Spatial refugia mediate juvenile coral survival during coral-predator interactions

NASA Astrophysics Data System (ADS)

Gallagher, Clare; Doropoulos, Christopher

2017-03-01

Coral recruitment and juvenile growth are essential processes for coral population maintenance and recovery. A growing body of research has evaluated the influence of reef microstructure on coral settlement and post-settlement survival, showing that physical refugia enhance recruitment. These studies have evaluated coral recruit morality from competition with macroalgae and indirect predation by grazing organisms, but the impact of direct predation by corallivorous piscine species on juvenile corals and how this interacts with reef microstructure is relatively unknown. This study examined whether refugia provided by micro-crevices enhance juvenile coral survival from corallivory. Juvenile corals from two different functional groups, the slow-growing massive Porites lobata and fast-growing branching Pocillopora damicornis, with average nubbin sizes of 1.4 cm × 0.3 cm and 0.5 cm × 1.0 cm (diameter × height), respectively, were attached to experimental tiles using small (1.44 cm3) and large (8.0 cm3) crevice sizes and were monitored for 29 d on a forereef in Palau. Full crevices (four sided) enhanced coral survival compared to exposed microhabitats in both coral taxa, but crevice size did not alter survival rates. Corallivores targeted recruits within crevices regardless of crevice size; dominant predators included small triggerfish (Balistidae), butterflyfish ( Chaetodon), and wrasse ( Cheilinus). Overall, Pocillopora suffered much higher rates of mortality than Porites. All Pocillopora were consumed by day 8 of the experiment, but mortality was significantly delayed in full crevices compared to exposed and partial crevice (three sided) microhabitats. In contrast, Por. lobata located in all microhabitats survived the entire experiment up to 29 d, with high survival in full (>90%) and partial crevices (70%), but only 28% survival in exposed microhabitats. These findings show the importance of crevices as spatial refugia from predators for juvenile corals and highlight the importance of structural complexity for juvenile coral growth and survival that enhances reef recovery.

Self-organization of intertidal snails facilitates evolution of aggregation behavior.

PubMed

Stafford, Richard; Davies, Mark S; Williams, Gray A

2008-01-01

Many intertidal snails form aggregations during emersion to minimize desiccation stress. Here we investigate possible mechanisms for the evolution of such behavior. Two behavioral traits (following of mucus trails, and crevice occupation), which both provide selective advantages to individuals that possess the traits over individuals that do not, result in self-organization of aggregations in crevices in the rock surface. We suggest that the existence of self-organizing aggregations provides a mechanism by which aggregation behavior can evolve. The inclusion of an explicitly coded third behavior, aggregation, in a simulated population produces patterns statistically similar to those found on real rocky shores. Allowing these three behaviors to evolve using an evolutionary algorithm, however, results in aggregation behavior being selected against on shores with high crevice density. The inclusion of broadcast spawning dispersal mechanisms in the simulation, however, results in aggregation behavior evolving as predicted on shores with both high crevice density and low crevice density (evolving in crevices first, and then both in crevices and on flat rock), indicating the importance of environmental interactions in understanding evolutionary processes. We propose that self-organization can be an important factor in the evolution of group behaviors.

Roosting ecology of the pallid bat, Antrozous pallidus

USGS Publications Warehouse

Vaughan, Terry A.; O'Shea, Thomas J.

1976-01-01

Daytime roosting behavior of pallid bats (Antrozous pallidus) was studied in central Arizona. Bats were present in the area from March or April until November and roosted in cliffs in colonies generally including 20 or more individuals. Pallid bats were highly selective in their choice of roost sites and minimized diurnal energy output by adaptive hypothermia and behavioral thermo-regulation. In spring and autumn the bats roosted in vertical crevices responsive to changes in ambient temperatures. Here temperatures remained low and the bats were torpid for much of the day, but when the crevices became heated in the late afternoon the bats were passively warmed prior to emergence. Deep, horizontal crevices were preferred in summer; cliffs function as massive heat sinks, and in summer crevice temperatures remained moderate and relatively stable. Throughout most of the day both the deep parts of the crevices and the body temperatures of the bats remained close to 30ºC; at this body temperature pallid bats have unexpectedly low metabolic rates (Trune, 1974). By adjusting their positions and closeness to other bats in the thermal gradient within the crevice, bats dissipate heat early in the day, maintain a low metabolic rate through most of the fat and elevate the body temperature prior to emergence in the evening. Of vital important to pallid bats in the summer are social behaviors that promote communal roosting at "traditional" crevices.

Niche partitioning of feeding microhabitats produces a unique function for herbivorous rabbitfishes (Perciformes, Siganidae) on coral reefs

NASA Astrophysics Data System (ADS)

Fox, R. J.; Bellwood, D. R.

2013-03-01

Niche theory predicts that coexisting species minimise competition by evolving morphological or behavioural specialisations that allow them to spread out along resource axes such as space, diet and temporal activity. These specialisations define how a species interacts with its environment and, by extension, determine its functional role. Here, we examine the feeding niche of three species of coral reef-dwelling rabbitfishes (Siganidae, Siganus). By comparing aspects of their feeding behaviour (bite location, bite rate, foraging distance) with that of representative species from two other abundant herbivorous fish families, the parrotfishes (Labridae, Scarus) and surgeonfishes (Acanthuridae, Acanthurus), we examine whether rabbitfishes have a feeding niche distinct from other members of the herbivore guild. Measurements of the penetration of the fishes' snouts and bodies into reef concavities when feeding revealed that rabbitfish fed to a greater degree from reef crevices and interstices than other herbivores. There was just a 40 % overlap in the penetration-depth niche between rabbitfish and surgeonfish and a 45 % overlap between rabbitfish and parrotfish, compared with the almost complete niche overlap (95 %) recorded for parrotfish and surgeonfish along this spatial niche axis. Aspects of the morphology of rabbitfish which may contribute to this niche segregation include a comparatively longer, narrower snout and narrower head. Our results suggest that sympatric coexistence of rabbitfish and other reef herbivores is facilitated by segregation along a spatial (and potentially dietary) axis. This segregation results in a unique functional role for rabbitfishes among roving herbivores that of "crevice-browser": a group that specifically feeds on crevice-dwelling algal or benthic organisms. This functional trait may have implications for reef ecosystem processes in terms of controlling the successional development of crevice-based algal communities, reducing their potential to trigger macroalgal outbreaks.

Measurements and mechanisms of localized aqueous corrosion in aluminum-lithium alloys

NASA Technical Reports Server (NTRS)

Buchheit, Rudolph G., Jr.; Stoner, Glenn E.

1990-01-01

Like most heat treatable aluminum alloys, localized corrosion and stress corrosion of Al-Li-Cu alloys is strongly dependent on the nature and distribution of second phase particles. To develop a mechanistic understanding of the role of localized corrosion in the stress corrosion process, bulk samples of T(sub 1) (Al2CuLi) and a range of Al-Cu-Fe impurity phases were prepared for electrochemical experiments. Potentiodynamic polarization and galvanic couple experiments were performed in standard 0.6 M NaCl and in simulated crevice solutions to assess corrosion behavior of these particles with respect to the alpha-Al matrix. A comparison of time to failure versus applied potential using a constant load, smooth bar SCC test technique in Cl(-), Cl(-)/CrO4(2-), and Cl(-)/CO3(2-) environments shows that rapid failures are to be expected when applied potentials are more positive than the breakaway potential (E sub br) of T(sub 1) (crack tip) but less than E(sub br) of alpha-Al (crack walls). It is shown that this criterion is not satisfied in aerated Cl(-) solutions. Accordingly, SCC resistance is good. This criterion is satisfied, however, in an alkaline isolated fissure exposed to a CO2 containing atmosphere. Rapid failure induced by these fissures was recently termed preexposure embrittlement. Anodic polarization shows that the corrosion behavior of T(sub 1) is relatively unaffected in alkaline CO3(2-) environments but the alpha-Al phase is rapidly passivated. X ray diffraction of crevice walls from artificial crevices suggests that passivation of alpha-Al occurs as hydrotalcite-type compound (LiAl2(OH)6)2(+) - CO3(2-) - nH2O.

Determination of the Corrosive Conditions Present within Aircraft Lap-Splice Joints

NASA Technical Reports Server (NTRS)

Lewis, Karen S.; Kelly, Robert G.; Piascik, Robert S.

1999-01-01

The complexity of airframe structure lends itself to damage resulting from crevice corrosion. Fuselage lap-splice joints are a particularly important structural detail in this regard because of the difficulty associated with detection and measurement of corrosion in these occluded regions. The objective of this work is to develop a laboratory corrosion test protocol to identify the chemistry to which lap joints are exposed and to develop a model of the corrosion within the joints. A protocol for collecting and identifying the chemistry of airframe crevice corrosion has been developed. Capillary electrophoresis (CE) is used to identify the ionic species contained in corrosion product samples removed from fuselage lap splice joints. CE analysis has been performed on over sixty corrosion product samples removed from both civilian and military aircraft. Over twenty different ions have been detected. Measurements of pH of wetted corroded surfaces indicated an alkaline occluded solution. After determining the species present and their relative concentrations, the resultant solution was reproduced in bulk and electrochemical tests were performed to determine the corrosion rate. Electrochemical analyses of the behavior of AA2024-T3 in these solutions gave corrosion rates of up to 250 microns per year (10 mpy). Additional tests have determined the relative importance of each of the detected ions in model solutions used for future predictive tests. The statistically significant ions have been used to create a second generation solution. Laboratory studies have also included exposure tests involving artificial lap joints exposed to various simulated bulk and crevice environments. The extent and morphology of the attack in artificial lap joints has been compared to studies of corroded samples from actual aircraft. Other effects, such as temperature and potential, as well as the impact of the environment on fatigue crack growth have also been studied.

Western crevice and cavity-roosting bats

USGS Publications Warehouse

Bogan, Michael A.; Cryan, Paul M.; Valdez, Ernest W.; Ellison, Laura E.; O'Shea, Thomas J.

2003-01-01

Among the 45 species of bats that occur in the United States (U.S.), 34 species regularly occur in western regions of the country. Many of these “western” species choose roost sites in crevices or cavities. Herein we provide an introduction to the biology of bats that roost in cavities and crevices and assess the challenges and opportunities associated with monitoring their populations. We reviewed recent studies and examined the U.S. Geological Survey Bat Population Database (BPD) for records of western bats using crevice and cavity roosts. We found records of 25 species of western bats that use crevice or cavity roosts for at least part of their annual cycle. There were relatively few (n = 92) observations or counts for these species in the BPD, representing only 6% of the observations in the database. This paucity of records likely reflects the difficulty of observing bats in such situations rather than actual use. We found no long-term data adequate for population trend analysis among this group of bats. Since the development of miniaturized radio transmitters, our knowledge about bats that roost in cavities and crevices has increased. Future challenges associated with monitoring these species will include understanding variability in the types of roosts used as well as the roost-switching behavior exhibited by many species.

CFD simulations of Rapid Compression Machines using detailed chemistry: Evaluation of the ‘crevice containment’ concept

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

Bourgeois, Nicolas; Goldsborough, S. Scott; Jeanmart, Herve

The use of creviced pistons in Rapid Compression Machines (RCMs) has proven to be very effcient in making the temperature homogeneous inside the reaction chamber but has the disadvantage of inducing a mass transfer from the reaction chamber to the crevice, especially during the preliminary heat release of two- stage ignition processes. Aiming to mitigate this mass transfer, the technique of `crevice containment' (CC) has been proposed. It consists of a physical separa- tion between the reaction chamber and the crevice region that is engaged at the end of the compression, physically preventing any mass transfer between both parts ofmore » the geometry. In order to numerically assess this novel design concept across a broader range of conditions than previously investigated, reactive simu- lations using detailed chemical kinetic mechanisms are performed for n-heptane and iso-octane. For compressed temperatures outside of the NTC (negative temperature coeffcient) region, the CC approach is very effective in suppress- ing the influence of the crevice mass transfer and thus increases the validity of the widely-used 0-D model based on the adiabatic core assumption. Still, for most of the temperature cases inside the NTC region, the ignition appears to be precipitately initiated in the residual vortex region formed after the seal engagement, possibly inducing very significant differences with the 0-D model. The benefits of eliminating the post-compression crevice mass transfer appear to be counter-balanced by effects that have not been previously investigated in detail.« less

CFD simulations of Rapid Compression Machines using detailed chemistry: Evaluation of the ‘crevice containment’ concept

DOE PAGES

Bourgeois, Nicolas; Goldsborough, S. Scott; Jeanmart, Herve; ...

2018-01-17

The use of creviced pistons in Rapid Compression Machines (RCMs) has proven to be very effcient in making the temperature homogeneous inside the reaction chamber but has the disadvantage of inducing a mass transfer from the reaction chamber to the crevice, especially during the preliminary heat release of two- stage ignition processes. Aiming to mitigate this mass transfer, the technique of `crevice containment' (CC) has been proposed. It consists of a physical separa- tion between the reaction chamber and the crevice region that is engaged at the end of the compression, physically preventing any mass transfer between both parts ofmore » the geometry. In order to numerically assess this novel design concept across a broader range of conditions than previously investigated, reactive simu- lations using detailed chemical kinetic mechanisms are performed for n-heptane and iso-octane. For compressed temperatures outside of the NTC (negative temperature coeffcient) region, the CC approach is very effective in suppress- ing the influence of the crevice mass transfer and thus increases the validity of the widely-used 0-D model based on the adiabatic core assumption. Still, for most of the temperature cases inside the NTC region, the ignition appears to be precipitately initiated in the residual vortex region formed after the seal engagement, possibly inducing very significant differences with the 0-D model. The benefits of eliminating the post-compression crevice mass transfer appear to be counter-balanced by effects that have not been previously investigated in detail.« less

Boulder Clusters as Flow Refugia for Juvenile Salmonids and Aquatic Invertebrates in Steep Mountain Streams, Klamath Mountains, Northern California

NASA Astrophysics Data System (ADS)

Cover, M. R.; May, C. L.; Dietrich, W. E.; Resh, V. H.

2005-12-01

The availability of flow refugia and cover is an important factor affecting habitat suitability for fish and invertebrates, especially in steep, turbulent streams. In some channels, crevices beneath and between large rocks may be the only available flow refugia that allow rainbow trout (Oncorhynchus mykiss) to conserve energy and escape from high velocity flow during large storm events. Many aquatic invertebrates, especially large or crawling taxa, require cover that is provided by unembedded crevice space underneath large stones. To investigate the influence of channel type on habitat availability, we performed intensive surveys of crevice habitat for salmonids and benthic invertebrates in 12 reaches in Walker Creek, a 25 square km basin in the Klamath Mountains of Northern California. We identified four reaches in each of three channel types: plane bed (3.1% - 3.7% slope), step-pool (5.4% - 6.5% slope), and cascade (6.3% - 8.5% slope). We used 4 realistic fish models (5, 10, 15, and 20 cm length) to assess the size of crevices and presence of flow refugia associated with all cobble (64 - 256 mm) and boulder (> 256 mm) grains within five 0.5 m-wide diagonal transects. The total abundance of crevices was similar among plane bed (6.3 +/- 1.1 m-2) (Mean +/- SD), step-pool (6.2 +/- 0.25 m-2), and cascade (6.7 +/- 1.2 m-2) reaches. Small (5 cm) crevices made up the majority of crevices in all three reach types. While the presence of 5 cm and 10 cm crevices was not significantly different between the three channel types, there were significantly more large (20 cm) crevices in cascade (0.73 +/- 0.33 m-2) and step-pool (0.68 +/- 0.1 m-2) reaches than in plane bed (0.26 +/- 0.14 m-2) reaches (AVOVA, p < 0.05). Moderately sized (15 cm) crevices were more common in step-pool reaches (0.91 +/- 0.13 m-2) than either cascade (0.54 +/- 0.15 m-2) or plane bed (0.42 +/- 0.13 m-2) reaches. Based on these results we conclude that step-pool reaches provide the most favorable habitat for larger (15 to 20 cm) fish, probably due to the channel-spawning clusters of large cobbles and boulders that define this channel type. Understanding the processes that develop and maintain these open-framework clusters is important for basin-scale assessment of potential aquatic habitat.

Reliability evaluation of oil pipelines operating in aggressive environment

NASA Astrophysics Data System (ADS)

Magomedov, R. M.; Paizulaev, M. M.; Gebel, E. S.

2017-08-01

In connection with modern increased requirements for ecology and safety, the development of diagnostic services complex is obligatory and necessary enabling to ensure the reliable operation of the gas transportation infrastructure. Estimation of oil pipelines technical condition should be carried out not only to establish the current values of the equipment technological parameters in operation, but also to predict the dynamics of changes in the physical and mechanical characteristics of the material, the appearance of defects, etc. to ensure reliable and safe operation. In the paper, existing Russian and foreign methods for evaluation of the oil pipelines reliability are considered, taking into account one of the main factors leading to the appearance of crevice in the pipeline material, i.e. change the shape of its cross-section, - corrosion. Without compromising the generality of the reasoning, the assumption of uniform corrosion wear for the initial rectangular cross section has been made. As a result a formula for calculation the probability of failure-free operation was formulated. The proposed mathematical model makes it possible to predict emergency situations, as well as to determine optimal operating conditions for oil pipelines.

Grand Marais Harbor, Cook County, Minnesota, Operation and Maintenance Activities, Environment Assessment Report.

DTIC Science & Technology

1974-12-01

34 - . .. .. . . . . . . -.. 2.523 In rocky crevices along the shore walls there are a variety of sedges, rushes, grasses, mosses, lichens ...our dre~tinn anid d!’aonal planu ~ for 1rand ’N r~ls Hxariors ihe a1tcrrat.v.e deacrit’,ed In’ tti..i; le.tter ealicatn. dipoa plans for l𔃺tii pollato-4

Feeding behaviour: hydrothermal vent crabs feast on sea 'snow'.

PubMed

Jeng, M-S; Ng, N K; Ng, P K L

2004-12-23

The crab Xenograpsus testudinatus lives at enormously high densities around the sulphur-rich hydrothermal vents found in shallow waters off Taiwan, even though this acidic environment is low in nutrients. Here we show that these crabs swarm out of their crevices at slack water and feed on the vast numbers of zooplankton that are killed by the vents' sulphurous plumes, and that rain down like marine 'snow'. This opportunistic feeding behaviour explains how the crabs are able to survive in the adverse toxic environment of these shallow hydrothermal vents.

Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

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

Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D.

1988-04-01

Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion;more » sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.« less

Modeling local chemistry in PWR steam generator crevices

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

Millett, P.J.

1997-02-01

Over the past two decades steam generator corrosion damage has been a major cost impact to PWR owners. Crevices and occluded regions create thermal-hydraulic conditions where aggressive impurities can become highly concentrated, promoting localized corrosion of the tubing and support structure materials. The type of corrosion varies depending on the local conditions, with stress corrosion cracking being the phenomenon of most current concern. A major goal of the EPRI research in this area has been to develop models of the concentration process and resulting crevice chemistry conditions. These models may then be used to predict crevice chemistry based on knowledgemore » of bulk chemistry, thereby allowing the operator to control corrosion damage. Rigorous deterministic models have not yet been developed; however, empirical approaches have shown promise and are reflected in current versions of the industry-developed secondary water chemistry guidelines.« less

Gimme shelter: The importance of crevices to some fish species inhabiting a deeper-water rocky outcrop in Southern California

USGS Publications Warehouse

Love, M.S.; Schroeder, D.M.; Lenarz, B.; Cochrane, G.R.

2006-01-01

Federal law governing fisheries management recognizes the role habitat plays in structuring fish assemblages and achieving sustainable fisheries. However, in most instances it is not known which aspects of habitat are important to the lives of fish species. In 2004, we examined the importance of sheltering sites (crevices) to fishes living along low ledges in deeper waters off Anacapa Island, southern California. We found that patterns of fish-habitat relationships varied among the eight most abundant species. Three species, bocaccio (Sebastes paucispinis), vermilion (S. miniatus), and flag (S. rubrivinctus) rockfishes, had densities one to three orders of magnitude greater in the deep crevice habitat compared to low relief rock or shallow crevice habitats. Density and mean size of the two most abundant fishes, halfbanded (S. semicinctus) and squarespot (S. hopkinsi) rockfishes, generally increased as complexity of rock habitat increased. Not all species had the highest densities in deep crevice habitat. Greenspotted rockfish (S. chlorostictus) and blackeye goby (Rhinogobiops nicholsii) showed no significant difference in density among rock habitats. Pink seaperch (Zalembius rosaceus) were absent in the deep crevice habitat and abundant only in low relief rock habitats. Our study implies that it is not sufficient to distinguish only between soft and hard bottom types when using habitat to guide fisheries management strategies. Finer-scale investigations of fish-habitat relationships, paired with habitat mapping and groundtruthing, aid in the design and positioning of Marine Park Areas (MPAs) and are necessary to facilitate understanding of how a particular MPA may contribute to fisheries management.

Autumn migration and selection of rock crevices as hibernacula by big brown bats in Colorado

USGS Publications Warehouse

Neubaum, D.J.; O'Shea, T.J.; Wilson, K.R.

2006-01-01

Movements, distribution, and roosting requirements of most species of temperate-zone bats in autumn are poorly understood. We conducted the 1st radiotelemetry study of autumn migrations and prehibernation roost selection of bats in western North America. Big brown bats (Eptesicus fuscus, n = 55) in the Poudre River watershed, Colorado, moved from low-elevation summer ranges to high-elevation locations in autumn, where they roosted in rock crevices during the period leading up to winter hibernation. We characterized rock crevices used as roosts in autumn at these higher elevations at microhabitat and landscape scales. We used logistic regression combined with an information theoretic approach to determine which variables were most important in roost selection. At the microhabitat scale, autumn roosts were higher to the ground above and below the exit point and were in deeper crevices that had more constant temperatures than randomly selected crevices. At the landscape scale, aspect of the hillside was important, with autumn roosts typically facing north-northwest. Autumn roosts fell into 2 categories: those used for a few days (transient roosts) and those used for ≥7 days and presumed to be hibernacula. Temperature regimes in the presumed hibernacula appear to provide optimal conditions for use of winter torpor, whereas transient roosts may offer passive rewarming and energy savings for bats still active in early autumn. Elevational segregation of sexes also was documented in our region, with a preponderance of females found at lower elevations and males at higher elevations in summer. Sex ratios at higher elevations became even in autumn. Use of short elevational migrations and selection of hibernation sites in rock crevices may be a common overwintering strategy of insectivorous bats of western North America.

Visualization and Analysis of Biomaterial-Centered Thrombus Formation within a Defined Crevice Under Flow

PubMed Central

Jamiolkowski, Megan A.; Pedersen, Drake D.; Wu, Wei-Tao; Antaki, James F.; Wagner, William R.

2016-01-01

The blood flow pathway within a device, together with the biomaterial surfaces and status of the patient’s blood, are well-recognized factors in the development of thrombotic deposition and subsequent embolization. Blood flow patterns are of particular concern for devices such as blood pumps (i.e. ventricular assist devices, VADs) where shearing forces can be high, volumes are relatively large, and the flow fields can be complex. However, few studies have examined the effect of geometric irregularities on thrombus formation on clinically relevant opaque materials under flow. The objective of this study was to quantify human platelet deposition onto Ti6Al4V alloys, as well as positive and negative control surfaces, in the region of defined crevices (~50–150 µm in width) that might be encountered in many VADs or other cardiovascular devices. To achieve this, reconstituted fresh human blood with hemoglobin-depleted red blood cells (to achieve optical clarity while maintaining relevant rheology), long working optics, and a custom designed parallel plate flow chamber were employed. The results showed that the least amount of platelet deposition occurred in the largest crevice size examined, which was counterintuitive. The greatest levels of deposition occurred in the 90 µm and 53 µm crevices at the lower wall shear rate. The results suggest that while crevices may be unavoidable in device manufacturing, the crevice size might be tailored, depending on the flow conditions, to reduce the risk of thromboembolic events. Further, these data might be used to improve the accuracy of predictive models of thrombotic deposition in cardiovascular devices to help optimize the blood flow path and reduce device thrombogenicity. PMID:27156141

Clonality of bacterial consortia in root canals and subjacent gingival crevices.

PubMed

Parahitiyawa, Nipuna B; Chu, Frederick C S; Leung, Wai K; Yam, Wing C; Jin, Li Jian; Samaranayake, Lakshman P

2015-02-01

No oral niche can be considered to be segregated from the subjacent milieu because of the complex community behavior and nature of the oral biofilms. The aim of this study was to address the paucity of information on how these species are clonally related to the subjacent gingival crevice bacteria. We utilized a metagenomic approach of amplifying 16S rDNA from genomic DNA, cloning, sequencing and analysis using LIBSHUFF software to assess the genetic homogeneity of the bacterial species from two infected root canals and subjacent gingival crevices. The four niches studied yielded 186 clones representing 54 phylotypes. Clone library comparisons using LIBSHUFF software indicated that each niche was inhabited by a unique flora. Further, 42% of the clones were of hitherto unknown phylotypes indicating the extent of bacterial diversity, especially in infected root canals and subjacent gingival crevices. We believe data generated through this novel analytical tool shed new light on understanding oral microbial ecosystems. © 2014 Wiley Publishing Asia Pty Ltd.

Chlorpyrifos accumulation patterns for child-accessible surfaces and objects and urinary metabolite excretion by children for 2 weeks after crack-and-crevice application.

PubMed

Hore, Paromita; Robson, Mark; Freeman, Natalie; Zhang, Jim; Wartenberg, Daniel; Ozkaynak, Halûk; Tulve, Nicolle; Sheldon, Linda; Needham, Larry; Barr, Dana; Lioy, Paul J

2005-02-01

The Children's Post-Pesticide Application Exposure Study (CPPAES) was conducted to look at the distribution of chlorpyrifos within a home environment for 2 weeks after a routine professional crack-and-crevice application and to determine the amount of the chlorpyrifos that is absorbed by a child living within the home. Ten residential homes with a 2- to 5-year-old child in each were selected for study, and the homes were treated with chlorpyrifos. Pesticide measurements were made from the indoor air, indoor surfaces, and plush toys. In addition, periodic morning urine samples were collected from each of the children throughout the 2-week period. We analyzed the urine samples for 3,5,6-trichloropyridinol, the primary urinary metabolite of chlorpyrifos, and used the results to estimate the children's absorbed dose. Average chlorpyrifos levels in the indoor air and surfaces were 26 (pretreatment)/120 (posttreatment) ng/m3 and 0.48 (pretreatment)/2.8 (posttreatment) ng/cm2, respectively, reaching peak levels between days 0 and 2; subsequently, concentrations decreased throughout the 2-week period. Chlorpyrifos in/on the plush toys ranged from 7.3 to 1,949 ng/toy postapplication, with concentrations increasing throughout the 2-week period, demonstrating a cumulative adsorption/absorption process indoors. The daily amount of chlorpyrifos estimated to be absorbed by the CPPAES children postapplication ranged from 0.04 to 4.8 microg/kg/day. During the 2 weeks after the crack-and-crevice application, there was no significant increase in the amount of chlorpyrifos absorbed by the CPPAES children.

Results from Alloy 600 And Alloy 690 Caustic SCC Model Boiler Tests

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

Miller, Frederick D.; Thomas, Larry E.

2009-08-03

A versatile model boiler test methodology was developed and used to compare caustic stress corrosion cracking (SCC) of mill annealed Alloy 600 and thermally treated Alloy 690. The model boiler included simulated crevice devices that efficiently and consistently concentrated Na2CO3, resulting in volatilization of CO2 with the steam and concentration of NaOH at the tube surfaces. The test methodology also included variation in tube stress, either produced by the primary to secondary side pressure differential, or by a novel method that reproducibly yields a higher stress condition on the tube. The significant effect of residual stress on tube SCC wasmore » also considered. SCC of both Alloy 600 and Alloy 690 were evaluated as a function of temperature and stress. Analytical transmission electron microscopy (ATEM) evaluations of the cracks and the grain boundaries ahead of the cracks were performed, providing insight into the SCC mechanism. This model boiler test methodology may be applicable to a range of bulkwater secondary chemistries that concentrate to produce aggressive crevice environments.« less

Crevice corrosion - NaCl concentration map for grade-2 titanium at elevated temperature

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

Tsujikawa, Shigeo; Kojima, Yoichi

1993-12-31

The repassivation potential, ER, for metal/metal-crevice of Commercially Pure Titanium, C.P.Ti, was determined in NaCl solutions at temperatures up to 250C. The ER has its least noble value near 100C and becomes more noble as the temperature increases. As shown in previous research, the shrinkage of the repassivation region should continue with increasing temperatures. However, in conducting this same experiment at temperatures higher than 100C, an examination of the NaCl concentration - temperature - crevice corrosion map verifies that the repassivation region began to expand again when the temperature exceeded 140C. This expansion continued as the temperature continued to increase.

The role of trapped bubbles in kidney stone detection with the color Doppler ultrasound twinkling artifact.

PubMed

Simon, Julianna C; Sapozhnikov, Oleg A; Kreider, Wayne; Breshock, Michael; Williams, James C; Bailey, Michael R

2018-01-09

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging bubbles, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice bubble hypothesis of twinkling and suggest the kidney stone crevices that give rise to the twinkling phenomenon may be internal as well as external.

The role of trapped bubbles in kidney stone detection with the color Doppler ultrasound twinkling artifact

NASA Astrophysics Data System (ADS)

Simon, Julianna C.; Sapozhnikov, Oleg A.; Kreider, Wayne; Breshock, Michael; Williams, James C., Jr.; Bailey, Michael R.

2018-01-01

The color Doppler ultrasound twinkling artifact, which highlights kidney stones with rapidly changing color, has the potential to improve stone detection; however, its inconsistent appearance has limited its clinical utility. Recently, it was proposed stable crevice bubbles on the kidney stone surface cause twinkling; however, the hypothesis is not fully accepted because the bubbles have not been directly observed. In this paper, the micron or submicron-sized bubbles predicted by the crevice bubble hypothesis are enlarged in kidney stones of five primary compositions by exposure to acoustic rarefaction pulses or hypobaric static pressures in order to simultaneously capture their appearance by high-speed photography and ultrasound imaging. On filming stones that twinkle, consecutive rarefaction pulses from a lithotripter caused some bubbles to reproducibly grow from specific locations on the stone surface, suggesting the presence of pre-existing crevice bubbles. Hyperbaric and hypobaric static pressures were found to modify the twinkling artifact; however, the simple expectation that hyperbaric exposures reduce and hypobaric pressures increase twinkling by shrinking and enlarging bubbles, respectively, largely held for rough-surfaced stones but was inadequate for smoother stones. Twinkling was found to increase or decrease in response to elevated static pressure on smooth stones, perhaps because of the compression of internal voids. These results support the crevice bubble hypothesis of twinkling and suggest the kidney stone crevices that give rise to the twinkling phenomenon may be internal as well as external.

Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

PubMed

Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

2017-11-11

Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

Chlorpyrifos Accumulation Patterns for Child-Accessible Surfaces and Objects and Urinary Metabolite Excretion by Children for 2 Weeks after Crack-and-Crevice Application

PubMed Central

Hore, Paromita; Robson, Mark; Freeman, Natalie; Zhang, Jim; Wartenberg, Daniel; Özkaynak, Halûk; Tulve, Nicolle; Sheldon, Linda; Needham, Larry; Barr, Dana; Lioy, Paul J.

2005-01-01

The Children’s Post-Pesticide Application Exposure Study (CPPAES) was conducted to look at the distribution of chlorpyrifos within a home environment for 2 weeks after a routine professional crack-and-crevice application and to determine the amount of the chlorpyrifos that is absorbed by a child living within the home. Ten residential homes with a 2- to 5-year-old child in each were selected for study, and the homes were treated with chlorpyrifos. Pesticide measurements were made from the indoor air, indoor surfaces, and plush toys. In addition, periodic morning urine samples were collected from each of the children throughout the 2-week period. We analyzed the urine samples for 3,5,6-trichloropyridinol, the primary urinary metabolite of chlorpyrifos, and used the results to estimate the children’s absorbed dose. Average chlorpyrifos levels in the indoor air and surfaces were 26 (pretreatment)/120 (posttreatment) ng/m3 and 0.48 (pretreatment)/2.8 (posttreatment) ng/cm2, respectively, reaching peak levels between days 0 and 2; subsequently, concentrations decreased throughout the 2-week period. Chlorpyrifos in/on the plush toys ranged from 7.3 to 1,949 ng/toy postapplication, with concentrations increasing throughout the 2-week period, demonstrating a cumulative adsorption/absorption process indoors. The daily amount of chlorpyrifos estimated to be absorbed by the CPPAES children postapplication ranged from 0.04 to 4.8 μg/kg/day. During the 2 weeks after the crack-and-crevice application, there was no significant increase in the amount of chlorpyrifos absorbed by the CPPAES children. PMID:15687060

Does the extracorporeal circulation worsen anemia in hemodialysis patients? Investigation with advanced microscopes of red blood cells drawn at the beginning and end of dialysis.

PubMed

Stamopoulos, Dimosthenis; Bakirtzi, Nerantzoula; Manios, Efthymios; Grapsa, Eirini

2013-01-01

In hemodialysis (HD) patients, anemia relates to three main factors: insufficient production of erythropoietin; impaired management of iron; and decreased lifespan of red blood cells (RBCs). The third factor can relate to structural deterioration of RBCs due to extrinsic (extracorporeal circuit; biochemical activation and/or mechanical stress during dialysis) and intrinsic (uremic milieu; biochemical interference of the RBC membrane constituents with toxins) mechanisms. Herein, we evaluate information accessed with advanced imaging techniques at the cellular level. Atomic force and scanning electron microscopes were employed to survey intact RBCs (iRBCs) of seven HD patients in comparison to seven healthy donors. The extrinsic factor was investigated by contrasting pre- and post-HD samples. The intrinsic environment was investigated by comparing the microscopy data with the clinical ones. The iRBC membranes of the enrolled HD patients were overpopulated with orifice-like (high incidence; typical size within 100-1,000 nm) and crevice-like (low incidence; typical size within 500-4,000 nm) defects that exhibited a statistically significant (P < 0.05) relative increase (+55% and +350%, respectively) in respect to healthy donors. The relative variation of the orifice and crevice indices (mean population of orifices and crevices per top membrane surface) between pre- and post-HD was not statistically significant (-3.3% and +4.5%, respectively). The orifice index correlates with the concentrations of urea, calcium, and phosphorus, but not, however, with that of creatinine. Extracorporeal circulation is not detrimental to the structural integrity of RBC membranes. Uremic milieu is a candidate cause of RBC membrane deterioration, which possibly worsens anemia.

Does the extracorporeal circulation worsen anemia in hemodialysis patients? Investigation with advanced microscopes of red blood cells drawn at the beginning and end of dialysis

PubMed Central

Stamopoulos, Dimosthenis; Bakirtzi, Nerantzoula; Manios, Efthymios; Grapsa, Eirini

2013-01-01

Background In hemodialysis (HD) patients, anemia relates to three main factors: insufficient production of erythropoietin; impaired management of iron; and decreased lifespan of red blood cells (RBCs). The third factor can relate to structural deterioration of RBCs due to extrinsic (extracorporeal circuit; biochemical activation and/or mechanical stress during dialysis) and intrinsic (uremic milieu; biochemical interference of the RBC membrane constituents with toxins) mechanisms. Herein, we evaluate information accessed with advanced imaging techniques at the cellular level. Methods Atomic force and scanning electron microscopes were employed to survey intact RBCs (iRBCs) of seven HD patients in comparison to seven healthy donors. The extrinsic factor was investigated by contrasting pre- and post-HD samples. The intrinsic environment was investigated by comparing the microscopy data with the clinical ones. Results The iRBC membranes of the enrolled HD patients were overpopulated with orifice-like (high incidence; typical size within 100–1,000 nm) and crevice-like (low incidence; typical size within 500–4,000 nm) defects that exhibited a statistically significant (P < 0.05) relative increase (+55% and +350%, respectively) in respect to healthy donors. The relative variation of the orifice and crevice indices (mean population of orifices and crevices per top membrane surface) between pre- and post-HD was not statistically significant (−3.3% and +4.5%, respectively). The orifice index correlates with the concentrations of urea, calcium, and phosphorus, but not, however, with that of creatinine. Conclusion Extracorporeal circulation is not detrimental to the structural integrity of RBC membranes. Uremic milieu is a candidate cause of RBC membrane deterioration, which possibly worsens anemia. PMID:24143093

THE DISTRIBUTION OF CHLORPYRIFOS FOLLOWING A CRACK AND CREVICE TYPE APPLICATION IN THE U.S. EPA INDOOR AIR QUALITY RESEARCH HOUSE

EPA Science Inventory

A study was conducted in the U.S. EPA Indoor Air Quality Research House to determine the spatial and temporal distribution of chlorpyrifos following a professional crack and crevice application in the kitchen. Following the application, measurements were made in the kitchen, de...

THE DISTRIBUTION OF CHLORPYRIFOS FOLLOWING A CRACK AND CREVICE TYPE APPLICATION IN THE U.S. EPA INDOOR AIR QUALITY RESEARCH HOUSE

EPA Science Inventory

The paper gives results of a study to determine the spatial and temporal distribution of chlorpyrifos following a professional crack-and-crevice application in the kitchen of the U.S. EPA's indoor air quality research house in North Carolina. Following the application, measuremen...

THE DISTRIBUTION OF CHLORPYRIFOS FOLLOWING A CRACK AND CREVICE TYPE APPLICATION IN THE U.S. EPA INDOOR AIR QUALITY TEST HOUSE

EPA Science Inventory

A study was conducted in the U.S. EPA Indoor Air Quality Test House to determine the spatial and temporal distribution of chlorpyrifos following a professional crack and crevice application in the kitchen. Following the application, measurements were made in the kitchen, den a...

Disruption of a hydrogen bond network in human versus spider monkey cytochrome c affects heme crevice stability.

PubMed

Goldes, Matthew E; Jeakins-Cooley, Margaret E; McClelland, Levi J; Mou, Tung-Chung; Bowler, Bruce E

2016-05-01

The hypothesis that the recent rapid evolution of primate cytochromes c, which primarily involves residues in the least stable Ω-loop (Ω-loop C, residues 40-57), stabilizes the heme crevice of cytochrome c relative to other mammals, is tested. To accomplish this goal, we have compared the properties of human and spider monkey cytochrome c and a set of four variants produced in the process of converting human cytochrome c into spider monkey cytochrome c. The global stability of all variants has been measured by guanidine hydrochloride denaturation. The stability of the heme crevice has been assessed with the alkaline conformational transition. Structural insight into the effects of the five amino acid substitutions needed to convert human cytochrome c into spider monkey cytochrome c is provided by a 1.15Å resolution structure of spider monkey cytochrome c. The global stability for all variants is near 9.0kcal/mol at 25°C and pH7, which is higher than that observed for other mammalian cytochromes c. The heme crevice stability is more sensitive to the substitutions required to produce spider monkey cytochrome c with decreases of up to 0.5 units in the apparent pKa of the alkaline conformational transition relative to human cytochrome c. The structure of spider monkey cytochrome c indicates that the Y46F substitution destabilizes the heme crevice by disrupting an extensive hydrogen bond network that connects three surface loops including Ω-loop D (residues 70-85), which contains the Met80 heme ligand. Copyright © 2015 Elsevier Inc. All rights reserved.

Marine Corrosion.

DTIC Science & Technology

1985-04-24

cor- rosion resistant alloys such as molybdenum -containing stainless steels. For the latter the high degree of aeration in the splashing water...imposed by marine technology, such as elevated temperatures , tensile stresses, cyclic stresses, severe (tight) crevices, galvanic coupling and high ...corrosion in seawater in tight metal-to-non-metal crevices are titanium alloys 4, the high molybdenum nickel base alloys Hastelloy alloy C-276 and

Basking and torpor in a rock-dwelling desert marsupial: survival strategies in a resource-poor environment.

PubMed

Geiser, Fritz; Pavey, Chris R

2007-11-01

Australian deserts are characterized by unpredictability, low primary productivity, and high temperature fluctuations. Despite these adverse conditions the diversity of small insectivorous marsupials of the family Dasyuridae is surprisingly high. We quantified the thermal biology of the dasyurid Pseudantechinus madonnellensis (body mass approximately 30 g) in the wild to gain some understanding of whether the success of dasyurids in the arid zone may be related to some extent to their use of energy conservation strategies. In winter, most free-ranging Pseudantechinus frequently (58.3% of 131 animal days) entered daily torpor after midnight (mean 0157 hours) in rock crevices when outside ambient temperatures (T (a)) were low. Most animals remained torpid until the next morning when they moved while still torpid from rock crevices to sun-exposed basking sites. We visually observed basking during rewarming from torpor (mean commencement at 0943 hours) at body temperatures (T (b)) as low as 19.3 degrees C when radiant heat was high and T (a) was rising. Basking continued for the rest of the day. Torpor use was not strongly correlated with T (a), but the temporal organization of daily torpor and activity were apparently linked to the thermal characteristics of basking sites. Our study suggests that by frequently employing daily torpor and basking and by appropriately coordinating their thermal biology with that of specific locations in their environment, Pseudantechinus can reduce daily energy expenditure and thus can live and reproduce in a challenging environment. It is likely that the success of other small dasyurids and perhaps many other small mammals living in deserts is linked to employment of torpor and basking for energy conservation.

Roost selection by western long-eared myotis (Myotis evotis) in burned and unburned piñon–juniper woodlands of southwestern Colorado

USGS Publications Warehouse

Snider, E. Apple; Cryan, Paul M.; Wilson, Kenneth R.

2013-01-01

All 16 species of bats known to occur in western Colorado are found at Mesa Verde National Park (MVNP) in the southwestern United States. Since 1996, wildfires have burned more than 70% of MVNP (> 15,000 ha), potentially altering food and roosting resources for bats. During the summers of 2006–2007, we investigated roost use by reproductive female western long-eared myotis (Myotis evotis). We located 33 bat roosts in rock crevices and 1 in a juniper snag. All but 2 of the roosts were in unburned habitat. Bats roosted alone or in small groups (≤3 individuals) and switched roosts frequently (1–7 roosts per bat, median = 1.5 roosts per bat, SE = 0.5 roosts per bat). We compared occupied roosts with randomly selected unoccupied crevices and used an information theoretic approach to determine which variables were most important in determining roost use at microhabitat and landscape scales. At the microhabitat scale, maternity roosts were higher above the ground and deeper than random, unoccupied rock crevices. At the landscape scale, roosts were closer to water and farther from burned habitat than random crevices, providing reproductive female M. evotis with the best opportunities to drink and forage for insects. Tree roosts are apparently not a vital resource for reproductive female M. evotis during the summer months at our study site, presumably because of the extensive availability of rock crevices. Understanding site-specific roosting behavior is important for proper management of bat populations because differences can exist between geographic regions, even among areas with similar plant communities.

Characterization of the corrosion protection mechanism of cerium-based conversion coatings on high strength aluminum alloys

NASA Astrophysics Data System (ADS)

Pinc, William Ross

The aim of the work presented in this dissertation is to investigate the corrosion protection mechanism of cerium-based conversion coatings (CeCCs) used in the corrosion protection of high strength aluminum alloys. The corrosion resistance of CeCCs involves two general mechanisms; barrier and active. The barrier protection mechanism was influenced by processing parameters, specifically surface preparation, post-treatment, and the use of gelatin. Post-treatment and the addition of gelatin to the coating solution resulted in fewer cracks and transformation of the coating to CePO4, which increased the corrosion resistance by improving the barrier aspect of CeCCs. CeCCs were found to best act as barriers when crack size was limited and CePO4 was present in the coating. CeCCs were found to protect areas of the substrate that were exposed in the coating, indicating that the coatings were more than simple barriers. CeCCs contained large cracks, underneath which subsurface crevices were connected to the surface by the cracks. Despite the observation that no cerium was present in crevices, coatings with crevices exhibited significant corrosion protection. The impedance of post-treated coatings with crevices increased during salt spray exposure. The increase in impedance was associated with the formation of protective oxides / hydroxides; however, crevice-free coatings also exhibited active protection leading to the conclusion that the formation of interfacial layers between the CeCC and the substrate also contributed to the active protection. Based on the overall results of the study, the optimal corrosion protection of CeCCs occurred when processing conditions produced coatings with morphologies and compositions that facilitated both the barrier and active protection mechanisms.

Influence of Chloride Ion and Temperature on the Corrosion Behavior of Ni-Fe-Cr Alloy 028

NASA Astrophysics Data System (ADS)

Zhang, L. N.; Dong, J. X.; Szpunar, J. A.; Zhang, M. C.; Basu, R.

Recently, the working condition of tubing systems used in oil and natural gas industries are severer than before with the increasing exploitation of acidic gas fields. The corrosion problems induced from the corrosive environment with chloride ion medium and high temperature have been much more concerned. The presence of chloride ion can accelerate the dissolution of metals. The corrosion performance is also sensitive to the operating temperature. Classic localized corrosions such as the pitting or the crevice type due to environmental temperature and chloride ion.

Great Lakes Regional Phase 3 Commercialization Conference, Held in Detroit, Michigan on May 23 - 25, 1994

DTIC Science & Technology

1994-05-25

small highly efficient power systems to provide electricity for space applications. These converters are solar heated for near earth orbit applications...processing in NASA’s Wake Shield Facility. AMPS plans to complete product development in each of these specific technology areas utilizing SBIR...Corrosion: Crevice corrosion is a form of localized corrosion that occurs within crevices or shielded surfaces where stagnant solution is present

Laboratory Investigation of a Leaking Type 316 Socket Weld in a Boron Injection Tank Sampling Line

NASA Astrophysics Data System (ADS)

Xu, Hongqing; Fyfitch, Steve; Hosier, Ryan; Hyres, James

A leak was discovered in a Type 316 stainless steel socket weld in the sampling line for the boron injection tank. A section of the pipeline containing the leaking weld was removed for laboratory investigation that included visual and Stereovisual inspections, liquid penetrant (PT) testing, metallography, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and ferrite content determinations. The leak path was a through-wall transgranular crack in the socket weld. Cracking initiated along the weld-metal-to-base-metal interface at the tip of the crevice between the socket and pipe. The crevice was exposed to oxygenated boron solution at <180°F. Shallow intergranular attack (IGA) was found in the exposed base metal inside the crevice. Based on the investigation results, it was concluded that transgranular stress corrosion cracking (TGSCC) is the primary cracking mechanism.

Sensitivity of coral recruitment to subtle shifts in early community succession.

PubMed

Doropoulos, Christopher; Roff, George; Visser, Mart-Simone; Mumby, Peter J

2017-02-01

Community succession following disturbance depends on positive and negative interactions, the strength of which change along environmental gradients. To investigate how early succession affects coral reef recovery, we conducted an 18-month experiment in Palau, using recruitment tiles and herbivore exclusion cages. One set of reefs has higher wave exposure and had previously undergone a phase shift to macroalgae following a major typhoon, whereas the other set of reefs have lower wave exposure and did not undergo a macroalgal phase shift. Similar successional trajectories were observed at all sites when herbivores were excluded: turf algae dominated early succession, followed by shifts to foliose macroalgae and heterotrophic invertebrates. However, trajectories differed in the presence of herbivores. At low wave exposure reefs, herbivores promoted coralline algae and limited turf and encrusting fleshy algae in crevice microhabitats, facilitating optimal coral recruitment. Under medium wave exposure, relatively higher but still low coverage of turf and encrusting fleshy algae (15-25%) found in crevice microhabitats inhibited coral recruitment, persisting throughout multiple recruitment events. Our results indicate that altered interaction strength in different wave environments following disturbance can drive subtle changes in early succession that cascade to alter secondary succession to coral recruitment and system recovery. © 2016 by the Ecological Society of America.

Monitoring planktivorous seabird populations: Validating surface counts of crevice-nesting auklets using mark-resight techniques

USGS Publications Warehouse

Sheffield, L.M.; Gall, Adrian E.; Roby, D.D.; Irons, D.B.; Dugger, K.M.

2006-01-01

Least Auklets (Aethia pusilla (Pallas, 1811)) are the most abundant species of seabird in the Bering Sea and offer a relatively efficient means of monitoring secondary productivity in the marine environment. Counting auklets on surface plots is the primary method used to track changes in numbers of these crevice-nesters, but counts can be highly variable and may not be representative of the number of nesting individuals. We compared average maximum counts of Least Auklets on surface plots with density estimates based on mark–resight data at a colony on St. Lawrence Island, Alaska, during 2001–2004. Estimates of breeding auklet abundance from mark–resight averaged 8 times greater than those from maximum surface counts. Our results also indicate that average maximum surface counts are poor indicators of breeding auklet abundance and do not vary consistently with auklet nesting density across the breeding colony. Estimates of Least Auklet abundance from mark–resight were sufficiently precise to meet management goals for tracking changes in seabird populations. We recommend establishing multiple permanent banding plots for mark–resight studies on colonies selected for intensive long-term monitoring. Mark–resight is more likely to detect biologically significant changes in size of auklet breeding colonies than traditional surface count techniques.

Anode for a secondary, high-temperature electrochemical cell

DOEpatents

Vissers, Donald R.; Tani, Benjamin S.

1976-01-01

A high-temperature, secondary electrochemical cell includes an anode containing lithium, an electrolyte containing lithium ions and a cathode containing a chalcogen material such as sulfur or a metallic sulfide. The anode includes a porous substrate formed of, for instance, a compacted mass of entangled metallic fibers providing interstitial crevices for receiving molten lithium metal. The surfaces of the interstitial crevices are provided with a coating of cobalt metal to enhance the retention of the molten lithium metal within the substrate.

Conversion of transuranic waste to low level waste by decontamination: a technical and economic evaluation

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

Allen, R.P.; Hazelton, R.F.

1984-12-01

A study was conducted to evaluate the technical and economic feasibility of using in-situ decontamination techniques to convert glove boxes and other large TRU-contaminated components directly into LLW. The results of the technical evaluation indicate that in-situ decontamination of these types of components to non-TRU levels is technically feasible. Applicable decontamination techniques include electropolishing, hand scrubbing, chemical washes/sprays, strippable coatings and Freon spray-cleaning. The removal of contamination from crevices and other holdup areas remains a problem, but may be solved through further advances in decontamination technology. Also, the increase in the allowable maximum TRU level from 10 nCi/g to 100more » nCi/g as defined in DOE Order 5820.2 reduces the removal requirement and facilitates measurement of the remaining quantities. The major emphasis of the study was on a cost/benefit evaluation that included a review and update of previous analyses and evaluations of TRU-waste volume reduction and conversion options. The results of the economic evaluation show, for the assumptions used, that there is a definite cost incentive to size reduce large components, and that decontamination of sectioned material has become cost competitive with the size reduction options. In-situ decontamination appears to be the lowest cost option when based on routine-type operations conducted by well-trained and properly equipped personnel. 16 references, 1 figure, 7 tables.« less

Earthquakes Promote Bacterial Genetic Exchange in Serpentinite Crevices

NASA Astrophysics Data System (ADS)

Naoto, Yoshida; Fujiura, Nori

2009-04-01

We report the results of our efforts to study the effects of seismic shaking on simulated biofilms within serpentinite fissures. A colloidal solution consisting of recipient bacterial cells (Pseudomonas sp. or Bacillus subtilis), donor plasmid DNA encoded for antibiotic resistance, and chrysotile (an acicular clay mineral that forms in crevices of serpentinite layers) were placed onto an elastic body made from gellan gum, which acted as the biofilm matrix. Silica beads, as rock analogues (i.e., chemically inert mechanical serpentinite), were placed on the gellan surface, which was coated with the colloidal solution. A rolling vibration similar to vibrations generated by earthquakes was applied, and the silica beads moved randomly across the surface of the gellan. This resulted in the recipient cells' acquiring plasmid DNA and thus becoming genetically transformed to demonstrate marked antibiotic resistance. Neither Pseudomonas sp. nor B. subtilis were transformed by plasmid DNA when chrysotile was substituted for by kaolinite or bentonite in the colloidal solution. Tough gellan (1.0%) promoted the introduction of plasmid DNA into Pseudomonas sp., but soft gellan (0.3%) had no such effect. Genetic transformation of bacteria on the surface of gellan by exposure to exogenous plasmid DNA required seismic shaking and exposure to the acicular clay mineral chrysotile. These experimental results suggest that bacterial genetic exchange readily occurs when biofilms that form in crevices of serpentinite are exposed to seismic shaking. Seismic activity may be a key factor in bacterial evolution along with the formation of biofilms within crevices of serpentinite.

