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1

78 FR 71706 - Noise Exposure Map Notice for Laughlin/Bullhead International Airport, Bullhead City, Arizona  

Federal Register 2010, 2011, 2012, 2013, 2014

...Aviation Administration Noise Exposure Map Notice for Laughlin/Bullhead International...its determination that the noise exposure maps submitted by Mohave County Airport Authority...that the FAA finds that the noise exposure maps submitted for Laughlin/Bullhead...

2013-11-29

2

33 CFR 100.1102 - Annual marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...  

Code of Federal Regulations, 2013 CFR

...marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona) within the San Diego Captain...marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate...

2013-07-01

3

77 FR 70121 - Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Special Local Regulation; Annual Marine Events on the Colorado River Between Davis Dam (Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of the Port Zone AGENCY: Coast Guard, DHS. ACTION: Notice of enforcement of...

2012-11-23

4

77 FR 67563 - Special Local Regulation; Annual Marine Events on the Colorado River, Between Davis Dam (Bullhead...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Bullhead City, AZ) and Headgate Dam (Parker, AZ) Within the San Diego Captain of...Regatta, on the waters of Lake Moovalya, Parker, Arizona, from November 23 through November...regulations in that portion of Lake Moovalya, Parker, AZ between the northern and...

2012-11-13

5

33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...  

Code of Federal Regulations, 2014 CFR

...05?N, 114°38?20? W. 2. Laughlin/Bullhead City Rockets Over the River Fireworks Sponsor Laughlin Tourism Committee. Event Description Fireworks Display. Two events over the 4th of July Weekend. One will be on the 4th...

2014-07-01

6

33 CFR 100.1102 - Annual marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...  

Code of Federal Regulations, 2012 CFR

Annual marine events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam (Parker, Arizona) within the San Diego Captain of the Port Zone. 100.1102 Section 100.1102 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND...

2012-07-01

7

78 FR 17097 - Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...1625-AA00 Safety Zone; Lake Havasu Triathlon; Lake Havasu City, AZ AGENCY: Coast...London Bridge Channel for the Lake Havasu Triathlon. This temporary safety zone is necessary...date. B. Basis and Purpose The Havasu Triathlon will consist of 600 participants....

2013-03-20

8

78 FR 17869 - Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu City, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...USCG-2013-0005] RIN 1625-AA00 Safety Zone; Desert Storm Shootout; Lake Havasu, Lake Havasu...Havasu City, Arizona in support of the Desert Storm Shootout. This temporary safety...Lake Racer LLC is sponsoring the Desert Storm Shootout, which is to be held...

2013-03-25

9

Habitat Suitability Index Models: Black Bullhead  

USGS Publications Warehouse

This is one of a series of publications that provide information on the habitat requirements of selected fish and wildlife species. Literature describing the relationship between habitat variables related to life requisites and habitat suitability for the Black bullhead (Ictalurus melas) are synthesized. These data are subsequently used to develop Habitat Suitability (HIS) models. The HSI models are designed to provide information that can be used in impact assessment and habitat management.

Stuber, Robert J.

1982-01-01

10

Altered glutathione S-transferase catalytic activities in female brown bullheads from a contaminated central Florida lake  

Microsoft Academic Search

Brown bullheads (Ameriurus nebulosus) are a demersal freshwater species that can be found in a number of polluted ecosystems. The purpose of the present study was to determine the overall capacity for in vitro glutathione S-transferase (GST) detoxification by brown bullheads, and to see if bullhead GST catalysis was altered in bullheads from a polluted site. Brown bullhead liver cytosolic

E. P Gallagher; K. M Sheehy

2000-01-01

11

Phoenix, AZ, USA  

NASA Technical Reports Server (NTRS)

The city of Phoenix, AZ (33.5N, 112.0W) can be seen in good detail in this color infrared scene. Situated among truck crop agriculture fields, the color infrared photo depicts the vegetated fields as shades of red making the agriculture stand out in this desert environment. To the east, Lake Theodore Roosevelt and dam can be easily seen.

1973-01-01

12

HISTORICAL MONITORING OF BIOMARKERS OF EXPOSURE OF BROWN BULLHEAD  

EPA Science Inventory

Biomarkers of exposure to chemical contamination, benzo(a)pyrene (BAP) and naphthalene (NAPH) type metabolites were measured in brown bullhead from a heavily polycyclic aromatic hydrocarbon (PAH) contaminated section of the Black River, Ohio during and immediately after remedial ...

13

INITIAL AND SURVIVAL OF BlUEGILLS AND BLACK BULLHEADS STOCKED WITH LARGEMOUTH BASS  

E-print Network

estimated for bluegills (Lepomis macrochirus) and black bullheads (Ictalurus melas) stocked simultaneously (Lepomis macrochirus) and black bullhead (Ictalurus melas) first year growth mUltiple regression tests ¡ ¡ . ¡ . 2. Mean first year survival rates of bluegills (Lepomis macrochirus) and black bullheads (Ictalurus

14

Nightlife A-Z  

NSDL National Science Digital Library

Nightlife A-Z provides links to entertainment, shopping, and hotel directories for cities from Akron to Zurich. Handy if you're planning to visit any of these 130 cities in the U.S., Europe, or Asia. Provided by ENN (Entertainment Network News), the site also offers the latest entertainment news and an index to movies, kids links, comedy clubs, coffee pages, among many others. Proceeds from page sponsors go to the National Children's Coalition. http://www.sftoday.com/enn2/nitelife.htm

15

Pollution-induced behavioural effects in the brown bullhead (Ameiurus nebulosus)  

E-print Network

Pollution-induced behavioural effects in the brown bullhead (Ameiurus nebulosus) Ross D. Breckels on biodiversity. Thus, it is important to understand the nature of pollution- induced change in aquatic ecosystems. We show that brown bullheads (Ameiurus nebulosus) may have evolved in response to chronic pollution

Neff, Bryan D.

16

A potential biomarker of androgen exposure in European bullhead (Cottus sp.) kidney  

E-print Network

A potential biomarker of androgen exposure in European bullhead (Cottus sp.) kidney MĂŠlanie-structure of the kidney was characterized to identify normal structure of this organ, and histological changes previously described in the kidney of breeding male bullheads were quantified using the Kidney Epithelium Height (KEH

Paris-Sud XI, UniversitĂŠ de

17

Physicochemical and Biological Influences on Black Bullhead Populations in Eastern South Dakota Glacial Lakes  

Microsoft Academic Search

Lake and fish survey data (1991–1992) were compiled for 23 eastern South Dakota natural lakes to provide a basis for preliminary investigation of black bullhead (Ameiurus melas) populations. Survey data contained numerous physical and chemical variables describing lake environments and relative abundance and sue structure of the primary fish species present. Analyses indicated that abundance of black bullheads increased with

Michael L. Brown; David W. Willis; Brian G. Blackwell

1999-01-01

18

Comparative metabolism of benzo[a]pyrene by liver microsomes of channel catfish and brown bullhead  

SciTech Connect

The authors investigated the metabolism of the carcinogen benzo[a]pyrene (BaP) by liver microsomes of channel catfish (Ictalurus punctatus) and brown bullhead (Ameiurus nebulosus) pretreated with 3-methylcholanthrene. The catfish liver microsomes metabolized BaP at a considerably lower rate than did the brown bullhead liver microsomes. Although the BaP metabolites produced by the liver microsomes of the two species were qualitatively similar, there were considerable differences in the relative proportions of individual metabolites formed. The catfish liver microsomes produced a considerably lower proportion of benzo-ring diols of BaP including BaP-7,8-diol (the proximate carcinogenic metabolite of BaP) than did the bullhead liver microsomes. Compared to the bullhead liver microsomes, the catfish microsomes converted a higher proportion of BaP to phenolic metabolites.

Yuan, Z.X.; Kumar, S.; Sikka, H.C. [State Univ. of New York Coll., Buffalo, NY (United States). Environmental Toxicology and Chemistry Lab.

1997-04-01

19

Induction of Glutathione S-transferase Activity and Protein Expression in Brown Bullhead (Ameiurus nebulosus) Liver by Ethoxyquin  

Microsoft Academic Search

The inducibility of hepatic cytosolic glutathione S-transferases (GSTs) was examined in brown bullheads, a freshwater fish that is highly susceptible to hepatic neoplasia following exposure to car- cinogen-contaminated sediments. Juvenile bullheads were fed a semi-purified antioxidant-free diet supplemented with ethoxyquin (0.5% w\\/w dissolved in 3% corn oil), a prototypical rodent GST- inducing agent, twice daily for 14 days. Control bullheads

Kristin L. Henson; Gregory Stauffer

2001-01-01

20

Ontogenetic Microhabitat Shifts in the Bullhead, Cottus gobio L.,in a Fast Flowing Stream  

NASA Astrophysics Data System (ADS)

We investigated differences in microhabitat preference curves for bullheads, Cottus gobio L., of different size-classes during low flow periods, and evaluated the influence of such differences on habitat use through Weighted Usable Area (WUA) predictions in relation to river flow in a piedmont stream in Southwest France. Water depth, current velocity, and substratum composition were used to calculate proportional use values for each size-class (SC), and to quantify size-specific microhabitat preferences. Bullhead used non-cohesive and coarse mineral particles (pebbles, cobbles, boulders), but there was a spatial segregation of individuals from different size classes (SC1-SC4). Smaller bullhead (SC1, total length <60 mm) took refuge under cobbles, significantly preferred shallower areas, and were less prone to select high current velocities than larger bullhead (SC 2 to 4, >60 mm), the latter occurring below (or under) the largest particles, where current velocity is weakened and sand accumulates. SC1 bullhead had a more restricted range for each habitat descriptors, and were thus likely to require a more specific habitat type than other bullhead. The maximum WUA values and the related preferred discharges (0.15-0.75 m3 s-1) depended on the considered size-class. Our results suggest that ontogenetic niche shifts may play a role in the structure and dynamics of populations, by adjusting species' requirements to the spatial and temporal dynamics of environmental conditions, including abiotic and biotic conditions.

Legalle, Milčne; Mastrorillo, Sylvain; Santoul, Frédéric; Céréghino, Régis

2005-06-01

21

Mechanisms of density dependence in stream fish: exploitation competition for food reduces growth of adult European bullheads ( Cottus gobio )  

Microsoft Academic Search

In field experiments using cage enclosures, exploitation competition for invertebrate prey reduced individual growth of adult European bullheads (Cottus gobio) despite a dietary shift that maintained total prey biomass consump- tion. Growth of bullheads was negatively density dependent over a range of densities found in the field and total bio- mass production per enclosure was unrelated to stocking density. Individuals

Andrew J. H. Davey; George F. Turner; Stephen J. Hawkins; C. Patrick Doncaster

2006-01-01

22

Brown Bullhead as an Indicator Species: Seasonal Movement Patterns and Home Ranges within the Anacostia River, Washington, D.C  

Microsoft Academic Search

Elevated liver and skin tumor prevalence has been reported in brown bullhead Ameiurus nebulosus from the tidal Anacostia River, Washington, D.C. Movement data are needed to effectively use tumor prevalence as an indicator of habitat quality. We used ultrasonic telemetry to verify the residency of 40 adult brown bullheads (250–310 mm total length) in the Anacostia River during summer 2000,

Peter C. Sakaris; Roman V. Jesien; Alfred E. Pinkney

2005-01-01

23

In vitro kinetics of hepatic glutathione s-transferase conjugation in largemouth bass and brown bullheads  

SciTech Connect

The kinetics of glutathione 5-transferase (GST) catalysis were investigated in largemouth bass (Micropterus salmoides) and brown bullheads (Amerius nebulosus), two freshwater fish species found in a variety of polluted waterways in the eastern US. The initial rates of hepatic GST activity toward four GST substrates, including 1-chloro-2,4-dinitrobenzene, ethacrynic acid, {Delta}5-androstene-17-dione, and nitrobutyl chloride, were significantly higher in brown bullheads than in largemouth bass. Hepatic GST activity toward 1,2-dichloro-4-nitrobenzene, a {mu}-class GST substrate in rodents, was not detectable in either species. Liver cytosolic GSTs were more efficient in bullheads than in bass at catalyzing 1-chloro-2,4-dinitrobenzene-reduced glutathione (CDNB-GSH) conjugation over a broad range of electrophile (CDNB) concentrations, including those representative of environmental exposure. In contrast, largemouth bass maintained higher ambient concentrations of GSH, the nucleophilic cofactor for GST-mediated conjugation, than brown bullheads. Biphasic kinetics for GST-CDNB conjugation under conditions of variable GSH concentration were apparent in Eadie-Hofstee plots of the kinetic data, suggesting the presence of at least two hepatic GST isozymes with markedly different K{sub m} values for GSH in both species. The GST-CDNB reaction rate data obtained under conditions of variable GSH were well fitted (R{sup 2} = 0.999) by the two-enzyme Michaelis-Menten equation. In addition, Western blotting experiments confirmed the presence of two different hepatic GST-like proteins in both largemouth bass and brown bullhead liver. Collectively, these findings indicate that largemouth bass and brown bullhead GSTs catalyze the conjugation of structurally diverse, class-specific GST substrates, and that brown bullheads exhibit higher initial rates of GST activity than largemouth bass. The relatively higher rates of in vitro liver GST activity at the low substrate concentrations relevant to environmental exposure is expected to protect brown bullheads from the toxic effects of sediment-associated electrophilic chemicals. The somewhat lower rates of GST activity in largemouth bass liver compared with brown bullhead liver, however, may be offset by maintenance of higher ambient hepatic GSH concentrations in largemouth bass.

Gallagher, E.P.; Sheehy, K.M.; Lame, M.W.; Segall, H.J.

2000-02-01

24

Variable growth and longevity of yellow bullhead (Ameiurus natalis) in the Everglades of south Florida, USA  

USGS Publications Warehouse

Yellow bullhead (Ictaluridae: Ameiurus natalis) is the most abundant ictalurid catfish in the Everglades of southern Florida, USA, and, as both prey and predator, is one of many essential components in the ecological-simulation models used in assessing restoration success in the Everglades. Little is known of its biology and life history in this southernmost portion of its native range; the present study provides the first estimates of age and growth from the Everglades. In total, 144 yellow bullheads of 97-312 mm total length (TL) were collected from canals and marshes of the Everglades between April 2000 and January 2001, and from October 2003 to February 2005. Fish were aged using cross-sections of pectoral spines and ranged from 1-12 years, with the maximum age almost twice that of any yellow bullhead previously reported. Yellow bullheads from south Florida grew relatively rapidly during their first 3 years, but after age 5 growth slowed and fish approached an asymptote of ???214 mm TL. Compared to other populations in the United States, yellow bullhead in the Everglades grew relatively slowly, were smaller at age overall, but survived to older ages. ?? 2009 Blackwell Verlag GmbH.

Murie, D.J.; Parkyn, D.C.; Loftus, W.F.; Nico, L.G.

2009-01-01

25

Decreased glutathione S-transferase expression and activity and altered sex steroids in Lake Apopka brown bullheads (Ameriurus nebulosus)  

USGS Publications Warehouse

A number of freshwater lakes and reclaimed agricultural sites in Central Florida have been the receiving waters for agrochemical and municipal runoff. One of these sites, Lake Apopka, is also a eutrophic system that has been the focus of several case studies reporting altered reproductive activity linked to bioaccumulation of persistent organochlorine chemicals in aquatic species. The present study was initiated to determine if brown bullheads (Ameriurus nebulosus) from the north marsh of Lake Apopka (Lake Apopka Marsh) exhibit an altered capacity to detoxify environmental chemicals through hepatic glutathione S-transferase (GST)-mediated conjugation as compared with bullheads from a nearby reference site (Lake Woodruff). We also compared plasma sex hormone concentrations (testosterone, 17-?? estradiol, and 11 keto-testosterone) in bullheads from the two sites. Female bullheads from Lake Apopka had 40% lower initial rate GST conjugative activity toward 1-chloro-2,4-dinitrobenzene (CDNB), 50% lower activity towards p-nitrobutyl chloride (NBC), 33% lower activity toward ethacrynic acid (ECA), and 43% lower activity toward ??5-androstene-3,17-dione (??5-ADI), as compared with female bullheads from Lake Woodruff. Enzyme kinetic analyses demonstrated that female bullheads from Lake Apopka had lower GST-catalyzed CDNB clearance than did female Lake Woodruff bullheads. Western blotting studies of bullhead liver cytosolic proteins demonstrated that the reduced GST catalytic activities in female Lake Apopka bullheads were accompanied by lower expression of hepatic GST protein. No site differences were observed with respect to GST activities or GST protein expression in male bullheads. Female Lake Apopka bullheads also had elevated concentrations of plasma androgens (testosterone and 11-ketotestosterone) as compared with females from Lake Woodruff. In contrast, male Lake Apopka bullheads had elevated levels of plasma estrogen but similar levels of androgens as compared with male bullheads from Lake Woodruff. Collectively, our studies indicate the presence of reduced GST protein expression, reduced GST conjugative capacity and altered sex steroid homeostasis in female bullheads from a contaminated field site in Central Florida. The implications of these physiological alterations in terms of pollutant biotransformation and reproduction are discussed. ?? 2001 Elsevier Science B.V. All rights reserved.

Gallagher, E.P.; Gross, T.S.; Sheehy, K.M.

2001-01-01

26

Corrosion behaviour of AZ21, AZ501 and AZ91 in sodium chloride  

Microsoft Academic Search

The corrosion behaviour of AZ21, AZ501 and AZ91 was studied in 1 N NaCl at pH 11 by measuring electrochemical polarization curves, electrochemical AC impedance spectroscopy (EIS) and simultaneously measuring the hydrogen evolution rate and the magnesium dissolution rate. The corrosion rates increased in the following order: AZ501< AZ21< AZ91. The corrosion behaviour was related to alloy microstructure as revealed

Guangling Song; Andrej Atrens; Xianliang Wu; Bo Zhang

1998-01-01

27

Genetic analysis of potential postglacial watershed crossings in Central Europe by the bullhead (Cottus gobio L.).  

PubMed

Natural colonizations across watersheds have been frequently proposed to explain the present distributions of many freshwater fish species. However, detailed studies of such potential watershed crossings are still missing. Here, we investigated potential postglacial watershed crossings of the widely distributed European bullhead (Cottus gobio L.) in two different areas along the Rhine-Rhône watershed using detailed genetic analysis. The main advantage of studying bullheads vs. other freshwater fish species is that their distribution has been lightly influenced by human activities and as such, interpretations of colonization history are not confounded by artificial transplantations. The genetic analyses of eight microsatellite loci revealed strong genetic similarities between populations of both sides of the Rhine-Rhône watershed in the Lake Geneva area, giving strong evidence for a natural watershed crossing of bullheads from the upper Rhine drainage into the Rhône drainage in the Lake Geneva area likely facilitated by the retreat of the glaciers after the last glacial maximum some 20,000 years ago. Populations from the Lake Geneva basin were genetically more similar to populations from across the watershed in the upper Rhine drainage than to populations further downstream in the lower Rhône. In contrast, populations from Belfort, an area, which was not covered by ice during the last glacial maximum, showed strong genetic differentiation between populations of the upper Rhine and Rhône drainages. Based on our results on the bullhead, we propose that glacial retreat may have eased the dispersal of numerous European freshwater fish species across several geological boundaries. PMID:17908217

Vonlanthen, P; Excoffier, L; Bittner, D; Persat, H; Neuenschwander, S; Largiadčr, C R

2007-11-01

28

Genetic analysis of potential postglacial watershed crossings in Central Europe by the bullhead (Cottus gobio L.)  

Microsoft Academic Search

Natural colonizations across watersheds have been frequently proposed to explain the present distributions of many freshwater fish species. However, detailed studies of such potential watershed crossings are still missing. Here, we investigated potential postglacial watershed crossings of the widely distributed European bullhead (Cottus gobio L.) in two different areas along the Rhine-Rhône watershed using detailed genetic analysis. The main advantage

P. VONLANTHEN; L. EXCOFFIER; D. BITTNER; H. PERSAT; S. NEUENSCHWANDER; C. R. LARGIADČR

2007-01-01

29

SYNCHRONOUS FLUOROMETRIC MEASUREMENT OF METABOLITES OF POLYCYCLIC AROMATIC HYDROCARBONS IN THE BILE OF BROWN BULLHEAD  

EPA Science Inventory

A synchronous fluorescent spectroscopy (SFS) method was developed to measure pyrene-type metabolites in the bile of brown bullhead (Ameiurus nebulosus) and to estimate the exposure of fish to PAHs in four Lake Erie tributaries collected in the spring and fall of 1990 and 1991. Fo...

30

Tumor prevalence and biomarkers of genotoxicity in brown bullhead ( Ameiurus nebulosus) in Chesapeake Bay tributaries  

Microsoft Academic Search

We surveyed four Chesapeake Bay tributaries for skin and liver tumors in brown bullhead (Ameiurus nebulosus). We focused on the South River, where the highest skin tumor prevalence (53%) in the Bay watershed had been reported. The objectives were to 1) compare tumor prevalence with nearby rivers (Severn and Rhode) and a more remote river (Choptank); 2) investigate associations between

Alfred E. Pinkney; John C. Harshbarger; Natalie K. Karouna-Renier; Kathryn Jenko; Lennart Balk; Halldóra Skarphéđinsdóttir; Birgitta Liewenborg; Michael A. Rutter

2011-01-01

31

Induction of micronuclei and nuclear abnormalities in the erythrocytes of mudminnows ( Umbra limi ) and brown bullheads ( Ictalurus nebulosus )  

Microsoft Academic Search

The authors are interested in determining whether the MN technique can be developed as an in situ assay for genotoxicity in fish species; and in particular, the brown bullhead (Ictalurus nebulosus). In this study, central mudminnows (Umbra limi) and brown bullheads were exposed to EMS and benzo(a)pyrene (BaP) by intraperitoneal injection. The various experiments were designed to: i) compare the

C. D. Metcalfe

1988-01-01

32

DNA damage and external lesions in brown bullheads (Ameiurus nebulosus) from contaminated habitats  

USGS Publications Warehouse

The Comet assay was used to compare levels of DNA damage in brown bullheads (Ameiurus nebulosus) collected from three known contaminated locations, the Cuyahoga River (OH, USA), Ashtabula River (OH, USA; both tributaries to Lake Erie, USA), and Ashumet Pond (Cape Cod, MA, USA), with brown bullheads collected from three paired reference sites, Old Woman Creek (OH, USA), Conneaut River (OH, USA; both tributaries to Lake Erie), and Great Herring Pond (mainland MA, USA), respectively. Blood was sampled from each fish, and the Comet assay was conducted on erythrocytes. The assay results demonstrate that fish from the three contaminated sites each suffered higher DNA damage compared with fish from their respective reference sites. The results also show that the genetic damage was associated with the occurrence of external lesions and deformities in fish. The Comet assay is sufficiently sensitive to detect exposure of natural fish populations to environmental levels of genotoxic contaminants. ?? 2006 SETAC.

Yang, X.; Meier, J.; Chang, L.; Rowan, M.; Baumann, P.C.

2006-01-01

33

Biological effects of chronic exposure to low-level radiation in bullhead catfish ({\\\\it Ameiurus natalis\\\\\\/})  

Microsoft Academic Search

Free-ranging animals that inhabit contaminated environments provide unique opportunities to evaluate the effects of contaminant exposure. In this case, yellow bullhead catfish (Ameiurus natalis) were used as biomonitors of low-level environmental radiation exposure. Biomarkers of oxidative damage, namely pronephric pigmented macrophages (PMs) and the oxidative DNA adduct 8-hydroxy-deoxyguanosine (8-OH-dG) were related to $\\\\sp{137}$Cs burdens of fish inhibiting an abandoned reactor

Clark Desmond McCreedy

1996-01-01

34

Novel and optimized polymorphic microsatellite loci for brown bullhead ( Ameiurus nebulosus )  

Microsoft Academic Search

Eight novel polymorphic microsatellite markers were developed for brown bullhead (Ameiurus nebulosus). Allelic diversity varied between three and eleven alleles per locus with observed heterozygosity ranging from 0.286 to\\u000a 0.776 among 49 Detroit River fish, with no evidence of linkage disequilibrium. One locus showed deviation from Hardy-Weinberg\\u000a equilibrium likely due to null alleles. The new markers amplified in four related

L. I. SoderbergJ; J. A. Galarza; D. D. Heath

2010-01-01

35

Bioaccumulation of cesium-137 in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned nuclear reactor reservoir  

Microsoft Academic Search

Bioaccumulation of š³⁡Cs was investigated in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned reactor reservoir, Pond B, Savannah River Site, Barnwell Co., South Carolina. The authors collected fish by trap-netting, and determined ages from pectoral spines. Muscle and other tissues were assayed for š³⁡Cs by NaI-scintillation. Music š³⁡Cs was unrelated to sex or mass of fish, but was related

Clark D. McCreedy; L. T. Glickman; C. H. Jagoe; I. Lehr Brisbin

1997-01-01

36

Tumor prevalence and biomarkers in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River watershed [poster  

USGS Publications Warehouse

Associations between contaminant exposure and liver and skin tumor prevalence were evaluated in brown bullheads (Ameiurus nebulosus) from the tidal Potomac River watershed. Thirty bullheads (>260 mm) were collected from (1) Quantico embayment, near a Superfund site which released organochlorine contaminants; (2) Neabsco Creek, a tributary with petroleum inputs from runoff and marinas; and (3) Anacostia River (spring and fall), an urban tributary designated as a Chesapeake Bay Region of Concern, contaminated with PCBs, PAHs, and organochlorine pesticides. Fish were collected from the Tuckahoe River, as a reference. Cytochrome P450 activity, bile PAH metabolites, and muscle organochlorine pesticide/PCB concentrations were measured in randomly-selected individuals and sediment contaminants were analyzed. We found statistically significant differences in liver tumor prevalences: Anacostia (spring)-50%, Anacostia (fall)-60%, Neabsco-17%, Quantico-7%, Tuckahoe-10%. Skin tumor prevalences were significantly different: Anacostia (spring)-37%, Anacostia (fall)-10%, Neabsco-3%, Quantico-3%, Tuckahoe-0%. Tumor prevalence in Anacostia bullheads warrants concern and was similar to those at highly contaminated sites in the Great Lakes. There was evidence of higher PAH exposure in Anacostia fish but a cause-effect linkage cannot be established. Fish tumor surveys, with histopathological examination of internal and external organs, are recommended for monitoring the status of Regions of Concern.

Mitchell, R.T.

2000-01-01

37

Temperament in bullheads: do laboratory and field explorative behaviour variables correlate?  

NASA Astrophysics Data System (ADS)

The relevance of temperament traits for life history strategy or productivity is increasingly acknowledged. Temperament traits are often either observed in captivity or in the wild, but studies combining both observations are very rare. We examine whether exploratory behaviour in the bullhead ( Cottus perifretum), assayed under laboratory conditions, predicts this behaviour under field conditions. Forty-three PIT-tagged individuals were first assayed for exploration of a novel environment in the aquarium and then released into an unfamiliar stream stretch, where they were later relocated using a mobile antenna. Explorative behaviour assayed in the laboratory was significantly positively related to the exploration in the field, thus predicting distance moved in the field release. Both in the laboratory and in the field, explorative behaviour was not related to individual body length. When bullheads that did not leave the refuge in the aquarium (laboratory assay) and, therefore, did not explore the new environment were excluded from the analysis, the correlation between laboratory and field explorative behaviour variables became weaker. However, overall, our results illustrate that exploration rate of bullheads in isolated single-individual experiments can be used to predict this behaviour in the natural ecosystem.

Kobler, Alexander; Engelen, Brecht; Knaepkens, Guy; Eens, Marcel

2009-10-01

38

Mortality and pathology in brown bullheads Amieurus nebulosus associated with a spontaneous Edwardsiella ictaluri outbreak under tank culture conditions  

USGS Publications Warehouse

Brown bullheads Amieurus nebulosus (family Ictaluridae) are commonly used as a sentinel of environmental contamination. These fish are not generally cultured under laboratory conditions and little is known about their disease susceptibility. Here we report an outbreak of disease due to Edwardsiella ictaluri in a laboratory population of tank-reared, wild-caught brown bullheads. The isolate was positively identified as E. ictaluri using standard bacteriological substrate utilization tests and a monoclonal antibody specific for this bacterium. This pathogen causes a significant disease in channel catfish Ictalurus punctatus and is associated with disease in other ictalurid and non-ictalurid fishes. It appears that E. ictaluri is also a significant pathogen in brown bullheads and produces clinical signs and lesions similar but not identical to those observed in channel catfish. Since commercial sources of bullheads for laboratory tank studies are not available, precautions should be taken to prevent potential E. ictaluri disease outbreaks from wild-caught bullheads intended for laboratory research. ?? Inter-Research 2006.

Iwanowicz, L.R.; Griffin, A.R.; Cartwright, D.D.; Blazer, V.S.

2006-01-01

39

Induction of micronuclei and nuclear abnormalities in the erythrocytes of mudminnows (Umbra limi) and brown bullheads (Ictalurus nebulosus)  

SciTech Connect

The authors are interested in determining whether the MN technique can be developed as an in situ assay for genotoxicity in fish species; and in particular, the brown bullhead (Ictalurus nebulosus). In this study, central mudminnows (Umbra limi) and brown bullheads were exposed to EMS and benzo(a)pyrene (BaP) by intraperitoneal injection. The various experiments were designed to: i) compare the sensitivity of the MN and SCE assays using the mudminnow model; ii) determine whether MN are induced in the erythrocytes of the brown bullhead by exposure to genotoxic chemicals (EMS and BaP); iii) determine whether erythrocytes harvested from the erythropoietic tissues of fish (pronephros) have a greater incidence of MN than peripheral erythrocytes; iv) examine the association between the induction of MN and the induction of nuclear abnormalities in erythrocytes after exposure of genotoxic agents.

Metcalfe, C.D.

1988-04-01

40

Aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, Ameiurus nebulosus  

USGS Publications Warehouse

The brown bullhead Ameiurus nebulosus is a species of the family Ictaluridae commonly used as a sentinel of environmental contamination. While these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (PCBs), few controlled, laboratory-based studies have been designed to document the effects of PCB mixtures in this species. Here, brown bullhead were exposed to the PCB mixture, Aroclor 1248, via intraperitoneal injection and the effects on immune function, plasma hormones and disease resistance were evaluated. Exposure to this mixture led to a decrease in bactericidal activity and circulating antibodies to Edwardsiella ictaluri present from a previous exposure to this pathogen. A subsequent E. ictaluri disease challenge led to significantly higher mortality in A1248 treated fish compared to vehicle-control fish. The mitogenic response to the T-cell mitogen, phytohemaglutinin-P, was increased compared to vehicle-control fish. The steroid hormone, cortisol, and the thyroid hormone, T3, were also significantly lower in A1248 exposed fish. In summary, we have validated a number of functional immune assays for application in brown bullhead immunotoxicity studies. Additionally, we have demonstrated that the PCB mixture (A1248) modulates both immune function and endocrine physiology in brown bullhead. Such data may compliment the interpretation of data yielded from applied field studies conducted in PCB contaminated aquatic ecosystems.

Iwanowicz, L.R.; Blazer, V.S.; McCormick, S.D.; Van Veld, P.A.; Ottinger, C.A.

2009-01-01

41

ISOFORMS OF APOLIPOPROTEIN A-I IN THE SERUM OF BROWN BULLHEADS (AMEIURUS NEBULOSUS) WITH LIVER CANCER  

EPA Science Inventory

1. Serum samples from 10 tumor-bearing (all fish with cholangiocellular carcinomas, some with both cholangio- and hepatocellular carcinomas) and 8 non-tumor-bearing brown bullheads were analyzed by 2D-PAGE. . Two isoforms of Apolipoproteins A-1 with a molecular weight of 28 kDA w...

42

HISTORICAL MONITORING OF BIOMARKERS OF PAH EXPOSURE OF BROWN BULLHEAD IN THE REMEDIATED BLACK RIVER AND THE CUYAHOGA RIVER, OHIO  

EPA Science Inventory

Biomarkers of exposure to chemical contamination were measured in brown bullhead from a heavily PAH contaminated section of the Black River, Ohio, during and immediately after remedial sediment dredging in 1990-1991, and in follow-up visits in 1993 and 1998. Biomarker levels of ...

43

Mitochondrial DNA diversity of brown bullhead from contaminated and relatively pristine sites in the Great Lakes  

SciTech Connect

Brown bullhead were sampled from contaminated and relatively pristine sites to determine whether there was any association between genetic diversity and site contamination. Nine sites were sampled in the lower Great Lakes: five from Areas of Concern (identified by the International Joint Commission as having significant environmental degradation) and four from relatively clean areas of similar habitat type. Genetic variation was surveyed in the mitochondrial genome using restriction fragment length polymorphisms. Sixteen restriction enzymes were used to identify 42 distinct mitochondrial DNA haplotypes among 163 fish. Eight pairwise comparisons of populations at contaminated vs. clean sites showed that genetic diversity estimates were always lower in populations from contaminated sites. The most parsimonious explanation is that reduced diversity is a result of stochastic reductions in population size that have culled much of the genetic diversity from populations. Although contaminated sites support large populations of brown bullhead, historical environmental degradation at these sites may have reduced population size in the past, resulting in reduced present-day genetic diversity.

Murdoch, M.H.; Hebert, P.D.N. (Univ. of Guelph, Ontario (Canada). Dept. of Zoology)

1994-08-01

44

Chlordane, DDT, PCB's, and other selected organic compounds in Asiatic clams and yellow bullhead in the Potomac River Basin, 1992  

USGS Publications Warehouse

Chlordane, DDT (dichlor-diphenyl-trichloroethane), and PCB's (polychlorinated biphenyls) were the most widespread organic contaminants detected during a 1992 survey of aquatic biological tissues in the Potomac River Basin. On the basis of existing U.S. Food and Drug Administration criteria, no new threats to human health were discovered, although chlordane concentrations may pose a threat to fish-eating wildlife. Chlordane exceeded the National Academy of Science and National Academy of Engineering recommended maximum concentration for the protection of fish-eating wildlife at two sites. The survey, conducted by the U.S. Geological Survey's National Water-Quality Assessment Program, sampled Asiatic clams (Corbicula fluminea) and yellow bullhead (Ameiurus natalis) at 16 sites to determine the occurrence and distribution of 29 hydrophobic organic compounds. Thirteen of these organic compounds were detected in the survey. Sites with the greatest number of compounds detected include the Potomac River near Alexandria, Va., with 6 compounds detected in Asiatic clam tissue, and Accotink Creek near Annandale, Va., with 11 compounds in yellow bullhead tissue. Chlordane was detected at six sites, with maximum concentrations of 31.1 ?g/kg (micrograms per kilograms) in Asiatic clam tissue and 127 ?g/kg in yellow bullhead whole-fish tissue. DDT was detected at five sites, with maximum concentrations of 12.9 ?g/kg in Asiatic clam tissue and 7.6 ?g/kg in yellow bullhead whole-fish tissue. PCB's were detected at nine sites, with maximum concentrations of 162 ?g/kg in Asiatic clam tissue and 146 mg/ kg in yellow bullhead whole-fish tissue.

Zappia, Humbert

1996-01-01

45

Az-Tech Medicine.  

ERIC Educational Resources Information Center

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…

Nicholson, Rob

2000-01-01

46

Patterns of {sup 137}Cs accumulation in bullhead catfish inhabiting an abandoned reactor reservoir  

SciTech Connect

The author assayed muscle {sup 137}Cs concentrations of bullhead catfish (Ameiurus natalis) in order to determine factors contributing to the bioconcentration of this fission product. Bullhead catfish (N = 173) were obtained from the Pond B reservoir, Savannah River Site, SC. Muscle {sup 137}Cs concentration did not differ between sexes (ANOVA, P = 0.631). Age of fish (1--6 yr) appeared to explain variation in {sup 137}Cs concentration (P = 0.005), but not when mass of fish was included as a model covariate (P = 0.086). Least-square means, adjusted for the covariate, suggested that 1 and 2 yr old fish (71.09 and 81.38 mean pCi/g, respectively) differed from 3, 4, 5, and 6 yr old fish (94.94, 92.34, 97.27, 90.25 mean pCi/g, respectively). Therefore, the effects of age and mass were evaluated by partitioning the data into young (1--2 yr) and older (3, 4, 5, and 6 yr) age classes. When adjusted for mass, age (young vs. old) significantly accounted for differences in {sup 137}Cs concentration (78.98 vs. 94.33 mean pCi/g; P = 0.005). Within older fish, neither age (P = 0.870) or mass (P = 0.361) significantly influenced {sup 137}Cs concentration. The effect of age within young fish was nonsignificant (P = 0.971) in contrast to the influence of mass (P = 0.044). This suggests that the contribution of `size` (mass) to {sup 137}Cs body burden is related to early growth and that these fish reach an asymptotic `steady-state` {sup 137}Cs concentration by 3 years of age.

McCreedy, C.D. [Purdue Univ., West Lafayette, IN (United States). Dept. of Veterinary Pathobiology; Jagoe, C.H.; Brisbin, L. Jr. [Savannah River Ecology Lab., Aiken, SC (United States)

1995-12-31

47

Use of molecular markers to study the effects of environmental impacts on genetic diversity in brown bullhead (Ameirus nebulosus) populations.  

PubMed

Conservation biology needs sound biological information in order to maintain biological diversity in the face of the current rate of loss. An important component of the information needed is the level of genetic diversity within and between populations, especially for those species faced with exposure to environmental stressors. We applied multilocus DNA profile analysis (highly variable number tandem repeats [HVNTR] and randomly amplified polymorphic DNA [RAPD] techniques) and allozyme analysis to test whether individuals from historically degraded sites display levels of genetic diversity different from individuals taken from reference sites. Four Lake Erie tributaries, two impacted and two reference sites, were the sources of brown bullhead (Ameiurus nebulosus) samples. Pairwise comparison of the sampled populations demonstrated an association of decreased genetic diversity with exposure of brown bullhead to stressors using both RAPD and HVNTR analysis. PMID:11699785

Silbiger, R N; Leonard, A C; Dimsoski, P; Foré, S; Guttman, S I; Roth, A C; Gordon, D A; Wessendarp, T; Toth, G P; Smith, M K

2001-11-01

48

Bioaccumulation of cesium-137 in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned nuclear reactor reservoir  

SciTech Connect

Bioaccumulation of {sup 137}Cs was investigated in yellow bullhead catfish (Ameiurus natalis) inhabiting an abandoned reactor reservoir, Pond B, Savannah River Site, Barnwell Co., South Carolina. The authors collected fish by trap-netting, and determined ages from pectoral spines. Muscle and other tissues were assayed for {sup 137}Cs by NaI-scintillation. Music {sup 137}Cs was unrelated to sex or mass of fish, but was related to age. Examination of least-squares means suggested that {sup 137}Cs in muscle increased up to about age 3, but did not increase with greater age. A modified Richards model showed equilibrium {sup 137}Cs concentration in muscle was acquired in approximately 2.4 years. Growth differed between sexes and the time to asymptotic body mass was longer than the time to attain equilibrium {sup 137}Cs concentration. Males attained an asymptotic mass of 577 g in approximately 6.3 years; females attained an asymptotic mass of 438 g in approximately 5.9 years. The cumulative {sup 137}Cs burden of the population was 4.9 {times} 10{sup 6} Bq, representing <0.001% of the {sup 137}Cs inventory of the reservoir. Concentration of {sup 137}Cs varied among tissues with gill and muscle the lowest and highest. Concentration of {sup 137}Cs in ovaries declined with increasing ovary mass. Until equilibrium is attained in these fish, {sup 137}Cs concentration is directly related to increasing age rather than size.

McCreedy, C.D.; Glickman, L.T. [Purdue Univ., West Lafayette, IN (United States). Dept. of Veterinary Pathobiology; Jagoe, C.H.; Brisbin, I.L. Jr. [Univ. of Georgia, Aiken, SC (United States). Savannah River Ecology Lab.

1997-02-01

49

Assessment of the fish tumor beneficial use impairment in brown bullhead (Ameiurus nebulosus) at selected Great Lakes Areas of Concern  

USGS Publications Warehouse

A total of 878 adult Brown Bullhead were collected at 11 sites within the Lake Erie and Lake Ontario drainages from 2011 to 2013. The sites included seven Areas of Concern (AOC; 670 individuals), one delisted AOC (50 individuals) and three non-AOC sites (158 individuals) used as reference sites. These fish were used to assess the “fish tumor or other deformities” beneficial use impairment. Fish were anesthetized, weighed, measured and any external abnormalities documented and removed. Abnormal orocutaneous and barbel tissue, as well as five to eight pieces of liver, were preserved for histopathological analyses. Otoliths were removed and used for age analyses. Visible external abnormalities included reddened (raised or eroded), melanistic areas and raised growths on lips, body surface, fins and barbels. Microscopically, these raised growths included papilloma, squamous cell carcinoma, osteoma and osteosarcoma. Proliferative lesions of the liver included bile duct hyperplasia, foci of cellular alteration, bile duct (cholangioma, cholangiocarcinoma) and hepatocellular (adenoma, hepatic cell carcinoma) neoplasia. The two reference sites (Long Point Inner Bay, Conneaut Creek), at which 30 or more bullhead were collected had a skin tumor prevalence of 10% or less and liver tumor prevalence of 4% or less. Presque Isle Bay, recently delisted, had a similar liver tumor prevalence (4%) and slightly higher prevalence (12%) of skin tumors. The prevalence of skin neoplasms was 15% or less at sites in the Black River, Cuyahoga River and Maumee AOCs, while more than 20% of the bullheads from the Rochester Embayment, Niagara River, Detroit River and Ashtabula River AOCs had skin tumors. The prevalence of liver tumors was greater than 4% at all AOC sites except the Old Channel site at the Cuyahoga River AOC, Wolf Creek within the Maumee AOC and the upper and lower sites within the Niagara River AOC.

Blazer, Vicki S.; Mazik, Patricia M.; Iwanowicz, Luke R.; Braham, Ryan P.; Hahn, Cassidy M.; Walsh, Heather L.; Sperry, Adam J.

2014-01-01

50

Characterization of the histone H2A.Z-1 and H2A.Z-2 isoforms in vertebrates  

E-print Network

of two H2A.Z protein isoforms in chicken that differ by 3Total H2A.Z protein was purified from chicken erythrocytesprotein isoforms (H2A.Z-1/H2A.Z-2) that was first determined by mass spectrometry in total H2A.Z isolated from chicken

2009-01-01

51

Pigmented macrophage aggregates as a biomarker of oxidative damage in yellow bullhead catfish, Ameiurus natalis  

SciTech Connect

Pigmented macrophage aggregates (PMs) occur when peroxidized lipids resulting from oxidative damage in tissues are scavenged by macrophages. Ionizing radiation causes oxidative damage, so the authors evaluated PMs as a biomarker in the pronephros of yellow bullheads (Ameiurus natalis) inhabiting Pond B, Savannah River Site, SC, a reservoir contaminated with low levels of {sup 137}Cs. ANOVA, ANCOVA, and stepwise regression were used to relate the mean number of PMs, per 0.15 mm{sup 2} of tissue section, to fish sex (females: N = 61; males: N = 84), age (1--6 yrs), body-condition, and muscle {sup 137}Cs concentration. Mean pronephric PMs differed by six and with fish muscle {sup 137}Cs concentration. Among males, PMs were positively correlated with fish age and {sup 137}Cs. In females, PMs were also correlated with fish age and {sup 137}Cs. ANCOVA, with age as covariate, affirmed that sex and muscle {sup 137}Cs were significantly associated with the mean number of pronephric PMs. Using stepwise regression, the interaction of age and {sup 137}Cs concentration was most strongly associated with pronephric PMs in males. Among females, the product of age, body-condition, and {sup 137}Cs concentration was most strongly associated with pronephric PMs. The positive relationships between the number of pronephric PMs and {sup 137}Cs concentration suggest that oxidative damage related to long-term exposure to low-level radiation is detectable in these fish. Secondarily, these results demonstrate the importance of considering covariates such as age and sex when evaluating effects of environmental contaminants.

McCreedy, C.D.; HoganEsch, H.; Turek, J. [Purdue Univ., W. Lafayette, IN (United States); Jagoe, C.H. [Savannah River Ecology Lab., Aiken, SC (United States)

1995-12-31

52

Multi-biomarker approach in wild European bullhead, Cottus sp., exposed to1 agricultural and urban environmental pressures: practical recommendations for2  

E-print Network

1 Multi-biomarker approach in wild European bullhead, Cottus sp., exposed to1 agricultural Risques (INERIS), UnitĂŠ8 d'Ecotoxicologie in vitro et in vivo, BP2, 60550 Verneuil-en-Halatte, France9 10-20Mar2014 Author manuscript, published in "Chemosphere 87, 7 (2012) 675-683" DOI : 10.1016/j

Paris-Sud XI, UniversitĂŠ de

53

Waste Toolkit A-Z Plastic Grundon  

E-print Network

Waste Toolkit A-Z Plastic ­ Grundon Also see `Swap Shop' and `Office Recycling ­ Grundon' in the Waste Toolkit A-Z How can I recycle plastic? There are lots of different types of plastic. Typically, waste contractors can only recycle PETE plastic and HDPE plastic. The University's preferred waste

Melham, Tom

54

Waste Toolkit A-Z Garden waste  

E-print Network

Waste Toolkit A-Z Garden waste Also see `Plant Swap' in the Waste Toolkit A-Z How can I recycle garden waste from my department? Typically, the University Parks Department collects and recycles the departments' green garden waste. The Parks Department takes the garden waste (grass, leaves and other plant

Melham, Tom

55

33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...  

Code of Federal Regulations, 2013 CFR

...W; along the shoreline to 35°01?05? N, 114°38?20? W. 2. Rockets Over the River Sponsor Laughlin Tourism Committee. Event Description Fireworks Display Date First week in July. Location Laughlin, NV....

2013-07-01

56

33 CFR 165.1124 - Annual Firework Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and...  

Code of Federal Regulations, 2012 CFR

...W; along the shoreline to 35°01?05? N, 114°38?20? W. 2. Rockets Over the River Sponsor Laughlin Tourism Committee. Event Description Fireworks Display Date First week in July. Location Laughlin, NV....

2012-07-01

57

33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...  

