural evolution of AZ31 magnesium alloy subjected to sliding friction treatment

NASA Astrophysics Data System (ADS)

Zhang, Wei; Lu, Jinwen; Huo, Wangtu; Zhang, Yusheng; Wei, Q.

2018-06-01

Microstructural evolution and grain refinement mechanism in AZ31 magnesium alloy subjected to sliding friction treatment were investigated by means of transmission electron microscopy. The process of grain refinement was found to involve the following stages: (I) coarse grains were divided into fine twin plates through mechanical twinning; then the twin plates were transformed to lamellae with the accumulation of residual dislocations at the twin boundaries; (II) the lamellae were separated into subgrains with increasing grain boundary misorientation and evolution of high angle boundaries into random boundaries by continuous dynamic recrystallisation (cDRX); (III) the formation of nanograins. The mechanisms for the final stage, the formation of nanograins, can be classified into three types: (i) cDRX; (ii) discontinuous dynamic recrystallisation (dDRX); (iii) a combined mechanism of prior shear-band and subsequent dDRX. Stored strain energy plays an important role in determining deformation mechanisms during plastic deformation.

Chitosan coatings crosslinked with genipin for corrosion protection of AZ31 magnesium alloy sheets.

PubMed

de Y Pozzo, Ludmila; da Conceição, Thiago F; Spinelli, Almir; Scharnagl, Nico; Pires, Alfredo T N

2018-02-01

In this study, coatings of chitosan crosslinked with genipin were prepared on sheets of AZ31 magnesium alloy and their corrosion protection properties were characterized by means of potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The coatings were also characterized by means of FTIR and XPS. It was observed that the crosslinking process decreases the corrosion current and shifts the corrosion potential of the alloy to less negative values. The EIS analysis demonstrated that the crosslinking process increases the maximum impedance after short and long exposure times. The superior performance of the crosslinked coatings is related to a lower degree of swelling, as observed in the swelling tests carried out on free-standing films. Copyright © 2017 Elsevier Ltd. All rights reserved.

Stepwise flow diagram for the development of formulations of non spore-forming bacteria against foliar pathogens: The case of Lysobacter capsici AZ78.

PubMed

Segarra, Guillem; Puopolo, Gerardo; Giovannini, Oscar; Pertot, Ilaria

2015-12-20

The formulation is a significant step in biopesticide development and is an efficient way to obtain consistency in terms of biological control under field conditions. Nonetheless, there is still a lack of information regarding the processes needed to achieve efficient formulation of non spore-forming bacterial biological control agents. In response to this, we propose a flow diagram made up of six steps including selection of growth parameters, checking of minimum shelf life, selection of protective additives, checking that the additives have no adverse effects, validation of the additive mix under field conditions and choosing whether to use additives as co-formulants or tank mix additives. This diagram is intended to provide guidance and decision-making criteria for the formulation of non spore-forming bacterial biological control agents against foliar pathogens. The diagram was then validated by designing an efficient formulation for a Gram-negative bacterium, Lysobacter capsici AZ78, to control grapevine downy mildew caused by Plasmopara viticola. A harvest of 10(10)L. capsici AZ78cellsml(-1) was obtained in a bench top fermenter. The viability of cells decreased by only one order of magnitude after one year of storage at 4°C. The use of a combination of corn steep liquor, lignosulfonate, and polyethyleneglycol in the formulation improved the survival of L. capsici AZ78 cells living on grapevine leaves under field conditions by one order of magnitude. Furthermore, the use of these additives also guaranteed a reduction of 71% in P. viticola attacks. In conclusion, this work presents a straightforward stepwise flow diagram to help researchers develop formulations for biological control agents that are easy to prepare, stable, not phytotoxic and able to protect the microorganims under field conditions. Copyright © 2015 Elsevier B.V. All rights reserved.

26. 'CITY HOSPITAL, BLACKWELL'S ISLAND.' (Source: New York City Department ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

26. 'CITY HOSPITAL, BLACKWELL'S ISLAND.' (Source: New York City Department of Public Finance, Real Estate Owned by the City of New York under Jurisdiction of the Department of Public Charities, 1909.) - Island Hospital, Roosevelt Island, New York County, NY

Dynamic Network Model for Smart City Data-Loss Resilience Case Study: City-to-City Network for Crime Analytics

PubMed Central

Kotevska, Olivera; Kusne, A. Gilad; Samarov, Daniel V.; Lbath, Ahmed; Battou, Abdella

2017-01-01

Today’s cities generate tremendous amounts of data, thanks to a boom in affordable smart devices and sensors. The resulting big data creates opportunities to develop diverse sets of context-aware services and systems, ensuring smart city services are optimized to the dynamic city environment. Critical resources in these smart cities will be more rapidly deployed to regions in need, and those regions predicted to have an imminent or prospective need. For example, crime data analytics may be used to optimize the distribution of police, medical, and emergency services. However, as smart city services become dependent on data, they also become susceptible to disruptions in data streams, such as data loss due to signal quality reduction or due to power loss during data collection. This paper presents a dynamic network model for improving service resilience to data loss. The network model identifies statistically significant shared temporal trends across multivariate spatiotemporal data streams and utilizes these trends to improve data prediction performance in the case of data loss. Dynamics also allow the system to respond to changes in the data streams such as the loss or addition of new information flows. The network model is demonstrated by city-based crime rates reported in Montgomery County, MD, USA. A resilient network is developed utilizing shared temporal trends between cities to provide improved crime rate prediction and robustness to data loss, compared with the use of single city-based auto-regression. A maximum improvement in performance of 7.8% for Silver Spring is found and an average improvement of 5.6% among cities with high crime rates. The model also correctly identifies all the optimal network connections, according to prediction error minimization. City-to-city distance is designated as a predictor of shared temporal trends in crime and weather is shown to be a strong predictor of crime in Montgomery County. PMID:29250476

Dynamic Network Model for Smart City Data-Loss Resilience Case Study: City-to-City Network for Crime Analytics.

PubMed

Kotevska, Olivera; Kusne, A Gilad; Samarov, Daniel V; Lbath, Ahmed; Battou, Abdella

2017-01-01

Today's cities generate tremendous amounts of data, thanks to a boom in affordable smart devices and sensors. The resulting big data creates opportunities to develop diverse sets of context-aware services and systems, ensuring smart city services are optimized to the dynamic city environment. Critical resources in these smart cities will be more rapidly deployed to regions in need, and those regions predicted to have an imminent or prospective need. For example, crime data analytics may be used to optimize the distribution of police, medical, and emergency services. However, as smart city services become dependent on data, they also become susceptible to disruptions in data streams, such as data loss due to signal quality reduction or due to power loss during data collection. This paper presents a dynamic network model for improving service resilience to data loss. The network model identifies statistically significant shared temporal trends across multivariate spatiotemporal data streams and utilizes these trends to improve data prediction performance in the case of data loss. Dynamics also allow the system to respond to changes in the data streams such as the loss or addition of new information flows. The network model is demonstrated by city-based crime rates reported in Montgomery County, MD, USA. A resilient network is developed utilizing shared temporal trends between cities to provide improved crime rate prediction and robustness to data loss, compared with the use of single city-based auto-regression. A maximum improvement in performance of 7.8% for Silver Spring is found and an average improvement of 5.6% among cities with high crime rates. The model also correctly identifies all the optimal network connections, according to prediction error minimization. City-to-city distance is designated as a predictor of shared temporal trends in crime and weather is shown to be a strong predictor of crime in Montgomery County.

Stay in Touch with City Hall - City of New York

Science.gov Websites

Signs and LocatorAbout NYC311NYC311 Mobile AppNYC311 TwitterNYC311 Facebook Directory of City Agencies Contact NYC Government City Employees Notify NYC CityStore Stay Connected NYC Mobile Apps Maps Resident

Distribution and detoxication of toxaphene in Clayton Lake, New Mexico

USGS Publications Warehouse

Kallman, Burton J.; Cope, Oliver B.; Navarre, Richard J.

1962-01-01

The fate of toxaphene, applied in three treatments at a total calculated concentration of 0.05 p.p.m. to Clayton Lake, New Mexico, was followed over a 1.5-year period. A detailed description of the chromatographic method of analysis is given. Water concentrations of toxaphene were higher in leeshore samples than in windward samples for 2 weeks after the application; toxaphene levels then appeared to reach a constant value of about 0.001 p.p.m. for at least an additional 250 days. Total body concentrations of toxaphene were determined in trout and bullheads present in the lake during the poisoning and in trout placed in the lake in live-cars subsequently. Trout were more susceptible to toxaphene and accumulated lower body levels than bullheads. Bullheads which showed symptoms of toxaphene poisoning when collected had higher levels than did normal-appearing individuals. No difference in levels was observed in live-car trout collected dead as compared to survivors. Aquatic vegetation accumulated high concentrations of toxaphene; low concentrations were found in some sediment samples. The significance of these findings is discussed.

Effect of Heat Index on Microstructure and Mechanical Behavior of Friction Stir Processed AZ31

NASA Astrophysics Data System (ADS)

Yuan, Wei; Mishra, Rajiv S.

Friction stir processing modifies the micro structure and properties of metals through intense plastic deformation. The frictional heat input affects the microstructure evolution and resulting mechanical properties. 2 mm thick commercial AZ31B-H24 Mg alloy was friction stir processed under various process parameter combinations to investigate the effect of heat index on micro structure and properties. Recrystallized grain structure in the nugget region was observed for all processing conditions with decrease in hardness. Results indicate a reduced tensile yield strength and ultimate tensile strength compared to the as-received material in H-temper, but with an improved hardening capacity. The strain hardening behavior of friction stir processed material is discussed.

Within city limits: nature and children's books about nature in the city

Treesearch

Leonard S. Marcus

1977-01-01

Many children's books give the impression that we must leave the city to be "in nature.'' This is a review of children's books about nature found within city limits. The books include a natural history of New York City; a guide to city wildflowers and other weeds; a book about city trees; a delightful inquiry into the true nature of the roach;...