Aerodynamics inside a rapid compression machine

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

Mittal, Gaurav; Sung, Chih-Jen

2006-04-15

The aerodynamics inside a rapid compression machine after the end of compression is investigated using planar laser-induced fluorescence (PLIF) of acetone. To study the effect of reaction chamber configuration on the resulting aerodynamics and temperature field, experiments are conducted and compared using a creviced piston and a flat piston under varying conditions. Results show that the flat piston design leads to significant mixing of the cold vortex with the hot core region, which causes alternate hot and cold regions inside the combustion chamber. At higher pressures, the effect of the vortex is reduced. The creviced piston head configuration is demonstratedmore » to result in drastic reduction of the effect of the vortex. Experimental conditions are also simulated using the Star-CD computational fluid dynamics package. Computed results closely match with experimental observation. Numerical results indicate that with a flat piston design, gas velocity after compression is very high and the core region shrinks quickly due to rapid entrainment of cold gases. Whereas, for a creviced piston head design, gas velocity after compression is significantly lower and the core region remains unaffected for a long duration. As a consequence, for the flat piston, adiabatic core assumption can significantly overpredict the maximum temperature after the end of compression. For the creviced piston, the adiabatic core assumption is found to be valid even up to 100 ms after compression. This work therefore experimentally and numerically substantiates the importance of piston head design for achieving a homogeneous core region inside a rapid compression machine. (author)« less

Investigation of Stainless Steel Corrosion in Ultrahigh-Purity Water and Steam Systems by Surface Analytical Techniques

NASA Astrophysics Data System (ADS)

Dong, Xia; Iacocca, Ronald G.; Bustard, Bethany L.; Kemp, Craig A. J.

2010-02-01

Stainless steel pipes with different degrees of rouging and a Teflon®-coated rupture disc with severe corrosion were thoroughly investigated by combining multiple surface analytical techniques. The surface roughness and iron oxide layer thickness increase with increasing rouge severity, and the chromium oxide layer coexists with the iron oxide layer in samples with various degrees of rouging. Unlike the rouging observed for stainless steel pipes, the fast degradation of the rupture disc was caused by a crevice corrosion environment created by perforations in the protective Teflon coating. This failure analysis clearly shows the highly corrosive nature of ultrapure water used in the manufacture of pharmaceutical products, and demonstrates some of the unexpected corrosion mechanisms that can be encountered in these environments.

Socket welds in nuclear facilities

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

Anderson, P.A.; Torres, L.L.

1995-12-31

Socket welds are easier and faster to make than are butt welds. However, they are often not used in nuclear facilities because the crevices between the pipes and the socket sleeves may be subject to crevice corrosion. If socket welds can be qualified for wider use in facilities that process nuclear materials, the radiation exposures to welders can be significantly reduced. The current tests at the Idaho Chemical Processing Plant (ICPP) are designed to determine if socket welds can be qualified for use in the waste processing system at a nuclear fuel processing plant.

Investigation of Local Hydrogen Uptake in Rescaled Model Occluded Sites Using Crevice Scaling Laws

DTIC Science & Technology

2005-04-01

13- 8 Mo . Under anodic polarization, there is a combination of x and G in a crevice or crack where the stainless steel would be passive and remain...2004). 8 . G.A. Young, Jr., J.R. Scully, "The Effects of Test Temperature , Temper and Alloyed Copper on Hydrogen Controlled Crack Growth of an A1-Zn-Mg...sharp crack tip.[16] Precipitation-aged hardened martensitic stainless steels (i.e., Fe-Cr-Ni- Mo alloys) that release hydrolysable Cr and Fe cations

Consequences of volcanic ash deposition on the locomotor performance of the Phymaturus spectabilis lizard from Patagonia, Argentina.

PubMed

Cabezas-Cartes, Facundo; Kubisch, Erika Leticia; Ibargüengoytía, Nora Ruth

2014-03-01

The locomotor performance of lizards depends on their morphological and physiological adaptations to the habitat. However, when the habitat changes dramatically, for example, by a volcanic eruption, the performance of lizards may be affected. We registered the vegetation cover, the surface covered by ash, the presence of crevices suitable for Phymaturus and the rocks slopes to analyze the effects of ash accumulation produced by the eruption of Puyehue-Cordon Caulle volcanic complex on microhabitat use and availability of the Phymaturus spectabilis lizard. In addition, we studied the effect of ashes and slope on the locomotor performance of P. spectabilis by registering the maximum speed in sprint runs and long runs under four different treatments (cork and on the level, ashes and on the level, cork and slope, and ashes and slope). P. spectabilis selected microhabitats unvegetated, with crevices and steep slopes. Regarding locomotor performance, the speed of lizards was negatively affected by the presence of ash only in sprint runs on the level and in long runs with slope. The slope had a negative impact on the speed in all the treatments. These results show that the presence of volcanic ashes in the substrate might have affected the locomotor performance of the lizards, especially in long runs, and hence, the interaction of individuals with the environment, that is, escaping from predators and social behavior. © 2013 Wiley Periodicals, Inc.

Micro-topography mediates interactions between corals, algae, and herbivorous fishes on coral reefs

NASA Astrophysics Data System (ADS)

Brandl, S. J.; Hoey, A. S.; Bellwood, D. R.

2014-06-01

Processes occurring during the early life stages of corals are important for the replenishment of coral assemblages and the resilience of coral reefs. However, the factors influencing early life stages of corals are not well understood, and the role of micro-topographic complexity for habitat associations of juvenile corals is largely unexplored. This study investigated the microhabitat distribution patterns of early life stages of corals and a potential macroalgal competitor ( Turbinaria ornata) across two reef zones (reef crest and outer reef flat) on Lizard Island, Great Barrier Reef. In both reef zones, both corals and T. ornata were significantly more abundant in concealed microhabitats than in semi-concealed or open microhabitats (GLMM: P < 0.001). The prevalence of juvenile corals and T. ornata within concealed environments suggests that they might be effective refuges from grazing by herbivorous fishes. The density of juvenile corals was positively related, and density of T. ornata negatively related to the abundance of two groups of herbivorous fishes, pairing rabbitfishes, and surgeonfishes in the genus Zebrasoma (BEST ENV-BIO: r s = 0.72, P < 0.01), which feed in concealed microhabitats. This correlative evidence suggests that crevices may be important for early life stages of both coral and macroalgae, and that a specific suite of crevice-feeding fishes may influence benthic community dynamics in these microhabitats.

Technological capabilities of surface layers formation on implant made of Ti-6Al-4V ELI alloy.

PubMed

Kiel-Jamrozik, Marta; Szewczenko, Janusz; Basiaga, Marcin; Nowińska, Katarzyna

2015-01-01

The aim of the presented research was to find a combination of surface modification methods of implants made of the Ti-6Al-4V ELI alloy, that lead to formation of effective barrier for metallic ions that may infiltrate into solution. To this end, the following tests were carried out: roughness measurement, the voltamperometric tests (potentiodynamic and potentiostatic), and the ion infiltration test. The electropolishing process resulted in the lowering of surface roughness in comparison with mechanical treatment of the surface layer. The anodization process and steam sterilization increased corrosion resistance regardless of the mechanical treatment or electropolishing. The crevice corrosion tests revealed that independent of the modification method applied, the Ti-6Al-4V ELI alloy has excellent crevice corrosion resistance. The smallest quantity of ions infiltrated to the solution was observed for surface modification consisting in the mechanical treatment and anodization with the potential of 97 V. Electric parameters deter- mined during studies were the basis for effectiveness estimation of particular surface treatment methods. The research has shown that the anodization process significantly influences the pitting corrosion resistance of the Ti-6Al-4V ELI alloy independent of the previous surface treatment methods (mechanical and electrochemical). The surface layer after such modification is a protective barrier for metallic ions infiltrated to solution and protects titanium alloy against corrosive environment influence.

Characterisation of Crevice and Pit Solution Chemistries Using Capillary Electrophoresis with Contactless Conductivity Detector

PubMed Central

Nie, Mengyan; Wharton, Julian A.; Cranny, Andy; Harris, Nick R.; Wood, Robert J.K.; Stokes, Keith R.

2013-01-01

The ability to predict structural degradation in-service is often limited by a lack of understanding of the evolving chemical species occurring within a range of different microenvironments associated with corrosion sites. Capillary electrophoresis (CE) is capable of analysing nanolitre solution volumes with widely disparate concentrations of ionic species, thereby producing accurate and reliable results for the analysis of the chemical compositions found within microenvironment corrosion solutions, such as those found at crevice and pit corrosion sites. In this study, CE with contactless conductivity detection (CCD) has been used to characterize pitting and crevice corrosion solution chemistries for the first time. By using the capillary electrophoresis with contactless conductivity detection (CE-CCD) system, direct and simultaneous detection of seven metal cations (Cu2+, Ni2+, Fe3+, Fe2+, Cr3+, Mn2+, and Al3+) and chloride anions was achieved with a buffer solution of 10 mM 2,6-pyridinedicarboxylic acid and 0.5 mM cetyltrimethylammonium hydroxide at pH 4 using a pre-column complexation method. The detection limits obtained for the metal cations and chloride anions were 100 and 10 ppb, respectively. The CE-CCD methodology has been demonstrated to be a versatile technique capable of speciation and quantifying the ionic species generated within artificial pit (a pencil electrode) and crevice corrosion geometries for carbon steels and nickel-aluminium bronze, thus allowing the evolution of the solution chemistry to be assessed with time and the identification of the key corrosion analyte targets for structural health monitoring. PMID:28788335

Initiation criteria for crevice corrosion of titanium alloys used for HLW disposal overpack

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

Akashi, Masatsune; Nakayama, Guen; Fukuda, Takanori

1998-12-31

The overpack that geologically stores the canisters containing vitrified high-level radioactive waste (HLW) for super-long term disposal is demanded of being able to hold the canisters securely for at least 1,000 years. For such a service, the greatest as well as essentially the sole factor that can mar the overpack`s working is corrosion by the groundwater. This paper discusses the notion and the methodology to prove for overpacks made of titanium (Ti) alloys that they are capable of stably maintaining the state of passivity indefinitely long time so as to be immune to the initiation of localized corrosion. it ismore » shown that (1) the critical potential for corrosion-crevice initiation, V{sub C,CREV}, can be substituted rationally by the corrosion-crevice repassivation potential, E{sub R,CREV}, which can be determined by the cyclic polarization test, and (2) the limits of safety usage of Ti alloys can be determined quantitatively by comparing E{sub R,CREV} and E{sub SP}, the steady-state corrosion potential.« less

Partial-Vacuum-Gasketed Electrochemical Corrosion Cell

NASA Technical Reports Server (NTRS)

Bonifas, Andrew P.; Calle, Luz M.; Hintze, Paul E.

2006-01-01

An electrochemical cell for making corrosion measurements has been designed to prevent or reduce crevice corrosion, which is a common source of error in prior such cells. The present cell (see figure) includes an electrolyte reservoir with O-ring-edged opening at the bottom. In preparation for a test, the reservoir, while empty, is pressed down against a horizontal specimen surface to form an O-ring seal. A purge of air or other suitable gas is begun in the reservoir, and the pressure in the reservoir is regulated to maintain a partial vacuum. While maintaining the purge and partial vacuum, and without opening the interior of the reservoir to the atmosphere, the electrolyte is pumped into the reservoir. The reservoir is then slowly lifted a short distance off the specimen. The level of the partial vacuum is chosen such that the differential pressure is just sufficient to keep the electrolyte from flowing out of the reservoir through the small O-ring/specimen gap. Electrochemical measurements are then made. Because there is no gasket (and, hence, no crevice between the specimen and the gasket), crevice corrosion is unlikely to occur.

Review of corrosion in 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders

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

Lykins, M.L.

1995-08-01

A literature review was conducted to determine the type, extent and severity of corrosion found in the 10- and 14-ton mild steel depleted UF{sub 6} storage cylinders. Also discussed in this review is corrosion found in the valves and plugs used in the cylinders. Corrosion of the cylinders is a gradual process which occurs slowly over time. Understanding corrosion of the cylinders is an important concern for long term storage of the UF{sub 6} in the cylinder yards, as well as the final disposition of the depleted UF{sub 6} tails inventory in the future. The following conclusions are made frommore » the literature review: (1) The general external corrosion rate of the cylinders is about 1 to 2 mils per year (1 mil = 0.001{double_prime}). The highest general external corrosion rate was over 5 mpy on the 48G type cylinders. (2) General internal corrosion from the depleted UF{sub 6} is negligible under normal storage conditions. Crevice corrosion can occur at the cylinder/saddle interface from the retention of water in this area. Crevice corrosion can occur at the cylinder/skirt interface on the older skirted cylinders due to the lack of water drainage in this area. Crevice corrosion can occur on cylinders that have been in ground contact. Crevice corrosion and galvanic corrosion can occur where the stainless steel I.D. nameplates are attached to the cylinder. The packing nuts on the bronze one-inch valves used in the cylinders are susceptible to stress corrosion cracking (SCC). Mechanical damage from routine handling can lead to a breach in a cylinder with subsequent accelerated corrosion of the mild steel due to attack from HF and other UF{sub 6} hydrolysis by-products.« less

ECLSS Universal Waste Management System (UWMS) Metal Materials Compatibility Study- Electrochemical and Crevice Corrosion Evaluation

NASA Technical Reports Server (NTRS)

Lee, R. E.

2017-01-01

Electrochemical and crevice corrosion laboratory test results are presented for three noble metal candidates with possible application on the Universal Waste Management System (UWMS) in support of the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). The three metal candidates, which included Inconel 625, Hastelloy C276 and Titanium 6Al-4V, were evaluated in two solutions representative of the acidic pretreatment formulations utilized during processing of waste liquids within the ECLSS. Final test results and data analysis indicated that the passive layer on all three metals provides excellent corrosion protection in both solutions under standard test conditions.

Prediction of Failure Due to Thermal Aging, Corrosion and Environmental Fracture in Amorphous and Titanium Alloys

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

Farmer, J C

2003-04-15

DARPA is exploring a number of advanced materials for military applications, including amorphous metals and titanium-based alloys. Equipment made from these materials can undergo degradation due to thermal aging, uniform corrosion, pitting, crevice corrosion, denting, stress corrosion cracking, corrosion fatigue, hydrogen induced cracking and microbial influenced corrosion. Amorphous alloys have exceptional resistance to corrosion, due in part to the absence of grain boundaries, but can undergo crystallization and other phase instabilities during heating and welding. Titanium alloys are extremely corrosion resistant due to the formation of a tenacious passive film of titanium oxide, but is prone to hydrogen absorption inmore » crevices, and hydrogen induced cracking after hydrogen absorption. Accurate predictions of equipment reliability, necessary for strategic planning, requires integrated models that account for all relevant modes of attack, and that can make probabilistic predictions. Once developed, model parameters must be determined experimentally, and the validity of models must be established through careful laboratory and field tests. Such validation testing requires state-of-the-art surface analytical techniques, as well as electrochemical and fracture mechanics tests. The interaction between those processes that perturb the local environment on a surface and those that alter metallurgical condition must be integrated in predictive models. The material and environment come together to drive various modes of corrosive attack (Figure 1). Models must be supported through comprehensive materials testing capabilities. Such capabilities are available at LLNL and include: the Long Term Corrosion Test Facility (LTCTF) where large numbers of standard samples can be exposed to realistic test media at several temperature levels; a reverse DC machine that can be used to monitor the propagation of stress corrosion cracking (SCC) in situ; and banks of potentiostats with temperature controlled cells for potentiostatic and potentiodynamic testing (Figure 2).« less

Periodontitis and periimplantitis: one and the same?

PubMed

Meffert, R M

1993-12-01

Research shows that the same anaerobic, gram-negative pathogens are present in the periodontal and implant pocket or crevice. The implants in a partially edentulous case are probably more at risk due to the bacteria being more pathogenic and a seeding mechanism from the tooth pocket to the implant crevice. In the face of a normal microbial flora, retrograde periimplantitis or radiographic bone loss without gingival changes may be due to trauma because of overloading, loading too soon, and/or loading in a lateral direction. Finally, the combination of an infective process (periimplantitis) and noninfective or traumatic process (retrograde periimplantitis) will result in rapid osseous destruction and, possibly, loss of the implant fixture(s).

A Composite Depth Scale for Sediments from Crevice Lake, Montana

USGS Publications Warehouse

Rosenbaum, J.G.; Skipp, G.; Honke, J.; Chapman, C.

2010-01-01

As part of a study to derive records of past environmental change from lake sediments in the western United States, a set of cores was collected from Crevice Lake, Montana, in late February and early March 2001. Crevice Lake (latitude 45.000N, longitude 110.578W, elevation 1,713 meters) lies adjacent to the Yellowstone River at the north edge of Yellowstone National Park. The lake is more than 31 meters deep and has a surface area of 7.76 hectares. The combination of small surface area and significant depth promote anoxic bottom-water conditions that preserve annual laminations (varves) in the sediment. Three types of cores were collected through the ice. The uppermost sediments were obtained in freeze cores that preserved the sediment water interface. Two sites were cored with a 5-centimeter diameter corer. Five cores were taken with a 2-meter-long percussion piston corer. The percussion core uses a plastic core liner with an inside diameter of 9 centimeters. Coring was done at two sites. Because of the relatively large diameter of the percussion cores, samples from these cores were used for a variety of analyses including pollen, charcoal, diatoms, stable isotopes, organic and inorganic carbon, elemental analyses, and magnetic properties.

Density-dependent coral recruitment displays divergent responses during distinct early life-history stages

PubMed Central

Evensen, Nicolas R.; Gómez-Lemos, Luis A.; Babcock, Russell C.

2017-01-01

Population growth involves demographic bottlenecks that regulate recruitment success during various early life-history stages. The success of each early life-history stage can vary in response to population density, interacting with intrinsic (e.g. behavioural) and environmental (e.g. competition, predation) factors. Here, we used the common reef-building coral Acropora millepora to investigate how density-dependence influences larval survival and settlement in laboratory experiments that isolated intrinsic effects, and post-settlement survival in a field experiment that examined interactions with environmental factors. Larval survival was exceptionally high (greater than 80%) and density-independent from 2.5 to 12 days following spawning. By contrast, there was a weak positive effect of larval density on settlement, driven by gregarious behaviour at the highest density. When larval supply was saturated, settlement was three times higher in crevices compared with exposed microhabitats, but a negative relationship between settler density and post-settlement survival in crevices and density-independent survival on exposed surfaces resulted in similar recruit densities just one month following settlement. Moreover, a negative relationship was found between turf algae and settler survival in crevices, whereas gregarious settlement improved settler survival on exposed surfaces. Overall, our findings reveal divergent responses by coral larvae and newly settled recruits to density-dependent regulation, mediated by intrinsic and environmental interactions. PMID:28573015

Mitigating Localized Corrosion Using Thermally Sprayed Aluminum (TSA) Coatings on Welded 25% Cr Superduplex Stainless Steel

NASA Astrophysics Data System (ADS)

Paul, S.; Lu, Q.; Harvey, M. D. F.

2015-04-01

Thermally sprayed aluminum (TSA) coating has been increasingly used for the protection of carbon steel offshore structures, topside equipment, and flowlines/pipelines exposed to both marine atmospheres and seawater immersion conditions. In this paper, the effectiveness of TSA coatings in preventing localized corrosion, such as pitting and crevice corrosion of 25% Cr superduplex stainless steel (SDSS) in subsea applications, has been investigated. Welded 25% Cr SDSS (coated and uncoated) with and without defects, and surfaces coated with epoxy paint were also examined. Pitting and crevice corrosion tests, on welded 25% Cr SDSS specimens with and without TSA/epoxy coatings, were conducted in recirculated, aerated, and synthetic seawater at 90 °C for 90 days. The tests were carried out at both the free corrosion potentials and an applied cathodic potential of -1100 mV saturated calomel electrode. The acidity (pH) of the test solution was monitored daily and adjusted to between pH 7.5 and 8.1, using dilute HCl solution or dilute NaOH, depending on the pH of the solution measured during the test. The test results demonstrated that TSA prevented pitting and crevice corrosion of 25% Cr SDSS in artificial seawater at 90 °C, even when 10-mm-diameter coating defect exposing the underlying steel was present.

Wave field features of shallow vertical discontinuity and their application in non-destructive detection

USGS Publications Warehouse

Liu, J.; Xia, J.; Luo, Y.; Chen, C.; Li, X.; Huang, Y.

2007-01-01

The geotechnical integrity of critical infrastructure can be seriously compromised by the presence of fractures or crevices. Non-destructive techniques to accurately detect fractures in critical infrastructure such as dams and highways could be of significant benefit to the geotechnical industry. This paper investigates the application of shallow seismic and georadar methods to the detection of a vertical discontinuity using numerical simulations. The objective is to address the kinematical analysis of a vertical discontinuity, determine the resulting wave field characteristics, and provide the basis for determining the existence of vertical discontinuities based on the recorded signals. Simulation results demonstrate that: (1) A reflection from a vertical discontinuity produces a hyperbolic feature on a seismic or georadar profile; (2) In order for a reflection from a vertical discontinuity to be produced, a reflecting horizon below the discontinuity must exist, the offset between source and receiver (x0) must be non-zero, on the same side of the vertical discontinuity; (3) The range of distances from the vertical discontinuity where a reflection event is observed is proportional to its length and to x0; (4) Should the vertical crevice (or fracture) pass through a reflecting horizon, dual hyperbolic features can be observed on the records, and this can be used as a determining factor that the vertical crevice passes through the interface; and (5) diffractions from the edges of the discontinuity can be recorded with relatively smaller amplitude than reflections and their ranges are not constrained by the length of discontinuity. If the length of discontinuity is short enough, diffractions are the dominant feature. Real-world examples show that the shallow seismic reflection method and the georadar method are capable of recording the hyperbolic feature, which can be interpreted as vertical discontinuity. Thus, these methods show some promise as effective non-destructive detection methods for locating vertical discontinuities (e.g., fractures or crevices) in infrastructure such as dams and highway pavement. ?? 2007 Elsevier B.V. All rights reserved.

The A-chain of insulin contacts the insert domain of the insulin receptor. Photo-cross-linking and mutagenesis of a diabetes-related crevice.

PubMed

Huang, Kun; Chan, Shu Jin; Hua, Qing-xin; Chu, Ying-Chi; Wang, Run-ying; Klaproth, Birgit; Jia, Wenhua; Whittaker, Jonathan; De Meyts, Pierre; Nakagawa, Satoe H; Steiner, Donald F; Katsoyannis, Panayotis G; Weiss, Michael A

2007-11-30

The contribution of the insulin A-chain to receptor binding is investigated by photo-cross-linking and nonstandard mutagenesis. Studies focus on the role of Val(A3), which projects within a crevice between the A- and B-chains. Engineered receptor alpha-subunits containing specific protease sites ("midi-receptors") are employed to map the site of photo-cross-linking by an analog containing a photoactivable A3 side chain (para-azido-Phe (Pap)). The probe cross-links to a C-terminal peptide (residues 703-719 of the receptor A isoform, KTFEDYLHNVVFVPRPS) containing side chains critical for hormone binding (underlined); the corresponding segment of the holoreceptor was shown previously to cross-link to a Pap(B25)-insulin analog. Because Pap is larger than Val and so may protrude beyond the A3-associated crevice, we investigated analogs containing A3 substitutions comparable in size to Val as follows: Thr, allo-Thr, and alpha-aminobutyric acid (Aba). Substitutions were introduced within an engineered monomer. Whereas previous studies of smaller substitutions (Gly(A3) and Ser(A3)) encountered nonlocal conformational perturbations, NMR structures of the present analogs are similar to wild-type insulin; the variant side chains are accommodated within a native-like crevice with minimal distortion. Receptor binding activities of Aba(A3) and allo-Thr(A3) analogs are reduced at least 10-fold; the activity of Thr(A3)-DKP-insulin is reduced 5-fold. The hormone-receptor interface is presumably destabilized either by a packing defect (Aba(A3)) or by altered polarity (allo-Thr(A3) and Thr(A3)). Our results provide evidence that Val(A3), a site of mutation causing diabetes mellitus, contacts the insert domain-derived tail of the alpha-subunit in a hormone-receptor complex.

Thermoregulatory challenges in the habitat of the world's smallest tortoise, Chersobius signatus.

PubMed

Loehr, Victor J T

2018-01-01

Ectotherms have various means of dealing with low environmental temperatures, but relatively few species have been rigorously investigated. Consequently, we have little information to predict how ectotherm populations might respond to global temperature changes. Tortoises from temperate and subtropical regions often overcome periodically cool conditions by hibernation, but speckled dwarf tortoises (Chersobius signatus) need to remain active to exploit ephemeral resources in their arid winter-rainfall habitat. This study investigated how dwarf tortoises cope with low temperatures in winter and spring, by measuring thermal habitat quality and thermoregulation based on differently-sized operative temperature models in sun, shade, and in deep crevices. Investigations continued in summer and autumn to obtain a year-round picture of thermoregulatory challenges. Although large models (i.e., larger than dwarf tortoises) were expected to have lower operative temperatures than smaller models, due to the former's larger thermal inertia, all model sizes had similar temperatures. Hence, the species' small body size does not appear constrained by obtainable body temperatures in cool seasons. Nevertheless, low operative temperatures in winter posed a challenge for the tortoises, which reached their field-preferred body temperature for an average of only 0.8-0.9h per day. Moreover, a low thermoregulation effectiveness suggested that tortoises traded-off physiological benefits of favourable body temperatures against predation risk. Spring and autumn provided higher temperatures, but summer caused the greatest thermoregulatory challenge. Although summer body temperatures were closer to field-preferred body temperature than in any other season, tortoises required rock crevices to avoid overheating. The small size of dwarf tortoises might help them utilise crevices. In summer, maximum operative temperatures in crevices were similar to field-preferred body temperature, indicating that an increase in environmental temperatures might be detrimental to dwarf tortoises. In light of projected temperature rises, future studies should assess if dwarf tortoises can cope with higher environmental temperatures in summer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Possibilities of fish passage through the block ramp: Model-based estimation of permeability.

PubMed

Plesiński, Karol; Bylak, Aneta; Radecki-Pawlik, Artur; Mikołajczyk, Tomasz; Kukuła, Krzysztof

2018-08-01

Block ramps offer an opportunity to combine hydrotechnical structures with fish passages. The primary study objective was to evaluate the effectiveness of a block ramp for upstream fish movement in a mountain stream. Geodetic measurements of the bottom surface and water level were taken for three cross-sections. The description of the geometric and hydrodynamic parameters of the block ramp was supplemented with information on the width and length of crevices between boulders. Measurements of the geometric and hydrodynamic parameters of the block ramp were performed at 76 measurement sites, at three different types of discharge. Ichthyological data were collected in the analyzed stream. Measurements covered among others total length, width, and height of caught fish. Salmonid, cottid, balitorid, and cyprinid fish were studied. The determination of the main effects of the geometric and hydrodynamic parameters of the block ramp on the possibilities of use by target fish species employed generalized linear models (GLMs). The study shows that the block ramp cannot provide longitudinal connectivity and migration of fish occurring in the mountain stream. According to estimates, the block ramp did not meet the permeability expectations. The reason for low usefulness of the ramp for fish is particularly excessively strong water current. The stream concentration constituted an unsurmountable velocity barrier for fish moving upstream for each of the analyzed discharges. The developed model suggests that some crevices in the side zones of the ramp could be parts of the migration corridor, but only for small and medium-sized fish. At medium and high water stages, movement of fish in crevices was difficult due to fast water current, and at low and very low discharges, some crevices lost their permeability, and could become ecological traps for fish. The necessity of estimation of ramp permeability during pre-construction phase was emphasized. Copyright © 2018 Elsevier B.V. All rights reserved.

Corrosion Performance of Inconel 625 in High Sulphate Content

NASA Astrophysics Data System (ADS)

Ismail, Azzura

2016-05-01

Inconel 625 (UNS N06625) is a type of nickel-chromium-molybdenum alloy with excellent corrosion resistance in a wide range of corrosive media, being especially resistant to pitting and crevice corrosion. However, in aggressive environment, Inconel 625 will suffer corrosion attack like other metals. This research compared the corrosion performance of Inconel 625 when exposed to higher sulphate content compared to real seawater. The results reveal that Inconel 625 is excellent in resist the corrosion attack in seawater. However, at increasing temperature, the corrosion resistance of this metal decrease. The performance is same in seawater with high sulphate content at increasing temperature. It can be concluded that sulphate promote perforation on Inconel 625 and become aggressive agents that accelerate the corrosion attack.

Production of intergranular attack of alloy 600, alloy 690, and alloy 800 tubing in tubesheet crevices: Topical report

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

Scott, D.B.; Glaves, C.L.,

1987-07-01

Three model boilers, manufactured to simulate full-size tube sheet crevices, were tested with various secondary side environments. The first was faulted with organics representative of the decomposition of humic acid. The second was faulted with sodium carbonate and sodium hydroxide, while the third was faulted with sodium sulfate and sodium hydroxide. Each model contained seven tubes, which included Alloy 600 in the mill-annealed (MA) and thermally-treated (TT) conditions and Alloy 690 in the thermally-treated condition. Two models contained Alloy 800 tubes in the mill-annealed condition and one had Alloy 800 in the mill-annealed/cold-worked/glass-bead-peened condition. Two different sizes of tubesheet crevicesmore » were used in all model boilers. In the organics-faulted boiler, tubes of Alloy 600MA, Alloy 690TT and Alloy 800MA experienced no significant intergranular attack (IGA); however, the Alloy 600TT had intergranular attack (IGA) three to four grains deep. The carbonate-caustic faulted boiler experienced throughwall stress corrosion cracking (SCC) in all tubes of Alloy 600 MA and Alloy 800 MA. Eddy current indications were present in Alloy 690TT, Alloy 600TT and Alloy 800 in the mill-annealed/cold worked/glass-bead-peened condition. Metallographic examination of tubes from the third model boiler, faulted with sodium sulfate and caustic, revealed IGA in the mill-annealed Alloy 600 tubes. The IGA was more extensive in an Alloy 600 tube annealed at 1700/sup 0/F than an Alloy 600 tube annealed at 1875/sup 0/F.« less

Analysis of in vivo corrosion of 316L stainless steel posterior thoracolumbar plate systems: a retrieval study.

PubMed

Majid, Kamran; Crowder, Terence; Baker, Erin; Baker, Kevin; Koueiter, Denise; Shields, Edward; Herkowitz, Harry N

2011-12-01

One hundred eighteen patients retrieved 316L stainless steel thoracolumbar plates, of 3 different designs, used for fusion in 60 patients were examined for evidence of corrosion. A medical record review and statistical analysis were also carried out. This study aims to identify types of corrosion and examine preferential metal ion release and the possibility of statistical correlation to clinical effects. Earlier studies have found that stainless steel spine devices showed evidence of mild-to-severe corrosion; fretting and crevice corrosion were the most commonly reported types. Studies have also shown the toxicity of metal ions released from stainless steel corrosion and how the ions may adversely affect bone formation and/or induce granulomatous foreign body responses. The retrieved plates were visually inspected and graded based on the degree of corrosion. The plates were then analyzed with optical microscopy, scanning electron microscopy, and energy dispersive x-ray spectroscopy. A retrospective medical record review was performed and statistical analysis was carried out to determine any correlations between experimental findings and patient data. More than 70% of the plates exhibited some degree of corrosion. Both fretting and crevice corrosion mechanisms were observed, primarily at the screw plate interface. Energy dispersive x-ray spectroscopy analysis indicated reductions in nickel content in corroded areas, suggestive of nickel ion release to the surrounding biological environment. The incidence and severity of corrosion was significantly correlated with the design of the implant. Stainless steel thoracolumbar plates show a high incidence of corrosion, with statistical dependence on device design.

Structure of the Minor Pseudopilin EpsH From the Type 2 Secretion System of Vibrio Cholerae

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

Yanez, M.E.; Korotkov, K.V.; Abendroth, J.

2009-05-28

Many Gram-negative bacteria use the multi-protein type II secretion system (T2SS) to selectively translocate virulence factors from the periplasmic space into the extracellular environment. In Vibrio cholerae the T2SS is called the extracellular protein secretion (Eps) system, which translocates cholera toxin and several enzymes in their folded state across the outer membrane. Five proteins of the T2SS, the pseudopilins, are thought to assemble into a pseudopilus, which may control the outer membrane pore EpsD, and participate in the active export of proteins in a 'piston-like' manner. We report here the 2.0 {angstrom} resolution crystal structure of an N-terminally truncated variantmore » of EpsH, a minor pseudopilin from Vibrio cholerae. While EpsH maintains an N-terminal {alpha}-helix and C-terminal {beta}-sheet consistent with the type 4a pilin fold, structural comparisons reveal major differences between the minor pseudopilin EpsH and the major pseudopilin GspG from Klebsiella oxytoca: EpsH contains a large {beta}-sheet in the variable domain, where GspG contains an {alpha}-helix. Most importantly, EpsH contains at its surface a hydrophobic crevice between its variable and conserved {beta}-sheets, wherein a majority of the conserved residues within the EpsH family are clustered. In a tentative model of a T2SS pseudopilus with EpsH at its tip, the conserved crevice faces away from the helix axis. This conserved surface region may be critical for interacting with other proteins from the T2SS machinery.« less

A new finding on the in-vivo crevice corrosion damage in a CoCrMo hip implant.

PubMed

Oskouei, Reza H; Barati, Mohammad Reza; Farhoudi, Hamidreza; Taylor, Mark; Solomon, Lucian Bogdan

2017-10-01

A detailed investigation was performed to characterize the fretting wear and corrosion damage to the neck component of a CoCrMo stem from a metal-on-polyethylene implant retrieved after 99months. The stem was a low-carbon (0.07wt%) wrought Co-28Cr-6Mo alloy with no secondary carbide phases in the matrix (γ-phase). The original design of the neck surface contained an intentionally fabricated knurled profile with a valley-to-peak range of approximately 11μm. Roughness measurements indicated that the tip of the knurled profile was significantly damaged, especially in the distal medial region of the neck, with up to a 22% reduction in the mean peak-to-valley height (R a ) compared to the original profile. As a new finding, the channels between the peaks of the profile created an additional crevice site in the presence of stagnant body fluid within the head-neck taper junction. These channels were observed to contain the most severe corroded areas and surface oxide layers with micro-cracks. SEM/EDS, XRD and XPS evaluations identified the formation of Cr 2 O 3 as a corrosion product. Also, decobaltification was found to occur in these corroded areas. The findings of this work indicate the important role of the knurled profile in inducing additional crevice corrosion. Copyright © 2017 Elsevier B.V. All rights reserved.

Performance of (UNS 8028) production tubing material in sour service environment of Khuff gas formation

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

Al-Maslamani, M.

Khuff gas formation is one of the largest reservoirs of non-associated gas in the world. Recent developments in exploration and production from Khuff gas formation at the Qatar North Field required materials of construction with long periods of production without work over and chemical inhibition. Gas produced contains corrosive constituents such as 1% H{sub 2}S, 4% CO{sub 2} and brine at pressures exceeding 300 barg (CITHP). For operational reasons, two of the 16 wells drilled were needed to work over after 2 years of service and showed evidence of crevice pitting corrosion and thread galling on the Corrosion Resistance Alloymore » (CRA) tubing material. Full inspection and analysis of the problem are addressed in this paper.« less

40 CFR 144.3 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... facility” Improved sinkhole means a naturally occurring karst depression or other natural crevice found in... the Administrator under the “appropriate Act and regulations.” Major facility means any UIC “facility...

In situ nano- to microscopic imaging and growth mechanism of electrochemical dissolution (e.g., corrosion) of a confined metal surface

PubMed Central

Merola, C.; Cheng, H.-W.; Schwenzfeier, K.; Kristiansen, K.; Chen, Y.-J.; Dobbs, H. A.; Valtiner, M.

2017-01-01

Reactivity in confinement is central to a wide range of applications and systems, yet it is notoriously difficult to probe reactions in confined spaces in real time. Using a modified electrochemical surface forces apparatus (EC-SFA) on confined metallic surfaces, we observe in situ nano- to microscale dissolution and pit formation (qualitatively similar to previous observation on nonmetallic surfaces, e.g., silica) in well-defined geometries in environments relevant to corrosion processes. We follow “crevice corrosion” processes in real time in different pH-neutral NaCl solutions and applied surface potentials of nickel (vs. Ag|AgCl electrode in solution) for the mica–nickel confined interface of total area ∼0.03 mm2. The initial corrosion proceeds as self-catalyzed pitting, visualized by the sudden appearance of circular pits with uniform diameters of 6–7 μm and depth ∼2–3 nm. At concentrations above 10 mM NaCl, pitting is initiated at the outer rim of the confined zone, while below 10 mM NaCl, pitting is initiated inside the confined zone. We compare statistical analysis of growth kinetics and shape evolution of individual nanoscale deep pits with estimates from macroscopic experiments to study initial pit growth and propagation. Our data and experimental techniques reveal a mechanism that suggests initial corrosion results in formation of an aggressive interfacial electrolyte that rapidly accelerates pitting, similar to crack initiation and propagation within the confined area. These results support a general mechanism for nanoscale material degradation and dissolution (e.g., crevice corrosion) of polycrystalline nonnoble metals, alloys, and inorganic materials within confined interfaces. PMID:28827338

Mapping the membrane-aqueous border for the voltage-sensing domain of a potassium channel.

PubMed

Neale, Edward J; Rong, Honglin; Cockcroft, Christopher J; Sivaprasadarao, Asipu

2007-12-28

Voltage-sensing domains (VSDs) play diverse roles in biology. As integral components, they can detect changes in the membrane potential of a cell and couple these changes to activity of ion channels and enzymes. As independent proteins, homologues of the VSD can function as voltage-dependent proton channels. To sense voltage changes, the positively charged fourth transmembrane segment, S4, must move across the energetically unfavorable hydrophobic core of the bilayer, which presents a barrier to movement of both charged species and protons. To reduce the barrier to S4 movement, it has been suggested that aqueous crevices may penetrate the protein, reducing the extent of total movement. To investigate this hypothesis in a system containing fully functional channels in a native environment with an intact membrane potential, we have determined the contour of the membrane-aqueous border of the VSD of KvAP in Escherichia coli by examining the chemical accessibility of introduced cysteines. The results revealed the contour of the membrane-aqueous border of the VSD in its activated conformation. The water-inaccessible regions of S1 and S2 correspond to the standard width of the membrane bilayer (~28 A), but those of S3 and S4 are considerably shorter (> or = 40%), consistent with aqueous crevices pervading both the extracellular and intracellular ends. One face of S3b and the entire S3a were water-accessible, reducing the water-inaccessible region of S3 to just 10 residues, significantly shorter than for S4. The results suggest a key role for S3 in reducing the distance S4 needs to move to elicit gating.

Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

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

Charlot, L.A.; Westerman, R.E.

A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allowsmore » its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.« less

How Dangerous Can Localized Corrosion Be? An Experiment that Studies Its Effects.

ERIC Educational Resources Information Center

Celdran, R.; Gonzalo, P.

1988-01-01

Considers three common cases of localized corrosion of metals: pitting, crevice, and stress corrosion. Provides experimental methods for studying all three methods. Includes a discussion of expected results. (ML)

FINAL ANALYTICAL RESULTS FROM THE EXAMINATION OF CORROSION ON SECTIONS OF CORROSION PROBE REMOVED FROM TANK 241-AN-107 ON 08/10/2006

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

DUNCAN JB; COOKE GA

2007-03-22

Tank Farms Operations removed an electrochemical noise probe from Tank 241-AN-107. In the field, the probe was cut into four sections, wrapped, and placed in a 55-gallon drum, This drum was delivered to the 222-S Laboratory. The 222 S Laboratory unpackaged the sections of the AN-107 electrochemical noise probe and examined the material for evidence of corrosion. Each of the four sections contained three C-ring and three bullet specimens. The specimens were examined for pitting corrosion, crevice corrosion, and stress corrosion cracking. No evidence of stress corrosion cracking was found in the stressed C-ring specimens. Minor pitting was evident onmore » some surfaces. Crevice corrosion was the dominant type of corrosion observed.« less

Colony mapping: A new technique for monitoring crevice-nesting seabirds

USGS Publications Warehouse

Renner, H.M.; Renner, M.; Reynolds, J.H.; Harping, A.M.A.; Jones, I.L.; Irons, D.B.; Byrd, G.V.

2006-01-01

Monitoring populations of auklets and other crevice-nesting seabirds remains problematic, although numerous methods have been attempted since the mid-1960s. Anecdotal evidence suggests several large auklet colonies have recently decreased in both abundance and extent, concurrently with vegetation encroachment and succession. Quantifying changes in the geographical extent of auklet colonies may be a useful alternative to monitoring population size directly. We propose a standardized method for colony mapping using a randomized systematic grid survey with two components: a simple presence/absence survey and an auklet evidence density survey. A quantitative auklet evidence density index was derived from the frequency of droppings and feathers. This new method was used to map the colony on St. George Island in the southeastern Bering Sea and results were compared to previous colony mapping efforts. Auklet presence was detected in 62 of 201 grid cells (each grid cell = 2500 m2) by sampling a randomly placed 16 m2 plot in each cell; estimated colony area = 155 000 m2. The auklet evidence density index varied by two orders of magnitude across the colony and was strongly correlated with means of replicated counts of birds socializing on the colony surface. Quantitatively mapping all large auklet colonies is logistically feasible using this method and would provide an important baseline for monitoring colony status. Regularly monitoring select colonies using this method may be the best means of detecting changes in distribution and population size of crevice-nesting seabirds. ?? The Cooper Ornithological Society 2006.

Corrosion behavior of 2205 duplex stainless steel.

PubMed

Platt, J A; Guzman, A; Zuccari, A; Thornburg, D W; Rhodes, B F; Oshida, Y; Moore, B K

1997-07-01

The corrosion of 2205 duplex stainless steel was compared with that of AISI type 316L stainless steel. The 2205 stainless steel is a potential orthodontic bracket material with low nickel content (4 to 6 wt%), whereas the 316L stainless steel (nickel content: 10 to 14 wt%) is a currently used bracket material. Both stainless steels were subjected to electrochemical and immersion (crevice) corrosion tests in 37 degrees C, 0.9 wt% sodium chloride solution. Electrochemical testing indicates that 2205 has a longer passivation range than 316L. The corrosion rate of 2205 was 0.416 MPY (milli-inch per year), whereas 316L exhibited 0.647 MPY. When 2205 was coupled to 316L with equal surface area ratio, the corrosion rate of 2205 reduced to 0.260 MPY, indicating that 316L stainless steel behaved like a sacrificial anode. When 316L is coupled with NiTi, TMA, or stainless steel arch wire and was subjected to the immersion corrosion test, it was found that 316L suffered from crevice corrosion. On the other hand, 2205 stainless steel did not show any localized crevice corrosion, although the surface of 2205 was covered with corrosion products, formed when coupled to NiTi and stainless steel wires. This study indicates that considering corrosion resistance, 2205 duplex stainless steel is an improved alternative to 316L for orthodontic bracket fabrication when used in conjunction with titanium, its alloys, or stainless steel arch wires.

40 CFR 180.513 - Chlorfenapyr; tolerances for residues.

Code of Federal Regulations, 2011 CFR

2011-07-01

... greater than a 0.5% active ingredient solution for spot crack and crevice use in food/feed handling.... Application excludes any direct application to any food, food packaging, or any food contact surfaces. (v) To...

Tandem mobile robot system

DOEpatents

Buttz, James H.; Shirey, David L.; Hayward, David R.

2003-01-01

A robotic vehicle system for terrain navigation mobility provides a way to climb stairs, cross crevices, and navigate across difficult terrain by coupling two or more mobile robots with a coupling device and controlling the robots cooperatively in tandem.

Maintenance of human adipose derived stem cell (hASC) differentiation capabilities using a 3D culture.

PubMed

Lin, Ching-Yu; Huang, Chi-Hui; Wu, Yuan-Kun; Cheng, Nai-Chen; Yu, Jiashing

2014-07-01

In this study, 3D culture system for human adipose-derived stem cell (hASC) using a BioLevitator as the bioreactor for microcarrier-based cultures was established. During the culturing period, hASCs preferred to grow in crevices between microcarriers and a high viability was maintained even when reaching confluency. Adipogenic or osteogenic differential medium was used to induce hASCs and differential potentials of these cells were compared between 2D and 3D environments via RT-PCR and staining quantifications. CEBP/α gene expression was significant higher in 3D condition at day 21 (P < 0.05). Staining quantification indicates that cells cultured in 3D condition have significant better differentiation potential from day 14 to 21 for both adipogenic and osteogenic lineages (P < 0.01).

33 CFR 159.121 - Sewage processing test.

Code of Federal Regulations, 2010 CFR

2010-07-01

... crevices that could come in contact with a person using the device or servicing the device in accordance..., the device must be tilted to the maximum angles specified by the manufacturer under §§ 159.55 and 159...

Friction enhancement in concertina locomotion of snakes

PubMed Central

Marvi, Hamidreza; Hu, David L.

2012-01-01

Narrow crevices are challenging terrain for most organisms and biomimetic robots. Snakes move through crevices using sequential folding and unfolding of their bodies in the manner of an accordion or concertina. In this combined experimental and theoretical investigation, we elucidate this effective means of moving through channels. We measure the frictional properties of corn snakes, their body kinematics and the transverse forces they apply to channels of varying width and inclination. To climb channels inclined at 60°, we find snakes use a combination of ingenious friction-enhancing techniques, including digging their ventral scales to double their frictional coefficient and pushing channel walls transversely with up to nine times body weight. Theoretical modelling of a one-dimensional n-linked crawler is used to calculate the transverse force factor of safety: we find snakes push up to four times more than required to prevent sliding backwards, presumably trading metabolic energy for an assurance of wall stability. PMID:22728386

Corrosion of simulated bearing components of three bearing steels in the presence of chloride-contaminated lubricant

NASA Technical Reports Server (NTRS)

Parker, R. J.; Bamberger, E. N.; Nahm, A. H.

1983-01-01

Corrosion tests were run with AISI 52100, AISI M-50 and AMS 5794 under conditions that simulate the crevice corrosion found in aircraft ball and roller bearings rejected at overhaul for corrosion. Test specimens were fabricated that simulated the contacts of balls or rollers and the raceways. Corrosion cells were assembled in the presence of a lubricant contaminated with water and chloride ions. The cell was then thermally cycled between 339 K (150 F) and 276 K (37 F). The corrosion observed after 14 cycles was that of crevice and pitting corrosion typically found in aircraft bearings. AMS 5749 showed a very slight amount of corrosion. No appreciable differences were noted between AISI 52100 and AISI M-50, but both showed much greater corrosion than AMS 5749. The corrosion pits observed in AISI M-50 appeared to be fewer in number but generally deeper and larger than in AISI 52100.

Friction enhancement in concertina locomotion of snakes.

PubMed

Marvi, Hamidreza; Hu, David L

2012-11-07

Narrow crevices are challenging terrain for most organisms and biomimetic robots. Snakes move through crevices using sequential folding and unfolding of their bodies in the manner of an accordion or concertina. In this combined experimental and theoretical investigation, we elucidate this effective means of moving through channels. We measure the frictional properties of corn snakes, their body kinematics and the transverse forces they apply to channels of varying width and inclination. To climb channels inclined at 60°, we find snakes use a combination of ingenious friction-enhancing techniques, including digging their ventral scales to double their frictional coefficient and pushing channel walls transversely with up to nine times body weight. Theoretical modelling of a one-dimensional n-linked crawler is used to calculate the transverse force factor of safety: we find snakes push up to four times more than required to prevent sliding backwards, presumably trading metabolic energy for an assurance of wall stability.

Halogen-Enriched Fragment Libraries as Leads for Drug Rescue of Mutant p53

PubMed Central

2012-01-01

The destabilizing p53 cancer mutation Y220C creates a druggable surface crevice. We developed a strategy exploiting halogen bonding for lead discovery to stabilize the mutant with small molecules. We designed halogen-enriched fragment libraries (HEFLibs) as starting points to complement classical approaches. From screening of HEFLibs and subsequent structure-guided design, we developed substituted 2-(aminomethyl)-4-ethynyl-6-iodophenols as p53-Y220C stabilizers. Crystal structures of their complexes highlight two key features: (i) a central scaffold with a robust binding mode anchored by halogen bonding of an iodine with a main-chain carbonyl and (ii) an acetylene linker, enabling the targeting of an additional subsite in the crevice. The best binders showed induction of apoptosis in a human cancer cell line with homozygous Y220C mutation. Our structural and biophysical data suggest a more widespread applicability of HEFLibs in drug discovery. PMID:22439615

Rail assembly for use in a radioactive environment

DOEpatents

Watts, Ralph E.

1989-01-01

An improved rail assembly and method of construction thereof is disclosed herein that is particularly adapted for use with a crane trolley in a hot cell environment which is exposed to airborne and liquidborne radioactive contaminants. The rail assembly is generally comprised of a support wall having an elongated, rail-housing recess having a floor, side wall and ceiling. The floor of the recess is defined at least in part by the load-bearing surface of a rail, and is substantially flat, level and crevice-free to facilitate the drainage of liquids out of the recess. The ceiling of the recess overhangs and thereby captures trolley wheels within the recess to prevent them from becoming dislodged from the recess during a seismic disturbance. Finally, the interior of the recess includes a power track having a slot for receiving a sliding electrical connector from the crane trolley. The power track is mounted in an upper corner of the recess with its connector-receiving groove oriented downwardly to facilitate the drainage of liquidborne contaminants and to discourage the collection of airborne contaminants within the track.

Physiological Intracellular Crowdedness is Defined by the Perimeter-to-Area Ratio of Sub-Cellular Compartments

PubMed Central

Hiroi, Noriko; Okuhara, Takahiro; Kubojima, Takeshi; Iba, Keisuke; Tabira, Akito; Yamashita, Shuji; Okada, Yasunori; Kobayashi, Tetsuya J.; Funahashi, Akira

2012-01-01

The intracellular environment is known to be a crowded and inhomogeneous space. Such an in vivo environment differs from a well-diluted, homogeneous environment for biochemical reactions. However, the effects of both crowdedness and the inhomogeneity of environment on the behavior of a mobile particle have not yet been investigated sufficiently. As described in this paper, we constructed artificial reaction spaces with fractal models, which are assumed to be non-reactive solid obstacles in a reaction space with crevices that function as operating ranges for mobile particles threading the space. Because of the homogeneity of the structures of artificial reaction spaces, the models succeeded in reproducing the physiological fractal dimension of solid structures with a smaller number of non-reactive obstacles than in the physiological condition. This incomplete compatibility was mitigated when we chose a suitable condition of a perimeter-to-area ratio of the operating range to our model. Our results also show that a simulation space is partitioned into convenient reaction compartments as an in vivo environment with the exact amount of solid structures estimated from TEM images. The characteristics of these compartments engender larger mean square displacement of a mobile particle than that of particles in smaller compartments. Subsequently, the particles start to show confined particle-like behavior. These results are compatible with our previously presented results, which predicted that a physiological environment would produce quick response and slow exhaustion reactions. PMID:22936917

Application of ANS fluorescent probes to identify hydrophobic sites on the surface of DREAM.

PubMed

Gonzalez, Walter G; Miksovska, Jaroslava

2014-09-01

DREAM (calsenilin or KChIP-3) is a calcium sensor involved in regulation of diverse physiological processes by interactions with multiple intracellular partners including DNA, Kv4 channels, and presenilin, however the detailed mechanism of the recognition of the intracellular partners remains unclear. To identify the surface hydrophobic surfaces on apo and Ca(2+)DREAM as a possible interaction sites for target proteins and/or specific regulators of DREAM function the binding interactions of 1,8-ANS and 2,6-ANS with DREAM were characterized by fluorescence and docking studies. Emission intensity of ANS-DREAM complexes increases upon Ca(2+) association which is consistent with an overall decrease in surface polarity. The dissociation constants for ANS binding to apoDREAM and Ca(2+)DREAM were determined to be 195±20μM and 62±4μM, respectively. Fluorescence lifetime measurements indicate that two ANS molecules bind in two independent binding sites on DREAM monomer. One site is near the exiting helix of EF-4 and the second site is located in the hydrophobic crevice between EF-3 and EF-4. 1,8-ANS displacement studies using arachidonic acid demonstrate that the hydrophobic crevice between EF-3 and EF-4 serves as a binding site for fatty acids that modulate functional properties of Kv4 channel:KChIP complexes. Thus, the C-terminal hydrophobic crevice may be involved in DREAM interactions with small hydrophobic ligands as well as other intracellular proteins. Copyright © 2014 Elsevier B.V. All rights reserved.