Code of Federal Regulations, 2011 CFR

...Colorado River at Laughlin, Nevada, from the Pioneer Hotel to the Edgewater Hotel. Laughlin Aquamoto Sports Challenge and Expo ...near Laughlin, Nevada, from Davis Dam to Harrah's Hotel and Casino. Parker Thanksgiving Regatta...

2011-07-01

58

33 CFR 100.1102 - Marine Events on the Colorado River, between Davis Dam (Bullhead City, Arizona) and Headgate Dam...  

Code of Federal Regulations, 2010 CFR

...Colorado River at Laughlin, Nevada, from the Pioneer Hotel to the Edgewater Hotel. Laughlin Aquamoto Sports Challenge and Expo ...near Laughlin, Nevada, from Davis Dam to Harrah's Hotel and Casino. Parker Thanksgiving Regatta...

2010-07-01

59

Characterization of the histone H2A.Z-1 and H2A.Z-2 isoforms in vertebrates  

Microsoft Academic Search

BACKGROUND: Within chromatin, the histone variant H2A.Z plays a role in many diverse nuclear processes including transcription, preventing the spread of heterochromatin and epigenetic transcriptional memory. The molecular mechanisms of how H2A.Z mediates its effects are not entirely understood. However, it is now known that H2A.Z has two protein isoforms in vertebrates, H2A.Z-1 and H2A.Z-2, which are encoded by separate

Deanna Dryhurst; Toyotaka Ishibashi; Kristie L Rose; José M Eirín-López; Darin McDonald; Begonia Silva-Moreno; Nik Veldhoen; Caren C Helbing; Michael J Hendzel; Jeffrey Shabanowitz; Donald F Hunt; Juan Ausió

2009-01-01

60

Assessing the ecosystem service potential of Tucson AZ's urban forest  

NASA Astrophysics Data System (ADS)

Urbanization is arguably one of the most dramatic forms of landscape change, and an important anthropogenic influence on the structure and function of ecosystems. Cities have obvious impacts on local ecologies and environments, such as shifts in species diversity and alteration of local microclimates. While scientists are now familiar with many of these localized impacts of urbanization, cities and suburban areas contribute to 10-15 % of surface land cover in the conterminous U.S., pointing to the potential, yet poorly understood, contribution of cities to regional, national, and global carbon (C) and energy budgets. As cities continue to expand urban ecologists place more emphasis on understanding the functions of urban ecosystems and the ecosystem services (e.g. habitat, air, and water quality) that cities provide. While studies demonstrate that the urban environment alters the structure and function of remnant patches of native ecosystems relative to their non-urban counterparts, the ability of restoration, planning, and design to improve the provision of ecosystem services is a new approach within ecology. One strategy involves green urban design, or using ecological principles for planning or reinvigorating certain ecological processes, in cities. Increasing the amount of vegetative cover can reduce this effect by reinforcing ecosystem services in cities, including shading of surfaces, promotion of cooling through evapotranspiration, and the sequestration of atmospheric CO2 in plant tissues and soils. However, the on-the-ground reality of such strategies is relatively unknown. A pilot study is being conducted in Tucson, AZ to investigate the impact of increasing the cover of trees in the urban landscape on local microclimates and the urban heat island. Trees (Velvet Mesquite, Chilean Mesquite, and Desert Willow) were planted in two neighborhoods in Tucson in 1990. We are collecting data during the summer 2011 monsoon (DBH, crown volume, and hemispherical canopy photos) to asses growth of the trees in the urban environment. These growth rates, and associated ecosystem services (C-sequestration, energy savings, pollution mitigation, etc.) are evaluated using US Forest Service models (Tree Carbon Calculator and i-tree software) to determine how the performance of trees in the Tucson urban environment perform vs. model predictions. We hypothesize that the models overestimate tree performance as Tucson differs in water availability relative to the cities the model was parameterized in (e.g. Glendale), both in terms of soil water holding capacities and also city "water culture." This preliminary study will provide a data collection framework for a citizen science urban forestry project which will provide data to improve environmental decision making related to the interaction of plants, water, and energy balance in this arid city.

Pavao-Zuckerman, M.

2011-12-01

61

77 FR 19927 - Amendment of Class E Airspace; Willcox, AZ, and Revocation of Class E Airspace; Cochise, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...Airport, Willcox, AZ. Controlled airspace is necessary to accommodate aircraft using Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at Cochise County Airport, Willcox, AZ. Decommissioning...

2012-04-03

62

Applications in environmental risk assessment of leucocyte apoptosis, necrosis and respiratory burst analysis on the European bullhead, Cottus sp.  

PubMed

The use of a biochemical multi-biomarker approach proved insufficient to obtain clear information about ecosystem health. The fish immune system is considered as an attractive non-specific marker for environmental biomonitoring which has direct implications in individual fitness and population growth. Thus, the present work proposes the use of fish immunomarkers together with more common biochemical biomarkers in sampling conditions optimized to reduce biomarker variability and increase parameter robustness. European bullheads (Cottus sp.) from 11 stations in the Artois-Picardie watershed (France) were sampled. In the multiple discriminant analysis, the sites were highly correlated with apoptosis, respiratory burst, GST and EROD activities. Moreover, the use together of biochemical and immune markers increased the percentage of fish correctly classed at each site and enhanced site separation. This study argues in favor of the utilization of apoptosis, necrosis and respiratory burst for the determination of environmental risk assessment in addition to the set of biochemical biomarkers commonly used in fish. PMID:24012786

Bado-Nilles, Anne; Jolly, Sabrina; Porcher, Jean-Marc; Palluel, Olivier; Geffard, Alain; Gagnaire, Béatrice; Betoulle, Stéphane; Sanchez, Wilfried

2014-01-01

63

Waste Toolkit A-Z Wooden Pallets  

E-print Network

Waste Toolkit A-Z Wooden Pallets Can I recycle wooden pallets? Yes.Departments and colleges can recycle wooden pallets through a local company called TR Recycling. TR Recycling provides bulky waste Plastics (non-contaminated plastic only ­ contact TR Recycling for details) Soil & green waste Wooden

Melham, Tom

64

February 2014AZ1617 What is diabetes?  

E-print Network

February 2014AZ1617 What is diabetes? Diabetes is a disease that your blood glucose, also called get into the cells of your body for energy. People with diabetes don't make enough insulin or the body cells do not respond to insulin, causing glucose to build up in the blood. (See Figure: Diabetes

Sanderson, Mike

65

Waste Toolkit A-Z Plastic bags  

E-print Network

plastic bags in the University recycling. Instead, choose alternatives to plastic bags when shoppingWaste Toolkit A-Z Plastic bags Can I recycle plastic bags? No. At the moment you can't recycle have to use a cotton bag 131 times to ensure it has lower global warming potential than a plastic

Melham, Tom

66

Waste Toolkit A-Z Mobile phones  

E-print Network

Waste Toolkit A-Z Mobile phones How to recycle your mobile phone Recycling your mobile phone makes and recycling can help to reduce the demand for new raw materials. Do not put mobile phones in the recycling waste company Most mobile phone shops recycle old mobiles, so you can either take your old mobile

Melham, Tom

67

Biochemistry Games: "AZ-Quiz" and "Jeopardy!"  

ERIC Educational Resources Information Center

"AZ-Quiz" and "Jeopardy!" are popular television shows and serve as the basis for in-class games designed to support and diversify chemistry instruction at the high school level. Both games were created in Microsoft PowerPoint, which is an easily accessible and controllable instrument that enables the creation of engaging animation. The use of…

Rostejnska, Milada; Klimova, Helena

2011-01-01

68

Neighborhood socioeconomic status is a useful predictor of perennial landscape vegetation in residential neighborhoods and embedded small parks of Phoenix, AZ  

Microsoft Academic Search

Though landscape vegetation in cities is human-mediated and often more diverse than that in surrounding environments, little work has been done to quantify ways that humans shape its composition. Our study identified important sources of variation in perennial vegetation composition within residential neighborhoods of Phoenix, AZ, USA. We hypothesized that neighborhood socioeconomic status (SES) should offer some capacity for predicting

Chris A. Martin; Paige S. Warren; Ann P. Kinzig

2004-01-01

69

Tank 241-AZ-101 and Tank 241-AZ-102 Airlift Circulator Operation Vapor Sampling and Analysis Plan  

Microsoft Academic Search

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of the tank 241-AZ-101 and 241-AZ-102 airlift circulators (ALCs) and during the initial operation (''bump'') of the tank 241-AZ-101 mixer pumps. The purpose of the ALC operation is to support portions of the operational

1999-01-01

70

15. View to the northwest along railroad tracks. AZ180 (Arizona ...  

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

15. View to the northwest along railroad tracks. AZ-180 (Arizona and New Mexico Railroad Passenger Depot) at left. In the background can be seen, left to right, AZ-178 (Arizona Copper Company Office), AZ-177 (Arizona Copper Company Library Hall), AZ-179 (Park Avenue Bridge) and AZ-183 (La Casa Grande). - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

71

702AZ aging waste ventilation facility year 2000 test procedure  

SciTech Connect

This test procedure was developed to determine if the 702AZ Tank Ventilation Facility system is Year 2000 Compliant. The procedure provides detailed instructions for performing the operations necessary and documenting the results. This verification procedure will document that the 702AZ Facility Systems are year 2000 compliant and will correctly meet the criteria established in this procedure.

Winkelman, W.D.

1998-07-22

72

Antizyme (AZ) regulates intestinal cell growth independent of polyamines.  

PubMed

Since antizyme (AZ) is known to inhibit cell proliferation and to increase apoptosis, the question arises as to whether these effects occur independently of polyamines. Intestinal epithelial cells (IEC-6) were grown in control medium and medium containing 5 mM difluoromethylornithine (DFMO) to inhibit ODC, DFMO + 5 ľM spermidine (SPD), DFMO + 5 ľM spermine (SPM), or DFMO + 10 ľM putrescine (PUT) for 4 days and various parameters of growth were measured along with AZ levels. Cell counts were significantly decreased and mean doubling times were significantly increased by DFMO. Putrescine restored growth in the presence of DFMO. However, both SPD and SPM when added with DFMO caused a much greater inhibition of growth than did DFMO alone, and both of these polyamines caused a dramatic increase in AZ. The addition of SPD or SPM to media containing DFMO + PUT significantly inhibited growth and caused a significant increase in AZ. IEC-6 cells transfected with AZ-siRNA grew more than twice as rapidly as either control cells or those incubated with DFMO, indicating that removal of AZ increases growth in cells in which polyamine synthesis is inhibited as well as in control cells. In a separate experiment, the addition of SPD increased AZ levels and inhibited growth of cells incubated with DFMO by 50%. The addition of 10 mM asparagine (ASN) prevented the increase in AZ and restored growth to control levels. These results show that cell growth in the presence or absence of ODC activity and in the presence or absence of polyamines depends only on the levels of AZ. Therefore, the effects of AZ on cell growth are independent of polyamines. PMID:24930035

Ray, Ramesh M; Bhattacharya, Sujoy; Bavaria, Mitul N; Viar, Mary Jane; Johnson, Leonard R

2014-09-01

73

Benzo(a)pyrene exposure causes adaptive changes in p53 and CYP1A gene expression in Brown bullhead (Ameiurus nebulosus).  

PubMed

The Brown bullhead (Ameiurus nebulosus) is able to survive and reproduce in high levels of environmentally contaminated areas of the Great Lakes. The purpose of this study was to establish whether there are adaptive genetic/molecular changes occurring in these fish that allow for their survival. Expression of a cell cycle regulator, p53 and the toxin metabolizing protein, CYP1A were measured in liver tissue from bullhead caught from either clean or contaminated areas of Lake Erie and surrounding areas. Wild caught fish and F1 raised offspring (whose parents originated from clean and contaminated sites) were used to measure endogenous gene expression levels. Results revealed that endogenous expression of p53 was on average 6.6× higher in contaminated fish than in fish caught from clean sites. Interestingly, when fed benzo(a)pyrene (BaP)-treated food, p53 expression increased 0.2× in clean fish and decreased 2.6× in contaminated fish. Endogenous CYP1A expression was not detectable in clean fish and low in contaminated fish. Upon exposure to BaP-treated food, CYP1A expression increased in both clean and contaminated fish, although at a higher rate in clean fish. Furthermore, when fish were cleared and then re-exposed to BaP, CYP1A expression increased from basal levels at a higher rate in clean versus contaminated fish. CYP1A and p53 expression in F1 offspring was similar to wild caught fish at the endogenous level and when fed BaP treated food. Results suggest that fish in contaminated regions may be implementing an adaptive response to severe environmental stress by maintaining high expression of p53 and low expression of CYP1A; thus lending increased protection to cells and decreasing the potential amount of carcinogens produced by contaminant metabolism. PMID:25259779

Williams, R; Hubberstey, A V

2014-11-01

74

Application of yttrium in AZ61 magnesium alloy and the semi-solid AZ61 alloy  

Microsoft Academic Search

The semi-solid magnesium alloy slurry was prepared by a newly self-developed mechanical stirring machine for preparing continuous semi-solid slurry, the effects of rare earth elements yttrium on the ignition point, the casting microstructure, the semi-solid microstructure and mechanical properties of AZ61 magnesium alloy were studied in this paper. The experimental results showed that increasing the Y content would increase the

Zhou Bingfeng; Yan Hong

2010-01-01

75

Recycle City  

NSDL National Science Digital Library

Recycle City contains an interactive city map that demonstrates how residents of every section of the city, formerly Dumptown, have recycled, reduced, and reused waste to turn their town around. There is a Dumptown Game with a Control Center to monitor displays while Dumptown changes as waste reduction programs are put in place. Students can create their own Recycle City scavenger hunt or go to the Activities area and see other ways to put Recycle City to use to help protect the environment.

1997-01-01

76

Tank 241-AZ-101 and Tank 241-AZ-102 Airlift Circulator Operation Vapor Sampling and Analysis Plan  

SciTech Connect

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of the tank 241-AZ-101 and 241-AZ-102 airlift circulators (ALCs) and during the initial operation (''bump'') of the tank 241-AZ-101 mixer pumps. The purpose of the ALC operation is to support portions of the operational test procedure (OTP) for Project W-030 (OTP-W030-001) and to perform functional test in support of Project W-151. Project W-030 is the 241-A-702 ventilation upgrade project (241-142-702) and Project W-151 is the 241-AZ-101 Mixer Pump Test. The functional tests will check the operability of the tank 241-AZ-101 ALCs. Process Memo's No. 2E98-082 and No. 2E99-001 (LMHC 1999a, LMHC 1999b) direct the operation of the ALCs and the Industrial Hygiene monitoring respectively. A series of tests will be conducted in which the ALCs in tanks 241-AZ-101 and 241-AZ-102 will be operated at different air flow rates. Vapor samples will be obtained to determine constituents that may be present in the tank headspace during ALC operation at tanks 241-AZ-101 and 241-AZ-102 as the waste is disturbed. During the testing, vapor samples will be obtained from the headspace of tanks 241-AZ-101 and 241-AZ-102 via the unused port on the standard hydrogen monitoring system (SHMS). In addition the last two vapor samples will be collected from the headspace of tank 241-AZ-101 during the operation of the mixer pumps. Each mixer pump will be operated for approximately 5 minutes. Results will be used to provide the waste feed delivery program with environmental air permitting data for tank waste disturbing activities. Because of radiological concerns, the samples will be filtered for particulates. It is recognized that this may remove some organic compounds. The following sections provide the general methodology and procedures to be used in the preparation, retrieval, transport, analysis, and reporting of results from vapor samples retrieved during the ALC testing.

TEMPLETON, A.M.

1999-12-07

77

78 FR 3877 - Radio Broadcasting Services; Peach Springs, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...MB Docket No. 12-374; RM-11687; DA 12-2072] Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal...415 and 1.420. List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. Federal Communications Commission....

2013-01-17

78

Tank 241-AZ-101 and tank 241-AZ-102, airlift circulator operation vapor sampling and analysis plan  

Microsoft Academic Search

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of the tank 241-AZ-101 and 241-AZ-102 airlift circulators (ALCs). The purpose of the ALC operation is to support portions of the operational test procedure (OTP) for Project W-030 (OTP-W030-001) and to perform functional test

1999-01-01

79

241-AZ-101 pump removal trough analysis  

SciTech Connect

As part of the current Hanford mission of environmental cleanup, various long length equipment must be removed from highly radioactive waste tanks. The removal of equipment will utilize portions of the Equipment Removal System for Project W320 (ERS-W320), specifically the 50 ton hydraulic trailer system. Because the ERS-W320 system was designed to accommodate much heavier equipment it is adequate to support the dead weight of the trough, carriage and related equipment for 241AZ101 pump removal project. However, the ERS-W320 components when combined with the trough and its` related components must also be analyzed for overturning due to wind loads. Two troughs were designed, one for the 20 in. diameter carriage and one for the 36 in. diameter carriage. A proposed 52 in. trough was not designed and, therefore is not included in this document. In order to fit in the ERS-W320 strongback the troughs were design with the same widths. Structurally, the only difference between the two troughs is that more material was removed from the stiffener plates on the 36 in trough. The reduction in stiffener plate material reduces the allowable load. Therefore, only the 36 in. trough was analyzed.

Coverdell, B.L.

1995-10-17

80

Cities Guide  

NSDL National Science Digital Library

From The Economist, their Cities Guide offers practical information ranging from accommodations to insider tips on getting around various US and world cities. A very nice touch are areas like the City Briefing section (top news stories, history pieces, and other tidbits) and the Being There area (subtopics include how to kill an hour and gifts to take home). City Guide also contains sections on cultural events, shopping, history, facts, and much more. [REB].

2001-01-01

81

Tensile city  

E-print Network

Tensile City is a story that provides the answer to the following question: II If we were to leap forward in time and visit a city of the future, what would learn about our contemporary city ? II The story unfolds when ...

Chakkour, Mario Henri

1987-01-01

82

Historic Cities  

NSDL National Science Digital Library

Jointly sponsored by the Historic Cities Center within the Department of Geography at Hebrew University and the Jewish National and University Library, the Historic Cities Web site is intended to contain maps, literature, documents, books, and other relevant material concerning the past, present, and future of historic cities While some of these documents and ephemera are still forthcoming to the site, visitors will find a wide array of historic city maps and views dating from 1486 to 1720. The scanned maps are searchable alphabetically, by date, and by individual cartographer. Additionally, a bit of information is provided about each cartographer. Overall, the site contains close to two hundred individual city maps and renderings, ranging from medieval Heidelberg to Casablanca. For persons with an interest in urban morphology and the history of cartography, the Historic Cities site will be a good place to start.

83

City Mayors  

NSDL National Science Digital Library

Drawing on the expertise of a team of editors who reside in Britain, Germany, Spain, Mexico, France, and a number of other countries, the City Mayors organization is an "international network of professionals working to promote strong cities and good local government." Their website takes on all of the important urban issues of the day, including governance, affordable housing, sustainable development, transportation, and a number of other pressing issues. On their homepage, visitors will find links to recent news stories from cities around the world and direct links to thematic sections such as business, finance, environment, and development. One section that should not be missed is the "City Rankings" area, which includes helpful lists of the largest cities in the world by land area, population and density, along with a list of the most expensive cities in the world.

84

The evolutionary differentiation of two histone H2A.Z variants in chordates (H2A.Z-1 and H2A.Z-2) is mediated by a stepwise mutation process that affects three amino acid residues  

Microsoft Academic Search

BACKGROUND: The histone H2A family encompasses the greatest number of core histone variants of which the replacement variant H2A.Z is currently one of the most heavily studied. No clear mechanism for the functional variability that H2A.Z imparts to chromatin has yet been proposed. While most of the past studies have referred to H2A.Z generically as a single protein, in vertebrates

José M Eirín-López; Rodrigo González-Romero; Deanna Dryhurst; Toyotaka Ishibashi; Juan Ausió

2009-01-01

85

Great Zoom into the Grand Canyon, AZ  

NSDL National Science Digital Library

Using data from different spacecraft and some powerful computer technology, visualizers at the Goddard Space Flight Center present you with a collection of American cities in a way you have never seen them before. Starting with our camera high above the Earth, we rush in towards the surface at what would be an impossible speed for any known vehicle. Passing though layers of atmosphere, the colors of our destinations shimmer with their own unique characteristics, and suddenly we find ourselves floating in virtual space just above the ground.

Greg Shirah

2003-01-14

86

19. View to the north of Riverside Avenue. AZ196(J. C. ...  

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

19. View to the north of Riverside Avenue. AZ-196(J. C. Gatti House) at left Part of AZ-197 (Shannon Copper Company Store) can be seen in group of buildings at right - Clifton Townsite, Confluence of Chase Creek & San Francisco River, Clifton, Greenlee County, AZ

87

Deposition of Histone Variant H2A.Z within Gene Bodies Regulates Responsive Genes  

E-print Network

DNA. RNA sequencing and genomic mapping of H2A.Z show that H2A.Z enrichment across gene bodies, ratherDeposition of Histone Variant H2A.Z within Gene Bodies Regulates Responsive Genes Devin Coleman at the transcriptional start sites of genes, has been implicated in a variety of chromosomal processes. Recently, we

88

Mexico City  

Atmospheric Science Data Center

... Mexico City has one of the world's most serious air pollution problems. The city is located atop a high plain at an altitude of ... as the orange and red areas, and mountainous areas appear light blue and green. The position of the clouds within the 70-degree image are ...

2013-04-18

89

Waste Toolkit A-Z Plastic cups Grundon  

E-print Network

Waste Toolkit A-Z Plastic cups ­ Grundon Can I recycle plastic cups? Yes, you can recycle plastic be recycled in the Grundon recycling box and must go in the landfill waste bin. PET Polyethylene Terepthalate Density Polyethylene X Othere All other resins and multi-materials X Can I reduce plastic cup waste? It

Melham, Tom

90

Corrosion resistance of titanium ion implanted AZ91 magnesium alloy  

Microsoft Academic Search

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

Liu Chenglong; Xin Yunchang; Tian Xiubo; J. Zhao; Paul K. Chu

2007-01-01

91

75 FR 76293 - Radio Broadcasting Services; Peach Springs, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...DA 10-2212; MB Docket No. 09-204; RM-11580] Radio Broadcasting Services; Peach Springs, AZ AGENCY: Federal...a)(1)(A). List of Subjects in 47 CFR Part 73 Radio, Radio broadcasting. 0 As stated in the preamble, the...

2010-12-08

92

75 FR 22697 - Safety Zone; APBA National Tour, Parker, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...1625-AA00 Safety Zone; APBA National Tour, Parker, AZ AGENCY: Coast Guard, DHS. ACTION...navigable waters of the Colorado River in Parker, Arizona for the APBA National Tour...APBA National Tour, which is held in Parker, Arizona. This temporary safety...

2010-04-30

93

78 FR 19988 - Safety Zone; BWRC Spring Classic, Parker, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...1625-AA00 Safety Zone; BWRC Spring Classic, Parker, AZ AGENCY: Coast Guard, DHS. ACTION...navigable waters of the Colorado River in Parker, Arizona for the Blue Water Resort and...Moovalya region of the Colorado River in Parker, Arizona. This temporary safety...

2013-04-03

94

nature.com Publications A-Z index  

E-print Network

nature.com Publications A-Z index Browse by subject My account Submit manuscript Register.comjournal homeadvance online publicationArticlefull text Previous articleNext article Nature Photonics | Article Science jobs from naturejobs Developer r Nature Publishing Group r London, UK Post a free job More

Liu, Taosheng

95

Mixer pump test plan for double shell tank AZ-101  

SciTech Connect

Mixer pump systems have been chosen as the method for retrieval of tank wastes contained in double shell tanks at Hanford. This document describes the plan for testing and demonstrating the ability of two 300 hp mixer pumps to mobilize waste in tank AZ-101. The mixer pumps, equipment and instrumentation to monitor the test were installed by Project W-151.

STAEHR, T.W.

1999-05-12

96

User Manual for the AZ-101 Data Acquisition System (AS-101 DAS)  

SciTech Connect

User manual for the TK AZ-101 Waste Retrieval System Data Acquisition System. The purpose of this document is to describe use of the AZ-101 Data Acquisition System (AZ-101 DAS). The AZ-101 DAS is provided to fulfill the requirements for data collection and monitoring as defined in Letters of Instruction (LOI) from Numatec Hanford Corporation (NHC) to Fluor Federal Services (FFS). For a complete description of the system, including design, please refer to the AZ-101 DAS System Description document, RPP-5572.

BRAYTON, D.D.

2000-02-17

97

8-Hydroxy-2{prime}-deoxyguanosine (8-OH-dG): A biomarker of oxidative damage in yellow bullheads chronically exposed to low-level radiation  

SciTech Connect

8-hydroxy-2{prime}-deoxyguanosine (8-OH-dG), an oxidation product of the nucleotide deoxyguanosine (dG) was used as a biomarker to assess oxidative damage in brain and gill tissues of yellow bullhead catfish (Ameiurus natalis; n = 18) inhabiting an abandoned reactor reservoir contaminated with low levels of {sup d137}Cs (Pond B, Savannah River Site, SC). DNA was isolated by chloroform-isoamyl extraction, enzymatically digested with Nuclease P1/Calf Intestinal Phosphatase, and analyzed by HPLC with electrochemical detection.Length, weight, age, condition and muscle {sup 137}Cs activity of each fish were also determined. Concentrations of 8-OH-dG were greater in brain than in gill tissues. 8-OH-dG in gill tissues decreased as condition of fish increased, but as age increased, the effect of condition declined. Brain 8-OH-dG concentration was not related to age or condition of fish, but was greater in females and the interaction between gender and {sup 137}Cs was significant. Brain 8-OH-dG was positively associated with muscle {sup 137}Cs concentration among females, but was unrelated to {sup 137}Cs concentration in males. At lower {sup 137}Cs concentrations, females tended to have fewer oxidative DNA adducts in brian than did males. Deposition of somatic lipids into eggs may provide females some anti-oxidant benefit by diminishing the contribution of lipid peroxidation to DNA damage. 8-OH-dG is a sensitive biomarker of low-level radiation exposure, however, its application in fish requires consideration of factors such as gender, age, body-condition, and the tissue type sampled.

McCreedy, C.D.; Glickman, L.T. [Purdue Univ., W. Lafayette, IN (United States). Dept. of Veterinary Pathobiology; Jagoe, C.H. [Savannah River Ecology Lab., Aiken, SC (United States)

1995-12-31

98

Recycle City  

NSDL National Science Digital Library

Recycling made fun. The Environmental Protection Agency's Recycle City Web site offers students an interactive way to learn how recycling can affect their environment. Users can click any part of the cartoon drawing of the city to learn about that particular building or site and what can be done to decrease waste. The site also contains a more involved exercise called the Dumptown game, where visitors click on City Hall to view various recycling programs and choose the program(s) the city will implement. Once implemented, that activity can be seen taking place in Dumptown. Although the Dumptown exercise may require the help of a teacher to navigate for younger students, both exercises are excellent for K-12 teachers and students.

99

Virtual City  

NSDL National Science Digital Library

In conjunction with Rice Design Alliance's Virtual City lecture series held earlier this year, home pages have been put up for two of the speakers, Howard Rheingold and Bruce Sterling, with access to online writings included.

1994-01-01

100

Open City  

NSDL National Science Digital Library

Are you interested in improving civic culture and knowledge with apps? If so, you will be delighted to learn about the Open City site. The Open City folks are a group of programmers, citizen activists, and policy types that create apps with open data in order "to improve transparency and understanding of our government." Chicagoans can stop by the Merchandise Mart to meet up and work with Open City in person. Everyone else can check out the Projects page to view apps like "Chicago Councilmatic," "How's Business?" and "Crime in Chicago." Each of these apps takes open source data from the city of Chicago and other organizations to create tools designed to help decision makers, journalists, and scholars with their various projects. The site also contains information about the people behind the organization and press releases about their work.

101

Vatican City.  

PubMed

Vatican City, the administrative and spiritual capital of the Roman catholic Church, has a population of 1000. Citizenship is generally accorded only to those who reside in Vatican City for reasons of office of employment. Supreme legislative, executive, and judicial power is currentily exercised by Pope John Paul II, the 1st non-italian pope in 5 centuries. The State of Vatican City is recognized by many nations as an independent sovereign state under the temporal jurisdiction of the Pope. By 1984, 108 countries had established diplomatic relations with the Holy See, most of which are not Roman Catholic. Third World countries comprise a large proportion of countries that have recently established relations with the Holy See. The US re-established relations with the Vatican in 1984 and there is frequent contact and consultation between the 2 states on key international issues. PMID:12178097

1984-11-01

102

XPS study of the surface chemistry on AZ31 and AZ91 magnesium alloys in dilute NaCl solution  

NASA Astrophysics Data System (ADS)

The surface chemistry on AZ31 and AZ91 magnesium alloys was characterized by X-ray photoelectron spectroscopy (XPS) in the corrosion and the passivation zones. In the corrosion zone, the presence of Mg(OH) 2 and MgCO 3 species was found in the outer surface, whereas, in the inner layer, the co-existence of Mg(OH) 2, MgO and MgCO 3 species was observed for both alloys. The presence of Al 3+ in the surface electrolyte to form Al 2O 3/Al(OH) 3 and the formation of carbonate product provide a better passivation on the surfaces and retard the chloride-induced corrosion on the materials in the passivation zone.

Wang, Lei; Shinohara, Tadashi; Zhang, Bo-Ping

2010-08-01

103

City 2020+  

NASA Astrophysics Data System (ADS)

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 temŹperatures 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 several public transport units running all across the city. This is accompanied by an analysis of probability density functions (PDF) for heat waves based on recent climate data and climate projections. A dense net of 40 PM measurement sites is operated in order to obtain the spatial pattern of PM concentration as depending on meteorological condition and location. It is lined out how this climate related sub-projects interact with investigations on social networks, governance issues, buildings structure development and health outcome. Related to the later the chemical composition of PM is analyzed in more detail and related to the spatial patterns of health deficiencies. At a later stage City2020+ will propose new strategies based on cooperation from the fields of medicine, geography, sociology, history, civil engineering, and architecture for adapting the city for future needs. The Project CITY 2020+ is part of the interdisciplinary Project House HumTec (Human Sciences and Technology) at RWTH Aachen University funded by the Excellence Initiative of the German federal and state governments through the Deutsche Forschungsgemeinschaft (German Research Foundation, DFG).

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

2010-09-01

104

Thixotropic deformation behavior of semi-solid AZ61 magnesium alloy during compression process  

Microsoft Academic Search

Compression tests on semi-solid AZ61 magnesium alloy fabricated by strain-induced melt activation (SIMA) and the conventional as-casted were carried out using the Gleeble-1500 dynamic material testing machine. The relationships between stress and strain and the microstructural evolutions for AZ61 magnesium alloy were analyzed in different deformation conditions. The results show that the deformation resistance of semi-solid AZ61 magnesium alloy is

Hong Yan; Bingfen Zhou

2006-01-01

105

Influence of microstructure on the corrosion of diecast AZ91D  

Microsoft Academic Search

The corrosion of die cast AZ91D was studied and related to its microstructure. For comparison and to more fully understand the behaviour of die cast AZ91D, corrosion studies and microstructural examinations were also carried out using slowly solidified high purity AZ91, Mg-2%Al, Mg-9%Al, low purity magnesium and high purity magnesium. Corrosion was studied in 1 N NaCl at pH 11

Guangling Song; Andrej Atrens; Matthew Dargusch

1998-01-01

106

The Cities.  

ERIC Educational Resources Information Center

Over the past two decades, direct payments from the Federal Government to local governments has increased more than sixfold as a percentage of the revenues local governments raise on their own. Both the Ford budget and the Carter budget revisions for 1977 and 1978 contain policy changes with important implications for cities. In this document…

Nathan, Richard P.; Dommel, Paul R.

107

78 FR 7391 - Motorized Travel Management Plan, Tonto National Forest; Gila, Maricopa, Pinal, and Counties, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...DEPARTMENT OF AGRICULTURE Forest Service Motorized Travel Management Plan, Tonto National Forest; Gila, Maricopa, Pinal, and Counties, AZ AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare...

2013-02-01

108

241-AZ Tank Farm Construction Extent of Condition Review for Tank Integrity  

SciTech Connect

This report provides the results of an extent of condition construction history review for tanks 241-AZ-101 and 241-AZ-102. The construction history of the 241-AZ tank farm has been reviewed to identify issues similar to those experienced during tank AY-102 construction. Those issues and others impacting integrity are discussed based on information found in available construction records, using tank AY-102 as the comparison benchmark. In the 241-AZ tank farm, the second DST farm constructed, both refractory quality and tank and liner fabrication were improved.

Barnes, Travis J.; Boomer, Kayle D.; Gunter, Jason R.; Venetz, Theodore J.

2013-07-30

109

Criminal Victimization And Perceptions Of Community Safety In 12 Cities, 1998  

NSDL National Science Digital Library

This report, recently released by the Bureau of Justice Statistics, provides city-level survey data on crime victimization in twelve US cities: Chicago, IL; Kansas City, MO; Knoxville, TN; Los Angeles, CA; Madison, WI; New York, NY; San Diego, CA; Savannah, GA; Spokane, WA; Springfield, MA; Tucson, AZ; and Washington, DC. The report presents data on community policing, the rates at which residents are victimized by crime, citizens' perceptions of crimes and their attitudes toward their community and local law enforcement agencies. The report is available in .pdf or ASCII format. Users may also download a compressed file (.zip) containing all the survey data spreadsheets (.wk1).

110

Air composition over Siberian cities.  

NASA Astrophysics Data System (ADS)

It is typical feature of Siberian cities that the quality of the atmosphere significantly depends on the climate conditions. During more than half of year, stable atmospheric stratification dominates over Siberia with temperature inversions, favoring accumulation of pollutants of different origin in the lower atmospheric layers. In addition to severe climatic conditions, modern industrial cities experience increasingly intensifying effect of anthropogenic factors on the environment and human health. Urban conditions give rise to distinct mesoclimates favoring accumulation of pollutants. In this case, natural and anthropogenic systems (power-generating and industrial objects, traffic, etc.) interact very closely. In this paper we present experimental results of the study the local air circulation effect on air composition of industrial cities of Siberian region. In our studies we have used AKV-2 mobile station, designed at the Institute of Atmospheric Optics SB RAS. The instrumentation of the station provides measurements of air temperature and humidity, wind speed and direction, total solar radiation; aerosol number density in two size ranges (0.4-10 microns by use of a modernized AZ-6 optical particle counter, and from 3 to 200 nm with a diffusion spectrometer of aerosols), and concentration of trace gases (NO, NO2, O3, SO2, CO, CO2). In addition to the continuous observations during the station motion, in Angarsk, Usol'e-Sibirskoe, Tulun, Nizhneudinsk, Taishet, Kansk, Krasnoyarsk, and Achinsk, we have carried measurements during stops at the city entry, near center, and at the exit. These observations were aimed to estimate the contribution of urban circulation to impurity accumulation on the city territory and to the change of thermodynamic regime. Such a contribution was found in all of the above-mentioned cities. Maximum of NO concentration is observed at crossroads of the main highways and decreases away from them. It should be noted that the NO distribution almost the same as the distribution of CO, which is also of "automobile engine" origin. In the center of cities where usually impurities are accumulated, concentration of SO2, NO2, CO, and aerosol number density as well are several times higher than in the city periphery. On the contrary, the ozone content in center is much lower. In most of the cases, the urban samples have 2-3 times more chemical elements than the background samples. The total concentrations of PAHs in aerosol matter of the cities varied from 20 to 30 ng/m3. PAH concentrations, as well as the percentage relation between them are determined by the place of aerosol sampling, i.e., by locations of pollution sources. Among the identified PAHs in the public green space and industrial zones of Angarsk, the predominating species are phenanthrene, pyrene, and fluoranthene, whose total amount reaches 80% of the mass of the detected PAHs. In summer, owing to more effective atmospheric ventilation, the effects of local circulation substantially weaken. As a result, a significant pollutant accumulation in the central parts of the cities may not always be detected.

Belan, B. D.; Ivlev, G. A.; Kozlov, A. S.; Marinaite, I. I.; Peneko, V. V.; Simonenkov, D. V.; Fofonov, A. V.; Khodzher, T. V.; Arshinov, M. Yu.

2009-04-01

111

Curious City  

NSDL National Science Digital Library

Chicago, what are you curious about? That might serve as the tagline for the WBEZ radio program "Curious City," as it's an inquisitive program that asks its listeners that exact question. The public submits queries about Chicago here on the show's site, visitors vote for the questions they like the best, and then the crack team at Curious City investigates and reports back, complete with help from locals who want to be part of the whole recursive process. On the site, visitors can look over the Up For Voting area, which includes questions that cover everything from Cook County Hospital to the design of Wrigley Field. For complete audio and written answers to questions that are wrapped up, click on over to the Answered & Investigating area. Here visitors can look over questions such as "Will the Pullman neighborhood ever be revitalized?" and "What is the origin of Chicago's distinctive wooden fire escapes?"

112

76 FR 54288 - Notice of Final Federal Agency Actions on Proposed Bridge and Approach Roadways in Nevada and...  

Federal Register 2010, 2011, 2012, 2013, 2014

...1). The actions relate to the proposed Laughlin-Bullhead City Bridge project in Laughlin, Clark County, Nevada; and in Bullhead...multi-use pathway) from Needles Highway in Laughlin, Clark County, Nevada (the west end)...

2011-08-31

113

Deposition of Histone Variant H2A.Z within Gene Bodies Regulates Responsive Genes  

PubMed Central

The regulation of eukaryotic chromatin relies on interactions between many epigenetic factors, including histone modifications, DNA methylation, and the incorporation of histone variants. H2A.Z, one of the most conserved but enigmatic histone variants that is enriched at the transcriptional start sites of genes, has been implicated in a variety of chromosomal processes. Recently, we reported a genome-wide anticorrelation between H2A.Z and DNA methylation, an epigenetic hallmark of heterochromatin that has also been found in the bodies of active genes in plants and animals. Here, we investigate the basis of this anticorrelation using a novel h2a.z loss-of-function line in Arabidopsis thaliana. Through genome-wide bisulfite sequencing, we demonstrate that loss of H2A.Z in Arabidopsis has only a minor effect on the level or profile of DNA methylation in genes, and we propose that the global anticorrelation between DNA methylation and H2A.Z is primarily caused by the exclusion of H2A.Z from methylated DNA. RNA sequencing and genomic mapping of H2A.Z show that H2A.Z enrichment across gene bodies, rather than at the TSS, is correlated with lower transcription levels and higher measures of gene responsiveness. Loss of H2A.Z causes misregulation of many genes that are disproportionately associated with response to environmental and developmental stimuli. We propose that H2A.Z deposition in gene bodies promotes variability in levels and patterns of gene expression, and that a major function of genic DNA methylation is to exclude H2A.Z from constitutively expressed genes. PMID:23071449

Coleman-Derr, Devin; Zilberman, Daniel

2012-01-01

114

Az optimista EPS el?rejelzési hiba viselkedéstani okai. Az EPS el?rejelzések vizsgálata magyar és osztrák viszonylatban = The behavioural motives of the optimistic EPS forecasting error Analysing Hungarian and Austrian companies’ EPS forecasts.  

E-print Network

??Dolgozatom témája a pénzügyi tervezés, ezen belül is az EPS el?rejelzések tervezési hibájának vizsgálata. Az EPS el?rejelzésben tapasztalható szisztematikus optimizmusra számos empirikus bizonyíték áll rendelkezésre… (more)

Jáki, Erika

2013-01-01

115

Mixer pump test plan for double shell tank AZ-101  

SciTech Connect

Westinghouse Hanford Company has undertaken the task to develop and demonstrate a method of retrieval for double-shell tank (DST)waste. Mixer pumps were chosen as the planned method of retrieval for the DSTs, based on engineering technology studies,past experience with hydraulic sluicing at the Hanford Site, and experience with mixer pumps at the Westinghouse Savannah River Site. This document outlines a test plan to demonstrate the ability of two 300 hp mixer pumps installed in the AZ-101 tank to mobilize waste.

Symons, G.A.; Staehr, T.W., Westinghouse Hanford

1996-06-01

116

75 FR 76924 - Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...Docket No. 10-AWP-5] Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ AGENCY: Federal Aviation...SUMMARY: This action will modify Class D and E airspace at Flagstaff, AZ, to accommodate...

2010-12-10

117

75 FR 61660 - Proposed Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...10-AWP-5 Proposed Modification of Class D and E Airspace, and Revocation of Class E Airspace; Flagstaff, AZ AGENCY: Federal Aviation...SUMMARY: This action proposes to modify Class D and E airspace at Flagstaff, AZ, to accommodate...

2010-10-06

118

Functional analysis of the histone variant H2A.Z during lineage commitment  

E-print Network

remained enigmatic. In this thesis, we dissect the role of H2A.Z during lineage commitment. In particular, we focused on the Polycomb-mediated mono-ubiquitylation of H2A.Z. We found that this modification regulates the ...

Surface, Lauren E. (Lauren Elizabeth)

2014-01-01

119

ABOUT CALENDAR FEES ENROLLMENT RECORDS University Home MyUCSC People Calendars A-Z Index  

E-print Network

ABOUT CALENDAR FEES ENROLLMENT RECORDS University Home MyUCSC People Calendars A-Z Index OFFICE OF THE REGISTRAR Chancellor's Welcome About Fields of Study Calendar Undergraduate Expenses Undergraduate Admission CALENDAR FEES ENROLLMENT RECORDS University Home MyUCSC People Calendars A-Z Index OFFICE OF THE REGISTRAR

California at Santa Cruz, University of

120

City of Anaheim City Manager's Office  

E-print Network

City of Anaheim City Manager's Office Volunteer Web Design Intern Job Description 1 The City of Anaheim seeks an intern to assist the City Manager's Office in graphic design with an emphasis on web design. This internship will give the intern valuable real-world experience in web design, as well

de Lijser, Peter

121

401 S. McClintock, Tempe, AZ 85281 (480) 784-5995 phone (480) 968-7262 fax 1638 S. 7th Street, Phoenix, AZ 85034 (480) 257-4177 phone (480) 252-1386 fax  

E-print Network

401 S. McClintock, Tempe, AZ 85281 (480) 784-5995 phone (480) 968-7262 fax 1638 S. 7th Street, Phoenix, AZ 85034 (480) 257-4177 phone (480) 252-1386 fax 6001 S. Sossaman Road, Mesa, AZ 85212 (480) 988-7408 phone (480) 988-6576 fax RENTAL CAR REQUEST Driver #1, Name (please print) Work Phone Destination

Rhoads, James

122

Biaxial Deformation of the Magnesium Alloy AZ80  

NASA Astrophysics Data System (ADS)

The multiaxial deformation of magnesium alloys is important for developing reliable, robust models for both the forming of components and also analysis of in-service performance of structures, for example, in the case of crash worthiness. The current study presents a combination of unique biaxial experimental tests and biaxial crystal plasticity simulations using a visco-plastic self-consistent (VPSC) formulation conducted on a relatively weak AZ80 cast texture. The experiments were conducted on tubular samples which are loaded in axial tension or compression along the tube and with internal pressure to generate hoop stresses orthogonal to the axial direction. The results were analyzed in stress and strain space and also in terms of the evolution of crystallographic texture. In general, it was found that the VPSC simulations matched well with the experiments. However, some differences were observed for cases where basal slip and \\{ {10bar{1}2} \\} extension twinning were in close competition such as in the biaxial tension quadrant of the plastic potential. The evolution of texture measured experimentally and predicted from the VPSC simulations was qualitatively in good agreement. Finally, experiments and VPSC simulations were conducted on a second AZ80 material which had a stronger initial texture and a higher level of mechanical anisotropy. In the previous case, the agreement between experiments and simulations was good, but a larger difference was observed in the biaxial tension quadrant of the plastic potential.

Tomlinson, P.; Azizi-Alizamini, H.; Poole, W. J.; Sinclair, C. W.; Gharghouri, M. A.

2013-07-01

123

Learning Cities as Healthy Green Cities: Building Sustainable Opportunity Cities  

ERIC Educational Resources Information Center

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…

Kearns, Peter

2012-01-01

124

Box City Curriculum.  

ERIC Educational Resources Information Center

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…

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

125

Sprawl City  

NSDL National Science Digital Library

Created by environmental authors Leon Kolankiewicz and Roy Beck, Sprawl City is a site dedicated to informing and assisting the general public about the issues of sprawl and rural land lost in the United States. With oversight from a variety of academic and practicing planners, the site contains a host of information about the growing rate of sprawl among urbanized and urbanizing areas across the country. Most helpful are a series of studies by Kolankiewicz and Beck investigating sprawl in several different states and regions, including California, Florida, Minnesota, and the Chesapeake Bay watershed. Along with all of their reports and studies, a section of definitions offers a more concrete explanation of how "sprawl" and other terms are technically defined.

126

Foreseeing critical phosphorus cycle transitions in constructed wetlands: applied to the new Tres Rios arid-land constructed wetlands with the city of Phoenix  

E-print Network

Foreseeing critical phosphorus cycle transitions in constructed wetlands: applied to the new Tres Rios arid-land constructed wetlands with the city of Phoenix E.Chapman1 and B.Warner2 1 School of Life Sciences, 2 School of Sustainability, Arizona State University,Tempe, AZ Abstract Constructed wetland

Hall, Sharon J.

127

Fabrication and characterization of AZ91/CNT magnesium matrix composites  

NASA Astrophysics Data System (ADS)

Carbon Nano Tube (CNT) reinforced AZ91 metal matrix composites (MMC) were fabricated by the squeeze infiltrated method. Properties of magnesium alloys have been improved by impurity reduction, surface treatment and alloy design, and thus the usage for the magnesium alloys has been extended recently. However there still remain barriers for the adaption of magnesium alloys for engineering materials. In this study, we report light-weight, high strength heat resistant magnesium matrix composites. Microstructural study and tensile test were performed for the squeeze infiltrated magnesium matrix composites. The wear properties were characterized and the possibility for the application to automotive power train and engine parts was investigated. It was found that the squeeze infiltration technique is a proper method to fabricate magnesium matrix composites reducing casting defects such as pores and matrix/reinforcement interface separation etc. Improved tensile and mechanical properties were obtained with CNT reinforcing magnesium alloys

Park, Yong-Ha; Park, Yong-Ho; Park, Ik-Min; Oak, Jeong-jung; Kimura, Hisamichi; Cho, Kyung-Mox

2008-12-01

128

Mineral Mapping Using AVIRIS Data at Ray Mine, AZ  

NASA Technical Reports Server (NTRS)

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.