Formation mechanisms of periodic longitudinal microstructure and texture patterns in friction stir welded magnesium AZ80

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hiscocks, J., E-mail: j.hiscocks@queensu.ca

Many studies of friction stir welding have shown that periodicity of metal flow around the tool pin may result in the formation of periodic differences in microstructure and texture in the weld nugget area correlated with the weld pitch. The current work investigates the periodicity of magnesium weld microtexture in the nugget region and its association with material flow using optical and electron microscopy. Two welds created in AZ80 at different processing conditions are presented in detail, one illustrating periodic longitudinal texture change, and one showing for the first time that periodic variations in texture, grain size, or composition aremore » not defining features of periodic nugget flow. While nugget texture is dominated by shear deformation, it was found here to be affected to a lesser degree by compaction of material behind the welding tool, which led to reduction in intensity of the shear texture fiber. The decreased tendency for magnesium based alloys to form periodic patterns as compared to aluminum based alloys is explained with reference to the shear textures. - Highlights: •It is shown here that periodic material flow in the nugget does not necessitate longitudinal texture patterns. •Longitudinal texture patterns are shown to be present or absent in Mg AZ80 based on processing conditions. •Texture in the nugget is mainly dictated by shear deformation, but has measurable effects from other deformation modes. •Explanation of why longitudinal texture change is frequently reported in aluminum but not magnesium alloys is provided. •A new vector visualization of material flow based on EBSD data analysis is shown.« less

Effect of Thermal History on Microstructures and Mechanical Properties of AZ31 Magnesium Alloy Prepared by Friction Stir Processing

PubMed Central

Chai, Fang; Zhang, Datong; Li, Yuanyuan

2014-01-01

Hot-rolled AZ31 (Mg-2.57Al-0.84Zn-0.32Mn, in mass percentage) magnesium alloy is subjected to friction stir processing in air (normal friction stir processing, NFSP) and under water (submerged friction stir processing, SFSP). Thermal history of the two FSP procedures is measured, and its effect on microstructures and mechanical properties of the experimental materials is investigated. Compared with NFSP, the peak temperature during SFSP is lower and the duration time at a high temperature is shorter due to the enhanced cooling effect of water. Consequently, SFSP results in further grain refinement, and the average grain size of the NFSP and SFSP specimens in the stir zone (SZ) are 2.9 μm and 1.3 μm, respectively. Transmission electron microscopy (TEM) examinations confirm that grain refinement is attributed to continuous dynamic recrystallization both for NFSP and SFSP. The average Vickers hardness in the SZ of the NFSP and SFSP AZ31 magnesium alloy are 76 HV and 87 HV. Furthermore, the ultimate tensile strength and the elongation of the SFSP specimen increase from 191 MPa and 31.3% in the NFSP specimen to 210 MPa and 50.5%, respectively. Both the NFSP and SFSP alloys fail through ductile fracture, but the dimples are much more obvious in the SFSP alloy. PMID:28788532

Arsenic Removal from Drinking Water by Adsorptive Media - U.S. EPA Demonstration Project at Covered Wells in Tohono O’odham Nation, AZ - Final Performance Evaluation Report

EPA Science Inventory

This report documents the activities performed and the results obtained from the arsenic removal treatment technology demonstration project at Covered Wells in Tohono O’odham Nation, AZ. The main objective of the project was to evaluate the effectiveness of AdEdge Technologies’ ...

Grain Refinement of AZ31 Magnesium Alloy Weldments by AC Pulsing Technique

NASA Astrophysics Data System (ADS)

Kishore Babu, N.; Cross, C. E.

2012-11-01

The current study has investigated the influence of alternating current pulsing on the structure and mechanical properties of AZ31 magnesium alloy gas tungsten arc (GTA) weldments. Autogenous full penetration bead-on-plate GTA welds were made under a variety of conditions including variable polarity (VP), variable polarity mixed (VPM), alternating current (AC), and alternating current pulsing (ACPC). AC pulsing resulted in significant refinement of weld metal when compared with the unpulsed conditions. AC pulsing leads to relatively finer and more equiaxed grain structure in GTA welds. In contrast, VP, VPM, and AC welding resulted in predominantly columnar grain structures. The reason for this grain refinement may be attributed to the periodic variations in temperature gradient and solidification rate associated with pulsing as well as weld pool oscillation observed in the ACPC welds. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness, tensile strength, and ductility.

Examples of grid generation with implicitly specified surfaces using GridPro (TM)/az3000. 1: Filleted multi-tube configurations

NASA Technical Reports Server (NTRS)

Cheng, Zheming; Eiseman, Peter R.

1995-01-01

With examples, we illustrate how implicitly specified surfaces can be used for grid generation with GridPro/az3000. The particular examples address two questions: (1) How do you model intersecting tubes with fillets? and (2) How do you generate grids inside the intersected tubes? The implication is much more general. With the results in a forthcoming paper which develops an easy-to-follow procedure for implicit surface modeling, we provide a powerful means for rapid prototyping in grid generation.

Contaminant-associated health effects in fishes from the Ottawa and Ashtabula Rivers, Ohio

USGS Publications Warehouse

Iwanowicz, Luke R.; Blazer, Vicki S.; Walsh, Heather L.; Shaw, Cassidy H.; DeVault, David S.; Banda, Jo A.

2018-01-01

The health of resident fishes serves as a biologically relevant barometer of aquatic ecosystem integrity. Here, the health of the Ottawa River and Ashtabula River (both within the Lake Erie Basin) were assessed using morphological and immunological biomarkers in brown bullheads (Ameiurus nebulosus) and largemouth bass (Micropterus salmoides). Biomarker metrics were compared to fish collected from a reference site (Conneaut Creek). Data utilized for analyses were collected between 2003 and 2011. Fish collected from all three river systems had markedly different contaminant profiles. Total PCBs were the dominant contaminant class by mass. In bullhead, PCBs were highest in fish from the Ashtabula River and there were no differences in fish collected pre- or post-remediation of Ashtabula Harbor (median = 4.6 and 5.5 mg/kg respectively). Excluding PCBs, the Ottawa River was dominated by organochlorine pesticides. Liver tumor prevalence exceeded the 5% trigger level at both the Ashtabula (7.7%) and Ottawa Rivers (10.2%), but was not statistically different than that at the reference site. There was no statistically significant association between microscopic lesions, gross pathology and contaminant body burdens. Collectively, contaminant body burdens were generally negatively correlated with functional immune responses including bactericidal, cytotoxic-cell and respiratory burst activity in both species. Exceptions were positive correlations of HCB and heptachlor epoxide with respiratory burst activity in largemouth bass, and HCB with respiratory burst activity in bullhead and ΣBHC for all three functional assays in bullhead. Data here provide additional support that organochlorine contamination is associated with immunomodulation, and that species differences exist within sites.

Women in Cities.

ERIC Educational Resources Information Center

Hurst, Liz

1982-01-01

Suggesting that women are at a disadvantage in cities and towns, discusses experiences of women at home, working women, women traveling, shopping, and growing old in cities. Includes suggestions for studying women in cities. (JN)

Monte Carlo simulation of collisionless shocks showing preferential acceleration of high A/Z particles. [in cosmic rays

NASA Technical Reports Server (NTRS)

Ellison, D. C.; Jones, F. C.; Eichler, D.

1981-01-01

A collisionless quasi-parallel shock is simulated by Monte Carlo techniques. The scattering of all velocity particles from thermal to high energy is assumed to occur so that the mean free path is directly proportional to velocity times the mass-to-charge-ratio, and inversely proporational to the plasma density. The shock profile and velocity spectra are obtained, showing preferential acceleration of high A/Z particles relative to protons. The inclusion of the back pressure of the scattering particles on the inflowing plasma produces a smoothing of the shock profile, which implies that the spectra are steeper than for a discontinuous shock.

A tale of two machines: a review of the BLAST meeting, Tucson, AZ, 20-24 January 2013.

PubMed

Josenhans, Christine; Jung, Kirsten; Rao, Christopher V; Wolfe, Alan J

2014-01-01

Since its inception, Bacterial Locomotion and Signal Transduction (BLAST) meetings have been the place to exchange and share the latest developments in the field of bacterial signal transduction and motility. At the 12th BLAST meeting, held last January in Tucson, AZ, researchers from all over the world met to report and discuss progress in diverse aspects of the field. The majority of these advances, however, came at the level of atomic level structures and their associated mechanisms. This was especially true of the biological machines that sense and respond to environmental changes. © 2013 John Wiley & Sons Ltd.

[Healthy Cities projects].

PubMed

Takano, Takehito

2002-05-01

This is a review article on "Healthy Cities". The Healthy Cities programme has been developed by the World Health Organization (WHO) to tackle urban health and environmental issues in a broad way. It is a kind of comprehensive policy package to carry out individual projects and activities effectively and efficiently. Its key aspects include healthy public policy, vision sharing, high political commitment, establishment of structural organization, strategic health planning, intersectoral collaboration, community participation, setting approach, development of supportive environment for health, formation of city health profile, national and international networking, participatory research, periodic monitoring and evaluation, and mechanisms for sustainability of projects. The present paper covered the Healthy Cities concept and approaches, rapid urbanization in the world, developments of WHO Healthy Cities, Healthy Cities developments in the Western Pacific Region, the health promotion viewpoint, and roles of research.

