bluuebunny/crossref_metadata_2025 huggingface dataset:
Multidisciplinary Simulation in Pediatric Critical Care: The Death of a Child
Authors: Youngblood Amber Q. , Zinkan J. Lynn , Tofil Nancy M. , White Marjorie Lee
Published: June 2012

Health care providers are trained to care for the living. They may complete their education and enter the workforce without ever experiencing the death of a patient. Inexperience with the different roles of the multidisciplinary health care team is common. Moreover, the death of a child has a profound effect on parents and staff. In such situations, the expertise of the multidisciplinary team can make a difference. A multidisciplinary education project that uses high-fidelity simulation based on pediatric death and dying was developed to provide an experience during which health care practitioners could practice communicating with families about the death of their child and dealing with different grief reactions.
Contrast-Induced Nephropathy: Nursing Implications
Authors: Isaac Susan
Published: June 2012

Contrast-induced nephropathy is a major adverse event that occurs during studies that require contrast medium. Almost 10% of all hospital-acquired instances of renal insufficiency are directly attributed to contrast material, with significantly higher mortality and morbidity than cases that do not involve contrast material. Contrast material causes an acceleration of the renal vasoconstrictive response, which results in a cascade of events that affect the vasoregulatory system. Multiple prophylactic measures must be instituted when considering a patient for a contrast study. Critical care nurses are pivotal in identifying patients’ risk factors and potential nephrotoxic agents in order to avoid contrast-induced nephropathy. This article outlines the pathophysiology and definitions of normal kidney function, nephropathy, and chronic kidney disease.
Tend and Befriend in the Intensive Care Unit
Authors: Ganz Freda DeKeyser
Published: June 2012

Stress is a common phenomenon in the intensive care unit for both patients and nurses. Critical care nurses may experience many forms of stress, including physical, psychological, and moral stress or distress. The physiological stress response traditionally associated with the hypothalamic-pituitary-adrenal axis has been expanded to include a new model, called tend and befriend, that has been linked to females of different species, including humans. Studies have shown that stress also affects immune function. Although commonly associated with adverse outcomes, stress can lead to personal growth. The tend and befriend strategy is an intervention that was developed to help nurses increase their ability to grow from stressful situations, especially those related to moral distress.
Effect of percutaneous transthoracic lung biopsy on oxidative metabolism in sheep
Authors: Silva Andreza A. , Ferreira Danilo O.L. , Santarosa Bianca P. , Dias Adriano , Damasceno Débora C. , Gonçalves Roberto C.
Published: June 2012

This study aimed to assess the effect of percutaneous transthoracic lung biopsy on the oxidative metabolism of sheep by measuring the oxidative stress markers of superoxide dismutase (SOD), total glutathione (GSH-t), peroxidase (GSH-Px) and thiobarbituric acid reactive substances (TBARS) in the red cells of these animals. Blood samples were collected from 20 clinically healthy sheep prior to, and 30 min after, percutaneous transthoracic lung biopsy. After biopsy, there was a significant decrease (p 0.05) in SOD and GSH-Px activity, with no significant change (p ≥ 0.05) in GSH-t and TBARS concentrations. These results showed that percutaneous transthoracic lung biopsy did not significantly affect the oxidative metabolism of sheep 30 min after the procedure, which may be used widely in this species without causing serious tissue damage.
Yield variability in Phalaris canariensis L. due to seeding date, seeding rate and nitrogen fertilizer
Authors: May W. E. , Lafond G. P. , Gan Y. T. , Hucl P. , Holzapfel C. B. , Johnston A. M. , Stevenson C.
Published: June 2012

May, W. E., Lafond, G. P., Gan, Y. T., Hucl, P., Holzapfel, C. B., Johnston, A. M. and Stevenson, C. 2012. Yield variability in Phalaris canariensis L. due to seeding date, seeding rate and nitrogen fertilizer. Can. J. Plant Sci. 92: 651–669. Concern over the year-to-year and field-to-field variability in grain yield has consistently been expressed by annual canarygrass growers in Saskatchewan. The objectives of these studies were to understand the effects of a delayed seeding date (0, 15, 30 and 45 d), seeding rate (15, 25, 35, 45, and 55 kg ha−1 of seed) and applied N fertilizer (20, 40, 60, 80, and 100 kg N ha−1) on the development and yield of annual canarygrass, to improve recommendations of best management practices in annual canarygrass and to determine the impact of these factors on yield variability in annual canarygrass. To address these objectives, three single factor field experiments were conducted, at a number of sites in Saskatchewan from 1998 to 2001. Seeding date had a large effect on grain yield. Grain yield decreased as seeding was delayed by 30 and 45 d from early May. Seeding rate had a small effect on grain yield. The response curve was very shallow peaking at approximately 1310 kg ha−1 at a seeding rate of 45 kg ha−1. Variation in grain yield tended to decrease as the seeding rate increased. There was a small increase in grain yield with the addition of nitrogen fertilizer. The response curve estimated a maximum yield of 1215 kg ha−1, which was obtained with a nitrogen rate of 78 kg ha−1. The majority of the increase was between 20 and 40 kg N ha−1, with a 2.3 kg ha−1 increase in grain yield for each kg of fertilizer N in that range of rates. There was a slight increase in grain yield as the nitrogen rate increased above 40 kg ha−1 but the variation in grain yield also increased reducing the incentive for growers to use N rates above 40 kg ha−1. Seeding date had a large effect on seed yield and could impact yield variability while seeding rate and nitrogen rate did not have a large effect on seed yield or yield variability.
Complexity and composition of pasture swards affect plant productivity and soil organisms
Authors: McElroy M. S. , Papadopoulos Y. A. , Adl M. S.
Published: June 2012