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

1998-01-01

129

Influence of deformation on precipitation in AZ80 magnesium alloy  

NASA Astrophysics Data System (ADS)

Precipitates in the conventionally processed (solution treatment followed by aging) AZ80 alloy are coarse, cellular, and incoherent. They nucleate and grow on the basal planes of the matrix or distribute discontinuously in the alloy. Their unique morphology and undesired distribution make them ineffective for precipitation strengthening. This condition, however, can be modified by applying selected deformation and heat treatment conditions. The effect of deformation and heat treatment on the morphology and distribution of precipitates has been studied. Deformation was introduced by hot extrusion, cold rolling, or equal channel angular pressing (ECAP). The microstructures were characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results showed that cold deformation improved precipitation more significantly than hot deformation, and twinning promoted precipitation more effectively than slip. When ECAP was applied, the Bc-route induced more precipitates than the A-route.

Yang, Ping; Wang, Li-Na; Xie, Qing-Ge; Li, Ji-Zhong; Ding, Hua; Lu, Lin-Lin

2011-06-01

130

Project W-211 Initial Tank Retrieval Systems (ITRS) Description of Operations for 241-AZ-102  

SciTech Connect

The primary purpose of the Initial Tank Retrieval Systems (ITRS) is to provide systems for retrieval of radioactive wastes stored in underground double-shell tanks (DSTs) for transfer to alternate storage, evaporation, pretreatment or treatment, while concurrently reducing risks associated with safety watch list and other DSTs. This Description of Operation (DOO) defines the control philosophy for the waste retrieval system for Tank 241-AZ-102 (AZ-102). This DOO provides a basis for the detailed design of the Project W-211 Retrieval Control System (RCS) for AZ-102 and also establishes test criteria for the RCS.

BRIGGS, S.R.

2000-02-25

131

System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System  

SciTech Connect

Describes the hardware and software for the AZ-101 Mixer Pump Data Acquisition System. The purpose of the tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste (NCAW), and eventual disposal as glass via the Hanford Waste Vitrification Plant.

ROMERO, S.G.

2000-01-10

132

Clean Cities Fact Sheet  

SciTech Connect

This fact sheet explains the Clean Cities Program and provides contact information for all coalitions and regional offices. It answers key questions such as: What is the Clean Cities Program? What are alternative fuels? How does the Clean Cities Program work? What sort of assistance does Clean Cities offer? What has Clean Cities accomplished? What is Clean Cities International? and Where can I find more information?

Not Available

2004-01-01

133

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

Federal Register 2010, 2011, 2012, 2013, 2014

...2013. ADDRESSES: Dr. Bruce Anderson, Forensic Anthropologist, PCOME, Tucson, AZ...County Medical Examiner's Office for forensic analysis. The Pinal County Medical Examiner...Medical Examiner for examination by a forensic anthropologist. Dr. Bruce...

2013-10-31

134

78 FR 40503 - Notice of Realty Action: Direct Sale of Public Lands in Pima County, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...Management (BLM), Tucson Field Office (TFO...Field Manager, BLM Tucson Field Office, 3201 East Universal Way, Tucson, AZ 85756. FOR FURTHER INFORMATION CONTACT: Linda Dunlavey...an important public project for the...

2013-07-05

135

Draft Genome Sequence of Lysobacter capsici AZ78, a Bacterium Antagonistic to Plant-Pathogenic Oomycetes.  

PubMed

Lysobacter capsici AZ78, isolated from tobacco rhizosphere, effectively controls Phytophthora infestans and Plasmopara viticola on tomato and grapevine plants, respectively. We report the first draft genome sequence of the L. capsici species. PMID:24762937

Puopolo, Gerardo; Sonego, Paolo; Engelen, Kristof; Pertot, Ilaria

2014-01-01

136

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

Federal Register 2010, 2011, 2012, 2013, 2014

...TA-W-71,855A] Freescale Semiconductor, Inc., Technical Information Center, Tempe, AZ; Freescale Semiconductor, Inc., Technical Information...applicable to workers of Freescale Semiconductor, Inc., Technical...

2010-08-13

137

Szisztémás lupus erythmatosusos betegek követésével szerzett tapasztalataim, különös tekinettel az antifoszfolipid antitestek jelent?ségére.  

E-print Network

??1. Anti-foszfolipid antitest pozitív SLE-s betegekben a klinikailag manifeszt trombózis kialakulásának esélyét a következ? tényez?k fokozzák: a. A lupus antikoaguláns jelenléte fokozott rizikót jelent, az… (more)

Tarr, Tünde

2007-01-01

138

Operational Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer  

SciTech Connect

This document comprises the Operational Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer. The objective of the testing was to verify that all equipment and components functioned as designed following construction completion and turnover to operations.

ANDREWS, J.E.

2000-03-28

139

75 FR 10552 - Noise Exposure Map Notice for Chandler Municipal Airport, Chandler, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...15000 Aviation Boulevard, Lawndale, CA 90261; Greg Chenoweth, Airport Manager, Chandler Municipal Airport, 2380 South Stinson Way, Chandler, AZ 85249. Questions may be directed to the individual named above under the heading, FOR FURTHER...

2010-03-08

140

Draft Genome Sequence of Lysobacter capsici AZ78, a Bacterium Antagonistic to Plant-Pathogenic Oomycetes  

PubMed Central

Lysobacter capsici AZ78, isolated from tobacco rhizosphere, effectively controls Phytophthora infestans and Plasmopara viticola on tomato and grapevine plants, respectively. We report the first draft genome sequence of the L. capsici species. PMID:24762937

Sonego, Paolo; Engelen, Kristof; Pertot, Ilaria

2014-01-01

141

76 FR 64041 - Proposed Amendment of Class E Airspace; Show Low, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...Airport, Show Low, AZ. Controlled airspace is necessary to accommodate aircraft using Area Navigation (RNAV) Global Positioning System (GPS) standard instrument approach procedures at Show Low Regional Airport. The FAA is proposing this...

2011-10-17

142

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Retarding Structure (FRS) Supplemental Watershed Plan, Pinal County, AZ AGENCY: Natural...Retarding Structure (FRS) Supplemental Watershed Plan, Pinal County, Arizona. FOR FURTHER...Domestic Assistance under No. 10.904, Watershed Protection and Flood Prevention,...

2010-05-24

143

76 FR 62144 - Environmental Impact Statement for Implementation of Passenger Rail Service Between Tucson, AZ...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Statement for Implementation of Passenger Rail Service Between Tucson, AZ and Phoenix...to study the implementation of passenger rail service between Tucson, Arizona and Phoenix...build alternatives that provide intercity rail service. Identifying the...

2011-10-06

144

Effect of Carbon Nanotube on High-Temperature Formability of AZ31 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

Room-temperature tensile properties of AZ31 alloy have significantly been improved when reinforced with carbon nanotube via ingot metallurgy process. However, high-temperature (up to 250 °C) elongation-to-failure tensile test of the developed nanocomposite revealed a considerable softening in the AZ31 alloy matrix accompanied by an incredible ductility increment (up to 132%). Microstructural characterization of the fractured samples revealed that the dynamic recrystallization process has induced a complete recrystallization in the AZ31 alloy at a lower temperature (150 °C) followed by substantial grain growth at a higher temperature used in this study. Fractography on the fractured surfaces revealed that the room-temperature mixed brittle-ductile modes of fracture behavior of AZ31 alloy have transformed into a complete ductile mode of fracture at high temperature.

Hassan, S. Fida; Paramsothy, M.; Gasem, Z. M.; Patel, F.; Gupta, M.

2014-08-01

145

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Ehrenberg, First Mesa, Kachina Village, Wickenburg, and Williams, AZ, and Needles, CA AGENCY: Federal Communications Commission...DC 20554. FOR FURTHER INFORMATION CONTACT: Rolanda F. Smith or Andrew J. Rhodes, Media Bureau, (202)...

2012-01-17

146

Electrochemical corrosion behavior of composite coatings of sealed MAO film on magnesium alloy AZ91D  

Microsoft Academic Search

Protective composite coatings were prepared on magnesium alloy AZ91D by micro-arc oxidation (MAO) treatment plus a top coating with sealing agent using multi-immersion technique under low-pressure conditions. The corrosion resistance of AZ91D alloy with composite coatings was superior evidently to that with merely MAO film. SEM observations revealed that the sealing agent was integrated with MAO film by physically interlocking;

Hongping Duan; Keqin Du; Chuanwei Yan; Fuhui Wang

2006-01-01

147

Kinetics of recrystallization for twin-roll casting AZ31 magnesium alloy during homogenization  

Microsoft Academic Search

The kinetics of recrystallization for twin-roll casting AZ31 magnesium alloy with different thicknesses during homogenization was analyzed. It is shown that fine grains are first formed at the boundaries of deformed bands in the twin-roll casting slab. The recrystallized grains with no strain are gradually substituted for the deformed microstructure of twin-roll casting AZ31 magnesium alloy. The incubation temperature and

Hu Zhao; Pei-Jie Li; Liang-Ju He

2011-01-01

148

Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer  

SciTech Connect

This document comprises the Acceptance Test Report for the 241-AZ-101 Ultrasonic Interface Level Analyzer. This document presents the results of Acceptance Testing of the 241-AZ-101 Ultrasonic Interface Level Analyzers (URSILLAs). Testing of the URSILLAs was performed in accordance with ATP-260-001, ''URSILLA Pre-installation Acceptance Test Procedure''. The objective of the testing was to verify that all equipment and components function in accordance with design specifications and original equipment manufacturer's specifications.

ANDREWS, J.E.

2000-01-27

149

Final results of double-shell tank 241-AZ-101 ultrasonic inspection  

SciTech Connect

This document presents the results and documentation of the nondestructive ultrasonic examination of tank 241-AZ-101. A tank inspection supplier was retained to provide and use an ultrasonic examination system (equipment, procedures, and inspectors) to scan a limited area of double-shell tank 241-AZ-101 primary tank wall and welds. The inspection found one reportable indication of thinning and no reportable pitting, corrosion, or cracking.

JENSEN, C.E.

1999-08-23

150

IEEE 802.3az: the road to energy efficient ethernet  

Microsoft Academic Search

Ethernet is the dominant wireline communications technology for LANs with over 1 billion interfaces installed in the U.S. and over 3 billion worldwide. In 2006 the IEEE 802.3 Working Group started an effort to improve the energy efficiency of Ethernet. This effort became IEEE P802.3az Energy Efficient Ethernet (EEE) resulting in IEEE Std 802.3az-2010, which was approved September 30, 2010.

Ken Christensen; Pedro Reviriego; B. Nordman; M. Bennett; M. Mostowfi; Juan Antonio Maestro

2010-01-01

151

Microstructure evolution of AZ31 Mg alloy during equal channel angular extrusion  

Microsoft Academic Search

Microstructure evolution of AZ31 Mg alloy during equal-channel angular extrusion (ECAE) was investigated. The grains of AZ31 Mg alloy were refined significantly after extruded one to eight passes at 498K. Dislocations were induced at the initial stage of extrusion and they rearranged themselves to form dislocation boundaries and sub-grain boundaries during deformation. As strain increased, the newly created dislocations in

Li Jin; Dongliang Lin; Dali Mao; Xiaoqing Zeng; Bin Chen; Wenjiang Ding

2006-01-01

152

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

Microsoft Academic Search

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

Hays

1998-01-01

153

Series expansions for the incomplete Lipschitz-Hankel integral Ye0(a,z)  

Microsoft Academic Search

Three series expansions are derived for the incomplete Lipschitz-Hankel integral Ye0(a,z) for complex-valued a and z. Two novel expansions are obtained by using contour integration techniques to evaluate the inverse Laplace transform representation for Ye0(a,z). A third expansion is obtained by replacing the Neumann function by its Neumann series representation and integrating the resulting terms. An algorithm is outlined which

Mehdi M. Mechaik; Steven L. Dvorak

1996-01-01

154

Series expansions for the incomplete Lipschitz-Hankel integral Je0(a,z)  

Microsoft Academic Search

Bessel series expansions are derived for the incomplete Lipschitz-Hankel integral Je0(a,z). These expansions are obtained by using contour integration techniques to evaluate the inverse Laplace transform representation for Je0(a,z). It is shown that one of the expansions can be used as a convergent series expansion for one definition of the branch cut and as an asymptotic expansion if the branch

Mehdi M. Mechaik; Steven L. Dvorak

1995-01-01

155

System Description for Tank 241-AZ-101 Waste Retrieval Data Acquisition System  

SciTech Connect

The proposed activity provides the description of the Data Acquisition System for Tank 241-AZ-101. This description is documented in HNF-5572, Tank 241-AZ-101 Waste Retrieval Data Acquisition System (DAS). This activity supports the planned mixer pump tests for Tank 241-AZ-101. Tank 241-AZ-101 has been selected for the first full-scale demonstration of a mixer pump system. The tank currently holds over 960,000 gallons of neutralized current acid waste, including approximately 12.7 inches of settling solids (sludge) at the bottom of the tank. As described in Addendum 4 of the FSAR (LMHC 2000a), two 300 HP mixer pumps with associated measurement and monitoring equipment have been installed in Tank 241-AZ-101. The purpose of the Tank 241-AZ-101 retrieval system Data Acquisition System (DAS) is to provide monitoring and data acquisition of key parameters in order to confirm the effectiveness of the mixer pumps utilized for suspending solids in the tank. The suspension of solids in Tank 241-AZ-101 is necessary for pretreatment of the neutralized current acid waste and eventual disposal as glass via the Hanford Waste Vitrification Plant. HNF-5572 provides a basic description of the Tank 241-AZ-101 retrieval system DAS, including the field instrumentation and application software. The DAS is provided to fulfill requirements for data collection and monitoring. This document is not an operations procedure or is it intended to describe the mixing operation. This USQ screening provides evaluation of HNF-5572 (Revision 1) including the changes as documented on ECN 654001. The changes include (1) add information on historical trending and data backup, (2) modify DAS I/O list in Appendix E to reflect actual conditions in the field, and (3) delete IP address in Appendix F per Lockheed Martin Services, Inc. request.

ROMERO, S.G.

2000-02-14

156

Effect of microstructure on the zinc phosphate conversion coatings on magnesium alloy AZ91  

NASA Astrophysics Data System (ADS)

The effect of the microstructure, particularly of ?-Mg17Al12 phase, on the formation and growth of zinc phosphate conversion coatings on magnesium alloy AZ91 (AZ91) was studied. The zinc phosphate coatings were formed on AZ91 with different microstructures produced by heat treatment. The effect of the microstructure on the zinc phosphate coatings were examined using optical microscope (OM), X-ray diffraction (XRD), coatings weight and etching weight balances, scanning electron microscopy (SEM) and salt immersion test. Results showed that as-cast AZ91 contained a high volume fraction of the ?-Mg17Al12 phase and it was dissolved into ?-Mg phase during heat treatment at 400 °C. The ?-phase became center for hydrogen evolution during phosphating reaction (cathodic sites). The decreased volume fraction of the ?-phase caused decreasing both coatings weight and etching weight of the phosphating process. However, it increased the crystal size of the coatings and improved corrosion resistance of AZ91 by immersing in 0.5 M NaCl solution. Results also showed that the structure of the zinc phosphate conversion on AZ91 consisted of two layers: an outer crystal Zn3(PO4)2ˇ4H2O (hopeite) and an inner which was mainly composed of MgZn2(PO4)2 and Mg3(PO4)2. A mechanism for the formation of two layers of the coatings was also proposed in this study.

Van Phuong, Nguyen; Moon, Sungmo; Chang, Doyon; Lee, Kyu Hwan

2013-01-01

157

Effect of Ca and Rare Earth Elements on Impression Creep Properties of AZ91 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

Creep properties of AZ91 magnesium alloy and AZRC91 (AZ91 + 1 wt pct RE + 1.2 wt pct Ca) alloy were investigated using the impression creep method. It was shown that the creep properties of AZ91 alloy are significantly improved by adding Ca and rare earth (RE) elements. The improvement in creep resistance is mainly attributed to the reduction in the amount and continuity of eutectic ?(Mg17Al12) phase as well as the formation of new Al11RE3 and Al2Ca intermetallic compounds at interdendritic regions. It was found that the stress exponent of minimum creep rate, n, varies between 5.69 and 6 for AZ91 alloy and varies between 5.81 and 6.46 for AZRC91 alloy. Activation energies of 120.9 ą 8.9 kJ/mol and 100.6 ą 7.1 kJ/mol were obtained for AZ91 and AZRC91 alloys, respectively. It was shown that the lattice and pipe-diffusion-controlled dislocation climb are the dominant creep mechanisms for AZ91 and AZRC91 alloys, respectively. The constitutive equations, correlating the minimum creep rate with temperature and stress, were also developed for both alloys.

Nami, B.; Razavi, H.; Mirdamadi, S.; Shabestari, S. G.; Miresmaeili, S. M.

2010-08-01

158

Fine particulate chemical composition and light extinction at Meadview, AZ  

SciTech Connect

The concentration of fine particulate nitrate, sulfate, and carbonaceous material was measured for 12-hr daynight samples using diffusion denuder samplers during the Project Measurement of Haze and Visibility Effects (MOHAVE) July to August 1992 Summer Intensive study at Meadview, AZ, just west of Grand Canyon National Park. Organic material was measured by several techniques. Only the diffusion denuder method measured the semivolatile organic material. Fine particulate sulfate and nitrate (using denuder technology) determined by various groups agreed. Based on the various collocated measurements obtained during the Project MOHAVE study, the precision of the major fine particulate species was {+-} 0.6 {mu}g/m{sup 3} organic material, {+-} 0.3 {mu}g/m{sup 3} ammonium sulfate, and {+-} 0.07 {mu}g/m{sup 3} ammonium nitrate. Fine particulate organic material was the principal particulate contributor to light extinction during the study period, with fine particulate sulfate as the second most important contributor. Particle light extinction was dominated by sulfate and organic material during periods of lowest light extinction. Combination of the extinction data and chemical mass balance analysis of sulfur oxides sources in the region indicate that the major anthropogenic contributors to light extinction were from the Los Angeles, CA, and Las Vegas, NV, urban areas. Mohave Power Project associated secondary sulfate was a negligible contributor to light extinction. 49 refs., 12 figs., 7 tabs.

Delbert J. Eatough; Wenxuan Cui; Jeffery Hull; Robert J. Farber [Brigham Young University, Provo, UT (United States). Department of Chemistry and Biochemistry

2006-12-15

159

Jerusalem: City of Dreams, City of Sorrows  

ERIC Educational Resources Information Center

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…

Ricks, Thomas

2011-01-01

160

Dose rate analysis for Tank 101 AZ (Project W151)  

SciTech Connect

This document describes the expected dose rates for modification to tank 101 AZ including modifications to the steam coil, mixer pump, and temperature probes. The thrust of the effort is to determine dose rates from: modification of a steam coil and caisson; the installation of mixer pumps; the installation of temperature probes; and estimates of dose rates that will be encountered while making these changes. Because the dose rates for all of these configurations depend upon the photon source within the supernate and sludge, comparisons were also made between measured dose rates within a drywell and the corresponding calculated dose rates. The calculational tool used is a Monte Carlo (MCNP{sub 2}) code since complicated three dimensional geometries are involved. A summary of the most important results of the entire study is given in Section 2. The basic calculational geometry model of the tank is discussed in Section 3, along with a tabulation of the photon sources that were used within the supernate and the sludge, and a discussion of uncertainties. The calculated dose rates around the steam coil and caisson before and after modification are discussed in Section 4. The configuration for the installation of the mixer pumps and the resulting dose rates are given in Section 5. The predicted changes in dose rates due to a possible dilution of the supernate source are given in Section 6. The calculational configuration used to model the installation of temperature probes and the resulting predicted dose rates are discussed in Section 7. Finally, comparisons of measured to calculated dose rates within a drywell are summarized in Section 8. Extended discussions of calculational models and Monte Carlo optimization techniques used are included in Appendix A.

Schwarz, R.A.; Hillesland, K.E.; Carter, L.L.

1994-11-01

161

What Is Clean Cities?  

SciTech Connect

This Clean Cities Program fact sheet describes the purpose and scope of this DOE program. Clean Cities facilitates the use of alternative and advanced fuels and vehicles to displace petroleum in the transportation sector.

Not Available

2007-08-01

162

Cities and Sustainable Development  

E-print Network

of cities in today's world economy is unprecedented. Until the Industrial Revolution, human history. The information and communications revolution has spawned the idea of the "smart city," which places the relevant

163

Assimilation in Multilingual Cities  

Microsoft Academic Search

Using the Public Use Microdata Files of the 2001 and 2006 Canadian Censuses, we study the determinants of the assimilation of language minorities into the city majority language. We show that official minority members (i.e. francophones in English-speaking cities and anglophones in French-speaking cities) assimilate less than the \\

Javier Ortega; Gregory Verdugo

2011-01-01

164

Cities and Homeowners Associations  

Microsoft Academic Search

In his recent article, The City as a Legal Concept, Professor Gerald Frug compared the city and the business corporation as possible vehicles for the exercise of decentralized power. In the course of his analysis, Frug asserted that American law is deeply biased against the emergence of powerful cities and, by implication, is less restrictive on corporate power. Joining the

Robert C. Ellickson

1982-01-01

165

INEQUALITY IN CITIES  

Microsoft Academic Search

Much of the inequality literature has focused on national inequality, but local inequality is also important. Crime rates are higher in more unequal cities; people in unequal cities are more likely to say that they are unhappy. There is a negative association between local inequality and the growth of city-level income and population, once we control for the initial distribution

Edward L. Glaeser; Matt Resseger; Kristina Tobio

2009-01-01

166

INEQUALITY IN CITIES &ast  

Microsoft Academic Search

ABSTRACT.?Much of the inequality literature has focused on national inequality, but local inequality is also important. Crime rates are higher in more unequal cities; people in unequal cities are more likely to say that they are unhappy. There is a negative association between local inequality and the growth of city-level income and population, once we control for the initial distribution

Edward L. Glaeser; Matt Resseger; Kristina Tobio

2009-01-01

167

Formation of intermetallic compound coating on magnesium AZ91 cast alloy  

NASA Astrophysics Data System (ADS)

This study describes an intermetallic compound coating formed on AZ91 Mg cast alloy. The Al sputtered on AZ91 cast alloy reacted with substrate during a short period of heat treatment at 435°C, resulting in the formation of a continuous intermetallic compound layer. The short period treatment has the advantage of minimizing the negative effect on the microstructure of substrate and the mechanical properties, comparing with the reported diffusion coatings. DSC measurement and examination on the cross-section of Al sputtered samples show that local melting occurred along the Al/substrate interface at the temperature range between 430~435°C. The formation mechanism of intermetallic compound coating is proposed in terms of the local melting at Al/substrate interface. The salt water immersion test showed significant improvement in corrosion resistance of the intermetallic compound coated AZ91 cast alloy compared with the as-cast alloys.

Zhu, Tianping; Gao, Wei

2009-08-01

168

Study of thermal properties of metallic samples AZ91E/ALN  

NASA Astrophysics Data System (ADS)

Using the open photoacoustic cell technique, we obtained the spectra of the photoacoustic signal amplitude as a function of the modulation frequency of the incident radiation. From these spectra we determined the thermal diffusivity in Mg- AZ91E/AlN metal matrix composite with a magnesium alloy of around 9% aluminum and 1% zinc, the aluminum nitrade (AlN) is a ceramic with relationship AlN/AZ91E with ratio 1:1. The photoacoustic signal amplitude in the region thermally thick and optically opaque is used to calculate the thermal diffusivity of the Mg-AZ91E/AlN material and the results obtained are shown.

Cruz Mandujano, Javier; Egberto Bedolla, Becerril; Villafańa Rauda, Edgar

2011-08-01

169

Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan  

SciTech Connect

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications.

TEMPLETON, A.M.

2000-01-31

170

Tank 241-AZ-101 Mixer Pump Test Vapor Sampling and Analysis Plan  

SciTech Connect

This sampling and analysis plan (SAP) identifies characterization objectives pertaining to sample collection, laboratory analytical evaluation, and reporting requirements for vapor samples obtained during the operation of mixer pumps in tank 241-AZ-101. The primary purpose of the mixer pump test (MPT) is to demonstrate that the two 300 horsepower mixer pumps installed in tank 241-AZ-101 can mobilize the settled sludge so that it can be retrieved for treatment and vitrification. Sampling will be performed in accordance with Tank 241-AZ-101 Mixer Pump Test Data Quality Objective (Banning 1999) and Data Quality Objectives for Regulatory Requirements for Hazardous and Radioactive Air Emissions Sampling and Analysis (Mulkey 1999). The sampling will verify if current air emission estimates used in the permit application are correct and provide information for future air permit applications.

TEMPLETON, A.M.

2000-03-06

171

Blocking spinal CCR2 with AZ889 reversed hyperalgesia in a model of neuropathic pain  

PubMed Central

Background The CCR2/CCL2 system has been identified as a regulator in the pathogenesis of neuropathy-induced pain. However, CCR2 target validation in analgesia and the mechanism underlying antinociception produced by CCR2 antagonists remains poorly understood. In this study, in vitro and in vivo pharmacological approaches using a novel CCR2 antagonist, AZ889, strengthened the hypothesis of a CCR2 contribution to neuropathic pain and provided confidence over the possibilities to treat neuropathic pain with CCR2 antagonists. Results We provided evidence that dorsal root ganglia (DRG) cells harvested from CCI animals responded to stimulation by CCL2 with a concentration-dependent calcium rise involving PLC-dependent internal stores. This response was associated with an increase in evoked neuronal action potentials suggesting these cells were sensitive to CCR2 signalling. Importantly, treatment with AZ889 abolished CCL2-evoked excitation confirming that this activity is CCR2-mediated. Neuronal and non-neuronal cells in the spinal cord were also excited by CCL2 applications indicating an important role of spinal CCR2 in neuropathic pain. We next showed that in vivo spinal intrathecal injection of AZ889 produced dose-dependent analgesia in CCI rats. Additionally, application of AZ889 to the exposed spinal cord inhibited evoked neuronal activity and confirmed that CCR2-mediated analgesia involved predominantly the spinal cord. Furthermore, AZ889 abolished NMDA-dependent wind-up of spinal withdrawal reflex pathway in neuropathic animals giving insight into the spinal mechanism underlying the analgesic properties of AZ889. Conclusions Overall, this study strengthens the important role of CCR2 in neuropathic pain and highlights feasibility that interfering on this mechanism at the spinal level with a selective antagonist can provide new analgesia opportunities. PMID:21143971

2010-01-01

172

An Empirical Test of the Relationship between Sustainability and Urban Form Based on Indicator Comparisons using Sustainlane Sustainable City Rankings  

E-print Network

, New York and Philadelphia raked as the least sprawling of the 13 and Atlanta and Miami as the most sprawling. The disadvantage of this research is its availability of only 13 areas (Ewing et al., 2002). 14 3. US SUSTAINABLE CITY RANKING... City, MO 37 Fresno, CA 4 Chicago, IL 21 San Jose, CA 38 El Paso, TX 5 New York, NY 22 Tucson, AZ 39 Fort Worth, TX 6 Boston, MA 23 Jacksonville, FL 40 Nashville, TN 7 Minneapolis, MN 24 Dallas, TX 41 Arlington, TX 8 Philadelphia, PA 25 Omaha, NE 42...

Kim, Bo Ah

2011-02-22

173

1301 S. 3rd Avenue Yuma, AZ 85364 ph: 928-782-5113 fax: 928-783-0866  

E-print Network

and Edius, or some knowledge of editing on other editing systems. Also, News Techs will be asked to shoot-TV, Yuma, AZ Serving Yuma, AZ and El Centro, CA Job Title: NEWS PRODUCTION TECHNICIAN (Part Time) Shift: TBD Duties: KSWT News 13 is looking for a News Production Technician. Duties include but not limit

Droegemeier, Kelvin K.

174

H2A.Z Acidic Patch Couples Chromatin Dynamics to Regulation of Gene Expression Programs during ESC Differentiation  

E-print Network

The histone H2A variant H2A.Z is essential for embryonic development and for proper control of developmental gene expression programs in embryonic stem cells (ESCs). Divergent regions of amino acid sequence of H2A.Z likely ...

Subramanian, Vidya

175

Shared Resources Reported at NCI-Designated Cancer Centers in 2013 A-Z Listing by Cancer Center Name  

Cancer.gov

Shared Resources Reported at NCI-Designated Cancer Centers in 2013 A-Z Listing by Cancer Center Name Page 1 of 34 Cancer Center Institution Resource Name Director(s) Shared Resources Reported at NCI-Designated Cancer Centers in 2013 A-Z Listing by Cancer Center Name Alvin J.

176

Draft Genome Sequence of the Sulfolobales Archaeon AZ1, Obtained through Metagenomic Analysis of a Mexican Hot Spring  

PubMed Central

The Sulfolobales archaea have been found inhabiting acidic hot springs all over the world. Here, we report the 1.798-Mbp draft genome sequence of the thermoacidophilic Sulfolobales archaeon AZ1, reconstructed from the metagenome of a Mexican hot spring. Sequence-based comparisons revealed that the Sulfolobales archaeon AZ1 represents a novel candidate genus. PMID:24604657

Martínez-Romero, Esperanza

2014-01-01

177

Effect of micro-texture on fracture location in friction stir weld of Mg alloy AZ61 during tensile test  

Microsoft Academic Search

Microstructural evolution of magnesium alloy AZ61 during friction stir welding and details of the relationship between the microstructure and mechanical properties are discussed. Tensile properties of the weld of Mg alloy AZ61 were strongly influenced by crystallographic orientation distribution as well as by grain size and dislocation density.

Seung Hwan C. Park; Yutaka S. Sato; Hiroyuki Kokawa

2003-01-01

178

Brain H2A.Z: the long and the short  

PubMed Central

The role of histone variants and their specific post-translational modifications (PTMs) in the epigenetic regulation of gene expression is still poorly understood. A paper published by Simonet and colleagues in Epigenetics and Chromatin describes a new H2A.Z subtype that is specific for brain and pituitary in the carp and provides additional information about the functional epigenetic complexity of the PTMs associated with histone H2A.Z. See research article: http://www.epigeneticsandchromatin.com/content/6/1/22 PMID:23866047

2013-01-01

179

No correlation between serotonin and its metabolite 5-HIAA in the cerebrospinal fluid and [(11) C]AZ10419369 binding measured with PET in healthy volunteers.  

PubMed

[(11) C]AZ10419369 is sensitive to pharmacologically enhanced endogenous serotonin levels. Twelve healthy volunteers underwent [(11) C]AZ10419369 PET and lumbar puncture. There were no correlations between [(11) C]AZ10419369 binding and concentrations of serotonin and its metabolite 5-HIAA in cerebrospinal fluid, suggesting that [(11) C]AZ10419369 brain binding does not reflect baseline serotonin levels in cerebrospinal fluid. PMID:24988901

Tiger, Mikael; Svenningsson, Per; Nord, Magdalena; Jabre, Sandra; Halldin, Christer; Lundberg, Johan

2014-10-01

180

Great Zoom out of the Grand Canyon, AZ  

NSDL National Science Digital Library

Using data from different spacecraft and some powerful computer technology, visualizers at the Goddard Space Flight Center present you with a collection of American cities in a way you have never seen them before. Starting with our camera high above the Earth, we rush in towards the surface at what would be an impossible speed for any known vehicle. Passing though layers of atmosphere, the colors of our destinations shimmer with their own unique characteristics, and suddenly we find ourselves floating in virtual space just above the ground.

Greg Shirah

2003-01-14

181

Victory City: The City of the Future  

NSDL National Science Digital Library

For the past 40-odd years, Orville Simpson II has been pursuing a dream, his vision of a city of the future, a Victory City based on reason and efficiency. Victory Cities would be entirely self-contained under one roof, ideally consisting of seven linked buildings -- each 102 stories -- containing residences, offices, industry, and retail space. Although the idea of snap-out modular walls, furniture bolted to the floors, and no kitchens (residents will be transported to the cafeterias by Ferris wheels) does not appeal to everyone, Simpson must be given credit for the depth and breadth of his vision. Users reading the Residents Guide will find that few details have been overlooked. Simpson addresses issues such as the money and food systems, education, postal service, transportation, security, recreation, pets, healthcare, ecological issues, and so on. Users can view numerous floor plans and conceptual drawings in the Victory City tour, review his arguments for the city in the Purpose/Benefits section, and read a collection of newspaper and magazine features on the man and his city in the Media Coverage section. Simpson is, by the way, still seeking investors.

182

Directional Solidification of Mg-Al Alloys and Microsegregation Study of Mg Alloys AZ31 and AM50: Part II. Comparison between AZ31 and AM50  

Microsoft Academic Search

Directional solidification (DS) of magnesium alloys AZ31 and AM50 was carried out to investigate microstructures and microsegregation\\u000a under controlled solidification conditions. The methodology used is based on a customized DS technique elaborated on in Part\\u000a I of this work. Dendritic microstructures observed in longitudinal sections of the quenched mushy zone, X-ray maps of fully\\u000a directionally solidified cross sections, and quantitative

Djordje Mirkovic; Rainer Schmid-Fetzer

2009-01-01

183

Anp32e, a higher eukaryotic histone chaperone directs preferential recognition for H2A.Z.  

PubMed

H2A.Z is a highly conserved histone variant in all species. The chromatin deposition of H2A.Z is specifically catalyzed by the yeast chromatin remodeling complex SWR1 and its mammalian counterpart SRCAP. However, the mechanism by which H2A.Z is preferentially recognized by non-histone proteins remains elusive. Here we identified Anp32e, a novel higher eukaryote-specific histone chaperone for H2A.Z. Anp32e preferentially associates with H2A.Z-H2B dimers rather than H2A-H2B dimers in vitro and in vivo and dissociates non-nucleosomal aggregates formed by DNA and H2A-H2B. We determined the crystal structure of the Anp32e chaperone domain (186-232) in complex with the H2A.Z-H2B dimer. In this structure, the region containing Anp32e residues 214-224, which is absent in other Anp32 family proteins, specifically interacts with the extended H2A.Z ?C helix, which exhibits an unexpected conformational change. Genome-wide profiling of Anp32e revealed a remarkable co-occupancy between Anp32e and H2A.Z. Cells overexpressing Anp32e displayed a strong global H2A.Z loss at the +1 nucleosomes, whereas cells depleted of Anp32e displayed a moderate global H2A.Z increase at the +1 nucleosomes. This suggests that Anp32e may help to resolve the non-nucleosomal H2A.Z aggregates and also facilitate the removal of H2A.Z at the +1 nucleosomes, and the latter may help RNA polymerase II to pass the first nucleosomal barrier. PMID:24613878

Mao, Zhuo; Pan, Lu; Wang, Weixiang; Sun, Jian; Shan, Shan; Dong, Qiang; Liang, Xiaoping; Dai, Linchang; Ding, Xiaojun; Chen, She; Zhang, Zhuqiang; Zhu, Bing; Zhou, Zheng

2014-04-01

184

Strategies to Reduce the Harmful Effects of Extreme Heat Events: A Four-City Study  

PubMed Central

Extreme heat events (EHEs) are becoming more intense, more frequent and longer lasting in the 21st century. These events can disproportionately impact the health of low-income, minority, and urban populations. To better understand heat-related intervention strategies used by four U.S. cities, we conducted 73 semi-structured interviews with government and non-governmental organization leaders representing public health, general social services, emergency management, meteorology, and the environmental planning sectors in Detroit, MI; New York City, NY; Philadelphia, PA and Phoenix, AZ—cities selected for their diverse demographics, climates, and climate adaptation strategies. We identified activities these leaders used to reduce the harmful effects of heat for residents in their city, as well as the obstacles they faced and the approaches they used to evaluate these efforts. Local leaders provided a description of how local context (e.g., climate, governance and city structure) impacted heat preparedness. Despite the differences among study cities, political will and resource access were critical to driving heat-health related programming. Upon completion of our interviews, we convened leaders in each city to discuss these findings and their ongoing efforts through day-long workshops. Our findings and the recommendations that emerged from these workshops could inform other local or national efforts towards preventing heat-related morbidity and mortality. PMID:24531122

White-Newsome, Jalonne L.; McCormick, Sabrina; Sampson, Natalie; Buxton, Miatta A.; O’Neill, Marie S.; Gronlund, Carina J.; Catalano, Linda; Conlon, Kathryn C.; Parker, Edith A.

2014-01-01

185

A-Z International/Exchange Student Guide (So your Bishop's Experience is easier)  

E-print Network

Laval University Quebec City, Canada RESEARCH INTERESTS Computational models of Human Communication. Computer vision and systems laboratory, Laval University 1998-1999 Research Assistant Quebec city, Canada

186

Radioisotope inventory of T101AZ thermocouple tree from riser 13D  

SciTech Connect

The radionuclide inventory for the thermocouple tree removed from tank T101-AZ riser 13D was estimated using measured {sup 137}Cs activity. This activity was measured by detectors as the tree was removed from the tank. Other radionuclide activities were estimated using the results of tank samples.

Kessler, S.F., Westinghouse Hanford

1996-06-12

187

Egy Gogol-szöveghely Puskin-hivatkozásáról (A démon cím? költemény szerepe Az arcképben)  

E-print Network

Portréban felderítend? intertextus ily módon nem els?sorban egy megidézett témát vagy jelentésalakzatot interpretál.2 Gogol e m?vében különleges módon méri a puskini értelmezési folyamatokhoz saját szövegbels? interpretációs eljárásait, és mindezt önnön... („????????????? ?????????????? ???????????, ??????????? ?????? ?. ?. ??????? ? ?. ? ??????”). A konferencia kötete orosz nyelven fogja tartalmazni az el?adást. 2 ? démon motívumáról a lírai frazeológia elemeként ld.: ?????????? 1969: 110. —??146??— Slavia...

Kroó , Katalin

2009-01-01

188

Characterization of fold defects in AZ91D and AE42 magnesium alloy permanent mold castings  

Microsoft Academic Search

Casting premium-quality magnesium alloy components for aerospace and automotive applications poses unique challenges. Magnesium alloys are known to freeze rapidly prior to filling a casting cavity, resulting in misruns and cold shuts. In addition, melt oxidation, solute segregation and turbulent metal flow during casting contribute to the formation of fold defects. In this research, formation of fold defects in AZ91D

L. Bichler; C. Ravindran

2010-01-01

189

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

NASA Technical Reports Server (NTRS)

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.

Lang, H.; Baloga, S.

1999-01-01

190

Water Environment Federation. National TMDL Science and Policy Conference. Phoenix, AZ. November 13 16, 2002.  

E-print Network

Water Environment Federation. National TMDL Science and Policy Conference. Phoenix, AZ. November 13 ­ 16, 2002. AVAILABILITY OF ATMOSPHERICALLY DEPOSITED MERCURY TO RUNOFF AND RECEIVING WATERS Mark C to receiving waters; such estimates are overly conservative, and do not reflect the complex nature of mercury

Pitt, Robert E.

191

Structural evaluation of thermocouple probes for 241-AZ-101 waste tank  

SciTech Connect

This document reports on the structural analysis of the thermocouple probe to be installed in 241-AZ-101 waste tank. The thermocouple probe is analyzed for normal pump mixing operation and potential earthquake induced loads required by the Hanford Site Design Criteria SDC-4.1.

Kanjilal, S.K.

1994-12-06

192

Microstructure and properties of magnesium AZ31B–aluminum 7075 explosively welded composite plate  

Microsoft Academic Search

A composite plate of Mg alloy (AZ31B) and an Al alloy (7075) was fabricated by explosive welding. The microstructure and properties of the bonding interface after explosive cladding were investigated. The results show that the bonding interface had a wavy appearance with solidified melts in a regularly spaced pattern of discrete regions. Adiabatic shear bands and twin structure were found

Y. B. Yan; Z. W. Zhang; W. Shen; J. H. Wang; L. K. Zhang; B. A. Chin

2010-01-01

193

ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY IEEE LEOS Annual Meeting, Tucson, AZ, October 2003  

E-print Network

ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY IEEE LEOS Annual Meeting, Tucson, AZ Force #12;ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY IEEE LEOS Annual Meeting, Tucson Networks #12;ULTRAFAST OPTICS AND OPTICAL FIBER COMMUNICATIONS LABORATORY IEEE LEOS Annual Meeting, Tucson

Purdue University

194

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

SciTech Connect

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.

WERRY, S.M.

2000-03-23

195

78 FR 63869 - Change of Using Agency for Restricted Areas R-2309 and R-2312, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...of using agency for restricted areas R-2309 and R-2312 located in Arizona. The transfer...The Rule This action amends Title 14 Code of Federal Regulations (14 CFR) part...using agency name for Restricted Areas R-2309 Yuma, AZ, and R-2312...

2013-10-25

196

Subaru Telescope improved pointing accuracy in open-loop and Az rail flatness  

Microsoft Academic Search

The Subaru telescope had its astronomical first light in January 1999 and has been stably operated since the common use started in December 2000. The telescope is mounted on an alt-azimuth structure. The structure of 550 tons is supported by six hydrostatic oil pads which lift the structure by 50 microns. The azimuth (Az) and elevation (El) axes are driven

Satoru Negishi; Tomio Kanzawa; Daigo Tomono; Tomonori Usuda; Norio Ohshima; Kazuhito Namikawa; Takeji Ogasawara; Noboru Itoh

2006-01-01

197

Complete Genome Sequence of the Model Rhizosphere Strain Azospirillum brasilense Az39, Successfully Applied in Agriculture.  

PubMed

We present the complete genome sequence of Azospirillum brasilense Az39, isolated from wheat roots in the central region of Argentina and used as inoculant in extensive and intensive agriculture during the last four decades. The genome consists of 7.39 Mb, distributed in six replicons: one chromosome, three chromids, and two plasmids. PMID:25059863

Rivera, Diego; Revale, Santiago; Molina, Romina; Gualpa, José; Puente, Mariana; Maroniche, Guillermo; Paris, Gastón; Baker, David; Clavijo, Bernardo; McLay, Kirsten; Spaepen, Stijn; Perticari, Alejandro; Vazquez, Martín; Wisniewski-Dyé, Florence; Watkins, Chris; Martínez-Abarca, Francisco; Vanderleyden, Jos; Cassán, Fabricio

2014-01-01

198

Rapid coating of AZ31 magnesium alloy with calcium deficient hydroxyapatite using microwave energy.  

PubMed

Due to their unique biodegradability, magnesium alloys have been recognized as suitable metallic implant materials for degradable bone implants and bioresorbable cardiovascular stents. However, the extremely high degradation rate of magnesium alloys in physiological environment has restricted its practical application. This paper reports the use of a novel microwave assisted coating technology to improve the in vitro corrosion resistance and biocompatibility of Mg alloy AZ31. Results indicate that a dense calcium deficient hydroxyapatite (CDHA) layer was uniformly coated on a AZ31 substrate in less than 10min. Weight loss measurement and SEM were used to evaluate corrosion behaviors in vitro of coated samples and of non-coated samples. It was seen that CDHA coatings remarkably reduced the mass loss of AZ31 alloy after 7days of immersion in SBF. In addition, the prompt precipitation of bone-like apatite layer on the sample surface during immersion demonstrated a good bioactivity of the CDHA coatings. Proliferation of osteoblast cells was promoted in 5days of incubation, which indicated that the CDHA coatings could improve the cytocompatibility of the AZ31 alloy. All the results suggest that the CDHA coatings, serving as a protective layer, can enhance the corrosion resistance and biological response of magnesium alloys. Furthermore, this microwave assisted coating technology could be a promising method for rapid surface modification of biomedical materials. PMID:25686961

Ren, Yufu; Zhou, Huan; Nabiyouni, Maryam; Bhaduri, Sarit B

2015-04-01

199

Effect of Sb on the microstructure and mechanical properties of AZ91 magnesium alloy  

NASA Astrophysics Data System (ADS)

Effects of Sb addition on the microstructure, mechanical properties, and fracture behaviors of AZ91 magnesium alloy, as well as the sensitivity to section thickness of the structure and mechanical properties, have been studied. The results show that when Sb is added into the AZ91 alloy, the grain is refined, the Mg17Al12 phase is refined and granulated, and a new Mg3Sb2 phase is formed and becomes coarse needle-shaped as Sb content increases. The room-temperature tensile strength, elongation, and impact toughness increase first, and then decrease with increasing Sb content. The study on sensitivity to section thickness shows that, when composition is constant, the room-temperature tensile strength and elongation increase with the reduction of section thickness; when section thickness is constant, the room-temperature tensile strength and elongation increase first, and then decrease with increasing Sb content. Additionally, the Sb addition improves the tensile strength of the AZ91 alloy at 100°C and 150°C. The room-temperature tensile and impact fractographs of the AZ91 alloy show intergranular fracture. With increasing Sb content, the tearing deformation zones on the both fractographs enlarge at first, and then diminish, which is consistent with the change of tensile strength, elongation, and impact toughness increasing first, and then reducing with increasing Sb content.

Wang, Qudong; Chen, Wenzhou; Ding, Wenjiang; Zhu, Yanping; Mabuchi, M.

2001-03-01

200

Creep of a thixoformed and heat treated AZ91 Mg-Al-Zn alloy  

SciTech Connect

The most frequently used cast magnesium alloy is AZ91, which contains 9% Al, 1% Zn and some Mn. Recently some studies have investigated the creep response of AZ91 ingots, pressure-die-casting and thixoformed specimens; die-cast and thixoformed alloys frequently show a similar microstructure, with equiaxed grains of {alpha} phase (solid solution of Al and Zn in Mg) and a brittle secondary phase, Mg{sub 17}Al{sub 12} ({beta} phase), on grain boundaries. The die-cast alloy has a very fine grain size (15 {micro}m) and a higher concentration of Mg{sub 17}Al{sub 12} than ingots; the thixoformed alloy exhibits large {alpha} phase globules of around 100 {micro}m and small {alpha}-particles of few microns in the eutectic region. The creep response of the die-cast and thixoformed alloys was found to be substantially equivalent, the creep strength of the die-cast material being one order of magnitude lower than that of the ingot. Thixoforming is one of the new processes that can be used to produce Magnesium alloy components for automotive applications. However, the typical structure of the thixoformed AZ91 exhibits a modest ductility, a property that can be substantially improved by subsequent solution treatment aimed at dissolving the brittle {beta} phase. The present study was undertaken to investigate the high-temperature response of thixoformed and solution treated AZ91.