Jerusalem: City of Dreams, City of Sorrows

ERIC Educational Resources Information Center

Ricks, Thomas

2011-01-01

Jerusalem is more than an intriguing global historical city; it is a classroom for liberal learning and international understanding. It had never been a city of one language, one religion and one culture. Looking at the origins of Jerusalem's name indicates its international and multicultural nature. While Israelis designate Jerusalem as their…

Mechanical responses, texture evolution, and yield loci of extruded AZ31 magnesium alloy under various loading conditions: Experiment and modeling

NASA Astrophysics Data System (ADS)

Kabirian, Farhoud

Mechanical responses and texture evolution of extruded AZ31 Mg are measured under uniaxial (tension-compression) and multiaxial (free-end torsion) loadings. Compression loading is carried out in three different directions at temperature and strain rate ranges of 77-423 K and 10-4 -3000 s -1, respectively. Texture evolution at different intermediate strains reveals that crystal reorientation is exhausted at smaller strains with increase in strain rate while increase in temperature retards twinning. In addition to the well-known tension-compression yield asymmetry, a strong anisotropy in strain hardening response is observed. Strain hardening during the compression experiment is intensified with decreasing and increasing temperature and strain rate, respectively. This complex behavior is explained through understanding the roles of deformation mechanisms using the Visco-Plastic Self Consistent (VPSC) model. In order to calibrate the VPSC model's constants as accurate as possible, a vast number of mechanical responses including stress-strain curves in tension, compression in three directions, and free-end torsion, texture evolution at different strains, lateral strains of compression samples, twin volume fraction, and axial strain during the torsion experiment. Modeling results show that depending on the number of measurements used for calibration, roles of different mechanisms in plastic deformation change significantly. In addition, a precise definition of yield is established for the extruded AZ31magnesium alloy after it is subjected to different loading conditions (uniaxial to multiaxial) at four different plastic strains. The yield response is measured in ?-? space. Several yield criteria are studied to predict yield response of extruded AZ31. This study proposes an asymmetrical fourth-order polynomial yield function. Material constants in this model can be directly calculated using mechanical measurements. Convexity of the proposed model is discussed, and

77 FR 40798 - Safety Zone; Nautical City Festival Air Show, Rogers City MI

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-11

...-AA00 Safety Zone; Nautical City Festival Air Show, Rogers City MI AGENCY: Coast Guard, DHS. ACTION...; Nautical City Festival Air Show, Rogers City MI; in the Federal Register (77 FR 29932). We received no... Nautical City Festival will be celebrating Calcite's 100th Anniversary. As part of that celebration, an air...

Wide-field Imaging Survey of Dust Continuum Emissions at lambda = 1.1 mm toward the Chamaeleon and Lupus Regions with AzTEC on ASTE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Momose, Munetake; Hiramatsu, Masaaki; Tsukagoshi, Takashi

2009-08-05

We carried out an imaging survey of dust continuum emissions toward the Chamaeleon and Lupus regions. Observations were made with the 144-element bolometer array camera AzTEC mounted on the 10-meter sub-millimeter telescope ASTE during 2007-2008. The preliminary results of disk search and the cloud structure of Lupus III are presented.

Ultra-performance liquid chromatography tandem mass spectrometry method for the determination of AZ66, a sigma receptor ligand, in rat plasma and its application to in vivo pharmacokinetics.

PubMed

Jamalapuram, Seshulatha; Vuppala, Pradeep Kumar; Abdelazeem, Ahmed H; McCurdy, Christopher R; Avery, Bonnie A

2013-08-01

Methamphetamine abuse continues as a major problem in the USA owing to its powerful psychological addictive properties. AZ66, 3-[4-(4-cyclohexylpiperazine-1-yl)pentyl]-6-fluorobenzo[d]thiazole-2(3H)-one, an optimized sigma receptor ligand, is a promising therapeutic agent against methamphetamine. To study the in vivo pharmacokinetics of this novel sigma receptor ligand in rats, a sensitive ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) method was developed in rat plasma and validated. The developed method requires a small volume of plasma (100 μL) and a simple liquid-liquid extraction. The chromatographic separations were achieved in 3.3 min using an Acquity UPLC BEH Shield RP18 column. The mass spectrophotometric detection was carried out using a Waters Micromass Quattro MicroTM triple-quadrupole system. Multiple reaction monitoring was used for the quantitation with transitions m/z 406 → m/z 181 for AZ66 and m/z 448 → m/z 285 for aripiprazole. The method was validated over a concentration range of 1-3500 ng/mL and the lower limit of quantitation was determined to be 1 ng/mL. Validation of the assay demonstrated that the developed UPLC/MS/MS method was sensitive, accurate and selective for the determination of AZ66 in rat plasma. The present method has been successfully applied to an i.v. pharmacokinetic study in Sprague-Dawley rats. Copyright © 2013 John Wiley & Sons, Ltd.

33 CFR 100.919 - International Bay City River Roar, Bay City, MI.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false International Bay City River Roar, Bay City, MI. 100.919 Section 100.919 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Bay City River Roar, Bay City, MI. (a) Regulated Area. A regulated area is established to include all...

33 CFR 100.919 - International Bay City River Roar, Bay City, MI.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false International Bay City River Roar, Bay City, MI. 100.919 Section 100.919 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF... Bay City River Roar, Bay City, MI. (a) Regulated Area. A regulated area is established to include all...

44. Photocopy of photograph, photographer unknown, 1415 June 1929 (original ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. Photocopy of photograph, photographer unknown, 14-15 June 1929 (original print located at Utah State Historical Society Photograph Collection, Salt Lake City UT). DEDICATION CEREMONY AT BRIDGE. - Navajo Bridge, Spanning Colorado River at U.S. Highway 89 Alternate, Page, Coconino County, AZ

Microstructure stability of ultra-fine grained magnesium alloy AZ31 processed by extrusion and equal-channel angular pressing (EX–ECAP)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stráská, Jitka, E-mail: straska.jitka@gmail.com; Janeček, Miloš, E-mail: janecek@met.mff.cuni.cz; Čížek, Jakub, E-mail: jcizek@mbox.troja.mff.cuni.cz

Thermal stability of the ultra-fine grained (UFG) microstructure of magnesium AZ31 alloy was investigated. UFG microstructure was achieved by a combined two-step severe plastic deformation process: the extrusion (EX) and subsequent equal-channel angular pressing (ECAP). This combined process leads to refined microstructure and enhanced microhardness. Specimens with UFG microstructure were annealed isochronally at temperatures 150–500 °C for 1 h. The evolution of microstructure, mechanical properties and dislocation density was studied by electron backscatter diffraction (EBSD), microhardness measurements and positron annihilation spectroscopy (PAS). The coarsening of the fine-grained structure at higher temperatures was accompanied by a gradual decrease of the microhardnessmore » and decrease of dislocation density. Mechanism of grain growth was studied by general equation for grain growth and Arrhenius equation. Activation energies for grain growth were calculated to be 115, 33 and 164 kJ/mol in temperature ranges of 170–210 °C, 210–400 °C and 400–500 °C (443–483 K, 483–673 K and 673–773 K), respectively. - Highlights: • Microhardness of UFG AZ31 alloy decreases with increasing annealing temperature. • This fact has two reasons: dislocation annihilations and/or grain growth. • The activation energies for grain growth were calculated for all temperature ranges.« less

Structure and properties of a duplex coating combining micro-arc oxidation and baking layer on AZ91D Mg alloy

NASA Astrophysics Data System (ADS)

Cui, Xue-Jun; Li, Ming-Tian; Yang, Rui-Song; Yu, Zu-Xiao

2016-02-01

A duplex coating (called MAOB coating) was fabricated on AZ91D Mg alloy by combining the process of micro-arc oxidation (MAO) with baking coating (B-coating). The structure, composition, corrosion resistance, and tribological behaviour of the coatings were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), electrochemical and long-term immersion test, and ball-on-disc friction test. The results show that a dense 92 μm thick B-coating was tightly deposited onto the MAO-coated Mg alloy and exhibited a good mechanical interlock along the rough interface. Compared with the MAO-coated sample, the corrosion current density of the MAOB-coated Mg alloy decreased by two or three orders of magnitude and no corrosion phenomenon was observed during a long-term immersion test of about 500 h (severe corrosion pits were found for MAO-treated samples after about 168 h of immersion). The frictional coefficient values of the MAOB coating were similar to those of the MAO coating using dry sliding tests, while the B-coating on the MAO-coated surface significantly improved the wear resistance of the AZ91D Mg alloy. All of these results indicate that a B-coating can be used to further protect Mg alloys from corrosion and wear by providing a thick, dense barrier.

Morphotectonic evolution of Maviboğaz canyon and Suğla polje, SW central Anatolia, Turkey

NASA Astrophysics Data System (ADS)

Doğan, Uğur; Koçyiğit, Ali

2018-04-01

This study focuses on the morphotectonic evolutionary history of two significant geomorphic features, Suğla structural-border polje and Maviboğaz canyon, located within the Suğla-Seydişehir, Akören-Kavakköy, and Bozkır grabens in the central Taurides. Data were obtained by detailed field mapping of faults, rocks, and geomorphic features. Three phases of tectonic deformation were determined. The three erosional surfaces developed, especially in the form of tectonically controlled steps, during Oligocene-early Miocene, middle Miocene, and late Miocene-early Pliocene, sequentially. Southwest- to northeast-trending karstified hanging paleovalleys are present on the high erosional surfaces, which have been attributed to the end of early Miocene and late Miocene. Faulting-induced tectonic movements enabled the formation of Suğla-Seydişehir paleograben in early Miocene. We suggest that the Maviboğaz canyon was formed by captures at the beginning of late Miocene and late Pliocene and by incision in Late Pliocene-Quaternary, depending on the headward erosion of Çarşamba River. Starting from the beginning of Quaternary, a tensional neotectonic regime became prominent and then a series of modern graben-horst structures formed along the reactivated older grabens. One of these is the Suğla-Seydişehir reactivated graben. Suğla structural-border polje developed within the graben. Total visible tectonic subsidence of the polje is 134 m. Underground capture of surface water occurred on the southern slopes of the graben. Waters of Suğla polje are transported intermittently into Konya basin on the surface and into the Mediterranean basin via natural swallow holes. Beach deposits, water marks, cliffs, and notches marking the late Pleistocene lake level (10 m) and two perched corrosion surfaces ( 50 and 22 m) were detected around the polje.

The SMC B-type supergiant AzV322: a g-mode pulsator with a circumstellar disc

NASA Astrophysics Data System (ADS)

Mennickent, R. E.; Kołaczkowski, Z.; Soszyński, I.; Cabezas, M.; Garrido, H. E.