Potentiodynamic polarization study of the in vitro corrosion behavior of 3 high-palladium alloys and a gold-palladium alloy in 5 media.

PubMed

Sun, Desheng; Monaghan, Peter; Brantley, William A; Johnston, William M

2002-01-01

Corrosion of cast alloy restorations may lead to their failure or adversely affect their biocompatibility. Although some documentation of the corrosion behavior of the high-palladium dental alloys exists, questions remain about their corrosion resistance and mechanisms. This study compared the in vitro corrosion characteristics of 3 high-palladium alloys and 1 gold-palladium alloy in simulated body fluid and oral environments. Two Pd-Cu-Ga alloys and 1 Pd-Ga alloy were selected; an Au-Pd alloy served as the control. The corrosion behavior for the as-cast and simulated porcelain-firing (heat-treated) conditions of each alloy (N = 5) was evaluated in 0.9% NaCl, 0.09% NaCl, and Fusayama solutions. Heat-treated specimens of each alloy (N = 5) were also tested in N(2)-deaerated 0.09% NaCl and Fusayama solutions (pH 4). After immersion in the electrolyte for 24 hours, the open-circuit potential (OCP) was measured, and linear polarization was performed from -20 mV to +20 mV (vs. OCP) at a scanning rate of 0.125 mV/s. Cyclic polarization was performed from -300 mV to +1000 mV and back to -300 mV (vs. OCP) at a scanning rate of 1 mV/s. Data were evaluated with analysis of variance and the Ryan-Einot-Gabriel-Welsch multiple-range test (alpha=.05). The OCP of each alloy varied with the condition (as-cast or heat-treated) and electrolyte used. Corrosion resistance was similar for the 4 alloys tested. For cyclic polarization, all alloys showed active-passive or spontaneous passive behavior in nearly all electrolytes. During some reverse scans, the 3 high-palladium alloys displayed 3 or 5 anodic peaks. No positive hysteresis was observed for any of the alloy/electrolyte combinations evaluated. The corrosion resistances of the 3 high-palladium alloys in simulated body fluid and oral environments were comparable to that of the gold-palladium alloy. The similar corrosion resistance for the 3 high-palladium alloys was attributed to their high noble metal content and theorized stable structure at the submicron level. Selective corrosion of different phases and elements, surface enrichment of palladium, and adsorption of species are possible corrosion mechanisms. The cyclic polarization results suggest that none of the 4 alloys would be prone to pitting or crevice corrosion under in vivo conditions, but crevice conditions should nonetheless be avoided for these alloys in the oral environment.

Investigation of passive films on nickel Alloy 690 in lead-containing environments

NASA Astrophysics Data System (ADS)

Peng, B.; Lu, B. T.; Luo, J. L.; Lu, Y. C.; Ma, H. Y.

2008-09-01

Passive films formed on Alloy UNS N06690 were investigated in simulated crevice chemistries. It was found the role of lead in corrosion processes is strongly dependent on the pH value of the testing solutions. At pH 1.5 the effect of lead is narrowly noticeable; while at pH 12.7, lead has a significant influence on the electrochemical performance of alloy UNS N06690. The lead alters the surface morphologies at both pH and account for higher hydroxide content in the surface film at pH 12.7. The lead incorporation hinders the formation of spinel oxides during the passivation in alkaline solution. Nanoindentation tests indicate a significant lead-induced degradation in the mechanical properties of passive films. The passivation degradation is attributed to detrimental effects of lead via interrupting the dehydration process and hindering the formation of protective layers on the alloy surface.

Full immersion simulation: validation of a distributed simulation environment for technical and non-technical skills training in Urology.

PubMed

Brewin, James; Tang, Jessica; Dasgupta, Prokar; Khan, Muhammad S; Ahmed, Kamran; Bello, Fernando; Kneebone, Roger; Jaye, Peter

2015-07-01

To evaluate the face, content and construct validity of the distributed simulation (DS) environment for technical and non-technical skills training in endourology. To evaluate the educational impact of DS for urology training. DS offers a portable, low-cost simulated operating room environment that can be set up in any open space. A prospective mixed methods design using established validation methodology was conducted in this simulated environment with 10 experienced and 10 trainee urologists. All participants performed a simulated prostate resection in the DS environment. Outcome measures included surveys to evaluate the DS, as well as comparative analyses of experienced and trainee urologist's performance using real-time and 'blinded' video analysis and validated performance metrics. Non-parametric statistical methods were used to compare differences between groups. The DS environment demonstrated face, content and construct validity for both non-technical and technical skills. Kirkpatrick level 1 evidence for the educational impact of the DS environment was shown. Further studies are needed to evaluate the effect of simulated operating room training on real operating room performance. This study has shown the validity of the DS environment for non-technical, as well as technical skills training. DS-based simulation appears to be a valuable addition to traditional classroom-based simulation training. © 2014 The Authors BJU International © 2014 BJU International Published by John Wiley & Sons Ltd.

MOVEMENT AND DEPOSITION OF PESTICIDES WITHIN RESIDENCES AFTER INTERIOR AND EXTERIOR APPLICATIONS

EPA Science Inventory

In a study begun in 1999, the Environmental Protection Agency (EPA) investigated the temporal and spatial distributions of pesticides applied by homeowners and commercial applicators for indoor crack and crevice and exterior perimeter treatments. In each participating househol...

Effects of Corrosion and Fatigue on the Load-Carrying Capacity of Structural and Reinforcing Steel

DOT National Transportation Integrated Search

1994-03-01

Pitting and crevice corrosion have profound effects on the fatigue life of structural and reinforcing steels used in bridge construction. Stress concentration factors were measured on actual corroded plates with strain gage instrumentation. Using cor...

Inhibition of dog and human gastric lipases by enantiomeric phosphonate inhibitors: a structure-activity study.

PubMed

Miled, Nabil; Roussel, Alain; Bussetta, Cécile; Berti-Dupuis, Liliane; Rivière, Mireille; Buono, Gérard; Verger, Robert; Cambillau, Christian; Canaan, Stéphane

2003-10-14

The crystal structures of gastric lipases in the apo form [Roussel, A., et al. (1999) J. Biol. Chem. 274, 16995-17002] or in complex with the (R(P))-undecyl butyl phosphonate [C(11)Y(4)(+)] [Roussel, A., et al. (2002) J. Biol. Chem. 277, 2266-2274] have improved our understanding of the structure-activity relationships of acid lipases. In this report, we have performed a kinetic study with dog and human gastric lipases (DGL and HGL, respectively) using several phosphonate inhibitors by varying the absolute configuration of the phosphorus atom and the chain length of the alkyl/alkoxy substituents. Using the two previously determined structures and that of a new crystal structure obtained with the other (S(P))-phosphonate enantiomer [C(11)Y(4)(-)], we constructed models of phosphonate inhibitors fitting into the active site crevices of DGL and HGL. All inhibitors with a chain length of fewer than 12 carbon atoms were found to be completely buried in the catalytic crevice, whereas longer alkyl/alkoxy chains were found to point out of the cavity. The main stereospecific determinant explaining the stronger inhibition of the S(P) enantiomers is the presence of a hydrogen bond involving the catalytic histidine as found in the DGL-C(11)Y(4)(-) complex. On the basis of these results, we have built a model of the first tetrahedral intermediate corresponding to the tristearoyl-lipase complex. The triglyceride molecule completely fills the active site crevice of DGL, in contrast with what is observed with other lipases such as pancreatic lipases which have a shallower and narrower active site. For substrate hydrolysis, the supply of water molecules to the active site might be achieved through a lateral channel identified in the protein core.

General and crevice corrosion study of the in-wall shielding materials for ITER vacuum vessel

NASA Astrophysics Data System (ADS)

Joshi, K. S.; Pathak, H. A.; Dayal, R. K.; Bafna, V. K.; Kimihiro, Ioki; Barabash, V.

2012-11-01

Vacuum vessel In-Wall Shield (IWS) will be inserted between the inner and outer shells of the ITER vacuum vessel. The behaviour of IWS in the vacuum vessel especially concerning the susceptibility to crevice of shielding block assemblies could cause rapid and extensive corrosion attacks. Even galvanic corrosion may be due to different metals in same electrolyte. IWS blocks are not accessible until life of the machine after closing of vacuum vessel. Hence, it is necessary to study the susceptibility of IWS materials to general corrosion and crevice corrosion under operations of ITER vacuum vessel. Corrosion properties of IWS materials were studied by using (i) Immersion technique and (ii) Electro-chemical Polarization techniques. All the sample materials were subjected to a series of examinations before and after immersion test, like Loss/Gain weight measurement, SEM analysis, and Optical stereo microscopy, measurement of surface profile and hardness of materials. After immersion test, SS 304B4 and SS 304B7 showed slight weight gain which indicate oxide layer formation on the surface of coupons. The SS 430 material showed negligible weight loss which indicates mild general corrosion effect. On visual observation with SEM and Metallography, all material showed pitting corrosion attack. All sample materials were subjected to series of measurements like Open Circuit potential, Cyclic polarization, Pitting potential, protection potential, Critical anodic current and SEM examination. All materials show pitting loop in OC2 operating condition. However, its absence in OC1 operating condition clearly indicates the activity of chloride ion to penetrate oxide layer on the sample surface, at higher temperature. The critical pitting temperature of all samples remains between 100° and 200°C.

40 CFR 180.530 - 2,2-Dimethyl-1,3-benzodioxol-4-ol methylcarbamate; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... used in spot and/or crack and crevice treatments in animal feed handling establishments, including feed... insecticide 2,2-dimethyl-1,3-benzodioxol-4-yl methylcarbamate may be safely used in spot and/or crack and...

Elastomer-induced crevice corrosion and stress corrosion cracking of stainless steel heat exchanger plates in sour amine service

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

Hay, M.G.; Baron, J.J.; Moffat, T.A.

1996-08-01

Types S31600 and S31254 stainless steel heat exchanger plates have suffered crevice corrosion and stress corrosion cracking under gaskets in rich amine service in a sour gas plant. The gasket material, ethylene-propylene-diene monomer (EPDM), has been used successfully for many years at other sour gas plants. Laboratory testing has duplicated the corrosion observed and shown that the mechanism is synergistic sulfide-halide attack. The use of a bromine plus chlorine-activated curing system for the EPDM rubber gaskets provided the necessary halides. Laboratory testing identified some nickel-based superalloys which were resistant to this corrosion and also demonstrated that essentially halogen-free, peroxide-cured EPDMmore » gaskets do not cause attack of S31600 or S31254. The heat exchanger packs were replaced with S31600 plates and peroxide-cured EPDM gaskets having a specified total halogen concentration of 200 ppm maximum. Field operating experience has been excellent.« less

Applying Uncertainty Analysis to a Risk Assessment for the Pesticide Permethrin

EPA Science Inventory

We discuss the application of methods of uncertainty analysis from our previous poster to the problem of a risk assessment for exposure to the food-use pesticide permethrin resulting from residential pesticide crack and crevice application. Exposures are simulated by the SHEDS (S...

Using airborne laser altimetry to estimate Sabellaria alveolata (Polychaeta: Sabellariidae) reefs volume in tidal flat environments

NASA Astrophysics Data System (ADS)

Noernberg, Mauricio Almeida; Fournier, Jérôme; Dubois, Stanislas; Populus, Jacques

2010-12-01

This study has exploited aerial photographs and LiDAR digital elevation model to quantify intertidal complex landforms volume. A first volume estimation of the main sabellariid polychaete reef complex of the Bay of Mont-Saint-Michel - France is presented. The Sabellaria alveolata is an engineering species that heavily modifies its environment. This gregarious tube-building annelid forms dense and solid reefs of bioclastic coarse sand which can reach several km 2. Since 1970 a very strong decline of reefs has been observed. The authorities have curbed fishing activities without any noticeable changes in reef health status. The S. alveolata reef volume is estimated to be 132 048 m 3 (96 301 m 3 for Sainte-Anne reef and 35 747 m 3 for Champeaux reef). Further LiDAR data surveys will be needed to be able to understand and quantify the accretion/erosion processes in play in the reef dynamic. Because of the internal variability of topographic complexity of the reef, characterized by crevices, cracks, and holes rather than whole blocks, further studies are needed to calculate more accurately the volume of the reef.

Corrosion inhibition of steam generator tubesheet by Alloy 690 cladding in secondary side environments

NASA Astrophysics Data System (ADS)

Hur, Do Haeng; Choi, Myung Sik; Lee, Deok Hyun; Han, Jung Ho; Shim, Hee Sang

2013-11-01

Denting is a phenomenon that a steam generator tube is distorted by a volume expansion of corrosion products of the tube support and tubesheet materials adjacent to the tube. Although denting has been mitigated by a modification of the design and material of the tube support structures, it has been an inevitable concern in the crevice region of the top of tubesheet. This paper provides a new technology to prevent denting by cladding the secondary surface of the tubesheet with a corrosion resistant material. In this study, Alloy 690 material was cladded onto the surface of an SA508 tubesheet to a thickness of about 9 mm. The corrosion rates of the original SA508 tubesheet and the Alloy 690 clad material were measured in acidic and alkaline simulated environments. Using Alloy 690 cladding, the corrosion rate of the tubesheet within a magnetite sludge pile decreased by a factor of 680 in 0.1 M NiCl2 solution at 300 °C, and by a factor of 58 in 2 M NaOH solution at 315 °C. This means that denting can drastically be prevented by cladding the secondary tubesheet surface with corrosion resistant materials.

76 FR 31471 - Ethylene Glycol; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-01

... production (NAICS code 112). Food manufacturing (NAICS code 311). Pesticide manufacturing (NAICS code 32532..., submitted a petition to EPA under the Federal Food, Drug, and Cosmetic Act (FFDCA), requesting an... residual, and crack and crevice sprays in and around food and nonfood areas of residential and...

Nonequilibrium Synthesis of Highly Porous Single-Crystalline Oxide Nanostructures

DOE PAGES

Lee, Dongkyu; Gao, Xiang; Fan, Lisha; ...

2017-01-20

A novel synthesis route to the formation of vertically aligned single–crystalline oxide nanostructures is found by precisely controlling the nonequilibrium pulsed laser deposition process. Here, the columnar nanostructures with deep crevices offering a large surface area are generated owing to the diffusion limited geometric shadowing effect.

Simulation fails to replicate stress in trainees performing a technical procedure in the clinical environment.

PubMed

Baker, B G; Bhalla, A; Doleman, B; Yarnold, E; Simons, S; Lund, J N; Williams, J P

2017-01-01

Simulation-based training (SBT) has become an increasingly important method by which doctors learn. Stress has an impact upon learning, performance, technical, and non-technical skills. However, there are currently no studies that compare stress in the clinical and simulated environment. We aimed to compare objective (heart rate variability, HRV) and subjective (state trait anxiety inventory, STAI) measures of stress theatre with a simulated environment. HRV recordings were obtained from eight anesthetic trainees performing an uncomplicated rapid sequence induction at pre-determined procedural steps using a wireless Polar RS800CX monitor © in an emergency theatre setting. This was repeated in the simulated environment. Participants completed an STAI before and after the procedure. Eight trainees completed the study. The theatre environment caused an increase in objective stress vs baseline (p = .004). There was no significant difference between average objective stress levels across all time points (p = .20) between environments. However, there was a significant interaction between the variables of objective stress and environment (p = .045). There was no significant difference in subjective stress (p = .27) between environments. Simulation was unable to accurately replicate the stress of the technical procedure. This is the first study that compares the stress during SBT with the theatre environment and has implications for the assessment of simulated environments for use in examinations, rating of technical and non-technical skills, and stress management training.

NASA Space Environments Technical Discipline Team Space Weather Activities

NASA Astrophysics Data System (ADS)

Minow, J. I.; Nicholas, A. C.; Parker, L. N.; Xapsos, M.; Walker, P. W.; Stauffer, C.

2017-12-01

The Space Environment Technical Discipline Team (TDT) is a technical organization led by NASA's Technical Fellow for Space Environments that supports NASA's Office of the Chief Engineer through the NASA Engineering and Safety Center. The Space Environments TDT conducts independent technical assessments related to the space environment and space weather impacts on spacecraft for NASA programs and provides technical expertise to NASA management and programs where required. This presentation will highlight the status of applied space weather activities within the Space Environment TDT that support development of operational space weather applications and a better understanding of the impacts of space weather on space systems. We will first discuss a tool that has been developed for evaluating space weather launch constraints that are used to protect launch vehicles from hazardous space weather. We then describe an effort to better characterize three-dimensional radiation transport for CubeSat spacecraft and processing of micro-dosimeter data from the International Space Station which the team plans to make available to the space science community. Finally, we will conclude with a quick description of an effort to maintain access to the real-time solar wind data provided by the Advanced Composition Explorer satellite at the Sun-Earth L1 point.

83. Photographic copy of historic photo, December 16, 1929 (original ...

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

83. Photographic copy of historic photo, December 16, 1929 (original print filed in Record Group 115, National Archives, Washington, D.C.). OWYHEE DAM-LOOKING DOWNSTREAM FROM UPPER COFFERDAM (POINT #15) SHOWING CREVICE AND KEYWAY CUTOFF; ALSO CABLEWAY CONTROL HOUSE AND ENTRANCE ADIT. - Owyhee Dam, Across Owyhee River, Nyssa, Malheur County, OR

THE DISTRIBUTION OF CHLORPYRIFOS FOLLOWING A CRACK AND CREVICE TYPE APPLICAITON IN THE U.S. EPA INDOOR AIR QUALITY (IAQ) TEST HOUSE

EPA Science Inventory

Pesticides found in homes may result from indoor applications to control household pests or by translocation from outdoor sources. Pesticides disperse according to their physical properties and other factors such as human activity, residential air exchange, temperature and humi...

THE SPATIAL AND TEMPORAL DISTRIBUTION OF CHLORPYRIFOS IN THE U.S. EPA INDOOR AIR QUALITY (IAQ) TEST HOUSE FOLLOWING CRACK AND CREVICE TYPE APPLICATIONS

EPA Science Inventory

Pesticides found in homes may result from indoor applications to control household pests or by translocation from outdoor sources. Pesticides disperse according to their physical properties and other factors such as human activity, air exchange, temperature and humidity. Insect...

Effect of temperature on the passivation behavior of steel rebar

NASA Astrophysics Data System (ADS)

Chen, Shan-meng; Cao, Bei; Wu, Yin-shun; Ma, Ke

2014-05-01

Steel rebar normally forms an oxide or rusty skin before it is embedded into concrete and the passivation properties of this skin will be heavily influenced by temperature. To study the effect of temperature on the passivation properties of steel rebar under different surface conditions, we conducted scanning electron microscopy (SEM) observations and electrochemical measurements, such as measurements of the free corrosion potential and polarization curves of HPB235 steel rebar. These measurements identified three kinds of surfaces: polished, oxide skin, and rusty skin. Our results show that the passivation properties of all the surface types decrease with the increase of temperature. Temperature has the greatest effect on the rusty-skin rebar and least effect on the polished steel rebar, because of cracks and crevices on the mill scale on the steel rebar's surface. The rusty-skin rebar exhibits the highest corrosion rate because crevice corrosion can accelerate the corrosion of the steel rebar, particularly at high temperature. The results also indicate that the threshold temperatures of passivation for the oxide-skin rebar and the rusty-skin rebar are 37°C and 20°C, respectively.

Effect of pH on Structural Changes in Perch Hemoglobin that Can Alter Redox Stability and Heme Affinity

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

Richards, Mark P.; Aranda, IV, Roman; He, Cai

2010-01-07

pH can be manipulated to alter the oxidative stability of fish-based foods during storage. X-ray diffraction was used to investigate the ability of reduced pH to cause structural changes in fish hemoglobins that lead to enhanced oxidative degradation. Decreasing pH from 8.0 to 6.3 and 5.7 created a large channel for solvent entry into the heme crevice of perch hemoglobin beta chains. The proton-induced opening of this channel occurred between site CD3 and the heme-6-propionate. Solvent entry into the heme crevice can enhance metHb formation and hemin loss, processes that accelerate lipid oxidation. Reduced pH also decreased the distance betweenmore » Ile at E11 in one of the alpha chains and the ligand above the heme iron atom. This sterically displaces O{sub 2} and protonated O{sub 2} which increases metHb formation. These studies demonstrate that pH reduction causes structural changes in perch hemoglobin which increase oxidative degradation of the heme pigment.« less

Electrostatic field of the large fragment of Escherichia coli DNA polymerase I.

PubMed

Warwicker, J; Ollis, D; Richards, F M; Steitz, T A

1985-12-05

The electrostatic field of the large fragment of Escherichia coli DNA polymerase I (Klenow fragment) has been calculated by the finite difference procedure on a 2 A grid. The potential field is substantially negative at physiological pH (reflecting the net negative charge at this pH). The largest regions of positive potential are in the deep crevice of the C-terminal domain, which is the proposed binding site for the DNA substrate. Within the crevice, the electrostatic potential has a partly helical form. If the DNA is positioned to fulfil stereochemical requirements, then the positive potential generally follows the major groove and (to a lesser extent) the negative potential is in the minor groove. Such an arrangement could stabilize DNA configurations related by screw symmetry. The histidine residues of the Klenow fragment give the positive field of the groove a sensitivity to relatively small pH changes around neutrality. We suggest that the histidine residues could change their ionization states in response to DNA binding, and that this effect could contribute to the protein-DNA binding energy.

Electrochemical Testing of Ni-Cr-Mo-Gd Alloys

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

T. E. Lister; R. E. Mizia; H. Tian

2005-10-01

The waste package site recommendation design specified a boron-containing stainless steel, Neutronit 976/978, for fabrication of the internal baskets that will be used as a corrosion-resistant neutron-absorbing material. Recent corrosion test results gave higher-than-expected corrosion rates for this material. The material callout for these components has been changed to a Ni-Cr-Mo-Gd alloy (ASTM-B 932-04, UNS N06464) that is being developed at the Idaho National Laboratory. This report discusses the results of initial corrosion testing of this material in simulated in-package environments that could contact the fuel baskets after breach of the waste package outer barrier. The corrosion test matrix wasmore » executed using the potentiodynamic and potentiostatic electrochemical test techniques. The alloy performance shows low rates of general corrosion after initial removal of a gadolinium-rich second phase that intersects the surface. The high halide-containing test solutions exhibited greater tendencies toward initiation of crevice corrosion.« less

Classification of acoustic emission signals using wavelets and Random Forests : Application to localized corrosion

NASA Astrophysics Data System (ADS)

Morizet, N.; Godin, N.; Tang, J.; Maillet, E.; Fregonese, M.; Normand, B.

2016-03-01

This paper aims to propose a novel approach to classify acoustic emission (AE) signals deriving from corrosion experiments, even if embedded into a noisy environment. To validate this new methodology, synthetic data are first used throughout an in-depth analysis, comparing Random Forests (RF) to the k-Nearest Neighbor (k-NN) algorithm. Moreover, a new evaluation tool called the alter-class matrix (ACM) is introduced to simulate different degrees of uncertainty on labeled data for supervised classification. Then, tests on real cases involving noise and crevice corrosion are conducted, by preprocessing the waveforms including wavelet denoising and extracting a rich set of features as input of the RF algorithm. To this end, a software called RF-CAM has been developed. Results show that this approach is very efficient on ground truth data and is also very promising on real data, especially for its reliability, performance and speed, which are serious criteria for the chemical industry.

Durable bonds at the adhesive/dentin interface: an impossible mission or simply a moving target?

PubMed Central

SPENCER, Paulette; Jonggu PARK, Qiang YE; MISRA, Anil; BOHATY, Brenda S.; SINGH, Viraj; PARTHASARATHY, Ranga; SENE, Fábio; de Paiva GONÇALVES, Sérgio Eduardo; LAURENCE, Jennifer

2013-01-01

Composite restorations have higher failure rates, more recurrent caries and increased frequency of replacement as compared to dental amalgam. Penetration of bacterial enzymes, oral fluids, and bacteria into the crevices between the tooth and composite undermines the restoration and leads to recurrent decay and failure. The gingival margin of composite restora tions is particularly vulnerable to decay and at this margin, the adhesive and its seal to dentin provides the primary barrier between the prepared tooth and the environment. The intent of this article is to examine physico-chemical factors that affect the integrity and durability of the adhesive/dentin interfacial bond; and to explore how these factors act synergistically with mechanical forces to undermine the composite restoration. The article will examine the various avenues that have been pursued to address these problems and it will explore how alterations in material chemistry could address the detrimental impact of physico-chemical stresses on the bond formed at the adhesive/dentin interface. PMID:24855586

Dynamics of the His79-heme alkaline transition of yeast iso-1-cytochrome c probed by conformationally gated electron transfer with Co(II)bis(terpyridine).

PubMed

Cherney, Melisa M; Junior, Carolyn C; Bergquist, Bryan B; Bowler, Bruce E

2013-08-28

Alkaline conformers of cytochrome c may be involved in both its electron transport and apoptotic functions. We use cobalt(II)bis(terpyridine), Co(terpy)2(2+), as a reagent for conformationally gated electron-transfer (gated ET) experiments to study the alkaline conformational transition of K79H variants of yeast iso-1-cytochrome c expressed in Escherichia coli , WT*K79H, with alanine at position 72 and Saccharomyces cerevisiae , yK79H, with trimethyllysine (Tml) at position 72. Co(terpy)2(2+) is well-suited to the 100 ms to 1 s time scale of the His79-mediated alkaline conformational transition of these variants. Reduction of the His79-heme alkaline conformer by Co(terpy)2(2+) occurs primarily by gated ET, which involves conversion to the native state followed by reduction, with a small fraction of the His79-heme alkaline conformer directly reduced by Co(terpy)2(2+). The gated ET experiments show that the mechanism of formation of the His79-heme alkaline conformer involves only two ionizable groups. In previous work, we showed that the mechanism of the His73-mediated alkaline conformational transition requires three ionizable groups. Thus, the mechanism of heme crevice opening depends upon the position of the ligand mediating the process. The microscopic rate constants provided by gated ET studies show that mutation of Tml72 (yK79H variant) in the heme crevice loop to Ala72 (WT*K79H variant) affects the dynamics of heme crevice opening through a small destabilization of both the native conformer and the transition state relative to the His79-heme alkaline conformer. Previous pH jump data had indicated that the Tml72→Ala mutation primarily stabilized the transition state for the His79-mediated alkaline conformational transition.

Enhancement of juvenile Caribbean spiny lobsters: an evaluation of changes in multiple response variables with the addition of large artificial shelters.

PubMed

Briones-Fourzán, Patricia; Lozano-Alvarez, Enrique; Negrete-Soto, Fernando; Barradas-Ortiz, Cecilia

2007-03-01

Shortage of natural crevice shelters may produce population bottlenecks in juvenile Caribbean spiny lobsters (Panulirus argus), a socially gregarious species. We conducted a field experiment to test enhancement of a local population of juvenile P. argus with the addition of artificial shelters ("casitas") that mimic large crevices (1.1 m(2) in surface area and 3.8 cm in height). Changes in density and biomass of juvenile lobsters 15-50 mm carapace length (CL) were assessed with a multiple before-after control-impact (MBACI) analysis. Separate analyses were also conducted on small (15-35 mm CL) and large (35.1-50 mm CL) juveniles to assess size-related effects. First, we carried out 13 lobster surveys on nine fixed 1-ha sites over a shallow reef lagoon ("before" period). Then, we deployed ten casitas in each of five sites and left four sites as controls, and conducted 22 further surveys ("after" period). Deployment of casitas resulted in a sixfold increase in juvenile density (76% contributed by small and 24% by large juveniles) and a sevenfold increase in biomass (40 and 60%, respectively). Capture-recapture results revealed that enhancement was achieved not by promoting individual growth but by increasing survival, persistence, and foraging ranges of small and large juveniles. Casitas both mitigated shortage of natural shelter and increased sociality, allowing for cohabitation of smaller, more vulnerable juveniles with larger conspecifics that have greater defensive abilities. Casitas may help enhance local populations of juvenile P. argus in Caribbean seagrass habitats, typically poor in natural crevice shelters. The use of MBACI and the simultaneous assessment of multiple interrelated response variables may be a powerful analytical approach to test shelter limitation in other species and to examine the function of structural habitat in other systems.

Structure–function characterization of three human antibodies targeting the vaccinia virus adhesion molecule D8

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

Matho, Michael H.; Schlossman, Andrew; Gilchuk, Iuliia M.

Vaccinia virus (VACV) envelope protein D8 is one of three glycosaminoglycan adhesion molecules and binds to the linear polysaccharide chondroitin sulfate (CS). D8 is also a target for neutralizing antibody responses that are elicited by the smallpox vaccine, which has enabled the first eradication of a human viral pathogen and is a useful model for studying antibody responses. However, to date, VACV epitopes targeted by human antibodies have not been characterized at atomic resolution. Here in this paper, we characterized the binding properties of several human anti-D8 antibodies and determined the crystal structures of three VACV-mAb variants, VACV-66, VACV-138, andmore » VACV-304, separately bound to D8. Although all these antibodies bound D8 with high affinity and were moderately neutralizing in the presence of complement, VACV-138 and VACV-304 also fully blocked D8 binding to CS-A, the low affinity ligand for D8. VACV-138 also abrogated D8 binding to the high-affinity ligand CS-E, but we observed residual CS-E binding was observed in the presence of VACV-304. Analysis of the VACV-138– and VACV-304–binding sites along the CS-binding crevice of D8, combined with different efficiencies of blocking D8 adhesion to CS-A and CS-E allowed us to propose that D8 has a high- and low-affinity CS-binding region within its central crevice. The crevice is amenable to protein engineering to further enhance both specificity and affinity of binding to CS-E. Finally, a wild-type D8 tetramer specifically bound to structures within the developing glomeruli of the kidney, which express CS-E. We propose that through structure-based protein engineering, an improved D8 tetramer could be used as a potential diagnostic tool to detect expression of CS-E, which is a possible biomarker for ovarian cancer.« less

Structure–function characterization of three human antibodies targeting the vaccinia virus adhesion molecule D8

DOE PAGES

Matho, Michael H.; Schlossman, Andrew; Gilchuk, Iuliia M.; ...

2017-11-09

Vaccinia virus (VACV) envelope protein D8 is one of three glycosaminoglycan adhesion molecules and binds to the linear polysaccharide chondroitin sulfate (CS). D8 is also a target for neutralizing antibody responses that are elicited by the smallpox vaccine, which has enabled the first eradication of a human viral pathogen and is a useful model for studying antibody responses. However, to date, VACV epitopes targeted by human antibodies have not been characterized at atomic resolution. Here in this paper, we characterized the binding properties of several human anti-D8 antibodies and determined the crystal structures of three VACV-mAb variants, VACV-66, VACV-138, andmore » VACV-304, separately bound to D8. Although all these antibodies bound D8 with high affinity and were moderately neutralizing in the presence of complement, VACV-138 and VACV-304 also fully blocked D8 binding to CS-A, the low affinity ligand for D8. VACV-138 also abrogated D8 binding to the high-affinity ligand CS-E, but we observed residual CS-E binding was observed in the presence of VACV-304. Analysis of the VACV-138– and VACV-304–binding sites along the CS-binding crevice of D8, combined with different efficiencies of blocking D8 adhesion to CS-A and CS-E allowed us to propose that D8 has a high- and low-affinity CS-binding region within its central crevice. The crevice is amenable to protein engineering to further enhance both specificity and affinity of binding to CS-E. Finally, a wild-type D8 tetramer specifically bound to structures within the developing glomeruli of the kidney, which express CS-E. We propose that through structure-based protein engineering, an improved D8 tetramer could be used as a potential diagnostic tool to detect expression of CS-E, which is a possible biomarker for ovarian cancer.« less

Dynamics of the His79-heme Alkaline Transition of Yeast Iso-1-cytochrome c Probed by Conformationally-gated Electron Transfer with Co(II)bis(terpyridine)†

PubMed Central

Cherney, Melisa M.; Junior, Carolyn C.; Bergquist, Bryan B.; Bowler, Bruce E.

2013-01-01

Alkaline conformers of cytochrome c may be involved in both its electron transport and apoptotic functions. We use cobalt(II)bis(terpyridine), Co(terpy)22+, as a reagent for conformationally-gated electron transfer (gated ET) experiments to study the alkaline conformational transition of K79H variants of yeast iso-1-cytochrome c expressed in Escherichia coli, WT*K79H, with alanine at position 72, and Saccharomyces cerevisiae, yK79H, with trimethyllysine (Tml) at position 72. Co(terpy)22+ is well-suited to the 100 ms to 1 s time scale of the His79-mediated alkaline conformational transition of these variants. Reduction of the His79-heme alkaline conformer by Co(terpy)22+ occurs primarily by gated ET, which involves conversion to the native state followed by reduction, with a small fraction of the His79- heme alkaline conformer directly reduced by Co(terpy)22+. The gated ET experiments show that the mechanism of formation of the His79-heme alkaline conformer involves only two ionizable groups. In previous work, we showed that the mechanism of the His73-mediated alkaline conformational transition requires three ionizable groups. Thus, the mechanism of heme crevice opening depends upon the position of the ligand mediating the process. The microscopic rate constants provided by gated ET studies show that mutation of Tml72 (yK79H variant) in the heme crevice loop to Ala72 (WT*K79H variant) affects the dynamics of heme crevice opening through a small destabilization of both the native conformer and the transition state relative to the His79-heme alkaline conformer. Previous pH jump data had indicated that the Tml72→Ala mutation primarily stabilized the transition state for the His79-mediated alkaline conformational transition. PMID:23899348

Interspecific Competition for Shelters in Territorial and Gregarious Intertidal Grazers: Consequences for Individual Behaviour

PubMed Central

Aguilera, Moisés A.; Navarrete, Sergio A.

2012-01-01

Experiments have shown that interspecific interactions within consumer guilds can alter patterns of distribution, abundance and size of species. Plastic behavioural responses can be modulated by agonistic interactions. In many cases, consumers compete for space and shelters, and these interactions change the manner in which they exploit food. This study investigates the consequences of competition in the spatial and temporal organization of behaviour of intertidal grazers, which share algal resources and the use of rock crevices while resting, but exhibit different body sizes, spatial behaviour and foraging modes. We evaluate interaction strength between small gregarious Siphonaria lessoni and the larger territorial keyhole limpet Fissurella crassa and between S. lessoni and the medium-size gregarious chiton Chiton granosus. Using field manipulations and artificial arenas in the laboratory, we tested whether the use of crevices, micro-spatial distribution and activity are modified by the density of conspecifics and the presence of heterospecifics. Our results show that small-scale spatial segregation observed in the field between S. lessoni and C. granosus result from species-specific differences in habitat use. In turn, we found evidence that spatial segregation between F. crassa and S. lessoni results from highly asymmetric interference competition in the use of shelters. The presence of F. crassa reduced the use of crevices and growth rates of S. lessoni. Effects on growth rates are assumed to result from exposure to harsh environmental conditions rather than food limitation. Thus, neither gregarious behaviour nor differences in activity were sufficient to prevent competition with the larger grazer. Our study illustrates the importance of competition for shelters, which results in behavioural changes of the smaller-sized species, and how these plastic responses can translate into differences in growth rates. Use of shelters can thus be modulated by environmental conditions in a species-specific as well as an interactive manner within consumers’ guilds. PMID:23049980

Lightning Protection Guidelines for Aerospace Vehicles

NASA Technical Reports Server (NTRS)

Goodloe, C. C.

1999-01-01

This technical memorandum provides lightning protection engineering guidelines and technical procedures used by the George C. Marshall Space Flight Center (MSFC) Electromagnetics and Aerospace Environments Branch for aerospace vehicles. The overviews illustrate the technical support available to project managers, chief engineers, and design engineers to ensure that aerospace vehicles managed by MSFC are adequately protected from direct and indirect effects of lightning. Generic descriptions of the lightning environment and vehicle protection technical processes are presented. More specific aerospace vehicle requirements for lightning protection design, performance, and interface characteristics are available upon request to the MSFC Electromagnetics and Aerospace Environments Branch, mail code EL23.

Biology of bats in Douglas-fir forests.

Treesearch

Robin E. Christy; Stephen D. West

1993-01-01

Twelve species of bats occur in Douglas-fir forests of the Pacific Northwest, of which nine are known to roost in tree cavities, bark crevices, or foliage, and several are closely associated with old-growth forests. Thus bat populations may be detrimentally affected by forest management practices involving the removal of large, old trees and snags. We review the life...

Working the Crevices: Granting Students Authority in Authoritarian Schools

ERIC Educational Resources Information Center

Goodman, Joan F.; Hoagland, Jessica; Pierre-Toussaint, Nadel; Rodriguez, Celeste; Sanabria, Christina

2011-01-01

Schools are beset with a serious "alienation gap" between teachers and students that is no less a problem than the "achievement gap." Increasing student voice is thought to be one means to fill the gap, for it activates agency and thereby decreases passivity. The extent of agency ranges from attentive adult listening to strong student leadership.…

40 CFR 52.744 - Small business stationary source technical and environmental compliance assistance program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Small business stationary source technical and environmental compliance assistance program. 52.744 Section 52.744 Protection of Environment... PLANS Illinois> § 52.744 Small business stationary source technical and environmental compliance...

40 CFR 52.798 - Small business stationary source technical and environmental compliance assistance program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Small business stationary source technical and environmental compliance assistance program. 52.798 Section 52.798 Protection of Environment... PLANS Indiana § 52.798 Small business stationary source technical and environmental compliance...

40 CFR Appendix A to Part 67 - Technical Support Document

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Technical Support Document A Appendix A to Part 67 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...—Technical Support Document Note: EPA will make copies of appendix A available from: Director, Stationary...

40 CFR Appendix A to Part 66 - Technical Support Document

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Technical Support Document A Appendix A to Part 66 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...—Technical Support Document Note: For text of appendix A see appendix A to part 67. ...

Introducing Heuristics of Cultural Dimensions into the Service-Level Technical Communication Classroom

ERIC Educational Resources Information Center

Schafer, Robert

2009-01-01

A significant problem for practitioners of technical communication is to gain the skills to compete in a global, multicultural work environment. Instructors of technical communication can provide future practitioners with the tools to compete and excel in this global environment by introducing heuristics of cultural dimensions into the…

Status of ash (Fraxinus spp.) species in Alabama, Arkansas, Mississippi, and Louisiana, 2013

Treesearch

S.N. Oswalt

2015-01-01

The emerald ash borer (EAB; Agrilus planipennis) is an introduced Asian beetle species that was first detected in trees in the Fraxinus (ash) genus in the United States in 2002. Female EAB beetles lay between 40 to 70 eggs in cracks, crevices, and beneath bark flakes. The eggs hatch within about 2 weeks, larvae bore through the...

ATLAS 60’ Fording Study

DTIC Science & Technology

1992-03-03

crack. Carbon steel stress cracks in the presence of sodium hydroxide (" caustic embrittlement"), whereas austenitic stainless steels stress crack in...transmission life. - Outboard planetary axle design reduces stresses on differential, drive shafts and axle shaft U-joints. . Enclosed oil disc brakes on... Stress Corrosion Crevice Pitting Erosion Corrosion Uniform Corrosion Intergranular Selective Leaching Page 19 Caterpflar Inc. ATLAS Fording Study Q The

Office of Naval Research Overview of Corrosion S&T Program

DTIC Science & Technology

2010-12-02

a carbon induced passivity for LTCSS treated austenitic stainless steels - Low temp. allows interstitial C diffusion, but not substitutional...paraequilibrium carburization mechanism(s) that lead to the enhanced corrosion resistance seaw ater crevice corrosion on 316 Stainless Steel LTC...Treated 316 untreated LTC process TTT diagram LTCSS Surface Modification: • Carbon concentrations > 12 at. % in 316 stainless steel while maintaining

Structural variability and species diversity of a dwarf Caribbean dry forest

Treesearch

E. Medina; E. Cuevas; S. Molina; A.E. Lugo; O. Ramos

2010-01-01

Low stature woody vegetation of the south-west coast of Puerto Rico grows on a rocky calcareous substrate where plants can only root in holes, cracks, and crevices accumulating water and sediments that allow seed germination and seedling development. Being in a coastal location these communities are influenced by steady onshore winds, high solar radiation, and salt...

Coordinated vigilance provides evidence for direct reciprocity in coral reef fishes.

PubMed

Brandl, Simon J; Bellwood, David R

2015-09-25

Reciprocity is frequently assumed to require complex cognitive abilities. Therefore, it has been argued that reciprocity may be restricted to animals that can meet these demands. Here, we provide evidence for the potential presence of direct reciprocity in teleost fishes. We demonstrate that in pairs of coral reef rabbitfishes (f. Siganidae), one fish frequently assumes an upright vigilance position in the water column, while the partner forages in small crevices in the reef substratum. Both behaviours are strongly coordinated and partners regularly alternate their positions, resulting in a balanced distribution of foraging activity. Compared to solitary individuals, fishes in pairs exhibit longer vigilance bouts, suggesting that the help provided to the partner is costly. In turn, fishes in pairs take more consecutive bites and penetrate deeper into crevices than solitary individuals, suggesting that the safety provided by a vigilant partner may outweigh initial costs by increasing foraging efficiency. Thus, the described system appears to meet all of the requirements for direct reciprocity. We argue that the nature of rabbitfish pairs provides favourable conditions for the establishment of direct reciprocity, as continuous interaction with the same partner, simultaneous needs, interdependence, and communication relax the cognitive demands of reciprocal cooperation.

Using Aerogel-Based Insulation Material To Prevent Foam Loss on the Liquid-Hydrogen Intertank

NASA Technical Reports Server (NTRS)

2008-01-01

Uninsulated areas on cryogenic propellant tanks and feedlines cause moisture in the air to condense or ice to form. Flange joints, bracket supports, expansion bellows, and other cavities are uninsulated by design. These areas cannot be sealed because conventional thermal insulation materials would restrict mechanical articulations. Aerogel-based thermal insulation systems are able to seal critical locations such as the liquid-oxygen (LO2) feedline bellows. A new thermal insulation system was also necessary between the intertank wall, flange, and the liquid-hydrogen (LH2) tank dome, where there is a cavity (or crevice) with an exposed 20-K surface. When nitrogen gas is used for purging within the intertank volume, it condenses on this cold surface. Some solid nitrogen may also form on the colder side of the crevice. Voids or discontinuities within the foam can pressurize and cause areas of foam to weaken and break off, reducing thermal efficiency and creating potentially dangerous debris. To prevent this foam loss, we developed a thermal insulation system using bulk-fill aerogel material and demonstrated it with a one-tenth-scale model of the LH2 intertank flange area

Experimental tooth pain elevates substance P and matrix metalloproteinase-8 levels in human gingival crevice fluid.

PubMed

Avellán, Nina-Li; Sorsa, Timo; Tervahartiala, Taina; Forster, Clemens; Kemppainen, Pentti

2008-02-01

Tooth pain can induce a neurogenic inflammatory reaction in gingiva in association with local elevations of matrix metalloproteinase (MMP)-8, which is considered the major tissue destructive protease in gingival crevice fluid (GCF). The pro-inflammatory neuropeptides released by sensory nerves coordinate the activities of the immuno-effector cells and may influence the secretion of MMP-8. With this background, we studied whether experimental tooth pain can trigger changes in GCF levels of the neuropeptide substance P (SP) and MMP-8. The GCF SP levels of stimulated and non-stimulated teeth were analyzed for SP using a competitive enzyme immunoassay (EIA). The GCF MMP-8 levels were determined by quantitative immunofluorometric assay (IFMA). Painful stimulation of the upper central incisor caused significant elevations in GCF SP and MMP-8 levels of the stimulated tooth. At the same time, the GCF SP and MMP-8 levels of non-stimulated control teeth were unchanged. These data indicate that experimental tooth pain can induce local elevations of SP and MMP-8 levels in GCF simultaneously. This supports the possibility of a local neurogenic spread of inflammatory reactions from intrapulpal to surrounding periodontal tissues.

Orbital debris: A technical assessment

NASA Technical Reports Server (NTRS)

Gleghorn, George; Asay, James; Atkinson, Dale; Flury, Walter; Johnson, Nicholas; Kessler, Donald; Knowles, Stephen; Rex, Dietrich; Toda, Susumu; Veniaminov, Stanislav

1995-01-01

To acquire an unbiased technical assessment of (1) the research needed to better understand the debris environment, (2) the necessity and means of protecting spacecraft against the debris environment, and (3) potential methods of reducing the future debris hazard, NASA asked the National Research Council to form an international committee to examine the orbital debris issue. The committee was asked to draw upon available data and analyses to: characterize the current debris environment, project how this environment might change in the absence of new measures to alleviate debris proliferation, examine ongoing alleviation activities, explore measures to address the problem, and develop recommendations on technical methods to address the problems of debris proliferation.

Facilitating 3D Virtual World Learning Environments Creation by Non-Technical End Users through Template-Based Virtual World Instantiation

ERIC Educational Resources Information Center

Liu, Chang; Zhong, Ying; Ozercan, Sertac; Zhu, Qing

2013-01-01

This paper presents a template-based solution to overcome technical barriers non-technical computer end users face when developing functional learning environments in three-dimensional virtual worlds (3DVW). "iVirtualWorld," a prototype of a platform-independent 3DVW creation tool that implements the proposed solution, facilitates 3DVW…

Identifying Effective Strategies to Providing Technical Support to One-to-One Programs

ERIC Educational Resources Information Center

Thomas, Mark W.

2013-01-01

The problem of this study was that while one-to-one initiatives in the K-12 environment are growing, the technical support personnel that work in these environments are experiencing problems supporting these initiatives. The purposes of this study were to: (a) identify common problems of providing technical support in a one-to-one laptop program,…

40 CFR 35.4185 - What does my group do with reports our technical advisor prepares for us?

Code of Federal Regulations, 2013 CFR

2013-07-01

... Assistance Managing Your Tag § 35.4185 What does my group do with reports our technical advisor prepares for... 40 Protection of Environment 1 2013-07-01 2013-07-01 false What does my group do with reports our technical advisor prepares for us? 35.4185 Section 35.4185 Protection of Environment ENVIRONMENTAL...

40 CFR 35.4185 - What does my group do with reports our technical advisor prepares for us?

Code of Federal Regulations, 2012 CFR

2012-07-01

... Assistance Managing Your Tag § 35.4185 What does my group do with reports our technical advisor prepares for... 40 Protection of Environment 1 2012-07-01 2012-07-01 false What does my group do with reports our technical advisor prepares for us? 35.4185 Section 35.4185 Protection of Environment ENVIRONMENTAL...

40 CFR 35.4185 - What does my group do with reports our technical advisor prepares for us?

Code of Federal Regulations, 2011 CFR

2011-07-01

... Assistance Managing Your Tag § 35.4185 What does my group do with reports our technical advisor prepares for... 40 Protection of Environment 1 2011-07-01 2011-07-01 false What does my group do with reports our technical advisor prepares for us? 35.4185 Section 35.4185 Protection of Environment ENVIRONMENTAL...

40 CFR 35.4185 - What does my group do with reports our technical advisor prepares for us?

Code of Federal Regulations, 2014 CFR

2014-07-01

... Assistance Managing Your Tag § 35.4185 What does my group do with reports our technical advisor prepares for... 40 Protection of Environment 1 2014-07-01 2014-07-01 false What does my group do with reports our technical advisor prepares for us? 35.4185 Section 35.4185 Protection of Environment ENVIRONMENTAL...

Developing Technical Expertise in Secondary Technical Schools: The Effect of 4C/ID Learning Environments

ERIC Educational Resources Information Center

Sarfo, Frederick K.; Elen, Jan

2007-01-01

In this study, the effectiveness of learning environments, developed in line with the specifications of the four components instructional design model (4C/ID model) and the additional effect of ICT for fostering the development of technical expertise in traditional Ghanaian classrooms, was assessed. The study had a one-by-one-by-two…

Planar multi-electrode array sensor for localized electrochemical corrosion detection

DOEpatents

Tormoen, Garth William; Brossia, Christopher Sean

2014-01-07

A planarized type of coupled multi-electrode corrosion sensing device. Electrode pads are fabricated on a thin backing, such as a thin film. Each pad has an associated electrical lead for connection to auxiliary electronic circuitry, which may include a resistor associated with each electrical pad. The design permits the device to be easily placed in small crevices or under coatings such as paint.

Corrosion Fatigue

DTIC Science & Technology

1981-10-01

particularly under conditions of cathodic polarization. Sul- fate ion , while less damaging under free corrosion conditions, is equally aggressive at...Editing and Reproduction Ltd Harford 11ouse, 7-9 Charlotte St, London, WIP 1HD I I - PREFACE Failure by fatigue and degradation by corrosion continue to...of halide ions . In the unstressed state, this degrada- tion may be manifested by localized corrosion such as pitting, crevice corrosion or ex

Multi-Scale Investigation of the Formation and Breakdown of Passive Films on Carbon Steel Rebar in Concrete

NASA Astrophysics Data System (ADS)

Ghods, Pouria

The multi-scale investigation presented in this thesis was carried out to understand better the mechanisms of passivation and chloride-induced depassivation of carbon steel reinforcement in concrete. The study consisted of electrochemical experiments (electrochemical impedance spectroscopy, linear polarization resistance, free corrosion potential, anodic polarization), microscopic examinations (scanning electron microscopy, transmission electron microscopy, selected area diffraction, convergent beam electron diffraction), numerical modeling (finite element method), and spectroscopic studies (x-ray photoelectron, energy dispersed x-ray, electron energy loss). Electrochemical and microscopic studies showed that the composition of the pore solution and the surface conditions of the rebar affect the passivity and depassivation of carbon steel in concrete. It was demonstrated that crevices between mill scale and steel may become potential sites for depassivation and pit nucleation. The numerical investigation that was carried out to test this hypothesis confirmed that the ratio of chloride to hydroxide concentrations, Cl-/OH-, in crevices increased to levels higher than that of the bulk pore solution, making crevices more vulnerable to depassivation. Therefore, it was concluded that the variability associated with reported chloride thresholds might be attributed, at least in part, to the variability in mill scale properties resulting from the variability in manufacturing. The nano-scale microscopic and spectroscopic studies indicated the formation of 4-10 nm-thick passive oxide films on carbon steel in simulated concrete pore solutions, and these films consisted of two layers separated with an indistinct border. The inner layer was mainly composed of protective Fe2+-rich oxides that are in epitaxial relationship with the underlying steel surface; while the outer layer mostly consisted of (possibly porous) Fe3+-rich oxides, through which chlorides can penetrate. It was proposed that, in the presence of chlorides, Fe+2-rich oxides in the inner layer transform into Fe+3-rich oxides and potentially become un-protective. Although how this transformation occurs is still subject of future research, there are evidences showing that the process most likely leads to the formation of local anodic and cathodic sites on the steel surface.

[In vitro anti-Trichomonas vaginalis effects of a mixture of dihydroartemisinin and metronidazole].

PubMed

Tang, Zi-Hao; Liu, Ke-Yue; Mei, Jun; Gao, Xing-Zheng

2010-12-30

To observe the effect of a mixture of dihydroartemisinin and metronidazole on ultrastructure of Trichomonas vaginalis trophozoites in vitro for exploring trichomonacidal mechanism of the drug mixture. The trophozoites were cultivated with liver extract solution medium that contained 2.5 x 10(6) parasites/ml. There were dihydroartemisinin 0.5 mg/ml and metronidazole 0.002 mg/ml in the experimental tubes of the drug mixture group. Groups of control (without drug), dihydroartemisinin (1 mg/ml) and metronidazole (5 mg/ml) were established and performed in the same experimental conditions. The parasites were observed by scanning and transmission electron microscopes after having treated with the drugs at 37 degrees for 3.5-5 h. Under scanning electron microscope, the cell membrane of T. vaginalis treated only with dihydroartemisinin for 35 h was damaged, part of pellicle peeled off. Although the surface of the trophozoites treated only with metronidazole for 5 h showed many small bubbles and hollows, the cell membrane looked integral. However, surface of the parasite exposed to the drug mixture for 3.5-4.2 h showed deep folds and cracks, the cell membrane was damaged and even peeled off. When the cell ruptured, the nucleus, axostyle, pelta and hydrogenosomes were exposed, and the cytoplasm spilled out. Transmission electron microscopy showed that the membrane system of the trophozoites treated only with dihydroartemisinin for 3.5 h was damaged considerably. The cytoplasm of damaged parasite spilled out. The cytoplasm of the parasite treated only with metronidazole for 3.5-5 h was damaged seriously. Vacuoles and crevices were visible in the cytoplasm. The cell membrane and the content of the parasites treated with the drug mixture for 3.5-4.5 h were damaged seriously. There were some vacuoles and crevices, dilated endoplasmic reticulum, injured and deformed hydrogenosomes in the cytoplasm. The cell organelles mostly disappeared. Crevices also existed in the nucleus. The nuclear membrane fractured and even disappeared. The acting targets of dihydroartemisinin and metronidazole to T. vaginalis trophozoite were different, and a combination of the two drugs shows stronger effect in killing the parasites.