Spigarelli, S.

2000-01-31

201

78 FR 33703 - Safety Zone; Great Western Tube Float; Colorado River; Parker, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...sponsoring the Great Western Tube Float, which is held on the...river on inflatable rafts, inner tubes and floating platforms. The...further review under paragraph 34(g) of Figure 2-1 of the Commandant...T11-562 Safety zone; Great Western Tube Float; Parker, AZ. (a)...

2013-06-05

202

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

Federal Register 2010, 2011, 2012, 2013, 2014

...Employment and Training Administration [TA-W-70,654] DNS Electronics, Chandler, AZ; Notice of Termination of Investigation...filed on May 27, 2009, by three workers on behalf of workers of DNS Electronics, Chandler, Arizona. The petitioning group of...

2010-03-12

203

Mexico City, Mexico  

NASA Technical Reports Server (NTRS)

In this rare clear view of Mexico City, Mexico (19.5N, 99.0W), the network of broad avenues and plazas of the capital city are very evident. The city, built on the remnants of a lake in the caldera of a tremendous extinct volcano, is home to over twenty million people and is slowly sinking as subsidence takes it's toll on the lakebed.

1989-01-01

204

78 FR 60698 - Safety Zone, Lucas Oil Drag Boat Racing Series; Thompson Bay, Lake Havasu City, AZ.  

Federal Register 2010, 2011, 2012, 2013, 2014

...directed. (5) The Coast Guard may be assisted by other federal, state, or local agencies. Dated: September 10, 2013. S.M. Mahoney, Captain, U.S. Coast Guard, Captain of the Port San Diego. [FR Doc. 2013-23995 Filed...

2013-10-02

205

Acetylation of vertebrate H2A.Z and its effect on the structure of the nucleosome.  

PubMed

Purified histone H2A.Z from chicken erythrocytes and a sodium butyrate-treated chicken erythroleukemic cell line was used as a model system to identify the acetylation sites (K4, K7, K11, K13, and K15) and quantify their distribution in this vertebrate histone variant. To understand the role played by acetylation in the modulation of the H2A.Z nucleosome core particle (NCP) stability and conformation, an extensive analysis was conducted on NCPs reconstituted from acetylated forms of histones, including H2A.Z and recombinant H2A.Z (K/Q) acetylation mimic mutants. Although the overall global acetylation of core histones destabilizes the NCP, we found that H2A.Z stabilizes the NCP regardless of its state of acetylation. Interestingly and quite unexpectedly, we found that the change in NCP conformation induced by global histone acetylation is dependent on H2A/H2A.Z acetylation. This suggests that acetylated H2A variants act synergistically with the acetylated forms of the core histone complement to alter the particle conformation. Furthermore, the simultaneous occurrence of H2A.Z and H2A in heteromorphic NCPs that most likely occurs in vivo slightly destabilizes the NCP, but only in the presence of acetylation. PMID:19385636

Ishibashi, Toyotaka; Dryhurst, Deanna; Rose, Kristie L; Shabanowitz, Jeffrey; Hunt, Donald F; Ausió, Juan

2009-06-01

206

City of Cambridge: CityViewer  

NSDL National Science Digital Library

What is the best way to experience the city of Cambridge, Massachusetts? You could read a history of Harvard University, take a walking tour, or perhaps browse a topical website. But why not look at the Cambridge CityViewer for edification? This unique tool "allows the public to view, query, mark up, and print custom maps using only a web browser." Notedly, the viewer works best with Internet Explorer or Mozilla Firefox. Visitors can check out ten different topical overlays, including those dealing with city parks, construction projects, land parcels, sewers, zoning, and traffic. There are many ways to get started, such as performing a simple search, an advanced search, or even just by typing in a street name and number. For anyone with an interest in urban history, planning, and land use, this site is a rare treat.

207

Key functional regions in the histone variant H2A.Z C-terminal docking domain.  

PubMed

The incorporation of histone variants into nucleosomes represents one way of altering the chromatin structure to accommodate diverse functions. Histone variant H2A.Z has specific roles in gene regulation, heterochromatin boundary formation, and genomic integrity. The precise features required for H2A.Z to function and specify an identity different from canonical H2A remain to be fully explored. Analysis of the C-terminal docking domain of H2A.Z in Saccharomyces cerevisiae using epistatic miniarray profile (E-MAP) uncovered nuanced requirements of the H2A.Z C-terminal region for cell growth when additional genes were compromised. Moreover, the H2A.Z(1-114) truncation, lacking the last 20 amino acids of the protein, did not support regular H2A.Z functions, such as resistance to genotoxic stress, restriction of heterochromatin in its native context, GAL1 gene activation, and chromatin anchoring. The corresponding region of H2A could fully rescue the strong defects caused by loss of this functionally essential region in the C terminus of H2A.Z. Despite the dramatic reduction in function, the H2A.Z(1-114) truncation still bound the H2A.Z deposition complex SWR1-C, the histone chaperone Chz1, and histone H2B. These data are consistent with a model in which retaining the variant in chromatin after its deposition by SWR1-C is a crucial determinant of its function. PMID:21791612

Wang, Alice Y; Aristizabal, Maria J; Ryan, Colm; Krogan, Nevan J; Kobor, Michael S

2011-09-01

208

Key Functional Regions in the Histone Variant H2A.Z C-Terminal Docking Domain ?  

PubMed Central

The incorporation of histone variants into nucleosomes represents one way of altering the chromatin structure to accommodate diverse functions. Histone variant H2A.Z has specific roles in gene regulation, heterochromatin boundary formation, and genomic integrity. The precise features required for H2A.Z to function and specify an identity different from canonical H2A remain to be fully explored. Analysis of the C-terminal docking domain of H2A.Z in Saccharomyces cerevisiae using epistatic miniarray profile (E-MAP) uncovered nuanced requirements of the H2A.Z C-terminal region for cell growth when additional genes were compromised. Moreover, the H2A.Z(1–114) truncation, lacking the last 20 amino acids of the protein, did not support regular H2A.Z functions, such as resistance to genotoxic stress, restriction of heterochromatin in its native context, GAL1 gene activation, and chromatin anchoring. The corresponding region of H2A could fully rescue the strong defects caused by loss of this functionally essential region in the C terminus of H2A.Z. Despite the dramatic reduction in function, the H2A.Z(1–114) truncation still bound the H2A.Z deposition complex SWR1-C, the histone chaperone Chz1, and histone H2B. These data are consistent with a model in which retaining the variant in chromatin after its deposition by SWR1-C is a crucial determinant of its function. PMID:21791612

Wang, Alice Y.; Aristizabal, Maria J.; Ryan, Colm; Krogan, Nevan J.; Kobor, Michael S.

2011-01-01

209

Simultaneously enhanced tensile and compressive response of AZ31–NanoAl 2 O 3 –AA5052 macrocomposite  

Microsoft Academic Search

New bimetal AZ31–Al2O3\\/AA5052 macrocomposite comprising (a) Al2O3 nanoparticle-reinforced magnesium alloy AZ31 shell and (b) aluminum alloy AA5052 millimeter-scale core reinforcement was\\u000a fabricated using solidification processing followed by hot coextrusion. Microstructural characterization revealed more rounded\\u000a intermetallic particle of decreased size, reasonable Al2O3 nanoparticle distribution, and non-dominant (0 0 0 2) texture in the longitudinal and transverse directions in the AZ31–Al2O3 nanocomposite

M. Paramsothy; S. F. Hassan; N. Srikanth; M. Gupta

2009-01-01

210

Connecting the Fractal City  

Microsoft Academic Search

Living cities have intrinsically fractal properties, in common with all living systems. The pressure to accommodate both the automobile and increased population growth led twentieth-century urbanists to impose anti-fractal geometrical typologies. The fractal properties of the traditional city were erased, with disastrous consequences for the urban fabric. To undo this damage, it is necessary to understand several things in some

Nikos A. Salingaros

211

The Plains City Story  

ERIC Educational Resources Information Center

This case study portrays a contemporary phenomenon that affects many U.S. school districts. Specifically, the authors address the challenges that the superintendent of the Plains City school district faced as a result of a change in the demographic distribution of his district. The gradual development of the pig farming industry in Plains City…

van Olphen, Marcela; Rios, Francisco; Berube, William; Dexter, Robin; McCarthy, Robert

2006-01-01

212

Utah: Salt Lake City  

Atmospheric Science Data Center

... for the 2002 Winter Olympics, to be held in Salt Lake City, Utah. The mountains surrounding Salt Lake City are renowned for the dry, ... view. The Uinta Mountains contain the highest peaks in Utah and are notable as the most prominent east-west trending range in the ...

2014-05-15

213

Lost City News Release  

NSDL National Science Digital Library

This press release from the National Science Foundation provides an overview of the 2003 expedition to the Lost City Hydrothermal Field at the Atlantis Massif. It briefly describes the expedition, features of the Lost City, research results and implications for future discoveries. Photos and images accompany the text.

Affairs, Office O.; Foundation, National S.

214

Inequality and City Size*  

PubMed Central

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

Baum-Snow, Nathaniel; Pavan, Ronni

2013-01-01

215

H2A.Z landscapes and dual modifications in pluripotent and multipotent stem cells underlie complex genome regulatory functions  

E-print Network

Background: The histone variant H2A.Z has been implicated in nucleosome exchange, transcriptional activation and Polycomb repression. However, the relationships among these seemingly disparate functions remain obscure.

Ku, Manching

216

H2A.Z landscapes and dual modifications in pluripotent and multipotent stem cells underlie complex genome regulatory functions  

E-print Network

Abstract Background The histone variant H2A.Z has been implicated in nucleosome exchange, transcriptional activation and Polycomb repression. However, the relationships among these seemingly disparate functions remain ...

Ku, Manching

217

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

SciTech Connect

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).

WHITE, D.A.

1999-12-29

218

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

Federal Register 2010, 2011, 2012, 2013, 2014

...AZ; Application for Expansion; (New Magnet Site) Under Alternative Site Framework...c)) to include two additional new magnet sites in western Maricopa County, Arizona...current zone project includes the following magnet sites: Site 1 (230.25...

2012-12-19

219

The Social Ecology of Residential Land Management Complex Effects, Tradeoffs & Legacies in the Sonoran Desert of Phoenix, AZ  

E-print Network

in the Sonoran Desert of Phoenix, AZ Kelli Larson, Elizabeth Cook, Jaleila Brumand, Sharon Hall & Kimberly have risen in recent years. Water demands, chemical inputs, & changes in biodiversity are among

Hall, Sharon J.

220

Investigating the characteristics of AZ61 magnesium alloy on the hot and semi-solid compression test  

Microsoft Academic Search

The characteristics of magnesium AZ61 in semi-solid state have been investigated to understand the changes in its stress-strain\\u000a in the compression process, the effects on its strain under different processing temperatures, and the consequence of the\\u000a change of peak stress. First, the AZ61 magnesium alloy is heated to 660 C and sustained at that temperature for 5 min. Then\\u000a by natural cooling,

Jer-Liang Kuo; Sumio Sugiyama; Su-Hai Hsiang; Jun Yanagimoto

2006-01-01

221

Superplasticity and internal friction in microcrystalline AZ91 and ZK60 magnesium alloys processed by equal-channel angular pressing  

Microsoft Academic Search

Low-temperature superplasticity (LTSP) and internal friction in microcrystalline ZK60 and AZ91 magnesium alloys processed by equal-channel angular pressing (ECAP) are reported. Excellent low-temperature superplasticity (<300°C) was observed in ECAP-processed materials: elongations to failure are 810 and 570% in ZK60 and AZ91 alloys, respectively, at a strain rate of 3×10?3s?1. Internal friction can be practically used to determine the optimum temperature

V. N. Chuvil’deev; T. G. Nieh; M. Yu. Gryaznov; V. I. Kopylov; A. N. Sysoev

2004-01-01

222

The effect of texture and strain conditions on formability of cross-roll rolled AZ31 alloy  

Microsoft Academic Search

The effect of texture evolution of AZ31 Mg sheet on cross-roll rolling process has been investigated for the commercial AZ31 Mg sheet. The large ?23 was operated for the cross-roll rolled sample throughout the whole thickness, leading to the homogeneity of the (0002) basal texture. After recrystallization annealing at 673K for 30min, cross-roll rolled sample showed uniform texture intensity from

Dae-Guen Kim; Hyeon-Taek Son; Dae-Won Kim; Young-Ho Kim; Kye-Man Lee

2011-01-01

223

Effect of cooling rate on ignition point of AZ91D–0.98 wt.% Ce magnesium alloy  

Microsoft Academic Search

Influence of the cooling rate, Kp, on the ignition point of AZ91D–0.98 wt.% Ce magnesium alloy is investigated. To the AZ91D–0.98 wt.% Ce magnesium alloy, the cooling rate has a great effect on its microstructure and phase. XRD shows that it mainly consists of ?-Mg, Mg17Al12 and Ce phases with rapid solidification treatment, while ?-Mg, Mg17Al12 and Al11Ce3 phases are with air

W. Li; H. Zhou; W. Zhou; M. X. Wang

2007-01-01

224

Evaluation of AY/AZ tank farm ventilation system during aging waste retrieval operations  

SciTech Connect

Waste Management is currently planning to demonstrate mobilization of radioactive waste sludges in Tank 101-AZ beginning in October 1991. The retrieval system being designed will utilize mixer pumps that generate high-velocity, high-volume submerged liquid jets to mobilize settled solids. There is concern that these jets may also generate radioactive aerosols, some of which may be carried into the tank Ventilation system. The purpose of this study is to determine if the current AY/AZ ventilation system or the proposed ventilation system upgrade (Project W-030) will provide adequate deentrainment of liquid and solid aerosols during mixer pump operations, or if the radioactive aerosols will overload the HEPA filters.

Wong, J.J.; Waters, E.D.

1995-01-01

225

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

226

Mutations in Non-Acid Patch Residues Disrupt H2A.Z’s Association with Chromatin through Multiple Mechanisms  

PubMed Central

The incorporation of histone variants into nucleosomes is a critical mechanism for regulating essential DNA-templated processes and for establishing distinct chromatin architectures with specialised functions. H2A.Z is an evolutionarily conserved H2A variant that has diverse roles in transcriptional regulation, heterochromatin boundary definition, chromosome stability and DNA repair. The H2A.Z C-terminus diverges in sequence from canonical H2A and imparts unique functions to H2A.Z in the yeast S. cerevisiae. Although mediated in part through the acid patch-containing M6 region, many molecular determinants of this divergent structure-function relationship remain unclear. Here, by using an unbiased random mutagenesis screen of H2A.Z alleles, we identify point mutations in the C-terminus outside of the M6 region that disrupt the normal function of H2A.Z in response to cytotoxic stress. These functional defects correlate with reduced chromatin association, which we attribute to reduced physical stability within chromatin, but also to altered interactions with the SWR and INO80 chromatin remodeling complexes. Together with experimental data, computational modelling of these residue changes in the context of protein structure suggests the importance of C-terminal domain integrity and configuration for maintaining the level of H2A.Z in nucleosomes. PMID:24098487

Wood, Thomas J.; Thistlethwaite, Angela; Harris, Michael R.; Lovell, Simon C.; Millar, Catherine B.

2013-01-01

227

Electrochemical behavior of anodized Mg alloy AZ91D in chloride containing aqueous solution  

Microsoft Academic Search

Electrochemical behavior in aerated 3.5wt.% NaCl solution of Mg alloy AZ91D anodized or not has been investigated by using electrochemical impedance spectroscopy, potentiodynamic polarization and Ecorr–t curve. Their microstructures before and after corrosion have been examined under scanning electron microscope. Testing results from Ecorr–t and polarization curves indicate that the corrosion behavior of Mg alloy makes significant, characteristic changes due

Yongjun Zhang; Chuanwei Yan; Fuhui Wang; Wenfang Li

2005-01-01

228

Microstructures and dislocations in the stressed AZ91D magnesium alloys  

Microsoft Academic Search

The microstructures and the dislocation arrangements in the die cast AZ91D magnesium alloy as well as the stressed alloys have been investigated using transmission electron microscopy, high-resolution transmission electron microscopy and energy dispersive X-ray (EDX) analysis. Besides the dominant ?-Mg and ?-Mg17Al12 phases, Al8Mn5 and Mg5Al phases have also been found and studied in the alloy. Dislocation pile-ups have been

R. M Wang; A Eliezer; E Gutman

2003-01-01

229

Electroless nickel-plating on die cast magnesium alloy AZ91D  

Microsoft Academic Search

Electroless nickel-plating on die cast magnesium alloy AZ91D was investigated. Growth of the electroless nickel-plating coating was characterized using scanning electron microscopy. Corrosion resistance of the coating was evaluated by open circuit potential and potentiodynamic polarization curves in 3.5% (mass fraction) NaCl solution. The results show that plating deposition is initiated on the crevices and then spread onto primary ?

JIA Su-qiu; JIA Shu-sheng; YAO Jun

230

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting  

Microsoft Academic Search

The room temperature fatigue properties of AZ91 magnesium alloy produced by high pressure die casting (HPDC) as cast, heat treated, friction stir processed (FSP) and FSP and heat treated were studied. The fatigue properties of the material were evaluated for the HPDC magnesium alloy in the as-received state and after a solution treatment at 415 °C for 2 h and an ageing

P.. Cavaliere; P. P. De Marco

2007-01-01

231

Dissimilar friction stir welding between 5052 aluminum alloy and AZ31 magnesium alloy  

Microsoft Academic Search

Dissimilar friction stir welding between 5052 Al alloy and AZ31 Mg alloy with the plate thickness of 6 mm was investigated. Sound weld was obtained at rotation speed of 600 r\\/min and welding speed of 40 mm\\/min. Compared with the base materials, the microstructure of the stir zone is greatly refined. Complex flow pattern characterized by intercalation lamellae is formed

Yong YAN; Da-tong ZHANG; Cheng QIU; Wen ZHANG

2010-01-01

232

Cavitation characteristics in AZ31 Mg alloys during LTSP or HSRSP  

Microsoft Academic Search

The cavitation behaviors in heavily extruded fine-grained AZ31 Mg alloys loaded at 200–400 °C and 6×10?4–1×10?2 s?1 have been analyzed, covering the low temperature or high strain rate superplasticity (LTSP or HSRSP) regimes. Cavities smaller than 2 ?m are basically nearly spherical in shape and randomly dispersed in the matrix, suggesting the involvement of diffusion or superplasticity diffusion controlled cavity

C. J. Lee; J. C. Huang

2004-01-01

233

AzTEC 1.1 mm OBSERVATIONS OF THE MBM12 MOLECULAR CLOUD  

SciTech Connect

We present 1.1 mm observations of the dust continuum emission from the MBM12 high-latitude molecular cloud observed with the Astronomical Thermal Emission Camera (AzTEC) mounted on the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. We surveyed 6.34 deg{sup 2} centered on MBM12, making this the largest area that has ever been surveyed in this region with submillimeter and millimeter telescopes. Eight secure individual sources were detected with a signal-to-noise ratio of over 4.4. These eight AzTEC sources can be considered to be real astronomical objects compared to the other candidates based on calculations of the false detection rate. The distribution of the detected 1.1 mm sources or compact 1.1 mm peaks is spatially anti-correlated with that of the 100 {mu}m emission and the {sup 12}CO emission. We detected the 1.1 mm dust continuum emitting sources associated with two classical T Tauri stars, LkH{alpha}262 and LkH{alpha}264. Observations of spectral energy distributions (SEDs) indicate that LkH{alpha}262 is likely to be Class II (pre-main-sequence star), but there are also indications that it could be a late Class I (protostar). A flared disk and a bipolar cavity in the models of Class I sources lead to more complicated SEDs. From the present AzTEC observations of the MBM12 region, it appears that other sources detected with AzTEC are likely to be extragalactic and located behind MBM12. Some of these have radio counterparts and their star formation rates are derived from a fit of the SEDs to the photometric evolution of galaxies in which the effects of a dusty interstellar medium have been included.

Kim, M. J.; Kim, S.; Youn, S.; Kang, Y.-W. [Department of Astronomy and Space Science, Sejong University, KwangJin-gu, KunJa-dong 98, Seoul 143-747 (Korea, Republic of); Yun, M. S.; Wilson, G. W. [Department of Astronomy, University of Massachusetts, 710 North Pleasant St., Amherst, MA 01003 (United States); Aretxaga, I.; Hughes, D. H.; Humphrey, A. [Instituto Nacional de Astrofisca, Optica y Electronica, Tonantzintla, Puebla (Mexico); Williams, J. P. [Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, HI 96822 (United States); Austermann, J. E. [Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, Colorado 80309 (United States); Perera, T. A. [Department of Physics, Illinois Wesleyan University, Bloomington, IL 61701 (United States); Mauskopf, P. D. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Magnani, L., E-mail: sek@sejong.ac.kr [Department of Physics and Astronomy, The University of Georgia, Athens, GA 30602-2451 (United States)

2012-02-10

234

Mechanical properties and microstructure of gas tungsten arc welded magnesium AZ91D plates  

Microsoft Academic Search

Gas tungsten arc (GTA) welds were performed on 4-mm thick plates, machined from as-cast magnesium AZ91D ingots. The microstructure and defect formation was investigated by optical and scanning electron microscopy. Mechanical properties were determined by standard tensile tests on small-scale specimens. A wide heat affected zone (HAZ) (>3 mm) was created adjacent to the fusion line that consisted of two

A. Munitz; C. Cotler; A. Stern; G. Kohn

2001-01-01

235

Microstructure and mechanical properties of AZ80 magnesium alloy sheet processed by differential speed rolling  

Microsoft Academic Search

A heat-treatable AZ80 magnesium alloy has been subjected to differential speed rolling (DSR) at a large thickness reduction per pass of 33%, and microstructure, texture, mechanical properties, stretch formability as well as texture evolution during stretch forming have been investigated. The basal pole of the DSR-processed sheet tilts toward the rolling direction at 15°. The as-rolled sheet exhibits a combination

Xinsheng Huang; Kazutaka Suzuki; Naobumi Saito

2009-01-01

236

Effect of compression ratio on the microstructure evolution of semisolid AZ91D alloy  

Microsoft Academic Search

The effect of compression ratio on the microstructure evolution of semisolid AZ91D magnesium alloy manufactured by strain induced melt activation (SIMA) process was investigated. The specimens were compressed with different ratio at 230°C, and then were isothermal hold at the temperature of 560°C for 15min. During the compression process, as the increasing of compression ratios, the microstructures of samples changed

Q. Q. Zhang; Z. Y. Cao; Y. F. Zhang; G. H. Su; Y. B. Liu

2007-01-01

237

Test plan: Laboratory-scale testing of the first core sample from Tank 102-AZ  

SciTech Connect

The overall objectives of the Radioactive Process/Product Laboratory Testing (RPPLT), WBS 1.2.2.05.05, are to confirm that simulated HWVP feed and glass are representative of actual radioactive HWVP feed and glass and to provide radioactive leaching and glass composition data to WFQ. This study will provide data from one additional NCAW core sample (102-AZ Core 1) for these purposes.

Morrey, E.V.

1996-03-01

238

Improvements in the metallography of as-cast AZ91 alloy  

Microsoft Academic Search

Evaluation of the grain structure and grain size of cast magnesium–aluminum alloys is usually performed after grain-boundary-enhancing treatments which involve tedious heat treatment at high temperature. In this work, a rapid and simple etching method is described for metallographic preparation of AZ91 alloy, revealing grains without altering the as-cast dendritic microstructure and the presence of secondary phases. The etching reagent,

A Maltais; D Dubé; M Fiset; G Laroche; S Turgeon

2004-01-01

239

Characterization of ceramic PVD thin films on AZ31 magnesium alloys  

Microsoft Academic Search

Ceramic thin films have been widely used to protect the metal substrate as coatings in the past years. In order to improve the poor corrosion resistance of AZ31 magnesium alloy, the study in this paper used the electron beam evaporation method to prepare ceramic PVD films on its surface with TiO2 and Al2O3 as donors, respectively. Atomic force microscopy (AFM),

Guosong Wu; Xiaoqin Zeng; Wenbin Ding; Xingwu Guo; Shoushan Yao

2006-01-01

240

PVD Coating of Mg–AZ31 by Thin Layer of Al and Al–Si  

Microsoft Academic Search

Although magnesium alloys have the advantage of high specific strength, they have poor atmospheric corrosion resistance. An\\u000a important method of improving the corrosion resistance is by applying a coating layer. In this work, the physical vapor deposition\\u000a (PVD) technique is used for coating a magnesium (Mg) AZ31 sheet substrate with a thin layer of high purity aluminum (Al) and\\u000a Al–12.6%

Mohamed A. Taha; Nahed A. El-Mahallawy; Rawia M. Hammouda; Sherif I. Nassef

2010-01-01

241

SAFETY ANALYSIS FOR TANK 241-AZ-101 MIXER PUMP PROCESS TEST  

Microsoft Academic Search

This document contains the completed safety analysis which establishes the safety envelope for performing the mixer pump process test in Tank 241-AZ-101. This process test is described in TF-210-OTP-001. All equipment necessary for the mixer pump test has been installed by Project W-151. The purpose of this document is to describe and analyze the mixer pump test for Aging Waste

HAMMOND DM; HARRIS JP; MOUETTE P

1997-01-01

242

Light in the city  

E-print Network

This thesis focuses on enhancing the awareness of light for the pedestrian,and using light as a way of revealing the structure of the city and its relation to the cosmos. It proposes that aesthetic qualities of light inform ...

Srinivasan, Kavita, 1976-

2002-01-01

243

Sister Cities International  

NSDL National Science Digital Library

People from around the world have sought to establish links with other individuals from different nations, and since 1956, cities have sought to also establish meaningful relationships with other urban areas through the Sister Cities International organization. Currently, the organization represents more than 2,500 communities in 126 countries. Visitors to the site can learn which cities are currently seeking partnerships with other cities, read about the organization's annual conference, and also read about the programs they administer. Also, its calendar of events is quite full with programs designed for the general public, such as those dealing with relationships with countries in the Middle East and the question of local government. Finally, the material on the site is available in a number of different languages, including French, German, Spanish, and Japanese.

244

On Wearing the City  

Microsoft Academic Search

What would be the possible connection between dressing through the body and walking through the city? How could the space of architecture\\/ architexture be interwoven with literary narratives? This paper attempts to think through the \\

Hsiao-hung Chang

2006-01-01

245

Transforming Cities With Transit  

NSDL National Science Digital Library

How are cities transformed by the creation of new transit lines? How can existing transit lines be modified to create new land use opportunities for housing and commercial properties? These subjects are covered by a 172-page conference edition of a forthcoming paper from the World Bank. The paper was authored by Hiroaki Suzuki, Robert Cervero, and Kanako Iuchi. Visitors will note that the work focuses on "identifying barriers to and opportunities for effective coordination of transport infrastructure and urban development." The work takes on a number of global best practices of transit-oriented metropolises that have direct relevance to cities in developing countries and offers both analysis and suggestions for future projects. Sections here include "Lessons from Sustainable Transit-Oriented Cities," "Integrating Transit and Urban Development in Cities in the Developing World," and "Toward Sustainable Urban Futures."

Cervero, Robert.; Iuchi, Kanako; Suzuki, Hiroaki

246

Between house and city  

E-print Network

In an attempt to understand the relationships between a residential building type and the city, this thesis explores the quality of the urban context resulting from the assemblage of these buildings. The investigation takes ...

Kallus, Rachel Admati

1982-01-01

247

Exploring The Underground City.  

E-print Network

??The inception of Montreal’s underground displayed significant inventiveness in striving for a multi-level city, however today the urban network has developed into an overly-commercialized, perfunctory… (more)

Shaddick, Daniel

2010-01-01

248

Effects of Rare Earth Element Additions on the Impression Creep Behavior of AZ91 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The effects of 1, 2, and 3 wt pct rare earth (RE) element additions on the microstructure and creep behavior of cast AZ91 Mg alloy were investigated by impression tests. The tests were carried out under constant punching stress in the range 200 to 650 MPa at temperatures in the range 425 to 525 K. Analysis of the data showed that for all loads and temperatures, the AZ91-2RE alloy had the lowest creep rates and, thus, the highest creep resistance among all materials tested. This is attributed to the formation of Al11RE3 with a branched morphology, reduction in the volume fraction of the eutectic ?-Mg17Al12 phase, and solid solution hardening effects of Al in the Mg matrix. The stress exponents and activation energies were the same for all alloy systems studied, 5.3 to 6.5 and 90 to 120 kJ mol-1, respectively, with the exception that the activation energy for the AZ91-3RE system was 102 to 126 kJ mol-1. An observed decreasing trend of creep-activation energy with stress suggests that two parallel mechanisms of lattice and pipe diffusion-controlled dislocation climb are competing. Dislocation climb controlled by dislocation pipe diffusion is controlling at high stresses, whereas climb of edge dislocations is the controlling mechanism at low stresses.

Kabirian, F.; Mahmudi, R.

2009-09-01

249

The Cities Alliance  

NSDL National Science Digital Library

Sponsored by the World Bank and other organizations, the Cities Alliance is "a global coalition of cities and their development partners committed to scaling up successful approaches to poverty reduction." The "News" area is front and center on their homepage and it provides a fine overview of their work, which ranges from concerted efforts to upgrade slums in the developing world, developing strategies to help cities with their financial situation, and also working on cohesive and comprehensive development strategies. Visitors can click on the right-hand side of the page to learn more about each of these thematic areas in the "Cities Alliance Activities" section. Moving on, the "Publications" area with its annual reports, fact sheets, and archived e-newsletters is a place worth visiting as well. The site is rounded out by the "City Development Strategies" area, which offers a rigorous explanation of the ways in which cities can assess their existing strengths and what the key aspects of a meaningful development strategy might be.

250

The Right to the City  

Microsoft Academic Search

The identity and character of cities in America have been profoundly influenced by race. In the past, laws mandating the segregation of African American and white urban residents through racially discriminatory housing and lending policies created racial geographic boundaries within cities and between cities and suburbs. The impact of this racial segregation in cities can be seen in the creation

Ngai Pindell

2008-01-01

251

H2A.Z Acidic Patch Couples Chromatin Dynamics to Regulation of Gene Expression Programs during ESC Differentiation  

PubMed Central

The histone H2A variant H2A.Z is essential for embryonic development and for proper control of developmental gene expression programs in embryonic stem cells (ESCs). Divergent regions of amino acid sequence of H2A.Z likely determine its functional specialization compared to core histone H2A. For example, H2A.Z contains three divergent residues in the essential C-terminal acidic patch that reside on the surface of the histone octamer as an uninterrupted acidic patch domain; however, we know little about how these residues contribute to chromatin structure and function. Here, we show that the divergent amino acids Gly92, Asp97, and Ser98 in the H2A.Z C-terminal acidic patch (H2A.ZAP3) are critical for lineage commitment during ESC differentiation. H2A.Z is enriched at most H3K4me3 promoters in ESCs including poised, bivalent promoters that harbor both activating and repressive marks, H3K4me3 and H3K27me3 respectively. We found that while H2A.ZAP3 interacted with its deposition complex and displayed a highly similar distribution pattern compared to wild-type H2A.Z, its enrichment levels were reduced at target promoters. Further analysis revealed that H2A.ZAP3 was less tightly associated with chromatin, suggesting that the mutant is more dynamic. Notably, bivalent genes in H2A.ZAP3 ESCs displayed significant changes in expression compared to active genes. Moreover, bivalent genes in H2A.ZAP3 ESCs gained H3.3, a variant associated with higher nucleosome turnover, compared to wild-type H2A.Z. We next performed single cell imaging to measure H2A.Z dynamics. We found that H2A.ZAP3 displayed higher mobility in chromatin compared to wild-type H2A.Z by fluorescent recovery after photobleaching (FRAP). Moreover, ESCs treated with the transcriptional inhibitor flavopiridol resulted in a decrease in the H2A.ZAP3 mobile fraction and an increase in its occupancy at target genes indicating that the mutant can be properly incorporated into chromatin. Collectively, our work suggests that the divergent residues in the H2A.Z acidic patch comprise a unique domain that couples control of chromatin dynamics to the regulation of developmental gene expression patterns during lineage commitment. PMID:23990805

Subramanian, Vidya; Mazumder, Aprotim; Surface, Lauren E.; Butty, Vincent L.; Fields, Paul A.; Alwan, Allison; Torrey, Lillian; Thai, Kevin K.; Levine, Stuart S.; Bathe, Mark; Boyer, Laurie A.

2013-01-01

252

Antibiotic Attack (Kinetic City)  

NSDL National Science Digital Library

This game is a part of the Tau Pack of the Kinetic City site (see description below). In this simulation, the patient's bodies are filled with bacteria. The object is to cure as many patients as possible. Learning concepts enforced here are that antibiotics are specific for the type of bacteria they treat, their strength, and that the bacteria may also become resistant to the bacteria by mutations.KINETIC CITY DESCRIPTION: "Kinetic City" (www.kineticcity.com) is a fun, Web-based after-school science club for kids, ages 8 through 11. It combines exciting online animations and activities with boxes of hands-on science experiments. Children earn "Kinetic City" power points and collect stickers as they complete missions and learn standards-based science content. Here's how it works: The "Kinetic City" super crew (Keisha, Curtis, Megan and Max) needs the help of Earth kids to save their planet Vearth, from the science-distorting computer virus Deep Delete. Each of Deep Delete's 60 hideous strains attacks a different area of science with disastrous consequences. After each attack, teams of Earth kids fight back by viewing a short online animation describing the situation on Vearth; performing a series of activities to re-learn the lost science and going on a mission to Vearth during which they answer science questions and gobble up Deep Delete viruses. Their scores appear on their own Kinetic City Club Web page. "Kinetic City" is produced by the American Association for the Advancement of Science (AAAS), with a grant from the National Science Foundation. AAAS writes the "Project 2061 Benchmarks for Science Literacy," which forms the basis of most state science standards.

American Association for the Advancement of Science (;)

2005-01-01

253

Earth's City Lights  

NASA Technical Reports Server (NTRS)

This image of Earth's city lights was created with data from the Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS). Originally designed to view clouds by moonlight, the OLS is also used to map the locations of permanent lights on the Earth's surface. The brightest areas of the Earth are the most urbanized, but not necessarily the most populated. (Compare western Europe with China and India.) Cities tend to grow along coastlines and transportation networks. Even without the underlying map, the outlines of many continents would still be visible. The United States interstate highway system appears as a lattice connecting the brighter dots of city centers. In Russia, the Trans-Siberian railroad is a thin line stretching from Moscow through the center of Asia to Vladivostok. The Nile River, from the Aswan Dam to the Mediterranean Sea, is another bright thread through an otherwise dark region. Even more than 100 years after the invention of the electric light, some regions remain thinly populated and unlit. Antarctica is entirely dark. The interior jungles of Africa and South America are mostly dark, but lights are beginning to appear there. Deserts in Africa, Arabia, Australia, Mongolia, and the United States are poorly lit as well (except along the coast), along with the boreal forests of Canada and Russia, and the great mountains of the Himalaya. The Earth Observatory article Bright Lights, Big City describes how NASA scientists use city light data to map urbanization. Image by Craig Mayhew and Robert Simmon, NASA GSFC, based on DMSP data

2002-01-01

254

Directional Solidification of Mg-Al Alloys and Microsegregation Study of Mg Alloys AZ31 and AM50: Part II. Comparison between AZ31 and AM50  

NASA Astrophysics Data System (ADS)

Directional solidification (DS) of magnesium alloys AZ31 and AM50 was carried out to investigate microstructures and microsegregation under controlled solidification conditions. The methodology used is based on a customized DS technique elaborated on in Part I of this work. Dendritic microstructures observed in longitudinal sections of the quenched mushy zone, X-ray maps of fully directionally solidified cross sections, and quantitative solute profiles reveal the impact of cooling rate and alloy type. The solute-solvent correlation discloses the opposite segregation behavior of manganese compared to both aluminum and zinc and provides an impartial basis for the advanced weighted-interval ranking sort (WIRS) sorting scheme of electron probe microanalysis (EPMA) data. Precipitates Al8Mn5 and ?-Mg17Al12, predicted by thermodynamic calculations, are identified in the microstructure. The effect of back-diffusion during solidification, most pronounced for the component zinc, was clearly observed for both alloys in comparison with dedicated Scheil-total calculations.

Mirkovi?, Djordje; Schmid-Fetzer, Rainer

2009-04-01

255

The Atlantic Cities  

NSDL National Science Digital Library

What will the future of cities be like? It's a riveting question and one that excites the passions of the folks at The Atlantic Cities website. Their work here "explores the most innovative ideas and pressing issues facing today's global cities and neighborhoods." Visitors should browse through their newest articles, which might include "Why Our Kids Need Play" and "How Poverty Taxes the Brain." The site also has some neat features, including the Charts, Photos, and Urban Wonk areas. Geographers and artists will love the Maps section, which includes both scholarly and humorous offerings. First-time visitors should pay special attention here to "A Block-by-Block Map of Brooklyn, in Garbage" and "One Map, A World of Temperatures." Additionally, visitors can also sign up to receive their e-newsletter and other updates, including information about upcoming conferences and lectures sponsored by The Atlantic.

2013-09-23

256

The Guardian Cities  

NSDL National Science Digital Library

The Guardian newspaper has crafted this wonderful site to bring curious urbanologists news from Seoul to San Francisco. Supported in part by the Rockefeller Foundation, the site offers "a forum for debate and the sharing of ideas about the future of cities around the world.â Articles on the homepage might include pieces on investment in Detroit by Chinese corporations or the shifting public art scene in Glasgow. New visitors may wish to start with "An urbanist's tour of South Korea,â which features the musings of Colin Marshall on this dynamic Asian country. Moving along, the Global voices section features an interactive map of the best city blogs around the world. The site also contains the visually stimulating In pictures area and the up-to-the-moment Latest on cities newsfeed.

257

Engineers Week: Future City  

NSDL National Science Digital Library

The National Engineers Week Future City Competition provides âÂÂa fun and exciting educational engineering program for seventh- and eighth-grade students that combines a stimulating engineering challenge with a âÂÂhands-onâ application to present their vision of a city of the future.â The competition is intended to foster engineering skills, such as teamwork, communication and problem solving skills, as well as to inspire students to explore future careers in engineering. Using the commercial software SIMCITY to design their ideal city, students interact with each other, and with teachers and engineer mentors and also learn about the multi-disciplines within the engineering profession. The website has more information about the competition, as well as a handbook providing helpful tips and techniques. Examples of accomplishments from previous competitions are posted and CD-ROM video is available from regional coordinators to give more background on the competition.

258

Ultrafine particles in cities.  

PubMed

Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. PMID:24503484

Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

2014-05-01

259

Finding the Lost City  

NASA Technical Reports Server (NTRS)

Nicholas Clapp, a filmmaker and archeology enthusiast, had accumulated extensive information concerning Ubar, the fabled lost city of ancient Arabia. When he was unable to identify its exact location, however, he turned to the Jet Propulsion Laboratory (JPL) for assistance in applying orbital remote sensing techniques. JPL scientists searched NASA's shuttle imaging radar, as well as Landsat and SPOT images and discovered ancient caravan tracks. This enabled them to prepare a map of the trails, which converged at a place known as Ash Shisr. An expedition was formed, which found structures and artifacts from a city that predates previous area civilization by a thousand years. Although it will take time to validate the city as Ubar, the discovery is a monumental archeological triumph.

1993-01-01

260

100 Resilient Cities  

NSDL National Science Digital Library

The future of cities is the subject of much hand-wringing in urban policy circles. As of late, a popular topic has been the concept of urban "resilience" and the Rockefeller Foundation has taken this matter on with its 100 Resilient Cities initiative. On its website, first-time visitors should first explore the "What is Resilience?" area. Here, the topic is explained in detail and an infographic links to a number of helpful resources. Moving on, visitors can explore the foundation's blog and some of the Most Read entries, such as "The Five Fastest Growing Cities" and "Slumdog Urbanism." Each entry features a comments section that allows visitors to chime in with their own thoughts on resilience in the 21st century. The site is rounded out with a nice subscription feature, allowing readers the opportunity to receive email updates once new material is published on the site.

261

Inner city asthma.  

PubMed

The inner city has long been recognized as an area of high asthma morbidity and mortality. A wide range of factors interact to create this environment. These factors include well-recognized asthma risk factors that are not specific to the inner city, the structure and delivery of health care, the location and function of the urban environment, and social inequities. In this article, these facets are reviewed, and successful and unsuccessful interventions are discussed, to understand what is needed to solve this problem. PMID:25459579

Gergen, Peter J; Togias, Alkis

2015-02-01

262

State of the Cities  

NSDL National Science Digital Library

The report finds that while "the booming national economy and the growth of high-tech jobs have helped reverse decades of decline in America's cities," the "digital divide" continues to make itself felt as the number of high-tech jobs is growing 30 percent faster in the suburbs than urban areas. In addition, housing prices have risen at twice the rate of inflation, worsening an affordable housing shortage. See also the New Data section in this report for a review of the State of the Cities Data System, 2000.

2000-01-01

263

Low-Cycle Fatigue Behavior of Die-Cast Mg Alloys AZ91 and AM60  

NASA Astrophysics Data System (ADS)

The influence of microstructure and artificial aging response (T6) on the low-cycle fatigue behavior of super vacuum die-cast (SVDC) AZ91 and AM60 has been investigated. Fatigue lifetimes were determined from the total strain-controlled fatigue tests for strain amplitudes of 0.2 pct, 0.4 pct, 0.6 pct, 0.8 pct, and 1.0 pct under fully reversed loading at a frequency of 5 Hz. Cyclic stress-strain behavior was determined using an incremental step test (IST) and compared with the more traditional constant amplitude test. Two locations in a prototype casting were investigated to examine the role of microstructure and porosity on fatigue behavior. At all total strain amplitudes microstructure refinement had a negligible impact on fatigue life because of significant levels of porosity. AM60 showed an improvement in fatigue life at higher strain amplitudes when compared with AZ91 because of higher ductility. T6 heat treatment had no impact on fatigue life. Cyclic stress-strain behavior obtained via the incremental step test varied from constant amplitude test results due to load history effects. The constant amplitude test is believed to be the more accurate test method. In general, larger initiation pores led to shorter fatigue life. The fatigue life of AZ91 was more sensitive to initiation pore size and pore location than AM60 at the lowest tested strain amplitude of 0.2 pct. Fatigue crack paths did not favor any specific phase, interdentritic structure or eutectic structure. A multistage fatigue (MSF) model showed good correlation to the experimental strain-life results. The MSF model reinforced the dominant role of inclusion (pore) size on the scatter in fatigue life.

Rettberg, Luke H.; Jordon, J. Brian; Horstemeyer, Mark F.; Jones, J. Wayne

2012-07-01

264

Ultrasonic Examination of Double-Shell Tank 241-AZ-101. Examination Completed July 2007.  

SciTech Connect

AREVA NC Inc. (AREVA), under a contract from CH2M Hill Hanford Group (CH2M Hill), has performed an ultrasonic examination of selected portions of Double-Shell Tank 241-AZ-101. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The purpose of this examination was to provide information that could be used to evaluate the integrity of the wall of the primary tank. The requirements for the ultrasonic examination of Tank 241-AZ-101 were to detect, characterize (identify, size, and locate), and record measurements made of any wall thinning, pitting, or cracks that might be present in the wall of the primary tank. Any measurements that exceed the requirements set forth in the Engineering Task Plan (ETP), RPP-Plan-27202 (Jensen 2005) and summarized on page 1 of this document, are to be reported to CH2M HILL and the Pacific Northwest National Laboratory (PNNL) for further evaluation. Under the contract with CH2M HILL, all data is to be recorded on electronic media and paper copies of all measurements are provided to PNNL for third-party evaluation. PNNL is responsible for preparing a report(s) that describes the results of the AREVA ultrasonic examinations. The results of the examination of Tank 241-AZ-101 have been evaluated by PNNL personnel. The ultrasonic examination consisted of two vertical 15-in.-wide scan paths over the entire height of the tank and the heat-affected zone (HAZ) of five vertical welds and one horizontal weld from Riser 89. The examination also included two vertical 15-in.-wide scan paths over the entire height of the tank from Riser 90. The examination was performed to detect any wall thinning, pitting, or cracking in the primary tank wall.

Pardini, Allan F.; Weier, Dennis R.

2007-08-12

265

Clean Cities Natural Gas  

E-print Network

2014 Vehicle Buyer's Guide Clean Cities Natural Gas Propane Biodiesel Electric Hybrid Ethanol Flex . . . . . . . . . . . . . . . . . . . . . 15 Plug-In Hybrid Electric . . . . . . . . . . 18 Hybrid Electric vehicles, and hybrid luxury cars are now in the marketplace. Early in the 2013 calendar year the number

266

TELECOM-CITIES  

NSDL National Science Digital Library

TELECOM-CITIES, a discussion list sponsored by the Taub Urban Research Center at New York University, focuses on practical and theoretical aspects of the impacts of advanced telecommunications and telematics on urban centers. A web-based subscription form is available.

1997-01-01

267

Industrial Development in Cities  

Microsoft Academic Search

This paper uses data for eight manufacturing industries to test for and characterize dynamic production externalities in cities. The authors find evidence of both Marshall-Arrow-Romer (MAR) externalities, which are associated with past own industry employment concentration, and Jacobs externalities, which are associated with past diversity of local total employment. For mature capital goods industries, there is evidence of MAR externalities

Vernon Henderson; Ari Kuncoro; Matt Turner

1995-01-01

268

Hazards in the City  

NSDL National Science Digital Library

In this interactive activity adapted from the National Library of Medicine, explore the environmental hazards that might be found at various locations within cities and towns, including construction sites, factories, homes, hospitals, offices and stores, parks, restaurants, rivers and lakes, schools, and vehicles. A background essay, discussion questions, and standards correlations are also provided.

2010-10-04

269

Arthur Heights Baldwin City  

E-print Network

Aulory Badger Bala Baldwin City Barber Bartlett Basehor Bassett Bateham Batesville Baxter Springs Holcomb Holliday Hopkins Switch Hoxie Hughes Humboldt Hutchinson Independence Indian Ridge Indian Village Lafontaine Lake of the Forest Lake Quivira Lake Ridge Lake Shore Lake View Lakeland Estates Lakeside Acres

270

Nature in the City.  