2018-01-01

We present a photometric and spectroscopic study of AzV322, an emission line object located in the Small Magellanic Cloud previously classified between O9 and B0. We analyse 17.5 yr of I- and V-band OGLE-II, -III and -IV light curves and find four significant frequencies, viz. f1 = 0.386 549 ± 0.000 003, f2 = 0.101 177 ± 0.000 005, f3 = 0.487 726 ± 0.000 015 and f4 = 0.874 302 ± 0.000 020 cycles d-1 . The f1 frequency (period 2.587 00 ± 0.000 02 d) provides the stronger periodogram peak and gives a single wave light curve of full amplitude 0.066 mag in the I band. High-resolution optical spectroscopy confirms the early B-type spectral type and reveals prominent double peak Balmer, Paschen, O I 8446 and He I 5875 emissions. The spectral energy distribution shows significant colour excess towards long wavelengths possibly attributed to free-free emission in a disc -like envelope. Our analysis yields Teff = 23 000 ± 1500 K, log g = 3.0 ± 0.5, M = 16 ± 1 M⊙, R = 31.0 ± 1.1 R⊙ and Lbol = 104.87 ± 0.06 L⊙. AzV322 might be a member of the new class of slowly pulsating B supergiants introduced by Saio et al. and documented by Lefever, Puls & Aerts; however its circumstellar disc makes it an hither to unique object. Furthermore, we notice that an O-C analysis for f1 reveals quasi-cyclic changes for the times of maximum in a time-scale of 20 yr, which might indicate a light-travel time effect in a very wide orbit binary with an undetected stellar component.

City 2020+

NASA Astrophysics Data System (ADS)

Schneider, C.; Buttstädt, M.; Merbitz, H.; Sachsen, T.; Ketzler, G.; Michael, S.; Klemme, M.; Dott, W.; Selle, K.; Hofmeister, H.

2010-09-01

This research initiative CITY 2020+ assesses the risks and opportunities for residents in urban built environments under projected demographic and climate change for the year 2020 and beyond, using the City of Aachen as a case study. CITY 2020+ develops scenarios, options and tools for planning and developing sustainable future city structures. We investigate how urban environment, political structure and residential behavior can best be adapted, with attention to the interactions among structural, political, and sociological configurations and with their consequences on human health. Demographers project that in the EU-25-States by 2050, approximately 30% of the population will be over age 65. Also by 2050, average tem¬peratures are projected to rise by 1 to 2 K. Combined, Europe can expect enhanced thermal stress and higher levels of particulate matter. CITY 2020+ amongst other sub-projects includes research project dealing with (1) a micro-scale assessment of blockages to low-level cold-air drainage flow into the city centre by vegetation and building structures, (2) a detailed analysis of the change of probability density functions related to the occurrence of heat waves during summer and the spatial and temporal structure of the urban heat island (UHI) (3) a meso-scale analysis of particulate matter (PM) concentrations depending on topography, local meteorological conditions and synoptic-scale weather patterns. First results will be presented specifically from sub-projects related to vegetation barriers within cold air drainage, the assessment of the UHI and the temporal and spatial pattern of PM loadings in the city centre. The analysis of the cold air drainage flow is investigated in two consecutive years with a clearing of vegetation stands in the beginning of the second year early in 2010. The spatial pattern of the UHI and its possible enhancement by climate change is addressed employing a unique setup using GPS devices and temperature probes fixed to

Sequence of Reston Virus Isolate AZ-1435, an Ebolavirus Isolate Obtained during the 1989-1990 Reston Virus Epizootic in the United States.

PubMed

Cornish, Joseph P; Diaz, Larissa; Ricklefs, Stacy M; Kanakabandi, Kishore; Sword, Jennifer; Jahrling, Peter B; Kuhn, Jens H; Porcella, Stephen F; Johnson, Reed F

2017-01-12

Reston virus (RESTV) was discovered in 1989-1990 during three connected epizootics of highly lethal viral hemorrhagic fever among captive macaques in primate housing facilities in the United States and Philippines. Currently, only one RESTV isolate from that outbreak (named Pennsylvania) has been sequenced. Here, we report the sequence of a second isolate, Reston virus/M.fascicularis-tc/USA/1990/Philippines89-AZ1435. Copyright © 2017 Cornish et al.

On the Internet of Things, smart cities and the WHO Healthy Cities

PubMed Central

2014-01-01

This article gives a brief overview of the Internet of Things (IoT) for cities, offering examples of IoT-powered 21st century smart cities, including the experience of the Spanish city of Barcelona in implementing its own IoT-driven services to improve the quality of life of its people through measures that promote an eco-friendly, sustainable environment. The potential benefits as well as the challenges associated with IoT for cities are discussed. Much of the 'big data' that are continuously generated by IoT sensors, devices, systems and services are geo-tagged or geo-located. The importance of having robust, intelligent geospatial analytics systems in place to process and make sense of such data in real time cannot therefore be overestimated. The authors argue that IoT-powered smart cities stand better chances of becoming healthier cities. The World Health Organization (WHO) Healthy Cities Network and associated national networks have hundreds of member cities around the world that could benefit from, and harness the power of, IoT to improve the health and well-being of their local populations. PMID:24669838

On the Internet of Things, smart cities and the WHO Healthy Cities.

PubMed

Kamel Boulos, Maged N; Al-Shorbaji, Najeeb M

2014-03-27

This article gives a brief overview of the Internet of Things (IoT) for cities, offering examples of IoT-powered 21st century smart cities, including the experience of the Spanish city of Barcelona in implementing its own IoT-driven services to improve the quality of life of its people through measures that promote an eco-friendly, sustainable environment. The potential benefits as well as the challenges associated with IoT for cities are discussed. Much of the 'big data' that are continuously generated by IoT sensors, devices, systems and services are geo-tagged or geo-located. The importance of having robust, intelligent geospatial analytics systems in place to process and make sense of such data in real time cannot therefore be overestimated. The authors argue that IoT-powered smart cities stand better chances of becoming healthier cities. The World Health Organization (WHO) Healthy Cities Network and associated national networks have hundreds of member cities around the world that could benefit from, and harness the power of, IoT to improve the health and well-being of their local populations.

Services Oriented Smart City Platform Based On 3d City Model Visualization

NASA Astrophysics Data System (ADS)

Prandi, F.; Soave, M.; Devigili, F.; Andreolli, M.; De Amicis, R.

2014-04-01

The rapid technological evolution, which is characterizing all the disciplines involved within the wide concept of smart cities, is becoming a key factor to trigger true user-driven innovation. However to fully develop the Smart City concept to a wide geographical target, it is required an infrastructure that allows the integration of heterogeneous geographical information and sensor networks into a common technological ground. In this context 3D city models will play an increasingly important role in our daily lives and become an essential part of the modern city information infrastructure (Spatial Data Infrastructure). The work presented in this paper describes an innovative Services Oriented Architecture software platform aimed at providing smartcities services on top of 3D urban models. 3D city models are the basis of many applications and can became the platform for integrating city information within the Smart-Cites context. In particular the paper will investigate how the efficient visualisation of 3D city models using different levels of detail (LODs) is one of the pivotal technological challenge to support Smart-Cities applications. The goal is to provide to the final user realistic and abstract 3D representations of the urban environment and the possibility to interact with a massive amounts of semantic information contained into the geospatial 3D city model. The proposed solution, using OCG standards and a custom service to provide 3D city models, lets the users to consume the services and interact with the 3D model via Web in a more effective way.

A comparison of deformation and failure behaviors of AZ31 and E-form Mg alloys under V-bending test

NASA Astrophysics Data System (ADS)

Choi, Shi-Hoon; Singh, Jaiveer; Kim, Min-Seong; Yoon, Jeong-Whan

2016-08-01

Deformation and failure behaviors of magnesium (Mg) alloys (AZ31 and E-form) were investigated using V-bending test. Formability of these Mg alloys was discussed in terms of minimum bending radius. Microtexture evolution in the deformed Mg alloys was examined via electron back-scattered diffraction (EBSD) technique. Two level simulation technique which combined continuum finite element method (FEM) and crystal plasticity FEM successfully simulated the microtexture evolution in Mg alloys during V-bending test. The effect of deformation twinning on the failure in Mg alloys was also examined.

Analysis of the Small Business Administration 8(a) Business Development Program

DTIC Science & Technology

2015-06-01

Parent DUNS Number: Address, line 1: 9656 E Empress Ave Address, line 2: City: Mesa State: AZ Zip: 85208-3156 Phone Number: 480-220-9226 Fax...products): https://www.imgnetworks.com Contact Person: RAY RODRIGUEZ County Code (3 digit): 073 Congressional District: 51 Metropolitan

Protein-Protein Förster Resonance Energy Transfer Analysis of Nucleosome Core Particles Containing H2A and H2A.Z

PubMed Central

Hoch, Duane A.; Stratton, Jessica J.; Gloss, Lisa M.

2007-01-01

A protein-protein Förster resonance energy transfer (FRET) system, employing probes at multiple positions, was designed to specifically monitor the dissociation of the H2A-H2B dimer from the nucleosome core particle (NCP). Tryptophan donors and Cys-AEDANS acceptors were chosen because, in comparison to fluorophores used in previous NCP FRET studies, they: 1) are smaller and less hydrophobic which should minimize perturbations of histone and NCP structure; and 2) have an R0 of 20 Å, which is much less than the dimensions of the NCP (~50 Å width and ~100 Å diameter). CD and FL equilibrium protein unfolding titrations indicate that the donor and acceptor moieties have minimal effects on the stability of the H2A-H2B dimer and (H3-H4)2 tetramer. NCPs containing the various FRET pairs were reconstituted with the 601 artificial positioning DNA sequence. Equilibrium NaCl-induced dissociation of the modified NCPs showed that the 601 sequence stabilized the NCP to dimer dissociation as compared to previous studies using weaker positioning sequences. This finding implies a significant role for the H2A-H2B dimers in determining the DNA sequence dependence of NCP stability. The free energy of dissociation determined from reversible and well-defined sigmoidal transitions revealed two distinct phases reflecting the dissociation of each H2A-H2B dimer, confirming cooperativity in dimer dissociation. While cooperativity in the association/dissociation of the H2A-H2B dimers has been suggested previously, these data allow its quantitative description. The protein-protein FRET system was then used to study the effects of the histone variant H2A.Z on NCP stability; previous studies have reported both destabilizing and stabilizing effects. Comparison of the H2A and H2A.Z FRET NCP dissociation transitions suggest a slight increase in stability but a significant increase in cooperativity for dimer dissociation from H2A.Z NCPs. Thus, the utility of this protein-protein FRET system to

77 FR 39413 - Safety Zone: Crescent City Fourth of July Fireworks Event, Crescent City, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-03

...-AA00 Safety Zone: Crescent City Fourth of July Fireworks Event, Crescent City, CA AGENCY: Coast Guard... the navigable waters near Crescent City Harbor in Crescent City, CA in support of the Crescent City... establish safety zones (33 U.S.C sections 1221 et seq.). Crescent City-Del Norte County Chamber of Commerce...