A complex of cardiac cytochrome c1 and cytochrome c.

PubMed

Chiang, Y L; Kaminsky, L S; King, T E

1976-01-10

The interactions of cytochrome c1 and cytochrome c from bovine cardiac mitochondria were investigated. Cytochrome c1 and cytochrome c formed a 1:1 molecular complex in aqueous solutions of low ionic strength. The complex was stable to Sephadex G-75 chromatography. The formation and stability of the complex were independent of the oxidation state of the cytochrome components as far as those reactions studied were concerned. The complex was dissociated in solutions of ionic strength higher than 0.07 or pH exceeding 10 and only partially dissociated in 8 M urea. No complexation occurred when cytochrome c was acetylated on 64% of its lysine residues or photooxidized on its 2 methionine residues. Complexes with molecular ratios of less than 1:1 (i.e. more cytochrome c) were obtained when polymerized cytochrome c, or cytochrome c with all lysine residues guanidinated, or a "1-65 heme peptide" from cyanogen bromide cleavage of cytochrome c was used. These results were interpreted to imply that the complex was predominantly maintained by ionic interactions probably involving some of the lysine residues of cytochrome c but with major stabilization dependent on the native conformations of both cytochromes. The reduced complex was autooxidizable with biphasic kinetics with first order rate constants of 6 X 10(-5) and 5 X U0(-5) s-1 but did not react with carbon monoxide. The complex reacted with cyanide and was reduced by ascorbate at about 32% and 40% respectively, of the rates of reaction with cytochrome c alone. The complex was less photoreducible than cytochrome c1 alone. The complex exhibited remarkably different circular dichroic behavior from that of the summation of cytochrome c1 plus cytochrome c. We concluded that when cytochromes c1 and c interacted they underwent dramatic conformational changes resulting in weakening of their heme crevices. All results available would indicate that in the complex cytochrome c1 was bound at the entrance to the heme crevice of cytochrome c on the methionine-80 side of the heme crevice.

Variability in colony attendance of crevice-nesting horned puffins: Implications for population monitoring

USGS Publications Warehouse

Harding, A.M.A.; Piatt, John F.; Byrd, G.V.; Hatch, Shyla A.; Konyukhov, N.B.; Golubova, E.U.; Williams, J.C.

2005-01-01

It is difficult to survey crevice-nesting seabirds because nest-sites are hard to identify and count, and the number of adult birds attending a colony can be extremely variable within and between days. There is no standardized method for surveying crevice-nesting horned puffins (Fratercula corniculata), and consequently little is known about abundance or changes in their numbers. We examined the variability in colony attendance of horned puffins at 5 breeding colonies in the North Pacific to assess whether variation in count data can be reduced to a level that would allow us to detect changes in the number of birds attending a colony. We used within-year measures of variation in attendance to examine the power to detect a change in numbers between 2 years, and we used measures of among-year variation to examine the power to detect trends over multiple years. Diurnal patterns of attendance differed among colonies, and among-day variation in attendance was generally lowest from mid- to late-incubation to early chick rearing. Within-year variation in water counts was lower than in land counts, and variation was lower using a daily index based on 5 counts per day than it was using 1 count per day. Measures of among-year variation in attendance also were higher for land-based than water-based counts, and they were higher when we used a 10-day survey period than when we used a 30-day period. The use of either 1 or 5 counts a day during the colony-specific diurnal peak of attendance had little influence on levels of among-year variation. Overall, our study suggests that variation in count data may be reduced to a level that allows detection of trends in numbers. However, more studies of interannual variability in horned puffin attendance are needed. Further, the relationship between count data and breeding population size needs more study before the number of birds present at the colony can be used with confidence as an index of population trend.

KSC-98pc418

NASA Image and Video Library

1998-02-27

KENNEDY SPACE CENTER, FLA. -- An oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, is shown in its holding tank in the Space Station Processing Facility. Each fish is between eight and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Since they are bottom dwellers that live in cracks and crevices, a tube is provided in its tank to give it a place to retreat and hide. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. This fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D

KSC-98PC417

NASA Image and Video Library

1998-02-27

KENNEDY SPACE CENTER, FLA. -- Oyster toadfish (Opsanus tau), like those that are part of the Neurolab payload on Space Shuttle Mission STS-90, are shown in their holding tank in the Space Station Processing Facility. Each fish is between 8 and 14 inches long. Toadfish live in an estuarine environment and are native to areas along the Northeast coast of the United States. Since they are bottom dwellers that live in cracks and crevices, tubes are provided in their tank to give them a place to retreat and hide. Investigations during the Neurolab mission will focus on the effects of microgravity on the nervous system. The toadfish fish is an excellent model for looking at vestibular function because the architecture of its inner and middle ear are similar to those of mammals with respect to the vestibular apparatus. The crew of STS-90, slated for launch April 16 at 2:19 p.m. EDT, includes Commander Richard Searfoss, Pilot Scott Altman, Mission Specialists Richard Linnehan, Dafydd (Dave) Williams, M.D., and Kathryn (Kay) Hire, and Payload Specialists Jay Buckey, M.D., and James Pawelczyk, Ph.D

Survival of biofilm-forming Salmonella on stainless steel bolt threads under dry conditions.

PubMed

Morita, Yukio; Komoda, Emiko; Ono, Kazuaki; Kumagai, Susumu

2011-01-01

We examined the survival of two biofilm-forming strains and two biofilm-deficient strains of non typhoid Salmonella (NTS) on stainless steel bolt threads under dry conditions. Five µL of tryptone soya broth or egg yolke mulsion containing NTS strains at a concentration of 9 log cfu/mL was dropped onto the thread surfaces of hexagonal bolts. After inoculation, the bolts were screwed into the nuts, and then removed (Separate type) or not removed (Unit type). The two types of samples were kept in a dry environment (20.0-25.0°C, 2-15% humidity) and bacteria on the surfaces were periodically counted. Biofilm-forming strains were recovered from all samples after 336 days of incubation, but biofilm-deficient strains were isolated from only two of 8 samples after 336 days. This finding demonstrates that NTS can survive for approximately one year on bolt threads, providing direct evidence of the potential risk of constructions having crevices or uneven surfaces as possible contamination sources. The risk of cross-contamination may be higher for biofilm-forming strains than for biofilm-deficient strains.

Chlorpyrifos: an unwelcome pesticide in our homes.

PubMed

Lemus, R; Abdelghani, A

2000-01-01

Chlorpyrifos is an extensively used organophosphate insecticide having many urban and agricultural crop pest control uses. Studies conducted in indoor environments after termiticide, crack-and-crevice, broadcast, or fogger applications have shown that chlorpyrifos exposure can occur via inhalation of residual air concentrations, dermal or oral exposure from residues on floors and carpets, children toys, food, and dust. Not long ago the weight of scientific evidence supported safe indoor use, but recent studies support the possibility that when pregnant female rats are given the pesticide, chlorpyrifos causes brain damage in fetal rats. Moreover, the exposure of young rats to chlorpyrifos impairs early nervous system development. After finding that chlorpyrifos is an exposure risk especially to children, in June 2000 the United States Environmental Protection Agency and manufacturers agreed to voluntary measures that will reduce the exposure of children to chlorpyrifos-containing products. This action implies a search for less harmful new products to replace it and/or safer ways to control pests through basic hygiene. Whichever pest control method is selected, one should keep in mind that preventing environmental pesticide exposure in children is always better than treating the resulting disease.

40 CFR 34.300 - Professional and technical services.

Code of Federal Regulations, 2010 CFR

2010-07-01

... technical services” shall be limited to advice and analysis directly applying any professional or technical... analysis directly applying their professional or technical expertise and unless the advice or analysis is... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Professional and technical services. 34...

Technical Trend of Environment-friendly High Voltage Vacuum Circuit Breaker (VCB)

NASA Astrophysics Data System (ADS)

Okubo, Hitoshi

Vacuum Circuit Breakers (VCBs) have widely been used for low and medium voltage level, because of their high current interruption performance, maintenance free operations and environment-friendly characteristics. The VCB is now going to be applied to higher voltage systems for transmission and substation use. In this paper, the recent technical trend and future perspectives of high voltage VCBs are described, as well as their technical background.

Current limitations into the application of virtual reality to mental health research.

PubMed

Huang, M P; Alessi, N E

1998-01-01

Virtual Reality (VR) environments have significant potential as a tool in mental health research, but are limited by technical factors and by mental health research factors. Technical difficulties include cost and complexity of virtual environment creation. Mental health research difficulties include current inadequacy of standards to specify needed details for virtual environment design. Technical difficulties are disappearing with technological advances, but the mental health research difficulties will take a concerted effort to overcome. Some of this effort will need to be directed at the formation of collaborative projects and standards for how such collaborations should proceed.

Spatially resolved, in-situ monitoring of crack growth via the coupling current in aluminum alloy 5083

NASA Astrophysics Data System (ADS)

Williams, Krystaufeux D.

The work discussed in this dissertation is an experimental validation of a body of research that was created to model stress corrosion cracking phenomenon for 304 stainless steels in boiling water reactors. This coupled environment fracture model (CEFM) incorporates the natural laws of the conservation of charge and the differential aeration hypothesis to predict the amount of stress corrosion crack growth as a function of many external environmental variables, including potential, stress intensity, solution conductivity, oxidizer concentrations, and various other environmental parameters. Out of this approach came the concept of the coupling current; a local corrosion current that flows from within cracks, crevices, pits, etc... of a metal or alloy to the external surface. Because of the deterministic approach taken in the mentioned research, the coupling current analysis and CEFM model can be applied to the specific problem of SCC in aluminum alloy 5083 (the alloy of interest for this dissertation that is highly sought after today because of its corrosion resistance and high strength to weight ratio). This dissertation research is specifically devoted to the experimental verification of the coupling current, which results from a coupling between the crack's internal and external environments, by spatially resolving them using the scanning vibrating probe (SVP) as a tool. Hence, through the use of a unique fracture mechanics setup, simultaneous mechanical and local electrochemical data may be obtained, in situ..

A Description of the Psychological Environment of Students at the Agricultural and Technical College at Delhi.

ERIC Educational Resources Information Center

Bertrami, Anthony

The psychological environment of a college is determined by the inner needs of the students and environmental press, i.e. the stresses, conformity-demanding influence, and rewards of the college. To determine the psychological environment at the Agricultural and Technical College at Delhi, 100 males and 85 females were administered the College…

Mechanical Rope and Cable

DTIC Science & Technology

1975-04-01

seawater. The principal effect of crevices on the corrosion of zinc- or aluminum - coated or uncoated steel rope is to entrap corrosive liquids and...visual inspection of the rope surface. j 5. The effect of stresses, such as tensile, bending, torsion , and comn- pression, upon rope in service is not...questionable A value. d. The effect of stresses, such as tensile, bending, torsion , and compressive contact, on rope is not understood well. 2

Truncated Dual-Cap Nucleation Site Development

NASA Technical Reports Server (NTRS)

Matson, Douglas M.; Sander, Paul J.

2012-01-01

During heterogeneous nucleation within a metastable mushy-zone, several geometries for nucleation site development must be considered. Traditional spherical dual cap and crevice models are compared to a truncated dual cap to determine the activation energy and critical cluster growth kinetics in ternary Fe-Cr-Ni steel alloys. Results of activation energy results indicate that nucleation is more probable at grain boundaries within the solid than at the solid-liquid interface.

METHOD OF IMPROVING CORROSION RESISTANCE OF ZIRCONIUM

DOEpatents

Shannon, D.W.

1961-03-28

An improved intermediate rinse for zirconium counteracts an anomalous deposit that often results in crevices and outof-the-way places when ordinary water is used to rinse away a strong fluoride etching solution designed to promote passivation of the metal. The intermediate rinse, which is used after the etching solution and before the water, is characterized by a complexing agent for fluoride ions such as aluminum or zirconium nitrates or chlorides.

Linear shaped charge

DOEpatents

Peterson, David; Stofleth, Jerome H.; Saul, Venner W.

2017-07-11

Linear shaped charges are described herein. In a general embodiment, the linear shaped charge has an explosive with an elongated arrowhead-shaped profile. The linear shaped charge also has and an elongated v-shaped liner that is inset into a recess of the explosive. Another linear shaped charge includes an explosive that is shaped as a star-shaped prism. Liners are inset into crevices of the explosive, where the explosive acts as a tamper.

Thrips domiciles protect larvae from desiccation in an arid environment

PubMed Central

2014-01-01

Desiccation is a particular risk for small animals in arid environments. In response, many organisms “construct niches,” favorable microenvironments where they spend part or all of their life cycle. Some maintain such environments for their offspring via parental care. Insect eggs are often protected from desiccation by parentally derived gels, casings, or cocoons, but active parental protection of offspring from desiccation has never been demonstrated. Most free-living thrips (Thysanoptera) alleviate water loss via thigmotaxis (crevice seeking). In arid Australia, Acacia thrips (Phlaeothripidae) construct many kinds of niche. Some thrips induce galls; others, like Dunatothrips aneurae, live and breed within “domiciles” made from loosely glued phyllodes. The function of domiciles is unknown; like other constructed niches, they may 1) create favorable microenvironments, 2) facilitate feeding, 3) protect from enemies, or a combination. To test the first 2 alternatives experimentally, field-collected domiciles were destroyed or left intact. Seven-day survival of feeding and nonfeeding larval stages was monitored at high (70–80%) or low (8–10%, approximately ambient) humidity. Regardless of humidity, most individuals survived in intact domiciles, whereas for destroyed domiciles, survival depended on humidity, suggesting parents construct and maintain domiciles to prevent offspring desiccating. Feeding and nonfeeding larvae had similar survival patterns, suggesting the domicile’s role is not nutritional. Outside domiciles, survival at “high” humidity was intermediate, suggesting very high humidity requirements, or energetic costs of wandering outside domiciles. D. aneurae commonly cofound domiciles; cofoundresses may benefit both from shared nestbuilding costs, and from “deferred byproduct mutualism,” that is, backup parental care in case of mortality. PMID:25419084

Part I. Corrosion studies of continuous alumina fiber reinforced aluminum-matrix composites. Part II. Galvanic corrosion between continuous alumina fiber reinforced aluminum-matrix composites and 4340 steel

NASA Astrophysics Data System (ADS)

Zhu, Jun

Part I. The corrosion performance of continuous alumina fiber reinforced aluminum-matrix composites (CF-AMCs) was investigated in both the laboratory and field environments by comparing them with their respective monolithic matrix alloys, i.e., pure Al, A1-2wt%Cu T6, and Al 6061 T6. The corrosion initiation sites were identified by monitoring the changes in the surface morphology. Corrosion current densities and pH profiles at localized corrosion sites were measured using the scanning-vibrating electrode technique and the scanning ion-selective electrode technique, respectively. The corrosion damage of the materials immersed in various electrolytes, as well as those exposed in a humidity chamber and outdoor environments, was evaluated. Potentiodynamic polarization behavior was also studied. The corrosion initiation for the composites in 3.15 wt% NaCl occurred primarily around the Fe-rich intermetallic particles, which preferentially existed around the fiber/matrix interface on the composites. The corrosion initiation sites were also caused by physical damage (e.g., localized deformation) to the composite surface. At localized corrosion sites, the buildup of acidity was enhanced by the formation of micro-crevices resulting from fibers left in relief as the matrix corroded. The composites that were tested in exposure experiments exhibited higher corrosion rates than their monolithic alloys. The composites and their monolithic alloys were subjected to pitting corrosion when anodically polarized in the 3.15 wt% NaCl, while they passivated when anodically polarized in 0.5 M Na2SO4. The experimental results indicated that the composites exhibited inferior corrosion resistance compared to their monolithic matrix alloys. Part II. Galvanic corrosion studies were conducted on CF-AMCs coupled to 4340 steel since CF-AMCs have low density and excellent mechanical properties and are being considered as potential jacketing materials for reinforcing steel gun barrels. Coupled and uncoupled coupons were immersed in various electrolytes, exposed to a humidity chamber, and exposed at outdoor test sites. Results showed that the corrosion rates of the CF-AMCs increased, while those of the 4340 steel decreased after being coupled together, in most cases. Crevice corrosion was also observed in these exposure experiments. Zero resistance ammeter (ZRA) experiments were conducted to record the galvanic-corrosion rates and potentials of the couples. The CF-AMCs were found to serve as anodes, while the steel was cathodic, in most test conditions. Galvanic performance predicted by polarization experiments was in close agreement with the ZRA results. Key words. Aluminum, metal-matrix composites, alumina fiber, pitting corrosion, galvanic corrosion.

Can gingival crevicular blood be relied upon for assessment of blood glucose level?

PubMed

Dwivedi, Shivani; Verma, Sharmila J; Shah, Monali; Jain, Kapil

2014-11-01

Diabetes mellitus (DM) is undiagnosed in approximately half of the patients actually suffering from the disease. In addition, the prevalence of DM is more than twice as high as in patients with periodontitis when compared to periodontally healthy subjects. Thus, a high number of patients with periodontitis may have undiagnosed DM. The purpose of the present study was to evaluate whether blood oozing from a gingival crevice during routine periodontal examination can be used for determining glucose levels. Observational cross-sectional studies were carried out in 75 patients (43 males and 32 females) with chronic periodontitis who were divided into two groups: Group I and Group II, respectively. Blood oozing from the gingival crevices of anterior teeth following periodontal probing was collected with the stick of glucose self-monitoring device, and the blood glucose levels were measured. At the same time, finger-prick blood was taken for glucometric analysis and subsequent readings were recorded. The patient's blood glucose values ranged from 74 to 256 mg/dl. The comparison between gingival crevicular blood and finger-prick blood showed a very strong correlation, with a t value of 3.97 (at P value = 0.001). The data from this study has shown that GCB collected during diagnostic periodontal examination can be an excellent source of blood for glucometric analysis.

Innovative Socio-Technical Environments in Support of Distributed Intelligence and Lifelong Learning

ERIC Educational Resources Information Center

Fischer, G; Konomi, S.

2007-01-01

Individual, unaided human abilities are constrained. Media have helped us to transcend boundaries in thinking, working, learning and collaborating by supporting "distributed intelligence". Wireless and mobile technologies provide new opportunities for creating novel socio-technical environments and thereby empowering humans, but not without…

Our built and natural environments : a technical review of the interactions between land use, transportation, and environmental quality

DOT National Transportation Integrated Search

2001-01-01

In recent years interest has grown in Smart Growth as a mechanism for improving environmental quality. In Our Built and Natural Environments, the U.S. Environmental Protection Agency (EPA) summarizes technical research on the relationship between the...

40 CFR 34.300 - Professional and technical services.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Professional and technical services. 34.300 Section 34.300 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE NEW RESTRICTIONS ON LOBBYING Activities by Other Than Own Employees § 34.300 Professional and...

The French Space Operation Act: Technical Regulations

NASA Astrophysics Data System (ADS)

Trinchero, J. P.; Lazare, B.

2010-09-01

The French Space Operation Act(FSOA) stipulates that a prime objective of the National technical regulations is to protect people, property, public health and the environment. Compliance with these technical regulations is mandatory as of 10 December 2010 for space operations by French space operators and for space operations from French territory. The space safety requirements and regulations governing procedures are based on national and international best practices and experience. A critical design review of the space system and procedures shall be carried out by the applicant, in order to verify compliance with the Technical Regulations. An independent technical assessment of the operation is delegated to CNES. The principles applied when drafting technical regulations are as follows: requirements must as far as possible establish the rules according to the objective to be obtained, rather than how it is to be achieved; requirements must give preference to international standards recognised as being the state of the art; requirements must take previous experience into account. Technical regulations are divided into three sections covering common requirements for the launch, control and return of a space object. A dedicated section will cover specific rules to be applied at the Guiana Space Centre. The main topics addressed by the technical regulations are: operator safety management system; study of risks to people, property, public health and the Earth’s environment; impact study on the outer space environment: space debris generated by the operation; planetary protection.

Organizational Routines as Coupling Mechanisms: Policy, School Administration, and the Technical Core

ERIC Educational Resources Information Center

Spillane, James P.; Parise, Leigh Mesler; Sherer, Jennifer Zoltners

2011-01-01

The institutional environment of America's schools has changed substantially as government regulation has focused increasingly on the core technical work of schools--instruction. The authors explore the school administrative response to this changing environment, describing how government regulation becomes embodied in the formal structure of four…

40 CFR 35.4190 - How does my group identify a qualified technical advisor?

Code of Federal Regulations, 2013 CFR

2013-07-01

... health, environmental sciences, engineering, environmental law and planning); and (3) Ability to... 40 Protection of Environment 1 2013-07-01 2013-07-01 false How does my group identify a qualified technical advisor? 35.4190 Section 35.4190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS...

40 CFR 35.4190 - How does my group identify a qualified technical advisor?

Code of Federal Regulations, 2014 CFR

2014-07-01

... health, environmental sciences, engineering, environmental law and planning); and (3) Ability to... 40 Protection of Environment 1 2014-07-01 2014-07-01 false How does my group identify a qualified technical advisor? 35.4190 Section 35.4190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS...

40 CFR 35.4190 - How does my group identify a qualified technical advisor?

Code of Federal Regulations, 2012 CFR

2012-07-01

... health, environmental sciences, engineering, environmental law and planning); and (3) Ability to... 40 Protection of Environment 1 2012-07-01 2012-07-01 false How does my group identify a qualified technical advisor? 35.4190 Section 35.4190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS...

National Data Program for the Marine Environment Technical Development Plan. Final Report, Volume Two.

ERIC Educational Resources Information Center

System Development Corp., Santa Monica, CA.

A national data program for the marine environment is recommended. Volume 2 includes: (1) objectives, scope, and methodology; (2) summary of the technical development plan; (3) agency development plans - Great Lakes and coastal development and (4) marine data network development plans. (Author)

Corrosion and fatigue of surgical implants

NASA Technical Reports Server (NTRS)

Lisagor, W. B.

1975-01-01

Implants for the treatment of femoral fractures, mechanisms leading to the failure or degradation of such structures, and current perspectives on surgical implants are discussed. Under the first heading, general usage, materials and procedures, environmental conditions, and laboratory analyses of implants after service are considered. Corrosion, crevice corrosion, stress corrosion cracking, intergranular corrosion, pitting corrosion, fatigue, and corrosion fatigue are the principal degradation mechanisms described. The need for improvement in the reliability of implants is emphasized.

[Developmental radicular groove as a cause of endodontic failure].

PubMed

Fabra Campos, H; Millet Part, J

1989-01-01

A clinical case of apical injury on an upper lateral incisor with endodontical and surgical failures in its treatment is presented. Extraction of the incisor and its study at the stereoscopic microscope showed the existence of a developmental groove running from the cingulum to the end of the root, establishing a communication between the crevice and the apical part of the tooth. Bacterial infection through the groove could provide an explanation for treatment failure.

Crevice Corrosion Behavior of 45 Molybdenum-Containing Stainless Steels in Seawater.

DTIC Science & Technology

1981-12-01

Armco, Avesta Jernverks, Cabot, Carpenter Technology, Crucible, Eastern, Firth-Brown, Huntington, Jessup, Langley Alloys, and Uddeholm. 16...Department of Energy, Report ANL/OTEC-BCM-022. 7. Wallen, B., and M. Liljas, " Avesta 254 SMO - A New, High Molybdenum Stainless Steel," presented at NKM8...1977).; 11. Wallen, B., " Avesta 254 SMO - A Stainless Steel for Seawater Service," presented at the Advanced Stainless Steels for Turbine Condensors

New Desktop Virtual Reality Technology in Technical Education

ERIC Educational Resources Information Center

Ausburn, Lynna J.; Ausburn, Floyd B.

2008-01-01

Virtual reality (VR) that immerses users in a 3D environment through use of headwear, body suits, and data gloves has demonstrated effectiveness in technical and professional education. Immersive VR is highly engaging and appealing to technically skilled young Net Generation learners. However, technical difficulty and very high costs have kept…

40 CFR 34.205 - Professional and technical services.

Code of Federal Regulations, 2010 CFR

2010-07-01

...” shall be limited to advice and analysis directly applying any professional or technical discipline. For... applying their professional or technical expertise and unless the advice or analysis is rendered directly... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Professional and technical services. 34...

Exploring the Benefits of Teacher-Modeling Strategies Integrated into Career and Technical Education

ERIC Educational Resources Information Center

Cathers, Thomas J., Sr.

2013-01-01

This case study examined how career and technical education classes function using multiple instructional modeling strategies integrated into vocational and technical training environments. Seven New Jersey public school technical teachers received an introductory overview of the investigation and participated by responding to 10 open-end…

40 CFR 35.4190 - How does my group identify a qualified technical advisor?

Code of Federal Regulations, 2010 CFR

2010-07-01

... technical advisor? 35.4190 Section 35.4190 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Technical Assistance Procuring A Technical Advisor Or Other Contractor with Tag Funds § 35.4190 How does my group identify a qualified...

Technical Writing: Past, Present, and Future.

ERIC Educational Resources Information Center

Mathes, J. C., Comp.; Pinelli, Thomas E., Comp.

This compilation of papers addresses the history, present status, and trends of technical and related writing. The first of the eight papers surveys the present environment of the technical report and assesses the effectiveness of the technical report format of the National Aeronautics and Space Administration (NASA) in transmitting information.…

40 CFR 34.205 - Professional and technical services.

Code of Federal Regulations, 2011 CFR

2011-07-01

...” shall be limited to advice and analysis directly applying any professional or technical discipline. For... applying their professional or technical expertise and unless the advice or analysis is rendered directly... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Professional and technical services. 34...

Learning Objects and Virtual Learning Environments Technical Evaluation Criteria

ERIC Educational Resources Information Center

Kurilovas, Eugenijus; Dagiene, Valentina

2009-01-01

The main scientific problems investigated in this article deal with technical evaluation of quality attributes of the main components of e-Learning systems (referred here as DLEs--Digital Libraries of Educational Resources and Services), i.e., Learning Objects (LOs) and Virtual Learning Environments (VLEs). The main research object of the work is…

Three-dimensional interstitial space mediates predator foraging success in different spatial arrangements.

PubMed

Hesterberg, Stephen G; Duckett, C Cole; Salewski, Elizabeth A; Bell, Susan S

2017-04-01

Identifying and quantifying the relevant properties of habitat structure that mediate predator-prey interactions remains a persistent challenge. Most previous studies investigate effects of structural density on trophic interactions and typically quantify refuge quality using one or two-dimensional metrics. Few consider spatial arrangement of components (i.e., orientation and shape) and often neglect to measure the total three-dimensional (3D) space available as refuge. This study tests whether the three-dimensionality of interstitial space, an attribute produced by the spatial arrangement of oyster (Crassostrea virginica) shells, impacts the foraging success of nektonic predators (primary blue crab, Callinectes sapidus) on mud crab prey (Eurypanopeus depressus) in field and mesocosm experiments. Interstices of 3D-printed shell mimics were manipulated by changing either their orientation (angle) or internal shape (crevice or channel). In both field and mesocosm experiments, under conditions of constant structural density, predator foraging success was influenced by 3D aspects of interstitial space. Proportional survivorship of tethered mud crabs differed significantly as 3D interstitial space varied by orientation, displaying decreasing prey survivorship as angle of orientation increased (0° = 0.76, 22.5° = 0.13, 45° = 0.0). Tethered prey survivorship was high when 3D interstitial space of mimics was modified by internal shape (crevice survivorship = 0.89, channel survivorship = 0.96) and these values did not differ significantly. In mesocosms, foraging success of blue crabs varied with 3D interstitial space as mean proportional survivorship (± SE) of mud crabs was significantly lower in 45° (0.27 ± 0.06) vs. 0° (0.86 ± 0.04) orientations and for crevice (0.52 ± 0.11) vs. channel shapes (0.95 ± 0.02). These results suggest that 3D aspects of interstitial space, which have direct relevance to refuge quality, can strongly influence foraging success in our oyster reef habitat. Our findings highlight the importance of spatial arrangement in mediating consumptive pathways in hard-structured habitats and demonstrate how quantifying the three-dimensionality of living space captures aspects of habitat structure that have been missing from previous empirical studies of trophic interactions and structural complexity. © 2017 by the Ecological Society of America.

Passive Films, Surface Structure and Stress Corrosion and Crevice Corrosion Susceptibility.

DTIC Science & Technology

1980-08-01

with pure titanium ( 4 ], it is of interest to pursue the effects on titanium -palladium alloys, to evaluate their susceptibility to stress corrosion...cracking due to hydrogen embrittlement with the field ion microscope, and to compare the results with those previously obtained with pure titanium [ 4 ...characterized as 99.99+ percent pure, and was used in the previous field ion microscopy study of titanium [ 4 ], where it was found that strain annealing titanium

Effect of chlorides on solution corrosivity of methyldiethanolamine (MDEA) solutions

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

Rooney, P.C.; Bacon, T.R.; DuPart, M.S.

1997-08-01

Solution corrosivity of MDEA/water solutions containing added HCl or NaCl have been measured by weight loss coupons at 250 F and by linear polarization resistance (LPR) at 208 F using carbon steel, 304SS, 316SS and 410SS. General corrosion as well as pitting or crevice corrosion tendencies were recorded for each species. Based on these results, recommendations are made for chlorides in MDEA that minimizes corrosion in gas treating operations.

Passive Films, Surface Structure and Stress Corrosion and Crevice Corrosion Susceptibility.

DTIC Science & Technology

1983-11-01

thiadiazole ( DMTDA ), when dispersed in the coating were observed to delay the onset of delamifnation. Catechol was found to be an ineffective inhibitor. A...similar beneficial effect was noted with a two-layer system employing a zinc chromate primer. However, when 8-HQ and DMTDA were applied by an anodic...shows the ellipsometric responses for the iron/acrylic system with DMTDA dispersed in the coating. The pre-puncture signals suggest changes in surface

Seawater Corrosion of Fasteners in Various Structural Materials

DTIC Science & Technology

1976-04-01

17 - 4PH stainless steel. The seven bolt materials were: 2024 aluminum, anodized ASTM grade 5 steel, 304 and 316 stainless steels, A286 stain- less...performed well in titanium structures. Use of MP35N, A286, and 304 stainless steel fasteners for constantly immersed 17 - 4PH stainless steel structures...would have been satisfactory only if sealant was not used and if protection had been provided to the 17 - 4PH to minimize crevice corrosion. Additional

Predation cues rather than resource availability promote cryptic behaviour in a habitat-forming sea urchin.

PubMed

Spyksma, Arie J P; Taylor, Richard B; Shears, Nick T

2017-03-01

It is well known that predators often influence the foraging behaviour of prey through the so-called "fear effect". However, it is also possible that predators could change prey behaviour indirectly by altering the prey's food supply through a trophic cascade. The predator-sea urchin-kelp trophic cascade is widely assumed to be driven by the removal of sea urchins by predators, but changes in sea urchin behaviour in response to predators or increased food availability could also play an important role. We tested whether increased crevice occupancy by herbivorous sea urchins in the presence of abundant predatory fishes and lobsters is a response to the increased risk of predation, or an indirect response to higher kelp abundances. Inside two New Zealand marine reserves with abundant predators and kelp, individuals of the sea urchin Evechinus chloroticus were rarer and remained cryptic (i.e. found in crevices) to larger sizes than on adjacent fished coasts where predators and kelp are rare. In a mesocosm experiment, cryptic behaviour was induced by simulated predation (the addition of crushed conspecifics), but the addition of food in the form of drift kelp did not induce cryptic behaviour. These findings demonstrate that the 'fear' of predators is more important than food availability in promoting sea urchin cryptic behaviour and suggest that both density- and behaviourally mediated interactions are important in the predator-sea urchin-kelp trophic cascade.

Stereo imaging and cytocompatibility of a model dental implant surface formed by direct laser fabrication.

PubMed

Mangano, Carlo; Raspanti, Mario; Traini, Tonino; Piattelli, Adriano; Sammons, Rachel

2009-03-01

Direct laser fabrication (DLF) allows solids with complex geometry to be produced by sintering metal powder particles in a focused laser beam. In this study, 10 Ti6Al4V alloy model dental root implants were obtained by DLF, and surface characterization was carried out using stereo scanning electron microscopy to produce 3D reconstructions. The surfaces were extremely irregular, with approximately 100 microm deep, narrow intercommunicating crevices, shallow depressions and deep, rounded pits of widely variable shape and size, showing ample scope for interlocking with the host bone. Roughness parameters were as follows: R(t), 360.8 microm; R(z), 358.4 microm; R(a), 67.4 microm; and R(q), 78.0 microm. Disc specimens produced by DLF with an identically prepared surface were used for biocompatibility studies with rat calvarial osteoblasts: After 9 days, cells had attached and spread on the DLF surface, spanning across the crevices, and voids. Cell density was similar to that on a commercial rough microtextured surface but lower than on commercial smooth machined and smooth-textured grit-blasted, acid-etched surfaces. Human fibrin clot extension on the DLF surface was slightly improved by inorganic acid etching to increase the microroughness. With further refinements, DLF could be an economical means of manufacturing implants from titanium alloys. (c) 2008 Wiley Periodicals, Inc.

Geochemical evidence for hydroclimatic variability over the last 2460 years from Crevice Lake in Yellowstone National Park, USA

USGS Publications Warehouse

Stevens, L.R.; Dean, W.E.

2008-01-01

A 2460-year-long hydroclimatic record for Crevice Lake, Yellowstone National Park, Montana was constructed from the ??18O values of endogenic carbonates. The ??18O record is compared to the Palmer Hydrologic Drought Index (PHDI) and Pacific Decadal Oscillation (PDO) indices, as well as inferred discharge of the Yellowstone River. During the last century, high ??18O values coincide with drought conditions and the warm phase of the PDO index. Low ??18O values coincide with wet years and a negative PDO index. Comparison of tree-ring inferred discharge of the Yellowstone River with the ??18O record over the last 300 years indicates that periods of high discharge (i.e., wet winters with significant snow pack) correspond with low ??18O values. Extrapolating this relationship we infer wet winters and high river discharge for the periods of 1090-1030, 970-870, 670-620, and 500-430 cal years BP. The wet intervals at 670 and 500 cal BP are synchronous with similar events in Banff, Canada and Walker Lake, Nevada. The wet intervals at 970 and 670 cal BP overlap with wet intervals at Walker Lake and major drought events identified in the western Great Basin. These results suggest that the northern border of Yellowstone National Park straddles the boundary between Northern Rocky Mountains and Great Basin climate regimes. ?? 2007 Elsevier Ltd and INQUA.

Anodized titanium and stainless steel in contact with CFRP: an electrochemical approach considering galvanic corrosion.

PubMed

Mueller, Yves; Tognini, Roger; Mayer, Joerg; Virtanen, Sannakaisa

2007-09-15

The combination of different materials in an implant gives the opportunity to better fulfill the requirements that are needed to improve the healing process. However, using different materials increases the risk of galvanic coupling corrosion. In this study, coupling effects of gold-anodized titanium, stainless steel for biomedical applications, carbon fiber reinforced polyetheretherketone (CFRP), and CFRP containing tantalum fibers are investigated electrochemically and by long-term immersion experiments in simulated body fluid (SBF). Potentiodynamic polarization experiments (i/E curves) and electrochemical impedance spectroscopy (EIS) of the separated materials showed a passive behavior of the metallic samples. Anodized titanium showed no corrosion attacks, whereas stainless steel is highly susceptibility for localized corrosion. On the other side, an active dissolution behavior of both of the CFRPs in the given environment could be determined, leading to delaminating of the carbon fibers from the matrix. Long-term immersion experiments were carried out using a set-up especially developed to simulate coupling conditions of a point contact fixator system (PC-Fix) in a biological environment. Electrochemical data were acquired in situ during the whole immersion time. The results of the immersion experiments correlate with the findings of the electrochemical investigation. Localized corrosion attacks were found on stainless steel, whereas anodized titanium showed no corrosion attacks. No significant differences between the two CFRP types could be found. Galvanic coupling corrosion in combination with crevice conditions and possible corrosion mechanisms are discussed. Copyright 2007 Wiley Periodicals, Inc.

Pedagogical, Social and Technical Designs of a Blended Synchronous Learning Environment

ERIC Educational Resources Information Center

Wang, Qiyun; Huang, Changqin

2018-01-01

In this study, a blended synchronous learning environment (BSLE) was designed from pedagogical, social and technical perspectives. It was created for a group of master's students to attend lessons in the classroom and at the same time allow a few of them to join the identical sessions using video conferencing from different sites. The purpose of…

Concepts for a NASA Applied Spaceflight Environments Office

NASA Technical Reports Server (NTRS)

Edwards, David L.; Burns, Howard D.; Xapsos, Michael; Spann, Jim; Suggs, Robert

2010-01-01

The National Aeronautics and Space Administration (NASA) is launching a bold and ambitious new space initiative. A significant part of this new initiative includes exploration of new worlds, the development of more innovative technologies, and expansion our presence in the solar system. A common theme to this initiative is the exploration of space beyond Low Earth Orbit (LEO). As currently organized, NASA does not have an Agency-level office that provides coordination of space environment research and development. This has contributed to the formation of a gap between spaceflight environments knowledge and the application of this knowledge for multi-program use. This paper outlines a concept to establish a NASA-level Applied Spaceflight Environments (ASE) office that will provide coordination and funding for sustained multi-program support in three technical areas that have demonstrated these needs through customer requests. These technical areas are natural environments characterization and modeling, materials and systems analysis and test, and operational space environments modeling and prediction. This paper will establish the need for the ASE, discuss a concept for organizational structure and outline the scope in the three technical areas

Ants learn to rely on more informative attributes during decision-making.

PubMed

Sasaki, Takao; Pratt, Stephen C

2013-01-01

Evolutionary theory predicts that animals act to maximize their fitness when choosing among a set of options, such as what to eat or where to live. Making the best choice is challenging when options vary in multiple attributes, and animals have evolved a variety of heuristics to simplify the task. Many of these involve ranking or weighting attributes according to their importance. Because the importance of attributes can vary across time and place, animals might benefit by adjusting weights accordingly. Here, we show that colonies of the ant Temnothorax rugatulus use their experience during nest site selection to increase weights on more informative nest attributes. These ants choose their rock crevice nests on the basis of multiple features. After exposure to an environment where only one attribute differentiated options, colonies increased their reliance on this attribute relative to a second attribute. Although many species show experience-based changes in selectivity based on a single feature, this is the first evidence in animals for adaptive changes in the weighting of multiple attributes. These results show that animal collectives, like individuals, change decision-making strategies according to experience. We discuss how these colony-level changes might emerge from individual behaviour.

Morphological characterization of as-received and in vivo orthodontic stainless steel archwires.

PubMed

Daems, Julie; Celis, Jean-Pierre; Willems, Guy

2009-06-01

This study was undertaken to evaluate the material degradation of clinical bracket-archwire-contacting surfaces after in vivo orthodontic use. Twenty-four stainless steel multiloop edgewise archwires with two different cross sections (0.016 x 0.016 and 0.016 x 0.022 inches) were used for at least 6 months in the mouths of 14 patients. The surfaces of both as-received (cross-section of 0.016 x 0.016, 0.016 x 0.022, and 0.017 x 0.025 inches) and the in vivo wires were examined using scanning electron microscopy. The as-received wires exhibited an inhomogeneous surface with different surface irregularities resulting from the manufacturing process. For the in vivo archwires, an increase in the variety, type, and number of surface irregularities were observed. Crevice corrosion occurred not only at surface irregularities formed during manufacturing and orthodontic handling but also at the bracket-archwire-contacting surfaces and at the archwire surfaces coated with plaque and food remnants. This corrosion may be linked to the formation of a micro-environment at these locations. In addition, a limited number of signs of degradation induced during in vivo testing due to wear and friction were observed.

Effect of cloric acid concentration on corrosion behavior of Ni/Cr coated on carbon steel

NASA Astrophysics Data System (ADS)

Desiati, Resetiana Dwi; Sugiarti, Eni; Thosin, K. A. Zaini

2018-05-01

Corrosion is one of the causes of metal degradation. Carbon steel (Fe) is easy to corrode in the extreme environment. Coating on carbon steel is required to improve corrosion resistance owing to protection or hindrance to extreme environmental conditions. In this present work, carbon steel was coated by electroplating techniques for nickel and pack cementation for chrome. The corrosion rate test was performed by Weight Loss method on FeNiCr, FeNi, FeCr and uncoated Fe as comparator which was dyed in 37% HCl and 25% HCl which had previously been measured dimension and mass. The immersion test result of FeNiCr and FeNi specimen were better than FeCr and uncoated Fe in terms of increasing corrosion resistance. The corrosion rate for 56 hours in 37% HCl for FeNiCr was 1.592 mm/y and FeNi was 3.208 mm/y, FeCr only lasted within 32 hours with corrosion rate was 6.494 mm/y. Surface of the sample after the corrosion test there was pitting, crevice corrosion and alloy cracking caused by chloride. The higher the concentration of HCl the faster the corrosion rate.

40 CFR 35.4185 - What does my group do with reports our technical advisor prepares for us?

Code of Federal Regulations, 2010 CFR

2010-07-01

... technical advisor prepares for us? 35.4185 Section 35.4185 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Technical Assistance Managing Your Tag § 35.4185 What does my group do with reports our technical advisor prepares for...

40 CFR 35.4205 - How does my group procure a technical advisor or any other contractor?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false How does my group procure a technical... PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Technical Assistance Procuring A Technical Advisor Or Other Contractor with Tag Funds § 35.4205 How does my group...

Atmospheric/Space Environment Support Lessons Learned Regarding Aerospace Vehicle Design and Operations

NASA Technical Reports Server (NTRS)

Vaughan, William W.; Anderson, B. Jeffrey

2005-01-01

In modern government and aerospace industry institutions the necessity of controlling current year costs often leads to high mobility in the technical workforce, "one-deep" technical capabilities, and minimal mentoring for young engineers. Thus, formal recording, use, and teaching of lessons learned are especially important in the maintenance and improvement of current knowledge and development of new technologies, regardless of the discipline area. Within the NASA Technical Standards Program Website http://standards.nasa.gov there is a menu item entitled "Lessons Learned/Best Practices". It contains links to a large number of engineering and technical disciplines related data sets that contain a wealth of lessons learned information based on past experiences. This paper has provided a small sample of lessons learned relative to the atmospheric and space environment. There are many more whose subsequent applications have improved our knowledge of the atmosphere and space environment, and the application of this knowledge to the engineering and operations for a variety of aerospace programs.

40 CFR 52.1110 - Small business stationary source technical and environmental compliance assistance program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... technical and environmental compliance assistance program. 52.1110 Section 52.1110 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS (CONTINUED) Maryland § 52.1110 Small business stationary source technical and environmental...

Global hexachlorocyclohexane use trends and their impact on the Arctic atmospheric environment

NASA Astrophysics Data System (ADS)

Li, Y. F.; Bidleman, T. F.; Barrie, L. A.; McConnell, L. L.

The relationship between the global technical HCH use trends and their impact on the arctic atmospheric environment has been studied. Two significant drops in global technical HCH usage were identified. In 1983, China banned the use of technical HCH. This represented the largest drop ever in global use rates. In 1990 India stopped technical HCH usage in agriculture and the former Soviet Union banned the use of technical HCH. Since 1990, India has been the biggest user of technical HCH in the world. Significant drops in atmospheric α-HCH in the arctic were observed between 1982 and 1983, and again between 1990 and 1992. The rapid response in atmospheric concentrations to usage is encouraging; however, since α-HCH concentrations in the arctic waters have remained relatively unchanged, the decline in atmospheric α-HCH has reversed the net direction of air-sea gas flux. The accumulated mass in oceans and large lakes may represent a new source of HCH to the arctic atmosphere.

Influences of Gender and Computer Gaming Experience in Occupational Desktop Virtual Environments: A Cross-Case Analysis Study

ERIC Educational Resources Information Center

Ausburn, Lynna J.; Ausburn, Floyd B.; Kroutter, Paul J.

2013-01-01

This study used a cross-case analysis methodology to compare four line-of-inquiry studies of desktop virtual environments (DVEs) to examine the relationships of gender and computer gaming experience to learning performance and perceptions. Comparison was made of learning patterns in a general non-technical DVE with patterns in technically complex,…

An analytical investigation of NO sub x control techniques for methanol fueled spark ignition engines

NASA Technical Reports Server (NTRS)

Browning, L. H.; Argenbright, L. A.

1983-01-01

A thermokinetic SI engine simulation was used to study the effects of simple nitrogen oxide control techniques on performance and emissions of a methanol fueled engine. As part of this simulation, a ring crevice storage model was formulated to predict UBF emissions. The study included spark retard, two methods of compression ratio increase and EGR. The study concludes that use of EGR in high turbulence, high compression engines will both maximize power and thermal efficiency while minimizing harmful exhaust pollutants.

Attachment Levels and Crevicular Depths at the Distal of Mandibular Second Molars Following Removal of Adjacent Third Molars.

DTIC Science & Technology

1981-02-01

attachment by determining the distance between the bottom of the crevice and the cemento -enamel junction prior to surgery were unsuccessful, but they were...measuring from the tips of the distolingual and distobuccal cusps and the midpoint of the distal marginal ridge (the cemento -enamel junction could not be...The cemento -enamel junction, usually used as a refer- ence point for determining attachment level, could not be visualized on the distal of the

Ultrasound-induced inertial cavitation from gas-stabilizing nanoparticles.

PubMed

Kwan, J J; Graham, S; Myers, R; Carlisle, R; Stride, E; Coussios, C C

2015-08-01

The understanding of cavitation from nanoparticles has been hindered by the inability to control nanobubble size. We present a method to manufacture nanoparticles with a tunable single hemispherical depression (nanocups) of mean diameter 90, 260, or 650 nm entrapping a nanobubble. A modified Rayleigh-Plesset crevice model predicts the inertial cavitation threshold as a function of cavity size and frequency, and is verified experimentally. The ability to tune cavitation nanonuclei and predict their behavior will be useful for applications ranging from cancer therapy to ultrasonic cleaning.

Cavitation Inception Scale Effects. 1. Nuclei Distributions in Natural Waters. 2. Cavitation Inception in a Turbulent Shear Flow.

DTIC Science & Technology

1987-05-01

ratio of specific heats for the gas and an adiabatic bubble pressure- volume relation has been assumed (Plesset & Prosperetti 1977). When viscosity...pressure because of surface tension at the gas -liquid interface , so the gas is stabilized in the crevice and will not dissolve into the liquid. The concave... interface toward the gas is estab- lished by the hydrophobic nature of the particle, and results in surface tension acting to oppose the liquid

Scaffolding Collaborative Technical Writing with Procedural Facilitation and Synchronous Discussion

ERIC Educational Resources Information Center

Yeh, Shiou-Wen; Lo, Jia-Jiunn; Huang, Jeng-Jia

2011-01-01

With the advent of computer technology, researchers and instructors are attempting to devise computer support for effective collaborative technical writing. In this study, a computer-supported environment for collaborative technical writing was developed. This system (Process-Writing Wizard) provides process-oriented scaffolds and a synchronous…

NATIONAL RESPONSE TEAM TECHNICAL ASSISTANCE ...

EPA Pesticide Factsheets

This document provides technical information on a wide range of activities to aid in response to intentional release of anthrax in urban environments. It includes initial actions when a potential release is discovered, health and safety issues for responders, sampling and analysis methods, decontamination technologies, decontamination waste disposal, and communication with public. This document provides technical information on a wide range of activities to aid in response to intentional release of anthrax in urban environments. It includes initial actions when a potential release is discovered, health and safety issues for responders, sampling and analysis methods, decontamination technologies, decontamination waste disposal, and communication with public.

Analysis of Student Perceptions of the Psychosocial Learning Environment in Online and Face-to-Face Career and Technical Education Courses

ERIC Educational Resources Information Center

Carver, Diane L.; Kosloski, Michael F., Jr.

2015-01-01

This study analyzed student perceptions of the psychosocial learning environment in online and face-to-face career and technical education courses, and used survey data from a school district in Washington state. A Mann-Whitney "U" test was used to measure variability and compare the mean scores for a series of psychosocial learning…

An Examination of the Benefits and Costs of Sabbatical Leave for General Higher Education, Industry, and Professional-Technical/Community College Environments

ERIC Educational Resources Information Center

Otto, Linda R.; Kroth, Michael

2011-01-01

The purpose of this literature review is to examine the differences in the use of sabbatical leave among the arenas of general higher education, industry, and professional-technical/community college. The purposes and policies applied to sabbatical leave, along with the cost of using sabbatical leave in these three environments are compared and…

Quad Charts in the Classroom to Reinforce Technical Communication Fundamentals

ERIC Educational Resources Information Center

Ford, Julie Dyke; Wei, Tie

2015-01-01

Quad charts are a genre frequently used in scientific and technical environments, yet little prior work has evaluated their potential for reinforcing technical communication fundamentals. This article provides background information about quad charts and notes the benefits of implementing quad charts in the classroom. In particular, introducing…

Differentiated Technical Assistance for Sustainable Transformation. Technical Assistance Brief #2

ERIC Educational Resources Information Center

McCart, Amy; McSheehan, Michael; Sailor, Wayne

2015-01-01

Schoolwide Integrated Framework for Transformation (SWIFT) Center's technical assistance process supports states, districts, and schools as they become excellent and equitable teaching and learning environments for "all" students. Each school with support from its district begins this process from its own starting point and travels its…

A Green Campus Culture in Wisconsin

ERIC Educational Resources Information Center

Jorgensen, Haley

2006-01-01

This article features information about the Nicolet Area Technical College in Rhinelander, Wisconsin for preserving the environment as a school-wide initiative. In 2003, Nicolet became the first of the state's 16 technical colleges to embrace a campus-wide focus on renewable energy. In cooperation with the Wisconsin Technical College System…

40 CFR 58.11 - Network technical requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Network technical requirements. 58.11... (CONTINUED) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.11 Network technical requirements. (a)(1... A to this part when operating the SLAMS networks. (2) Beginning January 1, 2009, State and local...

40 CFR 58.11 - Network technical requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Network technical requirements. 58.11... (CONTINUED) AMBIENT AIR QUALITY SURVEILLANCE Monitoring Network § 58.11 Network technical requirements. (a)(1... A to this part when operating the SLAMS networks. (2) Beginning January 1, 2009, State and local...

The Technical Communicator as Corporate Spokesperson: A Public Relations Primer.

ERIC Educational Resources Information Center

Troester, Rod; Warburton, Terrence L.

2001-01-01

Examines the changing role of the technical communication professional in the rapidly evolving environment of organizational life. Presents five principles that serve as an initial step in laying a foundation for the preparation of technical communicators for the challenges and opportunities awaiting in contemporary organizations and the…

A NASA Applied Spaceflight Environments Office Concept

NASA Technical Reports Server (NTRS)

Spann, James F.; Edwards, David L.; Burns, Howard D.; Xapsos, Mike

2011-01-01

The National Aeronautics and Space Administration (NASA) is launching a bold and ambitious new space initiative. A significant part of this new initiative includes exploration of new worlds, the development of more innovative technologies, and expansion our presence in the solar system. A common theme to this initiative is the exploration of space beyond Low Earth Orbit (LEO). As currently organized, NASA does not have an Agency-level office that provides coordination of space environment research and development. This has contributed to the formation of a gap between spaceflight environments knowledge and the application of this knowledge for multi-program use and for use outside NASA. This paper outlines a concept to establish a NASA-level Applied Spaceflight Environments (ASE) office that will provide coordination and funding for sustained multi-program support in three technical areas that have demonstrated these needs through customer requests. These technical areas are natural environments characterization and modeling, materials and systems analysis and test, and operational space environments modeling. Additionally the ASE office will serve as an entry point of contact for external users who wish to take advantage of data and assets associated with space environments, including space weather. This paper will establish the need for the ASE, discuss a concept for organizational structure and outline the scope in the three technical areas.

EPA Collaboration with Israel

EPA Pesticide Factsheets

The United States and Israel focus on scientific and technical collaboration to protect the environment, by exchanging scientific and technical information, arranging visits of scientific personnel, cooperating in scientific symposia and workshops, etc.