McElroy, M. S., Papadopoulos, Y. A. and Adl, M. S. 2012. Complexity and composition of pasture swards affect plant productivity and soil organisms. Can. J. Plant Sci. 92: 687–697. The relationships between ecosystem diversity, productivity, and stability is a central theme in current ecological research; the links between above-ground and below-ground ecosystems, as well as their effects on ecosystem services, are becoming more understood. While plant communities differ in primary productivity, and in the communities of soil organisms they support, it is unclear whether these differences are attributable mainly to plant community diversity or to the dominant plant species. This study evaluated the effect of these two factors on plant productivity, and abundance of soil microorganisms and functional diversity, in an establishing pasture using sward complexity (plant species present) and sward composition (identity of species) as treatments in a design using the step-wise addition of grass species. While sward complexity affected plant productivity, showing higher productivity in plots of higher diversity, abundance and functional diversity of soil organism groups were generally not consistently affected by sward complexity or composition. Sward composition did influence soil community composition; there was a close correlation between microbial catabolic activity and sward composition. This study shows that grassland plants have a limited effect on the size and diversity of soil communities while they are being established. This result may have consequences for soil ecosystem services.
Seeding depth and seeding speed effects on no-till canola emergence, maturity, yield and seed quality
Authors: Harker K. N. , O'Donovan J. T. , Blackshaw R. E. , Johnson E. N. , Lafond G. P. , May W. E.
Published: June 2012

Harker, K. N., O'Donovan, J. T., Blackshaw, R. E., Johnson, E. N., Lafond, G. P. and May, W. E. 2012. Seeding depth and seeding speed effects on no-till canola emergence, maturity, yield and seed quality. Can. J. Plant Sci. 92: 795–802. Canola seed costs are substantial, but only a relatively small proportion of planted seeds actually emerge as seedlings. Direct-seeded (no-till) experiments were conducted from 2008 to 2010 at four western Canada locations [Lacombe AB (2007–2010), Lethbridge AB, Indian Head SK, and Scott SK] to determine the influence of cultivar (hybrid vs. open-pollinated), seeding speed (6.4 vs. 11.2 k h−1), and seeding depth (1 vs. 4 cm) on the emergence, maturity, yield, and seed quality of glyphosate-resistant canola. Canola emergence density was positively associated with precipitation levels surrounding the time of seeding; other site and environmental predictors such as soil temperature, soil texture, soil organic matter, latitude and longitude did not consistently influence canola emergence density. The agronomic performance of hybrid canola, including seed yield and quality, was usually superior to open-pollinated canola, but there was no difference in emergence density between the two cultivars. However, the hybrid cultivar emerged 1 d earlier, grew faster and covered the ground more quickly than the open-pollinated cultivar; important results from a crop-weed competition standpoint. Although seeding depth did not influence average canola yield, it often had a major impact on canola emergence density. Under moist conditions, average canola emergence improved from 37 to 62% as seeding depth decreased from 4 to 1 cm, respectively. Seeding at a depth of 1 vs. 4 cm also decreased days to emergence, increased canola ground cover, decreased days to flowering and days to maturity and tended to decrease green seed levels. Relatively high canola emergence rates can reduce the need for additional herbicide applications, herbicide input costs and selection pressure for herbicide resistance. Relatively high canola stand densities can improve the ability of canola to successfully tolerate and accommodate biotic and abiotic stress.
Short Communication: Comparative soil water use by annual crops at a semiarid site in Montana
Authors: Miller P. R. , Holmes J. A.
Published: June 2012

Miller, P. R. and Holmes, J. A. 2012. Short Communication: Comparative soil water use by annual crops at a semiarid site in Montana. Can. J. Plant Sci. 92: 803–807. Results for soil water use in the semiarid northern Great Plains are presented in detailed tabular format for 15 crops in an ideal environment for comparative water use assessment. The effective rooting depth of winter wheat (Triticum aestivum L.) varied relative to spring wheat; it was often similar and never less. Sunflower (Helianthus annuus L.) averaged 43 mm greater soil water use below 0.9 m compared with spring wheat. Conversely, lentil (Lens culinaris Medik.) and pea (Pisum sativum L.) averaged 27 mm and 48 mm less soil water than spring wheat to a 1.2-m soil depth, respectively. Observed differences in effective rooting depth for alternative crops carry important implications for wheat-based cropping systems.
Review: Strategies to increase nitrogen use efficiency of spring barley
Authors: Anbessa Yadeta , Juskiw Patricia
Published: June 2012