75 FR 56467 - Safety Zone; Ocean City Beachfront Air Show, Ocean City, NJ

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

...-AA00 Safety Zone; Ocean City Beachfront Air Show, Ocean City, NJ AGENCY: Coast Guard, DHS. ACTION... Atlantic Ocean, Ocean City, NJ. The temporary safety zone will restrict vessel traffic from a portion of the Atlantic Ocean during the Ocean City Beachfront Air Show, which is an aerial demonstration to be...

76 FR 31235 - Safety Zone; Ocean City Air Show, Atlantic Ocean, Ocean City, MD

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-31

...-AA00 Safety Zone; Ocean City Air Show, Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS. ACTION... in the vicinity of Ocean City, MD to support the Ocean City Air Show. This action is necessary to provide for the safety of life on navigable waters during the Ocean City Air Show. This action is intended...

Ecological comparisons of Lake Erie tributaries with elevated incidence of fish tumors

USGS Publications Warehouse

Smith, Stephen B.; Blouin, Marc A.; Mac, Michael J.

1994-01-01

Ecological comparisons were made between two Lake Erie tributaries (Black and Cuyahoga rivers) with contaminated sediments and elevated rates of tumors in fish populations and a third, relatively unpolluted, reference tributary, the Huron River. Fish populations, benthic invertebrates, and sediments were evaluated in all three Ohio rivers. Community structure analyses indicated similar total densities but lower species diversity for fish and benthic invertebrates in the contaminated rivers when compared with the reference river. Growth rates in fish from the contaminated areas were either similar to or higher than those offish from the reference site. Brown bullhead (Ameiurus nebulosus) from the two contaminated tributaries exhibited 51% (Black River) and 45% (Cuyahoga River) incidence of liver lesions (neoplastic and preneoplastic) as compared with a 4% incidence of liver lesions in brown bullhead from the reference river (Huron River). Incidence of external abnormalities on brown bullhead was 54% (Black River) and 73% (Cuyahoga River) as compared with a 14% incidence on fish from the Huron River. On a regional basis, incidence of external abnormalities on particular benthic fish species may be an effective method to quickly indicate areas for more intensive contaminant studies.

A MASSIVE MOLECULAR GAS RESERVOIR IN THE z = 5.3 SUBMILLIMETER GALAXY AzTEC-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riechers, Dominik A.; Scoville, Nicholas Z.; Capak, Peter L.

2010-09-10

We report the detection of CO J = 2{yields}1, 5{yields}4, and 6{yields}5 emission in the highest-redshift submillimeter galaxy (SMG) AzTEC-3 at z = 5.298, using the Expanded Very Large Array and the Plateau de Bure Interferometer. These observations ultimately confirm the redshift, making AzTEC-3 the most submillimeter-luminous galaxy in a massive z {approx_equal} 5.3 protocluster structure in the COSMOS field. The strength of the CO line emission reveals a large molecular gas reservoir with a mass of 5.3 x 10{sup 10}({alpha}{sub CO}/0.8) M {sub sun}, which can maintain the intense 1800 M {sub sun} yr{sup -1} starburst in this systemmore » for at least 30 Myr, increasing the stellar mass by up to a factor of six in the process. This gas mass is comparable to 'typical' z {approx} 2 SMGs and constitutes {approx_gt}80% of the baryonic mass (gas+stars) and 30%-80% of the total (dynamical) mass in this galaxy. The molecular gas reservoir has a radius of <4 kpc and likely consists of a 'diffuse', low-excitation component, containing (at least) 1/3 of the gas mass (depending on the relative conversion factor {alpha}{sub CO}), and a 'dense', high-excitation component, containing {approx}2/3 of the mass. The likely presence of a substantial diffuse component besides highly excited gas suggests different properties between the star-forming environments in z > 4 SMGs and z > 4 quasar host galaxies, which perhaps trace different evolutionary stages. The discovery of a massive, metal-enriched gas reservoir in an SMG at the heart of a large z = 5.3 protocluster considerably enhances our understanding of early massive galaxy formation, pushing back to a cosmic epoch where the universe was less than 1/12 of its present age.« less

Archaeological studies at Drill Hole U20az Pahute Mesa, Nye county, Nevada. [Contains bibliography

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, A.H.; Hemphill, M.L.; Henton, G.H.

1991-07-01

During the summer of 1987, the Quaternary Sciences Center (formerly Social Science Center) of the Desert Research Institute (DRI), University of Nevada System, conducted data recovery investigations at five archaeological sites located near Drill Hole U20az on the Nevada Test Site in southern Nevada. These sites were among 12 recorded earlier during an archaeological survey of the drill hole conducted as part of the environmental compliance activities of the Department of Energy (DOE). The five sites discussed in this report were considered eligible for the National Register of Historic Places and were in danger of being adversely impacted by constructionmore » activities or by effects of the proposed underground nuclear test. Avoidance of these sites was not a feasible alternative; thus DRI undertook a data recovery program to mitigate expected adverse impacts. DRI's research plan included controlled surface collections and excavation of the five sites in question, and had the concurrence of the Nevada Division of Historic Preservation and Archaeology and the Advisory Council of Historic Preservation. Of the five sites investigated, the largest and most complex, 26Ny5207, consists of at least three discrete artifact concentrations. Sites 26Ny5211 and 26Ny5215, both yielded considerable assemblages. Site 26Ny5206 is very small and probably is linked to 26Ny5207. Site 26Ny5205 contained a limited artifact assemblage. All of the sites were open-air occurrences, and, with one exception contained no or limited subsurface cultural deposits. Only two radiocarbon dates were obtained, both from 26Ny5207 and both relatively recent. While the investigations reported in the volume mitigate most of the adverse impacts from DOE activities at Drill Hole U20az, significant archaeological sites may still exist in the general vicinity. Should the DOE conduct further activities in the region, additional cultural resource investigations may be required. 132 refs., 71 figs., 44 tabs.« less

Comparison of Electrochemical Methods for the Evaluation of Cast AZ91 Magnesium Alloy

PubMed Central

Tkacz, Jakub; Minda, Jozef; Fintová, Stanislava; Wasserbauer, Jaromír

2016-01-01

Linear polarization is a potentiodynamic method used for electrochemical characterization of materials. Obtained values of corrosion potential and corrosion current density offer information about material behavior in corrosion environments from the thermodynamic and kinetic points of view, respectively. The present study offers a comparison of applications of the linear polarization method (from −100 mV to +200 mV vs. EOCP), the cathodic polarization of the specimen (−100 mV vs. EOCP), and the anodic polarization of the specimen (+100 mV vs. EOCP), and a discussion of the differences in the obtained values of the electrochemical characteristics of cast AZ91 magnesium alloy. The corrosion current density obtained by cathodic polarization was similar to the corrosion current density obtained by linear polarization, while a lower value was obtained by anodic polarization. Signs of corrosion attack were observed only in the case of linear polarization including cathodic and anodic polarization of the specimen. PMID:28774046

Modelling of peak temperature during friction stir processing of magnesium alloy AZ91

NASA Astrophysics Data System (ADS)

Vaira Vignesh, R.; Padmanaban, R.

2018-02-01

Friction stir processing (FSP) is a solid state processing technique with potential to modify the properties of the material through microstructural modification. The study of heat transfer in FSP aids in the identification of defects like flash, inadequate heat input, poor material flow and mixing etc. In this paper, transient temperature distribution during FSP of magnesium alloy AZ91 was simulated using finite element modelling. The numerical model results were validated using the experimental results from the published literature. The model was used to predict the peak temperature obtained during FSP for various process parameter combinations. The simulated peak temperature results were used to develop a statistical model. The effect of process parameters namely tool rotation speed, tool traverse speed and shoulder diameter of the tool on the peak temperature was investigated using the developed statistical model. It was found that peak temperature was directly proportional to tool rotation speed and shoulder diameter and inversely proportional to tool traverse speed.

Becoming a Lifelong Learning City: Lessons from a Provincial City in South Korea

ERIC Educational Resources Information Center

Kwon, In Tak; Kim, Junghwan; Lim, Doo Hun

2015-01-01

This paper is designed to explore Jeonju City's strategies to build a successful lifelong learning city by analyzing the practices for the Lifelong Learning City Movement (LLCM) and then draw the limitations and needed tasks for building a Lifelong Learning City at the local government level. As Cunningham (1993) pointed out, we found some gaps…

77 FR 29932 - Safety Zone; Nautical City Festival Air Show, Rogers City, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-21

...-AA00 Safety Zone; Nautical City Festival Air Show, Rogers City, MI AGENCY: Coast Guard, DHS. ACTION... City Festival will be celebrating Calcite's 100th Anniversary. As part of that celebration, an air show will be launched to the east of the Rogers City marina. The Captain of the Port Sault Sainte Marie has...

Preparation of Composite Coating on AZ91D Magnesium Alloy by Silica Sol-Micro Oxidation

NASA Astrophysics Data System (ADS)

Shao, Zhongcai; Zhang, Feifei; Zhao, Ruiqiang; Shen, Xiaoyi

2016-03-01

Composite coating was prepared on AZ91D magnesium alloy with a new method which combined silica sol with micro-arc oxidation (MAO). The MAO coating was prepared on the basis of MAO solution, and then coated by sol-gel process. The composite coating was obtained after second MAO treatment. Scanning electron microscopy coupled with X-ray diffraction (XRD), energy spectrum analysis and electrochemical testing was applied to characterize the properties of MAO coating and composite coating. The experimental test results indicated that the Si element derived from SiO2 gel particle embedded into the MAO coating by second MAO treatment. The surface of composite coating became dense and the holes were smaller with silica sol sealing process. The corrosion resistance of composite coating was improved than the MAO coating.