ERIC Educational Resources Information Center

Describes a science program developed by the Cleveland Museum of Natural History, "Nature in the City," in which students and teachers learn together about the natural community surrounding their school. Includes program's rationale, list of "adventures," and methods. Discusses strategies of Sherlock Holmes'"adventure" focusing on animal tracks…

Ferbert, Mary Lou

1981-01-01

271

New City, New Challenges  

ERIC Educational Resources Information Center

After eight years at the helm of the City College of New York, where Dr. Gregory Williams grew enrollment at the minority-serving institution by 60 percent, instituted more rigorous admissions standards and launched the college's first capital campaign that raised more than $300 million, last fall he became the 27th president of the University of…

Matthews, Frank

2010-01-01

272

Visit Cell City  

NSDL National Science Digital Library

In this online activity, students search the Web in order to learn about human body cells. After collecting their research, they make an analogy between the structure of a human liver cell and a real city. Included are activity pages, team pages, teacher pages, and a list of electronic resources that students will need to complete the activity.

Glass, Sue

2007-12-12

273

Small city waterfront restoration  

Microsoft Academic Search

Redesign and reuse of waterfronts are a common experience today. Small cities presented with a deteriorating waterfront are faced with formidable economic and institutional impediments to their efforts to reverse the decline. This paper presents some design principles that if followed provide a framework for developing restoration plans. It also describes the efforts of the California State Coastal Conservancy to

Joseph Petrillo

1987-01-01

274

Study on the anodizing of AZ31 magnesium alloys in alkaline borate solutions  

NASA Astrophysics Data System (ADS)

A kind of environmentally friendly anodizing route for magnesium alloys, based on a new kind of organic additive (AA) contained traditional alkaline borate solution and 50 Hz civil ac current, has been studied. It is found that the formation of the anodic films is always coupled with the additive depended sparking and oxygen evolution, and the optimized ivory-white smooth anodic film possesses high corrosion resistance and excellent binding strength to AZ31 substrate. Meanwhile, The results also show that the structure, the corrosion resistance and the morphology of the anodic films are mainly dependent on the anodizing voltage, time and additives.

Wu, C. S.; Zhang, Z.; Cao, F. H.; Zhang, L. J.; Zhang, J. Q.; Cao, C. N.

2007-02-01

275

2008/9. november 17. Killts Roger Fenton az ELTE Egyetemi Knyvtrban felfedezett fotibl  

E-print Network

1 2008/9. ­ november 17. Kiållítås Roger Fenton az ELTE Egyetemi KÜnyvtårban felfedezett fotóiból Roger Fenton vilåghír, a 19. szåzadban Êlt angol fotogråfus ­ aki a brit kirålyi csalåd udvari. november 21. Ês 2009. januår 30. kÜzÜtt låtogatható, minden hÊtkÜznap 10 Ês 18 óra kÜzÜtt. Fenton volt

MĂźller, Viktor

276

Low temperature superplasticity in an AZ91 magnesium alloy processed by ECAE  

SciTech Connect

Magnesium alloys are especially suitable for use of the structural components in aerospace and outerspace applications due to their low density. In general, however, magnesium alloys have poor workability because of their h.c.p. structure. Therefore it is desirable to improve the poor workability, and superplastic forming is expected to be put into the processing in practical applications. In the present work, equal channel angular extrusion (ECAE), which allows one to attain high shear strain, has been conducted on an AZ91 magnesium alloy. The alloy processed by ECAE exhibited superplastic behavior at low temperatures of 448 and 473 K, which are about 0.5T{sub m}.

Mabuchi, M. [National Industrial Research Inst. of Nagoya (Japan)] [National Industrial Research Inst. of Nagoya (Japan); Iwasaki, H.; Yanase, K. [Himeji Inst. of Tech., Himeji, Hyogo (Japan)] [Himeji Inst. of Tech., Himeji, Hyogo (Japan); Higashi, K. [Osaka Prefecture Univ., Sakai, Osaka (Japan)] [Osaka Prefecture Univ., Sakai, Osaka (Japan)

1997-03-15

277

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

SciTech Connect

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.

CARLSON, A.B.

1998-11-19

278

Sinking coastal cities  

NASA Astrophysics Data System (ADS)

In many coastal and delta 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 sink below sea level. Land subsidence increases flood vulnerability (frequency, inundation depth and duration of floods), with floods causing major economic damage and loss of lives. In addition, differential land movement causes significant economic losses in the form of structural damage and high maintenance costs. This effects roads and transportation networks, hydraulic infrastructure - such as river embankments, sluice gates, flood barriers and pumping stations -, sewage systems, buildings and foundations. The total damage worldwide is estimated at billions of dollars annually. Excessive groundwater extraction after rapid urbanization and population growth is the main cause of severe land subsidence. In addition, coastal cities are often faced with larger natural subsidence, as they are built on thick sequences of soft soil. Because of ongoing urbanization and population growth in delta areas, in particular in coastal megacities, there is, and will be, more economic development in subsidence-prone areas. The impacts of subsidence are further exacerbated by extreme weather events (short term) and rising sea levels (long term).Consequently, detrimental impacts will increase in the near future, making it necessary to address subsidence related problems now. Subsidence is an issue that involves many policy fields, complex technical aspects and governance embedment. There is a need for an integrated approach in order to manage subsidence and to develop appropriate strategies and measures that are effective and efficient on both the short and long term. Urban (ground)water management, adaptive flood risk management and related spatial planning strategies are just examples of the options available. A major rethink is needed to deal with the 'hidden' but urgent threat of subsidence. As subsidence is spatially different and can be caused by multi processes, an assessment of subsidence in delta cities needs to answer questions such as: what are the main causes, how much is the current subsidence rate and what are future scenarios (and interaction with other major environmental issues), where are the vulnerable areas, what are the impacts and risks, how can adverse impacts can be mitigated or compensated for, and who is involved and responsible to act? In this study a quick-assessment of subsidence is performed on the following mega-cities: Jakarta, Ho Chi Minh City, Dhaka, New Orleans and Bangkok. Results of these case studies will be presented and compared, and a (generic) approach how to deal with subsidence in current and future subsidence-prone areas is provided.

Erkens, Gilles; Bucx, Tom; Dam, Rien; De Lange, Ger; Lambert, John

2014-05-01

279

Interfacial characteristics of squeeze-cast SiC reinforced AZ91D magnesium-based composites  

SciTech Connect

The method of producing magnesium-based composites with silicon carbide (SiC) particulates embedded in the matrix of magnesium AZ91D alloy by the squeeze-casting technique are described. This method involves the fabrication of a SiC particulate preform and the subsequent squeezing of molten magnesium into the preform. In this study, alumina, aluminum phosphate and a proprietary binder were used for the fabrication of SiC particulate preforms. The procedures employed in the fabrication of SiC/AZ91D composites are presented, together with the results of characterization of the composites using optical and transmission electron microscopy. Special attention is given to the reaction products in the bulk alloy and at the interfaces between SiC particles and the AZ91D matrix alloy.

Lo, J.; Carpenter, G.J.C.; Charest, M. [MTL/CANMET, Ottawa, Ontario (Canada)

1996-10-01

280

Bushehr as an Energic City  

NASA Astrophysics Data System (ADS)

Bushehr city is one of the famous city in the south of Iran which is situated in the coastal part of Persian Gulf. This paper try to discuss one of the most important theme which threat the sustainability and comfortability of tomorrow`s life. Changing Bushehr into an Energic city is one of the effective ways to solve the cities problem. For this purpose, we try to answer these questions: what is called as an energic city?; What are its main characteristics?; What are the aims of changing a city into an energic city? And what should be done to obtain the aims? For these purposes we offer a model which responds to the sustainability of Bushehr. This model uses 3 levels of activity that each level should respond to 5 significant characteristics of an energic city. For this purpose we present some applied ways in each category to obtain those characteristics.

Sabatsani, Nasser

281

77 FR 19610 - Marc Knapp, Inmate #-06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548; Order Denying...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Security Marc Knapp, Inmate --06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548; Order Denying Export Privileges...known address at: Inmate --06450-015, FCI Safford, P.O. Box 9000, Safford, AZ 85548, and when acting for or on...

2012-04-02

282

PROCLAMATION FLORIDA CITY GOVERNMENT WEEK  

Microsoft Academic Search

WHEREAS, city government is the government closest to most citizens, and the one with the most direct daily impact upon its residents; and WHEREAS, city government is administered for and by its citizens, and is dependent upon public commitment to and understanding of its many responsibilities; and WHEREAS, city government officials and employees share the responsibility to pass along their

Arthur C. Johnson; William G. Graham; Chairman Monroe Benaim; Sandra S. Richmond; L. Robinson

283

Dublin City University Educational Trust  

E-print Network

Dublin City University Educational Trust 2007 & 2008 RepoRt Established in 1988 by a group of business people, the mission of the Dublin City University Educational Trust is to build philanthropic relationships to advance the vision of Dublin City University. The DCU Educational Trust engages with friends

Humphrys, Mark

284

Rapid City, SD Showcase Streamgage  

USGS Multimedia Gallery

A USGS South Dakota Water Science Center streamgage was dedicated by Congressional and city officials on September 3 in Rapid City. This showcase streamgage is located on Rapid Creek at Rapid City in Founders Park and provides visitors with critical information about how streamflow is meas...

285

Genetic Services in Mexico City  

Microsoft Academic Search

In the year 2002, the population of Mexico was approaching 103 million inhabitants. Approximately 74% of them live in the cities with a continuous migration from rural to urban areas. Genetic departments are concentrated in the capital and other big cities. In this paper we review the current status of genetic departments in Mexico City, emphasizing the main areas of

Susana Kofman-Alfaro; Juan Carlos Zenteno

2004-01-01

286

Optimization of laser beam welding process parameters to attain maximum tensile strength in AZ31B magnesium alloy  

NASA Astrophysics Data System (ADS)

An empirical relationship is developed to predict tensile strength of the laser beam welded AZ31B magnesium alloy by incorporating process parameters such as laser power, welding speed and focal position. The experiments were conducted based on a three factor, three level, central composite face centered design matrix with full replications technique. The empirical relationship can be used to predict the tensile strength of laser beam welded AZ31B magnesium alloy joints at 95% confidence level. The results indicate that the welding speed has the greatest influence on tensile strength, followed by laser power and focal position.

Padmanaban, G.; Balasubramanian, V.

2010-11-01

287

CHARACTERIZATION AND FORMABILITY OF CONTINUOUS-CAST AZ31B MAGNESIUM ALLOY SHEETS  

SciTech Connect

The goal of this work is to understand the inter-relationship between the initial properties of continuous-cast magnesium alloy (AZ31B) sheets and their subsequent formability and post-formed mechanical performance for use in cost-effective, lightweight, automotive body panels. As-received sheets, provided by the Automotive Metals Division (AMD-602) team, were characterized by surface roughness measurements using mechanical profilometry. The arithmetic mean deviation of profile (Ra) and the maximum two-point height of profile (Ry) of the as-received sheets ranged from ~0.2-2 ?m and ~2-15 ?m, respectively. Several commercial lubricants were evaluated by thermal analysis and the liquid phase of the lubricants was found to evaporate/decompose upon heating leaving behind a solid residue upon heating to temperatures exceeding ~125-150°C. Elevated temperature bending-under-tension (BUT) friction tests were conducted at 350°C and the coefficient-of-friction values ranged from a minimum of ~0.1 (for tungsten disulfide lubricant) to ~0.7 when no lubricant was used. These results, in conjunction with those from the forming trials conducted by the AMD-602 team, will be eventually used to determine the role of sheet-die friction in determining the formability of AZ31B sheets.

Rohatgi, Aashish; Herling, Darrell R.; Nyberg, Eric A.

2009-09-24

288

Studies of the AZ91 magnesium alloy / SiO2-coated carbon fibres composite microstructure  

NASA Astrophysics Data System (ADS)

The microstructure of magnesium matrix composite reinforced with SiO2nano-layer coated carbon fibres, deposited by sol-gel method was characterized. The composite was obtained by infiltration method and the effect of SiO2 on the composite microstructure was analyzed by scanning electron microscopy combined with energy-dispersive X-ray spectroscopy (SEM+EDS) and transmission electron microscopy combined with energy-dispersive X-ray spectroscopy (TEM+EDS) methods. Good wettability of fibres by the magnesium alloy AZ91 (Al 9 wt%, Zn 0.3 wt%) was confirmed since fibres were closely surrounded with alloy and pulling-out effect was not visible. The interface region was evidently with aluminium enriched. Near carbon fibre surface a regular layer of SiOX oxide enriched with Al was detected by high angle annular dark field image (HAADF) combined with energy-dispersive X-ray spectroscopy (EDS). The plate or needle shaped very fine particles of Al12Mg17 were identified near the AZ91 matrix zone by bright field (BF) and selected area electron diffraction (SADP).

Olszówka-Myalska, A.; Botor-Probierz, A.

2010-02-01

289

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

USGS Publications Warehouse

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.

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

2010-01-01

290

Functional design criteria: Tank 101-AZ waste retrieval system. Revision 3  

SciTech Connect

Presented is the functional design criteria for equipment and subsystems required to test the mobilization of sludge in anticipation of retrieval of waste slurry from tank 241-AZ-101. The system utilizes jet forces from two high capacity pumps (mixer pumps) which recirculate liquid within the tank to mobilize the sludge and disperse it in the supernate and produce a slurry suitable for feed to the pretreatment process. This project provides the systems and equipment to prepare Tank AZ-101 for a functional test to verify sludge mobilization capabilities with use of mixer pumps. A retrieval functional test will be conducted by others (not part of the project) to confirm laboratory studies of waste mobilization characteristics and design parameters, to provide basis for system optimization for mobilization of other wastes, and to provide final verification of the effects of the retrieval process on wastes, and to provide final verification of the effects of the retrieval process on other tank farm operational parameters. No waste will be transferred from the tank during the FT. Prior to the test, some existing in-tank components must be removed and disposed of, and replaced with components with increased structural strength and rigidity. Special instrumentation will be provided to measure the effectiveness of the mixer pumps for sludge mobilization. Designing and providing equipment for component removal, handling, and solid waste disposal is a significant part of the project work scope

Manthei, M.E.

1995-07-01

291

Structural homogeneity and low-temperature micromechanical properties of ultrafine-grained AZ31 magnesium alloy  

NASA Astrophysics Data System (ADS)

The degree of microstructural homogeneity of ultrafine-grained (UFG) AZ31 magnesium alloy produced by a special thermomechanical process including four cycles of equal-channel angular pressing (ECAP, route Bc) is studied by the microindentation method. The defect structure of the UFG alloy is quite homogeneous. Texture owing to ECAP showed up as a lower average microhardness measured in a plane perpendicular to the extrusion axis than that measured in a plane containing that axis, and in a slight dependence of the microhardness on the location of the indent on the billet surface. The microhardness of the initial coarse-grained alloy is close to that of the UFG samples measured in a plane perpendicular to the extrusion axis. Tensile deformation of the samples over a wide temperature range of 4.2-295 K increased the microhardness in the region of the neck by more than 30%. The temperature dependence of the microhardness over 77-295 K is indicative of thermally activated plastic deformation in AZ31 alloy. The mechanism for deformation of the alloy appears to be interactions between dislocations and local defects of impurity origin.

Estrin, Y. Z.; Fomenko, L. S.; Lubenets, S. V.; Rusakova, A. V.

2011-06-01

292

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

NASA Astrophysics Data System (ADS)

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.

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

2013-11-01

293

Characterization of fold defects in AZ91D and AE42 magnesium alloy permanent mold castings  

SciTech Connect

Casting premium-quality magnesium alloy components for aerospace and automotive applications poses unique challenges. Magnesium alloys are known to freeze rapidly prior to filling a casting cavity, resulting in misruns and cold shuts. In addition, melt oxidation, solute segregation and turbulent metal flow during casting contribute to the formation of fold defects. In this research, formation of fold defects in AZ91D and AE42 magnesium alloys cast via the permanent mold casting process was investigated. Computer simulations of the casting process predicted the development of a turbulent metal flow in a critical casting region with abrupt geometrical transitions. SEM and light optical microscopy examinations revealed the presence of folds in this region for both alloys. However, each alloy exhibited a unique mechanism responsible for fold formation. In the AZ91D alloy, melt oxidation and velocity gradients in the critical casting region prevented fusion of merging metal front streams. In the AE42 alloy, limited solubility of rare-earth intermetallic compounds in the {alpha}-Mg phase resulted in segregation of Al{sub 2}RE particles at the leading edge of a metal front and created microstructural inhomogeneity across the fold.

Bichler, L. [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard St. E., Toronto, M5B 2K3 (Canada); Ravindran, C., E-mail: rravindr@ryerson.ca [Centre for Near-net-shape Processing of Materials, Ryerson University, 101 Gerrard St. E., Toronto, M5B 2K3 (Canada)

2010-03-15

294

Inverse Identification of the Dynamic Recrystallization Parameters for AZ31 Magnesium Alloy Using BP Neural Network  

NASA Astrophysics Data System (ADS)

The effect of the dynamic recrystallization (DRX) parameters are of prime importance to improve the accuracy of the numerical simulation of hot forming processes for metals. However, it is difficult to determine the values of DRX parameters from experiments because of the influence of various factors, such as temperature, etc. In the present study, the DRX parameters for AZ31 magnesium alloy are identified by using the method of inverse analysis based on measured stress, BP neural network algorithm, genetic algorithm (GA), orthogonal experiment, and numerical simulation. Then, by applying the identified parameters in finite element analysis, the comparison between the numerically calculated and the experimental results is made to verify the correctness of the method. The results show that the numerically calculated stress, strain, recrystallized fraction, and average grain size valus are in good agreement with the experimental ones. These results demonstrate that the method of inverse analysis is a feasible and an effective tool for determination of the AZ31 DRX parameters.

Lou, Yan; Wu, Wenhua; Li, Luoxing

2012-07-01

295

Identification of an advanced constitutive model of Magnesium alloy AZ31B  

NASA Astrophysics Data System (ADS)

The main aim of this paper is to study the flow behavior of the AZ31B magnesium alloy by means of tensile tests performed in extended ranges of temperature and strain rates. The flow stress-strain curves analyzed by power law type constitutive equation [1] can only fit well with experimental curves at the work-hardening stage. A new mathematical model is studied to describe the softening behavior of material based on tensile experiments. The relative parameters are obtained by fitting the equation with the experimental data. The genetic algorithm has been used to obtain the global optimal fitting parameters. The comparison between the fitted and experimental data proves the effectiveness of the model. The results indicate that this model leads to a better simulation of the flow stress during the softening stage than that of the power law equation. Based on this model, the deep drawing process has been simulated with the commercial finite element code FORGEŽ. The punch load and thickness distribution of AZ31 sheet have been studied. The study of the results is helpful to the application of the stamping technology for the magnesium alloy sheet.

Liu, Z. G.; Massoni, E.

2011-05-01

296

Project W-151 Tank 101-AZ Waste Retrieval System Year 2000 Compliance Assessment Project Plan  

SciTech Connect

This assessment describes the potential Year 2000 (Y2K) problems and describes the methods for achieving Y2K compliance for Project W-151, Tank 101-AZ Waste Retrieval System. The purpose of this assessment is to give an overview of the project. This document will not be updated and any dates contained in this document are estimates and may change. Two mixer pumps and instrumentation have been or are planned to be installed in waste tank 101-AZ to demonstrate solids mobilization. The information and experience gained during this process test will provide data for comparison with sludge mobilization prediction models and provide indication of the effects of mixer pump operation on an Aging Waste Facility tank. A limited description of system dates, functions, interfaces, potential Y2K problems, and date resolutions is presented. The project is presently on hold, and definitive design and procurement have been completed. This assessment will describe the methods, protocols, and practices to ensure that equipment and systems do not have Y2K problems.

BUSSELL, J.H.

1999-08-02

297

Research on microstructures of sub-rapidly solidified AZ61 Magnesium Alloy  

SciTech Connect

AZ61 magnesium alloy foils of 0.5-3.0 mm thick were successfully produced by using sub-rapid solidification technique. Microstructures of conventionally solidified (CS) and sub-rapidly solidified (sub-RS) alloys were examined by optical microscope (OM) and scanning electron microscope (SEM). The results showed that the cellular grain of 1.8-13.5 {mu}m can be obtained during sub-rapid solidification process. Phase compositions and microdistribution of the alloying elements in the foils were analyzed by X-ray diffraction (XRD) and electron probe microanalyzer (EPMA), respectively. The eutectic transformation L {yields} {alpha}-Mg + {beta}-Mg{sub 17}Al{sub 12} and microsegregation in conventionally solidified AZ61 alloy were remarkably suppressed in sub-rapid solidification process. As a consequence, the alloying elements Al, Zn, Mn showed much higher solid solubility and the sub-rapid solidification microstructures dominantly consisted of supersaturated {alpha}-Mg solid solution. Meanwhile, the {beta}-Mg{sub 17}Al{sub 12} phases located in the {alpha}-Mg grain boundaries are largely decreased due to high solidification cooling rate.

Teng Haitao, E-mail: seantht@yahoo.com.cna [Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Ministry of Education (China); School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Zhang Xiaoli; Zhang Zhongtao [Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Ministry of Education (China); School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Li Tingju, E-mail: tjuli@dlut.edu.cn [Key Laboratory for Materials Modification by Laser, Ion and Electron Beams, Ministry of Education (China); School of Materials Science and Engineering, Dalian University of Technology, Dalian 116085 (China); Cockcroft, Steve [Department of Materials Engineering, University of British Columbia, Vancouver (Canada)

2009-06-15

298

Corrosion behavior of magnesium alloy AZ91 and its MMC in NaCl solution  

SciTech Connect

The corrosion behaviors of magnesium alloy AZ91C and its Al{sub 2}O{sub 3}(short fiber)-reinforced metal matrix composite (MMC) in alkaline solutions (pH 10.5) containing chloride were compared using potentiodynamic polarization measurements, electrochemical impedance spectroscopy (EIS) and immersion tests. Dependence of polarization characteristics (corrosion potential and corrosion current density) on chloride concentration was similar for both materials. The corrosion potential E{sub corr} decreased linearly with the logarithm of chloride concentration, while the corrosion current density i{sub corr} increased rapidly at chloride concentrations larger than 0.1%, with the i{sub corr} for the MMC consistently higher than that for AZ91C, reaching a factor of about 3 in3.5% sodium chloride solution. EIS data indicated that the protective film on the MMC was inferior to that on the matrix alloy. With stirring and at frequencies higher than 5 Hz, the electrode/electrolyte interface might be described by the simplified Randles model for both materials. Immersion tests showed that the corrosion rate of the MMC, in terms of weight loss, was about 7 times that of the matrix alloy. Thus the present investigation indicated that in alkaline solutions containing chloride ions, the presence of Al{sub 2}O{sub 3} short fibers in the alloy did not drastically alter the corrosion behavior, but significantly reduced its corrosion resistance.

Chan, W.M.; Cheng, F.T.; Leung, L.K.; Horylev, R.J.; Yue, T.M. [Hong Kong Polytechnic Univ., Hunghom (Hong Kong)

1997-12-01

299

Characterization of AZ31B wrought magnesium alloy joints welded by high power fiber laser  

SciTech Connect

A 6 kW fiber laser is used to weld AZ31B wrought magnesium alloy and the characterization of welded joints are studied by the observations of bead size, microstructure and mechanical properties. The accepted joints without macro-defects can be obtained when the laser power is in the range of 2.5 to 4.0 kW. Typical hexagonal dendrites are observed in the fusion zone, whose average semi-axis length increases with increasing heat input or decreasing welding speed. The minimum ultimate tensile strength of welded joints reaches 227 MPa, 94.6% of the base metal. And when the heat input reduces to 48 J/mm or lower, the joints are fractured in the base metal, showing stronger failure strength compared to the base metal. For the joints ruptured in the weld metal, the fracture surface is characterized by a ductile-brittle mixed pattern consisting of both dimples and cleavages. Finally, the formation mechanism of pore in the welds is discussed and summarized by the pore morphologies on the fracture surface. - Highlights: {yields} Accepted joints of AZ31B Mg alloy are produced by high power fiber laser. {yields} Optimal welding parameters are summarized by experimental observations. {yields} Obvious hexagonal dendrites are observed in the fusion zone. {yields} The joints are stronger than base metal as the heat input is lower than 48 J/mm. {yields} Pore formation mechanism of welded joints is discussed and summarized.

Wang Zemin; Gao Ming, E-mail: mgao@mail.hust.edu.cn; Tang Haiguo; Zeng Xiaoyan

2011-10-15

300

Low-Power Laser/Arc Hybrid Welding Behavior in AZ-Based Mg Alloys  

NASA Astrophysics Data System (ADS)

The low-power laser/arc hybrid welding behaviors of the AZ-based Mg alloys in similar and dissimilar joints are examined in this study in terms of welding parameters, fusion-zone characteristics, mechanical properties, welding temperature fields, and laser-induced arc plasma/plume. Experiments were conducted using a low-power (300 W) pulsed Nd:YAG laser with a gas tungsten welding arc. The results show that the AZ-based Mg alloys can be easily welded by laser/arc hybrid welding process. The introduction of low-power laser beam can stabilize the welding arc even at a high-speed welding, and spattering behavior of laser welding disappeared due to the introduction of welding arc. With the increases of arc power, a higher weld depth can be obtained, and the weld depths for laser and arc acting in combination (laser/arc) are 2 times higher than those of for laser and arc acting separately (laser + arc) in optimal conditions. The postweld tensile strength of Mg alloys could recover ˜80 to 100 pct of the original strength in similar or dissimilar joints. The fatigue strength in laser/arc hybrid welded specimens is equal to that of the unweld base metal.

Liu, L. M.; Song, G.; Zhu, M. L.

2008-07-01

301

Fatigue properties of magnesium alloy AZ91 processed by severe plastic deformation.  

PubMed

Fatigue properties of cast AZ91 magnesium alloy processed by severe plastic deformation were investigated and compared with the properties of the initial cast state. The severe plastic deformation was carried out by equal channel angular pressing (ECAP). The ECAP treatment resulted in a bimodal structure. The bimodality consists in a coexistence of fine grained areas with higher content of Mg17Al12 particles and areas exhibiting larger grains and lower density of Mg17Al12 particles. Improvement of the basic mechanical properties of AZ91 (yield stress, tensile strength and ductility) by ECAP was significant. Also the improvement of the fatigue life in the low-cycle fatigue region was substantial. However the improvement of the fatigue strength in the high-cycle fatigue region was found to be negligible. The endurance limit based on 10(7) cycles for the cast alloy was 80MPa and for the alloy processed by ECAP 85MPa. The cyclic plastic response in both states was qualitatively similar; initial softening was followed by a long cyclic hardening. Fatigue cracks in cast alloy initiate in cyclic slip bands which were formed in areas of solid solution. In the case of severe plastic deformed material with bimodal structure two substantially different mechanisms of crack initiation were observed. Crack initiation in slip bands was a preferred process in the areas with large grains whereas the grain boundaries cracking was a characteristic mechanism in the fine grained regions. PMID:25498295

Fintová, Stanislava; Kunz, Ludvík

2015-02-01

302

Effects of heat input on microstructure and tensile properties of laser welded magnesium alloy AZ31  

SciTech Connect

A 3 kW CO{sub 2} laser beam was used to join wrought magnesium alloy AZ31 sheets, and the effects of heat input on the quality of butt welding joints were studied. By macro and microanalysis, it is found that the welding heat input plays an important role in laser welding process for AZ31 wrought sheets. After welding, the grains far from the weld centre present the typical rolled structure. But the microstructure out of the fusion zone gradually changes to complete equiaxed crystals as the distance from the weld centre decreases. Adjacent to the fusion boundary, there is a band region with columnar grains, and its growth direction is obviously perpendicular to the solid/liquid line. The microstructure in fusion centre consists of fine equiaxed grains and the many precipitated particles are brittle phase Mg{sub 17}Al{sub 12} or Mg{sub 17}(Al,Zn){sub 12}. With increasing the heat input, the band width of columnar grains varies, the grains in fusion zone get coarser, and the distribution of precipitates changes from intragranularly scattered particles to intergranularly packed ones. The results of tensile test show that the change trend of ultimate tensile strength (UTS) and elongation of the welded joints is to increase at first and then decrease with the heat input increasing. When the heat input reaches 24 J mm{sup -1}, the maximum value of the UTS is up to 96.8% of the base metal.

Quan, Y.J. [School of Materials Science and Engineering, Hunan University, Changsha 410082 (China)], E-mail: quanyj_2006@yahoo.com.cn; Chen, Z.H.; Gong, X.S.; Yu, Z.H. [School of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

2008-10-15

303

Where Are the Cities?  

NSDL National Science Digital Library

This investigation requires students to locate several major U.S. cities using four different sources: an outline map, a nighttime lights image, an atlas map, and a space shuttle image. After analyzing and comparing the information from those sources, students will offer explanations for establishing cities in particular locations. The URL opens to the investigation directory, with links to teacher and student materials, lesson extensions, resources, teaching tips, and assessment strategies. This is Investigation 4 of four found in the Grades K-4 Module 3 of Mission Geography. The Mission Geography curriculum integrates data and images from NASA missions with the National Geography Standards. Each of the four investigations in Module 3, while related, can be done independently. Please see Investigation 1 of this module for a two-page module overview and list of all standards addressed.

304

Exploring small city maps.  

PubMed

The exploration of city maps has exploded recently due to the wide availability, increasing use of, and reliance on small positioning and navigational devices for personal use. In this study, subjects explored small, 3-mile diameter circular maps exemplifying five different types of street networks common in the United States, in order to locate a hypothetical city hall. Chosen locations indicated that subjects are able to identify more accessible sites. Monitoring eye position revealed that women explored maps faster, using more widely dispersed but more narrowly focused gaze clusters than men. The type of street network influenced the time spent by the eyes in a locale and differentially affected the size of gaze clusters between women and men, underscoring the complex interactions of gender-specific strategies with street network types. PMID:22990289

Christova, Peka; Scoppa, Martin; Peponis, John; Georgopoulos, Apostolos P

2012-11-01

305

City of Chicago Landmarks  

NSDL National Science Digital Library

The city of Chicago has many hundreds of wonderful architectural landmarks and this helpful website is a great resource for anyone with an interest in such matters. On the site, visitors can start by checking out the Landmarks Tours to get started. There over a dozen tours here, including Mansions Tour, Art Deco Tour, and Pre-Fire Chicago Tour. Moving on, visitors may also wish to look over the Architects area. Here they will encounter some of the usual suspects (Frank Lloyd Wright, Louis Sullivan, etc.) and learn about some lesser-known architects, such as Solon S. Beman and William W. Boyington, who designed the wonderful entrance to Rosehill Cemetery. The Style Guide offers a great primer for those who'd like to know more about two dozen architectural styles, including Craftsman, International, and Tudor Revival. Finally, the site also includes a Listings area, complete with information about all of the buildings on the city's official landmarks list.

306

Freedomship: City At Sea  

NSDL National Science Digital Library

Freedomship is an enormous floating city that will be a monument to engineering skill and ingenuity. It will serve as a vacation resort or even a home for people with enough money. Although still in the pre-construction phase of the project, the Web site offers a good deal of information about the ship's design. It will be almost a mile long and rise 25 stories above the water. The ship will accommodate around 40,000 visitors who can arrive by boat or plane (yes, there will even be a small airport on the top deck). When Freedomship is not moving, it will sit offshore near major cities and other popular tourist destinations. The Web site provides several artist renderings that tantalize the imagination. Freedomship will be featured on Engineering the Impossible on the Discovery Channel February 25th, 2002.

2002-01-01

307

Vatican City State  

NSDL National Science Digital Library

On February 11, 1929 the Vatican City State was inaugurated with the signing of the Lateran Accords. With its motto, "A small territory with a great mission", the State is celebrating its 80th anniversary with a number of celebrations this year. This very fine site brings together a veritable cornucopia of information about the Vatican City State, including information about its governance structure, monuments, and philatelic culture. Visitors can start their journey by looking at webcams that provide a top-notch view of St. Peter's Square and the Governorate Palace. Moving on, visitors can also click on the "History" section to learn about the long history of the Vatican, and how the term has been used over the millennia. Visitors can also listen in to Vatican Radio, and check up on official news releases from the Vatican Information Service.

308

Raptors in the City  

NSDL National Science Digital Library

This new Web site from the nonprofit educational program Raptors in the City was developed to enhance inner city kids' use of technology and connection with nature. Appropriate for all types of students, the site focuses on the Peregrine Falcon, a species previously on the brink of extinction, but, through population recovery efforts on many downtown skyscrapers, has become an endangered species success story. Students are able to navigate through the entire 2002 courtship and nesting story of a pair of falcons nesting on a skyscraper in Cleveland, Ohio, and view images of the birds in their nest. Additionally, the site includes a link to a live falcon cam and describes additional educational curricula that can be purchased from Mindfull Publishing.

309

Lost City Expedition  

NSDL National Science Digital Library

This website provides an account of a research cruise to the Lost City Hydrothermal Field at the summit of the Atlantis Massif. During this 32-day expedition, scientists onboard the research vessel Atlantis explored active limestone chimneys that rise 200 feet above the seafloor. This site features information about the biology, chemistry and geology of the Lost City area, as well as explanations of the instruments used to sample and analyze these parameters. It also describes how researchers used the robotic Autonomous Benthic Vehicle and three-person submarine Alvin to explore, map and sample the sea floor. The site also includes a daily shipboard journal, a glossary, and an ask-a-scientist online form. This extensive site provides in-depth, broadly accessible information about the science, mapping and operations of this expedition and hydrothermal systems in general.

University of Washington

310

Muncie City Improvement Resolutions  

NSDL National Science Digital Library

Municipal improvement resolutions may not be everyone's cup of tea, but this digital collection should win over skeptics of all sorts. The people at Ball State University's Digital Media Repository have digitized over 1,000 items. The records include city ordinances, resolutions, and other materials from the City Clerk's office in Muncie, Indiana. Their creation dates range from 1892 to 1922 and their subjects include street, alley, sidewalk, and sewer improvements in the area. The archive is a very compelling look into urban development as it shows an increased interest (and at times, resistance) to all sorts of improvements from property owners, local businesspeople, and elected officials during this dynamic period in Muncie's history. Visitors can look over the Recent Additions area or perform a specific search. [KMG

311

Elevated temperature mechanical properties and microstructures of high pressure die cast magnesium AZ91 alloy cast with different section thicknesses  

Microsoft Academic Search

This paper investigates the influence of variations in the microstructure of high pressure die cast AZ91 on the elevated temperature mechanical properties of the alloy. Thinner-walled high pressure die castings show an improvement in elevated temperature strength, ductility and creep resistance. Further improvements to the creep resistance were achieved by ageing the alloy prior to creep testing. It appears that

M. S. Dargusch; M. A. Easton; S. M. Zhu; G. Wang

2009-01-01

312

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...

313

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 ...

314

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...

315

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...

316

Home TV Radio Talk Where I Live A-Z Index Low Graphics version | Change edition About BBC News  

E-print Network

Home TV Radio Talk Where I Live A-Z Index Low Graphics version | Change edition About BBC News News and Signal Processing at the By Roberto Belo BBC News technology reporter University of Surrey's Jeremiah Tesco begins m EU confident ov Page 1 of 4BBC NEWS | Technology | Putting a face to 'Big Brother' 08

Bowden, Richard

317

Pump Jet Mixing and Pipeline Transfer Assessment for High-Activity Radioactive Wastes in Hanford Tank 241-AZ-102  

SciTech Connect

The authors evaluated how well two 300-hp mixer pumps would mix solid and liquid radioactive wastes stored in Hanford double-shell Tank 241-AZ-102 (AZ-102) and confirmed the adequacy of a three-inch (7.6-cm) pipeline system to transfer the resulting mixed waste slurry to the AP Tank Farm and a planned waste treatment (vitrification) plant on the Hanford Site. Tank AZ-102 contains 854,000 gallons (3,230 m{sup 3}) of supernatant liquid and 95,000 gallons (360 m{sup 3}) of sludge made up of aging waste (or neutralized current acid waste). The study comprises three assessments: waste chemistry, pump jet mixing, and pipeline transfer. The waste chemical modeling assessment indicates that the sludge, consisting of the solids and interstitial solution, and the supernatant liquid are basically in an equilibrium condition. Thus, pump jet mixing would not cause much solids precipitation and dissolution, only 1.5% or less of the total AZ-102 sludge. The pump jet mixing modeling indicates that two 300-hp mixer pumps would mobilize up to about 23 ft (7.0 m) of the sludge nearest the pump but would not erode the waste within seven inches (0.18 m) of the tank bottom. This results in about half of the sludge being uniformly mixed in the tank and the other half being unmixed (not eroded) at the tank bottom.

Y Onishi; KP Recknagle; BE Wells

2000-08-09

318

Evaluation of waste temperatures in AWF tanks for bypass mode operation of the 702-AZ ventilation system, Project W-030  

Microsoft Academic Search

This report describes the results of thermal hydraulic analysis performed to provide data in support of Project W-030 to startup new 702-AZ Primary Ventilation System. During the startup of W-030 system, the ventilation system will be operating in bypass mode. In bypass made of operation, the system is capable of supplying 1000 cfm total flow for all four AWF doubleshell

Sathyanarayana

1997-01-01

319

WM'05 Conference, February 27 March 3, 2005, Tucson, AZ WM-5278 IDENTIFYING RADIOACTIVE SOURCES AT THE DEMOLITION SITE  

E-print Network

Portal Monitor at entrance to scrap yard #12;WM'05 Conference, February 27 ­ March 3, 2005, Tucson, AZ WM processing sites, some facilities have voluntarily installed radiation monitoring devices at the entrance the demolition industry secure radioactive gauges and devices at their point of installation. Figure 1 Radiation

320

76 FR 81525 - Notice of Realty Action: Conveyance of Federally Owned Mineral Interests in Pinal County, AZ  

Federal Register 2010, 2011, 2012, 2013, 2014

...Action: Conveyance of Federally Owned Mineral Interests in Pinal County, AZ AGENCY...the conveyance of the federally owned mineral interests of a 459.60 acre tract of...notice temporarily segregates the Federal mineral interests in the land covered by the...

2011-12-28

321

Modeling texture evolution during rolling process of AZ31 magnesium alloy with elasto-plastic self consistent model  

Microsoft Academic Search

To gain a better understanding about texture evolution during rolling process of AZ31 alloy, polycrystalline plasticity model was implemented into the explicit FE package, ABAQUS\\/Explicit by writing a user subroutine VUMAT. For each individual grain in the polycrystalline aggregate, the rate dependent model was adopted to calculate the plastic shear strain increment in combination with the Voce hardening law to

Shi-yao HUANG; Shao-rui ZHANG; Da-yong LI; Ying-hong PENG

2011-01-01

322

A Crystalline Plasticity Finite Element Method for Simulation of the Plastic Deformation of AZ31 Magnesium Alloys  

Microsoft Academic Search

In this paper, a constitutive framework based on a crystalline plasticity model is employed to simulate the plastic deformation of AZ31 magnesium alloy, which posses the hexagonal close packed (HCP) crystal structure. Dislocation slip and mechanical twinning are taken into account in the model. The successive integration method is used to determine the active slip systems, and the contribution of

Dayong Li; Shaorui Zhang; Weiqin Tang; Shiyao Huang; Yinghong Peng

2010-01-01

323

Effects of humidity and contact material on fretting fatigue behavior of an extruded AZ61 magnesium alloy  

Microsoft Academic Search

Fretting fatigue tests of the extruded AZ61 magnesium alloy with the same contact material under low and high humidity were carried out to investigate basic fretting fatigue characteristics and effect of humidity on fretting fatigue behavior. Influence of contact material was also studied by using JIS S45C carbon steel contact material. Degradation of fatigue strength due to fretting was much

Anchalee Saengsai; Yukio Miyashita; Yoshiharu Mutoh

2009-01-01

324

Resistance spot weld fatigue behavior and dislocation substructures in two different heats of AZ31 magnesium alloy  

Microsoft Academic Search

Fatigue life and dislocation substructure were evaluated in two groups of AZ31 Mg alloy resistance spot welds (heats SA and SB respectively, which had similar chemical compositions but different fusion zone microstructures). The results showed that the SA welds with a refined microstructure displayed a higher fatigue resistance than the SB welds when tested under conditions of higher cyclic load

L. Xiao; L. Liu; D. L. Chen; S. Esmaeili; Y. Zhou

2011-01-01

325

Weldability of A7075-T651 and AZ31B dissimilar alloys by MIG welding method based on welding appearances  

NASA Astrophysics Data System (ADS)

It is not recommended to weld aluminium and magnesium dissimilar alloys using fusion welding method because of the formation of AlmMgn type intermetallic brittle compounds like Mg2Al3, Mg17Al12 etc. in the welding joint. These brittle compounds deteriorate the mechanical properties of the joint. But so far, insufficient researches have been attempted to stop the formation of AlmMgn type intermetallic brittle compounds in fusion welding method. The aim of this research work was to investigate on the weldability between A7075-T651 and AZ31B dissimilar alloys based on welding appearances and study the formation of intermetallic brittle compounds at the joint. In this research, A7075-T651 and AZ31B alloys were welded using ER5356 filler wire in MIG welding method in butt configuration. 100% argon was used as shielding gas. The results showed that, most of the welding appearances were moderate. The macroscopic investigation at all welding cross section showed that a lot of AlmMgn intermetallic brittle compounds were formed at the interface between weld seam and AZ31B parent metal side which caused macro cracks. A good number of macro pores were also observed at AZ31B parent metal side. These cracks and pores could easily cause the failure of the joint at very low stress.

Ishak, M.; Islam, M. R.

2014-04-01

326

Effect of microalloying on microstructure and hot working behavior for AZ31 based magnesium alloy  

NASA Astrophysics Data System (ADS)

The formability of Mg alloy sheet in the as-hot rolled condition depends on the microstructure developed during hot rolling. In general, the formability of Mg alloys is improved by finer grain sizes. 'Microalloying' levels of calcium (Ca), strontium (Sr), and cerium (Ce) have been found to refine the as-cast structure, but there is no information as to whether this effect will be reflected in the as-hot worked structure and formability. Thus, in this work, the effects of microalloying levels of calcium (Ca), strontium (Sr), and cerium (Ce) on the microstructures (from as-cast to as-hot rolled) and subsequent hot deformation behavior of AZ31, nominally 3% Al, 1% Zn, and 0.3%Mn, were systematically investigated. To include the effect of solidification rate these alloys were cast in different moulds (preheated steel mould, Cu-mould, and water cooled Cu-mould). One-hit compression testing at temperatures between 250°C ˜ 400 °C, strain rates of 0.001, 0.01, 0.1 s-1 and strains from 0.2 up to 1.0, was performed to investigate the basic hot compression behavior, while two-hit compression testing was conducted to determine the static softening behavior. Hot rolling of the microalloyed AZ31 alloys was then carried out to study the effects of microalloying on as-hot rolled structure under two sets of rolling schedules. To investigate the formability of these microalloyed sheets, tensile tests were completed over a temperature range between ambient and 450°C, at strain rates between 0.1 and 0.0003 s-1. Results show that Ca and Sr act to refine the as cast grain size and the second phases, consistently promoting fine and uniform as-hot rolled grain structure. With regard to grain refinement, calcium has the strongest effect, whereas Ce is most effective for second phase refinement. In addition, microalloying retards grain growth during hot tensile testing. Multiple alloying presents a combined and complementary effect. A refined and uniform grain structure combined with well dispersed and thermally stable second phases significantly improves the hot formability of AZ31 sheets by promoting dynamic recrystallization (DRX) in the matrix, resisting grain coarsening, and retarding the development of cavitation and necking. Under the superplastic condition of 450°C and 0.0003 s -1, the elongation was improved by 17% with Ca only, 26% with Ca and Ce, 51% with Ca and Sr, and 59% with Ca, Sr and Ce.

Shang, Lihong

327

AZ-101 Mixer Pump Demonstration and Tests Data Management Analysis Plan  

SciTech Connect

This document provides a plan for the analysis of the data collected during the AZ-101 Mixer Pump Demonstration and Tests. This document was prepared after a review of the AZ-101 Mixer Pump Test Plan (Revision 4) [1] and other materials. The plan emphasizes a structured and well-ordered approach towards handling and examining the data. This plan presumes that the data will be collected and organized into a unified body of data, well annotated and bearing the date and time of each record. The analysis of this data will follow a methodical series of steps that are focused on well-defined objectives. Section 2 of this plan describes how the data analysis will proceed from the real-time monitoring of some of the key sensor data to the final analysis of the three-dimensional distribution of suspended solids. This section also identifies the various sensors or sensor systems and associates them with the various functions they serve during the test program. Section 3 provides an overview of the objectives of the AZ-101 test program and describes the data that will be analyzed to support that test. The objectives are: (1) to demonstrate that the mixer pumps can be operated within the operating requirements; (2) to demonstrate that the mixer pumps can mobilize the sludge in sufficient quantities to provide feed to the private contractor facility, and (3) to determine if the in-tank instrumentation is sufficient to monitor sludge mobilization and mixer pump operation. Section 3 also describes the interim analysis that organizes the data during the test, so the analysis can be more readily accomplished. Section 4 describes the spatial orientation of the various sensors in the tank. This section is useful in visualizing the relationship of the Sensors in terms of their location in the tank and how the data from these sensors may be related to the data from other sensors. Section 5 provides a summary of the various analyses that will be performed on the data during the test program. Finally, an appendix reviews the technical aspects of the key sensor systems that will be used in the program. This review focuses on the performance capabilities and limits of the sensing systems.

DOUGLAS, D.G.