Anbessa, Y. and Juskiw, P. 2012. Review: Strategies to increase nitrogen use efficiency of spring barley. Can. J. Plant Sci. 92: 617–625. Improvement in nitrogen use efficiency (NUE) is important to reduce input costs and the negative impact of excessive N on the environment. This review found that barley growers in western Canada have over the years adopted a number of improved N management strategies including soil testing and adjusting rate of N fertilization accordingly, switching from fall application to spring application of N fertilizers, and side-dressing placement of N that gives plant roots easier access to N nutrition. However, it is our opinion that use of variable N rates, choice of N fertilizer type that is less susceptible to losses, and improved manure management are some of the areas where further increase in NUE should be sought. As well, barley germplasms show substantial differences in NUE and genetic selection could increase NUE. Genetic improvement of NUE in barley should be possible both by the traditional breeding approach of crossing and pyramiding NUE genes from across different sources as well as through the development of transgenic barley. The integration of improved N management practices and more efficient cultivars may bring about a significant increase in NUE and ultimately grain yield of barley under the target moderate rate of N application.
Response of dry beans to halosulfuron applied postemergence
Authors: Soltani Nader , Shropshire Christy , Sikkema Peter H.
Published: June 2012

Soltani, N., Shropshire, C. and Sikkema, P. H. 2012. Response of dry beans to halosulfuron applied postemergence. Can. J. Plant Sci. 92: 723–728. Four field trials were conducted over a 2-yr period (2009 and 2010) at Exeter and Ridgetown, Ontario, to evaluate the tolerance of adzuki, black, cranberry, kidney, otebo, pinto, Small Red Mexican and white beans to halosulfuron applied postemergence (POST) at 35 and 70 g a.i. ha−1. All treatments including the non-treated control were maintained weed free during the growing season. Halosulfuron applied POST caused as much as 73, 7, 13, 12, 12, 11, 11 and 9% injury in adzuki, black, cranberry, kidney, otebo, pinto, Small Red Mexican (SRM) and white beans, respectively. Halosulfuron applied POST reduced adzuki bean height as much as 52 and 70% at Exeter and Ridgetown, respectively. Plant height was not affected in the other market classes of dry bean evaluated. Halosulfuron POST reduced shoot dry weight of adzuki bean 68% at both rates evaluated. Otebo and SRM bean shoot dry weight were not affected when halosulfuron was applied POST at 35 g a.i. ha−1 but otebo bean shoot dry weight was reduced 12% and SRM bean shoot dry weight was reduced 14% at 70 g a.i. ha−1. Shoot dry weight of black, cranberry, kidney, pinto and white bean was not affected with either rate of halosulfuron. Seed yield of adzuki bean was decreased 58% at 35 g a.i. ha−1 and 68% at 70 g a.i. ha−1 with halosulfuron. White bean yield was not affected with halosulfuron applied POST at 35 g a.i. ha−1 but was reduced 9% at 70 g a.i. ha−1. Seed yield of black, cranberry, kidney, otebo, pinto and SRM bean was not reduced with either rate of halosulfuron. Based on these results, there is not an adequate margin of crop safety for halosulfuron POST in adzuki bean. However, there is potential for POST application of halosulfuron in black, cranberry, kidney, otebo, pinto, SRM and white beans.
Stripe rust resistance among western Canadian spring wheat and triticale varieties
Authors: Randhawa H. , Puchalski B. J. , Frick M. , Goyal A. , Despins T. , Graf R. J. , Laroche A. , Gaudet D. A.
Published: June 2012

Randhawa, H., Puchalski, B. J., Frick, M., Goyal, A., Despins, T., Graf, R. J., Laroche, A. and Gaudet, D. A. 2012. Stripe rust resistance among western Canadian spring wheat and triticale varieties. Can. J. Plant Sci. 92: 713–722. Stripe rust (Puccinia striiformis Westend.) is an important pathogen of wheat in western Canada and worldwide. One hundred and four spring wheat and triticale varieties and cultivars were evaluated for resistance to stripe rust in nurseries at Lethbridge and Creston, BC, during 2009 and 2010. In the Canada Prairie Spring Red (CPSR) wheat class, newer varieties were more resistant compared with many of the older varieties. Among the white Canada Prairie Spring White (CPSW) wheats, Vista was moderately resistant, whereas Snowhite475 and Snowhite476 were susceptible. Little useful resistance was observed within the Canada Western Hard White Spring (CWHWS) class. Sixty percent of the Canada Western Red Spring (CWRS) wheats, including the currently popular varieties Lillian, Harvest and Kane, were resistant. Susceptible CWRS varieties that are extensively seeded in western Canada include AC Barrie, Superb and McKenzie, but also include the recently registered CDC Kernen and Vesper. The varieties were tested for the presence of the stripe rust genes Yr10, Yr17, Yr18 and Yr36 using molecular markers. Much of the stripe rust resistance, particularly in the CWRS, Canada Western Extra Strong (CWES), and CPSR wheat classes was attributed to the presence of adult plant resistance gene Yr18. Yr17 and Yr36 were also detected among CWRS and CWES varieties. However, the absence of markers for known genes in several resistant varieties indicated that uncharacterized genes for stripe rust occur among hexaploid wheats. Durum wheat and triticale varieties were universally resistant with the absence of tested markers. Therefore, there appear to be numerous sources of stripe rust resistance, both characterized and uncharacterized, among western Canadian spring wheat and triticale varieties.
Species dynamic, forage yield, and nutritive value of seeded native plant mixtures following grazing
Authors: Schellenberg M. P. , Biligetu B. , Iwaasa A. D.
Published: June 2012