Formation Mechanism of Discoloration on Die-Cast AZ91D Components Surface After Chemical Conversion

NASA Astrophysics Data System (ADS)

Liu, Bao-sheng; Wei, Ying-hui; Hou, Li-feng

2013-01-01

A notebook (NB) computer component was manufactured from AZ91D Mg alloy by a die-casting process. After chemical conversion treatment, a discoloration was noted on the component surface. The source of this discoloration has been studied in detail by scanning electron microscopy, energy dispersive spectroscopy, and spark atomic absorption spectroscopy. The corrosion resistance was also measured by potentiodynamic polarization, hydrogen evolution and salt spray testing. The formation mechanism for the discoloration which was caused by the residue left behind by excess mold release agent sprayed during the die-casting was discussed in detail. After chemical conversion treatment, the residual-baked mold release agent was apparent on the component surface as "white ash." Consequently, it degraded seriously both the appearance and the corrosion resistance of the manufactured component.

Sinking Coastal Cities

NASA Astrophysics Data System (ADS)

Erkens, G.; Stuurman, R.; De Lange, G.; Bucx, T.; Lambert, J.

2014-12-01

In many coastal cities land subsidence now exceeds absolute sea level rise up to a factor of ten. Without action, parts of Jakarta, Ho Chi Minh City, Bangkok and numerous other coastal cities will continue to sink, even below sea level. The ever increasing industrial and domestic demand for water in these cities results in excessive groundwater extraction, causing severe subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick sequences of soft soil. The impacts of subsidence are further exacerbated by climate-induced sea level rise. Land subsidence results in two types damage: foremost it increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. Secondly, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs of roads and transportation networks, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually. To survey the extent of groundwater associated subsidence, we conducted a quick-assessment of subsidence in a series of mega-cities (Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok). For each city research questions included: what are the main causes, how much is the current subsidence rate and what are predictions, where are the vulnerable areas, what are the impacts and risks, how can adverse impacts can be mitigated or compensated for, and what governmental bodies are involved and responsible to act? Using the assessment, this paper discusses subsidence modelling and measurement results from the selected cities. The focus is on the importance of delayed settlement after increases in hydraulic heads, the role of the subsurface composition for subsidence rates and best practice solutions for subsiding cities. For the latter, urban (ground)water management, adaptive flood risk management

Study of City Landscape Heritage Using Lidar Data and 3d-City Models

NASA Astrophysics Data System (ADS)

Rubinowicz, P.; Czynska, K.

2015-04-01

In contemporary town planning protection of urban landscape is a significant issue. It regards especially those cities, where urban structures are the result of ages of evolution and layering of historical development process. Specific panoramas and other strategic views with historic city dominants can be an important part of the cultural heritage and genius loci. Other hand, protection of such expositions introduces limitations for future based city development. Digital Earth observation techniques creates new possibilities for more accurate urban studies, monitoring of urbanization processes and measuring of city landscape parameters. The paper examines possibilities of application of Lidar data and digital 3D-city models for: a) evaluation of strategic city views, b) mapping landscape absorption limits, and c) determination protection zones, where the urbanization and buildings height should be limited. In reference to this goal, the paper introduces a method of computational analysis of the city landscape called Visual Protection Surface (VPS). The method allows to emulate a virtual surface above the city including protection of a selected strategic views. The surface defines maximum height of buildings in such a way, that no new facility can be seen in any of selected views. The research includes also analyses of the quality of simulations according the form and precision of the input data: airborne Lidar / DSM model and more advanced 3D-city models (incl. semantic of the geometry, like in CityGML format). The outcome can be a support for professional planning of tall building development. Application of VPS method have been prepared by a computer program developed by the authors (C++). Simulations were carried out on an example of the city of Dresden.

77 FR 55787 - Proposed Flood Elevation Determinations for the City of Carson City, NV

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-11

...-2011-0002; Internal Agency Docket No. FEMA-B-1233] Proposed Flood Elevation Determinations for the City of Carson City, NV AGENCY: Federal Emergency Management Agency, DHS. ACTION: Proposed rule... concerning proposed flood elevation determinations for the City of Carson City, Nevada. DATES: This...

Effects of inorganic nitrogen sources on the production of PP-V [(10Z)-12-carboxyl-monascorubramine] and the Expression of the nitrate assimilation gene cluster by Penicillium sp. AZ.

PubMed

Arai, Teppei; Umemura, Sara; Ota, Tamaki; Ogihara, Jun; Kato, Jun; Kasumi, Takafumi

2012-01-01

A fungal strain, Penicillium sp. AZ, produced the azaphilone Monascus pigment homolog when cultured in a medium composed of soluble starch, ammonium nitrate, yeast extract, and citrate buffer, pH 5.0. One of the typical features of violet pigment PP-V [(10Z)-12-carboxyl-monascorubramine] is that pyranoid oxygen is replaced with nitrogen. In this study, we found that ammonia and nitrate nitrogen are available for PP-V biosynthesis, and that ammonia nitrogen was much more effective than nitrate nitrogen. Further, we isolated nitrate assimilation gene cluster, niaD, niiA, and crnA, and analyzed the expression of these genes. The expression levels of all these genes increased with sodium nitrate addition to the culture medium. The results obtained here strongly suggest that Penicillium sp. AZ produced PP-V using nitrate in the form of ammonium reduced from nitrate through a bioprocess assimilatory reaction.

Green city Banda Aceh: city planning approach and environmental aspects

NASA Astrophysics Data System (ADS)

Arif, A. A.

2017-02-01

Banda Aceh as the capital of Aceh Province is the region with the tsunami disaster that occurred on December 26, 2004 the most severe of which over 60% of the city area were destroyed mainly coastal region and settlements. One product plan for rehabilitation and reconstruction of Banda Aceh is made of Banda Aceh as Green City. To realize the Green City Banda Aceh, urban development process should be conducted in a planned and integrated way with attention to spatial and environmental aspects to ensure an efficient urban management and to create a healthy, beautiful and comfortable environment. There is a weakness of the process in urban planning and development that occurred at present where cities tend to minimize the development of green open space and land conversion into a commercial district, residential areas, industrial areas, transport networks and infrastructure and facilities for other cities. Another tendency that occurs is urban environment only developed economically but not ecologically, whereas ecological balance is as important as the development of the economic value of urban areas. Such conditions have caused unbalance of urban ecosystems including increased air temperature, air pollution, declining water table, flooding, salt water intrusion and increased content of heavy metals in the soil. From an ecological perspective, unfavorable microclimate, high-temperature increase due to the lack of trees as a sieve / filter against heavy rain, can cause flooding. These conditions result in inconvienient, arid and less beautiful urban areas. The author identifies the elements contained in the Green City Banda Aceh and how the efforts and approaches must be made toward Green City Banda Aceh.

The AzTEC millimeter-wave camera: Design, integration, performance, and the characterization of the (sub-)millimeter galaxy population

NASA Astrophysics Data System (ADS)

Austermann, Jason Edward

One of the primary drivers in the development of large format millimeter detector arrays is the study of sub-millimeter galaxies (SMGs) - a population of very luminous high-redshift dust-obscured starbursts that are widely believed to be the dominant contributor to the Far-Infrared Background (FIB). The characterization of such a population requires the ability to map large patches of the (sub-)millimeter sky to high sensitivity within a feasible amount of time. I present this dissertation on the design, integration, and characterization of the 144-pixel AzTEC millimeter-wave camera and its application to the study of the sub-millimeter galaxy population. In particular, I present an unprecedented characterization of the "blank-field" (fields with no known mass bias) SMG number counts by mapping over 0.5 deg^2 to 1.1mm depths of ~1mJy - a previously unattained depth on these scales. This survey provides the tightest SMG number counts available, particularly for the brightest and rarest SMGs that require large survey areas for a significant number of detections. These counts are compared to the predictions of various models of the evolving mm/sub-mm source population, providing important constraints for the ongoing refinement of semi-analytic and hydrodynamical models of galaxy formation. I also present the results of an AzTEC 0.15 deg^2 survey of the COSMOS field, which uncovers a significant over-density of bright SMGs that are spatially correlated to foreground mass structures, presumably as a result of gravitational lensing. Finally, I compare the results of the available SMG surveys completed to date and explore the effects of cosmic variance on the interpretation of individual surveys.

Inequality and City Size*

PubMed Central

Baum-Snow, Nathaniel; Pavan, Ronni

2013-01-01

Between 1979 and 2007 a strong positive monotonic relationship between wage inequality and city size has developed. This paper investigates the links between this emergent city size inequality premium and the contemporaneous nationwide increase in wage inequality. After controlling for the skill composition of the workforce across cities of different sizes, we show that at least 23 percent of the overall increase in the variance of log hourly wages in the United States from 1979 to 2007 is explained by the more rapid growth in the variance of log wages in larger locations relative to smaller locations. This influence occurred throughout the wage distribution and was most prevalent during the 1990s. More rapid growth in within skill group inequality in larger cities has been by far the most important force driving these city size specific patterns in the data. Differences in the industrial composition of cities of different sizes explain up to one-third of this city size effect. These results suggest an important role for agglomeration economies in generating changes in the wage structure during the study period. PMID:24954958

78 FR 32556 - Safety Zone; 2013 Ocean City Air Show, Atlantic Ocean; Ocean City, MD

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-31

...-AA00 Safety Zone; 2013 Ocean City Air Show, Atlantic Ocean; Ocean City, MD AGENCY: Coast Guard, DHS... navigable waters of the Atlantic Ocean in the vicinity of Ocean City, MD to support the Ocean City Air Show... June 9, 2013, Ocean City, MD will host an air show event between Talbot Street and 33rd Street over the...