The formation of floor-fractured craters in Xanthe Terra

NASA Astrophysics Data System (ADS)

Sato, Hiroyuki; Kurita, Kei; Baratoux, David

2010-05-01

Floor-fractured craters (FFC) are a peculiar form of degradation of impact craters defined by the presence of crevice networks and mesas affecting crater floors. They are preferentially distributed near chaotic terrains and outflow channels. The scope of this paper is to present a detailed systematic analysis of FFC at Xanthe Terra. FFC morphologies in this region are classified into five types making a picture of different stages of the same degradation process. FFC are geographically intermixed with un-fractured normal craters (non-FFC). Young craters are less prone to show this type of degradation, as suggested by fresh ejecta layer with preserved crater floor. Size distributions of FFC and non-FFC indicate that larger craters are preferentially fractured. Careful examinations of the crater floor elevations reveal that the crevices often extend deeper than the original crater cavity. Furthermore, an onset depth for the formation of FFC is evidenced from the difference of spatial distributions between FFC and non-FFC. Roof-collapsed depressions observed in the same region have been also documented and their characteristics suggest the removal of subsurface material at depth from about 1200 to 4000 m. These observations taken together suggest a subsurface zone of volume deficit at depth from 1 to 2 km down to several kilometers responsible for FFC formation. Then a scenario of FFC formations is presented in the context of groundwater discharge events at the late Hesperian. This scenario involves two key processes, Earth fissuring and piping erosion, known to occur with rapid groundwater migrations on Earth.

Revised methods for estimating potential reentry exposure associated with indoor crack and crevice and perimeter application.

PubMed

Driver, Jeffrey H; Ross, John H; Pandian, Muhilan; Selim, Sami; Sharp, Janice K

2013-01-01

Surface deposition of insecticides applied as indoor residential foggers, baseboard or perimeter sprays, spot sprays, and crack-and-crevice (C&C) sprays represent pathways of unintentional, postapplication exposure for children and adults. Estimation of the magnitude of this exposure following an application event is associated with uncertainty due to many factors, including (1) surface residue deposition and distribution, (2) access to and the nature of contact with treated surfaces based on time-activity patterns of residents, and (3) the role of residue removal mechanisms such as cleaning treated surfaces, pesticide degradation or redistribution, and hand washing and bathing following contact. A comparative spatial deposition study was conducted involving broadcast, perimeter, and C&C application methods. Residues measured using a spatial grid of deposition dosimeters on floor surfaces demonstrated significantly lower residue concentrations in readily accessible areas following C&C and perimeter applications, versus broadcast treatment. Analyses of other monitoring studies support this finding. The implications of these findings are discussed for both screening-level and higher tier probabilistic postapplication, residential exposure assessment. The U.S. Environmental Protection Agency (EPA) current guidance on interpretation of deposition following C&C application is supported by data in this study and others that indicate a ratio of 10:1 for deposition for broadcast versus C&C application. However, the perimeter deposition data are quite similar to C&C deposition and do not support a 70/30 default relative to broadcast recommended by the U.S. EPA (2012).

A Human Factors Analysis of Technical and Team Skills Among Surgical Trainees During Procedural Simulations in a Simulated Operating Theatre

PubMed Central

Moorthy, Krishna; Munz, Yaron; Adams, Sally; Pandey, Vikas; Darzi, Ara

2005-01-01

Background: High-risk organizations such as aviation rely on simulations for the training and assessment of technical and team performance. The aim of this study was to develop a simulated environment for surgical trainees using similar principles. Methods: A total of 27 surgical trainees carried out a simulated procedure in a Simulated Operating Theatre with a standardized OR team. Observation of OR events was carried out by an unobtrusive data collection system: clinical data recorder. Assessment of performance consisted of blinded rating of technical skills, a checklist of technical events, an assessment of communication, and a global rating of team skills by a human factors expert and trained surgical research fellows. The participants underwent a debriefing session, and the face validity of the simulated environment was evaluated. Results: While technical skills rating discriminated between surgeons according to experience (P = 0.002), there were no differences in terms of the checklist and team skills (P = 0.70). While all trainees were observed to gown/glove and handle sharps correctly, low scores were observed for some key features of communication with other team members. Low scores were obtained by the entire cohort for vigilance. Interobserver reliability was 0.90 and 0.89 for technical and team skills ratings. Conclusions: The simulated operating theatre could serve as an environment for the development of surgical competence among surgical trainees. Objective, structured, and multimodal assessment of performance during simulated procedures could serve as a basis for focused feedback during training of technical and team skills. PMID:16244534

CMMI (Trademark) for Acquisition, Version 1.2

DTIC Science & Technology

2007-11-01

conjunction with the development of the operational concept to derive more detailed and prec inclu even t . The level of detail of contractual...technical solution, different products or product components ma suppliers. idate Requirem Requirements Ana t the intended operational environment will have...Technical Solutions SP 1.1 Select Technical So SP 1.2 Analyze Selected T SP 1.3 Conduct Technical SG 2 Perform Interface Managemen SP 2.1 Select

Gun Control for VBE-E: User Guide and Technical Description

DTIC Science & Technology

2006-11-01

Defence R& D Canada – Atlantic DEFENCE DÉFENSE & Gun Control for VBE-E User Guide and Technical Description Tania E. Wentzell Technical Memorandum...Defence R& D Canada – Atlantic Technical Memorandum DRDC Atlantic TM 2006-245 November 2006 DRDC Atlantic TM 2006-245...component of the distributed experimentation environment used by the Virtual Combat System (VCS) Group at Defence R& D Canada – Atlantic (DRDC Atlantic

NASA/DOD Flight Experiments Technical Interchange Meeting Proceedings

NASA Technical Reports Server (NTRS)

1992-01-01

This document contains the proceedings of the Flight Experiments Technical Interchange Meeting held in Monterey California, October 5-9, 1992. Technical sessions 4 through 8 addressing space structures, propulsion, space power systems, space environments and effects, and space operations are covered. Many of the papers are presented in outline and viewgraph form.

Space Shuttle Technical Conference, Part 2

NASA Technical Reports Server (NTRS)

Chaffee, Norman (Compiler)

1985-01-01

The retrospective presentation provides technical disciplinary focus in the following technical areas: (1) integrated avionics; (2) guidance, navigation, and control; (3) aerodynamics; (4) structures; (5) life support, environmental control, and crew station; (6) ground operations; (7) propulsion and power; (8) communications and tracking; (9) mechanics and mechanical systems; and (10) thermal and contamination environments and protection systems.

Holocene seasonal variability inferred from multiple proxy records from Crevice Lake, Yellowstone National Park, USA

USGS Publications Warehouse

Whitlock, Cathy; Dean, Walter E.; Fritz, Sherilyn C.; Stevens, Lora R.; Stone, Jeffery R.; Power, Mitchell J.; Rosenbaum, Joseph R.; Pierce, Kenneth L.; Bracht-Flyr, Brandi B.

2012-01-01

A 9400-yr-old record from Crevice Lake, a semi-closed alkaline lake in northern Yellowstone National Park, was analyzed for pollen, charcoal, geochemistry, mineralogy, diatoms, and stable isotopes to develop a nuanced understanding of Holocene environmental history in a region of northern Rocky Mountains that receives both summer and winter precipitation. The limited surface area, conical bathymetry, and deep water (> 31 m) of Crevice Lake create oxygen-deficient conditions in the hypolimnion and preserve annually laminated sediment (varves) for much of the record. Pollen data indicate that the watershed supported a closed Pinus-dominated forest and low fire frequency prior to 8200 cal yr BP, followed by open parkland until 2600 cal yr BP, and open mixed-conifer forest thereafter. Fire activity shifted from infrequent stand-replacing fires initially to frequent surface fires in the middle Holocene and stand-replacing events in recent centuries. Low values of δ18O suggest high winter precipitation in the early Holocene, followed by steadily drier conditions after 8500 cal yr BP. Carbonate-rich sediments before 5000 cal yr BP imply warmer summer conditions than after 5000 cal yr BP. High values of molybdenum (Mo), uranium (U), and sulfur (S) indicate anoxic bottom-waters before 8000 cal yr BP, between 4400 and 3900 cal yr BP, and after 2400 cal yr BP. The diatom record indicates extensive water-column mixing in spring and early summer through much of the Holocene, but a period between 2200 and 800 cal yr BP had strong summer stratification, phosphate limitation, and oxygen-deficient bottom waters. Together, the proxy data suggest wet winters, protracted springs, and warm effectively wet summers in the early Holocene and less snowpack, cool springs, warm dry summers in the middle Holocene. In the late Holocene, the region and lake experienced extreme changes in winter, spring, and summer conditions, with particularly short springs and dry summers and winters during the Roman Warm Period (~ 2000 cal yr BP) and Medieval Climate Anomaly (1200–800 cal yr BP). Long springs and mild summers occurred during the Little Ice Age, and these conditions persist to the present. Although the proxy data indicate effectively wet summer conditions in the early Holocene and drier conditions in the middle and late Holocene, none point specifically to changes in summer precipitation as the cause. Instead, summer conditions were governed by multi-seasonal controls on effective moisture that operated over multiple time scales.

Tactical and operational response to major incidents: feasibility and reliability of skills assessment using novel virtual environments.

PubMed

Cohen, Daniel; Sevdalis, Nick; Patel, Vishal; Taylor, Michael; Lee, Henry; Vokes, Mick; Heys, Mick; Taylor, David; Batrick, Nicola; Darzi, Ara

2013-07-01

To determine feasibility and reliability of skills assessment in a multi-agency, triple-site major incident response exercise carried out in a virtual world environment. Skills assessment was carried out across three scenarios. The pre-hospital scenario required paramedics to triage and treat casualties at the site of an explosion. Technical skills assessment forms were developed using training syllabus competencies and national guidelines identified by pre-hospital response experts. Non-technical skills were assessed using a seven-point scale previously developed for use by pre-hospital paramedics. The two in-hospital scenarios, focusing on a trauma team leader and a silver/clinical major incident co-ordinator, utilised the validated Trauma-NOTECHS scale to assess five domains of performance. Technical competencies were assessed using an ATLS-style competency scale for the trauma scenario. For the silver scenario, the assessment document was developed using competencies described from a similar role description in a real-life hospital major incident plan. The technical and non-technical performance of all participants was assessed live by two experts in each of the three scenarios and inter-assessor reliability was computed. Participants also self-assessed their performance using identical proformas immediately after the scenarios were completed. Self and expert assessments were correlated (assessment cross-validation). Twenty-three participants underwent all scenarios and assessments. Performance assessments were feasible for both experts as well as the participants. Non-technical performance was generally scored higher than technical performance. Very good inter-rater reliability was obtained between expert raters across all scenarios and both technical and non-technical aspects of performance (reliability range 0.59-0.90, Ps<0.01). Significant positive correlations were found between self and expert assessment in technical skills across all three scenarios (correlation range 0.52-0.84, Ps<0.05), although no such correlations were observed in non-technical skills. This study establishes feasibility and reliability of virtual environment technical and non-technical skills assessment in major incident scenarios for the first time. The development for further scenarios and validated assessment scales will enable major incident planners to utilise virtual technologies for improved major incident preparation and training. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Policy Environments That Draw Manufacturers and Create Jobs | State, Local,

Science.gov Websites

and Tribal Governments | NREL Policy Environments That Draw Manufacturers and Create Jobs Policy Environments That Draw Manufacturers and Create Jobs The Solar Technical Assistance Team (STAT

Minnesota Custom Training: Who Is Being Served and What Role Does Custom Training Play in the Work Environment? Findings from the Minnesota Work Environment Pilot Survey.

ERIC Educational Resources Information Center

Minnesota State Technical Coll. System, St. Paul.

For the past 8 years, Minnesota technical colleges have been offering customized training services to the state's employers. To gather data on what kinds of organizations use custom training (CT) programs, the State Board of Technical Colleges surveyed 600 public and private employers that had used CT services through at least one of the system's…

Enhancement Of Water-Jet Stripping Of Foam

NASA Technical Reports Server (NTRS)

Cosby, Steven A.; Shockney, Charles H.; Bates, Keith E.; Shalala, John P.; Daniels, Larry S.

1995-01-01

Improved robotic high-pressure-water-jet system strips foam insulation from parts without removing adjacent coating materials like paints, primers, and sealants. Even injects water into crevices and blind holes to clean out foam, without harming adjacent areas. Eliminates both cost of full stripping and recoating and problem of disposing of toxic solutions used in preparation for coating. Developed for postflight refurbishing of aft skirts of booster rockets. System includes six-axis robot provided with special end effector and specially written control software, called Aftfoam. Adaptable to cleaning and stripping in other industrial settings.

Ozone Layer Research and Technical Resources

EPA Pesticide Factsheets

Access information on research and technical resources related to ozone layer science. This page provides links to research efforts led by organizations such as the National Oceanic and Atmospheric Administration, the United Nations Environment Program, an

The Relationship Between Technical And Nontechnical Skills Within A Simulation-Based Ureteroscopy Training Environment.

PubMed

Brunckhorst, Oliver; Shahid, Shahab; Aydin, Abdullatif; Khan, Shahid; McIlhenny, Craig; Brewin, James; Sahai, Arun; Bello, Fernando; Kneebone, Roger; Shamim Khan, Muhammad; Dasgupta, Prokar; Ahmed, Kamran

2015-01-01

Little integration of technical and nontechnical skills (e.g., situational awareness, communication, decision making, teamwork, and leadership) teaching exists within surgery. We therefore aimed to (1) evaluate the relationship between these 2 skill sets within a simulation-based environment and (2) assess if certain nontechnical skill components are of particular relevance to technical performance. A prospective analysis of data acquired from a comparative study of simulation vs nonsimulation training was conducted. Half of the participants underwent training of technical and nontechnical skills within ureteroscopy, with the remaining half undergoing no training. All were assessed within a full immersion environment against both technical (time to completion, Objective Structured Assessment of Technical Skills, and task-specific checklist scores) and nontechnical parameters (Nontechnical Skills for Surgeons [NOTSS] rating scale). The data of whole and individual cohorts were analyzed using Pearson correlation coefficient. The trial took place within the Simulation and Interactive Learning Centre at Guy's Hospital, London, UK. In total, 32 novice participants with no prior practical ureteroscopy experience were included within the data analysis. A correlation was found within all outcome measures analyzed. For the whole cohort, a strong negative correlation was found between time to completion and NOTSS scores (r = -0.75, p < 0.001), with strong positive correlations identified when NOTSS scores were compared with Objective Structured Assessment of Technical Skills (r = 0.89, p < 0.001) and task-specific checklist scores (r = 0.91, p < 0.001). Similar results were observed when each cohort was analyzed separately. Finally, all individual nontechnical skill components demonstrated a strong correlation with all technical skill parameters, regardless of training. A strong correlation between technical and nontechnical performance exists, which was demonstrated to be irrespective of training received. This may suggest an inherent link between skill sets. Furthermore, all nontechnical skill sets are important in technical performance. This supports the notion that both of these skills should be trained and assessed together within 1 curriculum. Copyright © 2015 Association of Program Directors in Surgery. Published by Elsevier Inc. All rights reserved.

Seasonal patterns in body temperature of free-living rock hyrax (Procavia capensis).

PubMed

Brown, Kelly J; Downs, Colleen T

2006-01-01

Rock hyrax (Procavia capensis) are faced with large daily fluctuations in ambient temperature during summer and winter. In this study, peritoneal body temperature of free-living rock hyrax was investigated. During winter, when low ambient temperatures and food supply prevail, rock hyrax maintained a lower core body temperature relative to summer. In winter body temperatures during the day were more variable than at night. This daytime variability is likely a result of body temperatures being raised from basking in the sun. Body temperatures recorded during winter never fell to low levels recorded in previous laboratory studies. During summer ambient temperatures exceeded the thermoneutral zone of the rock hyrax throughout most of the day, while crevice temperatures remained within the thermoneutral zone of rock hyrax. However, in summer variation in core body temperature was small. Minimum and maximum body temperatures did not coincide with minimum and maximum ambient temperatures. Constant body temperatures were also recorded when ambient temperatures reached lethal limits. During summer it is likely that rock hyrax select cooler refugia to escape lethal temperatures and to prevent excessive water loss. Body temperature of rock hyrax recorded in this study reflects the adaptability of this animal to the wide range of ambient temperatures experienced in its natural environment.

Susceptibility of nitinol to localized corrosion.

PubMed

Pound, Bruce G

2006-04-01

The effect of different conditions on the susceptibility of nitinol to localized corrosion was examined using the cyclic potentiodynamic polarization technique. Tests were performed on mechanically polished (MP) and electropolished (EP) nitinol wire in 0.9 wt % NaCl and phosphate-buffered saline (PBS). A polarization curve was also obtained for an EP stent in the NaCl. Differences between the breakdown potential and the corrosion potential (E(corr)) and between the protection potential and E(corr) were used to evaluate the susceptibility to pitting corrosion and crevice corrosion, respectively. The type of solution and, particularly, the surface condition affected the resistance of nitinol to pitting corrosion. Both EP and MP nitinol were more susceptible to breakdown in the NaCl than in PBS, indicating that the NaCl provides a more severe test environment than does PBS. Electropolishing increased the breakdown resistance of nitinol in PBS and the NaCl, as found in previous studies with Hank's solution. Surface condition, however, did not have a significant effect on the repassivation behavior of nitinol, as is also the case with titanium. The EP wire and stent showed similar breakdown and repassivation behavior in the NaCl, suggesting that the nature of the EP surface was similar in both cases. (c) 2005 Wiley Periodicals, Inc.

Multi-Constituent Simulation of Thrombus Deposition

NASA Astrophysics Data System (ADS)

Wu, Wei-Tao; Jamiolkowski, Megan A.; Wagner, William R.; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F.

2017-02-01

In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices.

Effects of simulated inflammation on the corrosion of 316L stainless steel.

PubMed

Brooks, Emily K; Brooks, Richard P; Ehrensberger, Mark T

2017-02-01

Stainless steel alloys, including 316L, find use in orthopaedics, commonly as fracture fixation devices. Invasive procedures involved in the placement of these devices will provoke a local inflammatory response that produces hydrogen peroxide (H 2 O 2 ) and an acidic environment surrounding the implant. This study assessed the influence of a simulated inflammatory response on the corrosion of 316L stainless steel. Samples were immersed in an electrolyte representing either normal or inflammatory physiological conditions. After 24h of exposure, electrochemical impedance spectroscopy (EIS) and inductively coupled plasma mass spectroscopy (ICPMS) were used to evaluate differences in corrosion behavior and ion release induced by the inflammatory conditions. Scanning electron microscopy (SEM) and energy-dispersive x-ray spectroscopy (EDX) were used to evaluate surface morphology and corrosion products formed on the sample surface. Inflammatory conditions, involving the presence of H 2 O 2 and an acidic pH, significantly alter the corrosion processes of 316L stainless steel, promoting aggressive and localized corrosion. It is demonstrated that particular consideration should be given to 316L stainless steel implants with crevice susceptible areas (ex. screw-head/plate interface), as those areas may have an increased probability of rapid and aggressive corrosion when exposed to inflammatory conditions. Copyright © 2016 Elsevier B.V. All rights reserved.

Femtosecond studies of protein-ligand hydrophobic binding and dynamics: human serum albumin.

PubMed

Zhong, D; Douhal, A; Zewail, A H

2000-12-19

In this contribution, we report studies of the nature of the dynamics and hydrophobic binding in protein-ligand complexes of human serum albumin with 2-(2'-hydroxyphenyl)-4-methyloxazole. With femtosecond time resolution, we examined the orientational motion of the ligand, its intrinsic nuclear motions, and the lifetime changes in the hydrophobic phase. For comparisons, with similar but chemical nanocavities, we also studied the same ligand in micelles and cyclodextrins. The hydrophobic interactions in the binding crevice are much stronger than those observed in cyclodextrins and micelles. The confined geometry restrains the nonradiative decay and significantly lengthens the excited-state lifetime. The observed dynamics over the femtosecond-to-nanosecond time scale indicate that the binding structure is rigid and the local motions of the ligand are nearly "frozen" in the protein. Another major finding is the elucidation of the directed dynamics by the protein. Proton transfer and intramolecular twisting of 2-(2'-hydroxyphenyl)-4-methyloxazole were observed to evolve along two routes: one involves the direct stretching motion in the molecular plane (approximately 200 fs) and is not sensitive to the environment; the second, less dominant, is related to the twisting motion (approximately 3 ps) of the two heterocyclic rings and drastically slows down in the protein hydrophobic pocket.

Multi-Constituent Simulation of Thrombus Deposition

PubMed Central

Wu, Wei-Tao; Jamiolkowski, Megan A.; Wagner, William R.; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F.

2017-01-01

In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices. PMID:28218279

Multi-Constituent Simulation of Thrombus Deposition.

PubMed

Wu, Wei-Tao; Jamiolkowski, Megan A; Wagner, William R; Aubry, Nadine; Massoudi, Mehrdad; Antaki, James F

2017-02-20

In this paper, we present a spatio-temporal mathematical model for simulating the formation and growth of a thrombus. Blood is treated as a multi-constituent mixture comprised of a linear fluid phase and a thrombus (solid) phase. The transport and reactions of 10 chemical and biological species are incorporated using a system of coupled convection-reaction-diffusion (CRD) equations to represent three processes in thrombus formation: initiation, propagation and stabilization. Computational fluid dynamic (CFD) simulations using the libraries of OpenFOAM were performed for two illustrative benchmark problems: in vivo thrombus growth in an injured blood vessel and in vitro thrombus deposition in micro-channels (1.5 mm × 1.6 mm × 0.1 mm) with small crevices (125 μm × 75 μm and 125 μm × 137 μm). For both problems, the simulated thrombus deposition agreed very well with experimental observations, both spatially and temporally. Based on the success with these two benchmark problems, which have very different flow conditions and biological environments, we believe that the current model will provide useful insight into the genesis of thrombosis in blood-wetted devices, and provide a tool for the design of less thrombogenic devices.

Phylogeographical patterns of an alpine plant, Rhodiola dumulosa (Crassulaceae), inferred from chloroplast DNA sequences.

PubMed

Hou, Yan; Lou, Anru

2014-01-01

The phylogeographical patterns of Rhodiola dumulosa, an alpine plant species restrictedly growing in the crevices of rock piles, were investigated based on 4 fragments of the chloroplast genome. To cover the full distribution of R. dumulosa in China, 19 populations from 3 major disjunct distribution areas (northern, central, and northwestern China) were sampled. A total of 5881bp (after alignment) of chloroplast DNA (cpDNA) from 100 individuals were sequenced. The combined cpDNA data set yielded 36 haplotypes. The total genetic diversity of R. dumulosa was remarkably high (H(T) = 0.981). The interpopulation genetic differentiation was significantly large (F(ST) = 0.8537, P < 0.001), possibly due to the long-term isolation of the natural populations. N(ST) was significantly larger than G(ST) (P < 0.001), indicating the presence of phylogeographical structure among the R. dumulosa populations. We propose 2 migration steps to explain the current distribution of R. dumulosa in China. First, this species migrated from refugia in the Qinghai-Tibetan Plateau to northern areas via the intervening highlands when temperatures increased; second, the highland populations migrated toward the mountaintops when temperatures increased further because R. dumulosa is adapted to cold environments. During the second migration step, the common ancestral haplotypes may have been gradually lost.

Terrestrial Environment (Climatic) Criteria Handbook for Use in Aerospace Vehicle Development

NASA Technical Reports Server (NTRS)

Johnson, Dale L.; Vaughan, William W.

2004-01-01

Aerospace Meteorology provides the identification of that aspect of meteorology that is concerned with the definition and modeling of atmospheric parameters for use in aerospace vehicle development, mission planning and operational capability assessments. One of the principal sources of this information is the NASA-HDBK-1001 "Terrestrial Environment (Climatic) Criteria Handbook for Use in Aerospace Vehicle Development'. This handbook was approved by the NASA Chief Engineer in 2000 as a NASA Preferred Technical Standard . Its technical contents were based on natural environment statistics/models and criteria developed mostly in the early 1990's. A task was approved to completely update the handbook to reflect the current state-of-the-art in the various terrestrial environment climatic areas.

Mars Transportation Environment Definition Document

NASA Technical Reports Server (NTRS)

Alexander, M. (Editor)

2001-01-01

This document provides a compilation of environments knowledge about the planet Mars. Information is divided into three catagories: (1) interplanetary space environments (environments required by the technical community to travel to and from Mars); (2) atmospheric environments (environments needed to aerocapture, aerobrake, or use aeroassist for precision trajectories down to the surface); and (3) surface environments (environments needed to have robots or explorers survive and work on the surface).

Examination of Faculty Expectations of Technical College Administrators as an Important Factor in High Performing Environments

ERIC Educational Resources Information Center

Dupuis, Phyllis A.

2009-01-01

Popular thought supports the notion that faculty expectations of technical college administrators appear to be linked to the success or failure of an institution at accomplishing its mission. These expectations provide the basis for the development of relationships that foster the growth of technical training and thus the growth of a skilled…

Heterogeneous Embedded Real-Time Systems Environment

DTIC Science & Technology

2003-12-01

AFRL-IF-RS-TR-2003-290 Final Technical Report December 2003 HETEROGENEOUS EMBEDDED REAL - TIME SYSTEMS ENVIRONMENT Integrated...HETEROGENEOUS EMBEDDED REAL - TIME SYSTEMS ENVIRONMENT 6. AUTHOR(S) Cosmo Castellano and James Graham 5. FUNDING NUMBERS C - F30602-97-C-0259

The Natural Hospital Environment: a Socio-Technical-Material perspective.

PubMed

Fernando, Juanita; Dawson, Linda

2014-02-01

This paper introduces two concepts into analyses of information security and hospital-based information systems-- a Socio-Technical-Material theoretical framework and the Natural Hospital Environment. The research is grounded in a review of pertinent literature with previously published Australian (Victoria) case study data to analyse the way clinicians work with privacy and security in their work. The analysis was sorted into thematic categories, providing the basis for the Natural Hospital Environment and Socio-Technical-Material framework theories discussed here. Natural Hospital Environments feature inadequate yet pervasive computer use, aural privacy shortcomings, shared workspace, meagre budgets, complex regulation that hinders training outcomes and out-dated infrastructure and are highly interruptive. Working collaboratively in many cases, participants found ways to avoid or misuse security tools, such as passwords or screensavers for patient care. Workgroup infrastructure was old, architecturally limited, haphazard in some instances, and was less useful than paper handover sheets to ensure the quality of patient care outcomes. Despite valiant efforts by some participants, they were unable to control factors influencing the privacy of patient health information in public hospital settings. Future improvements to hospital-based organisational frameworks for e-health can only be made when there is an improved understanding of the Socio-Technical-Material theoretical framework and Natural Hospital Environment contexts. Aspects within control of clinicians and administrators can be addressed directly although some others are beyond their control. An understanding and acknowledgement of these issues will benefit the management and planning of improved and secure hospital settings. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Conceptualizing the Organizational Role of Technical Communicators: A Systems Approach.

ERIC Educational Resources Information Center

Harrison, Teresa M.; Debs, Mary Beth

1988-01-01

Uses a systems approach to organizational theory to argue that technical communicators function as "boundary spanners," who make sense of and disseminate information required for coordination between organizational groups, and for effective responses to the environment. (JAD)

Corrosion resistance characteristics of a Ti-6Al-4V alloy scaffold that is fabricated by electron beam melting and selective laser melting for implantation in vivo.

PubMed

Zhao, Bingjing; Wang, Hong; Qiao, Ning; Wang, Chao; Hu, Min

2017-01-01

The purpose of this study is to determine the corrosion resistance of Ti-6Al-4V alloy fabricated with electron beam melting and selective laser melting for implantation in vivo. Ti-6Al-4V alloy specimens were fabricated with electron beam melting (EBM) and selective laser melting (SLM). A wrought form of Ti-6Al-4V alloy was used as a control. Surface morphology observation, component analysis, corrosion resistance experimental results, electrochemical impedance spectroscopy, crevice corrosion resistance experimental results, immersion test and metal ions precipitation analysis were processed, respectively. The thermal stability of EBM specimen was the worst, based on the result of open circuit potential (OCP) result. The result of electrochemical impedance spectroscopy indicated that the corrosion resistance of the SLM specimen was the best under the low electric potential. The result of potentiodynamic polarization suggested that the corrosion resistance of the SLM specimen was the best under the low electric potential (<1.5V) and EBM specimen was the best under the high electric potential (>1.5V).The crevice corrosion resistance of the EBM specimen was the best. The corrosion resistance of SLM specimen was the best, based on the result of immersion test. The content of Ti, Al and V ions of EBM, SLM and wrought specimens was very low. In general, the scaffolds that were fabricated with EBM and SLM had good corrosion resistance, and were suitable for implantation in vivo. Copyright © 2016 Elsevier B.V. All rights reserved.

Botulinum neurotoxin B recognizes its protein receptor with high affinity and specificity.

PubMed

Jin, Rongsheng; Rummel, Andreas; Binz, Thomas; Brunger, Axel T

2006-12-21

Botulinum neurotoxins (BoNTs) are produced by Clostridium botulinum and cause the neuroparalytic syndrome of botulism. With a lethal dose of 1 ng kg(-1), they pose a biological hazard to humans and a serious potential bioweapon threat. BoNTs bind with high specificity at neuromuscular junctions and they impair exocytosis of synaptic vesicles containing acetylcholine through specific proteolysis of SNAREs (soluble N-ethylmaleimide-sensitive fusion protein attachment protein receptors), which constitute part of the synaptic vesicle fusion machinery. The molecular details of the toxin-cell recognition have been elusive. Here we report the structure of a BoNT in complex with its protein receptor: the receptor-binding domain of botulinum neurotoxin serotype B (BoNT/B) bound to the luminal domain of synaptotagmin II, determined at 2.15 A resolution. On binding, a helix is induced in the luminal domain which binds to a saddle-shaped crevice on a distal tip of BoNT/B. This crevice is adjacent to the non-overlapping ganglioside-binding site of BoNT/B. Synaptotagmin II interacts with BoNT/B with nanomolar affinity, at both neutral and acidic endosomal pH. Biochemical and neuronal ex vivo studies of structure-based mutations indicate high specificity and affinity of the interaction, and high selectivity of BoNT/B among synaptotagmin I and II isoforms. Synergistic binding of both synaptotagmin and ganglioside imposes geometric restrictions on the initiation of BoNT/B translocation after endocytosis. Our results provide the basis for the rational development of preventive vaccines or inhibitors against these neurotoxins.

Electrochemical, Polarization, and Crevice Corrosion Testing of Nitinol 60, A Supplement to the ECLSS Sustaining Materials Compatibility Study

NASA Technical Reports Server (NTRS)

Lee, R. E.

2016-01-01

In earlier trials, electrochemical test results were presented for six noble metals evaluated in test solutions representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). Subsequently, a seventh metal, Nitinol 60, was added for evaluation and subjected to the same test routines, data analysis, and theoretical methodologies. The previous six test metals included three titanium grades, (commercially pure, 6Al-4V alloy and 6Al-4V low interstitial alloy), two nickel-chromium alloys (Inconel(RegisteredTrademark) 625 and Hastelloy(RegisteredTrademark) C276), and one high-tier stainless steel (Cronidur(RegisteredTrademark) 30). The three titanium alloys gave the best results of all the metals, indicating superior corrosive nobility and galvanic protection properties. For this current effort, the results have clearly shown that Nitinol 60 is almost as noble as titanium, being very corrosion-resistant and galvanically compatible with the other six metals electrochemically and during long-term exposure. is also quite noble as it is very corrosion resistant and galvanically compatible with the other six metals from both an electrochemical perspective and long-term crevice corrosion scenario. This was clearly demonstrated utilizing the same techniques for linear, Tafel and cyclic polarization, and galvanic coupling of the metal candidate as was done for the previous study. The high nobility and low corrosion susceptibility for Nitinol 60 appear to be intermediate to the nickel/chromium alloys and the titanium metals with indications that are more reflective of the titanium metals in terms of general corrosion and pitting behavior.

Mechanical Design Engineering Enabler Project wheel and wheel drives

NASA Technical Reports Server (NTRS)

Nutt, Richard E.; Couch, Britt K.; Holley, John L., Jr.; Garris, Eric S.; Staut, Paul V.

1992-01-01

Our group was assigned the responsibility of designing the wheel and wheel drive system for a proof-of-concept model of the lunar-based ENABLER. ENABLER is a multi-purpose, six wheeled vehicle designed to lift and transport heavy objects associated with the construction of a lunar base. The resulting design was based on the performance criteria of the ENABLER. The drive system was designed to enable the vehicle to achieve a speed of 7 mph on a level surface, climb a 30 percent grade, and surpass a one meter high object and one meter wide crevice. The wheel assemblies were designed to support the entire weight of the vehicle on two wheels. The wheels were designed to serve as the main component of the vehicle's suspension and will provide suitable traction for lunar-type surfaces. The expected performance of the drive system for the ENABLER was influenced by many mechanical factors. The expected top speed on a level sandy surface is 4 mph instead of the desired 7 mph. This is due to a lack of necessary power at the wheels. The lack of power resulted from dimension considerations that allowed only an eight horsepower engine and also from mechanical inefficiencies of the hydraulic system. However, the vehicle will be able to climb a 30 percent grade, surpass a one meter high object and one meter wide crevice. The wheel assemblies will be able to support the entire weight of the vehicle on two wheels. The wheels will also provide adequate suspension for the vehicle and sufficient traction for lunar-type surfaces.

Entropic depletion in colloidal suspensions and polymer liquids: Role of nanoparticle surface topography

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

Banerjee, Debapriya; Yang, Jian; Schweizer, Kenneth S.

2015-01-01

Here, we employ a hybrid Monte Carlo plus integral equation theory approach to study how dense fluids of small nanoparticles or polymer chains mediate entropic depletion interactions between topographically rough particles where all interaction potentials are hard core repulsion. The corrugated particle surfaces are composed of densely packed beads which present variable degrees of controlled topographic roughness and free volume associated with their geometric crevices. This pure entropy problem is characterized by competing ideal translational and (favorable and unfavorable) excess entropic contributions. Surface roughness generically reduces particle depletion aggregation relative to the smooth hard sphere case. However, the competition betweenmore » ideal and excess packing entropy effects in the bulk, near the particle surface and in the crevices, results in a non-monotonic variation of the particle-monomer packing correlation function as a function of the two dimensionless length scale ratios that quantify the effective surface roughness. As a result, the inter-particle potential of mean force (PMF), second virial coefficient, and spinodal miscibility volume fraction vary non-monotonically with the surface bead to monomer diameter and particle core to surface bead diameter ratios. A miscibility window is predicted corresponding to an optimum degree of surface roughness that completely destroys depletion attraction resulting in a repulsive PMF. Variation of the (dense) matrix packing fraction can enhance or suppress particle miscibility depending upon the amount of surface roughness. Connecting the monomers into polymer chains destabilizes the system via enhanced contact depletion attraction, but the non-monotonic variations with surface roughness metrics persist.« less

Feasibility study of an Integrated Program for Aerospace vehicle Design (IPAD). Volume 6: IPAD system development and operation

NASA Technical Reports Server (NTRS)

Redhed, D. D.; Tripp, L. L.; Kawaguchi, A. S.; Miller, R. E., Jr.

1973-01-01

The strategy of the IPAD implementation plan presented, proposes a three phase development of the IPAD system and technical modules, and the transfer of this capability from the development environment to the aerospace vehicle design environment. The system and technical module capabilities for each phase of development are described. The system and technical module programming languages are recommended as well as the initial host computer system hardware and operating system. The cost of developing the IPAD technology is estimated. A schedule displaying the flowtime required for each development task is given. A PERT chart gives the developmental relationships of each of the tasks and an estimate of the operational cost of the IPAD system is offered.

40 CFR 35.4195 - Are there certain people my group cannot select to be our technical advisor, grant administrator...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 1 2011-07-01 2011-07-01 false Are there certain people my group cannot select to be our technical advisor, grant administrator, or other contractor under the grant? 35... Contractor with Tag Funds § 35.4195 Are there certain people my group cannot select to be our technical...

40 CFR 35.4195 - Are there certain people my group cannot select to be our technical advisor, grant administrator...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 1 2014-07-01 2014-07-01 false Are there certain people my group cannot select to be our technical advisor, grant administrator, or other contractor under the grant? 35... Contractor with Tag Funds § 35.4195 Are there certain people my group cannot select to be our technical...

40 CFR 35.4195 - Are there certain people my group cannot select to be our technical advisor, grant administrator...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 1 2012-07-01 2012-07-01 false Are there certain people my group cannot select to be our technical advisor, grant administrator, or other contractor under the grant? 35... Contractor with Tag Funds § 35.4195 Are there certain people my group cannot select to be our technical...

40 CFR 35.4195 - Are there certain people my group cannot select to be our technical advisor, grant administrator...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 1 2013-07-01 2013-07-01 false Are there certain people my group cannot select to be our technical advisor, grant administrator, or other contractor under the grant? 35... Contractor with Tag Funds § 35.4195 Are there certain people my group cannot select to be our technical...

Micromorphology of two prehistoric ritual burials from Yemen, and considerations on methodological aspects of sampling the burial matrix - work in progress

NASA Astrophysics Data System (ADS)

Usai, Maria-Raimonda; Brothwell, Don; Buckley, Stephen; Ai-Thour, Kalid; Canti, Matthew

2010-05-01

Introduction In the central area of Yemen, two burial sites placed high in the crevices of vertical cliff face of Cretaceous sandstone (Tawilah Group) provided evidence of human remains and yielded burial soils. Radiocarbon dating indicated c.2500-2900 years BP for the burials. In other local comparable sites the deep horizontal crevices yielded Bronze Age human remains, in exceptional state of preservation Questions: What was the nature of the burial matrix? Are other human influences superimposed on the soils derived from it? Is it simply decomposed crevice rock, scraped together at the time of burial, or the result of a more complex burial practice? Such questions are also relevant to a variety of other burials of different periods and world regions. Methods Seven matrix samples from Cliff Burials (A) Talan (Layers 4,10,12,14,18,20 and 22, from top to bottom) and (B) Shiban Kawkaban (Layer 1 and 9) were analysed with micromorphology, supplemented by SEM microprobe, X-ray diffraction, gas chromatography/mass spectrometry. Results Cliff Burial Site Talan. The presence of cholesterol was confirmed in the lower sample. The second layer contained darker earth with fibrous plant material. A hard calcareous upper capping contrasted with the other levels of matrix, and it displayed a highly birefingent material with a significant component of uric acid. The other levels had variable organic content and plant inclusions, and possibly pollen. In Layer 10, aromatic acids indicative of balsam and sugar markers suggested plant gum. Cholesterol was the major sterol in Layers 10 and 22, but whilst in Layer 10 its oxidation products were present and cholestanol was abundant as normally in soils, it was only a minor component of Layer 22 where, rather, a significant amount of coprostanol indicated faecal input, and cholesterol oxidation products were absent. Cliff Burial Site Shiban Kawkaban. Although no stratification was visible to the naked eye, variation was observed at a micromorphological level. Layer 1 included mineral, bone, plant and soil-like fragments, with leaf and woody tissue, including vascular parts and seeds. Layer 9 included plant tissue, hair, seeds and some fly puparia. Comments Layering of the burial matrix in the Yemeni burials was unexpected and the burial matrix in one case was very clearly not the result of natural soil forming processes within the rock crevice. In Burial Site A the hard upper capping contained uric acid-rich deposits embedding organic tissue. This sample could possibly represent an intentional ‘plaster layer' including plant, hair and seed fragments. The abundant cholesterol confirms an animal/human origin within the matrix of Layers 10 and 22, and the stanol and bile acid distributions unequivocally confirm a human origin, despite the lack of any physical human remains. Microprobe analysis indicated that the hard cup of Burial 1 contained K, Si, Al, Cu, Mg, S, Fe and Na with amounts fluctuating relatively to depth. No special significance can be placed on the differences. This study calls attention to a neglected aspect of burial archaeology: grave infillings can no longer be assumed to be simply the return of material removed for the burial, but may be influenced by other factors. Through micromorphology, decomposed wood, shroud or other textiles or skins and hair can be detected and, if local rituals influenced the way materials were returned into the grave, then this also deserves investigation. A new ERC-funded project (Title: "Interred with their bones", acronym: "InterArChive") tackles these issues (please see separate poster). Acknowledgments We thank Allan Hall, Brendan Keely, Trevor Dransfield, Andrea Vacca and Cagliari University

Virtual reality training for improving the skills needed for performing surgery of the ear, nose or throat.

PubMed

Piromchai, Patorn; Avery, Alex; Laopaiboon, Malinee; Kennedy, Gregor; O'Leary, Stephen

2015-09-09

Virtual reality simulation uses computer-generated imagery to present a simulated training environment for learners. This review seeks to examine whether there is evidence to support the introduction of virtual reality surgical simulation into ear, nose and throat surgical training programmes. 1. To assess whether surgeons undertaking virtual reality simulation-based training achieve surgical ('patient') outcomes that are at least as good as, or better than, those achieved through conventional training methods.2. To assess whether there is evidence from either the operating theatre, or from controlled (simulation centre-based) environments, that virtual reality-based surgical training leads to surgical skills that are comparable to, or better than, those achieved through conventional training. The Cochrane Ear, Nose and Throat Disorders Group (CENTDG) Trials Search Co-ordinator searched the CENTDG Trials Register; Central Register of Controlled Trials (CENTRAL 2015, Issue 6); PubMed; EMBASE; ERIC; CINAHL; Web of Science; ClinicalTrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 27 July 2015. We included all randomised controlled trials and controlled trials comparing virtual reality training and any other method of training in ear, nose or throat surgery. We used the standard methodological procedures expected by The Cochrane Collaboration. We evaluated both technical and non-technical aspects of skill competency. We included nine studies involving 210 participants. Out of these, four studies (involving 61 residents) assessed technical skills in the operating theatre (primary outcomes). Five studies (comprising 149 residents and medical students) assessed technical skills in controlled environments (secondary outcomes). The majority of the trials were at high risk of bias. We assessed the GRADE quality of evidence for most outcomes across studies as 'low'. Operating theatre environment (primary outcomes) In the operating theatre, there were no studies that examined two of three primary outcomes: real world patient outcomes and acquisition of non-technical skills. The third primary outcome (technical skills in the operating theatre) was evaluated in two studies comparing virtual reality endoscopic sinus surgery training with conventional training. In one study, psychomotor skill (which relates to operative technique or the physical co-ordination associated with instrument handling) was assessed on a 10-point scale. A second study evaluated the procedural outcome of time-on-task. The virtual reality group performance was significantly better, with a better psychomotor score (mean difference (MD) 1.66, 95% CI 0.52 to 2.81; 10-point scale) and a shorter time taken to complete the operation (MD -5.50 minutes, 95% CI -9.97 to -1.03). Controlled training environments (secondary outcomes) In a controlled environment five studies evaluated the technical skills of surgical trainees (one study) and medical students (three studies). One study was excluded from the analysis. Surgical trainees: One study (80 participants) evaluated the technical performance of surgical trainees during temporal bone surgery, where the outcome was the quality of the final dissection. There was no difference in the end-product scores between virtual reality and cadaveric temporal bone training. Medical students: Two other studies (40 participants) evaluated technical skills achieved by medical students in the temporal bone laboratory. Learners' knowledge of the flow of the operative procedure (procedural score) was better after virtual reality than conventional training (SMD 1.11, 95% CI 0.44 to 1.79). There was also a significant difference in end-product score between the virtual reality and conventional training groups (SMD 2.60, 95% CI 1.71 to 3.49). One study (17 participants) revealed that medical students acquired anatomical knowledge (on a scale of 0 to 10) better during virtual reality than during conventional training (MD 4.3, 95% CI 2.05 to 6.55). No studies in a controlled training environment assessed non-technical skills. There is limited evidence to support the inclusion of virtual reality surgical simulation into surgical training programmes, on the basis that it can allow trainees to develop technical skills that are at least as good as those achieved through conventional training. Further investigations are required to determine whether virtual reality training is associated with better real world outcomes for patients and the development of non-technical skills. Virtual reality simulation may be considered as an additional learning tool for medical students.

In vitro simulation of fretting-corrosion in hip implant modular junctions: The influence of pH.

PubMed

Royhman, Dmitry; Patel, Megha; Jacobs, Joshua J; Wimmer, Markus A; Hallab, Nadim J; Mathew, Mathew T

2018-02-01

The fretting-corrosion behavior of mixed metal contacts is affected by various mechanical and electrochemical parameters. Crevice conditions at the junction and patient-specific pathologies can affect the pH of the prosthetic environment. The main objective of this study is to understand the effect of pH variation at the stem/head junction of the hip implant under fretting corrosion exposure. We hypothesized that pH will have a significant influence on the fretting-corrosion behavior hip implant modular junctions. A custom-made setup was used to evaluate the fretting corrosion behavior of hip implant modular junctions. A Newborn calf serum solution (30 g/L protein content) was used to simulate the synovial fluid environment. A sinusoidal fretting motion, with a displacement amplitude of +50 µm, was applied to the Ti alloy rod. The effects of pathology driven, periprosthetic pH variation were simulated at four different pH levels (3.0, 4.5, 6.0 and 7.6). Electrochemical and mechanical properties were evaluated before, during, and after the applied fretting motion. The impedance of the system was increased in response to the fretting motion. The hysteresis tangential load/displacement behavior was not affected by pH level. The worn surfaces of CoCrMo pins exhibited the presence of tribolayer or organic deposits, in the pH 4.5 group, which may explain the lower drop in potential and mass loss observed in that group. Mechanically dominated wear mechanisms, namely, adhesive wear was shown in the pH 7.6 group, which may account for a higher potential drop and metal content loss. This study suggests that the fretting-corrosion mechanisms in hip implant are affected by the pH levels of the surrounding environment and patient-specific factors. Copyright © 2017. Published by Elsevier Ltd.

Cybersecurity vulnerabilities in medical devices: a complex environment and multifaceted problem

PubMed Central

Williams, Patricia AH; Woodward, Andrew J

2015-01-01

The increased connectivity to existing computer networks has exposed medical devices to cybersecurity vulnerabilities from which they were previously shielded. For the prevention of cybersecurity incidents, it is important to recognize the complexity of the operational environment as well as to catalog the technical vulnerabilities. Cybersecurity protection is not just a technical issue; it is a richer and more intricate problem to solve. A review of the factors that contribute to such a potentially insecure environment, together with the identification of the vulnerabilities, is important for understanding why these vulnerabilities persist and what the solution space should look like. This multifaceted problem must be viewed from a systemic perspective if adequate protection is to be put in place and patient safety concerns addressed. This requires technical controls, governance, resilience measures, consolidated reporting, context expertise, regulation, and standards. It is evident that a coordinated, proactive approach to address this complex challenge is essential. In the interim, patient safety is under threat. PMID:26229513

Cybersecurity vulnerabilities in medical devices: a complex environment and multifaceted problem.

PubMed

Williams, Patricia Ah; Woodward, Andrew J

2015-01-01

The increased connectivity to existing computer networks has exposed medical devices to cybersecurity vulnerabilities from which they were previously shielded. For the prevention of cybersecurity incidents, it is important to recognize the complexity of the operational environment as well as to catalog the technical vulnerabilities. Cybersecurity protection is not just a technical issue; it is a richer and more intricate problem to solve. A review of the factors that contribute to such a potentially insecure environment, together with the identification of the vulnerabilities, is important for understanding why these vulnerabilities persist and what the solution space should look like. This multifaceted problem must be viewed from a systemic perspective if adequate protection is to be put in place and patient safety concerns addressed. This requires technical controls, governance, resilience measures, consolidated reporting, context expertise, regulation, and standards. It is evident that a coordinated, proactive approach to address this complex challenge is essential. In the interim, patient safety is under threat.

Nurses' role transition from the clinical ward environment to the critical care environment.

PubMed

Gohery, Patricia; Meaney, Teresa

2013-12-01

To explore the experiences of nurses moving from the ward environment to the critical care environment. Critical care areas are employing nurses with no critical care experience due to staff shortage. There is a paucity of literature focusing on the experiences of nurses moving from the ward environment to the critical care environment. A Heideggerian phenomenology research approach was used in this study. In-depth semi structured interviews, supported with an interview guide, were conducted with nine critical care nurses. Data analysis was guided by Van Manen (1990) approach to phenomenological analysis. Four main themes emerged: The highs and lows, you need support, theory-practice gap, struggling with fear. The participants felt ill prepared and inexperienced to work within the stressful and technical environment of critical care due to insufficient education and support. The study findings indicated that a variety of feelings and emotions are experienced by ward nurses who move into the stressful and technical environment of critical care due to insufficient skills and knowledge. More education and support is required to improve this transition process. Copyright © 2013 Elsevier Ltd. All rights reserved.

7 CFR 658.6 - Technical assistance.

Code of Federal Regulations, 2013 CFR

2013-01-01

... Secretary for Natural Resources and Environment, Office of the Secretary, Department of Agriculture... 7 Agriculture 6 2013-01-01 2013-01-01 false Technical assistance. 658.6 Section 658.6 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF...

7 CFR 658.6 - Technical assistance.

Code of Federal Regulations, 2014 CFR

2014-01-01

... Secretary for Natural Resources and Environment, Office of the Secretary, Department of Agriculture... 7 Agriculture 6 2014-01-01 2014-01-01 false Technical assistance. 658.6 Section 658.6 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF...

7 CFR 658.6 - Technical assistance.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Secretary for Natural Resources and Environment, Office of the Secretary, Department of Agriculture... 7 Agriculture 6 2011-01-01 2011-01-01 false Technical assistance. 658.6 Section 658.6 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF...

7 CFR 658.6 - Technical assistance.

Code of Federal Regulations, 2012 CFR

2012-01-01

... Secretary for Natural Resources and Environment, Office of the Secretary, Department of Agriculture... 7 Agriculture 6 2012-01-01 2012-01-01 false Technical assistance. 658.6 Section 658.6 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF...

7 CFR 658.6 - Technical assistance.

Code of Federal Regulations, 2010 CFR

2010-01-01

... Secretary for Natural Resources and Environment, Office of the Secretary, Department of Agriculture... 7 Agriculture 6 2010-01-01 2010-01-01 false Technical assistance. 658.6 Section 658.6 Agriculture Regulations of the Department of Agriculture (Continued) NATURAL RESOURCES CONSERVATION SERVICE, DEPARTMENT OF...

The Role of Passive Film Growth Kinetics and Properties in Stress Corrosion and Crevice Corrosion Susceptibility

DTIC Science & Technology

1975-10-01

Kleinzack-Mathieu Cl. Mertens, J. Meunier, Cl. Vanlengenhaghe, L. de Munck, L. Laureys , L. N. Nellmans, and M . Warzu, Corrosion Science, 3, 239 (1963). 10) H...312O448 DEPARTMENT OF COMMERCE 11. CoMfact/Grat No. WASHINGTON. D.C. 20234 M 1 mRO36-082 12. Spoasoring Organizstion N~me and Complete Address (Street...Ill. Undw Swnay Dr. 111"y Alu-Juhws. AsnluaM ScWaty fr Salome and T0e@* M /WY NATIONAL UMAU OF STANDAWS. Ernest Ambler. Acting Dimwt PART I (To be

Selectable-Tip Corrosion-Testing Electrochemical Cell

NASA Technical Reports Server (NTRS)

Lomness, Janice; Hintze, Paul

2008-01-01

The figure depicts aspects of an electrochemical cell for pitting- corrosion tests of material specimens. The cell is designed to generate a region of corrosion having a pit diameter determined by the diameter of a selectable tip. The average depth of corrosion is controlled by controlling the total electric charge passing through the cell in a test. The cell is also designed to produce minimal artifacts associated with crevice corrosion. There are three selectable tips, having diameters of 0.1 in. (0.254 cm), 0.3 in. (0.762 cm), and 0.6 in. (1.524 cm), respectively.

Performance and combustion characteristics of direct-injection stratified-charge rotary engines

NASA Technical Reports Server (NTRS)

Nguyen, Hung Lee

1987-01-01

Computer simulations of the direct-injection stratified-charge (DISC) Wankel engine have been used to calculate heat release rates and performance and efficiency characteristics of the 1007R engine. Engine pressure data have been used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine performance data are compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the Wankel engine with faster combustion, reduced leakage, higher compression ratio, and turbocharging is presented.

On the application potential of gold nanoparticles in nanoelectronics and biomedicine.