2000-02-22

328

Microstructure, mechanical properties and texture evolution of AZ31 alloy containing trace levels of strontium  

SciTech Connect

The effect of low levels of Sr (0.01, 0.03, 0.05 wt.%) on the microstructure, mechanical properties and texture of AZ31 magnesium alloy has been investigated. Thermodynamic modeling has been used to study the effect of Sr on phase precipitation at different temperatures. Cooling curve analysis reveals a decrease in solidification superheat with the addition of 0.03 wt.% Sr to AZ31. The as-cast microstructures of the alloys have been studied using optical microscopy (OM) and electron probe micro analysis (EPMA). Results show the refining effect of Sr on the grain size and on the {beta}-Mg{sub 17}Al{sub 12} precipitates through growth poisoning and inoculation, respectively. To investigate the mechanical properties of the alloys, as-cast samples were compression tested at elevated temperatures. Hot compression peak stress ({sigma}{sub max}) and critical strain before recrystallization ({epsilon}{sub c}) initially drop but then increase. {sigma}{sub max} first decreases due to the depletion of Al from solid solution and then increases when the amount of the Al-Sr precipitates reach a significant amount. {epsilon}{sub c} drops due to the acceleration of dynamic recrystallization kinetics as a result of grain refinement. It increases with increasing Sr when the concentration Sr in solid solution is increased leading to dislocation pinning and retardation of recrystallization. X-ray texture measurements on the hot compressed and extruded samples show a decrease in maximum intensity of the basal pole figures with increasing Sr as a result of reduced twining and the changes in Al and Sr concentrations in solid solution. - Research Highlights: {yields} Microstructures/precipitates of AZ31+trace levels of Sr were examined by OM and EPMA. {yields} Thermodynamic calculations and cooling curve analysis were used to predict ppt formation. {yields} It has been shown that Sr refines the grains and Mg17Al12 precipitates. {yields} Mechanical properties and texture were studied using hot compression and X-ray diffraction. {yields} Different micro-mechanisms were responsible for mechanical and texture changes.

Sadeghi, Alireza, E-mail: alireza.sadeghi@mail.mcgill.ca; Pekguleryuz, Mihriban

2011-08-15

329

Large cities are less green  

PubMed Central

We study how urban quality evolves as a result of carbon dioxide emissions as urban agglomerations grow. We employ a bottom-up approach combining two unprecedented microscopic data on population and carbon dioxide emissions in the continental US. We first aggregate settlements that are close to each other into cities using the City Clustering Algorithm (CCA) defining cities beyond the administrative boundaries. Then, we use data on CO2 emissions at a fine geographic scale to determine the total emissions of each city. We find a superlinear scaling behavior, expressed by a power-law, between CO2 emissions and city population with average allometric exponent ? = 1.46 across all cities in the US. This result suggests that the high productivity of large cities is done at the expense of a proportionally larger amount of emissions compared to small cities. Furthermore, our results are substantially different from those obtained by the standard administrative definition of cities, i.e. Metropolitan Statistical Area (MSA). Specifically, MSAs display isometric scaling emissions and we argue that this discrepancy is due to the overestimation of MSA areas. The results suggest that allometric studies based on administrative boundaries to define cities may suffer from endogeneity bias. PMID:24577263

Oliveira, Erneson A.; Andrade, José S.; Makse, Hernán A.

2014-01-01

330

CityGML - Interoperable semantic 3D city models  

NASA Astrophysics Data System (ADS)

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 relationship to other standards from the fields of computer graphics and computer-aided architectural design and to the prospective INSPIRE model are discussed, as well as the impact CityGML has and is having on the software industry, on applications of 3D city models, and on science generally.

Gröger, Gerhard; Plümer, Lutz

2012-07-01

331

Fragg Virus - Kinetic City  

NSDL National Science Digital Library

The Fragg Virus is a learning module centered learning the importance of systems; it is a part of the Kinetic City-Mission to Vearth site. In general this module is concerned with how different parts work within a system. The Fragg Virus module is equipped with a computer simulation mind game, creative writing exercises for independent study, and art-centered exercises, as well as lesson plans for hands on games and activities designed for a group. The focus of the activities is evolution and the features of an animal that helps the animal survive in its environment. Certain features explored are the giraffes neck, polar bears fir, and a birds beak.

American Association for the Advancement of Science (;)

2008-04-17

332

USA CityLink  

NSDL National Science Digital Library

When Santa Claus comes to town this year he will be taking an entirely different route. He has decided to harness his reindeer and hop in his sleigh a little earlier than usual to spread his Christmas cheer over the Information Superhighway. Users will be able to access a customizable letter from Santa, the latest Polar weather conditions, some holiday recipes and a special Christmas greeting. They will also be able to preview exciting Christmas gifts and toys which can be ordered from St. Nick's virtual workshop. (USA CityLink).

333

Systematic understanding of corrosion behavior of plasma electrolytic oxidation treated AZ31 magnesium alloy using a mouse model of subcutaneous implant.  

PubMed

This study was conducted to identify the differences between corrosion rates, corrosion types, and corrosion products in different physiological environments for AZ31 magnesium alloy and plasma electrolytic oxidation (PEO) treated AZ31 magnesium alloy. In vitro and in vivo tests were performed in Hank's Balanced Salt Solution (HBSS) and mice for 12 weeks, respectively. The corrosion rates of both AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy were calculated based on DC polarization curves, volume of hydrogen evolution, and the thickness of corrosion products formed on the surface. Micro X-ray computed tomography (Micro-CT), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to analyze morphological and chemical characterizations of corrosion products. The results show that there is more severe localized corrosion after in vitro test in HBSS; however, the thicknesses of corrosion products formed on the surface for AZ31 magnesium alloy and PEO treated AZ31 magnesium alloy in vivo were about 40% thicker than the thickness of corrosion products generated in vitro. The ratio of Ca and P (Ca/P) in the corrosion products also differed. The Ca deficient region and higher content of Al in corrosion product than AZ31 magnesium alloy were identified after in vivo test in contrast with the result of in vitro test. PMID:25491800

Jang, Yongseok; Tan, Zongqing; Jurey, Chris; Collins, Boyce; Badve, Aditya; Dong, Zhongyun; Park, Chanhee; Kim, Cheol Sang; Sankar, Jagannathan; Yun, Yeoheung

2014-12-01

334

Foxa2 and H2A.Z Mediate Nucleosome Depletion during Embryonic Stem Cell Differentiation  

PubMed Central

SUMMARY Nucleosome occupancy is fundamental for establishing chromatin architecture. However, little is known about the relationship between nucleosome dynamics and initial cell lineage specification. Here, we determine the mechanisms that control global nucleosome dynamics during embryonic stem (ES) cell differentiation into endoderm. Both nucleosome depletion and de novo occupation occur during the differentiation process, with higher overall nucleosome density after differentiation. The variant histone H2A.Z and the winged helix transcription factor Foxa2 both act to regulate nucleosome depletion and gene activation, thus promoting ES cell differentiation, while DNA methylation promotes nucleosome occupation and suppresses gene expression. Nucleosome depletion during ES cell differentiation is dependent on Nap1l1-coupled SWI/SNF and INO80 chromatin remodeling complexes. Thus, both epigenetic and genetic regulators cooperate to control nucleosome dynamics during ES cell fate decisions. PMID:23260146

Li, Zhaoyu; Gadue, Paul; Chen, Kaifu; Jiao, Yang; Tuteja, Geetu; Schug, Jonathan; Li, Wei; Kaestner, Klaus H.

2012-01-01

335

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

NASA Astrophysics Data System (ADS)

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.

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

2013-01-01

336

Tank 241-AZ-101 prototype corrosion probe four month status report  

SciTech Connect

High-level nuclear wastes at the Hanford Site are stored underground in carbon steel double-shell and single-shell tanks. The installation of a prototype corrosion monitoring system into double-shell tank 241-AZ-101 was completed in August, 1996. The system monitors fluctuations in corrosion current and potential (electrochemical noise) occurring on three electrode arrays immersed in the waste liquid and in the vapor space above the waste. The system also supports the use of Tafel and linear polarization resistance testing. By monitoring and analyzing the data from these techniques, changes in the corrosive characteristics of the waste have been rapidly detected and correlated with operational changes in the tank.

Edgemon, G.L., Westinghouse Hanford

1996-12-12

337

Simulation of cylindrical cup drawing of AZ31 sheet metal with crystal plasticity finite element method  

NASA Astrophysics Data System (ADS)

As a light-weight structural material, magnesium alloys show good potential in improving the fuel efficiency of vehicles and reducing CO2 emissions. However, it is well known that polycrystalline Mg alloys develop pronounced crystallographic texture and plastic anisotropy during rolling, which leads to earing phenomenon during deep drawing of the rolled sheets. It is vital to predict this phenomenon accurately for application of magnesium sheet metals. In the present study, a crystal plasticity model for AZ31 magnesium alloy that incorporates both slip and twinning is established. Then the crystal plasticity model is implemented in the commercial finite element software ABAQUS/Explicit through secondary development interface (VUMAT). Finally, the stamping process of a cylindrical cup is simulated using the developed crystal plasticity finite element model, and the predicting method is verified by comparing with experimental results from both earing profile and deformation texture.

Tang, Weiqin; Li, Dayong; Zhang, Shaorui; Peng, Yinghong

2013-12-01

338

Evaluation of cracking in the 241-AZ tank farm ventilation line at the Hanford Site  

SciTech Connect

In the period from April to October of 1988, a series of welding operations on the outside of the AZ Tank Farm ventilation line piping at the Hanford Site produced unexpected and repeated cracking of the austenitic stainless steel base metal and of a seam weld in the pipe. The ventilation line is fabricated from type 304L stainless steel pipe of 24 inch diameter and 0.25 inch wall thickness. The pipe was wrapped in polyethylene bubble wrap and buried approximately 12 feet below grade. Except for the time period between 1980 and 1987, impressed current cathodic protection has been applied to the pipe since its installation in 1974. The paper describes the history of the cracking of the pipe, the probable cracking mechanisms, and the recommended future action for repair/replacement of the pipe.

ANANTATMULA, R.P.

1999-10-20

339

Spectral properties of the extreme solar system objects 2012 DR30 and 2013 AZ60  

NASA Astrophysics Data System (ADS)

2012 DR30 and 2013 AZ60 represent two examples of TNOs with very large aphelion distances (2405 and 1951 AU, respectively), thus standing for the currently best candidates of possible scattered-in Oort-cloud objects. Though they possibly shared a similar dynamical scenario, the two bodies exhibit surprisingly diverging prediction for orbital evolution and also quite different surface properties (Kiss et al. 2013, Kiss et al. 2014). Here we compare these optical and infrared photometry and spectra of the two bodies. Both show a generaly flat spectrum, but with significantly differing slope. We find clear signs of water ice on 2013 DR30 particulary, which is an exciting diagnostic of a possible water reservoir at very large perihelion distances, and on the other hand, suggests a close link between the giant cometary nuclei of the Oort Cloud (for that Hale-Bopp is the only known example in our Solar System) and these exotic TNOs.

Szabo, G.; Kiss, Cs.; Duffard, R.; Pinilla-Alonso, N.; Licandro, J.

2014-04-01

340

Femtosecond laser-induced iridescent effect on AZ31B magnesium alloy surface  

NASA Astrophysics Data System (ADS)

Both micro-ripples and nano-ripples were firstly reported at AZ31B magnesium alloy surface irradiated by femtosecond laser in atmospheric environment. Iridescent effect was also demonstrated over a large area of the irradiated surface induced by scanning laser beam. Results revealed that the colour effect was mainly attributed to the nano-ripples with broad distribution of periods acting as diffraction gratings, and intensity of the structural colour was greatly influenced by morphology evolution of the micro-ripples with laser processing. It was suggested that near-field interference between surface plasmons polaritons and incident laser light determined the formation of the nano-ripples, and initial surface roughness combing with such interference lead to the formation of the micro-ripples. Potential applications of such effect on Mg alloys and how to apply the technique to other materials with different properties was further proposed.

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

2013-10-01

341

Effect of equal channel angular pressing on the strength and ductility of an AZ80 alloy  

NASA Astrophysics Data System (ADS)

Equal channel angular pressing (ECAP) was applied to an extruded AZ80 Mg alloy in order to refine microstructure and enhance mechanical properties. The results show that the initial grain size of 20 ?m of the as-extruded samples has been reduced by 75% after the first pass of ECAP, down to about 5 ?m. Also as a result of the severe plastic deformation, the intermetallic compound Mg17Al12, which was distributed along grain boundaries and forms networks before the ECAP, has been re-arranged into a more homogeneous distribution and with a more spherical shape after the ECAP. Although no strengthening effect has been observed, the grain refinement and precipitate fragmentation caused by the ECAP has resulted in a 28% increase in the elongation to failure in tensile tests. Fractography observation and texture measurement have also been carried out.

Pereira, T. S.; Chung, C. W.; Ding, R.; Chiu, Y. L.

2009-08-01

342

Low temperature superplasticity of AZ91 magnesium alloy with non-equilibrium grain boundaries  

SciTech Connect

The superplastic behavior of a fine-grained AZ91 alloy, processed by equal channel angular extrusion, has been investigated in a low temperature range of 423--523 K. The experimental results showed a stress exponent of 2 and the activation energy for superplastic flow was in agreement with that for grain boundary diffusion of magnesium. The alloy with non-equilibrium grain boundary structures exhibited lower superplastic elongation than the alloy with equilibrium grain boundaries. Furthermore, the strain rate for superplastic flow of the former was lower than that of the latter. These differences probably arise because the accommodation process for grain boundary sliding is hampered by the long-range stresses associated with the non-equilibrium grain boundaries.

Mabuchi, M. [National Industrial Research Inst. of Nagoya (Japan)] [National Industrial Research Inst. of Nagoya (Japan); Ameyama, K. [Ritsumeikan Univ., Noji-Higashi, Shiga (Japan). Dept. of Mechanical Engineering] [Ritsumeikan Univ., Noji-Higashi, Shiga (Japan). Dept. of Mechanical Engineering; Iwasaki, H. [Himeji Inst. of Tech., Hyogo (Japan). Dept. of Materials Science and Engineering] [Himeji Inst. of Tech., Hyogo (Japan). Dept. of Materials Science and Engineering; Higashi, K. [Osaka Prefecture Univ., Sakai, Osaka (Japan). Dept. of Metallurgy and Materials Science] [Osaka Prefecture Univ., Sakai, Osaka (Japan). Dept. of Metallurgy and Materials Science

1999-05-28

343

The Influence of Strain Path on Biaxial Compressive Behavior of AZ31 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The strain path dependence of the compressive flow behavior of cast AZ31 magnesium alloy was investigated. Biaxial compression tests with linear strain paths were conducted using a unique biaxial compression device. It was found that the equivalent stress-strain relations varied according to the strain paths. The work contour for linear strain paths was well described by the Logan-Hosford yield criterion. Biaxial compressions with abrupt strain path change were also carried out to investigate the influences of the prestrain amplitude and angular relation of the sequential strain paths on the flow behavior. Rapid increase in the equivalent stress was observed just after the abrupt strain path change. These specific flow behaviors were discussed with regard to the plastic anisotropy, which showed rapid evolution in the early stage of the biaxial compressions.

Shimizu, Ichiro; Tada, Naoya; Nakayama, Kosuke

344

Numerical analysis of self-pierce riveting of AZ31 magnesium alloy sheets  

NASA Astrophysics Data System (ADS)

Magnesium alloy sheet has a broad development prospect for lightweight metal in automotive industry. Selfpierce Riveting (SPR) process is a suitable joining technology to fasten materials of different nature. This paper is concerned with the development of numerical models of the SPR process of AZ31 magnesium alloy sheet. Based on DEFORM-2D finite element software, a two-dimensional axisymmetric model has been built for the SPR process. Then the distribution of stress and strain, and the stroke-load curve are analyzed in the forming process of the riveting. After a 2D simulation of SPR process, the quality of riveted joint is evaluated in terms of joint cross-sectional shape. The results show a better understanding of mechanical properties of SPR joints of magnesium alloy sheets. As a sufficient interlock and bottom thickness leading to a reasonably good joint, the numerical simulation method plays a significant role to predict the final strength of the joint.

Han, S. L.; Wu, Y. W.; Zeng, Q. L.; Gao, Y.

2013-05-01

345

Initiation of fatigue cracks in AZ91 Mg alloy processed by ECAP  

NASA Astrophysics Data System (ADS)

Mechanism of fatigue crack initiation was investigated in ultrafine-grained (UFG) magnesium alloy AZ91 processed by equal channel angular pressing (ECAP). Fatigue behaviour of UFG material was compared to the behaviour of material in an initial as-cast state. Focused ion beam technique (FIB) was applied to reveal the surface relief and early fatigue cracks. Two substantially different mechanisms of crack initiation were observed in UFG structure, which can be characterized as bimodal even after 6 ECAP passes by route Bc. The bimodality consists in a coexistence of very fine grained areas with higher content of Mg17Al12 particles and areas exhibiting somewhat larger grains and lower density of particles. The fatigue cracks which initiate in areas of larger grains are related to the cyclic slip bands; this initiation mechanism is similar to that observed in cast alloy. The second initiation mechanism is related to the grain boundary cracking which takes place predominantly in the fine grained areas.

Fintová, S.; Kunz, L.

2014-08-01

346

Fatigue behaviour of friction stir processed AZ91 magnesium alloy produced by high pressure die casting  

SciTech Connect

The room temperature fatigue properties of AZ91 magnesium alloy produced by high pressure die casting (HPDC) as cast, heat treated, friction stir processed (FSP) and FSP and heat treated were studied. The fatigue properties of the material were evaluated for the HPDC magnesium alloy in the as-received state and after a solution treatment at 415 deg. C for 2 h and an ageing treatment at 220 deg. C for 4 h. The heat treatment resulted in a significant increase in the fatigue properties of the HPDC material, while no significance influence of heat treatment was recorded in the FSP condition. The morphology of fracture surfaces was examined by employing a field emission gun scanning electron microscope (FEGSEM)

Cavaliere, P. [INFM-Dept. of 'Ingegneria dell'Innovazione', Engineering Faculty, University of Lecce, Via per Arnesano, 73100, Lecce (Italy)]. E-mail: pasquale.cavaliere@unile.it; De Marco, P.P. [INFM-Dept. of 'Ingegneria dell'Innovazione', Engineering Faculty, University of Lecce, Via per Arnesano, 73100, Lecce (Italy)

2007-03-15

347

Constructing cities, deconstructing scaling laws  

PubMed Central

Cities can be characterized and modelled through different urban measures. Consistency within these observables is crucial in order to advance towards a science of cities. Bettencourt et al. have proposed that many of these urban measures can be predicted through universal scaling laws. We develop a framework to consistently define cities, using commuting to work and population density thresholds, and construct thousands of realizations of systems of cities with different boundaries for England and Wales. These serve as a laboratory for the scaling analysis of a large set of urban indicators. The analysis shows that population size alone does not provide us enough information to describe or predict the state of a city as previously proposed, indicating that the expected scaling laws are not corroborated. We found that most urban indicators scale linearly with city size, regardless of the definition of the urban boundaries. However, when nonlinear correlations are present, the exponent fluctuates considerably. PMID:25411405

Arcaute, Elsa; Hatna, Erez; Ferguson, Peter; Youn, Hyejin; Johansson, Anders; Batty, Michael

2015-01-01

348

Constructing cities, deconstructing scaling laws.  

PubMed

Cities can be characterized and modelled through different urban measures. Consistency within these observables is crucial in order to advance towards a science of cities. Bettencourt et al. have proposed that many of these urban measures can be predicted through universal scaling laws. We develop a framework to consistently define cities, using commuting to work and population density thresholds, and construct thousands of realizations of systems of cities with different boundaries for England and Wales. These serve as a laboratory for the scaling analysis of a large set of urban indicators. The analysis shows that population size alone does not provide us enough information to describe or predict the state of a city as previously proposed, indicating that the expected scaling laws are not corroborated. We found that most urban indicators scale linearly with city size, regardless of the definition of the urban boundaries. However, when nonlinear correlations are present, the exponent fluctuates considerably. PMID:25411405

Arcaute, Elsa; Hatna, Erez; Ferguson, Peter; Youn, Hyejin; Johansson, Anders; Batty, Michael

2015-01-01

349

Software configuration management plan, 241-AY and 241-AZ tank farm MICON automation system  

SciTech Connect

This document establishes a Computer Software Configuration Management Plan (CSCM) for controlling software for the MICON Distributed Control System (DCS) located at the 241-AY and 241-AZ Aging Waste Tank Farm facilities in the 200 East Area. The MICON DCS software controls and monitors the instrumentation and equipment associated with plant systems and processes. A CSCM identifies and defines the configuration items in a system (section 3.1), controls the release and change of these items throughout the system life cycle (section 3.2), records and reports the status of configuration items and change requests (section 3.3), and verifies the completeness and correctness of the items (section 3.4). All software development before initial release, or before software is baselined, is considered developmental. This plan does not apply to developmental software. This plan applies to software that has been baselined and released. The MICON software will monitor and control the related instrumentation and equipment of the 241-AY and 241-AZ Tank Farm ventilation systems. Eventually, this software may also assume the monitoring and control of the tank sludge washing equipment and other systems as they are brought on line. This plan applies to the System Cognizant Manager and MICON Cognizant Engineer (who is also referred to herein as the system administrator) responsible for the software/hardware and administration of the MICON system. This document also applies to any other organizations within Tank Farms which are currently active on the system including system cognizant engineers, nuclear operators, technicians, and control room supervisors.

Hill, L.F.

1997-10-30

350

Development of Magnesium Powder Metallurgy AZ31 Alloy Using Commercially Available Powders  

NASA Astrophysics Data System (ADS)

Magnesium and its alloys are attractive materials for use in automotive and aerospace applications because of their low density and good mechanical properties. However, difficulty in forming magnesium and the limited number of available commercial alloys limit their use. The present work reviews the efforts to improve the attractiveness of magnesium through non-traditional processing, and presents the results of producing AZ31 magnesium alloy via powder metallurgy P/M. P/M can be used to alleviate the formability problem through near-net-shape processing, and also allows unique chemical compositions that can lead to the development of new alloys with novel properties. The feasibility of producing magnesium powder metallurgy products utilizing the industrially dominant process of mixed powder blending, uni-axial die compaction and controlled atmosphere sintering was investigated. An alloy composition based on the commercial Mg alloy AZ31 (3 mass % Al, 1 mass % Zn) was used to facilitate the comparison to similar wrought product. The optimal processing conditions (compaction pressure, sintering time and temperature) were found to maximize sintered density and mechanical properties. Results show that sintering temperature is one of the major variables that has an appreciable effect on the final properties of the samples, and that the effects of compaction pressure and sintering time were insignificant. The material showed poor tensile properties, with a maximum tensile strength of 32 MPa due to lack of sufficient densification. The latter was related to the lack of liquid phase formed during sintering of Al/Zn magnesium alloys and the barrier to diffusion due to the presence of the stable magnesium surface layer.

Burke, Paul; Kipouros, Georges J.

2011-04-01

351

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

NASA Astrophysics Data System (ADS)

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.

Kondori, Babak; Benzerga, A. Amine

2014-07-01

352

AGU Press Briefing May 29th: Urban Ecology of Phoenix, AZ.  

NSDL National Science Digital Library

Ecologists now accept human beings and our activities as a significant influence on the Earths ecology. ASTER data is being used to better understand urban ecology, in particular how humans build their cities and affect the surrounding environment. Will Stefanov of Arizona State University will present the first set of ASTER images of the urban skeleton of the amount of built structures in 12 cities around the world and discuss the Urban Environmental Monitoring project which will examine 100 urban centers to look for common features (or lack of them) in global city structure and monitor change over time.

Snodgrass, Stuart; Stefanov, Will

2001-05-22

353

A new definition of cities.  

PubMed

The authors introduce a new map of Britain, which is based on the city region concept and designed specifically to present data from the 1981 census. The primary purposes of this article are "to describe the main problems and distortions which result from using current administrative areas, outline the key features of the new way of defining British cities, and demonstrate the value of the new geographical framework with some basic statistics on city size and population trends." PMID:12314601

Champion, T; Coombes, M; Openshaw, S

1983-11-01

354

[Migration to metropolitan Mexico City].  

PubMed

Accelerated urbanization, especially after 1940, has been among the great transformations in Mexico associated with rapid and sustained economic growth during 1950-80. The urbanization process was highly selective, favoring in particular Mexico City, Guadalajara, and Monterey, which together contain about 25% of Mexicożs total population. Metropolitan Mexico City alone contained around 18.2% of the total 1990 population on 0.2% of Mexicożs land area. Mexico Cityżs population grew at an average annual rate of 4.2%, from 1.6 million in 1940 to 14.8 million in 1990, largely due to in-migration. Migrants and their reproduction are estimated to have accounted for 51.2% of Mexico Cityżs growth since 1940, and physical expansion of the metropolitan zone for another 5.7%. Slightly over 80% of migrants come from 10 states that are mostly rural, relatively densely populated, not distant, and below average in living levels. Women predominate slightly. Nearly half of migrants are aged 15-29 years on arrival. The proportion with no more than primary education is higher than that of Mexico City natives, but the proportion with post-secondary education is similar. Pollution, lack of public safety, and other urban problems will probably combine to discourage migration to Mexico City in the future and encourage departures to less difficult cities. PMID:12158091

Cantu Gutierrez, J J; Luque Gonzalez, R

1990-01-01

355

Smart cities of the future  

NASA Astrophysics Data System (ADS)

Here we sketch the rudiments of what constitutes a smart city which we define as a city in which ICT is merged with traditional infrastructures, coordinated and integrated using new digital technologies. We first sketch our vision defining seven goals which concern: developing a new understanding of urban problems; effective and feasible ways to coordinate urban technologies; models and methods for using urban data across spatial and temporal scales; developing new technologies for communication and dissemination; developing new forms of urban governance and organisation; defining critical problems relating to cities, transport, and energy; and identifying risk, uncertainty, and hazards in the smart city. To this, we add six research challenges: to relate the infrastructure of smart cities to their operational functioning and planning through management, control and optimisation; to explore the notion of the city as a laboratory for innovation; to provide portfolios of urban simulation which inform future designs; to develop technologies that ensure equity, fairness and realise a better quality of city life; to develop technologies that ensure informed participation and create shared knowledge for democratic city governance; and to ensure greater and more effective mobility and access to opportunities for urban populations. We begin by defining the state of the art, explaining the science of smart cities. We define six scenarios based on new cities badging themselves as smart, older cities regenerating themselves as smart, the development of science parks, tech cities, and technopoles focused on high technologies, the development of urban services using contemporary ICT, the use of ICT to develop new urban intelligence functions, and the development of online and mobile forms of participation. Seven project areas are then proposed: Integrated Databases for the Smart City, Sensing, Networking and the Impact of New Social Media, Modelling Network Performance, Mobility and Travel Behaviour, Modelling Urban Land Use, Transport and Economic Interactions, Modelling Urban Transactional Activities in Labour and Housing Markets, Decision Support as Urban Intelligence, Participatory Governance and Planning Structures for the Smart City. Finally we anticipate the paradigm shifts that will occur in this research and define a series of key demonstrators which we believe are important to progressing a science of smart cities.

Batty, M.; Axhausen, K. W.; Giannotti, F.; Pozdnoukhov, A.; Bazzani, A.; Wachowicz, M.; Ouzounis, G.; Portugali, Y.

2012-11-01

356

Salt Lake City, Utah  

NASA Technical Reports Server (NTRS)

The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This simulated natural color image presents a late spring view of north central Utah that includes all of the Olympic sites. The image extends from Ogden in the north, to Provo in the south; and includes the snow-capped Wasatch Mountains and the eastern part of the Great Salt Lake.

This image was acquired on May 28, 2000 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, a long-term research and technology program designed to examine Earth's land, oceans, atmosphere, ice and life as a total integrated system.

The broad spectral coverage and high spectral resolution of ASTER will provide scientists in numerous disciplines with critical information for surface mapping, and monitoring dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

Size: 63.5 x 123.3 km (38.1 x 74 miles) Location: 40.7 deg. North lat., 111.9 deg. West long. Orientation: North at top Image Data: ASTER bands 1,2, and 3. Original Data Resolution: 15 m Date Acquired: May 28, 2000

2001-01-01

357

Kansas City Hopewell  

NSDL National Science Digital Library

In 2003, the University of Kansas Museum of Anthropology was awarded a Digital Library Initiatives grant for a project that would result in this rather useful and interesting digitization project. The hope was that the museum would be able to digitize some of the excellent collection of material recovered from the 30 Kansas City Hopewell archaeological sites that are located around the junction of the Kansas and Missouri Rivers. Most of the sites date to the Middle Woodland or Early Ceramic period, which ranges from 100 B.C. to 700 A.D. One of the fine features of this site is the 3D images area, which includes 32 excavated items that visitors may view in their entirety. The site is rounded out by a selection of helpful suggested readings and a collection of external links to sites such as those of the Society for American Archaeology and ArchNet.

358

Shaping Livable Cities  

NSDL National Science Digital Library

Thinking about policy solutions for urban regions is a great deal easier than actually putting them into action, and that is why this latest report from The International Development Research Centre in Canada is most welcome. This recently released 36-page report starts off with this important sentence: "They [cities] are engines of economic growth and cultural prosperity, but they are also centres of pollution and poverty." Divided into three substantive chapters, the report provides specific case studies of various urban innovations, such as Beijing's urban agriculture initiatives and a program designed to integrate agriculture into municipal planning in Kampala, Uganda. Other studies draw on experiences in Vancouver, Hyderabad, and Managua. Overall, the report is well written and may be of great interest to persons in the fields of international development as well as scholars interested in evaluating such programs.

Taboulchanas, Kristina

2006-01-01

359

CurioCity: Articles  

NSDL National Science Digital Library

The CurioCity E-Zine from LetâÂÂs Talk Science is geared toward precocious teens, but there is plenty for adults to enjoy as well. Readers can browse articles in a variety of subjects, including Consumer Science, Entertainment, Environment, Health, In the News, Sports, and Tech Buzz. Typical offerings include gems like âÂÂThrowaway Sex Organsâ (re: sea slugs) and âÂÂCan Eating Peanuts Cure Peanut Allergies?â The site also offers dozens of short videos on topics as diverse as Neil Armstrong on Being an Engineer, and The Math and Mystery of Murmurations. Also, dig into the Themes section, where topics are divided by Biotechnology, Sky Science, and Spotlight on Energy. Teachers will especially want to explore the Educators link, where they can register for free curriculum-based, classroom-ready resources on STEM subjects.

360

76 FR 18753 - City of Springfield, Illinois, City Water, Light and Power; Notice of Filing  

Federal Register 2010, 2011, 2012, 2013, 2014

...City of Springfield, Illinois, City Water, Light and Power; Notice of Filing Take...City of Springfield, Illinois, City Water, Light and Power (CWLP), filed its...cost-based revenue requirements for Reactive Supply and Voltage Control from...

2011-04-05

361

Educating Cities in Latin America  

ERIC Educational Resources Information Center

This article considers the development of educating cities from a political perspective, illustrating in detail the diversity of organisations and individuals involved and the challenges they are facing. Bearing in mind that educating cities were established from the 1990s onwards in Europe and spread to other continents from there, the purpose of…

Messina, Graciela; Valdés-Cotera, Raúl

2013-01-01

362

Dropouts in Great City Schools.  

ERIC Educational Resources Information Center

The dropout problem in the nation, in the Council of the Great City Schools (GCS) school districts, and in the central cities is reviewed. Annual, single-year, four-year, and status dropout rates are examined. During the decade from 1982 to 1992, the gap in dropout rate between Whites and other ethnic groups has narrowed. The majority of the GCS…

Urban Indicator, 1994

1994-01-01

363

Fabled Lost Cities The Mediterranean  

E-print Network

Fabled Lost Cities of The Mediterranean Italy, Croatia, Albania, Sicily, Turkey & Greece ( Aboard led to a new course on The Mediterranean City in the 2nd -6th Centuries. Dr. James Wiseman, lecturer for the Archaeological Institute of America, is an expert on Mediterranean archaeology, history, and art from prehistoric

Rowley, Clarence W.

364

Planning for a City's Future  

NSDL National Science Digital Library

This lesson plan asks students to consider how knowledge of geography and history can help prepare for the future. Students will research the geography and history of a city and write reports explaining how city leaders can use this information to plan for the future.

365

City Planning Unit: Grade 6.  

ERIC Educational Resources Information Center

Described is a project designed to make government lessons and economics more appealing to sixth-grade students by having them set up and run a model city. General preparation procedures and set-up of the project, specific lesson plans, additional activities, and project evaluation are examined. An actual 3-dimensional model city was set up on…

Dalton, William Edward

366

Great Cities Institute Faculty Scholar  

E-print Network

Domestic Violence Court and community- based agencies focusing on substance abuse treatment and domesticGreat Cities Institute Faculty Scholar Lecture Cook County Domestic Violence Court: Policies and Procedures When Substance Abuse and Intimate Partner Violence Co-Occur Great Cities Institute College

Illinois at Chicago, University of

367

NEW YORK CITY NONPROFIT EXECUTIVE  

E-print Network

NEW YORK CITY NONPROFIT EXECUTIVE OUTLOOK SURVEY CO-SPONSORED: BARUCH COLLEGE, SCHOOL OF PUBLIC BLUM, AND NANCY WIEFEK HUMAN SERVICES COUNCIL OF NEW YORK CITY FEDERATION OF PROTESTANT WELFARE AGENCIES UJA­FEDERATION OF NEW YORK UNITED NEIGHBORHOOD HOUSES OF NEW YORK IN COOPERATION: ASIAN AMERICAN

Rosen, Jay

368

Sinking cities. [Rising sea level  

Microsoft Academic Search

Although the rapid subsidence of the last 50 years now appears slowed or even arrested in many cities, there has been almost no recovery in ground elevation, and many of the world's great cities remain vulnerable to flooding from the sea. The continuing rise in sea level challenges the engineering efforts designed to keep out the sea. Over the past

R. Dolan; H. G. Goodell

2009-01-01

369

Human diffusion and city influence  

E-print Network

Cities are characterized by concentrating population, economic activity and services. However, not all cities are equal and hierarchy in terms of influence at local, regional or global scales naturally emerges. Traditionally, there have been important efforts to describe this hierarchy by indirect measures such the sharing of company headquarters, traffic by air, train or boats or economical exchanges. In this work, we take a different approach and introduce a method that uses geolocated Twitter information to quantify the impact of cities on rural or other urban areas. Since geolocated tweets are becoming a global phenomenon, the method can be applied at a world-wide scale. We focus on $58$ cities and analyze the mobility patterns of people after visiting them for the first time. Cities such as Rome and Paris appear consistently as those with largest area covered by Twitter users after their visit and as those attracting visitors most diverse in origin. The study is also performed discerning users mobility b...

Lenormand, Maxime; Tugores, Antňnia; Ramasco, José J

2015-01-01

370

Garden City Schools' Media Centers  

NSDL National Science Digital Library

Welcome to Garden City Public Schools Media Centers Web Pages. The Goal of the Garden City Public Schools' Media Centers is to provide access to information to students, staff, and community in both print and electronic formats. Our goal is to instill the importance of not only reading but also of information and technology literacy skills. High School Media Resource Center Media Specialist: Ms. Nancy Schultz-Speck; Librarian Paraprofessional: Mrs. Carol Garrett; 6500 Middlebelt Road, Garden City, MI 48135 (734) 762-8350 ext. 221 Email: schultn@gardencityschools.com MRC HOURS: 7am until 2:20pm - MRC Schedule Garden City Middle School Media Center Media Specialist:; 1851 Radcliff, Garden City, MI 48135 (734) 762-8400 District s Online Catalog - Destiny - Access the OPAC to ...

Ms. Schultz

2007-03-26

371

A framework for integrating scenario studies across applications Holly C. Hartmann, Arid Lands Information Center, University of Arizona, Tucson, AZ 85721  

E-print Network

Information Center, University of Arizona, Tucson, AZ 85721 The use of climate change scenarios to support of these approaches in a complementary, rather than competitive, fashion that also connects scenario activities from

Miami, University of

372

In vitro and in vivo metabolism of (14)C-AZ11, a novel inhibitor of bacterial DNA gyrase/type II topoisomerase.  

PubMed

Abstract 1.?(2R,4S,4aS)-11-Fluoro-2,4-dimethyl-8-((S)-4-methyl-2-oxooxazolidin-3-yl)-2,4,4a,6-tetrahydro-1H,1'H-spiro [isoxazolo[4,5-g][1,4]oxazino[4,3-a]quinoline-5,5'-pyrimidine]-2',4',6'(3'H)-trione (AZ11) is a novel mode-of-inhibition bacterial topoisomerase inhibitor that entered preclinical development for the treatment of Gram-positive bacteria infection. 2.?The in vitro biotransformation studies of AZ11 using mouse, rat, dog and human hepatocytes showed low-intrinsic clearance in all species attributed to microsomal metabolism. 3.?After a single intravenous administration of [(14)C]AZ11 in bile duct cannulated rats, the mean percentage of dose recovered in rat urine, bile and feces was approximately 18, 36 and 42%, respectively. Unchanged AZ11 recovered in rat urine and bile was less than 9% of the dose, indicating that AZ11 underwent extensive metabolism in rats. 4.?The most abundant in vivo metabolite detected in urine and bile was M1 formed via ring opening on the piperidine and morpholine rings accounting for 20% of the administered dose. The major fecal metabolite was M5, which accounted for approximately 32% of administered dose. M5 was not formed when AZ11 incubated with rat intestinal microsomes and cytosol but was formed when incubated with fresh rat feces, suggesting that unchanged AZ11 was directly excreted into gut lumen where M5 formed as an intestinal microflora-mediated product. This process could have significant impact on bioavailability or exposure of AZ11 in rat. PMID:25142218

Guo, Jian; Joubran, Camil; Luzietti, Ricardo A; Zhou, Fei; Basarab, Gregory S; Vishwanathan, Karthick

2015-02-01

373

Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80  

Microsoft Academic Search

Stress corrosion cracking (SCC) of the high-performance rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) was studied using slow strain rate test (SSRT) method in air, distilled water and 0.5wt.% NaCl solution. For comparison, the well-known AZ80 alloy was also studied. All alloys were susceptible to SCC in 0.5wt.% NaCl solution and distilled water to some extent. AZ80

M. Bobby Kannan; W. Dietzel; C. Blawert; A. Atrens; P. Lyon

2008-01-01

374

An electron back-scattered diffraction study on the microstructure evolution of AZ31 Mg alloy during equal channel angular extrusion  

Microsoft Academic Search

Microstructure evolution of AZ31 Mg alloy during equal channel angular extrusion (ECAE) was investigated by electron back-scattered diffraction (EBSD). The grains of AZ31 Mg alloy were refined significantly after ECAE 1–8 passes at 498K and the distributions of grain size tended to be more uniform with pass number increasing. Frequency of sub-boundaries and low angle grain boundaries (LAGBs) increased at

Li Jin; Dongliang Lin; Dali Mao; Xiaoqin Zeng; Wenjiang Ding

2006-01-01

375

Twin Cities Metro Advanced Practice Center  

E-print Network

Twin Cities Metro Advanced Practice Center In An Emergency: Equipment & Supplies List for Food Vietnamese.................................12 #12;Twin Cities Metro Advanced Practice Center Funded Offsite cold storage options (contact info for truck, warehouse) #12;Twin Cities Metro Advanced Practice

376

A Crystalline Plasticity Finite Element Method for Simulation of the Plastic Deformation of AZ31 Magnesium Alloys  

NASA Astrophysics Data System (ADS)

In this paper, a constitutive framework based on a crystalline plasticity model is employed to simulate the plastic deformation of AZ31 magnesium alloy, which posses the hexagonal close packed (HCP) crystal structure. Dislocation slip and mechanical twinning are taken into account in the model. The successive integration method is used to determine the active slip systems, and the contribution of twinning to the grain reorientation is treated by the PTR method. The FE model is introduced into ABAQUS/Explicit through a user material subroutine (VUMAT). Three deformation processes of AZ31 magnesium alloy, including tension, compression and a stamping process, are simulated with the present method. The simulation results are compared with experiment and those presented in the literature.

Li, Dayong; Zhang, Shaorui; Tang, Weiqin; Huang, Shiyao; Peng, Yinghong

2010-06-01

377

Application of YAG Laser TIG Arc Hybrid Welding to Thin AZ31B Magnesium Alloy Sheet  

NASA Astrophysics Data System (ADS)

A magnesium alloy is said to be an ecological material with high ability of recycling and lightweight property. Especially, magnesium alloys are in great demand on account of outstanding material property as a structural material. Under these circumstances, research and development of welding process to join magnesium alloy plates are of great significance for wide industrial application of magnesium. In order to use it as a structure material, the welding technology is very important. TIG arc welding process is the most ordinary process to weld magnesium alloy plates. However, since the heat source by the arc welding process affects the magnesium alloy plates, HAZ of welded joint becomes wide and large distortion often occurs. On the other hand, a laser welding process that has small diameter of heat source seems to be one of the possible means to weld magnesium alloy in view of the qualitative improvement. However, the low boiling point of magnesium generates some weld defects, including porosity and solidification cracking. Furthermore, precise edge preparation is very important in butt-welding by the laser welding process, due to the small laser beam diameter. Laser/arc hybrid welding process that combines the laser beam and the arc is an effective welding process in which these two heat sources influence and assist each other. Using the hybrid welding, a synegistic effect is achievable and the disadvantages of the respective processes can be compensated. In this study, YAG laser/TIG arc hybrid welding of thin magnesium alloy (AZ31B) sheets was investigated. First of all, the effect of the irradiation point and the focal position of laser beam on the quality of a weld were discussed in hybrid welding. Then, it was confirmed that a sound weld bead with sufficient penetration is obtained using appropriate welding conditions. Furthermore, it was made clear that the heat absorption efficiency is improved with the hybrid welding process. Finally, the tensile tests of welded joints were performed, and it was confirmed that they have sufficient mechanical properties. As a result of this study, it is confirmed that, if the appropriate welding conditions are selected, sound welded joints of AZ31B magnesium alloy are obtainable by the YAG laser/TIG arc hybrid welding process.

Kim, Taewon; Kim, Jongcheol; Hasegawa, Yu; Suga, Yasuo

378

Effect of high-intensity ultrasonic field on process of semi-continuous casting for AZ80 magnesium alloy billets  

Microsoft Academic Search

Under the high-intensity ultrasonic field, AZ80 magnesium alloy was semi-continuously cast. The effects of ultrasonic intensity on the as-cast microstructures and mechanical properties were investigated. The results show that the microstructures of the alloy cast under high-intensity ultrasonic field are fine and uniform, and the grains are equiaxed, rose-shaped or globular with an average size of 257 ?m. High-intensity field

Zhi-qiang ZHANG; Qi-chi LE; Jian-zhong CUI

2010-01-01

379

Observation of Micro-scale Surface Morphology with Microtexture Development During Plane Strain Tensile Deformation in AZ31 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The change of microstructure including microtexture and surface morphology in AZ31 magnesium alloy under plane strain tension was investigated by 3D observation combined confocal microscope and high-resolution electron backscattered diffraction. Micro-scale changes in the surface morphology were observed on the area including tensile twin bands. The mechanism for surface morphology variation was discussed with the nucleation of tensile twinning and the strain partitioning caused by continuing deformation after the nucleation of the twins.

Lee, Keunho; Kim, Kyung Il; Kim, Se-Jong; Suh, Dong-Woo; Oh, Kyu Hwan; Han, Heung Nam

2015-01-01

380

Mechanical properties and microstructure of AZ31 Mg alloy processed by two-step equal channel angular extrusion  

Microsoft Academic Search

A new equal channel angular extrusion (ECAE) processing, two-step ECAE, was applied to control the microstructure and mechanical properties of AZ31 Mg alloy. The ultra-fine grain size of 0.5 ?m has been produced, and both the ductility and yield stress of the alloy were significantly increased after the processing, which is ascribed to grain refinement as well as incomplete dynamic

Li Jin; Dongliang Lin; Dali Mao; Xiaoqing Zeng; Wenjiang Ding

2005-01-01

381

Uniformity and continuity of effective strain in AZ91D processed by multi-pass equal channel angular extrusion  

Microsoft Academic Search

AZ91D magnesium alloy was processed by equal channel angular extrusion(ECAE). The influence of extrusion temperature, extrusion pass and extrusion route on the ultimate strength of the extruded billet was analyzed. The process of multi-pass extrusion was simulated with the method of finite element analysis, and the continuity and uniformity of effective strain in multi-pass extrusion were investigated. The results show

Xiao-hua ZHANG; Shou-jing LUO; Zhi-ming DU

2008-01-01

382

Formation of an aluminum-alloyed coating on AZ91D magnesium alloy in molten salts at lower temperature  

Microsoft Academic Search

An aluminum-alloyed coating was formed on an AZ91D magnesium alloy in molten salts containing AlCl3 at a lower temperature of 380°C. The microstructure and phase constitution of the alloyed layer were investigated by optical microscopy, scanning electron microscopy, energy dispersive spectrum and X-ray diffraction. The nano-hardness of the coating was studied by nanoindentation associated with scanning probe microscopy. The corrosion

C. Zhong; M. F. He; L. Liu; Y. J. Chen; B. Shen; Y. T. Wu; Y. D. Deng; W. B. Hu

2010-01-01

383

Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters  

SciTech Connect

An iron phosphate composition for vitrifying a high sulfate (~17 wt%) and high alkali (~80 wt%) low activity Hanford waste, known as AZ102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ102 which corresponded to a total alkali and sulfate (SO3) content of 21 and 4.2 wt%, respectively. A slurry (7M Na) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090°C for 10 days in a small JHM at PNNL and for 7 days in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their CCC-treated counterparts met the DOE LAW requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT). These glass waste forms retained up to 77 % of the SO3 (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium, surrogate for Tc-99, all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition (slurry feed) was melted continuously in the JHM and CCIM, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste.

Day, Delbert E.; Brow, R. K.; Ray, C. S.; Kim, Cheol-Woon; Reis, Signo T.; Vienna, John D.; Peeler, David K.; Johnson, Fabienne; Hansen, E. K.; Sevigny, Gary J.; Soelberg, Nicolas R.; Pegg, Ian L.; Gan, Hao

2012-01-05

384

9.28 Bedrock Rivers KX Whipple and RA DiBiase, Arizona State University, Tempe, AZ, USA  

E-print Network

9.28 Bedrock Rivers KX Whipple and RA DiBiase, Arizona State University, Tempe, AZ, USA BT Crosby 550 9.28.1.1 Definition and Occurrence 551 9.28.1.2 Importance of Bedrock Rivers 551 9.28.1.3 Relation of Flow Hydraulics 552 9.28.2.2 Controls on the Width of Bedrock Rivers 553 9.28.3 Erosion Processes

Crosby, Benjamin T.

385

Deposition of histone H2A.Z by the SWR-C remodeling enzyme prevents genome instability.  