Schellenberg, M. P, Biligetu, B. and Iwaasa, A. D. 2012. Species dynamic, forage yield, and nutritive value of seeded native plant mixtures following grazing. Can. J. Plant Sci. 92: 699–706. There is increasing interest in native plants of North America for rangeland reseeding in the semiarid regions of western Canada. However, there is limited information available on forage yield, nutritive value and response to grazing of seeded native plant mixture. The objective of this study was to compare foliar cover, forage yield, and nutritive value of two different native plant mixtures under grazing. In 2001–2004, a study was initiated on Orthic Brown Chernozemic (Aridic Haploboroll) soil near Swift Current (lat. 50°25'N, long. 107°44'W), Canada. The experimental design was a randomized complete block with a full factorial arrangement of seed mixtures (7 species and 14 species) and stocking rates (1.3 and 2.7 animal units ha−1) with four replications of each treatment combination. The 7-species mixture produced more forage than the 14-species mixture in July, August, and September of all study years. The 7-species mixture, however, had lower crude protein than the 14-species mixture in August and September in 2002 and 2003. Neutral detergent fiber and acid detergent fiber concentrations were generally similar between the two mixtures for July, August, and September sampling for all 3 yr. Foliar cover of awned wheatgrass [(Elymus trachycaulus (Link) Gould & Shin. ssp subsecundus (Link) A. & D. Love.] and slender wheatgrass [Elymus trachycaulus (Link) Gould subsp. trachycaulus] was higher in the 7-species mixture than the 14-species mixture, but foliar cover of other species was similar between the two mixtures. Shrub species were rarely observed in the stand at any year. Higher stocking rate decreased foliar cover of slender wheatgrass and weeds, but foliar cover of other species was similar between the two stocking rates. Based on the results, a seed mixture of native cool-season grasses may be more productive than a combination of native warm- and cool-season grasses under semiarid region of western Canada, but inclusion of warm-season grasses could improve nutritive value by increasing protein content in the late summer months.
Review: Microsite characteristics influencing weed seedling recruitment and implications for recruitment modeling
Authors: John Bullied W. , Van Acker Rene C. , Bullock Paul R.
Published: June 2012

Bullied, W. J., Van Acker, R. C. and Bullock, P. R. 2012. Review: Microsite characteristics influencing weed seedling recruitment and implications for recruitment modeling. Can. J. Plant Sci. 92: 627–650. A weed seedling recruitment microsite is the location of a weed seed in the soil profile which affects germination, time of emergence and seedling establishment. The relationship between the recruitment of seedlings and their physical environment, including microclimate, soil, topography, and residue cover can provide the key to understanding the timing of seedling recruitment. The variability that exists in germination and establishment requirements within and among weed species raises important questions for recruitment research addressing multiple species, as well as regional models of genetic variability within species. Current weed recruitment research focuses mainly on summer annual species in annual cropping systems. However, with changes in cropping systems, climate, and weed biology, there will be an increasing demand for the management of both summer and winter annual weeds that develop very early in the spring. Many studies to date take an average of microsite conditions, particularly for soil depth, to describe the seedling recruitment zone. Whereas this practice of under-sampling expedites lengthy and difficult soil environmental measurements, it limits the description of the microsite for predictive purposes. Because soil disturbance disperses seeds to microsites throughout the vertical profile of the shallow seedling recruitment zone, seeds are subjected to gradients of temperature and water that create diverse microsites with depth in the recruitment zone. Research on the interactions of microclimate, field topography, soil properties and agronomic practices can further our knowledge base of the seedling recruitment microsite to better understand weed ecology and population dynamics generally, as well as enhance our ability to predict seedling recruitment specifically.
The Biology of Canadian weeds. 150 Erechtites hieraciifolius (L.) Raf. ex DC.
Authors: Darbyshire Stephen J. , Francis Ardath , DiTommaso Antonio , Clements David R.
Published: June 2012