PubMed

Homberger, Melanie; Simon, Ulrich

2010-03-28

Ligand-stabilized gold nanoparticles (AuNPs) are of high interest to research dedicated to future technologies such as nanoelectronics or biomedical applications. This research interest arises from the unique size-dependent properties such as surface plasmon resonance or Coulomb charging effects. It is shown here how the unique properties of individual AuNPs and AuNP assemblies can be used to create new functional materials for applications in a technical or biological environment. While the term technical environment focuses on the potential use of AuNPs as subunits in nanoelectronic devices, the term biological environment addresses issues of toxicity and novel concepts of controlling biomolecular reactions on the surface of AuNPs.

Widening the adoption of workflows to include human and human-machine scientific processes

NASA Astrophysics Data System (ADS)

Salayandia, L.; Pinheiro da Silva, P.; Gates, A. Q.

2010-12-01

Scientific workflows capture knowledge in the form of technical recipes to access and manipulate data that help scientists manage and reuse established expertise to conduct their work. Libraries of scientific workflows are being created in particular fields, e.g., Bioinformatics, where combined with cyber-infrastructure environments that provide on-demand access to data and tools, result in powerful workbenches for scientists of those communities. The focus in these particular fields, however, has been more on automating rather than documenting scientific processes. As a result, technical barriers have impeded a wider adoption of scientific workflows by scientific communities that do not rely as heavily on cyber-infrastructure and computing environments. Semantic Abstract Workflows (SAWs) are introduced to widen the applicability of workflows as a tool to document scientific recipes or processes. SAWs intend to capture a scientists’ perspective about the process of how she or he would collect, filter, curate, and manipulate data to create the artifacts that are relevant to her/his work. In contrast, scientific workflows describe the process from the point of view of how technical methods and tools are used to conduct the work. By focusing on a higher level of abstraction that is closer to a scientist’s understanding, SAWs effectively capture the controlled vocabularies that reflect a particular scientific community, as well as the types of datasets and methods used in a particular domain. From there on, SAWs provide the flexibility to adapt to different environments to carry out the recipes or processes. These environments range from manual fieldwork to highly technical cyber-infrastructure environments, i.e., such as those already supported by scientific workflows. Two cases, one from Environmental Science and another from Geophysics, are presented as illustrative examples.

Strategy-Based Technical Instruction: Development and Evaluation

DTIC Science & Technology

1988-08-01

scripts dependant on target tasks and the outcomes desired, and to the use of node-link knowledge maps as communications props. In addition, we have...information "on the job" - communicate with others in the task environment; - monitor, diagnose, and correct problems associated with critical tasks... communicated . Technical Training Goals The individual in a technical training scenario is expected to achieve a wide variety of goals. These goals can

From LDEF to a national Space Environment and Effects (SEE) program: A natural progression

NASA Technical Reports Server (NTRS)

Bowles, David E.; Calloway, Robert L.; Funk, Joan G.; Kinard, William H.; Levine, Arlene S.

1995-01-01

As the LDEF program draws to a close, it leaves in place the fundamental building blocks for a Space Environment and Effects (SEE) program. Results from LDEF data analyses and investigations now form a substantial core of knowledge on the long term effects of the space environment on materials, system and structures. In addition, these investigations form the basic structure of a critically-needed SEE archive and database system. An agency-wide effort is required to capture all elements of a SEE program to provide a more comprehensive and focused approach to understanding the space environment, determining the best techniques for both flight and ground-based experimentation, updating the models which predict both the environments and those effects on subsystems and spacecraft, and, finally, ensuring that this multitudinous information is properly maintained, and inserted into spacecraft design programs. Many parts and pieces of a SEE program already exist at various locations to fulfill specific needs. The primary purpose of this program, under the direction of the Office of Advanced Concepts and Technology (OACT) in NASA Headquarters, is to take advantage of these parts; apply synergisms where possible; identify and when possible fill-in gaps; coordinate and advocate a comprehensive SEE program. The SEE program must coordinate and support the efforts of well-established technical communities wherein the bulk of the work will continue to be done. The SEE program will consist of a NASA-led SEE Steering Committee, consisting of government and industry users, with the responsibility for coordination between technology developers and NASA customers; and Technical Working Groups with primary responsibility for program technical content in response to user needs. The Technical Working Groups are as follows: Materials and Processes; Plasma and Fields; Ionizing Radiation; Meteoroids and Orbital Debris; Neutral External Contamination; Thermosphere, Thermal, and Solar Conditions; Electromagnetic Effects; Integrated Assessments and Databases. Specific technology development tasks will be solicited through a NASA Research Announcement to be released in May of 1994. The areas in which tasks are solicited include: (1) engineering environment definitions, (2) environments and effects design guidelines, (3) environments and effects assessment models and databases, and (4) flight/ground simulation/technology assessment data.

From LDEF to a national Space Environment and Effects (SEE) program: A natural progression

NASA Astrophysics Data System (ADS)

Bowles, David E.; Calloway, Robert L.; Funk, Joan G.; Kinard, William H.; Levine, Arlene S.

1995-02-01

As the LDEF program draws to a close, it leaves in place the fundamental building blocks for a Space Environment and Effects (SEE) program. Results from LDEF data analyses and investigations now form a substantial core of knowledge on the long term effects of the space environment on materials, system and structures. In addition, these investigations form the basic structure of a critically-needed SEE archive and database system. An agency-wide effort is required to capture all elements of a SEE program to provide a more comprehensive and focused approach to understanding the space environment, determining the best techniques for both flight and ground-based experimentation, updating the models which predict both the environments and those effects on subsystems and spacecraft, and, finally, ensuring that this multitudinous information is properly maintained, and inserted into spacecraft design programs. Many parts and pieces of a SEE program already exist at various locations to fulfill specific needs. The primary purpose of this program, under the direction of the Office of Advanced Concepts and Technology (OACT) in NASA Headquarters, is to take advantage of these parts; apply synergisms where possible; identify and when possible fill-in gaps; coordinate and advocate a comprehensive SEE program. The SEE program must coordinate and support the efforts of well-established technical communities wherein the bulk of the work will continue to be done. The SEE program will consist of a NASA-led SEE Steering Committee, consisting of government and industry users, with the responsibility for coordination between technology developers and NASA customers; and Technical Working Groups with primary responsibility for program technical content in response to user needs. The Technical Working Groups are as follows: Materials and Processes; Plasma and Fields; Ionizing Radiation; Meteoroids and Orbital Debris; Neutral External Contamination; Thermosphere, Thermal, and Solar Conditions; Electromagnetic Effects; Integrated Assessments and Databases. Specific technology development tasks will be solicited through a NASA Research Announcement to be released in May of 1994. The areas in which tasks are solicited include: (1) engineering environment definitions, (2) environments and effects design guidelines, (3) environments and effects assessment models and databases, and (4) flight/ground simulation/technology assessment data.

A technical platform for environments for ageing--lessons learned from three field studies.

PubMed

Eichelberg, Marco; Büsching, Felix; Steen, Enno-Edzard; Helmer, Axel; Thiel, Andreas; Hein, Andreas; Wolf, Lars

2014-01-01

The Lower Saxony Research Network "Design of Environments for Ageing" (GAL) studied possible applications of assistive technology for enabling older adults to live longer and independent in their own home. As part of this work, a technical platform was developed as a common technical basis for all assistive systems in the project. This article presents an overview of the architecture and core functionality of the technical platform, which in the first generation was developed for use in a laboratory setting, and in a second generation was extended for use in the project's field studies, i.e. prototype installations in end-users homes. The field studies' primary objective was the evaluation of the assistive technologies, that were developed within the overall project. However, these studies also confirmed that the fundamental concept of the technical platform is valid, and the prototypes continuously worked 24 h a day for several months. However, there were some problems related to lack of infrastructure in the older adults' homes and human factors such as inadvertent placement of objects across sensors' field of view, acceptance problems due to aesthetical reasons or simply communication problems, which show that making complex technologies work for users with little technical experience is well possible, but requires a careful consideration of the complete service chain and related "soft factors".

Book review of Littler DM. Littler MM (2000) Caribbean Reef Plants An Identification Guide to the Reef Plants of the Caribbean, Bahamas, Florida and Gulf of Mexico

NASA Astrophysics Data System (ADS)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

Molluscan assemblages on coral reefs and associated hard substrata in the northern Red Sea

NASA Astrophysics Data System (ADS)

Zuschin, M.; Hohenegger, J.; Steininger, F.

2001-09-01

Information on spatial variability and distribution patterns of organisms in coral reef environments is necessary to evaluate the increasing anthropogenic disturbance of marine environments (Richmond 1993; Wilkinson 1993; Dayton 1994). Therefore different types of subtidal, reef-associated hard substrata (reef flats, reef slopes, coral carpets, coral patches, rock grounds), each with different coral associations, were investigated to determine the distribution pattern of molluscs and their life habits (feeding strategies and substrate relations). The molluscs were strongly dominated by taxa with distinct relations to corals, and five assemblages were differentiated. The Dendropoma maxima assemblage on reef flats is a discrete entity, strongly dominated by this encrusting and suspension-feeding gastropod. All other assemblages are arranged along a substrate gradient of changing coral associations and potential molluscan habitats. The Coralliophila neritoidea- Barbatia foliata assemblage depends on the presence of Porites and shows a dominance of gastropods feeding on corals and of bivalves associated with living corals. The Chamoidea- Cerithium spp. assemblage on rock grounds is strongly dominated by encrusting bivalves. The Drupella cornus-Pteriidae assemblage occurs on Millepora- Acropora reef slopes and is strongly dominated by bivalves associated with living corals. The Barbatia setigera- Ctenoides annulata assemblage includes a broad variety of taxa, molluscan life habits and bottom types, but occurs mainly on faviid carpets and is transitional among the other three assemblages. A predicted degradation of coral coverage to rock bottoms due to increasing eutrophication and physical damage in the study area (Riegl and Piller 2000) will result in a loss of coral-associated molluscs in favor of bivalve crevice dwellers in dead coral heads and of encrusters on dead hard substrata.

NASA Environmentally Responsible Aviation's Highly-Loaded Front Block Compressor Demonstration

NASA Technical Reports Server (NTRS)

Celestina, Mark

2017-01-01

The ERA project was created in 2009 as part of NASAs Aeronautics Research Mission Directorates (ARMD) Integrated Systems Aviation Program (IASP). The purpose of the ERA project was to explore and document the feasibility, benefit, and technical risk of vehicles concepts and enabling technologies to reduce aviations impact on the environment. The metrics for this technology is given in Figure 1 with the N+2 metrics highlighted in green. It is anticipated that the United States air transportation system will continue to expand significantly over the next few decades thus adversely impacting the environment unless new technology is incorporated to simultaneously reduce nitrous oxides (NOx), noise and fuel consumption. In order to achieve the overall goals and meet the technology insertion challenges, these goals were divided into technical challenges that were to be achieved during the execution of the ERA project. Technical challenges were accomplished through test campaigns conducted by Integrated Technology Demonstration (ITDs). ERAs technical performance period ended in 2015.

Terahertz (THz) Radar: A Solution for Degraded Visibility Environments (DVE)

DTIC Science & Technology

2016-11-01

TECHNICAL REPORT RDMR-WD-16-49 TERAHERTZ (THZ) RADAR: A SOLUTION FOR DEGRADED VISIBILITY ENVIRONMENTS (DVE) Henry O...Terahertz (THz) Radar: A Solution For Degraded Visibility Environments (DVE) 5. FUNDING NUMBERS 6. AUTHOR(S) Henry O. Everitt...to compensate for environmental conditions, allowing for actionable images in Degraded Visibility Environments (DVE). 14. SUBJECT TERMS Radar

The Influence of Organizations on Writers' Texts and Training.

ERIC Educational Resources Information Center

Lutz, Jean

1986-01-01

Argues that, to succeed in the workplace, technical writers must supplement their knowledge of writing and rhetoric with an appreciation of "organizational culture." Explains how to do this and shows how technical writing classes can prepare students for this adjustment to the corporate environment. (FL)

78 FR 10175 - Agency Information Collection Activities: Proposed Collection; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-13

... patient or provider characteristics, physical environment and layout; technical training and support... practice, and, in particular, the technical aspects of clinicians using the health IT system. The focus...; the extent and adequacy of training or instruction patients received in using the health IT; attitudes...

Factors Affecting Training Effectiveness in Synchronous, Dispersed Virtual Environments

DTIC Science & Technology

2014-06-01

technology to its technical training programs. Specifically, a distance learning model with instruction provided through 3-D virtual worlds could...ABSTRACT The U.S. Navy is investigating the feasibility of incorporating distance learning technology to its technical training programs. Specifically...15 A. TECHNOLOGY ACCEPTANCE MODEL

Business Teachers Go to Work and Students Get the Dividends

ERIC Educational Resources Information Center

Stephens, Geralyn E.

2010-01-01

Teacher internships give business education teachers the opportunity to increase their industry skill proficiency levels. Such experiences can help business education teachers focus on developing relevant technical knowledge and skills to better prepare students for technically enhanced work environments and demonstrate competency on technical…

What's in a Name?

ERIC Educational Resources Information Center

Hoyt, Kenneth B.

When the American Vocational Association changed its name to the Association for Career and Technical Education, it underscored the need for today's vocational educators to focus on both career education and technical education. The name change reflects the fact that today's work environment, labor market, and employment opportunities are very…

Using Corporate-Based Methods To Assess Technical Communication Programs.

ERIC Educational Resources Information Center

Faber, Brenton; Bekins, Linn; Karis, Bill

2002-01-01

Investigates methods of program assessment used by corporate learning sites and profiles value added methods as a way to both construct and evaluate academic programs in technical communication. Examines and critiques assessment methods from corporate training environments including methods employed by corporate universities and value added…

Heat strain models applicable for protective clothing: Comparison of core temperature response. Technical report

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

Gonzalez, R.R.; McLellan, T.M.; Withey, W.R.

This report represents the results of TTCP-UTP6 efforts on modeling aspects when chemical protective ensembles are worn which need to be considered in warm environments. Since 1983, a significant data base has been collected using human experimental studies and wide clothing systems from which predictive modeling equations have been developed with individuals working in temperate and hot environments, but few comparisons of the -- results from various model outputs have ever been carried out. This initial comparison study was part of a key technical area (KIA) project for The Technical Cooperation Program (TTCP) UTP-6 working party. A modeling workshop wasmore » conducted in Toronto, Canada on 9-10 June 1994 to discuss the data reduction and results acquired in an initial clothing analysis study of TTCP using various chemical protective garments. To our knowledge, no comprehensive study to date has ever focused on comparing experimental results using an international standardized heat stress procedure matched to physiological outputs from various model predictions in individuals dressed in chemical protective clothing systems. This is the major focus of this TTCP key technical study. This technical report covers one aspect of the working party`s results.« less

Concentration and transport of chlordane and nonachlor associated with suspended sediment in the Mississippi River, May 1988 to June 1990

USGS Publications Warehouse

Rostad, C.E.

1997-01-01

Technical chlordane, a formerly widely used organochlorine pesticide, has become widespread in the environment. The distribution of technical chlordane in riverine environments may be due in part to resuspension and aqueous transport of contaminated bed sediment. To test this hypothesis, the Mississippi River was sampled for suspended sediment five times over a two- year period, at up to 17 sites from St. Louis to below New Orleans, including major tributaries. The ratio of chlordane to nonachlor concentrations averaged 3.6 during May-June 1988 for the Mississippi River below its confluence with the Ohio River. During March-April 1989, the ratio was 0.6, suggesting weathered technical chlordane contributions to the suspended sediment. During June 1989, the ratio averaged 1.1, indicating some input of less weathered technical chlordane. During February-March and May-June 1990, the ratios again shifted, from 0.8 to 1.3. This shifting ratio is likely due to resuspension of weathered technical chlordane associated with bed sediment during spring runoff. Annual transport by suspended sediment from the Mississippi River to the Gulf of Mexico was estimated to be 110 kg of chlordane and 100 kg of nonachlor.

EPA's 2007 Report on the Environment: Science Report (Sab Review Draft)

EPA Science Inventory

The EPA's 2007 Report on the Environment: Science Report (SAB Review Draft), formally known as the EPA's Report on the Environment - Technical Document, was released for public review and comment prior to the Science Advisory Board's (SAB) meeting and review held in July 2007. Co...

Plurigon: three dimensional visualization and classification of high-dimensionality data

PubMed Central

Martin, Bronwen; Chen, Hongyu; Daimon, Caitlin M.; Chadwick, Wayne; Siddiqui, Sana; Maudsley, Stuart

2013-01-01

High-dimensionality data is rapidly becoming the norm for biomedical sciences and many other analytical disciplines. Not only is the collection and processing time for such data becoming problematic, but it has become increasingly difficult to form a comprehensive appreciation of high-dimensionality data. Though data analysis methods for coping with multivariate data are well-documented in technical fields such as computer science, little effort is currently being expended to condense data vectors that exist beyond the realm of physical space into an easily interpretable and aesthetic form. To address this important need, we have developed Plurigon, a data visualization and classification tool for the integration of high-dimensionality visualization algorithms with a user-friendly, interactive graphical interface. Unlike existing data visualization methods, which are focused on an ensemble of data points, Plurigon places a strong emphasis upon the visualization of a single data point and its determining characteristics. Multivariate data vectors are represented in the form of a deformed sphere with a distinct topology of hills, valleys, plateaus, peaks, and crevices. The gestalt structure of the resultant Plurigon object generates an easily-appreciable model. User interaction with the Plurigon is extensive; zoom, rotation, axial and vector display, feature extraction, and anaglyph stereoscopy are currently supported. With Plurigon and its ability to analyze high-complexity data, we hope to see a unification of biomedical and computational sciences as well as practical applications in a wide array of scientific disciplines. Increased accessibility to the analysis of high-dimensionality data may increase the number of new discoveries and breakthroughs, ranging from drug screening to disease diagnosis to medical literature mining. PMID:23885241

Vapor Corrosion Response of Low Carbon Steel Exposed to Simulated High Level Radioactive Waste

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

Wiersma, B

2006-01-26

A program to resolve the issues associated with potential vapor space corrosion and liquid/air interface corrosion in the Type III high level waste tanks is in place. The objective of the program is to develop understanding of vapor space (VSC) and liquid/air interface (LAIC) corrosion to ensure a defensible technical basis to provide accurate corrosion evaluations with regard to vapor space and liquid/air interface corrosion. The results of the FY05 experiments are presented here. The experiments are an extension of the previous research on the corrosion of tank steel exposed to simple solutions to corrosion of the steel when exposedmore » to complex high level waste simulants. The testing suggested that decanting and the consequent residual species on the tank wall is the predominant source of surface chemistry on the tank wall. The laboratory testing has shown that at the boundary conditions of the chemistry control program for solutions greater than 1M NaNO{sub 3}{sup -}. Minor and isolated pitting is possible within crevices in the vapor space of the tanks that contain stagnant dilute solution for an extended period of time, specifically when residues are left on the tank wall during decanting. Liquid/air interfacial corrosion is possible in dilute stagnant solutions, particularly with high concentrations of chloride. The experimental results indicate that Tank 50 would be most susceptible to the potential for liquid/air interfacial corrosion or vapor space corrosion, with Tank 49 and 41 following, since these tanks are nearest to the chemistry control boundary conditions. The testing continues to show that the combination of well-inhibited solutions and mill-scale sufficiently protect against pitting in the Type III tanks.« less

Crystal structure of the human cytosolic sialidase Neu2. Evidence for the dynamic nature of substrate recognition.

PubMed

Chavas, Leonard M G; Tringali, Cristina; Fusi, Paola; Venerando, Bruno; Tettamanti, Guido; Kato, Ryuichi; Monti, Eugenio; Wakatsuki, Soichi

2005-01-07

Gangliosides play key roles in cell differentiation, cell-cell interactions, and transmembrane signaling. Sialidases hydrolyze sialic acids to produce asialo compounds, which is the first step of degradation processes of glycoproteins and gangliosides. Sialidase involvement has been implicated in some lysosomal storage disorders such as sialidosis and galactosialidosis. Neu2 is a recently identified human cytosolic sialidase. Here we report the first high resolution x-ray structures of mammalian sialidase, human Neu2, in its apo form and in complex with an inhibitor, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid (DANA). The structure shows the canonical six-blade beta-propeller observed in viral and bacterial sialidases with its active site in a shallow crevice. In the complex structure, the inhibitor lies in the catalytic crevice surrounded by ten amino acids. In particular, the arginine triad, conserved among sialidases, aids in the proper positioning of the carboxylate group of DANA within the active site region. The tyrosine residue, Tyr(334), conserved among mammalian and bacterial sialidases as well as in viral neuraminidases, facilitates the enzymatic reaction by stabilizing a putative carbonium ion in the transition state. The loops containing Glu(111) and the catalytic aspartate Asp(46) are disordered in the apo form but upon binding of DANA become ordered to adopt two short alpha-helices to cover the inhibitor, illustrating the dynamic nature of substrate recognition. The N-acetyl and glycerol moieties of DANA are recognized by Neu2 residues not shared by bacterial sialidases and viral neuraminidases, which can be regarded as a key structural difference for potential drug design against bacteria, influenza, and other viruses.

Biological responses of Crested and Least auklets to volcanic destruction of nesting habitat in the Aleutian Islands, Alaska

USGS Publications Warehouse

Drew, Gary S.; Piatt, John F.; Williams, Jeffrey C.

2018-01-01

Crested Auklets (Aethia cristatella) and Least Auklets (A. pusilla) are crevice-nesting birds that breed in large mixed colonies at relatively few sites in the Aleutian Island archipelago, Bering Sea, Gulf of Alaska, and Sea of Okhotsk. Many of these colonies are located on active volcanic islands. The eruption of Kasatochi volcano, in the central Aleutians, on August 7, 2008, completely buried all crevice-nesting seabird habitat on the island. This provided an opportunity to examine the response of a large, mixed auklet colony to a major geological disturbance. Time-lapse imagery of nesting habitat indicated that both species returned to the largest pre-eruption colony site for several years, but subsequently abandoned it within 5 yr after the eruption. In 2010, a rockfall site in a cove north of the old colony site began to accumulate talus, and groups of auklets were observed using the site in 2011. Use of the new colony appeared to coincide with the abandonment of the old colony site by both species, though surface counts suggested that Least Auklets shifted to the new colony sooner than Crested Auklets. At-sea surveys of seabirds before and after the eruption indicated that both Crested and Least auklets shifted their at-sea distributions from the waters around Kasatochi Island to nearby Koniuji Island. In combination, at-sea counts and colony time-lapse imagery indicated that Crested and Least auklets using Kasatochi responded to the volcanic disturbance and complete loss of nesting habitat at the main colony on Kasatochi with dispersal either to newly created habitat on Kasatochi or to an alternate colony on a nearby island.

Comparative skull anatomy of terrestrial and crevice-dwelling Trachylepis skinks (Squamata: Scincidae) with a survey of resources in scincid cranial osteology.

PubMed

Paluh, Daniel J; Bauer, Aaron M

2017-01-01

Skinks account for more than 25% of all lizard species; however, representatives of fewer than a quarter of all species have been characterized osteologically. All but a few of the available cranial descriptions concentrate solely on characters that can be seen externally on the intact skull. Mabuyid skinks of the genus Trachylepis are the dominant, fully limbed skinks in Sub-Saharan Africa, and nearly all species have the same generalized body plan. Although a few rock crevice-dwelling species possess slight body depression, extreme dorsoventral depression is observed only in Trachylepis laevis. We investigated the detailed skull anatomy of three Trachylepis skinks (T. laevis, T. sulcata, and T. gonwouoi, a recently described species allied to T. affinis) using high-resolution X-ray micro-computed tomography. Our goals were to review the scincid cranial osteology literature in a phylogenetic context, provide a detailed anatomical atlas for the mabuyid lineage, and investigate the morphological adaptations of the highly modified T. laevis. Our results demonstrate that there is significant morphological variation between these three taxa, including the loss and fusion of structures, as well as changes in the shape, scale, and relationship between individual elements. Trachylepis laevis possesses several osteological modifications that have produced a reducton in head depth that are likely functional consequences of extreme rupicolous habits, including a flat skull roof, many strongly recumbent elements, and a depressed neurocranium.We hypothesize these modifications may correspond to descreased bite force and increased capabilities of cranial kinesis. Our study is the first element-by-element description of a skink using computed tomography technology.

Total reflection X-ray fluorescence analysis of oral fluids of women affected by osteoporosis and osteopenia

NASA Astrophysics Data System (ADS)

Sánchez, Héctor Jorge; Valentinuzzi, María Cecilia; Grenón, Miram; Abraham, José

2008-12-01

Osteoporosis is a disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to bone fragility and an increased susceptibility to fractures; the early stage of decreased bone density is called osteopenia. More than 200 million people are affected and about 50% of post-menopausic women are expected to develop the disease. Osteoporosis, osteopenia and periodontal disease have in common several risk factors, being hyperthyroidism and smoking habits the most important ones. There is scarce information in the literature about the association between periodontal disease and osteoporosis and/or osteopenia. Some works suggest that osteoporotic women are susceptible to a higher loss of periodontal insertion, alveolar bones, and teeth. Thirty adult post-menopausic women were studied; some of them were healthy (control group) and the rest of them were undergoing some stage of osteoporosis or osteopenia. All the subjects were healthy, non-smokers, not having dental implants, and with communitarian periodontal index higher than 1(CPI > 1). Samples of saliva and gingival crevice fluid were extracted with calibrated micro-capillaries and deposited on Si reflectors. Known amounts of Ga were added to the samples in order to act as internal standard for quantification by the total reflection x-ray fluorescence technique. Experimental concentrations of several elements (P, S, Cl, K, Ca, Cr, Fe, NI, Cu, and Zn) were determined. The concentration of some elements in saliva showed different behavior as compared to gingival crevice fluid. Some critical elements of bone composition, such as Ca and Zn, present very distinguishable behavior. Improvements in the statistics are required for a better assessment of a routine method and to establish some correlation with periodontal disease. TXRF seems to be a promising method to evaluate the evolution of osteoporosis.

Multi-locus DNA sequence data reveal a history of deep cryptic vicariance and habitat-driven convergence in the desert night lizard Xantusia vigilis species complex (Squamata: Xantusiidae).

PubMed

Leavitt, Dean H; Bezy, Robert L; Crandall, Keith A; Sites, Jack W

2007-11-01

The lizard genus Xantusia of southwestern North America has received recent attention in relation to delimiting species. Using more than 500 lizards from 156 localities, we further test hypothesized species boundaries and clarify phylogeographical patterns, particularly in regions of potential secondary contact. We sequenced the entire mitochondrial cytochrome b gene for every lizard in the study, plus a second mitochondrial DNA (mtDNA) region and two nuclear introns for subsets of the total sample. Phylogenetic analyses of the mtDNA recover a well-resolved, novel hypothesis for species in the Xantusia vigilis complex. The nuclear DNA (nDNA) data provide independent support for the recognition of X. arizonae, X. bezyi and X. wigginsi. Differences between the respective mtDNA and nDNA topologies result from either the effects of lineage sorting or ancient introgression. Nuclear data confirm the inference that some populations of X. vigilis in northwestern Arizona converged on rock-crevice-dwelling morphology and are not X. arizonae with an introgressed X. vigilis mtDNA genome. The historical independence of ancient cryptic lineages of Xantusia in southern California is also corroborated, though limited introgression is detected. Our proposed biogeographical scenario indicates that diversification of this group was driven by vicariance beginning in the late Miocene. Additionally, Pleistocene climatical changes influenced Xantusia distribution, and the now inhospitable Colorado Desert previously supported night lizard presence. The current taxonomy of the group likely underestimates species diversity within the group, and our results collectively show that while convergence on the rock-crevice-dwelling morphology is one hallmark of Xantusia evolution, morphological stasis is paradoxically another.

Comparative skull anatomy of terrestrial and crevice-dwelling Trachylepis skinks (Squamata: Scincidae) with a survey of resources in scincid cranial osteology

PubMed Central

Bauer, Aaron M.

2017-01-01

Skinks account for more than 25% of all lizard species; however, representatives of fewer than a quarter of all species have been characterized osteologically. All but a few of the available cranial descriptions concentrate solely on characters that can be seen externally on the intact skull. Mabuyid skinks of the genus Trachylepis are the dominant, fully limbed skinks in Sub-Saharan Africa, and nearly all species have the same generalized body plan. Although a few rock crevice-dwelling species possess slight body depression, extreme dorsoventral depression is observed only in Trachylepis laevis. We investigated the detailed skull anatomy of three Trachylepis skinks (T. laevis, T. sulcata, and T. gonwouoi, a recently described species allied to T. affinis) using high-resolution X-ray micro-computed tomography. Our goals were to review the scincid cranial osteology literature in a phylogenetic context, provide a detailed anatomical atlas for the mabuyid lineage, and investigate the morphological adaptations of the highly modified T. laevis. Our results demonstrate that there is significant morphological variation between these three taxa, including the loss and fusion of structures, as well as changes in the shape, scale, and relationship between individual elements. Trachylepis laevis possesses several osteological modifications that have produced a reducton in head depth that are likely functional consequences of extreme rupicolous habits, including a flat skull roof, many strongly recumbent elements, and a depressed neurocranium.We hypothesize these modifications may correspond to descreased bite force and increased capabilities of cranial kinesis. Our study is the first element-by-element description of a skink using computed tomography technology. PMID:28902864

The distribution of chlorpyrifos following a crack and crevice type application in the US EPA Indoor Air Quality Research House

NASA Astrophysics Data System (ADS)

Stout, D. M.; Mason, M. A.

A study was conducted in the US EPA Indoor Air Quality (IAQ) Research House to determine the spatial and temporal distribution of chlorpyrifos following a professional crack and crevice application in the kitchen. Following the application, measurements were made in the kitchen, den and master bedroom over 21 days. Airborne concentrations were collected using both polyurethane foam (PUF) and the OSHA versatile sampler composed of XAD and PUF media located in tandem. Measured airborne concentrations were similar for the two samplers and were higher in the three rooms following the application. The highest measured concentrations were reached during the initial 24-h following application; concentrations subsequently declined over the 21-day study period to levels slightly above background. Spatial and temporal distributions onto surfaces were measured using 10-cm 2 rayon deposition coupons located on the floor. Sections were cut from existing carpet to determine the total extractable residues. Chlorpyrifos was measured from all matrixes in the kitchen, den and bedroom and the data shows the transport of airborne residues from the point of application to remote locations in the house. The findings are compared and discussed relative to another study conducted in which total release aerosols containing chlorpyrifos were activated in the IAQ research house and the resulting distributions evaluated. For both studies dose estimates were constructed for the exposure pathways using the Stochastic Human Exposure and Dose Estimation Model for pesticides. The United States Environmental Protection Agency has been mandated to examine children's exposure to environmental pollutants such as pesticides. This research specifically reduces uncertainties associated with estimating children's potential exposures to residentially applied pesticides and provides inputs to further evaluate and validate residential exposure models which might be used to reduce exposures and perform risk assessments.

Insight into the binding modes of Lassa nucleoprotein complexed with ssRNA by molecular dynamic simulations and free energy calculations.

PubMed

Zhang, Ying; Chen, Hang; Han, Ju-Guang

2015-01-01

Lassa virus (LASV), an arenavirus known to be responsible for a severe hemorrhagic fever, causes thousands of deaths annually and there is no effective vaccine for it so far. The nucleoprotein (NP) of LASV plays an essential role in the replication and transcription of the viral genome. Recent research shows that viral RNA binds in a deep crevice located within the N-terminal domain of NP and suggests a gating mechanism in which NP transforms from a "closed" position to an "open" position to bind RNA. To characterize the molecular mechanisms of how RNA binds to N-terminal domain of NP, two molecular dynamic (MD) simulations of RNA-binding structure and RNA-free structure have been performed. The simulation results show that an important helix α6 interacts with RNA in the "open" conformation, while helix α6 rotates toward the binding crevice and reduces the space of RNA-binding pocket in the "closed" conformation; it appears that helix α6 would clash with RNA while NP is in a "closed" state. In addition, to characterize the role of residues involved in the binding of RNA, the MD simulations of the double-mutant (W164A/F176A) and the single-mutant (G243P) RNA-binding NP complexes have been performed. Our MD simulations and molecular mechanics-generalized born surface area (MM-GBSA) energy calculations exhibit that the three mutant residues increase the binding affinity. Furthermore, we infer that the defect of the replication and transcription of viral genome is possibly due to the change of structural integrity rather than the reduction of RNA-binding affinity.

Development of sustained release antipsychotic tablets using novel polysaccharide isolated from Delonix regia seeds and its pharmacokinetic studies

PubMed Central

Krishnaraj, Kaliaperumal; Chandrasekar, Mulla Joghi Nanjan; Nanjan, Mulla Joghi; Muralidharan, Selvadurai; Manikandan, Duraikannu

2011-01-01

A natural polysaccharide was isolated from the seeds of Delonix regia. The isolated polysaccharide could maintain aqueous equilibrium between the dosage form and the surrounding medium due to its massive competence of water absorption (80.72%) and swelling index (266.7%). The Scanning Electron Micrograph of a polysaccharide exhibits rough surface with pores and crevices, hence, the drug release will be retarded because of the drug particles entrapment in the pores and crevices. Further, the surface tension of polysaccharide is higher than that of water, which may facilitate sustained release of drugs from dosage forms. An antipsychotic drug, quetiapine fumarate has a short half-life of 6 h and administered multiple times per day. Hence the quetiapine fumarate oral sustained release tablets were formulated using this polysaccharide in the concentration of 5–30% to avoid the side effects and increase patient compliance. Dissolution of the developed tablets with 25% polysaccharide content showed a better release profile than the other batches (5–20%) at the end of 12 h. The strong matrix complex has low solubility in water, it does not dissolve rapidly and the drug continues to diffuse through the gel layer at a consistent rate. Drug release from the matrix tablets follows matrix type except F-4 and F-5 which follow first order and Hix.crow type. The bioavailability study was carried out using healthy male New Zealand white rabbits that show the AUC(0–inf) value for developed SR tablets is 1.44 times higher than the reference thus, indicating more efficient and sustained drug delivery capable of maintaining plasma drug levels better. PMID:24115903

Surprising Beauty in Technical Photography

ERIC Educational Resources Information Center

Davidhazy, Andrew

2009-01-01

The Imaging and Photographic Technology area, in which the author teaches, is an applications- and technology-oriented photography program designed to prepare students for work in technical, corporate, industrial, and scientific environments. One day, the author received an e-mail message from an editor who had found his Web site and thought he…

Environment Online: The Greening of Databases. Part 2. Scientific and Technical Databases.

ERIC Educational Resources Information Center

Alston, Patricia Gayle

1991-01-01

This second in a series of articles about online sources of environmental information describes scientific and technical databases that are useful for searching environmental data. Topics covered include chemicals and hazardous substances; agriculture; pesticides; water; forestry, oil, and energy resources; air; environmental and occupational…

[A case of the fatal injury by technical electricity from a mobile device (cell phone) connected to the circuit].

PubMed

Rudenko, I A; Kil'dyushov, E M; Koludarova, E M; Morozov, V Yu; Fetisov, V A

2015-01-01

The authors report a case of the fatal injury by technical electricity from a mobile device (cell phone) attached to the circuit in a moist environment as a result of the unsafe handling of the gadget (when taking the bath).

34 CFR 300.119 - Technical assistance and training activities.

Code of Federal Regulations, 2011 CFR

2011-07-01

... EDUCATION OF CHILDREN WITH DISABILITIES State Eligibility Least Restrictive Environment (lre) § 300.119... 34 Education 2 2011-07-01 2010-07-01 true Technical assistance and training activities. 300.119 Section 300.119 Education Regulations of the Offices of the Department of Education (Continued) OFFICE OF...

Succession Planning for Management Staff at a Canadian Post Secondary Technical Institute.

ERIC Educational Resources Information Center

da Costa, Jose; Cembrowski, Barbara

2001-01-01

Analyzed interviews to explore how nine administrators, at three different career stages, perceived career-development and succession planning at a Canadian postsecondary technical institute. Managers attribute career success to possession of varied personal attributes, diverse work experiences, serendipity, and a fulfilling work environment. Job…

Project DIVIDE Instrument Development. Technical Report # 0810

ERIC Educational Resources Information Center

Ketterlin-Geller, Leanne; Jung, Eunju; Geller, Josh; Yovanoff, Paul

2008-01-01

In this technical report, we describe the development of cognitive diagnostic test items that form the basis of the diagnostic system for Project DIVIDE (Dynamic Instruction Via Individually Designed Environments). The construct underlying the diagnostic test is division of fractions. We include a description of the process we used to identify the…

Technical Drafting and Mental Visualization in Interior Architecture Education

ERIC Educational Resources Information Center

Arslan, Ali Riza; Dazkir, Sibel Seda

2017-01-01

We explored how beginning-level interior architecture students develop skills to create mental visualizations of three-dimensional objects and environments, how they develop their technical drawing skills, and whether or not physical and computer generated models aid this design process. We used interviews and observations to collect data. The…

A Practical Approach to Early Technical Education

ERIC Educational Resources Information Center

Chijioke, M. O.

1973-01-01

A minimum of technological awareness is essential to Black Africa in its efforts to modernize itself. The young grow up deprived of an environment where they are made to feel at home with gadgets and machines. Elementary technical training and orderly exposure to mathematics are essential to child's education. (EB)

(Review Draft) Radiation Site Cleanup Regulations: Technical Support Document For The Development Of Radionuclide Cleanup Levels For Soil

EPA Pesticide Factsheets

This document describes parts of the technical analysis being undertaken in support of standards that ensure certain sites are cleaned up to a level that is protective of human health and the environment before they are released for public use.

NASA STI Program Coordinating Council Twelfth Meeting: Standards

NASA Technical Reports Server (NTRS)

1994-01-01

The theme of this NASA Scientific and Technical Information Program Coordinating Council Meeting was standards and their formation and application. Topics covered included scientific and technical information architecture, the Open Systems Interconnection Transmission Control Protocol/Internet Protocol, Machine-Readable Cataloging (MARC) open system environment procurement, and the Government Information Locator Service.

40 CFR 52.460 - Small business stationary source technical and environmental compliance assistance program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Small business stationary source... PLANS Delaware § 52.460 Small business stationary source technical and environmental compliance... Environmental Control submitted a plan for the establishment and implementation of a Small Business Stationary...

Encrustation of inarticulate brachiopods on scaphitid ammonites and inoceramid bivalves from the Upper Cretaceous U. S. Western Interior

NASA Astrophysics Data System (ADS)

Landman, Neil H.; Slattery, Joshua S.; Harries, Peter J.

2016-12-01

The inarticulate brachiopod Discinisca is a rare faunal element in the Upper Cretaceous of the U.S. Western Interior. We report two occurrences of encrustation of Discinisca on a scaphitid ammonite (scaphite) and several inoceramids from the lower Maastrichtian Baculites baculus/Endocostea typica Biozones of the Pierre Shale at two localities. Six specimens of Discinisca are present on a single specimen of Hoploscaphites crassus from east-central Montana. They occur along the furrow at the mature apertural margin. Because the brachiopods are restricted to the margin and do not occur on the rest of the shell, it is likely that they encrusted the ammonite during its lifetime. If so, this implies that the soft body of the scaphite did not cover the outside surface of the aperture, leaving this area vulnerable to epizoan attachment. A total of 13 specimens of Discinisca are also present on four specimens of Cataceramus? barabini from east-central Wyoming. The brachiopods occur in crevices on the outside of the shells and may have encrusted the inoceramids after their death as the shells began to break down and delaminate, resulting from the decomposition of the organic matrix holding them together. Based on the faunal assemblages at both localities, the presence of Discinisca may indicate environments with either low oxygen levels and/or few predators or competitors.

Species-specific differences in adaptive phenotypic plasticity in an ecologically relevant trophic trait: hypertrophic lips in Midas cichlid fishes.

PubMed

Machado-Schiaffino, Gonzalo; Henning, Frederico; Meyer, Axel

2014-07-01

The spectacular species richness of cichlids and their diversity in morphology, coloration, and behavior have made them an ideal model for the study of speciation and adaptive evolution. Hypertrophic lips evolved repeatedly and independently in African and Neotropical cichlid radiations. Cichlids with hypertrophic lips forage predominantly in rocky crevices and it has been hypothesized that mechanical stress caused by friction could result in larger lips through phenotypic plasticity. To test the influence of the environment on the size and development of lips, we conducted a series of breeding and feeding experiments on Midas cichlids. Full-sibs of Amphilophus labiatus (thick-lipped) and Amphilophus citrinellus (thin-lipped) each were split into a control group which was fed food from the water column and a treatment group whose food was fixed to substrates. We found strong evidence for phenotypic plasticity on lip area in the thick-lipped species, but not in the thin-lipped species. Intermediate phenotypic values were observed in hybrids from thick- and thin-lipped species reared under "control" conditions. Thus, both a genetic, but also a phenotypic plastic component is involved in the development of hypertrophic lips in Neotropical cichlids. Moreover, species-specific adaptive phenotypic plasticity was found, suggesting that plasticity is selected for in recent thick-lipped species. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Applied Space Systems Engineering. Chapter 17; Manage Technical Data

NASA Technical Reports Server (NTRS)

Kent, Peter

2008-01-01

Effective space systems engineering (SSE) is conducted in a fully electronic manner. Competitive hardware, software, and system designs are created in a totally digital environment that enables rapid product design and manufacturing cycles, as well as a multitude of techniques such as modeling, simulation, and lean manufacturing that significantly reduce the lifecycle cost of systems. Because the SSE lifecycle depends on the digital environment, managing the enormous volumes of technical data needed to describe, build, deploy, and operate systems is a critical factor in the success of a project. This chapter presents the key aspects of Technical Data Management (TDM) within the SSE process. It is written from the perspective of the System Engineer tasked with establishing the TDM process and infrastructure for a major project. Additional perspectives are reflected from the point of view of the engineers on the project who work within the digital engineering environment established by the TDM toolset and infrastructure, and from the point of view of the contactors who interface via the TDM infrastructure. Table 17.1 lists the TDM process as it relates to SSE.

Technical Tension Between Achieving Particulate and Molecular Organic Environmental Cleanliness: Data from Astromaterial Curation Laboratories

NASA Technical Reports Server (NTRS)

Allton, J. H.; Burkett, P. J.

2011-01-01

NASA Johnson Space Center operates clean curation facilities for Apollo lunar, Antarctic meteorite, stratospheric cosmic dust, Stardust comet and Genesis solar wind samples. Each of these collections is curated separately due unique requirements. The purpose of this abstract is to highlight the technical tensions between providing particulate cleanliness and molecular cleanliness, illustrated using data from curation laboratories. Strict control of three components are required for curating samples cleanly: a clean environment; clean containers and tools that touch samples; and use of non-shedding materials of cleanable chemistry and smooth surface finish. This abstract focuses on environmental cleanliness and the technical tension between achieving particulate and molecular cleanliness. An environment in which a sample is manipulated or stored can be a room, an enclosed glovebox (or robotic isolation chamber) or an individual sample container.

Deployment Area Selection and Land Withdrawal/Acquisition. M-X/MPS (M-X/Multiple Protective Shelter) Environmental Technical Report. Nye County, Nevada.

DTIC Science & Technology

1981-10-02

captures the environ- mental data and analysis in the document that was nearing com- pletion when the President decided to deploy the system in a...environmental technical " data from the Congress, federal agencies and the states involved, we have published limited copies of the document for their use...Land Withdrawal/Acquisition Environmental Impact Statement (FEIS) and its associated Environmental Technical Reports (ETRs). The data tables

Report: Results of Technical Network Vulnerability Assessment: EPA’s Radiation and Indoor Environments National Laboratory

EPA Pesticide Factsheets

Report #09-P-0053, December 9, 2008. Vulnerability testing of EPA’s Radiation and Indoor Environments National Laboratory (R&IEN) network identified Internet Protocol addresses with medium-risk vulnerabilities.

Certificate management entities for a connected vehicle environment : public workshop read-ahead document.

DOT National Transportation Integrated Search

2012-04-06

This document presents an overview of work conducted to date around development and analysis of organizational and operational models for certificate management in the connected vehicle environment. Functions, organizational models, technical backgro...

The University in the Networked Economy and Society: Challenges and Opportunities

ERIC Educational Resources Information Center

Benkler, Yochai

2008-01-01

The networked information economy and society present a new social, technical, and economic environment within which the university functions. To understand the new challenges and opportunities this environment presents, a usable characterization of the core new characteristics of both the environment and the university as a system and how those…

A Student Environment Model: A Measure of Institutional Effectiveness. AIR 1998 Annual Forum Paper.

ERIC Educational Resources Information Center

Morris-Baldwin, Darline

This study traces the development of a student environment model (SEM) at Texas State Technical College (Waco) that is used to assess students' perceptions of their college environment outside the formal classroom, provides baseline data for comparative analyses, establishes goals for student support services, measures program and process…

Using SOLO to Evaluate an Educational Virtual Environment in a Technology Education Setting

ERIC Educational Resources Information Center

Padiotis, Ioannis; Mikropoulos, Tassos A.

2010-01-01

The present research investigates the contribution of an interactive educational virtual environment on milk pasteurization to the learning outcomes of 40 students in a technical secondary school using SOLO taxonomy. After the interaction with the virtual environment the majority of the students moved to higher hierarchical levels of understanding…

Designing Environment for Teaching Internet of Things

ERIC Educational Resources Information Center

Simic, Konstantin; Vujin, Vladimir; Labus, Aleksandra; Stepanic, Ðorde; Stevanovic, Mladen

2014-01-01

One of the new topics taught at technical universities is Internet of Things. In this paper, a workshop for organizing a lab in academic environment for the subject Internet of Things is described. The architecture of the platform, scenario and a description of components used for creating the environment for learning Internet of things are also…

Hunting behavior of a marine mammal beneath the antarctic fast Ice

PubMed

Davis; Fuiman; Williams; Collier; Hagey; Kanatous; Kohin; Horning

1999-02-12

The hunting behavior of a marine mammal was studied beneath the Antarctic fast ice with an animal-borne video system and data recorder. Weddell seals stalked large Antarctic cod and the smaller subice fish Pagothenia borchgrevinki, often with the under-ice surface for backlighting, which implies that vision is important for hunting. They approached to within centimeters of cod without startling the fish. Seals flushed P. borchgrevinki by blowing air into subice crevices or pursued them into the platelet ice. These observations highlight the broad range of insights that are possible with simultaneous recordings of video, audio, three-dimensional dive paths, and locomotor effort.

Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

DOEpatents

Kikta, Thomas J.; Mitchell, Ronald D.

1992-01-01

A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet.

Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

DOEpatents

Kikta, T.J.; Mitchell, R.D.

1992-11-24

A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet. 4 figs.

The design of superhydrophobic stainless steel surfaces by controlling nanostructures: A key parameter to reduce the implantation of pathogenic bacteria.

PubMed

Bruzaud, Jérôme; Tarrade, Jeanne; Celia, Elena; Darmanin, Thierry; Taffin de Givenchy, Elisabeth; Guittard, Frédéric; Herry, Jean-Marie; Guilbaud, Morgan; Bellon-Fontaine, Marie-Noëlle

2017-04-01

Reducing bacterial adhesion on substrates is fundamental for various industries. In this work, new superhydrophobic surfaces are created by electrodeposition of hydrophobic polymers (PEDOT-F 4 or PEDOT-H 8 ) on stainless steel with controlled topographical features, especially at a nano-scale. Results show that anti-bioadhesive and anti-biofilm properties require the control of the surface topographical features, and should be associated with a low adhesion of water onto the surface (Cassie-Baxter state) with limited crevice features at the scale of bacterial cells (nano-scale structures). Copyright © 2016. Published by Elsevier B.V.

ECLSS Sustaining Metal Materials Compatibility Final Report, Electrochemical and Crevice Corrosion Test Results

NASA Technical Reports Server (NTRS)

Lee, R. E.

2015-01-01

Electrochemical test results are presented for six noble metals evaluated in two acidic test solutions which are representative of waste liquids processed in the Environmental Control and Life Support System (ECLSS) aboard the International Space Station (ISS). The two test solutions consisted of fresh waste liquid which had been modified with a proposed or alternate pretreatment formulation and its associated brine concentrate. The six test metals included three titanium grades, (Commercially Pure, 6Al-4V alloy and 6Al-4V Low Interstitial alloy), two nickel-chromium alloys (Inconel® 625 and Hastelloy® C276), and one high tier stainless steel (Cronidur® 30).

The Use of Virtual Reality Simulation to Improve Technical Skill in the Undergraduate Medical Imaging Student

ERIC Educational Resources Information Center

Gunn, Therese; Jones, Lee; Bridge, Pete; Rowntree, Pam; Nissen, Lisa

2018-01-01

In recent years, simulation has increasingly underpinned the acquisition of pre-clinical skills by undergraduate medical imaging (diagnostic radiography) students. This project aimed to evaluate the impact of an innovative virtual reality (VR) learning environment on the development of technical proficiency by students. The study assessed the…

An Exploration of Desktop Virtual Reality and Visual Processing Skills in a Technical Training Environment

ERIC Educational Resources Information Center

Ausburn, Lynna J.; Ausburn, Floyd B.; Kroutter, Paul

2010-01-01

Virtual reality (VR) technology has demonstrated effectiveness in a variety of technical learning situations, yet little is known about its differential effects on learners with different levels of visual processing skill. This small-scale exploratory study tested VR through quasi-experimental methodology and a theoretical/conceptual framework…

Task-Based EFL Language Teaching with Procedural Information Design in a Technical Writing Context

ERIC Educational Resources Information Center

Roy, Debopriyo

2017-01-01

Task-based language learning (TBLL) has heavily influenced syllabus design, classroom teaching, and learner assessment in a foreign or second language teaching context. In this English as foreign language (EFL) learning environment, the paper discussed an innovative language learning pedagogy based on design education and technical writing. In…

Space transfer concepts and analyses for exploration missions

NASA Technical Reports Server (NTRS)

Woodcock, Gordon R.

1992-01-01

The current technical effort is part of the third phase of a broad-scoped and systematic study of space transfer concepts for human lunar and Mars missions. The study addressed the technical issues relating to the First Lunar Outpost (FLO) habitation vehicle with emphasis in the structure, power, life support system, and radiation environment.

Adults with Cognitive Disabilities in the Technical Sector

ERIC Educational Resources Information Center

Gronsky, Stacy A.

2015-01-01

Given the number of jobs created in the technical sector (Casserly, 2012), it is essential to identify how adults with cognitive disabilities can be best supported in professional environments and evolving sectors. Some career paths and jobs can be more understanding of learning disabilities than others (Nicholas, 2011). This is dependent not only…

Education Student Perceptions of Virtual Reality as a Learning Tool

ERIC Educational Resources Information Center

Domingo, Jelia R.; Bradley, Elizabeth Gates

2018-01-01

The purpose of this study was to ascertain student perceptions of the use and value of three-dimensional virtual environments. A grounded theory approach was used to gather and examine data. Just over half of student participants reported positive experiences. However, most experienced technical difficulties. Despite the technical challenges of…

A Study of College Professors' Perceptions of International Students in STEM Classrooms at a Technical University

ERIC Educational Resources Information Center

Abendschein, Barbara Feeney

2017-01-01

This study investigated the perceptions of STEM professors at a Southeastern technical college about the international students in their undergraduate classrooms, including impact on the learning environment, academic abilities and proficiency in meeting course goals, contribution to class activities and recommendations for improved preparation.…

Influence of End Customer Exposure on Product Design within an Epistemic Game Environment

ERIC Educational Resources Information Center

Markovetz, Matthew R.; Clark, Renee M.; Swiecki, Zachari; Irgens, Golnaz Arastoopour; Chesler, Naomi C.; Shaffer, David W.; Bodnar, Cheryl A.

2017-01-01

Engineering product design requires both technical aptitude and an understanding of the nontechnical requirements in the marketplace, economic or otherwise. Engineering education has long focused on the technical side of product design, but there is increasing demand for market-aware engineers in industry. Market-awareness and customer-focus are…

Accessing technical data bases using STDS: A collection of scenarios

NASA Technical Reports Server (NTRS)

Hardgrave, W. T.

1975-01-01

A line by line description is given of sessions using the set-theoretic data system (STDS) to interact with technical data bases. The data bases contain data from actual applications at NASA Langley Research Center. The report is meant to be a tutorial document that accompanies set processing in a network environment.

Application of Semantic Approaches and Interactive Virtual Technology to Improve Teaching Effectiveness

ERIC Educational Resources Information Center

Jou, Min; Liu, Chi-Chia

2012-01-01

This article describes an implementation of interactive virtual environments that have been designed for supporting the education of technical skills in material processing technology. The developed web-based systems provide the capability to train students in the technical skills of material processing technology without the need to work on…

Teaching Technology with Technology. An Off-the-Shelf Robotics Course Builds Technical Center Enrollment.