PubMed

The yeast SWR-C chromatin remodeling enzyme catalyzes chromatin incorporation of the histone variant H2A.Z which plays roles in transcription, DNA repair, and chromosome segregation. Dynamic incorporation of H2A.Z by SWR-C also enhances the ability of exonuclease I (Exo1) to process DNA ends during repair of double strand breaks. Given that Exo1 also participates in DNA replication and mismatch repair, here we test whether SWR-C influences DNA replication fidelity. We find that inactivation of SWR-C elevates the spontaneous mutation rate of a strain encoding a L612M variant of DNA polymerase (Pol) ?, with a single base mutation signature characteristic of lagging strand replication errors. However, this genomic instability does not solely result from reduced Exo1 function, because single base mutator effects are seen in both Exo1-proficient and Exo1-deficient pol3-L612M swr1? strains. The data are consistent with the possibility that incorporation of the H2A.Z variant by SWR-C may stimulate Exo1 activity, as well as enhance the fidelity of replication by Pol ?, the repair of mismatches generated by Pol ?, or both. PMID:25463393

Van, Christopher; Williams, Jessica S; Kunkel, Thomas A; Peterson, Craig L

2015-01-01

386

Development of a Binary Zn-Based Solder Alloy for Joining Wrought Magnesium Alloy AZ31B  

NASA Astrophysics Data System (ADS)

In the present article, the wrought magnesium alloy AZ31B sheets were soldered by means of high-frequency induction heating device using a novel binary Zn-based solder alloy in argon gas shield condition. The interfacial microstructure, phase constitution, and fracture morphology of the soldered joint were studied. The microhardness and shear strength of the soldered joint were tested. The experimental results exhibit that ?-Mg solid solution and ?-MgZn phase were formed in soldering region. Moreover, the ?-Mg7Zn3 phase in the original Zn-based solder alloy disappeared completely after the soldering process due to the fierce alloying between the molten binary Zn-based solder alloy and the base metal AZ31B during soldering. Test results show that the shear strength of the soldered joint is 28 MPa. The fracture morphology of the soldered joint displays an intergranular fracture mode, and the crack originates from ?-Mg + ?-MgZn eutectoid structure. The interaction between the molten Zn-based solder alloy and the base metal AZ31B leads the Zn-based solder alloy to be transformed into Mg-based soldering metal during soldering.

Ma, Li; Long, Weimin; Qiao, Peixin; He, Dingyong; Li, Xiaoyan

2013-01-01

387

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

PubMed

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 10? cycles in air compared to 20MPa at 10? cycles tested in SBF at 37°C. A fatigue limit of 110MPa at 10? cycles in air was observed for extruded WE43 alloy compared to 40MPa at 10? 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. PMID:20656074

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

388

Producing Nanocomposite Layer on the Surface of As-Cast AZ91 Magnesium Alloy by Friction Stir Processing  

NASA Astrophysics Data System (ADS)

Friction stir processing (FSP) is an effective tool to produce a surface composite layer with enhanced mechanical properties and modified microstructure of as-cast and sheet metals. In the present work, the mechanical and microstructural properties of as-cast AZ91 magnesium alloy were enhanced by FSP and an AZ91/SiC surface nanocomposite layer has been produced using 30 nm SiC particles. Effect of the FSP pass number on the microstructure, grain size, microhardness, and powder distributing pattern of the surface developed has been investigated. The developed surface nanocomposite layer presents a higher hardness, an ultra fine grain size and a better homogeneity. Results show that, increasing the number of FSP passes enhances distribution of nano-sized SiC particles in the AZ91 matrix, decreases the grain size, and increases the hardness significantly. Also, changing of the tool rotating direction results much uniform distribution of the SiC particles, finer grains, and a little higher hardness.

Asadi, P.; Besharati Givi, M. K.; Faraji, G.

389

Nature in the City  

NSDL National Science Digital Library

Nature in the City is a project of the Earth Island Institute, and is "wholly dedicated to ecological conservation, restoration and stewardship of the [San] Franciscan bioregion." Their website's "About" section gives a thorough explanation of not only their goals, as well as a definition of nature. Furthermore, this section provides some philosophical insight into what exactly "urban nature" happens to be. Those visitors interested in a more visceral tour of San Francisco should check out the "Photo Gallery" link, and they should be sure to check out the "Natural Areas" album to view some eerie-looking oak woodlands in Golden Gate Park. Additionally, visitors to the site who are interested in the life that teems on Alcatraz Island will enjoy file number fourteen which includes an image of roosting double-crested cormorants on a dramatic hillside. Finally the "Local Ecology" link has an explanation of the "Biodiversity Crisis" in San Francisco, which can be attributed to ecological, political, institutional, social and cultural factors.

390

The Ancient City of Petra  

NSDL National Science Digital Library

This fun Web article is part of OLogy, where kids can collect virtual trading cards and create projects with them. Here, they learn about the ancient city of Petra. The article begins with an overview of this city, which was located along the ancient trade routes between Arabia, Egypt, and the Mediterranean Sea. Kids then have the chance to take a walk through Petra's ruins. This clickable illustration has 11 places for them to explore. The article concludes with an extensive information section on the history of the city.

391

Deformation Behavior of AZ80 Wrought Magnesium Alloy at Cryogenic Temperatures  

SciTech Connect

The influence of temperature on the deformation and failure behavior of AZ80 wrought Mg alloy has been examined from 77K to 298K. It is found that the yield strength (YS) and ultimate strength (UTS) are increasing with the temperature decreasing, while the elongation is decreasing especial between 213K and 143K. Based on the mechanical tests, observation of environmental scanning electron microscope (ESEM) and transmission electron microscope (TEM), it is proposed that the alloy deforms mainly by slips and twins, but undergoes different mechanism of cleavage in the range of testing temperature. At T>213K, the alloy ductility is higher because the dislocations could pass through twins but pile up at precipitate phase: Mg17Al12, which causes the crack nucleate. At T<143K, the alloy ductility is lower because the dislocation slip are suppressed greatly and dislocations pile up at twins, and cause crack nucleate and expand along twins quickly. At 143K

Tang Wei; Li Xiuyan; Han Enhou; Xu Yongbo; Li Yiyi [Institute of Metal Research, Chinese Academy of Science, Shenyang, Liaoning, 110016 (China)

2006-03-31

392

The Effect of Mn-rich Precipitates on the Strength of AZ31 Extrudates  

NASA Astrophysics Data System (ADS)

The commercial magnesium alloy AZ31 has been subjected to a range of solution treatment regimes. These have then been extruded and their microstructure, texture, and precipitate populations characterized along with their mechanical properties. During the solution treatment, Mn-enriched particles develop and these remain largely unchanged throughout subsequent processing steps. A direct link between grain size and texture has been found, with coarser-grained specimens showing sharper textures. VPSC modeling has been used to quantify the effect of texture on the tensile yield strength, and it has been found that sharper textures have larger tensile yield strengths. Since coarser grain sizes have reduced Hall-Petch hardening, but have an additional texture-strengthening component, a region on the Hall-Petch plot for tension has been identified in which there is an insensitivity of strength to grain size. This has been quantitatively modeled and a texture-modified Hall-Petch plot for tension has been developed. The Mn-rich particles have also been shown to provide precipitate strengthening to the alloy of up to 40 MPa. The compressive behavior was clearer, with the compressive yield strength being directly correlated to grain size and unaffected by texture or precipitation hardening.

Stanford, Nicole; Atwell, Dale

2013-10-01

393

Microstructure and mechanical properties of AZ91 magnesium alloy subject to deep cryogenic treatments  

NASA Astrophysics Data System (ADS)

AZ91 magnesium alloy was subjected to a deep cryogenic treatment. X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electronic microscopy (TEM) methods were utilized to characterize the composition and microstructure of the treated samples. The results show that after two cryogenic treatments, the quantity of the precipitate hardening ? phase increases, and the sizes of the precipitates are refined from 8-10 ?m to 2-4 ?m. This is expected to be due to the decreased solubility of aluminum in the matrix at low temperature and the significant plastic deformation owing to internal differences in thermal contraction between phases and grains. The polycrystalline matrix is also noticeably refined, with the sizes of the subsequent nanocrystalline grains in the range of 50-100 nm. High density dislocations are observed to pile up at the grain boundaries, inducing the dynamic recrystallization of the microstructure, leading to the generation of a nanocrystalline grain structure. After two deep cryogenic treatments, the tensile strength and elongation are found to be substantially increased, rising from 243 MPa and 4.4% of as-cast state to 299 MPa and 5.1%.

Li, Gui-rong; Wang, Hong-ming; Cai, Yun; Zhao, Yu-tao; Wang, Jun-jie; Gill, Simon P. A.

2013-09-01

394

Study on Pressurized Solidification Behavior and Microstructure Characteristics of Squeeze Casting Magnesium Alloy AZ91D  

NASA Astrophysics Data System (ADS)

Squeeze casting technology for magnesium alloys has a great application potential in automobile manufacturing and has received increasing attention from both academic and industrial communities. In this study, the pressurized solidification behavior of magnesium alloy AZ91D in squeeze casting process was investigated using computer-aided cooling curve analysis (CA-CCA). It was found that the applied pressure increased both the start and end temperatures of primary ?-Mg formation but had little effect on the sizes of temperature ranges. Moreover, the applied pressure increased the start temperature and decreased the end temperature of eutectic reaction during the solidification, resulting in a larger temperature range of eutectic reaction compared with solidification under atmospheric pressure. The grains were remarkably refined, and the eutectic fraction increased with increasing applied pressure. The dendritic microstructure with a larger secondary dendrite arm spacing (SDAS) was observed under a higher applied pressure at the central part of the experimental casting. By correlating the CA-CCA and SDAS data, it was found that SDAS and the cooling rate at the maximum ?-Mg growth could be fit into the power law equation in classic solidification theories.

Han, Zhiqiang; Pan, Haowei; Li, Yanda; Luo, Alan A.; Sachdev, Anil K.

2015-02-01

395

Effects of Zr Additions on the Microstructure and Impression Creep Behavior of AZ91 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The effects of 0.2, 0.6, and 1.0 wt pct Zr additions on the microstructure and creep behavior of AZ91 Mg alloy were investigated by impression tests carried out under constant punching stress ( ? imp) in the range 100 to 650 MPa, corresponding to the modulus-compensated stress levels of {{0.007 le ?_{{imp}} } {G le 0.044}} , at temperatures in the range 425 K to 570 K (152 °C to 297 °C). The alloy containing 0.6 wt pct Zr showed the best creep resistance mainly due to the favorable formation of Al3Zr2 and Al2Zr intermetallic compounds, reduction in the volume fraction of the eutectic ?-Mg17Al12 phase, and solid solution hardening effects of Al in the Mg matrix. Based on the obtained stress exponents of 4.2 to 6.5 and activation energies of 90.7 to 127.1 kJ/mol, it is proposed that two parallel mechanisms of lattice and pipe-diffusion-controlled dislocation climb compete. Dislocation climb controlled by dislocation pipe diffusion prevails at high stresses, whereas climb of edge dislocations is the controlling mechanism at low stresses.

Kabirian, F.; Mahmudi, R.

2010-12-01

396

Low-temperature plastic deformation of AZ31 magnesium alloy with different microstructures  

NASA Astrophysics Data System (ADS)

The plastic deformation of AZ31 magnesium alloy under tension at temperatures of 4.2-295K is studied as a function of its microstructure following squeeze casting (SC) and after severe plastic deformation (SPD) by hot rolling and equal-channel angular pressing. SPD reduces the average grain size and creates a texture that favors basal-plane dislocation glide. It is found that plastic deformation becomes unstable (serrated) at temperatures of 4.2-25K and more stress jerks occur in the SPD polycrystal than in the SC alloy. The temperature dependence of the yield stress of the alloy is typical of thermally activated unpinning of dislocations from short-range barriers. The ratio of the yield stresses for the SPD and SC alloys at a given temperature is explained by hardening owing to a reduction in grain size and softening owing to a favorable texture. As the grain size is reduced, the rate of strain hardening of the alloy falls off, but its ductility (strain to fracture) increases because of the texture. The strain rate sensitivity of the alloy for T ?100K is independent of microstructure and is determined by intersections with forest dislocations. As the temperature is raised over 150-295K the strain rate sensitivity becomes greater owing to activation of dynamic recovery and an enhanced contribution from diffusion processes during plastic deformation of micrograined materials.

Estrin, Yu. Z.; Zabrodin, P. A.; Braude, I. S.; Grigorova, T. V.; Isaev, N. V.; Pustovalov, V. V.; Fomenko, V. S.; Shumilin, S. E.

2010-12-01

397

Rate sensitivity and tension-compression asymmetry in AZ31B magnesium alloy sheet.  

PubMed

The constitutive response of a commercial magnesium alloy rolled sheet (AZ31B-O) is studied based on room temperature tensile and compressive tests at strain rates ranging from 10(-3) to 10(3)?s(-1). Because of its strong basal texture, this alloy exhibits a significant tension-compression asymmetry (strength differential) that is manifest further in terms of rather different strain rate sensitivity under tensile versus compressive loading. Under tensile loading, this alloy exhibits conventional positive strain rate sensitivity. Under compressive loading, the flow stress is initially rate insensitive until twinning is exhausted after which slip processes are activated, and conventional rate sensitivity is recovered. The material exhibits rather mild in-plane anisotropy in terms of strength, but strong transverse anisotropy (r-value), and a high degree of variation in the measured r-values along the different sheet orientations which is indicative of a higher degree of anisotropy than that observed based solely upon the variation in stresses. This rather complex behaviour is attributed to the strong basal texture, and the different deformation mechanisms being activated as the orientation and sign of applied loading are varied. A new constitutive equation is proposed to model the measured compressive behaviour that captures the rate sensitivity of the sigmoidal stress-strain response. The measured tensile stress-strain response is fit to the Zerilli-Armstrong hcp material model. PMID:24711496

Kurukuri, Srihari; Worswick, Michael J; Ghaffari Tari, Dariush; Mishra, Raja K; Carter, Jon T

2014-05-13

398

Constitutive model of AZ31B sheet at various pre-strains and temperatures  

NASA Astrophysics Data System (ADS)

Due to their high specific strength, vibration absorption capability, and excellent corrosion resistance, Mg alloys have been potential alternative to other lightweight materials in the automotive industry. Mg alloys are known to have unique mechanical properties; i.e., yielding asymmetry, anisotropy, unusual hardening behavior at room temperature. Usually, Mg alloy sheets have inferior formability at room temperature, but the formability increases when the temperature increases. Moreover, the asymmetry and anisotropy become less significant due to the activation of non-basal slip systems at higher temperature. Utilizing this unique properties, the forming of Mg alloy sheets has been frequently conducted at the temperature of 200 °C or higher, at which twinning effect is less dominant. However, the forming process at elevated temperature lowers production speed due to the additional heating and cooling stages. To resolve this problem, studies on technology that maximizes the formability of Mg alloy sheets at lower temperature have been widely conducted. In this paper, the response of AZ31B Mg alloy sheets under tension-compression cyclic loading at different pre-strains and temperatures was measured experimentally. Then a practical hardening model was developed to reproduce the measured stress-strain responses, which can be applied to the simulation of sheet metal forming of Mg alloy sheets.

Kim, Heon Young; Seo, Oh Suk; Lee, Chung An; Kim, Ji Hoon; Nguyen, Ngoc-Trung; Lee, Myoung-Gyu

2013-12-01

399

Failure analysis of AZ31 magnesium alloy sheets based on the extended GTN damage model  

NASA Astrophysics Data System (ADS)

Based on the Gurson-Tvergaard-Needleman (GTN) model and Hill's quadratic anisotropic yield criterion, a combined experimental-numerical study on fracture initiation in the process of thermal stamping of Mg alloy AZ31 sheets was carried out. The aim is to predict the formability of thermal stamping of the Mg alloy sheets at different temperatures. The presented theoretical framework was implemented into a VUMAT subroutine for ABAQUS/EXPLICIT. Internal damage evolution due to void growth and coalescence developed at different temperatures in the Mg alloy sheets was observed by scanning electron microscopy (SEM). Moreover, the thermal effects on the void growth, coalescence, and fracture behavior of the Mg alloy sheets were analyzed by the extended GTN model and forming limit diagrams (FLD). Parameters employed in the GTN model were determined from tensile tests and numerical iterative computation. The distribution of major and minor principal strains in the specimens was determined from the numerical results. Therefore, the corresponding forming limit diagrams at different stress levels and temperatures were drawn. The comparison between the predicted forming limits and the experimental data shows a good agreement.

Wang, Rui-ze; Chen, Zhang-hua; Li, Yu-jie; Dong, Chao-fang

2013-12-01

400

Histone Variant H2A.Z and RNA Polymerase II Transcription Elongation ?  

PubMed Central

Nucleosomes containing histone variant H2A.Z (Htz1) serve to poise quiescent genes for activation and transcriptional initiation. However, little is known about their role in transcription elongation. Here we show that dominant mutations in the elongation genes SPT5 and SPT16 suppress the hypersensitivity of htz1? strains to drugs that inhibit elongation, indicating that Htz1 functions at the level of transcription elongation. Direct kinetic measurements of RNA polymerase II (Pol II) movement across the 9.5-kb GAL10p-VPS13 gene revealed that the elongation rate of polymerase is 24% slower in the absence of Htz1. We provide evidence for two nonexclusive mechanisms. First, we observed that both the phospho-Ser2 levels in the elongating isoform of Pol II and the loading of Spt5 and Elongator over the GAL1 open reading frame (ORF) depend on Htz1. Second, in the absence of Htz1, the density of nucleosome occupancy is increased over the GAL10p-VPS13 ORF and the chromatin is refractory to remodeling during active transcription. These results establish a mechanistic role for Htz1 in transcription elongation and suggest that Htz1-containing nucleosomes facilitate Pol II passage by affecting the correct assembly and modification status of Pol II elongation complexes and by favoring efficient nucleosome remodeling over the gene. PMID:21357739

Santisteban, Maria Soledad; Hang, Mingda; Smith, M. Mitchell

2011-01-01

401

Creep behavior of an AZ91 magnesium alloy reinforced with alumina fibers  

SciTech Connect

Creep tests were conducted at elevated temperatures on an AZ91 alloy reinforced with 20 vol pct Al{sub 2}O{sub 3} fibers. When the creep data are interpreted by incorporating a threshold stress into the analysis, it is shown that the true stress exponent, n, is {approximately}3 at the lower stress levels and increases to >3 at the higher stresses. The true activation energy for creep is close to the value anticipated for interdiffusion of aluminum in magnesium. This behavior is interpreted in terms of a viscous glide process with n = 3 and a breakaway of the dislocations from their solute atom atmospheres at the higher stress levels. The threshold stresses in this composite appear to arise from an attractive interaction between mobile dislocations in the matrix alloy and Mg{sub 17}Al{sub 12} precipitates. The experimental results reveal several important similarities between the creep behavior of this magnesium-based composite and the well-documented creep properties of aluminum-based composites.

Li, Y.; Langdon, T.G. [Univ. of Southern California, Los Angeles, CA (United States)

1999-08-01

402

Assessment of in vitro temporal corrosion and cytotoxicity of AZ91D alloy.  

PubMed

Magnesium alloys represent a valuable option for the production of bioresorbable implantable medical devices aimed to improve the therapeutic approach and minimize the potential risks related to biostable materials. In this regard, the degradation process needs to be carefully evaluated in order to assess the effectiveness of the regenerative support and the eventual toxic effects induced by the released corrosion products. Aluminium is one of the most common alloying element that raised several safety concerns, contributing to shift the investigation toward Al-free alloys. To delve into this issue, a long-term investigation (up to 28 days) was performed using AZ91D alloy, due to its relevant Al content. Immersion tests in phosphate buffered saline (PBS) solution was performed following the ASTM standards and the corrosion behaviour was evaluated at fixed time points by means of electrochemical techniques. Cytotoxic effects were assessed by culturing human neuroblastoma cells with conditioned medium derived from immersion tests at different dilution degree. An increase in the resistance corrosion with the time was observed. In all the investigated cases the presence of Al in the conditioned media did not induce significant toxic effects directly correlated to its content. A decrease of cell viability was only observed in the case of 50 % dilution of PBS conditioned for the longest immersion period (i.e., 28 days). PMID:22802105

Del Gaudio, Costantino; Bagalŕ, Paolo; Venturini, Marco; Grandi, Claudio; Parnigotto, Pier Paolo; Bianco, Alessandra; Montesperelli, Giampiero

2012-10-01

403

Growth and characterization of Mg(OH) 2 film on magnesium alloy AZ31  

NASA Astrophysics Data System (ADS)

Magnesium-based biomaterials have been proposed as potential candidates for biodegradable implant materials, such as bone screws, bone plates, intraluminal stents and so on. However, the poor corrosion resistance inhibits their applications in surgery. They collapse before the injured tissues are healed. In this paper, Mg(OH) 2 nonstructural film was synthesized on the substrate of AZ31 magnesium alloy by hydrothermal method with NaOH solution as mineralizer to reduce the corrosion rate of magnesium-based materials. The obtained films were characterized by XRD, SEM, and XPS. The results showed that a Mg(OH) 2 film with nanostructure surface can be synthesized by hydrothermal method. It was observed that the thickness of film increased with the holding time. Corrosion rates of the films were studied by immersing the samples in Hank's solution (37 °C). Surface deposits of samples with films soaked in Hank's solution for 31 days were investigated by XRD, SEM, EDS, XPS, and FTIR. It verified that the corrosion rate of the magnesium alloy with grown film was slowed down in the Hank's solution and the behavior of corrosion was inhibited effectively. Amorphous calcium apatite precursor was observed to deposit on the surface of the film during corrosion experiments in Hank's solution. And the tape test revealed a strong adhesion between the film and the substrate.

Zhu, Yanying; Wu, Guangming; Zhang, Yun-Hong; Zhao, Qing

2011-05-01

404

Transient Liquid Phase Diffusion Bonding of Magnesium Alloy (Mg-AZ31) to Titanium Alloy (Ti-6Al-4V)  

NASA Astrophysics Data System (ADS)

The magnesium alloy Mg-AZ31 and titanium alloy Ti-6Al-4V have physical characteristics and mechanical properties that makes it attractive for a wide range of engineering applications in the aerospace and automotive industries. However, the differences in melting temperature and coefficient of thermal expansion hinder the use of traditional fusion welding techniques. Transient liquid phase (TLP) bonding of magnesium alloy Mg-AZ31 and titanium alloy Ti-6Al- 4V was performed and different interlayer types and configurations were used to facilitate joint formation. The joining of these alloys using Ni foils was successful at a bonding temperature of 515°C, bonding pressure 0.2 MPa, for bonding time of 5 minutes. At the Ni/Mg-AZ31 bond interface, the formation of a eutectic liquid between Mg and Ni was observed. The formation of Mg2Ni and Mg3AlNi2 were identified along the bond interface resulting in an isothermally solidified joint. At the Ni/Ti-6Al-4V interface, the solid-state diffusion process results in joint formation. The use of double Ni-Cu sandwich joint resulted in further enhancement in joint formation and this produced joints with greater shear strength values. The configuration of Mg-AZ31/Cu- Ni/Ti-6Al-4V or Mg-AZ31/Ni-Cu/Ti-6Al-4V influence the mechanism of bonding and the type of intermetallics formed within the joint. The application of thin Ni electrodeposited coatings resulted in further enhancements of joint quality due to better surface-to-surface contact and a reduction in the formation of intermetallics at the joint. The effect of Cu nano-particles in the coatings was found to decrease the eutectic zone width and this resulted in an increase the shear strength of the joints. The highest shear strength of 69 MPa was possible with bonds made using coatings containing Cu nano-particle dispersion.

Atieh, Anas Mahmoud

405

Layout of Ancient Maya Cities  

NASA Astrophysics Data System (ADS)

Although there is little doubt that the ancient Maya of Mesoamerica laid their cities out based, in part, on astronomical considerations, the proliferation of "cosmograms" in contemporary scholarly discourse has complicated matters for the acceptance of rigorous archaeoastronomical research.

Aylesworth, Grant R.

406

[The monster and the city].  

PubMed

"Negative aesthetic categories" and, specifically, the idea of monsters and monstrosity, are used in this discussion of urban phenomena and their relation to modern art. The reflection on monstrosity as a metaphor for the city draws upon such disparate sources as Greek philosophers, Freudian theory, and recent art criticism. It compares dictionary definitions of monster to a general concept of cities, judging the modern metropolis to be "excessively large or extraordinary," "disfigured and ugly," and even "cruel" and "perverse" as demonstrated in social pathologies such as terrorism that breed in cities. The relationship between monstrosity and the city is evident in a variety of artistic manifestations and can be seen in the work of planners, architects, and artists. The examination opens up promising areas for future research in greater depth. PMID:12349000

Calvo Albizu, A

1996-01-01

407

Florida Cities and Metro Areas  

NSDL National Science Digital Library

This exercise for an Urban Sociology course provides a look at demographics in Florida Metropolitan Area. This activity uses The Statistical Abstract of the United States, The County and City Data Book and The State and Metropolitan Area Data Book.

Jim Wright

408

The self-aware city  

E-print Network

This thesis explores the idea of real-time urban space management. While increasing amounts of real-time information about the city, specifically the location of people and resources, appear, it becomes necessary to explore ...

Sevtsuk, Andres

2006-01-01

409

A tale of four cities.  

PubMed

Some of you may not know it, but you live in ManSheffLeedsPool. This label was invented to describe a composite of four cities in the north of England: Manchester, Sheffield, Leeds and Liverpool. PMID:25563112

Buchan, James

2015-01-01

410

Metroscope - Web sites by city  

NSDL National Science Digital Library

Metroscope is a directory of resources arranged by metropolitan area. It contains over four thousand sites. Subject category breakdown under each site includes arts and entertainment, business, media, sports, and professional services. The directory is searchable by subject and across cities. A fast and powerful way to access the Internet resources of over 40 U.S. and five international cities, with new sites being added weekly. The site is provided by the Isotropic Media Group.

411

Automobile emissions in Mexico City  

SciTech Connect

In order to determine the exhaust characteristics of the Mexico City vehicle fleet, a Fuel Efficiency Automotive Test (FEAT) unit was placed at 5 different sites over a 10 day period from 11 February 1991 through 21 February 1991. Valid data for the percent of carbon Monoxide (CO), hydrocarbons (HC), and carbon dioxide (CO{sub 2}) were obtained on 31 838 vehicles. This represents approximately 1 % of the entire Mexico City fleet.

Beaton, S.; Bishop, G.; Stedman, D.

1996-09-01

412

Network Structure and City Size  

PubMed Central

Network structure varies across cities. This variation may yield important knowledge about how the internal structure of the city affects its performance. This paper systematically compares a set of surface transportation network structure variables (connectivity, hierarchy, circuity, treeness, entropy, accessibility) across the 50 largest metropolitan areas in the United States. A set of scaling parameters are discovered to show how network size and structure vary with city size. These results suggest that larger cities are physically more inter-connected. Hypotheses are presented as to why this might obtain. This paper then consistently measures and ranks access to jobs across 50 US metropolitan areas. It uses that accessibility measure, along with network structure variables and city size to help explain journey-to-work time and auto mode share in those cities. A 1 percent increase in accessibility reduces average metropolitan commute times by about 90 seconds each way. A 1 percent increase in network connectivity reduces commute time by 0.1 percent. A 1 percent increase in accessibility results in a 0.0575 percent drop in auto mode share, while a 1 percent increase in treeness reduces auto mode share by 0.061 percent. Use of accessibility and network structure measures is important for planning and evaluating the performance of network investments and land use changes. PMID:22253764

Levinson, David

2012-01-01

413

Sustainable Development of the Learning City  

ERIC Educational Resources Information Center

Kaunas is the second largest city in Lithuania and has strong links with its large rural hinterland. Working from the ideas and examples in "Learning Cities for a Learning Century," (Longworth, 1999) and through contact with other cities that have already implemented lifelong learning concepts, the city has, since 2001, started out on the journey…

Juceviciene, Palmira

2010-01-01

414

A Method of City Informatization Level Evaluation  

Microsoft Academic Search

According to the characteristics and trends of city informatization this paper established a set of evaluation index system of city informatization based on the essence of city informatization. Furthermore, the evaluation model, which is to provide feasible method for the appraisal of city informatization level, is brought out with the application of entropy-weight coefficient method.

Li Xiaoqing; Liu Binghui

2010-01-01

415

World cities or great cities? A comparative study of five Asian metropolises  

Microsoft Academic Search

Few researchers have studied world cities from the perspective of sustainable development. This paper argues that in this era of globalization cities should aspire to be great cities, rather than just world cities. Great cities are places with an enlightened mode of governance; where technological and economic advancement sustain global and local development, thereby enriching socio-economic, human, cultural and environmental

Mee Kam Ng; Peter Hills

2003-01-01

416

Press Release from Dublin City University Dublin City University Licenses CAD Technology to UK Medical Imaging  

E-print Network

Press Release from Dublin City University 12th March 2010 Dublin City University Licenses CAD Technology to UK Medical Imaging Company Biotronics3D Ltd. Dublin City University (DCU) has agreed to license Foundation Ireland (SFI Principal Investigator). #12;About Dublin City University Dublin City University (www

Whelan, Paul F.

417

Source apportionment of fine particulate matter in Phoenix, AZ, using positive matrix factorization  

SciTech Connect

Speciated particulate matter PM2.5 data collected as Part. of the Interagency Monitoring of Protected Visual Environments (IMPROVE) program in Phoenix, AZ, from April 2001 through October 2003 were analyzed using the multivariate receptor model, positive matrix factorization (PMF). Over 250 samples and 24 species were used, including the organic carbon and elemental carbon analytical temperature fractions from the thermal optical reflectance method. A two-step approach was used. First, the species excluding the carbon fractions were used, and initially eight factors were identified; non-soil potassium was calculated and included to better refine the burning factor. Next, the mass associated with the burning factor was removed, and the data set rerun with the carbon fractions. Results were very similar (i.e., within a few percent), but this step enabled a separation of the mobile factor into gasoline and diesel vehicle emissions. The identified factors were burning (on average 2% of the mass), secondary transport (7%), regional power generation (13%), dust (25%), nitrate (9%), industrial As/Pb/Se (2%), Cu/Ni/V (7%), diesel (9%), and general mobile (26%). Most of the long-range transport of emissions emanates from south of Phoenix in Southeastern Arizona, West Texas, and Mexico, which are significant source regions of SO{sub 2} emissions from coal- and oil-fired power plants. The overall contribution from mobile sources also increased, as some mass (OC and nitrate) from the nitrate and regional power generation factors were apportioned with the mobile factors. This approach allowed better apportionment of carbon as well as total mass. Additionally, the use of multiple supporting analyses, including air mass trajectories, activity trends, and emission inventory information, helped increase confidence in factor identification. 86 refs., 10 figs., 2 tabs.

Steven G. Brown; Anna Frankel; Sean M. Raffuse; Paul T. Roberts; Hilary R. Hafner; Darcy J. Anderson [Sonoma Technology, Inc., Petaluma, CA (United States)

2007-06-15

418

Hot Tensile Deformation Characteristics and Processing Map of Extruded AZ80 Mg Alloys  

NASA Astrophysics Data System (ADS)

The hot deformation behaviors of extruded AZ80 Mg alloys were investigated using tension tests. True stress-true strain curves were obtained for deformation at temperatures from 250 to 450 °C with the strain rate range from 0.001 to 0.08 s-1. Optical microscopy analysis was performed to correlate microstructural changes to the flow behaviors. Based on the flow stress, the processing map at a strain of 0.18 was developed using the dynamic materials model theory and can be divided into three zones, including stability zones, change-over region, and instability zones. In stability zones, there are two dynamic recrystallization regions: one region with a peak efficiency of 58% at 350 °C and a strain rate of 0.001 s-1 called domain I; another region with a peak efficiency of 58% at 400 °C and a strain rate of 0.01 s-1 taken as domain II. The apparent activation energy for domain I was estimated to be 100.71 kJ/mol, indicating that short-circuit diffusion process is along the grain boundaries and falls at lower temperatures and lower strain rates. A lattice self-diffusion is considered to be rate controlling mechanism with the apparent activation energy estimated as 140.32 kJ/mol at higher temperatures and higher strain rates in domain II. The change-over region is the zone from domain I to domain II, in which the grains abnormally grow. In instability zones, twins, local deformation band, wedge cracking, and matrix cracking were observed, suggesting that these processing parameters for hot tension in this zone are inapplicable.

Lou, Yan; Chen, Heng; Ke, Changxing; Long, Min

2014-05-01

419

Plastic Deformation Characteristics Of AZ31 Magnesium Alloy Sheets At Elevated Temperature  

SciTech Connect

Using lightweight materials is the emerging need in order to reduce the vehicle's energy consumption and pollutant emissions. Being a lightweight material, magnesium alloys are increasingly employed in the fabrication of automotive and electronic parts. Presently, magnesium alloys used in automotive and electronic parts are mainly processed by die casting. The die casting technology allows the manufacturing of parts with complex geometry. However, the mechanical properties of these parts often do not meet the requirements concerning the mechanical properties (e.g. endurance strength and ductility). A promising alternative can be forming process. The parts manufactured by forming could have fine-grained structure without porosity and improved mechanical properties such as endurance strength and ductility. Because magnesium alloy has low formability resulted form its small slip system at room temperature it is usually formed at elevated temperature. Due to a rapid increase of usage of magnesium sheets in automotive and electronic industry it is necessary to assure database for sheet metal formability and plastic yielding properties in order to optimize its usage. Especially, plastic yielding criterion is a critical property to predict plastic deformation of sheet metal parts in optimizing process using CAE simulation. Von-Mises yield criterion generally well predicts plastic deformation of steel sheets and Hill'1979 yield criterion predicts plastic deformation of aluminum sheets. In this study, using biaxial tensile test machine yield loci of AZ31 magnesium alloy sheet were obtained at elevated temperature. The yield loci ensured experimentally were compared with the theoretical predictions based on the Von-Mises, Hill, Logan-Hosford, and Barlat model.

Park, Jingee; Lee, Jongshin [Graduate School, Kyungpook National University, Deagu 702-701 (Korea, Republic of); You, Bongsun [Department of Materials Technology, Korea Institute of Machinery and Materials, Changwon 641-831 (Korea, Republic of); Choi, Seogou [Digital Production Processing and Forming Team, Korea Institute of Industrial Technology, Incheon 406-800 (Korea, Republic of); Kim, Youngsuk [Department of Mechanical Engineering, Kyoungpook National University, Deagu 702-701 (Korea, Republic of)

2007-05-17

420

Kinetic City - Mission to Vearth  

NSDL National Science Digital Library

"Kinetic City" is a fun, Web-based after-school science club for kids, ages 8 through 11. It combines exciting online animations and activities with boxes of hands-on science experiments. Children earn "Kinetic City" power points and collect stickers as they complete missions and learn standards-based science content. Here's how it works: The "Kinetic City" super crew (Keisha, Curtis, Megan and Max) needs the help of Earth kids to save their planet Vearth, from the science-distorting computer virus Deep Delete. Each of Deep Delete's 60 hideous strains attacks a different area of science with disastrous consequences. After each attack, teams of Earth kids fight back by viewing a short online animation describing the situation on Vearth; performing a series of activities to re-learn the lost science and going on a mission to Vearth during which they answer science questions and gobble up Deep Delete viruses. Their scores appear on their own Kinetic City Club Web page. "Kinetic City" is produced by the American Association for the Advancement of Science (AAAS), with a grant from the National Science Foundation. AAAS writes the "Project 2061 Benchmarks for Science Literacy," which forms the basis of most state science standards.

American Association for the Advancement of Science (AAAS;)

2005-01-01

421

Organization of World Heritage Cities  

NSDL National Science Digital Library

Created in 1993, the Organization of World Heritage Cities (OWHC) has been given a mandate by the United Nations to protect the cultural, historical, and social heritage of the world's great cities. For a number of years, the organization has worked towards this goal by publishing helpful "how to" materials for any number of interested parties, including city officials, heritage groups, and concerned citizens. Recently, this site was created in an attempt to bring these materials together at one online destination. On this site, visitors can learn about case studies (such as those designed to rehabilitate the urban core of Havana), read publications on how to preserve the built environment, and peruse a list of related links. The publications area is quite strong, as it contains a number of introductory works such as "A History of Architectural Conservation" by Jukka Joklehto and "Standards in Preventive Conservation" by Rebeca Alcantra.

2005-01-01

422

Diffusion Bonding Behavior and Characterization of Joints Made Between 316L Stainless Steel Alloy and AZ31 Magnesium Alloy  

NASA Astrophysics Data System (ADS)

The 316L austenitic stainless steel and AZ31 magnesium alloy have physical and mechanical properties which makes these alloys suitable in a number of high technology based industries such as the aerospace and automotive sectors. However, for these alloys to be used in engineering applications, components must be fabricated and joined successfully. The differences in the physical and metallurgical properties between these two alloys prevents the use of conventional fusion welding processes commonly employed in aerospace and transport industry. Therefore, alternative techniques need to be developed and diffusion bonding technology is a process that has considerable potential to join these two dissimilar alloys. In this research work both solid-state and transient liquid phase (TLP) bonding processes were applied. The solid-state bonding of 316L steel to AZ31 magnesium alloy was possible at a bonding temperature of 550°C for 120 minutes using a pressure of 1.3 MPa. The interface characterization of the joint showed a thin intermetallic zone rich in Fe-Al was responsible for providing a metallurgical bond. However, low joint shear strengths were recorded and this was attributed to the poor surface to surface contact. The macro-deformation of the AZ31 alloy prevented the use of higher bonding pressures and longer bonding times. In order to overcome these problems, the TLP bonding process was implemented using pure Cu and Ni foils as interlayers which produced a eutectic phase at the bonding temperature. This research identified the bonding mechanism through microstructural and differential scanning calorimetry investigations. The microstructural characterization of the TLP joints identified intermetallics which became concentrated along the 316L steel/AZ31 bond interface due to the "pushing effect" of the solid/liquid interface during isothermal solidification stage of bonding. The size and concentration of the intermetallics had a noticeable effect on the final joint strength properties. TLP bonding using electrodeposited coatings of Cu and Ni were used as a way of controlling the volume of eutectic liquid formed at the joint. Theoretical and experimental work showed that the use of thin coatings was successful in reducing the size and amount of intermetallics formed at the joint and this had the effect on increasing joint shear strength values.

Elthalabawy, Waled Mohamed

423

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

PubMed

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. PMID:24125587

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

2014-01-01

424

A Tale of Two Machines: A review of the BLAST meeting, Tucson, AZ, January 20–24, 2013  

PubMed Central

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. PMID:24125587

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

2013-01-01

425

Estimate of the Distribution of Solids Within Mixed Hanford Double-Shell Tank AZ-101: Implications for AY-102  

SciTech Connect

This paper describes the current level of understanding of the suspension of solids in Hanford double-shell waste tanks while being mixed with the baseline configuration of two 300-horsepower mixer pumps. A mixer pump test conducted in Tank AZ-101 during fiscal year 2000 provided the basis for this understanding. Information gaps must be filled to demonstrate the capability of the baseline feed delivery system to effectively mix, sample, and deliver double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) for vitrification.

Wells, Beric E.; Ressler, Jennifer J.

2009-04-29

426

The mechanical properties and microstructures of AZ91D magnesium alloy processed by selective laser cladding with Al powder  

NASA Astrophysics Data System (ADS)

This work focuses on the effects of selective laser cladding using Al powder on the properties and microstructure of Mg alloy AZ91D, with different experimental parameters. The scanning strategy was inspired by the alternately hard-soft shell surface structures. The microstructure was greatly refined. Furthermore, the growth of the ?-Mg17Al12 dendrite was curbed. The treatment depth is ~900 ?m. The UTS, YS and microhardness were notably increased. However, the ductility was decreased by a part. The output power of 2200 W and the scanning speed of 180 mm/min are the optimum combination. The resulting wear resistance was thus the highest of all.

Lin, Pengyu; Zhang, Zhihui; Ren, Luquan

2014-08-01

427

Smart Financing for Smart Cities  

E-print Network

with no sign of slowing down 2Confidential Property of Schneider Electric ESL-KT-14-11-29 CATEE 2014: Clean Air Through Efficiency Conference, Dallas, Texas Nov. 18-20 This dilemma is impacted further by l l b l t dsevera g o a mega- ren s Urbanization... Digitization Economic Industrialization 3Confidential Property of Schneider Electric Rebalancing ESL-KT-14-11-29 CATEE 2014: Clean Air Through Efficiency Conference, Dallas, Texas Nov. 18-20 Today’s Agenda Cities and Our Future A N A h Why Cities Need Smart...

Byrd, D.

2014-01-01

428

Star City, Russia Medical Operations  

NASA Technical Reports Server (NTRS)

Since the beginning of the NASA/Mir missions, NASA has had astronauts in training at the Gagarin Cosmonaut Training Center (GCTC), also known as Star City, with crewmembers currently there to train for the International Space Station missions. Agreements have been reached with all International Partners that allow the crewmember's parent agency to provide a flight surgeon to oversee crewmember health and safety during training away from home. NASA Medical Operations through the Bioastronautics Contract employs flight surgeons to provide medical support for U.S. crewmembers and their support staff. This poster presentation reviews the aspects of NASA medical operations at Star City.

Chandler, Michael R.; Senter, Cedric H.; Roden, Sean K.; Gilmore, Stevan; Powers, William E.; Alexander, David J.

2004-01-01

429

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

PubMed Central

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

Martínez-Romero, Esperanza

2012-01-01

430

Complete mitochondrial and plastid genomes of the green microalga Trebouxiophyceae sp. strain MX-AZ01 isolated from a highly acidic geothermal lake.  

PubMed

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

Servín-Garcidueńas, Luis E; Martínez-Romero, Esperanza

2012-11-01

431

Pre-clinical validation of a novel alpha-7 nicotinic receptor radiotracer, [(3)H]AZ11637326: target localization, biodistribution and ligand occupancy in the rat brain.  

PubMed

The alpha-7 neuronal nicotinic receptor is a novel pharmacological target for psychiatric and cognitive disorders. Selective radiotracer tools for pre-clinical receptor occupancy can facilitate the interpretation of the biological actions of small molecules at a target receptor. We discovered a high affinity nicotinic alpha-7 subtype-selective ligand, AZ11637326, with physical-chemical and pharmacokinetic properties suitable for an in vivo radioligand tool. [(3)H]AZ11637326 synthesis by tritiodehalogenation of the corresponding tribromide precursor yielded a high specific activity radiotracer with high affinity alpha-7 receptor binding in the rat hippocampus determined by autoradiography (Kd = 0.2 nM). When [(3)H]AZ11637326 was administered to rats by intravenous bolus, rapid uptake was measured in the brain followed by a 3-4 fold greater specific binding in regions containing the alpha-7 receptor (frontal cortex, hippocampus, hypothalamus and midbrain) when compared to non-target regions (striatum and cerebellum). Systemic administration of the high affinity alpha-7 receptor antagonist, methyllycaconitine (MLA), or pretreatment with alpha-7 selective agonists (AR-R17779, PyrQTC, DBCO-4-POM, and DBCO-3-POM) significantly blocked the alpha-7 specific binding of [(3)H]AZ11637326 in the rat brain. The rank order of ligand ED(50) values for in vivo alpha-7 receptor occupancy in rat hippocampus was: DBCO-4-POM > DBCO-3-POM ? MLA > PyrQTC > AR-R17779. The occupancy affinity shift was consistent with in vitro binding affinity in autoradiography. Our studies established the optimal conditions for [(3)H]AZ11637326 in vivo specific binding in the rat brain and support the use of [(3)H]AZ11637326 as a pre-clinical tool for assessment of novel alpha-7 compounds in drug discovery. PMID:21497612

Maier, Donna L; Hill, Geraldine; Ding, Min; Tuke, David; Einstein, Emily; Gurley, David; Gordon, John C; Bock, Mary J; Smith, Jeff S; Bialecki, Russell; Eisman, Mark; Elmore, Charles S; Werkheiser, Jennifer L

2011-01-01

432

Project WISH: The Emerald City  

NASA Astrophysics Data System (ADS)

Phase 3 of Project WISH saw the evolution of the Emerald City (E-City) from a collection of specialized independent analyses and ideas to a working structural design integrated with major support systems and analyses. Emphasis was placed on comparing and contrasting the closed and open cycle gas core nuclear rocket engines to further determine the optimum propulsive system for the E-City. Power and thermal control requirements were then defined and the question of how to meet these requirements was addressed. Software was developed to automate the mission/system/configuration analysis so changes dictated by various subsystem constraints could be managed efficiently and analyzed interactively. In addition, the liquid hydrogen propellant tank was statically designed for minimum mass and shape optimization using a finite element modeling package called SDRC I-DEAS. Spoke and shaft cross-sectional areas were optimized on ASTROS (Automated Structural Optimization System) for mass minimization. A structural dynamic analysis of the optimal structure also conducted using ASTROS enabled a study of the modes, frequencies, displacements, and accelerations of the E-City. Finally, the attitude control system design began with an initial mass moment of inertia analysis and was then designed and optimized using linear quadratic regulator control theory.

Oz, Hayrani; Dunne, Jim; Butchar, Stan; George, Tommy; Hellstrom, Rob; Kringen, Tricia; Owens, George; Perrea, Mike; Semeraro, Paul; Thorndike, Phil

433

The City and the Car  

Microsoft Academic Search

The social sciences have generally ignored the motor car and its awesome consequences for social life, especially in their analysis of the urban. Urban studies in particular has failed to consider the overwhelming impact of the automobile in transforming the time-space 'scapes' of the modern urban\\/suburban dweller. Focusing on forms of mobility into, across and through the city, we consider

Mimi Sheller; John Urry

2000-01-01

434

DIG Stats: City Temperature Activity  

NSDL National Science Digital Library

In this activity, students will calculate the means and standard deviations of temperature data in 5 different latitude ranges. The dataset contains the name and temperature (in degrees Fahrenheit, Celsius, and Kelvin) of each city in each range. Questions about the exercise are given. This data exists in Excel and text formats.