Darbyshire, S. J., Francis, A., DiTommaso, A. and Clements, D. R. 2012. The Biology of Canadian weeds. 150 Erechtites hieraciifolius (L.) Raf. ex DC. Can. J. Plant Sci. 92: 729–746. Erechtites hieraciifolius, American burnweed, is a herbaceous annual in the Asteraceae native to forest zones of eastern North America, but introduced to parts of Europe and the Pacific region. Confusion sometimes arises in distinguishing it from other weedy rayless composites in Canada, such as Senecio vulgaris (common groundsel) and Conyza canadensis (Canada fleabane). A pioneer therophyte species of forest zones, it occurs in large numbers when associated with major disturbances such as forest fires, but is also common in areas of smaller scale disturbance such as shores, forest edges and wind-throws. Soil conditions may vary greatly in nutrient content, moisture content, pH and salinity. In Canada, it is generally considered a minor garden and agricultural weed. It is most common in crops such as lowbush blueberry (Vaccinium spp.), cranberry (Vaccinium macrocarpon), strawberry (Fragaria×ananassa) and vegetable crops; however, it occasionally occurs in other field and forage crops. Impacts include a variety of problems contributing to increased production costs or crop yield losses, including herbicide resistance, resource competition, and as a reservoir harbouring crop pathogens. It has been valued as a medicinal herb for treating a variety of ailments. Populations may grow rapidly in response to disturbances typical of managed landscapes, but E. hieraciifolius can usually be effectively controlled by chemical, cultural or manual weed control tactics.
Localized Corrosion of Stainless Steel in a Nuclear Waste Cooling Water System—Part 2: Plant Inspection Findings
Authors: Donohoe C.J. , Whillock G.O.H. , Apps P.J.
Published: June 2012

Parts of a nuclear waste cooling water system, constructed from an austenitic stainless steel, are known to be susceptible to localized corrosion. This is attributed to the presence of chloride ions in the water, albeit only at low concentration (<10 mg/L), and oxidants produced by water radiolysis. Plate samples were cut and taken for examination from downstream tanks located in man-access areas out of the radiation field. Large pits were found. The largest were highly elongated but had failed to form through-wall penetrations. Smaller pits that were spheroidal in shape were found that had formed through-wall penetrations. The pits were sectioned and their internal morphologies examined by scanning electron microscopy. The elongated pits were found to have a crystalline internal morphology associated with the mechanism of etch-type pitting. The spheroidal pits had a smoother interior morphology but it was not bright or distinctive-like classic pits formed by a salt-filming mechanism. Formation of the spheroidal pits is attributed to corrosion by a quasi-salt-filming mechanism.
Current Efficiency in Accelerated Corrosion Testing of Concrete
Authors: Nossoni G. , Harichandran R.
Published: June 2012

The suitability of accelerated corrosion testing using an impressed current, especially the accuracy of Faraday's law to estimate the mass loss, was assessed in this paper. A variety of tests were performed in concrete and solution with different chloride concentrations and impressed current to assess the accuracy of using Faraday's law to estimate the mass loss of corroded steel. The results indicate that Faraday's law does not predict the mass loss accurately for all conditions, and the percentage error increases with decreasing chloride concentration in the system. It is hypothesized that Faraday's law cannot be used to estimate the mass loss because competing reactions take place at the anode, especially at low chloride concentrations and high current. Under unfavorable conditions, only a part of the impressed current oxidizes the anode to create corrosion products while the remaining current is consumed in competing reactions.
Service Life Projection for Chloride-Exposed Concrete Reinforced with Black and Corrosion-Resistant Bars
Authors: Hartt W.H.
Published: June 2012

Corrosion-induced deterioration of reinforced concrete is a pervasive problem internationally. In response to this, an equation has been derived whereby the fraction of electrochemically independent reinforced concrete elements within which corrosion-caused damage has resulted after a given exposure time is calculated. The approach considers that all relevant variables conform to some distribution rather than being discrete, as is now known to be the case. These variables are (1) surface Cl− concentration, (2) the effective Cl− diffusion coefficient, (3) concrete cover, and (4) the critical Cl− concentration threshold to initiate corrosion. Upon inputting (1) distribution parameters for the above variables, (2) the critical reinforcement corrosion loss to cause concrete damage, and (3) the average corrosion rate over the exposure period and numerically integrating, the fraction of elements that has experienced cracking/delamination after the selected time was determined. Upon repeating the calculation for incremental times, a cumulative distribution function plot for the occurrence of (1) corrosion initiation and (2) cracking/delamination was constructed. Example results are provided for concrete reinforced with both black bar and select corrosion-resistant reinforcements. The approach provides an improved tool for materials selection, service life projection, and maintenance planning.
Electrochemical Properties of Phosphate Coating on AZ31 Magnesium Alloy: Effect of Phosphating Process Parameters
Authors: Abbasi F. , Sarabi A.A.
Published: June 2012

In this work, the use of zinc phosphate coating to protect AZ31 magnesium alloy against corrosion is discussed. In addition, the effect of solution temperature and immersion time as two important process parameters during phosphating on the surface properties and corrosion resistance was studied. The morphology and composition of phosphate films formed on Mg alloy was investigated by using scanning electron microscopy (SEM) and x-ray diffraction (XRD). The results show that the phosphate coatings mainly contain hopeite (Zn3[PO4]2·4H2O) and have flower- and slab-like crystals at lower and higher solution temperatures, respectively. Meantime, electrochemical impedance spectroscopy (EIS) and direct current (DC) polarization were used to assess the corrosion protection property. The EIS results indicate that the phosphate film formed at 60°C during 5 min immersion can greatly improve the corrosion resistance of the AZ31 magnesium alloy.
Corrosion Investigations on Metal Waste Form Alloys of Titanium-Modified Type 316 Stainless Steel-Zirconium in Simulated Groundwater Media
Authors: Bairi L.R. , Ningshen S. , Mudali U. Kamachi , Raj B.
Published: June 2012