ERIC Educational Resources Information Center

Hannemann, Jim; Rice, Thomas R.

1991-01-01

At the Oakland Technical Center, which provides vocational programs for nine Michigan high schools, a one-semester course in Foundations of Technology Systems uses a computer-simulated manufacturing environment to teach applied math, science, language arts, communication skills, problem solving, and teamwork in the context of technology education.…

Helping Doctoral Students Establish Long-Term Identities as Technical Communication Scholars

ERIC Educational Resources Information Center

Grant-Davie, Keith; Matheson, Breeanne; Stephens, Eric James

2017-01-01

This article aims to help doctoral students in technical communication prepare themselves for the academic job market and for the subsequent process of earning tenure and promotion in increasingly demanding environments. The authors propose that students do four things: (a) learn to spot and articulate research problems; (b) find their…

Deployment Area Selection and Land Withdrawal/Acquisition. M-X/MPS (M-X/Multiple Protective Shelter) Environmental Technical Report. Washington County, Utah.

DTIC Science & Technology

1981-10-02

file a FEIS for the MPS system. However, the attached preliminary FEIS captures the environ- mental data and analysis in the document that was nearing...efforts in the study area. There- fore, in response to requests for environmental technical data from the Congress, federal agencies and the states involved...associated Environmental Technical Reports (ETRs). The data tables presented here provide projections of the key socioeconomic impacts of M-X deployment for

Guiding bioprocess design by microbial ecology.

PubMed

Volmer, Jan; Schmid, Andreas; Bühler, Bruno

2015-06-01

Industrial bioprocess development is driven by profitability and eco-efficiency. It profits from an early stage definition of process and biocatalyst design objectives. Microbial bioprocess environments can be considered as synthetic technical microbial ecosystems. Natural systems follow Darwinian evolution principles aiming at survival and reproduction. Technical systems objectives are eco-efficiency, productivity, and profitable production. Deciphering technical microbial ecology reveals differences and similarities of natural and technical systems objectives, which are discussed in this review in view of biocatalyst and process design and engineering strategies. Strategies for handling opposing objectives of natural and technical systems and for exploiting and engineering natural properties of microorganisms for technical systems are reviewed based on examples. This illustrates the relevance of considering microbial ecology for bioprocess design and the potential for exploitation by synthetic biology strategies. Copyright © 2015 Elsevier Ltd. All rights reserved.

Technology and Policy: Looking to the Future

NASA Astrophysics Data System (ADS)

Sylvester, Kory

2009-05-01

As the proper scope and nature of arms control continues to be debated, it is certain that technical capabilities and advice will play a significant role. While national priorities and strategic objectives and broader perspectives of international security and foreign policy will ultimately dictate, technical expertise and assessment is critical to the identification, development and evaluation of alternatives. Strategic linkages between arms control, nonproliferation, and homeland security have perhaps never been so intertwined. Incomplete information and strongly held but disparate views about the potential of science and technology to amplify threats as readily as they mitigate them creates a highly dynamic environment for policymakers. To contribute meaningfully scientists and engineers will have to remain engaged with national security debates and think about the strategic and policy environment in which technical questions are posed to them, and how to identify and frame the important questions that aren't.

Assessing team performance in the operating room: development and use of a "black-box" recorder and other tools for the intraoperative environment.

PubMed

Guerlain, Stephanie; Adams, Reid B; Turrentine, F Beth; Shin, Thomas; Guo, Hui; Collins, Stephen R; Calland, J Forrest

2005-01-01

The objective of this research was to develop a digital system to archive the complete operative environment along with the assessment tools for analysis of this data, allowing prospective studies of operative performance, intraoperative errors, team performance, and communication. Ability to study this environment will yield new insights, allowing design of systems to avoid preventable errors that contribute to perioperative complications. A multitrack, synchronized, digital audio-visual recording system (RATE tool) was developed to monitor intraoperative performance, including software to synchronize data and allow assignment of independent observational scores. Cases were scored for technical performance, participants' situational awareness (knowledge of critical information), and their comfort and satisfaction with the conduct of the procedure. Laparoscopic cholecystectomy (n = 10) was studied. Technical performance of the RATE tool was excellent. The RATE tool allowed real time, multitrack data collection of all aspects of the operative environment, while permitting digital recording of the objective assessment data in a time synchronized and annotated fashion during the procedure. The mean technical performance score was 73% +/- 28% of maximum (perfect) performance. Situational awareness varied widely among team members, with the attending surgeon typically the only team member having comprehensive knowledge of critical case information. The RATE tool allows prospective analysis of performance measures such as technical judgments, team performance, and communication patterns, offers the opportunity to conduct prospective intraoperative studies of human performance, and allows for postoperative discussion, review, and teaching. This study also suggests that gaps in situational awareness might be an underappreciated source of operative adverse events. Future uses of this system will aid teaching, failure or adverse event analysis, and intervention research.

The Telecommunications Environment and Its Implications for System Design.

ERIC Educational Resources Information Center

Learn, Larry L.; McGill, Michael J.

1984-01-01

Discusses changing telecommunications environment and effect these changes might have on information systems design. Major telecommunications factors and trends reviewed are classified as technical (application of computer technologies to classical telecommunications problems), economic, and regulatory policy related (divestiture of American…

"Everyman" and his Environment.

ERIC Educational Resources Information Center

Kinney, John E.

Although we have accumulated much factual data on environmental conditions, interrelationships, and consequences of actions, our decisions are based on political expediency, pressure, mob action, and emotion. Believing that decisions regarding the environment and pollution control are not technical but socioeconomic, crusaders have refused…

Performance of high performance concrete (HPC) in low pH and sulfate environment : [technical summary].

DOT National Transportation Integrated Search

2013-01-01

High-performance concrete (HPC) refers to any concrete formulation with enhanced characteristics, compared to normal concrete. One might think this refers to strength, but in Florida, the HPC standard emphasizes withstanding aggressive environments, ...

Perturbed Communication in a Virtual Environment to Train Medical Team Leaders.

PubMed

Huguet, Lauriane; Lourdeaux, Domitile; Sabouret, Nicolas; Ferrer, Marie-Hélène

2016-01-01

The VICTEAMS project aims at designing a virtual environment for training medical team leaders to non-technical skills. The virtual environment is populated with autonomous virtual agents who are able to make mistakes (in action or communication) in order to train rescue team leaders and to make them adaptive with all kinds of situations or teams.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Technical Reports Server (NTRS)

Monell, Donald W.; Piland, William M.

1999-01-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g. manufacturing and systems operations). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often lead to the inability of assessing critical programmatic and technical issues (e.g., cost risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographically distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across the Agency.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Technical Reports Server (NTRS)

Monell, Donald W.; Piland, William M.

2000-01-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g., manufacturing and systems operation). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often lead to the inability of assessing critical programmatic and technical issues (e.g., cost, risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographical distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across Agency.

Aerospace Systems Design in NASA's Collaborative Engineering Environment

NASA Astrophysics Data System (ADS)

Monell, Donald W.; Piland, William M.

2000-07-01

Past designs of complex aerospace systems involved an environment consisting of collocated design teams with project managers, technical discipline experts, and other experts (e.g., manufacturing and systems operations). These experts were generally qualified only on the basis of past design experience and typically had access to a limited set of integrated analysis tools. These environments provided less than desirable design fidelity, often led to the inability of assessing critical programmatic and technical issues (e.g., cost, risk, technical impacts), and generally derived a design that was not necessarily optimized across the entire system. The continually changing, modern aerospace industry demands systems design processes that involve the best talent available (no matter where it resides) and access to the best design and analysis tools. A solution to these demands involves a design environment referred to as collaborative engineering. The collaborative engineering environment evolving within the National Aeronautics and Space Administration (NASA) is a capability that enables the Agency's engineering infrastructure to interact and use the best state-of-the-art tools and data across organizational boundaries. Using collaborative engineering, the collocated team is replaced with an interactive team structure where the team members are geographically distributed and the best engineering talent can be applied to the design effort regardless of physical location. In addition, a more efficient, higher quality design product is delivered by bringing together the best engineering talent with more up-to-date design and analysis tools. These tools are focused on interactive, multidisciplinary design and analysis with emphasis on the complete life cycle of the system, and they include nontraditional, integrated tools for life cycle cost estimation and risk assessment. NASA has made substantial progress during the last two years in developing a collaborative engineering environment. NASA is planning to use this collaborative engineering infrastructure to provide better aerospace systems life cycle design and analysis, which includes analytical assessment of the technical and programmatic aspects of a system from "cradle to grave." This paper describes the recent NASA developments in the area of collaborative engineering, the benefits (realized and anticipated) of using the developed capability, and the long-term plans for implementing this capability across the Agency.

Biointerfaces for Two-way Communication to Assess Hazards in the Aquatic Environment.

DTIC Science & Technology

1999-11-01

to provide timely information on contaminants in freshwater and marine environments. 14. SUBJECT TERMS 15. NUMBER OF PAGES Sentinel species, aquatic ...for using aquatic organisms to provide timely information on contaminants in freshwater and marine environments. Some of the research challenges that...Technical Report 0001 Biointerfaces for Two-way Communication to Assess Hazards in the Aquatic Environment U.S. Army Center for Environmental Health

Development of Graduates' Attributes in Chemistry within an Open Distance Learning (ODL) Environment: UNISA's Experience

ERIC Educational Resources Information Center

Tafesse, Fikru; Mphahlele, Malose J.

2018-01-01

Discipline-specific knowledge and associated technical skills as well as generic skills have represented distinct and separate aspects of chemical sciences in university studies (linear training). In addition to technical skills gained through laboratory training, employers now require a soft skill set such as strengths in analytical thinking,…

Managing Technical and Cost Uncertainties During Product Development in a Simulation-Based Design Environment

NASA Technical Reports Server (NTRS)

Karandikar, Harsh M.

1997-01-01

An approach for objective and quantitative technical and cost risk analysis during product development, which is applicable from the earliest stages, is discussed. The approach is supported by a software tool called the Analytical System for Uncertainty and Risk Estimation (ASURE). Details of ASURE, the underlying concepts and its application history, are provided.

Credit with Education and Title II Programs. Technical Note. Food and Nutrition Technical Assistance.

ERIC Educational Resources Information Center

Reid, Helen

"Credit with Education" is a way to provide self-financing microfinance (or small-scale banking) to women, primarily in very poor rural areas, while at the same time providing education for business and family survival. Within the village banking environment, attempts to integrate education with village bank meetings have fallen into two…

Increasing Student Interaction in Technical Writing Courses in Online Environments

ERIC Educational Resources Information Center

Virtue, Drew

2017-01-01

This article examines how the levels of student interaction change through the use of small groups and moderators in online writing courses. The study examines three technical and professional online writing courses: one course that employs small groups and group moderators and two courses that have no small groups or moderators. The results of…

(White House Conference on Aging, 1981. Health Maintenance and Health Promotion. Report and Executive Summary of the Technical Committee.)

ERIC Educational Resources Information Center

Farber, Seymour M.; And Others

The introduction to this Technical Committee Report reviews the health status of the older population and examines major disease entities where health maintenance and promotion can play a role. Part One, "Health Maintenance and Health Promotion Services," discusses the physical and social environments, indicators of change in physical…

Experience of Technical Disciplines Remote Training at the St. Petersburg State University of Architecture and Civil Engineering

ERIC Educational Resources Information Center

Glukhikh, Vladimir Nikolaevich; Norina, Natalia Vladimirovna

2016-01-01

This paper reveals the main trends and characteristics of the use of multimedia means in distance learning of technical subjects at graduate schools; analyses the peculiarities of presentation and perception of information in multimedia environment; and studies genre and topic structure of multimedia means used for distance learning. The author…

Annual Technical Progress Report for Emergency School Assistance Program, Title 45, 1970-71.

ERIC Educational Resources Information Center

Lindsey, Randall B.

This paper presents a technical progress report of two programs conducted with funds provided under the Emergency School Assistance Program. One, the Mobile Learning Unit, said to have been designed to measure changes in fourth and fifth grade students' self-concept in a reorganized desegregated school environment, focuses on whether a positive…

Integration of gas chromatographs into the Federal Highway Administration/Environmental Protection Agency near road MSAT study in Las Vegas, NV

EPA Science Inventory

This paper documents the technical evaluation of a semi-continuous gas chromatograph (GC) for the measurement of benzene and 1,33butadiene in the near road environment. This paper will also consider the some of the non-technical implications associated with the operation of a GC ...

Identifying Students' Difficulties When Learning Technical Skills via a Wireless Sensor Network

ERIC Educational Resources Information Center

Wang, Jingying; Wen, Ming-Lee; Jou, Min

2016-01-01

Practical training and actual application of acquired knowledge and techniques are crucial for the learning of technical skills. We established a wireless sensor network system (WSNS) based on the 5E learning cycle in a practical learning environment to improve students' reflective abilities and to reduce difficulties for the learning of technical…

40 CFR 52.2633 - Stack height regulations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Stack height regulations. 52.2633 Section 52.2633 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... with the “Guideline for Determination of Good Engineering Practice Stack Height (Technical Support...

Implementing DSpace at NASA Langley Research Center

NASA Technical Reports Server (NTRS)

Lowe, Greta

2007-01-01

This presentation looks at the implementation of the DSpace institutional repository system at the NASA Langley Technical Library. NASA Langley Technical Library implemented DSpace software as a replacement for the Langley Technical Report Server (LTRS). DSpace was also used to develop the Langley Technical Library Digital Repository (LTLDR). LTLDR contains archival copies of core technical reports in the aeronautics area dating back to the NACA era and other specialized collections relevant to the NASA Langley community. Extensive metadata crosswalks were created to facilitate moving data from various systems and formats to DSpace. The Dublin Core metadata screens were also customized. The OpenURL standard and Ex Libris Metalib are being used in this environment to assist our customers with either discovering full-text content or with initiating a request for the item.

[Forensic-medical diagnostics of an electrical mark resulting from the injury inflicted by technical electricity in the aqueous environment].

PubMed

Pigolkin, Iu I; Skovorodnikov, S V; Dubrovin, I A

2014-01-01

The objective of the present study was to develop the criteria for forensic-medical diagnostics of an electrical injury inflicted in the aqueous environment based on the characteristics of the electrical mark. The specific morphological features of the electrical injuries inflicted in the aqueous environment that were discovered in the materials available for the forensic medical expertise were analysed taking into consideration the results of the relevant research reported in the forensic medical literature. It was shown that an electrical injury inflicted in the aqueous environment results in the formation of an unusual mark in the form of blisters containing no watery liquid associated with electrogenic oedema in the surrounding tissues. Macroscopic and microscopic studies of the electrical mark failed to reveal the signs of grade III and IV grade thermal burning or thermally affected hair. It is concluded that the consistent characteristics of the electrical mark resulting from the injury inflicted by technical electricity in the aqueous environment include cell lengthening, blister formation inside the corneal layer, and the separation of epidermis from the skin proper.

Technical experiences of implementing a wireless tracking and facial biometric verification system for a clinical environment

NASA Astrophysics Data System (ADS)

Liu, Brent; Lee, Jasper; Documet, Jorge; Guo, Bing; King, Nelson; Huang, H. K.

2006-03-01

By implementing a tracking and verification system, clinical facilities can effectively monitor workflow and heighten information security in today's growing demand towards digital imaging informatics. This paper presents the technical design and implementation experiences encountered during the development of a Location Tracking and Verification System (LTVS) for a clinical environment. LTVS integrates facial biometrics with wireless tracking so that administrators can manage and monitor patient and staff through a web-based application. Implementation challenges fall into three main areas: 1) Development and Integration, 2) Calibration and Optimization of Wi-Fi Tracking System, and 3) Clinical Implementation. An initial prototype LTVS has been implemented within USC's Healthcare Consultation Center II Outpatient Facility, which currently has a fully digital imaging department environment with integrated HIS/RIS/PACS/VR (Voice Recognition).

Aging Well and the Environment: Toward an Integrative Model and Research Agenda for the Future

ERIC Educational Resources Information Center

Wahl, Hans-Werner; Iwarsson, Susanne; Oswald, Frank

2012-01-01

Purpose of the Study: The effects of the physical-spatial-technical environment on aging well have been overlooked both conceptually and empirically. In the spirit of M. Powell Lawton's seminal work on aging and environment, this article attempts to rectify this situation by suggesting a new model of how older people interact with their…

Instructional Features for Training in Virtual Environments

DTIC Science & Technology

2006-07-01

Technical Report 1184 Instructional Features for Training in Virtual Environments Michael J. Singer U. S. Army Research Institute Jason P. Kring...Report 1184 Instructional Features for Training in Virtual Environments Michael J. Singer U. S. Army Research Institute Jason P. Kring University of...provides in comparison to traditional, real world experience training programs (Hays & Singer , 1989; Swezey & Andrews, 2001). First, as with the

Reaching African-American Youth Who Live in High-Risk Environments. Technical Assistance Bulletin.

ERIC Educational Resources Information Center

Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Center for Substance Abuse Prevention.

To support community efforts to reach out to African American youth confronted with high-risk environments in the cities, the Center for Substance Abuse Prevention has launched the Urban Youth Public Education Campaign. This campaign targets 9- to 13-year-old African American youth in high-risk inner-city environments. The campaign is designed to…

Defining and Building an Enriched Learning and Information Environment.

ERIC Educational Resources Information Center

Goodrum, David A.; And Others

1993-01-01

Discusses the development of an Enriched Learning and Information Environment (ELIE). Highlights include technology-based and theory-based frameworks for defining ELIEs; a socio-technical definition; a conceptual prototype; a participatory design process, including iterative design through rapid prototyping; and design issues for technology…

[The Engineering and Technical Services Directorate at the Glenn Research Center

NASA Technical Reports Server (NTRS)

Moon, James

2004-01-01

My name is James Moon and I am a senior at Tennessee State University where my major is Aeronautical and Industrial Technology with a concentration in industrial electronics. I am currently serving my internship in the Engineering and Technical Services Directorate at the Glenn Research Center (GRC). The Engineering and Technical Service Directorate provides the services and infrastructure for the Glenn Research Center to take research concepts to reality. They provide a full range of integrated services including engineering, advanced prototyping and testing, facility management, and information technology for NASA, industry, and academia. Engineering and Technical Services contains the core knowledge in Information Technology (IT). This includes data systems and analysis, inter and intranet based systems design and data security. Including the design and development of embedded real-time s o h a r e applications for flight and supporting ground systems, Engineering and Technical Services provide a wide range of IT services and products specific to the Glenn Research Center research and engineering community. In the 7000 Directorate I work directly in the 7611 organization. This organization is known as the Aviation Environments Technical Branch. My mentor is Vincent Satterwhite who is also the Branch Chief of the Aviation Environments Technical Branch. In this branch, I serve as the Assistant program manager of the Engineering Technology Program. The Engineering Technology Program (ETP) is one of three components of the High School L.E.R.C.I.P. This is an Agency-sponsored, eight-week research-based apprenticeship program designed to attract traditionally underrepresented high school students that demonstrate an aptitude for and interest in mathematics, science, engineering, and technology.

Feasibility study for the Swaziland/Mozambique interconnector. EPC specifications. Export trade information

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

NONE

1997-11-01

This study, conducted by Black & Veatch, was funded by the U.S. Trade and Development Agency. The report, produced for the Ministry of National Resources, Energy and Environment (MNRE) of Swaziland, determines the least cost capacity expansion option to meet the future power demand and system reliability criteria of Swaziland, with particular emphasis on the proposed Interconnector between Swaziland and Mozambique. Volume 3 contains EPC Specifications and is divided into the following divisions: (1) Commercial; (2) General Technical Requirements; (3) Transmission Line Technical Requirements; (4) Substation Technical Requirements; (5) Specifications.

Magnetic Earth Ionosphere Resonant Frequencies

NASA Technical Reports Server (NTRS)

Spaniol, Craig

1994-01-01

The Community College Division is pleased to report progress of NASA funded research at West Virginia State College. During this reporting period, the project research group has continued with activities to develop instrumentation capability designed to monitor resonant cavity frequencies in the atmospheric region between the Earth's surface and the ionosphere. In addition, the project's principal investigator, Dr. Craig Spaniol, and NASA technical officer, Dr. John Sutton, have written and published technical papers intended to expand the scientific and technical framework needed for project research. This research continues to provide an excellent example of government and education working together to provide significant research in the college environment. This cooperative effort has provided many students with technical project work which compliments their education.

Robotic Arm-Assisted Sonography: Review of Technical Developments and Potential Clinical Applications.

PubMed

Swerdlow, Daniel R; Cleary, Kevin; Wilson, Emmanuel; Azizi-Koutenaei, Bamshad; Monfaredi, Reza

2017-04-01

Ultrasound imaging requires trained personnel. Advances in robotics and data transmission create the possibility of telesonography. This review introduces clinicians to current technical work in and potential applications of this developing capability. Telesonography offers advantages in hazardous or remote environments. Robotically assisted ultrasound can reduce stress injuries in sonographers and has potential utility during robotic surgery and interventional procedures.

Partners in Community Service: Making a Community Connection Is Part of "The Stafford Way" at Vermont's Stafford Technical Center

ERIC Educational Resources Information Center

Lucci, William, Jr.

2005-01-01

The Stafford Technical Center (STC) in Rutland, Vermont, operates with a mission statement that proudly touts its desire to "create a learning environment that promotes pride in work, a sense of self-worth and the ability to respect others by developing effective communication and life skills." Stafford acknowledges that these learning…

Distance Education Programs in Texas Community & Technical Colleges: Assessing Student Support Services in a Virtual Environment.

ERIC Educational Resources Information Center

Luedtke, Cherry Beth

This project evaluates the status of distance learning at 54 public, two-year community, and technical colleges in Texas. Data was collected from the Web sites of each of the institutions. The Web site data indicted that 44 of the colleges refer specifically to distance education courses offered. To assess what student support services are…

Norm-Aware Socio-Technical Systems

NASA Astrophysics Data System (ADS)

Savarimuthu, Bastin Tony Roy; Ghose, Aditya

The following sections are included: * Introduction * The Need for Norm-Aware Systems * Norms in human societies * Why should software systems be norm-aware? * Case Studies of Norm-Aware Socio-Technical Systems * Human-computer interactions * Virtual environments and multi-player online games * Extracting norms from big data and software repositories * Norms and Sustainability * Sustainability and green ICT * Norm awareness through software systems * Where To, From Here? * Conclusions

Not just trust: factors influencing learners' attempts to perform technical skills on real patients.

PubMed

Bannister, Susan L; Dolson, Mark S; Lingard, Lorelei; Keegan, David A

2018-06-01

As part of their training, physicians are required to learn how to perform technical skills on patients. The previous literature reveals that this learning is complex and that many opportunities to perform these skills are not converted into attempts to do so by learners. This study sought to explore and understand this phenomenon better. A multi-phased qualitative study including ethnographic observations, interviews and focus groups was conducted to explore the factors that influence technical skill learning. In a tertiary paediatric emergency department, staff physician preceptors, residents, nurses and respiratory therapists were observed in the delivery and teaching of technical skills over a 3-month period. A constant comparison methodology was used to analyse the data and to develop a constructivist grounded theory. We conducted 419 hours of observation, 18 interviews and four focus groups. We observed 287 instances of technical skills, of which 27.5% were attempted by residents. Thematic analysis identified 14 factors, grouped into three categories, which influenced whether residents attempted technical skills on real patients. Learner factors included resident initiative, perceived need for skill acquisition and competing priorities. Teacher factors consisted of competing priorities, interest in teaching, perceived need for residents to acquire skills, attributions about learners, assessments of competency, and trust. Environmental factors were competition from other learners, judgement that the patient was appropriate, buy-in from team members, consent from patient or caregivers, and physical environment constraints. Our findings suggest that neither the presence of a learner in a clinical environment nor the trust of the supervisor is sufficient to ensure the learner will attempt a technical skill. We characterise this phenomenon as representing a pool of opportunities to conduct technical skills on live patients that shrinks to a much smaller pool of technical skill attempts. Learners, teachers and educators can use this knowledge to maximise the number of attempts learners make to perform technical skills on real patients. © 2018 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

Designing Distributed Learning Environments with Intelligent Software Agents

ERIC Educational Resources Information Center

Lin, Fuhua, Ed.

2005-01-01

"Designing Distributed Learning Environments with Intelligent Software Agents" reports on the most recent advances in agent technologies for distributed learning. Chapters are devoted to the various aspects of intelligent software agents in distributed learning, including the methodological and technical issues on where and how intelligent agents…

The Learning Environment.

ERIC Educational Resources Information Center

American Electric Power System, New York, NY.

The basic factors in personal comfort, the nature of the processes of teaching and learning, and the effects of environment on these functions are discussed. The role of climate conditioning and space conditioning as interpreted by sensory factors during the learning process gives guidelines for design solutions. Technical supplements on climate…

Coping with Uncertainty in an Agile Systems Development Course

ERIC Educational Resources Information Center

Taipalus, Toni; Seppänen, Ville; Pirhonen, Maritta

2018-01-01

Uncertain and ambiguous environments are commonplace in information systems development (ISD) projects, and while different Agile frameworks welcome changes in organizational, technical, and business environments, the incurred uncertainty is known to negatively affect the development process and the quality of the final product. The effects of…

Life expectancy of modular Ti6Al4V hip implants: influence of stress and environment.

PubMed

Chandra, A; Ryu, J J; Karra, P; Shrotriya, P; Tvergaard, V; Gaisser, M; Weik, T

2011-11-01

Stress dependent electrochemical dissolution is identified as one of the key mechanisms governing surface degradation in fretting and crevice corrosion of biomedical implants. The present study focuses on delineating the roles of mechanical stress and chemical conditions on the life expectancy of modular hip implants. First, material removal on a stressed surface of Ti6Al4V subjected to single asperity contact is investigated experimentally to identify the influence of contact load, in-plane stress and chemical environment on mean wear rates. A range of known stress levels are applied to the specimen while its surface is mechanically stimulated in different non-reactive to oxidizing aqueous environments. Evolution of surface degradation is monitored, and its mechanism is elucidated. This phase allows estimation of Preston Constant which is later used in the analysis. Second phase of the work is semi-analytical and computational, where, based on the estimated Preston constant and other material and process parameters, the scratch propensity (consisting of magnitude of scratch depth and their frequency per unit area) due to micro-motion in modular hip implants is estimated. The third phase views these scratches as initial notches and utilizes a mixed-mode fatigue crack propagation model to estimate the critical crack length for onset of instability. The number of loading cycles needed to reach this critical crack length is then labeled as the expected life of the implant under given mechanical and chemical conditions. Implications of different material and process conditions to life expectancy of orthopedic implants are discussed. It is observed that transverse micro-motion, compared to longitudinal micro-motion, plays a far more critical role in determining the implant life. Patient body weight, as well as proximity of the joint fluid to its iso-electric point play key roles in determining wear rates and associated life expectancies of modular hip implants. Sustained aeration of joint fluid, as well as proper tolerancing of mating surfaces, along with a proper choice of material microstructure may be utilized to extend implant life. Copyright © 2011 Elsevier Ltd. All rights reserved.

Performance and efficiency evaluation and heat release study of a direct-injection stratified-charge rotary engine

NASA Technical Reports Server (NTRS)

Nguyen, H. L.; Addy, H. E.; Bond, T. H.; Lee, C. M.; Chun, K. S.

1987-01-01

A computer simulation which models engine performance of the Direct Injection Stratified Charge (DISC) rotary engines was used to study the effect of variations in engine design and operating parameters on engine performance and efficiency of an Outboard Marine Corporation (OMC) experimental rotary combustion engine. Engine pressure data were used in a heat release analysis to study the effects of heat transfer, leakage, and crevice flows. Predicted engine data were compared with experimental test data over a range of engine speeds and loads. An examination of methods to improve the performance of the rotary engine using advanced heat engine concepts such as faster combustion, reduced leakage, and turbocharging is also presented.

Cracks and crevices: globalization discourse and medical education.

PubMed

Hodges, Brian David; Maniate, Jerry M; Martimianakis, Maria Athina Tina; Alsuwaidan, Mohammad; Segouin, Christophe

2009-10-01

Globalization discourse, and its promises of a 'flat world', 'borderless economy' and 'mobility of ideas and people', has become very widespread in all fields. In medical education this discourse is underpinned by assumptions that medical competence has universal elements and that medical education can therefore develop 'global standards' for accreditation, curricula and examinations. Yet writers in the field other than medicine have raised a number of concerns about an overemphasis on the economic aspects of globalization. This article explores the notion that it is time to study and embrace differences and discontinuities in goals, practices and values that underpin medical competence in different countries and to critically examine the promises-realized or broken-of globalization discourse in medical education.

Recognition and inference of crevice processing on digitized paintings

NASA Astrophysics Data System (ADS)

Karuppiah, S. P.; Srivatsa, S. K.

2013-03-01

This paper is designed to detect and removal of cracks on digitized paintings. The cracks are detected by threshold. Afterwards, the thin dark brush strokes which have been misidentified as cracks are removed using Median radial basis function neural network on hue and saturation data, Semi-automatic procedure based on region growing. Finally, crack is filled using wiener filter. The paper is well designed in such a way that most of the cracks on digitized paintings have identified and removed. The paper % of betterment is 90%. This paper helps us to perform not only on digitized paintings but also the medical images and bmp images. This paper is implemented by Mat Lab.

Are Cloud Environments Ready for Scientific Applications?

NASA Astrophysics Data System (ADS)

Mehrotra, P.; Shackleford, K.

2011-12-01

Cloud computing environments are becoming widely available both in the commercial and government sectors. They provide flexibility to rapidly provision resources in order to meet dynamic and changing computational needs without the customers incurring capital expenses and/or requiring technical expertise. Clouds also provide reliable access to resources even though the end-user may not have in-house expertise for acquiring or operating such resources. Consolidation and pooling in a cloud environment allow organizations to achieve economies of scale in provisioning or procuring computing resources and services. Because of these and other benefits, many businesses and organizations are migrating their business applications (e.g., websites, social media, and business processes) to cloud environments-evidenced by the commercial success of offerings such as the Amazon EC2. In this paper, we focus on the feasibility of utilizing cloud environments for scientific workloads and workflows particularly of interest to NASA scientists and engineers. There is a wide spectrum of such technical computations. These applications range from small workstation-level computations to mid-range computing requiring small clusters to high-performance simulations requiring supercomputing systems with high bandwidth/low latency interconnects. Data-centric applications manage and manipulate large data sets such as satellite observational data and/or data previously produced by high-fidelity modeling and simulation computations. Most of the applications are run in batch mode with static resource requirements. However, there do exist situations that have dynamic demands, particularly ones with public-facing interfaces providing information to the general public, collaborators and partners, as well as to internal NASA users. In the last few months we have been studying the suitability of cloud environments for NASA's technical and scientific workloads. We have ported several applications to multiple cloud environments including NASA's Nebula environment, Amazon's EC2, Magellan at NERSC, and SGI's Cyclone system. We critically examined the performance of the applications on these systems. We also collected information on the usability of these cloud environments. In this talk we will present the results of our study focusing on the efficacy of using clouds for NASA's scientific applications.

Environic implications of lighter than air transportation

NASA Technical Reports Server (NTRS)

Horsbrugh, P.

1975-01-01

The advent of any new system of transportation must now be reviewed in the physical context and texture of the landscape. Henceforward, all transportation systems will be considered in respect of their effects upon the environment to ensure that they afford an environic asset as well as provide an economic benefit. The obligations which now confront the buoyancy engineers are emphasized so that they may respond to these ethical and environic urgencies simultaneously with routine technical development.

Physiological and ecological consequences of sleeping-site selection by the Galapagos land iguana (Conolophus pallidus)

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

Christian, K.A.; Tracy, C.R.

1984-01-01

Field observations and biophysical models were combined to analyze sleeping-site selection by Galapagos land iguanas (Conolophus pallidus). Iguanas slept in different kinds of sleeping sites during different seasons. In the coolest season (garua), adult land iguanas were found in sleeping sites that were warmer than the coolest sites available. This may be because the garua season (cool, overcast, and foggy) is a time when environmental conditions mitigate against rapid warm-up in the mornings, so lizards may regulate nighttime body temperatures so that it is easier to warm up to preferred daytime body temperatures. In the warmest season, adult iguanas weremore » found in the coolest sleeping sites available. This observation is consistent with hypotheses of voluntary hypothermia, which can be advantageous in energy conservation and in avoiding detrimental effects associated with maintenance of constant body temperatures throughout the day and night. Juvenile iguanas were found sleeping in rock crevices regardless of the ambient thermal environments. Such sites are likely to be important as refugia for this life stage, which, unlike the adult stage, is vulnerable to predation. It was concluded that selection of sleeping sites is a process that may help in avoidance of predation, optimization of body temperature at the end of the sleeping period, and reduction of metabolic costs during sleeping. The importance of some of these factors may change with the thermal milieu (e.g., season).« less

Hypoxia tolerance in coral-reef triggerfishes (Balistidae)

NASA Astrophysics Data System (ADS)

Wong, Corrie C.; Drazen, Jeffrey C.; Callan, Chatham K.; Korsmeyer, Keith E.

2018-03-01

Despite high rates of photosynthetic oxygen production during the day, the warm waters of coral reefs are susceptible to hypoxia at night due to elevated respiration rates at higher temperatures that also reduce the solubility of oxygen. Hypoxia may be a challenge for coral-reef fish that hide in the reef to avoid predators at night. Triggerfishes (Balistidae) are found in a variety of reef habitats, but they also are known to find refuge in reef crevices and holes at night, which may expose them to hypoxic conditions. The critical oxygen tension ( P crit) was determined as the point below which oxygen uptake could not be maintained to support standard metabolic rate (SMR) for five species of triggerfish. The triggerfishes exhibited similar levels of hypoxia tolerance as other coral-reef and coastal marine fishes that encounter low oxygen levels in their environment. Two species, Rhinecanthus rectangulus and R. aculeatus, had the lowest P crit ( 3.0 kPa O2), comparable to the most hypoxia-tolerant obligate coral-dwelling gobies, while Odonus niger and Sufflamen bursa were moderately tolerant to hypoxia ( P crit 4.5 kPa), and Xanthichthys auromarginatus was intermediate ( P crit 3.7 kPa). These differences in P crit were not due to differences in oxygen demand, as all the species had a similar SMR once mass differences were taken into account. The results suggest that triggerfish species are adapted for different levels of hypoxia exposure during nocturnal sheltering within the reef.

Future regional transport aircraft market, constraints, and technology stimuli

NASA Technical Reports Server (NTRS)

Harvey, W. Don; Foreman, Brent

1992-01-01

This report provides updated information on the current market and operating environment and identifies interlinking technical possibilities for competitive future commuter-type transport aircraft. The conclusions on the market and operating environment indicate that the regional airlines are moving toward more modern and effective fleets with greater passenger capacity and comfort, reduced noise levels, increased speed, and longer range. This direction leads to a nearly 'seamless' service and continued code-sharing agreements with the major carriers. Whereas the benefits from individual technologies may be small, the overall integration in existing and new aircraft designs can produce improvements in direct operating cost and competitiveness. Production costs are identified as being equally important as pure technical advances.

Physical Origins of Space Weather Impacts: Open Physics Questions

NASA Astrophysics Data System (ADS)

Lanzerotti, L. J.

2011-12-01

Beginning with the era of development of electrical telegraph systems in the early 19th century, physical processes in the space environment on the Sun, in the interplanetary medium, and around Earth have influenced the design and operations of ever-increasing and sophisticated technical systems, both in space and on the ground. Understanding of Earth's space environment has increased enormously in the last century and one-half. Nevertheless, many of the physical processes that produced effects on early cable and wireless technologies continue to plague modern-day systems. And as new technologies are developed for improved communications, surveillance, navigation, and conditions for human space flight, the solar-terrestrial environment often offers surprises to their safe, secure and uninterrupted operations. This talk will address some of the challenges that I see to the successful operations of some modern-day technical systems that are posed by significant deficiencies of understanding of physical processes operating from the Sun to the Earth.

40 CFR 280.99 - Letter of credit.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Letter of credit. 280.99 Section 280.99 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) TECHNICAL STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND OPERATORS OF UNDERGROUND STORAGE TANKS (UST) Financial Responsibility § 280.99...

Financing Higher Education: Three Case Studies in a Post-Disaster Recovery Environment

ERIC Educational Resources Information Center

Watson, Lisa M.; Melancon, Girard; Kinchen, Nancy

2008-01-01

This article identifies and articulates the varying funding streams for community technical colleges. In describing the funding issues resulting from Hurricane Katrina's destructive forces, the challenges inherent in complying with funding regulations juxtaposed with the need for fiscal flexibility in a postdisaster recovery environment are…

Creation of an Integrated Environment to Supply e-Learning Platforms with Office Automation Features

ERIC Educational Resources Information Center

Palumbo, Emilio; Verga, Francesca

2015-01-01

Over the last years great efforts have been made within the University environment to implement e-learning technologies in the standard educational practice. These learning technologies distribute online educational multimedia contents through technological platforms. Even though specific e-learning tools for technical disciplines were already…

Common Ada Programming Support Environment (APSE) Interface Set (CAIS) Implementation Validation Capability (CIVC2)

DTIC Science & Technology

1992-06-01

Paper, Version 2.0, December 1989. [Woodcock90] Gary Woodcock , Automated Generation of Hypertext Documents, CIVC Technical Report (working paper...environment setup, performance testing, assessor testing, and analysis) of the ACEC. A captive scenario example could be developed that would guide the

An Investigation of the Factors that May Predict Student Satisfaction in Online Learning Environments

ERIC Educational Resources Information Center

Featro, Susan Mary

2012-01-01

The study gathered data on learning styles, technical comfort level, age, gender, and undergraduate or graduate status to determine if these are predictors of student satisfaction in online learning environments. Student satisfaction was considered in terms of learner-content interaction, learner-instructor interaction, learner-learner…

Communicating Environment, Health, and Safety Information to Internal and External Audiences.

ERIC Educational Resources Information Center

Davis, Thomas S.

1995-01-01

Argues that today's corporation must keep informed a wide range of individuals who have a stake in environment, health, and safety issues. Describes four elements of an effective communications program for doing so: electronic media to communicate technical information, environmental and safety audits, public communications with company…

Use of Communication Resources in a Networked Collaborative Design Environment.

ERIC Educational Resources Information Center

Gay, Geri; Lentini, Marc

1995-01-01

Examines student use of a prototype networked collaborative design environment to support or augment learning about engineering design. Finds that students use the channels for a variety of activities to increase depth of communication, increase breadth of communication, and overcome technical difficulty. Suggests that students need multiple…

Building Ecology & School Design. Technical Bulletin.

ERIC Educational Resources Information Center

Maryland State Dept. of Education, Baltimore.

To better understand construction's impact, an overview of building ecology as a concept and as a decision-making model for school systems is provided. "Building ecology" is defined as the interrelationships among people, the built environment, and the natural environment. It has special relevance for school design because most of the…

Using Visualization to Motivate Student Participation in Collaborative Online Learning Environments

ERIC Educational Resources Information Center

Jin, Sung-Hee

2017-01-01

Online participation in collaborative online learning environments is instrumental in motivating students to learn and promoting their learning satisfaction, but there has been little research on the technical supports for motivating students' online participation. The purpose of this study was to develop a visualization tool to motivate learners…

75 FR 56491 - Technical Amendments for Marine Spark-Ignition Engines and Vessels

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-16

... spillage, incorporating safe recommended practices will result in a net benefit to the environment and lead... spillage, incorporating safe recommended practices will result in a net benefit to the environment and lead... portable fuel tanks to these new requirements, manufacturers working together on systems integration...

PGDnet: A New Problem-Solving Virtual Learning Environment

ERIC Educational Resources Information Center

Gomez, Emilio; Rodriguez-Marciel, Cristina

2012-01-01

The purpose of this paper was to provide information about the virtual learning environment known as PGDnet (the Spanish acronym for "Plataforma de Gestion Docente" or Educational Management Platform in English), which was developed by the innovative education group at the Technical University of Madrid known as "Nuevas metodologias…

Personnel Performance Assessment in Information Systems Outsourcing Environments

ERIC Educational Resources Information Center

Casado-Lumbreras, Cristina; Soto-Acosta, Pedro; Colomo-Palacios, Ricardo; de Pablos, Patricia Ordonez

2011-01-01

Purpose: The aim of this paper is to present a tool which uses semantic technologies for personnel performance and workplace learning assessment in outsourced information technology environments. Design/methodology/approach: The paper presents the tool from a technical perspective and introduces a use case that depicts the main features related to…

ENVIRONMENTAL EVALUATIONS. SCHOOL ENVIRONMENTS RESEARCH PUBLICATION NO. 2.

ERIC Educational Resources Information Center

LARSON, C. THEODORE

A COLLECTION OF SIX TECHNICAL PAPERS REPRESENTING AN ATTEMPT TO SUMMARIZE AND EVALUATE THE PRESENT STATE OF KNOWLEDGE CONCERNING THE VARIOUS ENVIRONMENTAL ASPECTS AFFECTING HUMAN BEHAVIOR IN GENERAL, AND LEARNING IN PARTICULAR. THE FIRST CONCERNS THE INTERACTIONS OF MAN AND HIS ENVIRONMENT. THE SECOND RELATES TO SPACE AS A COMPONENT OF…

The Technology Information Environment with Industry{trademark} system description

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

Detry, R.; Machin, G.

The Technology Information Environment with Industry (TIE-In{trademark}) provides users with controlled access to distributed laboratory resources that are packaged in intelligent user interfaces. These interfaces help users access resources without requiring the user to have technical or computer expertise. TIE-In utilizes existing, proven technologies such as the Kerberos authentication system, X-Windows, and UNIX sockets. A Front End System (FES) authenticates users and allows them to register for resources and subsequently access them. The FES also stores status and accounting information, and provides an automated method for the resource owners to recover costs from users. The resources available through TIE-In aremore » typically laboratory-developed applications that are used to help design, analyze, and test components in the nation`s nuclear stockpile. Many of these applications can also be used by US companies for non-weapons-related work. TIE-In allows these industry partners to obtain laboratory-developed technical solutions without requiring them to duplicate the technical resources (people, hardware, and software) at Sandia.« less

Coordinating activities between NOAA and other agencies.

PubMed

Fritz, A T; Buchman, M F

1997-11-01

The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the National Oil and Hazardous Substances Pollution Contingency Plan (NCP) mandate protection of public health, welfare, and the environment at Superfund hazardous waste sites. The NCP requires lead response agenciesto integrate baseline risk assessments into the remedial process that "assess threats to the environment." EPA policy statements direct regional offices to perform thorough, consistent ecological risk assessments, and stress the importance of coordination and technical consultation with the natural resource trustees. As a Federal natural trustee, the National Oceanic and Atmospheric Administration's (NOAA) role and responsibilities within the CERCLA process also are defined and mandated by Federal law. NOAA is responsible for identifying sites in the coastal zone that may affect natural resources, evaluating injury to trust resources, and providing technical advice on assessments and remedial and restoration alternatives. Statutes require lead cleanup agencies and trustee agencies to notify and coordinate with each other during CERCLA response. Over the past ten years, NOAA has gained valuable experience and technical expertise in environmental assessments and in evaluating contaminated aquatic environments. NOAA fulfills its responsibilities through an effective network of Coastal Resource Coordinators (CRCs) who can rapidly respond to local technical requirements and priorities, and coordinate effectively with technical and trustee representatives. In addition to CRCs, an interdisciplinary support group provides technical expertise in the scientific disciplines required to respond to the needs of regional activities. NOAA provides CRCs to coastal EPA regional offices for technical support, and to act as liaisons with Federal and state natural resource trustee agencies. The CRCs help EPA and other lead response agencies identify and assess risks to coastal resources from hazardous waste sites and to develop cost-effective strategies to minimize those risks. Notification of trustees of potential natural resource injuries and coordination of subsequent investigations helps Federal and state trustees to carry out their responsibilities effectively. Trustees' early involvement in the scoping of ecological risk assessments ensures that assessments and the entire remedial process adequately evaluate the risk to trust resources. Coordination throughout the process makes it easier to develop cost-effective and protective remedies that enhance the recovery of natural resources. Examples of NOAA's successful coordination and cooperative ecological risk assessments will be presented in brief case studies for both EPA and Department of Defense (DOD) lead sites.

Engineered Barrier System: Physical and Chemical Environment

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

P. Dixon

2004-04-26

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming bymore » deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.« less

Lactation accommodation in the workplace and duration of exclusive breastfeeding.

PubMed

Bai, Yeon; Wunderlich, Shahla M

2013-01-01

The purpose of this study was to assess current lactation accommodations in a workplace environment and to examine the association between the different dimensions of support and the duration of exclusive breastfeeding. A survey was conducted with employees of a higher-education institution and clients of an obstetric hospital in New Jersey. Factor analysis identified dimensions of workplace support. The dimensions were correlated with the duration of exclusive breastfeeding using Pearson's r correlation analysis. One hundred and thirteen working mothers participated in the study. The mean (SD) number of working hours of the participants was 34.3 (2.8) hours per week. Participants were primarily white (89.4%), older (mean age, 33.8 [6.0] years), highly educated (>82% above college graduate), and married (92%). Participants indicated that in their workplaces, breastfeeding was not common, breast pumps were not available, and on-site day care was not always an option. The analysis identified 4 dimensions of breastfeeding accommodation: break time, workplace environment, technical support, and workplace policy. Technical support (r = 0.71, P = .01) and workplace environment (r = 0.26, P = .01) were significantly associated with the duration of exclusive breastfeeding. Employers can strengthen technical support and workplace environment to encourage breastfeeding continuation in working mothers. New federal laws should consider specific guidelines for minimum requirements for functional lactation support to achieve comprehensive breastfeeding benefits. © 2013 by the American College of Nurse-Midwives.

Space transfer concepts and analysis for exploration missions

NASA Technical Reports Server (NTRS)

Woodcock, Gordon R.

1992-01-01

The current technical effort is part of the third phase of a broad-scoped and systematic study of space transfer concepts for human lunar and Mars missions. The study addressed the technical issues relating to the First Lunar Outpost (FLO) habitation vehicle with emphasis on the structure, power, life support system, and radiation environment for a baseline habitat with specific alternatives for the baseline.

NASA/University Conference on Aeronautics

NASA Technical Reports Server (NTRS)

1975-01-01

The proceedings of a conference on the future of aeronautics are presented. The subjects discussed include the following: (1) aeronautics and the education of the engineer, (2) technical trends in aeronautics, and (3) the role of the university in aeronautics. The technical trends in aeronautics are concerned with aircraft noise control, the effect of the aircraft on the environment, airborne electronics for automated flight, and trends in aircraft design.

Content and Language Integrated Learning in Higher Technical Education Using the "InGenio" Online Multimedia Authoring Tool

ERIC Educational Resources Information Center

Gimeno, Ana; Seiz, Rafael; de Siqueira, Jose Macario; Martinez, Antonio

2010-01-01

The future professional world of today's students is becoming a life-long learning process where they have to adapt to a changing market and an environment full of new opportunities and challenges. Thus, the development of a number of personal and professional skills, in addition to technical content and knowledge, is a crucial part of their…

Nuclear Matters. A Practical Guide

DTIC Science & Technology

2008-01-01

plutonium science and engineering. Figure 4.6 depicts LANL workers in Technical Area (TA)-55, the Los Alamos plutonium facility. LANL oversees...facility at Los Alamos to produce plutonium pits in a laboratory environment, with a capacity to produce a small number of pits per year . At that...Office of Secure Transportation (OST). Technical Advisors represent the following organizations: Los Alamos National Chair ATSD(NCB) Vice-Chair

A Study of Placing Army Requirements on Contract

DTIC Science & Technology

2016-04-01

perhaps being unable to control the external environment, has management authority over business and technical aspects of a specific program. The PM...research is the last element of the planning phase addressing both business and technical considerations. The acquisition team equips themselves with...report is the final product utilizing documented findings and supports the business strategy (DoD, Guidebook for the Acquisition of Services, 2011

The Global 2000 Report to the President: Entering the Twenty-First Century. Volume Two--The Technical Report.

ERIC Educational Resources Information Center

Council on Environmental Quality, Washington, DC.

This second volume of the Global 2000 study presents a technical report of detailed projections and analyses. It is a U.S. government effort to present a long-term global perspective on population, resources, and environment. The volume has four parts. Approximately half of the report, part one, deals with projections for the future in the areas…

The "Inverse Relationship" between Social Capital and Sport: A Qualitative Exploration of the Influence of Social Networks on the Development of Athletes

ERIC Educational Resources Information Center

Rosso, Edoardo G. F.

2015-01-01

Sport players' likelihood to fulfil their career expectations is influenced by both technical and non-technical aspects, including self-drive, self-confidence and access to high-quality coaching and to positive learning environments. Among other factors, belonging in the "right" social networks may help players to gain access to critical…

Non-technical skills evaluation in the critical care air ambulance environment: introduction of an adapted rating instrument--an observational study.

PubMed

Myers, Julia A; Powell, David M C; Psirides, Alex; Hathaway, Karyn; Aldington, Sarah; Haney, Michael F

2016-03-08

In the isolated and dynamic health-care setting of critical care air ambulance transport, the quality of clinical care is strongly influenced by non-technical skills such as anticipating, recognising and understanding, decision making, and teamwork. However there are no published reports identifying or applying a non-technical skills framework specific to an intensive care air ambulance setting. The objective of this study was to adapt and evaluate a non-technical skills rating framework for the air ambulance clinical environment. In the first phase of the project the anaesthetists' non-technical skills (ANTS) framework was adapted to the air ambulance setting, using data collected directly from clinician groups, published literature, and field observation. In the second phase experienced and inexperienced inter-hospital transport clinicians completed a simulated critical care air transport scenario, and their non-technical skills performance was independently rated by two blinded assessors. Observed and self-rated general clinical performance ratings were also collected. Rank-based statistical tests were used to examine differences in the performance of experienced and inexperienced clinicians, and relationships between different assessment approaches and assessors. The framework developed during phase one was referred to as an aeromedical non-technical skills framework, or AeroNOTS. During phase two 16 physicians from speciality training programmes in intensive care, emergency medicine and anaesthesia took part in the clinical simulation study. Clinicians with inter-hospital transport experience performed more highly than those without experience, according to both AeroNOTS non-technical skills ratings (p = 0.001) and general performance ratings (p = 0.003). Self-ratings did not distinguish experienced from inexperienced transport clinicians (p = 0.32) and were not strongly associated with either observed general performance (r(s) = 0.4, p = 0.11) or observed non-technical skills performance (r(s) = 0.4, p = 0.1). This study describes a framework which characterises the non-technical skills required by critical care air ambulance clinicians, and distinguishes higher and lower levels of performance. The AeroNOTS framework could be used to facilitate education and training in non-technical skills for air ambulance clinicians, and further evaluation of this rating system is merited.

OptiPhy, a technical-economic optimisation model for improving the management of plant protection practices in agriculture: a decision-support tool for controlling the toxicity risks related to pesticides.

PubMed

Mghirbi, Oussama; LE Grusse, Philippe; Fabre, Jacques; Mandart, Elisabeth; Bord, Jean-Paul

2017-03-01

The health, environmental and socio-economic issues related to the massive use of plant protection products are a concern for all the stakeholders involved in the agricultural sector. These stakeholders, including farmers and territorial actors, have expressed a need for decision-support tools for the management of diffuse pollution related to plant protection practices and their impacts. To meet the needs expressed by the public authorities and the territorial actors for such decision-support tools, we have developed a technical-economic model "OptiPhy" for risk mitigation based on indicators of pesticide toxicity risk to applicator health (IRSA) and to the environment (IRTE), under the constraint of suitable economic outcomes. This technical-economic optimisation model is based on linear programming techniques and offers various scenarios to help the different actors in choosing plant protection products, depending on their different levels of constraints and aspirations. The health and environmental risk indicators can be broken down into sub-indicators so that management can be tailored to the context. This model for technical-economic optimisation and management of plant protection practices can analyse scenarios for the reduction of pesticide-related risks by proposing combinations of substitution PPPs, according to criteria of efficiency, economic performance and vulnerability of the natural environment. The results of the scenarios obtained on real ITKs in different cropping systems show that it is possible to reduce the PPP pressure (TFI) and reduce toxicity risks to applicator health (IRSA) and to the environment (IRTE) by up to approximately 50 %.