2004-01-01

435

Neighbourhood Inequality in Canadian Cities  

Microsoft Academic Search

In this paper, we use census tract data to analyse changes in neighbourhood income inequality and residential economic segregation in the eight largest Canadian cities during the 1980-95 period. Is the income gap between richer and poorer neighbourhoods rising? Are high and low-income families increasingly clustered in economically homogeneous neighbourhoods? The main results are an elaboration of the spatial implications

John Picot Garnett Pyper Wendy Myles; G. Picot; W. Pyper

2000-01-01

436

Great Cities Institute Faculty Scholar  

E-print Network

York Times, Wall Street Journal, Time, Chicago Tribune, Los Angeles Times, Washington Post, CNN, BBC South Peoria Street, Suite 400 Chicago, IL www.uic.edu/cuppa/gci/ For more info and to RSVP: gcities-movement social struggles in Latin America in the 1980s to street corner organizing in U.S. cities today. rough

Illinois at Chicago, University of

437

Fiat electric city car prototype  

Microsoft Academic Search

Electric vehicles represent an important research activity. One of the themes was the development of a two city car prototype with property designed body. The main purpose was to define a vehicle capable of meeting the multiple requirements of a comfortable and easy driving - handling - parking, and suitable performance for urban operation in level or hilly routes. The

G. Brusaglino

1978-01-01

438

Cities, Skills and Regional Change  

Microsoft Academic Search

Glaeser E. L., Ponzetto G. A. M. and Tobio K. Cities, skills and regional change, Regional Studies. One approach to urban areas emphasizes the existence of certain immutable relationships, such as Zipf's or Gibrat's law. An alternative view is that urban change reflects individual responses to changing tastes or technologies. This paper examines almost 200 years of regional change in

Edward L. Glaeser; Giacomo A. M. Ponzetto; Kristina Tobio

2012-01-01

439

Dublin City University Educational Trust  

E-print Network

is evidenced by the transformation of the original site to a modern purpose-built campus. Indeed, nearly every of the DCU Educational Trust's activities and funding. OUR MISSION AND HISTORY #12;#12;Dublin City University is like planting a tree ­ the gift is invested and a portion of earned interest permanently generates

Humphrys, Mark

440

Budgets and Big City Education.  

ERIC Educational Resources Information Center

The prospect of simultaneous cuts in Federal and State aid to public school education in some States poses a serious threat to large cities which suffer financial stress and face the added responsibility of educating large numbers of poor black and Hispanic children. Financial needs that might result from cuts in Federal aid cannot be met by State…

Orfield, Gary

441

Project WISH: The Emerald City  

NASA Technical Reports Server (NTRS)

Phase 3 of Project WISH saw the evolution of the Emerald City (E-City) from a collection of specialized independent analyses and ideas to a working structural design integrated with major support systems and analyses. Emphasis was placed on comparing and contrasting the closed and open cycle gas core nuclear rocket engines to further determine the optimum propulsive system for the E-City. Power and thermal control requirements were then defined and the question of how to meet these requirements was addressed. Software was developed to automate the mission/system/configuration analysis so changes dictated by various subsystem constraints could be managed efficiently and analyzed interactively. In addition, the liquid hydrogen propellant tank was statically designed for minimum mass and shape optimization using a finite element modeling package called SDRC I-DEAS. Spoke and shaft cross-sectional areas were optimized on ASTROS (Automated Structural Optimization System) for mass minimization. A structural dynamic analysis of the optimal structure also conducted using ASTROS enabled a study of the modes, frequencies, displacements, and accelerations of the E-City. Finally, the attitude control system design began with an initial mass moment of inertia analysis and was then designed and optimized using linear quadratic regulator control theory.

Oz, Hayrani; Dunne, Jim; Butchar, Stan; George, Tommy; Hellstrom, Rob; Kringen, Tricia; Owens, George; Perrea, Mike; Semeraro, Paul; Thorndike, Phil

1992-01-01

442

A Tale of Two Cities  

ERIC Educational Resources Information Center

This is a report of two inner city school systems which are following new approaches to increase pupil's reading skills and academic achievement. The experiences to date of the Washington, D.C., Board of Education with the Reading Mobilization Year, and those of the Gary, Ind., Board of Education and the Behavioral Research Laboratories are…

Reading Newsreport, 1970

1970-01-01

443

Sioux City Riverbank Filtration Study  

NASA Astrophysics Data System (ADS)

The City of Sioux City (City) obtains a large percentage of their drinking water supply from both a horizontal collector well system and vertical wells located adjacent to the Missouri River. These wells are set in either the Missouri Alluvium or the Dakota Sandstone aquifer. Several of the collector well laterals extend out beneath the Missouri River, with the laterals being over twenty feet below the river channel bottom. Due to concerns regarding ground water under direct surface water influence, the Iowa Department of Natural Resources (IDNR) required the City to expand their water treatment process to deal with potential surface water contaminant issues. With the extensive cost of these plant upgrades, the City and Olsson Associates (OA) approached the IDNR requesting approval for assessing the degree of natural riverbank filtration for water treatment. If this natural process could be ascertained, the level of treatment from the plant could be reduced. The objective of this study was to quantify the degree of surface water (i.e. Missouri River) filtration due to the underlying Missouri River sediments. Several series of microscopic particulate analysis where conducted, along with tracking of turbidity, temperature, bacteria and a full scale particle count study. Six particle sizes from six sampling points were assessed over a nine-month period that spanned summer, fall and spring weather periods. The project was set up in two phases and utilized industry accepted statistical analyses to identify particle data trends. The first phase consisted of twice daily sample collection from the Missouri River and the collector well system for a one-month period. Statistical analysis of the data indicated reducing the sampling frequency and sampling locations would yield justifiable data while significantly reducing sampling and analysis costs. The IDNR approved this modification, and phase II included sampling and analysis under this reduced plant for an eight-month period. Final statistical analyses of the nine months of data indicate up to a four-log particle reduction occurs through river bank filtration. Consequently, Missouri River sediments within the City's well field are very effective in water filtration. This information was submitted to the IDNR for review and approval. Subsequently, the IDNR approved 4.0 log removal for Giardia and 3.5 log removal for Cryptosporidium through the riverbank and treatment plant. The City and IDNR have agreed on subrogate parameters for monitoring purposes.

Mach, R.; Condon, J.; Johnson, J.

2003-04-01

444

Ultra Fine-Grained AZ31 Magnesium Alloy Obtained by a Combination of Grain Refinement and Equal Channel Angular Pressing  

NASA Astrophysics Data System (ADS)

Different amounts of Al-5Ti-1B master alloy (TiBAl) were added to the AZ31 magnesium alloy (Mg-3Al-1Zn-0.2Mn) as grain refiner and the resulting microstructure and grain size distributions were studied after extrusion and equal channel angular pressing (ECAP). Results showed that the addition of 0.6% TiBAl had the strongest grain refinement effect, reducing the grain sizes by 54.5 and 48.5% in the extruded and ECAPed conditions, respectively. The observed grain refinement was partly due to the presence of the thermally-stable micron- and submicron-sized particles in the melt which act as nucleation sites during solidification. During the high-temperature extrusion and ECAP processes, dynamic recrystallization (DRX) and grain growth are likely to occur. However, the mentioned particles will help in reducing the grain size by the particle stimulated nucleation (PSN) mechanism. Furthermore, the pinning effect of these particles can oppose grain growth by reducing the grain boundary migration. These two phenomena together with the partitioning of the grains imposed by the severe plastic deformation in the ECAP process have all contributed to the achieved ultrafine-grained structure in the AZ31 alloy.

Torbati-Sarraf, S. A.; Mahmudi, R.

445

A New Constitutive Model for AZ31B Magnesium Alloy Sheet Deformed at Elevated Temperatures and Various Strain Rates  

NASA Astrophysics Data System (ADS)

In this study, a new constitutive model is established for AZ31B magnesium alloy sheet at elevated temperatures and strain rates in order to describe two competing mechanisms for deformation, i.e. both work-hardening and softening stage of AZ31B magnesium alloy sheet. Stress-strain curves obtained by conducting uni-axial tensile tests at elevated and strain rates were first separated at the maximum stress and corresponding strain values. Voce's law [25] was then employed to fit separated hardening and softening stage. A MATLAB tool is used to determine material parameters by using least square fitting method at various temperatures and strain rate. The mergence of separated work-hardening and softening equations is in good agreement with experimental data. The parameters of fitting curves are utilized to determine them as a function of temperature and strain rate using a surface fitting method. The final equation is then implemented to predict stress-strain curves at various temperatures and strain rates. The proposed equation showed the good comparability between the simulation results and the corresponding experiments.

Nguyen, Duc-Toan

2014-12-01

446

Iron Phosphate Glass for Vitrifying Hanford AZ102 LAW in Joule Heated and Cold Crucible Induction Melters - 12240  

SciTech Connect

An iron phosphate composition for vitrifying a high sulfate (?17 wt%) and high alkali (?80 wt%) Hanford low activity waste (LAW), known as AZ-102 LAW, has been developed for processing in a Joule Heated Melter (JHM) or a Cold Crucible Induction Melter (CCIM). This composition produced a glass waste form, designated as MS26AZ102F-2, with a waste loading of 26 wt% of the AZ-102 which corresponded to a total alkali and sulfate (represented as SO{sub 3}) content of 21 and 4.4 wt%, respectively. A slurry (7 M Na{sup +}) of MS26AZ102F-2 simulant was melted continuously at temperatures between 1030 and 1090 deg. C for 10 days in a small JHM at PNNL and for 70 hours in a CCIM at INL. The as-cast glasses produced in both melters and in trial laboratory experiments along with their canister centerline cooled (CCC) counterparts met the requirements for the Product Consistency Test (PCT) and the Vapor Hydration Test (VHT) responses in the Hanford Tank Waste Treatment and Immobilization Plant (WTP) Contract. These glass waste forms retained up to 77 % of the SO{sub 3} (3.3 wt%), 100% of the Cesium, and 33 to 44% of the rhenium (used as a surrogate for Tc) all of which either exceeded or were comparable to the retention limit for these species in borosilicate glass nuclear waste form. Analyses of commercial K-3 refractory lining and the Inconel 693 metal electrodes used in JHM indicated only minimum corrosion of these components by the iron phosphate glass. This is the first time that an iron phosphate composition was melted continuously in a slurry fed JHM and in the US, thereby, demonstrating that iron phosphate glasses can be used as alternative hosts for vitrifying nuclear waste. The following conclusions are drawn from the results of the present work. (1) An iron phosphate composition, designated as MS26AZ102F-2, containing 26 wt% of the simulated high sulfate (17 wt%), high alkali (80 wt%) Hanford AZ-102 LAW meets all the criteria for processing in a JHM and CCIM. This composition produces a homogeneous glass with a density of 2.80 ą 0.04 g/cm{sup 3} after melting between 1000 and 1050 deg. C for 3 to 5 h. (2) This is the first time that an iron phosphate glass was melted in the JHM continuously for 10 days achieving a specific melting rate of 1010 kg/m2/day and in the CCIM for 70 hrs with a melting rate of 664 kg/m{sup 2}/day. (3) The analyzed (ICP-AES) compositions for all the glasses prepared under several melting conditions are in excellent agreement with the target composition. The variation of melting conditions include: (i) use of small scale/short melting time to large scale/long melting time (300 g to 80 kg, 4 h to 10 days) operations including melting in the JHM and CCIM, (ii) use of dry or wet (slurry) melter feed, (iii) addition of reductant (sugar) in the batch, and (iv) bubbling the melt with air. (4) The chemical durability as measured by PCT and VHT for the quenched and CCC-treated waste forms prepared from laboratory, JHM or CCIM melting exceeds the DOE requirements for LAW. (5) Depending upon the melting time (4 h to 10 days), the average concentration of SO{sub 3} in the MS26AZ102F-2 iron phosphate glass waste form varies from about 1.78 (RSM) to 3.74 (laboratory melt) wt% which corresponds to an SO{sub 3} retention of 41 to 86% when melted between 1030 at 1050 deg. C in air. (6) The retention of SO{sub 3} in the glass was reduced when a reductant (sugar) was added to the slurry. (7) The retention of other problem components like Cesium and Rhenium/Tc-99 is also high; from 92 to 100% for Cs{sub 2}O under different melting conditions, and from 66 to 33% for Re{sub 2}O{sub 7} for melts processed from 3 to 5 hours and up to 10 days. (8) Corrosion tests on Inconel 693 and K-3 refractory at temperatures between 1000 and 1050 deg. C indicate that both materials should be suitable for melting iron phosphate glasses. (9) The viscosity and electrical conductivity of the MS26AZ102F-2 melt are within the acceptable limits for RSM and CCIM processing. (10)This work has shown that iron phosphate compositions are a pot

Day, Delbert E.; Brow, Richard K.; Ray, Chandra S.; Reis, Signo T. [Missouri University of Science and Technology, 1870 Miner Circle, Rolla, MO 65409 (United States); Kim, Cheol-Woon [MO-SCI Corporation, 4040 HyPoint North, Rolla, MO 65401 (United States); Vienna, John D.; Sevigny, Gary [Pacific North West National Laboratory, Battelle Blvd., Richland, WA 99352 (United States); Peeler, David; Johnson, Fabienne C.; Hansen, Eric K. [Savannah River National Laboratory, Savannah River Site, 999-W, Aiken, SC 29803 (United States); Soelberg, Nick [Idaho National Laboratory, 2525 Fremont Avenue, Idaho Falls, ID 83415 (United States); Pegg, Ian L.; Gan, Hao [Catholic University of America, 620 Michigan Avenue, N.E., Washington, DC 20064 (United States)

2012-07-01

447

Studies on influence of zinc immersion and fluoride on nickel electroplating on magnesium alloy AZ91D  

NASA Astrophysics Data System (ADS)

The effect of zinc immersion and the role of fluoride in nickel plating bath were mainly investigated in nickel electroplating on magnesium alloy AZ91D. The state of zinc immersion, the composition of zinc film and the role of fluoride in nickel plating bath were explored from the curves of open circuit potential (OCP) and potentiodynamic polarization, the images of scanning electron microscopy (SEM) and the patterns of energy dispersive X-ray (EDX). Results show that the optimum zinc film mixing small amount of Mg(OH) 2 and MgF 2 is obtained by zinc immersion for 30-90 s. The corrosion potential of magnesium alloy substrate attached zinc film will be increased in nickel plating bath and the quantity of MgF 2 sandwiched between magnesium alloy substrate and nickel coating will be reduced, which contributed to produce nickel coating with good performance. Fluoride in nickel plating bath serves as an activator of nickel anodic dissolution and corrosion inhibitor of magnesium alloy substrate. 1.0-1.5 mol dm -3 of F - is the optimum concentration range for dissolving nickel anode and protecting magnesium alloy substrate from over-corrosion in nickel plating bath. The nickel coating with good adhesion and high corrosion resistance on magnesium alloy AZ91D is obtained by the developed process of nickel electroplating. This nickel layer can be used as the rendering coating for further plating on magnesium alloys.

Zhang, Ziping; Yu, Gang; Ouyang, Yuejun; He, Xiaomei; Hu, Bonian; Zhang, Jun; Wu, Zhenjun

2009-06-01

448

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

NASA Astrophysics Data System (ADS)

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.

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

2013-09-01

449

Great Zoom out of Tucson, AZ: The University of Arizona Football Stadium  

NSDL National Science Digital Library

Using data from different spacecraft and some powerful computer technology, visualizers at the Goddard Space Flight Center present you with a collection of American cities in a way you have never seen them before. Starting with our camera high above the Earth, we rush in towards the surface at what would be an impossible speed for any known vehicle. Passing though layers of atmosphere, the colors of our destinations shimmer with their own unique characteristics, and suddenly we find ourselves floating in virtual space just above the ground.

Shirah, Greg; Mitchell, Horace; Newcombe, Marte; Williams, Darrel

2001-09-06

450

Great Zoom into Tucson, AZ: The University of Arizona Football Stadium  

NSDL National Science Digital Library

Using data from different spacecraft and some powerful computer technology, visualizers at the Goddard Space Flight Center present you with a collection of American cities in a way you have never seen them before. Starting with our camera high above the Earth, we rush in towards the surface at what would be an impossible speed for any known vehicle. Passing though layers of atmosphere, the colors of our destinations shimmer with their own unique characteristics, and suddenly we find ourselves floating in virtual space just above the ground.

Shirah, Greg; Mitchell, Horace; Newcombe, Marte; Williams, Darrel

2001-09-06

451

49 CFR 372.221 - Twin Cities.  

Code of Federal Regulations, 2013 CFR

...Transportation 5 2013-10-01 2013-10-01 false Twin Cities. 372.221 Section 372.221 Transportation...ZONES, AND TERMINAL AREAS Commercial Zones § 372.221 Twin Cities. For the purpose of determining commercial...

2013-10-01

452

49 CFR 372.221 - Twin Cities.  

Code of Federal Regulations, 2012 CFR

...Transportation 5 2012-10-01 2012-10-01 false Twin Cities. 372.221 Section 372.221 Transportation...ZONES, AND TERMINAL AREAS Commercial Zones § 372.221 Twin Cities. For the purpose of determining commercial...

2012-10-01

453

49 CFR 372.221 - Twin Cities.  

Code of Federal Regulations, 2014 CFR

...Transportation 5 2014-10-01 2014-10-01 false Twin Cities. 372.221 Section 372.221 Transportation...ZONES, AND TERMINAL AREAS Commercial Zones § 372.221 Twin Cities. For the purpose of determining commercial...

2014-10-01

454

49 CFR 372.221 - Twin Cities.  

Code of Federal Regulations, 2011 CFR

...Transportation 5 2011-10-01 2011-10-01 false Twin Cities. 372.221 Section 372.221 Transportation...ZONES, AND TERMINAL AREAS Commercial Zones § 372.221 Twin Cities. For the purpose of determining commercial...

2011-10-01

455

Water rites : a city stage for Boston  

E-print Network

This thesis focuses on the design of a public theatre for the entire city of Boston, a "city stage." The intention is to explore through design the boundaries of an architectural setting for large scale performance art; ...

Mansfield, Timothy Denton

1990-01-01

456

The casino in the communist city  

E-print Network

The casino in the communist city is a contentious place of hidden desires, perceived debauchery and luxury. Accessible only to foreign passport holders, casinos in Ho Chi Minh City (formerly known required by law to be ...

Tran, Jennifer, M. Arch. Massachusetts Institute of Technology

2008-01-01

457

Adaptation: Cities' response to climate risks  

NASA Astrophysics Data System (ADS)

City-level policies have often been unable to limit natural disaster losses. Research on New York City now shows progress in devising flexible adaptation policies that accept uncertainty about future climate-related risks and work around it.

Aerts, Jeroen; Botzen, Wouter

2014-09-01

458

Computing the Image of the City  

E-print Network

Kevin Lynch proposed a theory of the image of the city identifying five elements that make the city legible or imageable. The resulting mental map of the city was conventionally derived through some qualitative processes, relying on interactions with city residents to ask them to recall city elements from their minds. This paper proposes a process by which the image of the city can be quantitatively derived automatically using computer technology and geospatial databases of the city. This method is substantially based on and inspired by Christopher Alexander's living structure and Nikos Salingaros' structural order, as a city with the living structure or structural order tends to be legible and imageable. With the increasing availability of geographic information of urban environments at very fine scales or resolutions (for example, trajectories data about human activities), the proposal or solution described in this paper is particularly timely and relevant for urban studies and architectural design. Keyword...

Jiang, Bin

2012-01-01

459

Synthetic ecology : revisiting Mexico City's lakes project  

E-print Network

Mexico City was founded 700 years ago on man made islets in the middle of a lake. Today, it faces a contradictory situation were water is running scarce, but simultaneously the city runs the risk of drowning in its own ...

Daou, Daniel (Daou Ornelas)

2011-01-01

460

Clean Cities Program Contacts (Fact Sheet)  

SciTech Connect

This fact sheet provides contact information for program staff of the U.S. Department of Energy's Clean Cities program, as well as contact information for the nearly 100 local Clean Cities coalitions across the country.

Not Available

2012-03-01

461

Kansas City`s Union Station redevelopment opportunity -- Environmental challenges  

SciTech Connect

Kansas City`s Union Station, located at the center of a 1.7 million metropolitan population, is the second largest train station in the United States. The Station ceased to operate as a train station in 1983 and has since been falling into an increasing state of disrepair. This paper provides an insight into ``brownfield`` redevelopment and renovation for adaptive reuse of major turn of the century facilities such as Union Station. Substantial assessment and investigation activities have been conducted at Union Station for compliance and corrective action under RCRA, TSCA, and associated state regulations encompassing remediation estimated at more than $3 million. Recognized environmental conditions identified at Union Station included potential underground storage tanks; solid wastes, special wastes, and potentially hazardous wastes located inside the building; free liquids in sumps and elevator pits; asbestos-containing materials; lead-based paint; and potential for soil contamination on the surrounding property.

Snyder, M.G. [Black and Veatch Waste Science, Inc., Overland Park, KS (United States); Scott, A. [Union Station Assistance Corp., Kansas City, MO (United States)

1995-12-31

462

Extreme Rainfall In A City  

NASA Astrophysics Data System (ADS)

Cities contain many structures and activities that are vulnerable to severe weather. Heavy precipitation cause floods which can damage structures, compromise transportation and water supply systems, and slow down economic and social activities. Rain induced flood patterns in cities must be well understood to enable effective placement of flood control and other regulatory measures. The planning goal is not to eliminate all floods but to reduce their frequency and resulting damage. Possible approaches to such planning include probability based extreme event analysis. Precipitation is normally the most variable hydrologic element over a given area. This variability results from the distribution of clouds and in cloud processes in the atmosphere, the storm path, and the distribution of topographical features on the ground along path. Some studies suggest that point rainfall patterns are also affected by urban industrial effects hence some agreement that cities are wetter than the country surrounding them. However, there are still questions regarding the intra- urban distribution of precipitation. The sealed surfaces, urban structures, and the urban heat anomaly increase convection in cities which may enhance the generation of clouds. Increased dust and gaseous aerosols loads are effective condensation and sublimation nuclei which may also enhance the generation of precipitation. Based on these associations, the greatest amount of convection type rainfall should occur at city center. A study of summer rainfall in Calgary showed that frequencies of trace amounts of rainfall and events under 0.2mm are highest downtown than elsewhere. For amounts greater than than 0.2 mm, downtown sites were not favored. The most compelling evidence for urban-industrial precipitation enhancement came from the Metromex project around St. Loius, Missouri where maximum increases of between 5 to 30 per cent in summer rainfall downwind of the city was linked to urbanization and industrialization. The development of small cloud droplets into larger particles requires time. A single thunderstorm cell has a mean development time of about 20 minutes and a life time of around 45 minutes with a mean mind of 10m/s, an air parcel would travel 12 km from the beginning of droplet formation to the first precipitation. That means that the precipitation field is shifted downwind of settlements. It could also explain the the higher frequency of the trace to small amounts observed in Calgary since those events occur under relatively calm weather. Whereas the majority of studies have focused on summer convectional type events, little appears to have been done on the extreme rainfall events on which most structural designs are based. Is there a detectable urban bias in these events? Do urban areas intensify them? What are the implications of point distribution of extreme rainfall events on flood frequency across a city. This paper examines the spatial distribution of the mean annual maximum rainfall event in Calgary, Canada, with a view to determining the relative contribution of geographical setting and urbanisation to point patterns. The data are subsequently maximized to produce maps of probable maximum precipitation for the city. The major results are as follows: (a) position along storm path is the most important variable determining maximum rainfall hazard, (b) higher grounds receive up to seventy percent more maximum rainfall than values based on spatial trend, (c) urban structure and geometry correlate negatively with maximum rainfall intensity, however, (d) zones of maximum flood peaks are found down slope of areas of maximum precipitation increasing flood hazard in the inner city in spite of its lower precipitation. Drainage networks based on point rainfall patterns have proved grossly inadequate for flood mitigation. The new design based on this study recognizes the strong moisture gradients caused by rapid movement of water and other elements down slope. Snow and river flow hazards reflect similar environmental controls.

Nkemdirim, Lawrence

463

City of Sonoma No. 1 The Plaza  

E-print Network

City of Sonoma No. 1 The Plaza Sonoma California 95476-6690 Phone (707) 938-3681 Fax (707) 938 Sacramento, Ca 95814-5514 Re: City of Sonoma Amendments to 2010 CALGreen and the Building Energy Efficiency to have the City of Sonoma enforce the current Title 24 Building Energy Efficiency Standards as part

464

7, 66876718, 2007 Mexico City area  

E-print Network

Discussions Emissions from forest fires near Mexico City R. Yokelson1 , S. Urbanski2 , E. Atlas3 , D. Toohey4 the mountains surrounding Mexico City (MC) are about 2 times higher than normally observed for forest burningACPD 7, 6687­6718, 2007 Mexico City area mountain fires R. Yokelson et al. Title Page Abstract

Boyer, Edmond

465

Creating Smart-er Cities: An Overview  

ERIC Educational Resources Information Center

The following offers an overview of what it means for cities to be "smart." It draws the supporting definitions and critical insights into smart cities from a series of papers presented at the 2009 Trans-national Conference on Creating Smart(er) Cities. What the papers all have in common is their desire to overcome the all too often…

Allwinkle, Sam; Cruickshank, Peter

2011-01-01

466

City of Manhattan Beach Community Development  

E-print Network

City of Manhattan Beach Community Development Phone: (310) 802-5500 FAX: (310) 802-5501 TDD: (310 Sacramento, Ca. 95814 Attention: Joe Loyer j mloycr@cncrgy.stalc.ca.us Subject: City of Manhattan Beach the City of Manhattan Beach adoption of our local more stringent energy efficiency standards. In accordance

467

Black Visibility, City Size, and Social Control  

Microsoft Academic Search

The research reported in this article tests the hypothesis that the relationship between the public fiscal commitment to policing and minority group size is not the same in small cities as it is in large cities. The results of a comparison of all cities in the United States that were greater than 50,000 in population in 1970 with those that

Pamela Irving jackson

1986-01-01

468

Adaptive Information Cluster Dublin City University  

E-print Network

Adaptive Information Cluster Dublin City University Hyowon Lee Adaptive Information Cluster, Dublin City University, Glasnevin, Dublin 9 Email: hlee@computing.dcu.ie Daragh Byrne Adaptive Information Cluster, Dublin City University, Glasnevin, Dublin 9 Email: dbyrne@computing.dcu.ie SinĂŠad Mc Givney

Lee, Hyowon

469

NATIONAL COOPERATIVE INNER CITY ASTHMA STUDY (NCICAS)  

EPA Science Inventory

National Cooperative Inner City Asthma Study (NCICAS) Phase I is to identify factors responsible for the rise in asthma among inner-city children aged 4-9 years. NCICAS Phase II is an intervention study aimed at reducing the asthma morbidity of inner city children aged 5-11 years...

470

Twin Cities Metro Advanced Practice Center  

E-print Network

Twin Cities Metro Advanced Practice Center Food Safety Self Inspection Checklist #12;Table-20 Vietnamese..............................21-22 #12;Food Safety Self Inspection Checklist Twin Cities Metro has expired. #12;Food Safety Self Inspection Checklist Twin Cities Metro Advanced Practice Center

471

City Schools: Lessons from New York.  

ERIC Educational Resources Information Center

This book presents a collection of essays by researchers and educators that examine the largest school system in the U.S.--the New York City school system. There are 5 parts with 15 chapters. Part 1, "Education in the City," includes: (1) "Schooling in New York City: The Socioeconomic Context" (Emanuel Tobier) and (2) "Public Schools That Work"…

Ravitch, Diane, Ed.; Viteritti, Joseph P., Ed.

472

STANFORD REDWOOD CITY INFUSION THERAPY CENTER  

E-print Network

STANFORD REDWOOD CITY INFUSION THERAPY CENTER Stanford Redwood City Infusion Therapy Center 450 that the new Stanford Redwood City Infusion Therapy Center opened on January 6, 2014. This new state previously received infusion treatments in the Infusion Treatment Area (ITA) at the Stanford Cancer Center

Bejerano, Gill

473

1951 KANSAS CITY FLOOD LEXINGTON GROUP  

E-print Network

1951 KANSAS CITY FLOOD LEXINGTON GROUP KANSAS CITY, MO OCTOBER 24, 2013 JOHN W. BARRIGER IV #12 ¡ ACTION TO PREVENT REOCCURRENCE #12;¡ SITUATION IN KANSAS AND MISSOURI ¡ DETOUR AT OLATHE ¡ ARMY CORPS Kansas State Historical Society Kansas City Public Library BSNF PERSONS WHO ASSISTED IN SECURING PHOTOS

Bustamante, FabiĂĄn E.

474

university of The City and Your University  

E-print Network

, health and leisure ­ facilities for the City 10 Helping the City's young people 13 Caring for our City;1 A Welcome from the Lord Mayor of Exeter I welcome this chance for the people of Exeter to find out more, treating employees fairly and with respect. ¡ Top University. Exeter was voted University of the Year 2007

Mumby, Peter J.

475

Zipf'S Law For Cities: An Explanation  

Microsoft Academic Search

Zipf's law is a very tight constraint on the class of admissible models of local growth. It says that for most countries the size distribution of cities strikingly fits a power law: the number of cities with populations greater than S is proportional to 1\\/S. Suppose that, at least in the upper tail, all cities follow some proportional growth process

Xavier Gabaix

1999-01-01

476

Competition among Cities with Density Levels  

Microsoft Academic Search

Abstract This paper considers the strategic adoption of density levels to control and guide urban growth in a closed system of cities. The density level in each city (negatively) aects,the utility of resident households. The main distinction with respect to related literature is that it allows for the possibility of adjustment of variables such as the sizes of the cities

Dolores Garcia; Ricard Torres

477

The city and its need for technology  

NASA Technical Reports Server (NTRS)

An experimental program has been undertaken to explore the process of identifying and transferring newer technology for the benefit of the city. This paper describes the nature of the problems involved in the experiment, some of the areas of supposed commonality with other cities and some of the prerequisites for any city to become involved with technological innovation.

Berkowitz, B. L.

1978-01-01

478

City of College Station's Thermographic Mobile Scan  

E-print Network

During the first quarter of 1986, the City of College Station conducted a thermographic mobile scan of the entire city. A thermographic mobile scan is a process by which heat loss/heat gain data is accumulated by a vehicle traveling the city...

Shear, C. K.

1986-01-01

479

49 CFR 372.221 - Twin Cities.  

Code of Federal Regulations, 2010 CFR

...Delmar, Del-Md. (5) Harrison, Ohio-West Harrison, Ind. (6) Junction City, Ark.-La. (7) Kansas City...Tex. (11) Texhoma, Tex.-Okla. (12) Union City, Ind.-Ohio. [41 FR 56654, Dec. 29, 1976, as amended...

2010-10-01

480

2000 2006 City Percentage Point Change  

E-print Network

used for cities of Benton Harbor, Grand Haven and Monroe Source: Michigan Office of Labor Market2000 2006 City Percentage Point Change County Average 2000 County Average 2006 City vs. County 2006 Information Unemployment Rates, 2000 and 2006 Percentage of Labor Force Percentage Point Difference -4.0 -3

Baskaran, Mark

481

A Status Report on Children in America's Cities: A 52-City Survey.  

ERIC Educational Resources Information Center

A survey of officials in 52 cities in the United States gathered information on the conditions and issues relating to urban children, on how city governments are structured to respond to those needs, and on city programs and initiatives which benefit children. Information provided by the cities was supplemented by data from the Bureau of the…

United States Conference of Mayors, Washington, DC.

482

Epigenetic regulation of the ribosomal cistron seasonally modulates enrichment of H2A.Z and H2A.Zub in response to different environmental inputs in carp (Cyprinus carpio)  

PubMed Central

Background The specific deposition of histone variants into chromatin is an important epigenetic mechanism that contributes to gene regulation through chromatin architectural changes. The histone variant H2A.Z is essential in higher eukaryotes, and its incorporation within chromatin is a relevant process for gene expression and genome stability. However, the dual positive and negative roles of H2A.Z in gene regulation still remain unclear. We previously reported that acclimatization in common carp fish (Cyprinus carpio) involves cyclical seasonal gene reprogramming as an adaptation response to its natural environment, when rRNA synthesis and processing are profoundly affected. Epigenetic mechanisms primarily contribute to the transcriptional modulation of ribosomal genes concomitant with the acclimatization process, thus significantly regulating this process. The aim of this study was to describe the presence of several H2A.Z subtypes in carp, and assess the role of H2A.Z on the ribosomal cistron in summer- and winter-acclimatized carp. Results This paper reports for the first time about the transcriptional expression of four different H2A.Z subtypes belonging to the same organism. Remarkably, a novel H2A.Z.7 was found, which corresponds to a tissue-specific histone subtype that contains seven amino acid residues longer than the canonical H2A.Z. Moreover, H2A.Z enrichment through the ribosomal cistron was significantly higher during summer, when rRNA transcription and processing are highly active, than it was in winter. Similar patterns of H2A.Z enrichment are found in two seasonally active promoters for genes transcribed by RNA polymerase II, the L41 and ?9-desaturase genes. Interestingly, ubiquitylated-H2A.Z (H2A.Zub) was strongly enriched on regulatory regions of the ribosomal cistron in summer-acclimatized carp. Additionally, H2A.Z was present in both heterochromatin and euchromatin states on ribosomal cistron and RNA polymerase II promoters. Conclusions Our study revealed seasonally-dependent H2A.Z enrichment for active ribosomal cistron and RNA polymerase II promoters during the carp environmental adaptation. Moreover, seasonal H2A.Zub enrichment appears as a specific mechanism contributing to the regulation of chromatin architecture under natural conditions. The existence of several H2A.Z subtypes in carp suggests that the epigenetic regulation in this species constitutes a complex and finely tuned mechanism developed to cope with seasonal environmental changes that occur in its habitat. PMID:23866978

2013-01-01

483

Urban Heat Islands: Hotter Cities  

NSDL National Science Digital Library

The issue-focused, peer-reviewed article demonstrates how as cities add roads, buildings, industry, and people heat islands are created in urban areas. Some consequences include:human discomfort and sometimes human health risks, increase in energy use, leading to release of more greenhouse gases, air pollution and increased levels of urban ozone, and higher costs because of greater water and energy use.

Urban Heat Islands (University of Western Ontario;)

2004-11-01

484

City University of New York  

NSDL National Science Digital Library

The City University of New York, New York, USA contains the 19 CUNY colleges. Offers previews of multimedia programs developed by CUNY faculty and links to an innovative gopher containing resources for teaching English as a second language. Featured in the CUNY Multimedia Development Initiative page is "The Art of Renaissance Science," a prototype hypermedia article that explores the interconnections between art and science in Renaissance Italy.

485

City Botanical Gardens Parliament House  

E-print Network

No City Botanical Gardens Parliament House R I V E R S I D E B I C Y C L E PAT H TEERTSECILA EGDIRBLLIWDOOG Registrar's Garden to River Stage R I VE R S I D E E X P R E S S W AY KENNEDY WAY NORMAN WAY MUSGRAVELANE BLACKALLLANE MACGREGORLANE LAMINGTON DRIVE GARDENS POINT ROAD Old Government House Podium QUT Art

Mayer, Wolfgang

486

The “Thermodynamics” of the City  

Microsoft Academic Search

\\u000a The primary objectives of this chapter are twofold: first, to offer a review of progress in urban modelling using the methods\\u000a of statistical mechanics; and second, to explore the possibility of using the thermodynamic analogy in addition to statistical mechanics. We can take stock of the “thermodynamics of the city” not in the sense of its\\u000a physical states – interesting

Alan Wilson

487

Why Register to Vote in AZ? Are you studying at ASU? If you are over 18 years old, reside in Arizona, are a U.S.  

E-print Network

in Arizona, are a U.S. citizen and don't have recent felonies you qualify to register to vote in this stateWhy Register to Vote in AZ? Are you studying at ASU? If you are over 18 years old, reside impacts you but also thousands of other students and millions of people.Your vote counts! #12;

Hall, Sharon J.

488

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

SciTech Connect

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.

Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito, Ibaraki 310-8512 (Japan); Hiramatsu, Masaaki [Academia Sinica Institute of Astronomy and Astrophysics, Taiwan (China); Tsukagoshi, Takashi [Institute of Astronomy, Faculty of Science, University of Tokyo (Japan); Shimajiri, Yoshito; Ezawa, Hajime; Kawabe, Ryohei [Nobeyama Radio Observatory, NAOJ (Japan); Ikeda, Norio; Kitamura, Yoshimi; Kamegai, Kazuhisa [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (Japan); Saito, Masao [ALMA Project Office, NAOJ (Japan)

2009-08-05

489

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? ...

490

8. Simplification of the Equations of Hooke's Law 15 In these equations a..{ ay,az) is the normal stress acting on a plane  

E-print Network

¡ 8. Simplification of the Equations of Hooke's Law 15 In these equations a..{ ay,az) is the normal as coefficients of elasticity. 8. Simplification of the Equations of Hooke's Law as a Consequence of Crystal Symmetry The equations expressing Hooke's law can be greatly simplified if the symmetry of crystals

Cambridge, University of

491

RACEMIZATION OF METEORITIC AMINO ACIDS. B. A. Cohen1 and C. F. Chyba, The University of Ari-zona, Tucson AZ 85719 1bcohen@lpl.arizona.edu.  

E-print Network

RACEMIZATION OF METEORITIC AMINO ACIDS. B. A. Cohen1 and C. F. Chyba, The University of Ari- zona, Tucson AZ 85719 1bcohen@lpl.arizona.edu. Amino acids are the building blocks of proteins, among the most biologically critical molecules. It was first noted in the 1800's that the vast majority of amino acids used

Cohen, Barbara Anne

492

Effect of interlayer configurations on joint formation in TLP bonding of Ti-6Al-4V to Mg-AZ31  

NASA Astrophysics Data System (ADS)

In this research work, the transient liquid phase (TLP) bonding process was utilized to fabricate joints using thin (20?m) nickel and copper foils placed between two bonding surfaces to help facilitate joint formation. Two joint configurations were investigated, first, Ti-6Al-4V/CuNi/Mg-AZ31 and second, Ti-6Al-4V/NiCu/Mg-AZ3L The effect of bonding time on microstructural developments across the joint and the changes in mechanical properties were studied as a function of bonding temperature and pressure. The bonded specimens were examined by metallographic analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD). In both cases, intermetallic phase of CuMg2 and Mg3AlNi2 was observed inside the joint region. The results show that joint shear strengths for the Ti-6Al-4V/CuNi/Mg-AZ31 setup produce joints with shear strength of 57 MPa compared to 27MPa for joints made using the Ti-6Al-4V/NiCu/Mg-AZ31 layer arrangement.

Atieh, A. M.; Khan, T. I.

2014-06-01

493

In Proceedings of the International Conference on Modeling and Analysis of Semiconductor Manufacturing, Arizona State University, Tempe, AZ, USA, May, 2000.  

E-print Network

Manufacturing, Arizona State University, Tempe, AZ, USA, May, 2000. HIGH-FIDELITY RAPID PROTOTYPING OF THE REAL manufacturing in- dustry has been driven by continuous technological advancement of the underlying production results in Dis- crete Event Systems theory. Furthermore, in addition to the development of the formal

494

Cryogenic machining and burnishing of AZ31B magnesium alloy for enhanced surface integrity and functional performance  

NASA Astrophysics Data System (ADS)

Surface integrity of manufactured components has a critical impact on their functional performance. Magnesium alloys are lightweight materials used in the transportation industry and are also emerging as a potential material for biodegradable medical implants. However, the unsatisfactory corrosion performance of Mg alloys limits their application to a great extent. Surface integrity factors, such as grain size, crystallographic orientation and residual stress, have been proved to remarkably influence the functional performance of magnesium alloys, including corrosion resistance, wear resistance and fatigue life. In this dissertation, the influence of machining conditions, including dry and cryogenic cooling (liquid nitrogen was sprayed to the machined surface during machining), cutting edge radius, cutting speed and feed rate, on the surface integrity of AZ31B Mg alloy was investigated. Cryogenic machining led to the formation of a "featureless layer" on the machined surface where significant grain refinement from 12 microm to 31 nm occurred due to dynamic recrystallization (DRX), as well as increased intensity of basal plane on the surface and more compressive residual stresses. Dry and cryogenic burnishing experiments of the same material were conducted using a fixed roller setup. The thickness of the processed-influenced layer, where remarkable microstructural changes occurred, was dramatically increased from the maximum value of 20 microm during machining to 3.4 mm during burnishing. The burnishing process also produced a stronger basal texture on the surface than the machining process. Preliminary corrosion tests were conducted to evaluate the corrosion performance of selected machined and burnished AZ31B Mg samples in 5% NaCl solution and simulated body fluid (SBF ). Cryogenic cooling and large edge radius tools were found to significantly improve the corrosion performance of machined samples in both solutions. The largest improvement in the material's corrosion performance was achieved by burnishing. A finite element study was conducted for machining of AZ31B Mg alloy and calibrated using the experimental data. A user subroutine was developed and incorporated to predict the grain size changes induced by machining. Good agreements between the predicted and measured grain size as well as thickness of featureless layers were achieved. Numerical studies were extended to include the influence of rake angle, feed rate and cutting speed on the featureless layer formation. KEYWORDS: Surface Integrity, Cryogenic Machining/Burnishing, Corrosion Resistance, Finite Element Analysis, Magnesium Alloys.

Pu, Zhengwen

495

Dissolution of Eutectic ?-Mg17Al12 Phase in Magnesium AZ91 Cast Alloy at Temperatures Close to Eutectic Temperature  

NASA Astrophysics Data System (ADS)

Knowledge on the dissolution kinetics of ?-eut phase in cast Mg AZ91 alloy at temperatures close to the eutectic temperature is very useful for various processes of the alloy. In the present study, dissolution of ?-eut phase has been investigated experimentally and considered theoretically. Results have confirmed that the kinetics of ?-eut dissolution is basically diffusion controlled. Optimum times for dissolution heat treatment practice of different sizes of cast microstructure which are cooling rate dependant during casting could be suggested based on the present calculation. For fusion welding of the alloy, the present results indicate the difficulty of having a heating rate lower than the critical value (“critical heating rate”) for a significant reduction of the phase to avoid constitutional liquation.

Zhu, Tianping; Chen, Zhan W.; Gao, Wei

2010-08-01

496

Star and Dust Formation Activities in AzTEC-3: A Starburst Galaxy at z=5.3  

NASA Technical Reports Server (NTRS)

Analyses of 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. In this lecture we add this constraint to the analysis of AzTEC-3, a starburst galaxy at z=5.3. 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. 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.

Dwek, Eliahu

2011-01-01

497

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

SciTech Connect

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 system 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.

Riechers, Dominik A.; Scoville, Nicholas Z. [Astronomy Department, California Institute of Technology, MC 249-17, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Capak, Peter L.; Yan, Lin [Spitzer Science Center, California Institute of Technology, MC 220-6, 1200 East California Boulevard, Pasadena, CA 91125 (United States); Carilli, Christopher L. [National Radio Astronomy Observatory, P.O. Box O, Socorro, NM 87801 (United States); Cox, Pierre; Neri, Roberto [Institut de RadioAstronomie Millimetrique, 300 Rue de la Piscine, Domaine Universitaire, 38406 Saint Martin d'Heres (France); Schinnerer, Eva [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Bertoldi, Frank, E-mail: dr@caltech.ed [Argelander-Institut fuer Astronomie, Universitaet Bonn, Auf dem Huegel 71, Bonn, D-53121 (Germany)

2010-09-10

498

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

SciTech Connect

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 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.

Dwek, Eli; Staguhn, Johannes G.; Arendt, Richard G.; Benford, Dominic J.; Fixsen, Dale; Maher, Stephen F.; Moseley, Samuel H.; Sharp, Elmer H. [Observational Cosmology Lab, Code 665, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Capak, Peter L. [Spitzer Science Centre, 314-6 California Institute of Technology, 1200 E. California Blvd., Pasadena, CA 91125 (United States); Kovacs, Attila [University of Minnesota, 116 Church St SE, Minneapolis, MN 55414 (United States); Karim, Alexander; Schinnerer, Eva [Max-Planck-Institute fuer Astronomie, Koenigstuhl 17, D-69117, Heidelberg (Germany); Leclercq, Samuel [Institut de RadioAstronomie Millimetrique, 300 rue de la Piscine, 38406 Saint Martin d'Heres (France)

2011-09-01

499

Anaglyph, Salt Lake City, Utah  

NASA Technical Reports Server (NTRS)

The 2002 Winter Olympics are hosted by Salt Lake City at several venues within the city, in nearby cities, and within the adjacent Wasatch Mountains. This anaglyph image provides a stereoscopic map view of north central Utah that includes all of these Olympic sites. In the south, next to Utah Lake, Provo hosts the ice hockey competition. In the north, northeast of the Great Salt Lake, Ogden hosts curling and the nearby Snowbasin ski area hosts the downhill events. In between, southeast of the Great Salt Lake, Salt Lake City hosts the Olympic Village and the various skating events. Further east, across the Wasatch Mountains, the Park City ski resort hosts the bobsled, ski jumping, and snowboarding events. The Winter Olympics are always hosted in mountainous terrain. This view shows the dramatic landscape that makes the Salt Lake City region a world-class center for winter sports.

The stereoscopic effect of this anaglyph was created by first draping a Landsat satellite image over a Shuttle Radar Topography Mission digital elevation model and then generating two differing perspectives, one for each eye. When viewed through special glasses, the result is a vertically exaggerated view of Earth's surface in its full three dimensions. Anaglyph glasses cover the left eye with a red filter and cover the right eye with a blue filter.

Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and will substantially help in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).

Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter(approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C.

Size: 222 x 93.8 kilometers (138 x 58.2 miles) Location: 40.0 to 42.0 deg. North lat., 111.25 to 112.25.0 deg. West lon.(exactly) Orientation: North at top Image Data: Landsat Bands 3, 2, 1 as panchromatic grey. Original Data Resolution: SRTM 1 arcsecond (30 meters or 98 feet), Thematic Mapper 30 meters (98 feet) Date Acquired: February 2000 (SRTM), 1990s (Landsat 5 image mosaic)

2002-01-01

500

Cities/Buildings Image Archive  

NSDL National Science Digital Library

Created as a resource for educators and architectural professionals by Meredith L. Clausen, Professor of Architectural History at University of Washington, this site contains a well-organized, straightforward image archive of buildings and architectural features from around the world. The archive is organized by country, city/town, and building/site. While the archive is not exceptionally large, users will find photos of a wide variety of private and public buildings in a myriad of architectural styles, such as train stations, hotels, government buildings, markets, typical houses, and churches.