Corrosion assessment of metal waste form (MWF) alloys was carried out in two possible geological repository environments, simulated Kalpakkam groundwater (KGW) and Rajasthan groundwater (RGW). The corrosion resistance properties, passive film stability, and surface morphologies were evaluated by electrochemical and microscopic techniques. Studies were done in two main parts. First, different MWF alloys with varying Zr content from 5 wt% to 17 wt% were compared in KGW to evaluate better corrosion-resistant alloys. All the alloys exhibited a wide range of passivation potential, indicating passive film stability and fairly higher breakdown potentials. However, the alloy with 8.5 wt% Zr showed optimum open-circuit potential (OCP), nobler breakdown potential, optimum passive current, highest polarization resistance, and lowest capacitance; therefore, it was selected as the better alloy. In the second part of the study, the corrosion properties of this better alloy were compared in two simulated RGW media and KGW media. Results showed that because of the lower concentration of chloride in RGW media, the passive film stability was excellent. Scanning electron microscopic observation of surface morphologies after electrochemical studies in both groundwater media showed insignificant corrosion attack. Therefore, this study has clearly shown excellent corrosion performance and good applicability of MWF alloys for geological disposal.
Influence of Microstructure on Pitting Corrosion Resistance of Alloy 904L Superaustenitic Stainless Steel
Authors: Barbosa B.A.R.S. , Tavares S.S.M. , Cobuci A. , de Macêdo M.C.S.
Published: June 2012

Alloy 904L (UNS N08904) is a superaustenitc stainless steel with high Cr and Mo additions. The steel also contains high nickel content, which is important to maintain the austenitic structure. Because of its high corrosion resistance, Type 904L alloy is being used in much equipment in chemical and petrochemical plants. Some of this equipment may experience high temperatures in service or during fabrication. The microstructural changes associated with exposures in the range of 650°C to 850°C or as a consequence of melting were analyzed in this paper. The microstructure/corrosion resistance relationships were studied by means of electrochemical pitting corrosion tests and microstructural analysis. Critical pitting temperatures (CPT) of annealed and cast specimens were determined and compared. The results show that the corrosion resistance can vary significantly with fabrication processes and/or service at high temperatures.
Scanning Kelvin Probe Investigation of Corrosion Under Thick Marine Paint Systems Applied on Carbon Steel
Authors: Nazarov A. , Le Bozec N. , Thierry D. , Le Calvé P. , Pautasso J.-P.
Published: June 2012

The scanning Kelvin probe (SKP) is a non-destructive technique for measuring the surface distribution of the Volta potential with a high spatial resolution of a few tens of micrometers. The SKP technique allows in situ studies of the localized corrosion processes under atmospheric weathering conditions, on metal surfaces, or underneath organic coatings. In the present study, the SKP technique was used to follow the kinetics of underpaint corrosion from a defect applied on steel coated with thick marine paint systems (0.4 mm to 0.5 mm) as a function of exposure time in an accelerated corrosion test. Three different paint systems were investigated. In addition, the influence of surface cleanliness in terms of salt concentration on a steel substrate prior to paint application was investigated using the SKP technique. The results showed the high efficiency of the SKP technique for early corrosion evaluation under thick paints on steel substrate.
Evolution of Competition in Vietnam Industries over the Recent Economic Transition
Authors: Doan Tinh , Stevens Philip
Published: June 2012

Vietnam has gone through massive economic restructuring from a socialist command economy to market-oriented economy. This provides an excellent example of a country that has experienced changes in competition regime. Economic reforms in late 1980s and 1990s and the introduction of pro-competitive policies in the first half of 2000s have radically altered the economic and, in particular, competitive environment. Understanding the evolution of competition across industries is an important step towards understanding the impact of economic reform on the economic performance of Vietnam as a result of the economic transition. In this paper, the authors investigate the evolution of competition in Vietnam during the economic transition using the price-cost margin (or Lerner Index) and the profit elasticity measure recently developed by Boone (Competition, 2000). This paper provides the first empirical study of intensity and evolution of competition across majority of industries in Vietnam in the last decade using firm-level data from the Vietnam Enterprise Census (VEC) conducted annually since 2000 by the Vietnam General Statistical Office (GSO).
Persistence of ozone anomalies in the Arctic stratospheric vortex in autumn
Authors: Blessmann D. , Wohltmann I. , Lehmann R. , Rex M.
Published: June 2012