Creating technical heritage object replicas in a virtual environment

NASA Astrophysics Data System (ADS)

Egorova, Olga; Shcherbinin, Dmitry

2016-03-01

The paper presents innovative informatics methods for creating virtual technical heritage replicas, which are of significant scientific and practical importance not only to researchers but to the public in general. By performing 3D modeling and animation of aircrafts, spaceships, architectural-engineering buildings, and other technical objects, the process of learning is achieved while promoting the preservation of the replicas for future generations. Modern approaches based on the wide usage of computer technologies attract a greater number of young people to explore the history of science and technology and renew their interest in the field of mechanical engineering.

Ten-Year Cross-Sectional Study of Mechanically Assisted Crevice Corrosion in 1352 Consecutive Patients With Metal-on-Polyethylene Total Hip Arthroplasty.

PubMed

Hussey, Daniel K; McGrory, Brian J

2017-08-01

Mechanically assisted crevice corrosion (MACC) in metal-on-polyethylene total hip arthroplasty (THA) is of concern, but its prevalence, etiology, and natural history are incompletely understood. From January 2003 to December 2012, 1352 consecutive THA surgeries using a titanium stem, cobalt-chromium alloy femoral head, and highly cross-linked polyethylene liner from a single manufacturer were performed. Patients were followed at 1-year and 5-year intervals for surveillance, but also seen earlier if they had symptoms. Any patient with osteolysis >1 cm (n = 3) or unexplained pain (n = 85) underwent examination, radiographs, complete blood count, erythrocyte sedimentation rate, and C-reactive protein, as well as tests for serum cobalt and chromium levels. Symptomatic MACC was present in 43 of 1352 patients (3.2%). Prevalence of MACC by year of implant ranged from 0% (0 of 61, 2003; 0 of 138, 2005) to 10.5% (17 of 162; 2009). The M/L Taper stem had a greater prevalence (4.9%) of MACC than all other Zimmer (Zimmer, Inc, Warsaw, IN) 12/14 trunnion stem types combined (1.2%; P < .001). Twenty-seven of 43 (62.8%) patients have undergone revision surgery, and 16 of 43 (37.2%) patients have opted for ongoing surveillance. Comparing symptomatic THA patients with and without MACC, no demographic, clinical, or radiographic differences were found. MACC was significantly more common in 0 length femoral heads (compared with both -3.5 mm and +3.5 mm heads). The prevalence of MACC in metal-on-polyethylene hips is higher in this cross-sectional study than previously reported. A significantly higher prevalence was found in patients with M/L Taper style stem and THA performed both in 2009 and also between 2009 and 2012 with this manufacturer. Copyright © 2017 Elsevier Inc. All rights reserved.

Outcompeted by an invader? Interference and exploitative competition between tropical house gecko (Hemidactylus mabouia) and Barbados leaf-toed gecko (Phyllodactylus pulcher) for diurnal refuges in anthropogenic coastal habitats.

PubMed

Williams, Robert; Pernetta, Angelo P; Horrocks, Julia A

2016-05-01

House geckos in the genus Hemidactylus are highly successful colonizers of regions beyond their native range, with colonization often resulting in displacement of native gecko species through competitive interactions for daytime refuge (crevices) and prey resources. We report on data collected from nighttime surveys undertaken in April-May 2014 on Barbados, West Indies, that focused on the distribution and abundance of the endemic Barbados leaf-toed gecko (Phyllodactylus pulcher) and the introduced tropical house gecko (Hemidactylus mabouia) along unlit coastal walls and among boulders in the grounds of a hotel resort. In contrast to patterns of displacement of native species by H. mabouia seen elsewhere, P. pulcher was more abundant than H. mabouia on coastal walls, whereas the latter was found in greater numbers using boulders at this site. Walls and boulders differed with regard to availability of diurnal refugia suitable for geckos, with the walls having high frequency of small crevices with openings <20 mm, and boulders offering very little cover other than the underside of the boulder itself. To investigate whether this niche separation was a result of differences in diurnal refuge use between the species, we conducted experimental trials in which geckos were allowed to select between refugia with different characteristics. Both species selected for narrower and warmer refugia, and refugia that had been previously occupied by the other species. These shared preferences for refugia type suggest that other factors underlie the niche separation observed in the field. In supporting high densities of P. pulcher, coastal walls could offer important secondary habitat by augmenting the natural cliff side habitat of this endemic gecko, a finding that could be exploited for the conservation of this candidate species for Critically Endangered classification. © 2016 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

On the relative importance of pool morphology and woody debris to distributions of shrimp in a Puerto Rican headwater stream

USGS Publications Warehouse

Pyron, M.; Covich, A.P.; Black, R.W.

1999-01-01

In this paper, we report the sizes and distributional orientation of woody debris in a headwater rainforest stream in the Luquillo Experimental Forest (LEF), Puerto Rico. We also provide results of a 4-month study of a wood addition experiment designed to increase cover for benthic macroinvertebrates (freshwater shrimp). We added branch-sized woody debris to 20 pools in three streams. We trapped four species of freshwater shrimp (two species of benthic detritivores and two predatory shrimp species) during each of the 4 months following wood additions. An analysis of pool morphology (maximum depth, surface area and volume) provided a useful predictor of shrimp abundances. In general, numbers of shrimps increased with sizes of stream pools. A repeated measures ANOVA demonstrated no effect of woody debris additions on total numbers of shrimp per pool area. Two detritivore species (Atya lanipes, a filter feeder and Xiphocaris elongata, a shredder) decreased in abundance with increased woody debris and there was no statistical relationship between woody debris additions and predators (Macrobrachium carcinus and M. crenulatum). Small woody debris additions may have altered flow velocities that were important to filter-feeding Atya at the microhabitat scale, although the overall velocities within pools were not altered by wood additions. Lower numbers of Atya and Xiphocaris in two of the three streams may result from the occurrence of two predaceous fishes (American eel and mountain mullet) and more predatory Macrobrachium in these streams. One likely interpretation of the results of this study is that the stream pools in these study reaches had sufficient habitat structure provided by numerous rock crevices (among large rocks and boulders) to provide refuge from predators. Addition of woody debris did not add significantly to the existing structure. These results may not apply to stream channels with sand and gravel substrata where crevices and undercut banks are lacking and where woody debris often plays a major role by providing structure and refuge.

A 2650-year-long record of environmental change from northern Yellowstone National Park based on a comparison of multiple proxy data

USGS Publications Warehouse

Whitlock, C.; Dean, W.; Rosenbaum, J.; Stevens, L.; Fritz, S.; Bracht, B.; Power, M.

2008-01-01

Geochemical, stable-isotope, pollen, charcoal, and diatom records were analyzed at high-resolution in cores obtained from Crevice Lake, a varved-sediment lake in northern Yellowstone National Park. The objective was to reconstruct the ecohydrologic, vegetation, and fire history of the watershed for the last 2650 years to better understand past climate variations at the forest-steppe transition. The data suggest a period of limited bottom-water anoxia, relatively wet winters, and cool springs and summers from 2650 to 2100 cal yr BP (700-150 BC). Dry warm conditions occurred between 2100 and 850-800 cal yr BP (150 BC and AD 1100-1150), when the lake was anoxic, winter precipitation was low, and summer stratification was protracted. The data are consistent with overall warmer/drier conditions during the Medieval Climate Anomaly, although they suggest a shift towards wetter winters within that period. The period from 850 to 800 cal yr BP (AD 1100-1150) to 250 cal yr BP (AD 1700) was characterized by greater water-column mixing and cooler spring/summer conditions than before. In addition, fire activity shifted towards infrequent large events and pollen production was low. From 250 to 150 cal yr BP (AD 1700-1800), winter precipitation was moderate compared to previous conditions, and the lake was again stratified, suggesting warm summers. Between 150 and 42 cal yr BP (AD 1800-1908), winter precipitation increased and spring and summer conditions became moderate. Metal pollution, probably from regional mining operations, is evident in the 1870s. Large fires occurred between ca. 1800-1880, but in general the forests were more closed than before. The Crevice Lake record suggests that the last 150 years of Yellowstone's environmental history were characterized by intermediate conditions when compared with the previous 2500 years. ?? 2007 Elsevier Ltd and INQUA.

Coastal cliffs, rock-slope failures and Late Quaternary transgressions of the Black Sea along southern Crimea

NASA Astrophysics Data System (ADS)

Pánek, Tomáš; Lenart, Jan; Hradecký, Jan; Hercman, Helena; Braucher, Règis; Šilhán, Karel; Škarpich, Václav

2018-02-01

Rock-slope failures represent a significant hazard along global coastlines, but their chronology remains poorly documented. Here, we focus on the geomorphology and chronology of giant rockslides affecting the Crimean Mountains along the Black Sea coast. Geomorphic evidence suggests that high (>100 m) limestone cliffs flanking the southern slopes of the Crimean Mountains are scarps of rockslides nested within larger deep-seated gravitational slope deformations (DSGSDs). Such pervasive slope failures originated due to lateral spreading of intensively faulted Late Jurassic carbonate blocks moving atop weak/plastic Late Triassic flysch and tuff layers. By introducing a dating strategy relying on the combination of the uranium-thorium dating (U-Th) of exposed calcareous speleothems covering the landslide scarps with the 36Cl exposure dating of rock walls, we are able to approximate the time interval between the origin of incipient crevices and the final collapse of limestone blocks that exposed the cliff faces. For the three representative large-scale rockslides between the towns of Foros and Yalta, the initiation of the DSGSDs as evidenced by the widening of crevices and the onset of speleothem accumulation was >300 ka BP, but the recent cliff morphology along the coast is the result of Late Pleistocene/Holocene failures spanning ∼20-0.5 ka BP. The exposures of rockslide scarps occurred mostly at ∼20-15, ∼8, ∼5-4 and ∼2-0.5 ka, which substantially coincide with the last major Black Sea transgressions and/or more humid Holocene intervals. Our study suggests that before ultimate fast and/or catastrophic slope failures, the relaxation of rock massifs correlative with karstification, cracks opening, and incipient sliding lasted on the order of 104-105 years. Rapid Late Glacial/Holocene transgressions of the Black Sea likely represented the last impulse for the collapse of limestone blocks and the origin of giant rockslides, simultaneously affecting the majority of the SW coast of the Crimean Peninsula.

Corrosion Damage and Wear Mechanisms in Long-Term Retrieved CoCr Femoral Components for Total Knee Arthroplasty.

PubMed

Arnholt, Christina M; MacDonald, Daniel W; Malkani, Arthur L; Klein, Gregg R; Rimnac, Clare M; Kurtz, Steven M; Kocagoz, Sevi B; Gilbert, Jeremy L

2016-12-01

Metal debris and ion release has raised concerns in joint arthroplasty. The purpose of this study was to characterize the sources of metallic ions and particulate debris released from long-term (in vivo >15 years) total knee arthroplasty femoral components. A total of 52 CoCr femoral condyles were identified as having been implanted for more than 15 years. The femoral components were examined for incidence of 5 types of damage (metal-on-metal wear due to historical polyethylene insert failure, mechanically assisted crevice corrosion at taper interfaces, cement interface corrosion, third-body abrasive wear, and inflammatory cell-induced corrosion [ICIC]). Third-body abrasive wear was evaluated using the Hood method for polyethylene components and a similar method quantifying surface damage of the femoral condyle was used. The total area damaged by ICIC was quantified using digital photogrammetry. Surface damage associated with corrosion and/or CoCr debris release was identified in 51 (98%) CoCr femoral components. Five types of damage were identified: 98% of femoral components exhibited third-body abrasive wear (mostly observed as scratching, n = 51/52), 29% of femoral components exhibited ICIC damage (n = 15/52), 41% exhibited cement interface damage (n = 11/27), 17% exhibited metal-on-metal wear after wear-through of the polyethylene insert (n = 9/52), and 50% of the modular femoral components exhibited mechanically assisted crevice corrosion taper damage (n = 2/4). The total ICIC-damaged area was an average of 0.11 ± 0.12 mm 2 (range: 0.01-0.46 mm 2 ). Although implant damage in total knee arthroplasty is typically reported with regard to the polyethylene insert, the results of this study demonstrate that abrasive and corrosive damage occurs on the CoCr femoral condyle in vivo. Copyright © 2016 Elsevier Inc. All rights reserved.

The seating mechanics of head-neck modular tapers in vitro: Load-displacement measurements, moisture, and rate effects.

PubMed

Ouellette, Eric S; Shenoy, Aarti A; Gilbert, Jeremy L

2018-04-01

The mechanically assisted crevice corrosion performance of head-neck modular tapers is a significant concern in orthopedic biomaterials. Fretting crevice corrosion processes in modular tapers are thought to be influenced by a wide array of factors including seating mechanics of the junction, hence there is a need for in vitro test methods that can assess their performance. This study presented a test method to directly measure the load-displacement seating mechanics of modular tapers and used this method to compare the seating mechanics for different tapers, moisture, seating loads and seating rates. Seating mechanics were explored whereby the instantaneous load-displacement behavior of the head seating onto the neck is captured and used to define the mechanics of seating. Two distinct taper design/material combinations were assembled wet or dry using axially applied loads (500, 1,000, 2,000, and 4,000 N) at two loading rates of 100 and 10 4  N/s (n = 5 for each condition) using a servohydraulic test frame. The results showed that pull-off strength scaled with seating load and ranged between 43% and 68% of seating load depending on sample and wetness. Tapers seated wet had higher pull-off strengths (2,200 ± 300 N) than those seated dry (1,800 ± 200 N, p < 0.05). Seating mechanics (load-displacement plots) varied due to sample type and due to wetness with differences in seating energy, seating stiffness, and seating displacement. These results show the detailed mechanics of seating during assembly and provide significant insight into the complex interplay of factors associated with even "ideal" seating (axial, quasistatic) loading. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1164-1172, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Ground Penetrating Radar, a Method for Exploration and Monitoring of Coal Fires in China

NASA Astrophysics Data System (ADS)

Gundelach, Volker

2010-05-01

Due to the climate change it is a global task to fight against gas emission of coal fires. In China exists many burning coal seams which should be extinguished. A Chinese-German initiative tries to find new technologies and solutions to control these fires. Most of the fires are close to the surface in arid areas. In that case GPR is a possible geophysical method to get detailed information about the structure of the soil. Mining activities and the burning coal are leaving voids which collapse or still exist as dangerous areas. With GPR it is possible to detect voids and clefts. Crevices are potential paths for oxygen transport from the surface to the fire. The knowledge of these structures would help to extinguish the fire. The heat of the burning coal changes the permittivity and the conductivity of the rock. This affects the radar signal and makes it possible to separate burning zones from intact zones. Monitoring of the burning zones helps to find optimal solutions for fire extinguishing strategies. Several field campaigns were made in China. One campaign was in the province Xinjiang with a 50 MHz system from Mala on a steep dipping coal seam. Other campaigns were in the Inner Mongolia with 40 MHz to 200 MHz antennae from GSSI on shallow dipping coal seams. The experiences from these measurements will be shown. The surveys were collected in rough terrain. The data from the unshielded antennae contained a lot of effects coming through the air. The limits of detecting crevices with GPR will be demonstrated. Some parts of the measurements over burning coal were influenced by strong anomalies of the magnetization. Modeling of the radar signal helps at the interpretation. Parts of the interpretation from the surveys can be validated by the outcrop of the investigated structures. A spatial visualization of the results is the basis for discussions.

R102Q mutation shifts the salt-bridge network and reduces the structural flexibility of human neuronal calcium sensor-1 protein.

PubMed

Zhu, Yuzhen; Wu, Ying; Luo, Yin; Zou, Yu; Ma, Buyong; Zhang, Qingwen

2014-11-20

Neuronal calcium sensor-1 (NCS-1) protein has a variety of different neuronal functions and interacts with multiple binding partners mostly through a large solvent-exposed hydrophobic crevice (HC). A single R102Q mutation in human NCS-1 protein was demonstrated to be associated with autism disease. Solution NMR study reported that this R102Q mutant had long-range chemical shift effects on the HC and the C-terminal tail (L3). To understand the influence of the R102Q mutation on the HC and L3 of NCS-1, we have investigated the conformational dynamics and the structural flexibility of wild type (WT) NCS-1 and its R102Q mutant by conducting extensive all-atom molecular dynamics (MD) simulations. On the basis of six independent 450 ns MD simulations, we have found that the R102Q mutation in NCS-1 protein (1) dramatically reduces the flexibility of loops L2 and L3, (2) facilitates L3 in a more extended state to occupy the hydrophobic crevice to a larger extent, (3) significantly affects the intersegment salt bridges, and (4) changes the subspace of the free energy landscape of NCS-1 protein. Analysis of the salt bridge network in both WT and the R102Q variant demonstrates that the R102Q-mutation-induced salt bridge alternations play a critical role on the reduced flexibility of L2 and L3. These results reveal the important role of salt bridges on the structural properties of NCS-1 protein and that R102Q mutation disables the dynamic relocation of C-terminus, which may block the binding of NCS-1 protein to its receptors. This study may provide structural insights into the autistic spectrum disorder associated with R102Q mutation.

Simulation experience enhances physical therapist student confidence in managing a patient in the critical care environment.

PubMed

Ohtake, Patricia J; Lazarus, Marcilene; Schillo, Rebecca; Rosen, Michael

2013-02-01

Rehabilitation of patients in critical care environments improves functional outcomes. This finding has led to increased implementation of intensive care unit (ICU) rehabilitation programs, including early mobility, and an associated increased demand for physical therapists practicing in ICUs. Unfortunately, many physical therapists report being inadequately prepared to work in this high-risk environment. Simulation provides focused, deliberate practice in safe, controlled learning environments and may be a method to initiate academic preparation of physical therapists for ICU practice. The purpose of this study was to examine the effect of participation in simulation-based management of a patient with critical illness in an ICU setting on levels of confidence and satisfaction in physical therapist students. A one-group, pretest-posttest, quasi-experimental design was used. Physical therapist students (N=43) participated in a critical care simulation experience requiring technical (assessing bed mobility and pulmonary status), behavioral (patient and interprofessional communication), and cognitive (recognizing a patient status change and initiating appropriate responses) skill performance. Student confidence and satisfaction were surveyed before and after the simulation experience. Students' confidence in their technical, behavioral, and cognitive skill performance increased from "somewhat confident" to "confident" following the critical care simulation experience. Student satisfaction was highly positive, with strong agreement the simulation experience was valuable, reinforced course content, and was a useful educational tool. Limitations of the study were the small sample from one university and a control group was not included. Incorporating a simulated, interprofessional critical care experience into a required clinical course improved physical therapist student confidence in technical, behavioral, and cognitive performance measures and was associated with high student satisfaction. Using simulation, students were introduced to the critical care environment, which may increase interest in working in this practice area.

Technical guidelines for enhancing privacy and data protection in modern electronic medical environments.

PubMed

Gritzalis, Stefanos; Lambrinoudakis, Costas; Lekkas, Dimitrios; Deftereos, Spyros

2005-09-01

Raising awareness and providing guidance to on-line data protection is undoubtedly a crucial issue worldwide. Equally important is the issue of applying privacy-related legislation in a coherent and coordinated way. Both these topics gain extra attention when referring to medical environments and, thus, to the protection of patients' privacy and medical data. Electronic medical transactions require the transmission of personal and medical information over insecure communication channels like the Internet. It is, therefore, a rather straightforward task to capture the electronic medical behavior of a patient, thus constructing "patient profiles," or reveal sensitive information related to a patient's medical history. The consequence is clearly a potential violation of the patient's privacy. We performed a risk analysis study for a Greek shared care environment for the treatment of patients suffering from beta-thalassemia, an empirically embedded scenario that is representative of many other electronic medical environments; we capitalized on its results to provide an assessment of the associated risks, focusing on the description of countermeasures, in the form of technical guidelines that can be employed in such medical environments for protecting the privacy of personal and medical information.

Wireless Robotic Communications in Urban Environments: Issues for the Fire Service

DTIC Science & Technology

2008-03-01

affect signal propagation? Do some frequencies perform better than others in specific settings? • Radio Environment: How much impact might...of responders at each scenario, the radio frequency environment for each will be examined. Link budget calculations will be performed to assess...soldiers indicated that the main technical drawbacks were the narrow field of view, poor image quality, and limited radio range. The authors concluded

Squamation and ecology of thelodonts.

PubMed

Ferrón, Humberto G; Botella, Héctor

2017-01-01

Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts. For this we use classic morphometrics and discriminant analysis to characterize the squamation patterns of a significant number of extant shark species whose ecology is well known. Multivariate analyses have defined a characteristic squamation pattern for each ecological group, thus establishing a comparative framework for inferring lifestyles in thelodonts. We then use this information to study the squamation of the currently described 147 species of thelodonts, known from both articulated and disarticulated remains. Discriminant analysis has allowed recognizing squamation patterns comparable to those of sharks and links them to specific ecological groups. Our results suggest a remarkable ecological diversity in thelodonts. A large number of them were probably demersal species inhabiting hard substrates, within caves and crevices in rocky environments or reefs, taking advantage of the flexibility provided by their micromeric squamations. Contrary to classical interpretations, only few thelodonts were placed among demersal species inhabiting sandy and muddy substrates. Schooling species with defensive scales against ectoparasites could be also abundant suggesting that social interactions and pressure of ectoparasites were present in vertebrates as early the Silurian. The presence of species showing scales suggestive of low to moderate speed and a lifestyle presumably associated with open water environments indicates adaptation of thelodonts to deep water habitats. Scale morphology suggests that some other thelodonts were strong-swimming pelagic species, most of them radiating during the Early Devonian in association with the Nekton Revolution.

Squamation and ecology of thelodonts

PubMed Central

Botella, Héctor

2017-01-01

Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts. For this we use classic morphometrics and discriminant analysis to characterize the squamation patterns of a significant number of extant shark species whose ecology is well known. Multivariate analyses have defined a characteristic squamation pattern for each ecological group, thus establishing a comparative framework for inferring lifestyles in thelodonts. We then use this information to study the squamation of the currently described 147 species of thelodonts, known from both articulated and disarticulated remains. Discriminant analysis has allowed recognizing squamation patterns comparable to those of sharks and links them to specific ecological groups. Our results suggest a remarkable ecological diversity in thelodonts. A large number of them were probably demersal species inhabiting hard substrates, within caves and crevices in rocky environments or reefs, taking advantage of the flexibility provided by their micromeric squamations. Contrary to classical interpretations, only few thelodonts were placed among demersal species inhabiting sandy and muddy substrates. Schooling species with defensive scales against ectoparasites could be also abundant suggesting that social interactions and pressure of ectoparasites were present in vertebrates as early the Silurian. The presence of species showing scales suggestive of low to moderate speed and a lifestyle presumably associated with open water environments indicates adaptation of thelodonts to deep water habitats. Scale morphology suggests that some other thelodonts were strong-swimming pelagic species, most of them radiating during the Early Devonian in association with the Nekton Revolution. PMID:28241029

Relationship between intraoperative non-technical performance and technical events in bariatric surgery.

PubMed

Fecso, A B; Kuzulugil, S S; Babaoglu, C; Bener, A B; Grantcharov, T P

2018-03-30

The operating theatre is a unique environment with complex team interactions, where technical and non-technical performance affect patient outcomes. The correlation between technical and non-technical performance, however, remains underinvestigated. The purpose of this study was to explore these interactions in the operating theatre. A prospective single-centre observational study was conducted at a tertiary academic medical centre. One surgeon and three fellows participated as main operators. All patients who underwent a laparoscopic Roux-en-Y gastric bypass and had the procedures captured using the Operating Room Black Box ® platform were included. Technical assessment was performed using the Objective Structured Assessment of Technical Skills and Generic Error Rating Tool instruments. For non-technical assessment, the Non-Technical Skills for Surgeons (NOTSS) and Scrub Practitioners' List of Intraoperative Non-Technical Skills (SPLINTS) tools were used. Spearman rank-order correlation and N-gram statistics were conducted. Fifty-six patients were included in the study and 90 procedural steps (gastrojejunostomy and jejunojejunostomy) were analysed. There was a moderate to strong correlation between technical adverse events (r s  = 0·417-0·687), rectifications (r s  = 0·380-0·768) and non-technical performance of the surgical and nursing teams (NOTSS and SPLINTS). N-gram statistics showed that after technical errors, events and prior rectifications, the staff surgeon and the scrub nurse exhibited the most positive non-technical behaviours, irrespective of operator (staff surgeon or fellow). This study demonstrated that technical and non-technical performances are related, on both an individual and a team level. Valuable data can be obtained around intraoperative errors, events and rectifications. © 2018 BJS Society Ltd Published by John Wiley & Sons Ltd.

Interprofessional non-technical skills for surgeons in disaster response: a qualitative study of the Australian perspective.

PubMed

Willems, Anneliese; Waxman, Buce; Bacon, Andrew K; Smith, Julian; Peller, Jennifer; Kitto, Simon

2013-03-01

Interprofessional non-technical skills for surgeons in disaster response have not yet been developed. The aims of this study were to identify the non-technical skills required of surgeons in disaster response and training for disaster response and to explore the barriers and facilitators to interprofessional practice in surgical teams responding to disasters. Twenty health professionals, with prior experience in natural disaster response or education, participated in semi-structured in-depth interviews. A qualitative matrix analysis design was used to thematically analyze the data. Non-technical skills for surgeons in disaster response identified in this study included skills for austere environments, cognitive strategies and interprofessional skills. Skills for austere environments were physical self-care including survival skills, psychological self-care, flexibility, adaptability, innovation and improvisation. Cognitive strategies identified in this study were "big picture" thinking, situational awareness, critical thinking, problem solving and creativity. Interprofessional attributes include communication, team-player, sense of humor, cultural competency and conflict resolution skills. "Interprofessionalism" in disaster teams also emerged as a key factor in this study and incorporated elements of effective teamwork, clear leadership, role adjustment and conflict resolution. The majority of participants held the belief that surgeons needed training in non-technical skills in order to achieve best practice in disaster response. Surgeons considerring becoming involved in disaster management should be trained in these skills, and these skills should be incorporated into disaster preparation courses with an interprofessional focus.

Technical efficiency in milk production in underdeveloped production environment of India*.

PubMed

Bardhan, Dwaipayan; Sharma, Murari Lal

2013-12-01

The study was undertaken in Kumaon division of Uttarakhand state of India with the objective of estimating technical efficiency in milk production across different herd-size category households and factors influencing it. Total of 60 farm households having representation from different herd-size categories drawn from six randomly selected villages of plain and hilly regions of the division constituted the ultimate sampling units of the study. Stochastic frontier production function analysis was used to estimate the technical efficiency in milk production. Multivariate regression equations were fitted taking technical efficiency index as the regressand to identify the factors significantly influencing technical efficiency in milk production. The study revealed that variation in output across farms in the study area was due to difference in their technical efficiency levels. However, it was interesting to note that smallholder producers were more technically efficient in milk production than their larger counterparts, especially in the plains. Apart from herd size, intensity of market participation had significant and positive impact on technical efficiency in the plains. This provides definite indication that increasing the level of commercialization of dairy farms would have beneficial impact on their production efficiency.

The Effects of Podcasting on Student Perceptions of Community within the Online Learning Environment

ERIC Educational Resources Information Center

Ferguson, Larry A.

2010-01-01

This study examined the effects of using podcasts as a medium of communication toward affecting student perception of community within the online learning environment. A control and treatment group comparison design was employed with 184 online undergraduate students selected through purposive sampling at Ashland Community and Technical College.…

A Study of Measures of Classroom Learning Environments. Technical Report Number 4.

ERIC Educational Resources Information Center

Cichon, Donald J.; Olson, George E.

This study deals with the following topics: (1) the extent to which three different learning environment instruments and their underlying conceptual framework are empirically related, and (2) the extent to which intensive observation of classrooms aids in the interpretation of instruments' characterizations of a class. In the first part of the…

Policy Choices in Vocational Education [and] Technical Appendix.

ERIC Educational Resources Information Center

Institute for the Future, Menlo Park, CA.

This report examines the impact of changes in the vocational education environment that are likely to be important to policymakers over the next fifteen years. It contains forecasts of a number of trends that will be of significance to vocational educators, an analysis of the policy implications of those trends in the education environments, and…

40 CFR 35.4070 - How can my group spend TAG money?

Code of Federal Regulations, 2012 CFR

2012-07-01

... grant; and/or (3) Provide one-time health and safety training for your technical advisor to gain site... 40 Protection of Environment 1 2012-07-01 2012-07-01 false How can my group spend TAG money? 35.4070 Section 35.4070 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL...

Students' Reaction to WebCT: Implications for Designing On-Line Learning Environments

ERIC Educational Resources Information Center

Osman, Mohamed Eltahir

2005-01-01

There is a growing number of web-based and web-assisted course development tools and products that can be used to create on-line learning environment. The utility of these products, however, varies greatly depending on their feasibility, prerequisite infrastructure, technical features, interface, and course development and management tools. WebCT…

FAA Center of Excellence for Alternative Jet Fuels & Environment : Annual Technical Report : December, 2016 : For the period September 13, 2013 - September 30, 2015

DOT National Transportation Integrated Search

2015-12-01

This report covers the period between the initial establishment of the FAA Center of Excellence for Alternative Jet Fuels and Environment on September 13, 2013 through September 30, 2015. The Center was established by the authority of FAA solicitatio...

Effects of Head Up Display Symbology Lag on Recovery from Inadvertent Instrument Meteorological Conditions: Performance Costs

DTIC Science & Technology

2006-06-01

decrements in system fidelity or mismatches in the constructed environment when it does not closely approximate the real environment (Hix and Gabbard , 2002...using moving-aircraft and moving-horizon attitude indicators. Washington, DC: FAA, Technical Report FAA-AM-73-9. Hix D., and Gabbard , J.L. 2002

Send Students Anywhere without Leaving the Classroom: Virtual Reality in CTE

ERIC Educational Resources Information Center

Ausburn, Floyd B.; Ausburn, Lynna J.

2008-01-01

Students in career and technical education (CTE) programs have many environments they need to discover, explore, and understand. For CTE teachers, transporting their students to these environments can be difficult, dangerous, or even impossible. However, there is now a way to take students on location anywhere without leaving the classroom.…

Sustaining a Healthy Environment: Training Guides for the Head Start Learning Community.

ERIC Educational Resources Information Center

Bowman (James) Associates, San Francisco, CA.

Exploring and working with environmental issues can be exciting and enriching for Head Start staff. The goal of the technical guide is to broaden Head Start staff members' understanding of the natural environment so they can better incorporate environmental enrichment and environmental protection into their programs. The guide is organized into…

Treating the Healthcare Workforce Crisis: A Prescription for a Health Informatics Curriculum

ERIC Educational Resources Information Center

Campbell, S. Matt; Pardue, J. Harold; Longenecker, Herbert E., Jr.; Barnett, H. Les; Landry, Jeffrey P.

2012-01-01

A serious need exists for information systems workers who have an understanding of the healthcare environment. Traditional information systems degree programs do not adequately prepare students to enter the healthcare environment. In this paper, we propose a curriculum for a baccalaureate health informatics degree that combines the technical and…

Fifth International Symposium on Liquid Space Propulsion

NASA Technical Reports Server (NTRS)

Garcia, R. (Compiler)

2005-01-01

Contents include the fiollowing: Theme: Life-life Combustion Devices Technology. Technical Sessions: International Perspectives. System Level Effects. Component Level Processes. Material Considerations. Design Environments -- Predictions. Injector Design Technology. Design Environments -- Measurements. Panel Discussion: Views on future research and development needs and Symposium observations. Aquarium Welcome and Southern Belle Riverboat Recognition Banquet evening events.

Some Technical Implications of Distributed Cognition on the Design on Interactive Learning Environments.

ERIC Educational Resources Information Center

Dillenbourg, Pierre

1996-01-01

Maintains that diagnosis, explanation, and tutoring, the functions of an interactive learning environment, are collaborative processes. Examines how human-computer interaction can be improved using a distributed cognition framework. Discusses situational and distributed knowledge theories and provides a model on how they can be used to redesign…

Walk, Fly, or Teleport to Learning: Virtual Worlds in the Classroom

ERIC Educational Resources Information Center

Yoder, Maureen Brown

2009-01-01

For educators looking for new ways to engage their students, multiuser virtual environments (MUVEs) offer a great opportunity for creative teaching and learning. MUVEs teach students social, technical, and practical life skills in a setting that is engaging and playful. One might be surprised how much these virtual environments teach students…

An Overview of the Space Environments and Spacecraft Effects Organization Concept

NASA Technical Reports Server (NTRS)

Edwards, David L.; Burns, Howard D.; Garrett, Henry B.; Miller, Sharon K.; Peddie, Darilyn; Porter Ron; Spann, James F.; Xapsos, Michael A.

2012-01-01

The National Aeronautics and Space Administration (NASA) is embarking on a course to expand human presence beyond Low Earth Orbit (LEO) while also expanding its mission to explore our Earth, and the solar system. Destinations such as Near Earth Asteroids (NEA), Mars and its moons, and the outer planets are but a few of the mission targets. Each new destination presents an opportunity to increase our knowledge on the solar system and the unique environments for each mission target. NASA has multiple technical and science discipline areas specializing in specific space environments fields that will serve to enable these missions. To complement these existing discipline areas, a concept is presented focusing on the development of a space environment and spacecraft effects (SESE) organization. This SESE organization includes disciplines such as space climate, space weather, natural and induced space environments, effects on spacecraft materials and systems, and the transition of research information into application. This space environment and spacecraft effects organization will be composed of Technical Working Groups (TWG). These technical working groups will survey customers and users, generate products, and provide knowledge supporting four functional areas: design environments, engineering effects, operational support, and programmatic support. The four functional areas align with phases in the program mission lifecycle and are briefly described below. Design environments are used primarily in the mission concept and design phases of a program. Environment effects focuses on the material, component, sub-system, and system-level response to the space environment and include the selection and testing to verify design and operational performance. Operational support provides products based on real time or near real time space weather to mission operators to aid in real time and near-term decision-making. The programmatic support function maintains an interface with the numerous programs within NASA, other federal government agencies, and the commercial sector to ensure that communications are well established and the needs of the programs are being met. The programmatic support function also includes working in coordination with the program in anomaly resolution and generation of lessons learned documentation. The goal of this space environment and spacecraft effects organization is to develop decision-making tools and engineering products to support all mission phases from mission concept through operations by focusing on transitioning research to application. Products generated by this space environments and effects application are suitable for use in anomaly investigations. This paper will describe the scope and purpose of the space environments and spacecraft effects organization and describe the TWG's and their relationship to the functional areas.

Defense of Defense Human Factors Engineering Technical Advisory Group Meeting Summary

DTIC Science & Technology

2012-07-01

Survivability ( Plaga ) • Wright, N; OSD and DSOC Helicopter Seating Studies Zehner, G; An Overview of USAF Anthropometry Plaga , J & Hill; SAFE Association...predictions. – 1230 - 1430 Standardization - 1472H (Poston) – 1230 - 1430 Human Factors in Extreme Environments & SS ( Plaga ) • Ganey, HCN...Classification (Personnel) LT Chris Foster Dr. Hector Acosta System Safety/Health Hazards/ Survivability (SS/HH/Sv) Mr. John Plaga Technical Society

Contract Source Selection: An Analysis of Lowest Price Technically Acceptable and Tradeoff Strategies

DTIC Science & Technology

2016-06-01

thorough market research, acquisition professionals must decide at an early stage which source selection strategy (lowest price technically...minimizing risk and ensuring best value for all stakeholders. On the basis of thorough market research, acquisition professionals must decide at an early...price-based, market -driven environment from requirements development through properly disposal. Source selection must be 8 made on a ‘best value

A Research Program in Computer Technology. 1987 Annual Technical Report

DTIC Science & Technology

1990-07-01

TITLE (Indcle Security Clanificstion) 1987 Annual Technical Report: *A Research Program in Computer Technology (Unclassified) 12. PERSONAL AUTHOR(S) IS...distributed processing, survivable networks 17. NCE: distributed processing, local networks, personal computers, workstation environment 18. SC Dev...are the auw’iors and should not be Interpreted as representIng the official opinion or policy of DARPA, the U.S. Government, or any person or agency

Building Communities of Engineers to Share Technical Expertise

NASA Technical Reports Server (NTRS)

Topousis, Daria E.; Dennehy, Cornelius J.; Fesq, Lorraine M.

2012-01-01

Developed by the core community to describe our vision of an approach to ensure a sufficiently technically advanced and affordable AR&D technology base is available to support future NASA missions. The goal of this strategy is to create an environment exploiting reusable technology elements for an AR&D system design and development process which is: a) Lower-Risk. b) More Versatile/Scalable. c) Reliable & Crew-Safe. d) More Affordable.

Competencies for government veterinary services of the future: Summary of ISVEE 14 Yucatan 2015 roundtable discussion.

PubMed

Stärk, Katharina D C; Goncalves, Vitor S P; McCluskey, Brian J; Pinto, Julio; Tsutsui, Toshiyuki; Gibbens, Jane

2017-02-01

This short communication summarizes the strengths and weaknesses of current organisational structures in government veterinary services, as well as future technical, financial and societal challenges and related necessary competencies for government veterinary services of the future as discussed by an expert panel at ISVEE2015. First, participating representatives of veterinary services of diverse geographical backgrounds and statements from the audience confirmed that non-technical skills such as ability to work in teams, adaptability to new environments and situations, social and communication skills are increasingly seen as important. The second challenge faced by veterinary services is related to capacity issues, i.e. to have enough manpower to plan and deliver according to legislation in a period of shrinking budgets. New and emerging diseases can result in sudden, massive increases in the workload of veterinary services. Technical complexity has also increased for some hazards. Staff skills in veterinary services therefore need to be continuously updated, and it is essential to establish cross technical collaboration with other sectors including food safety, public health and environment. ISVEE conferences were seen as an opportunity to provide a global platform to develop skills needed by veterinary services, now and in the future. Copyright © 2016 Elsevier B.V. All rights reserved.

CRRES combined radiation and release effects satellite program

NASA Technical Reports Server (NTRS)

Giles, B. L. (Compiler); Mccook, M. A. (Compiler); Mccook, M. W. (Compiler); Miller, G. P. (Compiler)

1995-01-01

The various regions of the magnetosphere-ionosphere system are coupled by flows of charged particle beams and electromagnetic waves. This coupling gives rise to processes that affect both technical and non-technical aspects of life on Earth. The CRRES Program sponsored experiments which were designed to produce controlled and known input to the space environment and the effects were measured with arrays of diagnostic instruments. Large amounts of material were used to modify and perturb the environment in a controlled manner, and response to this was studied. The CRRES and PEGSAT satellites were dual-mission spacecraft with a NASA mission to perform active chemical-release experiments, grouped into categories of tracer, modification, and simulation experiments. Two sounding rocket chemical release campaigns completed the study.

An Internet of Things platform architecture for supporting ambient assisted living environments.

PubMed

Tsirmpas, Charalampos; Kouris, Ioannis; Anastasiou, Athanasios; Giokas, Kostas; Iliopoulou, Dimitra; Koutsouris, Dimitris

2017-01-01

Internet of Things (IoT) is the logical further development of today's Internet, enabling a huge amount of devices to communicate, compute, sense and act. IoT sensors placed in Ambient Assisted Living (AAL) environments, enable the context awareness and allow the support of the elderly in their daily routines, ultimately allowing an independent and safe lifestyle. The vast amount of data that are generated and exchanged between the IoT nodes require innovative context modeling approaches that go beyond currently used models. Current paper presents and evaluates an open interoperable platform architecture in order to utilize the technical characteristics of IoT and handle the large amount of generated data, as a solution to the technical requirements of AAL applications.

Efficiency in the European agricultural sector: environment and resources.

PubMed

Moutinho, Victor; Madaleno, Mara; Macedo, Pedro; Robaina, Margarita; Marques, Carlos

2018-04-22

This article intends to compute agriculture technical efficiency scores of 27 European countries during the period 2005-2012, using both data envelopment analysis (DEA) and stochastic frontier analysis (SFA) with a generalized cross-entropy (GCE) approach, for comparison purposes. Afterwards, by using the scores as dependent variable, we apply quantile regressions using a set of possible influencing variables within the agricultural sector able to explain technical efficiency scores. Results allow us to conclude that although DEA and SFA are quite distinguishable methodologies, and despite attained results are different in terms of technical efficiency scores, both are able to identify analogously the worst and better countries. They also suggest that it is important to include resources productivity and subsidies in determining technical efficiency due to its positive and significant exerted influence.

Natural Environments Definition for Design

NASA Technical Reports Server (NTRS)

Justh, H. L.; Altino, K. M.; Decker, R. K.; Koehler, H. M.; Leahy, F. B.; Minow, J. I.; Roberts, B. C.; Suggs, R. M.; Suggs, R. J.; White, P. W.;

Comparing Acquisition Strategies: Open Architecture versus Product Lines

DTIC Science & Technology

2010-04-30

software • New SOW language for accepting software deliveries – Enables third-party reuse • Additional SOW language regarding conducting software code walkthroughs and for using integrated development environments ...change the business environment must be the primary factor that drives the technical approach. Accordingly, there are business case decisions to be...elements of a system design should be made available to the customer to observe throughout the design process. Electronic access to the design environment

Chemistry, Toxicity, and Bioavailability of Copper and its Relationship to Regulation in the Marine Environment

DTIC Science & Technology

1998-11-01

The majority (70%) of commercial ship hulls still use tributyltin ( TBT ) coatings, which also contain approximately 30% to 40% copper. The Navy spends...TECHNICAL DOCUMENT 3044 November 1998 Chemistry, Toxicity , and Bioavailability of Copper and Its Relationship to Regulation in the Marine Environment...participated in a Workshop on Chemistry, Toxicity , and Bioavailability of Copper and Its Relationship to Regulation in the Marine Environment. The goal

Advancements in Distributed Learning (ADL) Environment in Support of Transformation

DTIC Science & Technology

2017-01-01

REPORT TR-HFM-212 Advancements in Distributed Learning (ADL) Environment in Support of Transformation (Progrès en apprentissage distribué (ADL) à...l’appui de la transformation ) This report documents the findings of Task Group 212. The primary objective of this Task Group was to explore an agile...STO TECHNICAL REPORT TR-HFM-212 Advancements in Distributed Learning (ADL) Environment in Support of Transformation (Progrès en apprentissage

Ecological generalism and behavioural innovation in birds: technical intelligence or the simple incorporation of new foods?

PubMed

Ducatez, Simon; Clavel, Joanne; Lefebvre, Louis

2015-01-01

Generalist species are more successful than specialists in anthropogenically modified environments or in environments in which they have been introduced, but the nature of the link between generalism and establishment success is unclear. A higher feeding innovation rate has previously been reported in habitat generalist birds from North America. By allowing them to exploit new resources, this higher feeding innovation rate might explain the generalists' advantage. This result might be due to generalists being more likely to find new resources because they are exposed to more diverse environmental conditions. Alternatively, they might differ from specialists in other traits, in particular cognitive skills that might allow them to innovate more complex food searching and handling techniques. To test these hypotheses, we separated avian feeding innovations into a 'technical' (novel searching and handling behaviour) and a 'food type' (incorporation of a new food in a species' diet) category. Technical innovations, but not food type innovations, have previously been shown to correlate with avian brain size, suggesting they reflect cognitive ability. We used a world-wide data base of 2339 feeding innovations recorded in the literature, covering a total of 765 avian species and assessed the correlations between brain size and feeding innovation rates on one side and habitat and diet generalism on the other. Habitat generalism was positively related with food type innovation rate, but not technical innovation rate or brain size. This suggests that habitat generalist species are more likely to incorporate new food types in their diet because of higher chances to find new food resources in their environment, or of a higher opportunism, but not enhanced cognitive skills. In contrast, diet generalist species had higher food type and technical innovation rates, as well as larger brains, suggesting that cognitive skills might help species expand their diet breadth or that an increase in diet breadth might favour the evolution of enhanced cognitive abilities. Our results provide new insights into the nature of the generalists' advantage in the face of environmental changes, and suggest that dietary and habitat generalism are different, but convergent, routes to feeding flexibility and adaptation to changed environments. © 2014 The Authors. Journal of Animal Ecology © 2014 British Ecological Society.

PFC Decontamination of a Metal Surface and the Recycling of a Spent PFC Solution

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

Jung, C.H.; Won, H.J.; Oh, W.Z.

2006-07-01

PFC (per-fluorocarbon) ultrasonic decontamination behavior of loosely contaminated metal specimens such as a plate, pipe, welding and a crevice specimen in a mixed solution of PFC and an anionic surfactant was investigated. Perfluoroheptane (C{sub 7}F{sub 16}) was used as a PFC ultrasonic media. The contaminants were completely removed for almost all of the tested specimens except for the longest pipe length specimen. For the 6-cm long specimen, 98.5 % of the contaminants were removed. For the recycling of the PFC solution, a distillation test for the spent PFC solution was also performed. The results show that 97.5 % of themore » PFC was recycled without a loss of the decontamination efficiency. (authors)« less

Dynamics and distribution of black abalone populations at San Nicolas Island

USGS Publications Warehouse

VanBlaricom, Glenn R.; Hochberg, F.G.

1993-01-01

Dense populations of black abalones (Haliotis cracherodii Leach) were monitored in permanent intertidal plots at nine sites on San Nicolas Island from 1981 through 1990. Densities were essentially constant at all four sites along the north shore of the island throughout the study period. Densities at five sites along the south shore were more variable, possibly reflecting asynchronous variation in recruitment, mortality resulting from wave disturbance, and removal by people. Temporal variation of abalone densities apparently was not influenced by sea otters or abalone withering syndrome during this study. Abalones were strongly aggregated in space. Highest densities occurred in areas of irregular substrata, apparently as a result of preference for crevices and vertical faces. The locations of dense patches were persistent in time.

Passive Films, Surface Structure and Stress Corrosion and Crevice Corrosion Susceptibility. Part I. A Qualitative Ellipsometric-Electrochemical Approach for the Study of Film Growth under Organic Coatings. Part II. Hydrogen Interactions with Stressed Titanium-Palladium Alloys and Stressed Vanadium Explored with Field Ion Microscopy.

DTIC Science & Technology

1980-08-01

vs. time for Fe with collodion in 0.05 N NaCl. 8. A, 6 p, pH and 0Fe vs. time for Fe with collodion and CrO 4 " 2 islands in 0.05 N NaCl. REFERENCES...hydrogen embrittlement with the field ion microscope, and to compare the results with those previously obtained with pure titanium [ 4 ]. 2.2. Specimen...percent pure, and was used in the previous field ion microscopy study of titanium [ 4 ], where it was found that strain annealing titanium wire markedly

Local Foods, Local Places

EPA Pesticide Factsheets

The Local Foods, Local Places technical assistance program protects human health and the environment, spurs revitalization, increases access to healthy foods, and creates economic opportunities by promoting local foods.

75 FR 71414 - Information Collection Activity; Comment Request

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-23

..., including through the use of appropriate automated, electronic, mechanical, or other technological... endangering the environment. Rural Development provides financial and technical assistance to help communities...

The Development of Nanotechnologies and Advanced Materials Industry in Science and Entrepreneurship: Socioeconomic and Technical Indicators. A Case Study of Latvia (Part Two)

NASA Astrophysics Data System (ADS)

Geipele, I.; Geipele, S.; Staube, T.; Ciemleja, G.; Zeltins, N.

2016-10-01

Part two of the in-depth scientific study clarifies the significant social and technical indicators of the development of nano-field at the macro, micro, and meso development levels of the economic environment in Latvia in the framework of the given theme. The analytical assessment of numerical change in socioeconomic and technical factors clearly demonstrates the interaction of nano-field with the development of science and manufacture, as found out in the study. The identified indicators are proposed to use for research, comparison and implementation in any other country of the world.

Research to Advance the Development of River Information Services (RIS) Technologies

DTIC Science & Technology

2016-12-01

RIS implementation in Europe. Both the legal as well as the technical framework are been presented and analyzed. Special attention has been given to...and legal environments on both continents and take into account the organ- izational situation in the U.S. and the existing capabilities. Research...rective” Europe has set the legal and technical framework which guarantees harmonized implementation of RIS in all member states as well as a minimum

Mine Burial Assessment State-of the Art in Prediction and Modeling Workshop and Initiation of Technical Program

DTIC Science & Technology

2000-09-30

Burial Assessment State-of-the Art Science , Technology, and Modeling. A Review of Coastal Research, Modeling, and Naval Operational Needs in Shallow Water...the ONR Mine Burial Prediction Program are summarized below. 1) Completed comprehensive technical reports: a. Mine Burial Assessment, State-of-the Art ... Science , Technology, and Modeling. A review of Coastal Research, Modeling, and Naval Operational Needs in Shallow Water Environments with

A Research Program in Computer Technology. 1986 Annual Technical Report

DTIC Science & Technology

1989-08-01

1986 (Annual Technical Report I July 1985 - June 1986 A Research Program in Computer Technology ISI/SR-87-178 U S C INFORMA-TION S C I EN C ES...Program in Computer Technology (Unclassified) 12. PERSONAL AUTHOR(S) 151 Research Staff 13a. TYPE OF REPORT 113b. TIME COVERED 14 DATE OF REPORT (Yeer...survivable networks 17. distributed processing, local networks, personal computers, workstation environment 18. computer acquisition, Strategic Computing 19

Laser geodynamic satellite thermal/optical/ vibrational analyses and testing. Volume 2: Technical report, book 1. [retroreflector design

NASA Technical Reports Server (NTRS)

1974-01-01

The results of the LAGEOS thermal/optical/vibrational analysis and test program are reported. Through analyses and tests it is verified that the MSFC LAGEOS design provides a retroreflector thermal environment which maintains acceptable retroflector internal thermal gradients. The technical results of the study, organized by the major task areas are presented. The interrelationships of the major tasks are described and the major decisions are identified.

Socio-Technical Dimensions of an Outdoor Mobile Learning Environment: A Three-Phase Design-Based Research Investigation

ERIC Educational Resources Information Center

Land, Susan M.; Zimmerman, Heather Toomey

2015-01-01

This design-based research project examines three iterations of Tree Investigators, a learning environment designed to support science learning outdoors at an arboretum and nature center using mobile devices (iPads). Researchers coded videorecords and artifacts created by children and parents (n = 53) to understand how both social and…

The Time Factor: Leveraging Intelligent Agents and Directed Narratives in Online Learning Environments

ERIC Educational Resources Information Center

Jones, Greg; Warren, Scott

2009-01-01

Using video games, virtual simulations, and other digital spaces for learning can be a time-consuming process; aside from technical issues that may absorb class time, students take longer to achieve gains in learning in virtual environments. Greg Jones and Scott Warren describe how intelligent agents, in-game characters that respond to the context…

Counting on Energy. Project E3 (Energy, Economics, and the Environment).

ERIC Educational Resources Information Center

Tully, Randolph R., Jr.; Reese, D. Chris

Five units are designed to provide an opportunity for in-depth, technical analysis in the fields of energy, economics, and the environment. In an effort to move upper elementary and secondary students beyond general awareness, activities call for the application of numbers where typically only vague generalities are discussed. Within each chapter,…

Bioenvironmental Engineering Guide to Beryllium

DTIC Science & Technology

2017-07-26

Health Dept Consultative Services Division 2510 Fifth St., Bldg. 840 Wright-Patterson AFB, OH 45433-7913 DISTRIBUTION STATEMENT A. Approved for...Environ Health Dept Chair, Occup & Environ Health Dept This report is published in the interest of scientific and technical...UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) USAF School of Aerospace Medicine Occupational & Environmental Health Dept

40 CFR 35.4070 - How can my group spend TAG money?

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false How can my group spend TAG money? 35.4070 Section 35.4070 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY GRANTS AND OTHER FEDERAL ASSISTANCE STATE AND LOCAL ASSISTANCE Grants for Technical Assistance What Tags Can Pay For § 35.4070 How can...

Designing for Discovery: Interactive Multimedia Learning Environments at Bank Street College. Technical Report No. 15.

ERIC Educational Resources Information Center

Wilson, Kathleen; Tally, William

This report discusses "multimedia" instruction as it applies to successful learning environments at Bank Street College of Education (New York), ranging from pre-electronic to electronic. In four of the interviews detailed, a Bank Street College professor, researcher, and two Bank Street School for Children teachers offer different perspectives…

Recommendations for Accessibility Standards for Children's Environments: Task Five. Technical Report.

ERIC Educational Resources Information Center

North Carolina State Univ., Raleigh. Center for Accessible Housing.

The purpose of this project was to develop and present a set of recommendations for supplements to the existing Uniform Federal Accessibility Standards (UFAS) that would apply to environments used by children with physical disabilities. The work was subdivided into six phases: (1) review of selected codes, standards and guidelines; (2) review of…