75 FR 18778 - Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-13

...-AA00 Safety Zone; Ocean City Air Show 2010, Atlantic Ocean, Ocean City, MD AGENCY: Coast Guard, DHS... zone on the Atlantic Ocean in the vicinity of Ocean City, Maryland to support the Ocean City Air Show..., 5, and 6, 2010 Ocean City, Maryland will host an air show event on the Atlantic Ocean between Talbot...

City of Crystal City, Missouri - Clean Water Act Public Notice

EPA Pesticide Factsheets

The EPA is providing notice of proposed Administrative Penalty Assessment against the City of Crystal City, Missouri, a municipality located in Jefferson County, Missouri, 63019, for alleged violations associated with the City’s wastewater treatment progra

78 FR 38580 - Special Local Regulation; Tall Ships Celebration Bay City, Bay City, MI

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-27

...-AA08 Special Local Regulation; Tall Ships Celebration Bay City, Bay City, MI AGENCY: Coast Guard, DHS... regulatory act for the celebration specific to Bay City, MI, the Coast Guard recently published a separate... various events throughout the Great Lakes this summer, to include the Tall Ships Celebration Bay City...

Combined Effect of Long Processing Time and Na2SiF6 on the Properties of PEO Coatings Formed on AZ91D

NASA Astrophysics Data System (ADS)

Rehman, Zeeshan Ur; Koo, Bon Heun

2016-08-01

In this study, protective ceramic coatings were prepared on AZ91D magnesium alloy by plasma electrolytic oxidation (PEO) to improve the corrosion and mechanical properties of AZ91D magnesium alloy. The process was conducted in silicate-fluoride-based electrolyte solution. It was found that the average micro-hardness of the coating was significantly increased with an increase in the PEO processing time. The highest value of the average micro-hardness ~1271.2 HV was recorded for 60-min processing time. The phase analysis of the coatings indicated that they were mainly composed of Mg2SiO4, MgO, and MgF2 phases. The surface and cross-sectional study demonstrated that porosity was largely reduced with processing time, together with the change in pore geometry from irregular to spherical shape. The results of the polarization test in 3.5 wt.% NaCl solution revealed that aggressive corrosion took place for 5-min sample; however, the corrosion current was noticeably decreased to 0.43 × 10-7 A/cm2 for the 60-min-coated sample. The superior nobility and hardness for long processing time are suggested to be due to the dense and highly thick coating, coupled with the presence of MgF2 phase.

Towards the new urban agenda of safe cities: urban crimes in four Indonesian cities

NASA Astrophysics Data System (ADS)

Setiawan, B.

2017-12-01

As has stated in the Habitat III agreement, named as The New Urban Agenda/NUA, signed in Quito, Ecuador, October 2016, safe cities is one among important global goals that should be achieved in the next twenty years - safe city is defined generally by city that is equated with reduced violence on the one hand, and on the other, with reduced uncertainty. The fact that under a rapid urbanization and urban transformation in Indonesia, urban crimes tend to increase in many Indonesian cities questions whether Indonesian cities are ready to ensure the idea of safe city. This paper aims to document the incidents of urban crimes, spatial dimensions, the socio-factors and how local community responses to such crimes. It utilised a multiple case studies of four cities in Indonesia which are: Yogyakarta, Surabaya, Makasar, and Manado, Data and information for the paper were primarily collected through secondary data, but some field observations and interviews with stakeholders related to urban crimes in four cities were also conducted. The paper could be considered as a preliminary study to understand the urban crimes phenomena in Indonesia and finds that the incidents of urban crimes are fluctuated in four cities explored. It argues that there is a significant correlation between urban crimes incidents and spatial characteristics of the city.

Atypical Cities

ERIC Educational Resources Information Center

DiJulio, Betsy

2011-01-01

In this creative challenge, Surrealism and one-point perspective combine to produce images that not only go "beyond the real" but also beyond the ubiquitous "imaginary city" assignment often used to teach one-point perspective. Perhaps the difference is that in the "atypical cities challenge," an understanding of one-point perspective is a means…

78 FR 55757 - Notice of Determinations Regarding Eligibility To Apply for Worker Adjustment Assistance

Federal Register 2010, 2011, 2012, 2013, 2014

2013-09-11

... investigation resulting in-- (A) an affirmative determination of serious injury or threat thereof under section.......... May 16, 2012. Services and Manpower. 82,965 Key City Furniture, Inc Wilkesboro, NC...... August 7...., Aerotek, Tempe, AZ July 12, 2012. Manpower and Insight Global. 82,911 CompuCom Systems, Inc., Logistics...

Energy sustainable cities. From eco villages, eco districts towards zero carbon cities

NASA Astrophysics Data System (ADS)

Zaręba, Anna; Krzemińska, Alicja; Łach, Janusz

2017-11-01

Minimizing energy consumption is the effect of sustainable design technics as among many others: designing buildings with solar access and natural ventilation, using climate responsive design materials and effective insulation. Contemporary examples of zero-carbon cities: Masdar City, United Arab Emirates and Dongtan, China, confirm technical feasibility of renewable energy by implementation of solar PV and wind technologies. The ecological city - medium or high density urban settlement separated by greenspace causes the smallest possible ecological footprint on the surrounding countryside through efficient use of land and its resources, recycling used materials and converting waste to energy. This paper investigates the concept of energy sustainable cities, examines, how urban settlements might affect building energy design in eco-villages, eco-districts (e.g. Vauban, Freiburg in Germany, Bo01 Malmo in Sweden), and discuss the strategies for achieving Zero Emission Cities principles in densely populated areas. It is focused on low energy architectural design solutions which could be incorporated into urban settlements to create ecological villages, districts and cities, designed with consideration of environmental impact, required minimal inputs of energy, water, food, waste and pollution.

Big data, smart cities and city planning

PubMed Central

2013-01-01

I define big data with respect to its size but pay particular attention to the fact that the data I am referring to is urban data, that is, data for cities that are invariably tagged to space and time. I argue that this sort of data are largely being streamed from sensors, and this represents a sea change in the kinds of data that we have about what happens where and when in cities. I describe how the growth of big data is shifting the emphasis from longer term strategic planning to short-term thinking about how cities function and can be managed, although with the possibility that over much longer periods of time, this kind of big data will become a source for information about every time horizon. By way of conclusion, I illustrate the need for new theory and analysis with respect to 6 months of smart travel card data of individual trips on Greater London’s public transport systems. PMID:29472982

Big data, smart cities and city planning.

PubMed

Batty, Michael

2013-11-01

I define big data with respect to its size but pay particular attention to the fact that the data I am referring to is urban data, that is, data for cities that are invariably tagged to space and time. I argue that this sort of data are largely being streamed from sensors, and this represents a sea change in the kinds of data that we have about what happens where and when in cities. I describe how the growth of big data is shifting the emphasis from longer term strategic planning to short-term thinking about how cities function and can be managed, although with the possibility that over much longer periods of time, this kind of big data will become a source for information about every time horizon. By way of conclusion, I illustrate the need for new theory and analysis with respect to 6 months of smart travel card data of individual trips on Greater London's public transport systems.

Biodegradation behavior of micro-arc oxidized AZ31 magnesium alloys formed in two different electrolytes

NASA Astrophysics Data System (ADS)

Seyfoori, A.; Mirdamadi, Sh.; Khavandi, A.; Raufi, Z. Seyed

2012-11-01

Degradation behavior of coated magnesium alloys is among most prominent factors for their biomedical applications. In this study, bio-corrosion behavior of micro-arc oxidized magnesium AZ31 alloys formed in silicate and phosphate baths was investigated in r-SBF medium. For this purpose polarization behavior and open circuit profile of the coated samples were achieved by electrochemical and immersion tests, respectively. Moreover, the morphology and composition of the coatings were evaluated before and after immersion test using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results showed that the phosphate film had better corrosion resistance and greater thickness than silicate film and, in turn, the lesser degradability in SBF solution, so that Ca2+ and PO43- containing compounds were more abundant on silicate film than phosphate film. Moreover phosphate film had greater surface roughness and lesser hydrophilic nature.

Micro and sub-micron surface structuring of AZ31 by laser re-melting and dimpling

NASA Astrophysics Data System (ADS)

Furlan, Valentina; Demir, Ali Gökhan; Previtali, Barbara

2015-12-01

In this work, the use of ns-pulsed fibre laser for surface structuring of AZ31 Mg alloy is investigated. Surface re-melting was employed to change surface morphology, especially in terms of surface roughness. Dimpling by percussion microdrilling was investigated to control the hole geometry.. With surface remelting mono-directional and homogeneous surfaces were obtained with Fl<500 J/cm2. Above 500 J/cm2 particle generation was observed, which induced sub-micron structure growth with nano-fibrous features. Moreover, surface roughness could be controlled below the initial value and much higher. With dimpling, transformation from gentle to strong ablation was observed at F0=10.3 J/cm2. XRD analysis was employed to link oxide growth to the surface morphology. Tensile tests were carried out to assess the damage on the mechanical properties after surface structuring.

Salt Lake City, Utah

NASA Technical Reports Server (NTRS)

2002-01-01

Salt Lake City, Utah, will host the 2002 Winter Olympic Games. The city is located on the southeastern shore of the Great Salt Lake and sits to the west of the Wasatch Mountains, which rise more than 3,500 meters (10,000 feet) above sea level. The city was first settled in 1847 by pioneers seeking relief from religious persecution. Today Salt Lake City, the capital of Utah, is home to more than 170,000 residents. This true-color image of Salt Lake City was acquired by the Enhanced Thematic Mapper Plus (ETM+), flying aboard Landsat 7, on May 26, 2000. The southeastern tip of the Great Salt Lake is visible in the upper left of the image. The furrowed green and brown landscape running north-south is a portion of the Wasatch Mountains, some of which are snow-capped (white pixels). The greyish pixels in the center of the image show the developed areas of the city. A number of water reservoirs can be seen east of the mountain range. Salt Lake City International Airport is visible on the northwestern edge of the city. About 20 miles south of the airport is the Bingham Canyon Copper Mine (tan pixels), the world's largest open pit excavation. See also this MODIS image of Utah. Image courtesy NASA Landsat7 Science Team and USGS Eros Data Center

"TNOs are Cool": A survey of the trans-Neptunian region. XII. Thermal light curves of Haumea, 2003 VS2 and 2003 AZ84 with Herschel/PACS

NASA Astrophysics Data System (ADS)

Santos-Sanz, P.; Lellouch, E.; Groussin, O.; Lacerda, P.; Müller, T. G.; Ortiz, J. L.; Kiss, C.; Vilenius, E.; Stansberry, J.; Duffard, R.; Fornasier, S.; Jorda, L.; Thirouin, A.