Abstract. Dynamical processes during the formation phase of the Arctic stratospheric vortex in autumn (from September to December) can introduce considerable interannual variability in the amount of ozone that is incorporated into the vortex. Chemistry in autumn tends to remove part of this variability because ozone relaxes towards equilibrium. As a quantitative measure of how important dynamical variability during vortex formation is for the winter ozone abundances above the Arctic we analyze which fraction of an ozone anomaly induced during vortex formation persists until early winter (3 January). The work is based on the Lagrangian Chemistry Transport Model ATLAS. In a case study, model runs for the winter 1999–2000 are used to assess the fate of an ozone anomaly artificially introduced during the vortex formation phase on 16 September. In addition, runs with reduced resolution explore the sensitivity of the results to interannual changes in transport, mixing, temperatures and NOx. The runs provide information about the persistence of the induced ozone anomaly as a function of time, potential temperature and latitude. The induced ozone anomaly survives longer inside the polar vortex than outside the vortex. Half of the initial perturbation survives until 3 January at 550 K inside the polar vortex, with a rapid fall off towards higher levels, mainly due to NOx induced chemistry. Above 750 K the signal falls to values below 0.5%. Hence, dynamically induced ozone variability from the early vortex formation phase cannot significantly contribute to early winter variability above 750 K. At lower levels increasingly larger fractions of the initial perturbation survive, reaching 90% at 450 K. In this vertical range dynamical processes during the vortex formation phase are crucial for the ozone abundance in early winter.
Effect of chemical degradation on fluxes of reactive compounds – a study with a stochastic Lagrangian transport model
Authors: Rinne J. , Markkanen T. , Ruuskanen T. M. , Petäjä T. , Keronen P. , Tang M.J. , Crowley J. N. , Rannik Ü. , Vesala T.
Published: June 2012

Abstract. In the analyses of VOC fluxes measured above plant canopies, one usually assumes the flux above canopy to equal the exchange at the surface. Thus one assumes the chemical degradation to be much slower than the turbulent transport. We used a stochastic Lagrangian transport model in which the chemical degradation was described as first order decay in order to study the effect of the chemical degradation on above canopy fluxes of chemically reactive species. With the model we explored the sensitivity of the ratio of the above canopy flux to the surface emission on several parameters such as chemical lifetime of the compound, friction velocity, stability, and canopy density. Our results show that friction velocity and chemical lifetime affected the loss during transport the most. The canopy density had a significant effect if the chemically reactive compound was emitted from the forest floor. We used the results of the simulations together with oxidant data measured during HUMPPA-COPEC-2010 campaign at a Scots pine site to estimate the effect of the chemistry on fluxes of three typical biogenic VOCs, isoprene, α-pinene, and β-caryophyllene. Of these, the chemical degradation had a major effect on the fluxes of the most reactive species β-caryophyllene, while the fluxes of α-pinene were affected during nighttime. For these two compounds representing the mono- and sesquiterpenes groups, the effect of chemical degradation had also a significant diurnal cycle with the highest chemical loss at night. The different day and night time loss terms need to be accounted for, when measured fluxes of reactive compounds are used to reveal relations between primary emission and environmental parameters.
Influence of aerosol and surface reflectance variability on hyperspectral observed radiance
Authors: Bassani C. , Cavalli R. M. , Antonelli P.
Published: June 2012

Abstract. Current aerosol retrievals based on visible and near infrared remote-sensing, are prone to loss of accuracy, where the assumptions of the applied algorithm are violated. This happens mostly over land and it is related to misrepresentation of specific aerosol conditions or surface properties. New satellite missions, based on high spectral resolution instruments, such as PRISMA (Hyperspectral Precursor of the Application Mission), represent a valuable opportunity to improve the accuracy of τa550 retrievable from a remote-sensing system developing new atmospheric measurement techniques. This paper aims to address the potential of these new observing systems in more accurate retrieving τa550, specifically over land in heterogeneous and/or homogeneous areas composed by dark and bright targets. The study shows how the variation of the hyperspectral observed radiance can be addressed to recognise a variation of Δτa550 = 0.02. The goal has been achieved by using simulated radiances by combining two aerosol models (urban and continental) and two reflecting surfaces: dark (represented by water) and bright (represented by sand) for the PRISMA instrument, considering the environmental contribution of the observed radiance, i.e., the adjacency effect. Results showed that, in the continental regime, the expected instrument sensitivity would allow for retrieval accuracy of the aerosol optical thickness at 550 nm of 0.02 or better, with a dark surface surrounded by dark areas. The study also showed that for the urban regime, the surface plays a more significant role, with a bright surface surrounded by dark areas providing favourable conditions for the aerosol load retrievals, and dark surfaces representing less suitable situations for inversion independently of the surroundings. However, over all, the results obtained provide evidence that high resolution observations of Earth spectrum between 400 and 1000 nm would allow for a significant improvement of the accuracy of the τa550 for anthropogenic/natural aerosols over land.
Sensitivity of the North Atlantic climate to Greenland Ice Sheet melting during the Last Interglacial
Authors: Bakker P. , Van Meerbeeck C. J. , Renssen H.
Published: June 2012

Abstract. During the Last Interglacial (LIG; ~130 000 yr BP), part of the Greenland Ice Sheet (GIS) melted due to a warmer than present-day climate. However, the impact of this melting on the LIG climate in the North Atlantic region is relatively unknown. Using the LOVECLIM Earth system model of intermediate complexity, we have systematically tested the sensitivity of the LIG climate to increased freshwater runoff from the GIS. In addition, experiments have been performed to investigate the impact of an idealized reduction of both surface elevation and extent of the GIS on the LIG climate. Based on changes in the maximum sea-ice cover and the strength of the overturning circulation, three regimes have been identified, which are characterized by a specific pattern of surface temperature change in the North Atlantic region. By comparing the simulated deep ocean circulation with proxy-based reconstructions, the most realistic simulated climate could be discerned. The resulting climate is characterized by a shutdown of deep convection and a subsequent ~4 °C cooling in the Labrador Sea. Furthermore, a cooling of ~1 °C over the North Atlantic Ocean between 40° N and 70° N is seen. The prescribed reduction in surface elevation and extent of the GIS results in a local warming of up to 4 °C and amplifies the freshwater-forced reduction in deep convection and the resultant cooling in the Nordic Seas. A further comparison of simulated summer temperatures with both continental and oceanic proxy records reveals that the partial melting of the GIS during the LIG could have delayed maximum summer temperatures in the western part of the North Atlantic region relative to the insolation maximum.
Modern sedimentation patterns in Lake El'gygytgyn, NE Russia, derived from surface sediment and inlet streams samples
Authors: Wennrich V. , Francke A. , Dehnert A. , Juschus O. , Leipe T. , Vogt C. , Brigham-Grette J. , Minyuk P. S. , Melles M. ,   El'gygytgyn Science Party
Published: June 2012

Abstract. High Arctic Lake El'gygytgyn/NE Russia holds a continuous 3.58 Ma sediment record, which is regarded as the most long-lasting climate archive of the terrestrial Arctic. Based on multi-proxy geochemical, mineralogical and granulometric analyses of surface sediment, inlet stream and bedrock samples, supplemented by statistical methods, major processes influencing the modern sedimentation in the lake were investigated. Grain-size parameters and chemical elements linked to the input of feldspars from acidic bedrock indicate a wind-induced two-cell current system as major driver of sediment transport and accumulation processes in Lake El'gygytgyn. The distribution of mafic-rock related elements in the sediment on the lake floor can be traced back to the input of weathering products of basaltic rocks in the catchment. Obvious similarities in the spatial variability of manganese and heavy metals indicate sorption or co-precipitaion of these elements with Fe and Mn hydroxides and oxides. But the akin distribution of organic matter content might also point to a fixation to organic components. An enrichment of mercury in the inlet streams might be indicative of neotectonic activity around the lake. The results of this study add to the fundamental knowledge of the in-lake processes of Lake El'gygytgyn and its lake-catchment interactions, and thus, yield crucial insights for the interpretation of paleo-data from this unique archive.
Influence of ecohydrologic feedbacks from simulated crop growth on integrated regional hydrologic simulations under climate scenarios
Authors: van Walsum P. E. V. , Supit I.
Published: June 2012

Abstract. Hydrologic climate change modelling is hampered by climate-dependent model parameterizations. To reduce this dependency, we extended the regional hydrologic modelling framework SIMGRO to host a two-way coupling between the soil moisture model MetaSWAP and the crop growth simulation model WOFOST, accounting for ecohydrologic feedbacks in terms of radiation fraction that reaches the soil, crop coefficient, interception fraction of rainfall, interception storage capacity, and root zone depth. Except for the last, these feedbacks are dependent on the leaf area index (LAI). The influence of regional groundwater on crop growth is included via a coupling to MODFLOW. Two versions of the MetaSWAP-WOFOST coupling were set up: one with exogenous vegetation parameters, the "static" model, and one with endogenous crop growth simulation, the "dynamic" model. Parameterization of the static and dynamic models ensured that for the current climate the simulated long-term averages of actual evapotranspiration are the same for both models. Simulations were made for two climate scenarios and two crops: grass and potato. In the dynamic model, higher temperatures in a warm year under the current climate resulted in accelerated crop development, and in the case of potato a shorter growing season, thus partly avoiding the late summer heat. The static model has a higher potential transpiration; depending on the available soil moisture, this translates to a higher actual transpiration. This difference between static and dynamic models is enlarged by climate change in combination with higher CO2 concentrations. Including the dynamic crop simulation gives for potato (and other annual arable land crops) systematically higher effects on the predicted recharge change due to climate change. Crop yields from soils with poor water retention capacities strongly depend on capillary rise if moisture supply from other sources is limited. Thus, including a crop simulation model in an integrated hydrologic simulation provides a valuable addition for hydrologic modelling as well as for crop modelling.
Long-range hydrometeorological ensemble predictions of drought parameters
Authors: Fundel F. , Jörg-Hess S. , Zappa M.
Published: June 2012

Abstract. Low streamflow as consequence of a drought event affects numerous aspects of life. Economic sectors that may be impacted by drought are, e.g. power production, agriculture, tourism and water quality management. Numerical models have increasingly been used to forecast low-flow and have become the focus of recent research. Here, we consider daily ensemble runoff forecasts for the river Thur, which has its source in the Swiss Alps. We focus on the low-flow indices duration, severity and magnitude, with a forecast lead-time of one month, to assess their potential usefulness for predictions. The ECMWF VarEPS 5 member reforecast, which covers 18 yr, is used as forcing for the hydrological model PREVAH. A thorough verification shows that, compared to peak flow, probabilistic low-flow forecasts are skillful for longer lead-times, low-flow index forecasts could also be beneficially included in a decision-making process. The results suggest monthly runoff forecasts are useful for accessing the risk of hydrological droughts.