2017-08-01

Context. Time series observations of the dwarf planet Haumea and the Plutinos 2003 VS2 and 2003 AZ84 with Herschel/PACS are presented in this work. Thermal emission of these trans-Neptunian objects (TNOs) were acquired as part of the "TNOs are Cool" Herschel Space Observatory key programme. Aims: We search for the thermal light curves at 100 and 160 μm of Haumea and 2003 AZ84, and at 70 and 160 μm for 2003 VS2 by means of photometric analysis of the PACS data. The goal of this work is to use these thermal light curves to obtain physical and thermophysical properties of these icy Solar System bodies. Methods: When a thermal light curve is detected, it is possible to derive or constrain the object thermal inertia, phase integral and/or surface roughness with thermophysical modeling. Results: Haumea's thermal light curve is clearly detected at 100 and 160 μm. The effect of the reported dark spot is apparent at 100 μm. Different thermophysical models were applied to these light curves, varying the thermophysical properties of the surface within and outside the spot. Although no model gives a perfect fit to the thermal observations, results imply an extremely low thermal inertia (<0.5 J m-2 s-1/2 K-1, hereafter MKS) and a high phase integral (>0.73) for Haumea's surface. We note that the dark spot region appears to be only weakly different from the rest of the object, with modest changes in thermal inertia and/or phase integral. The thermal light curve of 2003 VS2 is not firmly detected at 70 μm and at 160 μm but a thermal inertia of (2 ± 0.5) MKS can be derived from these data. The thermal light curve of 2003 AZ84 is not firmly detected at 100 μm. We apply a thermophysical model to the mean thermal fluxes and to all the Herschel/PACS and Spitzer/MIPS thermal data of 2003 AZ84, obtaining a close to pole-on orientation as the most likely for this TNO. Conclusions: For the three TNOs, the thermal inertias derived from light curve analyses or from the

Securing water for the cities.

PubMed

Satterthwaite, D

1993-01-01

Many cities in developing countries have grown so much that they can no longer provide adequate, sustainable water. Over pumping in Dakar and Mexico City has forced those cities to obtain water from ever more distant sources. In Dakar, the result has been saltwater intrusion. Overpumping has caused Mexico City to sink, in some areas by as much as 9 m, resulting in serious damage to buildings and sewage and drainage pipes. Other cities facing similar water problems are coastal cities in Peru (e.g., Lima), La Rioja and Catamarca in Argentina, cities in Northern Mexico, and cities in dry areas of Africa. For some cities, the problem is not so much ever more distant water supplies but insufficient funds to expand supplies. Bangkok and Jakarta both face saltwater intrusion into their overdrawn aquifers. Even through agriculture is the dominant user of water in most countries, demand concentrated in a small area exhausts local and regional sources and pollutes rivers, lakes, and coasts with untreated human and industrial waste. Most cities in Africa and Asia do not have a sewerage system. Further, most cities do not have the drains to deal with storm water and external floodwater, causing frequent, seasonal flooding. The resulting stagnant water provides breeding grounds for insect vectors of diseases (e.g., malaria). The problems in most cities are a result of poor management, not lack of water. Reducing leaks in existing piped distribution systems from the usual 60% loss of water to leaks to 12% would increase the available water 2-fold. Another way to address water shortages would be commercial, industrial, and recreational use of minimally treated waste water, such as is the case in Madras and Mexico City. Political solutions are needed to resolve inadequate water supply and waste management.

The Effect of Simulated Lunar Dust on the Absorptivity, Emissivity, and Operating Temperature on AZ-93 and Ag/FEP Thermal Control Surfaces

NASA Technical Reports Server (NTRS)

Gaier, James R.; Siamidis, John; Panko, Scott R.; Rogers, Kerry J.; Larkin, Elizabeth M. G.

2008-01-01

JSC-1AF lunar simulant has been applied to AZ-93 and AgFEP thermal control surfaces on aluminum or composite substrates in a simulated lunar environment. The temperature of these surfaces was monitored as they were heated with a solar simulator and cooled in a 30 K coldbox. Thermal modeling was used to determine the absorptivity ( ) and emissivity ( ) of the thermal control surfaces in both their clean and dusted states. Then, a known amount of power was applied to the samples while in the coldbox and the steady state temperatures measured. It was found that even a submonolayer of simulated lunar dust can significantly degrade the performance of both white paint and second-surface mirror type thermal control surfaces under these conditions. Contrary to earlier studies, dust was found to affect as well as . Dust lowered the emissivity by as much as 16 percent in the case of AZ-93, and raised it by as much as 11 percent in the case of AgFEP. The degradation of thermal control surface by dust as measured by / rose linearly regardless of the thermal control coating or substrate, and extrapolated to degradation by a factor 3 at full coverage by dust. Submonolayer coatings of dust were found to not significantly change the steady state temperature at which a shadowed thermal control surface will radiate.

Star and Dust Formation Activities in AzTEC-3, a Starburst Galaxy at z = 5.3

NASA Astrophysics Data System (ADS)

Dwek, Eli; Staguhn, Johannes G.; Arendt, Richard G.; Capak, Peter L.; Kovacs, Attila; Benford, Dominic J.; Fixsen, Dale; Karim, Alexander; Leclercq, Samuel; Maher, Stephen F.; Moseley, Samuel H.; Schinnerer, Eva; Sharp, Elmer H.

2011-09-01

Analyses of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. An important observational constraint neglected in the analysis is the mass of dust giving rise to the IR emission. In this paper we add this constraint to the analysis of AzTEC-3. Adopting an upper limit to the mass of stars and a bolometric luminosity for this object, we construct different stellar and chemical evolutionary scenarios, constrained to produce the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. We use the PÉGASE population synthesis code and a chemical evolution model to follow the evolution of the galaxy's SED and its stellar and dust masses as a function of galactic age for seven different stellar initial mass functions (IMFs). We find that the model with a Top Heavy IMF provided the most plausible scenario consistent with the observational constraints. In this scenario the dust formed over a period of ~200 Myr, with an SFR of ~500 M sun yr-1. These values for the age and SFR in AzTEC-3 are significantly higher and lower, respectively, from those derived without the dust mass constraint. However, this scenario is not unique, and others cannot be completely ruled out because of the prevailing uncertainties in the age of the galaxy, its bolometric luminosity, and its stellar and dust masses. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.

STAR AND DUST FORMATION ACTIVITIES IN AzTEC-3, A STARBURST GALAXY AT z = 5.3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dwek, Eli; Staguhn, Johannes G.; Arendt, Richard G.

2011-09-01

Analyses of high-redshift ultraluminous infrared (IR) galaxies traditionally use the observed optical to submillimeter spectral energy distribution (SED) and estimates of the dynamical mass as observational constraints to derive the star formation rate (SFR), the stellar mass, and age of these objects. An important observational constraint neglected in the analysis is the mass of dust giving rise to the IR emission. In this paper we add this constraint to the analysis of AzTEC-3. Adopting an upper limit to the mass of stars and a bolometric luminosity for this object, we construct different stellar and chemical evolutionary scenarios, constrained to producemore » the inferred dust mass and observed luminosity before the associated stellar mass exceeds the observational limit. We use the PEGASE population synthesis code and a chemical evolution model to follow the evolution of the galaxy's SED and its stellar and dust masses as a function of galactic age for seven different stellar initial mass functions (IMFs). We find that the model with a Top Heavy IMF provided the most plausible scenario consistent with the observational constraints. In this scenario the dust formed over a period of {approx}200 Myr, with an SFR of {approx}500 M{sub sun} yr{sup -1}. These values for the age and SFR in AzTEC-3 are significantly higher and lower, respectively, from those derived without the dust mass constraint. However, this scenario is not unique, and others cannot be completely ruled out because of the prevailing uncertainties in the age of the galaxy, its bolometric luminosity, and its stellar and dust masses. A robust result of our models is that all scenarios require most of the radiating dust mass to have been accreted in molecular clouds. Our new procedure highlights the importance of a multiwavelength approach, and of the use of dust evolution models in constraining the age and the star formation activity and history in galaxies.« less

Half the world in cities.

PubMed

Souza, J B

1980-06-01

City planners have exacerbated the problems connected with urbanization in Third World countries. Lower socioeconomic groups have moved from rural areas to the cities because they see greater employment, educational, and health opportunities there. These poor people must be provided for in the cities. But provision for these people cannot include allowing pollution and congestion to fester. Neither will urban renewal which merely displaces the poor (who, in fact, provide necessary services for the city) answer the problem. City managers do not pay enough attention to the poorer, more congested areas of their cities. Zoning policies actually seem to be outmoded and to do harm to city populations by increasing the time required for people to shop and commute to work. The walled city of Delhi, India, is cited as an example of a settlement where the population's convenience has been considered. Regulations must be changed to facilitate land ownership by the poorer groups. These practical policies are preferable to bulldozer or rural migration bans.

City-Level Energy Decision Making. Data Use in Energy Planning, Implementation, and Evaluation in U.S. Cities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aznar, Alexandra; Day, Megan; Doris, Elizabeth

2015-07-08

The Cities-LEAP technical report, City-Level Energy Decision Making: Data Use in Energy Planning, Implementation, and Evaluation in U.S. Cities, explores how a sample of cities incorporates data into making energy-related decisions. This report provides the foundation for forthcoming components of the Cities-LEAP project that will help cities improve energy decision making by mapping specific city energy or climate policies and actions to measurable impacts and results.