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1

Aerosol influenza transmission risk contours: A study of humid tropics versus winter temperate zone  

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Full Text Available Abstract Background In recent years, much attention has been given to the spread of influenza around the world. With the continuing human outbreak of H5N1 beginning in 2003 and the H1N1 pandemic in 2009, focus on influenza and other respiratory viruses has been increased. It has been accepted for decades that international travel via jet aircraft is a major vector for global spread of influenza, and epidemiological differences between tropical and temperate regions observed. Thus we wanted to study how indoor environmental conditions (enclosed locations in the tropics and winter temperate zones contribute to the aerosol spread of influenza by travelers. To this end, a survey consisting of 632 readings of temperature (T versus relative humidity (RH in 389 different enclosed locations air travelers are likely to visit in 8 tropical nations were compared to 102 such readings in 2 Australian cities, including ground transport, hotels, shops, offices and other publicly accessible locations, along with 586 time course readings from aircraft. Results An influenza transmission risk contour map was developed for T versus RH. Empirical equations were created for estimating: 1. risk relative to temperature and RH, and 2. time parameterized influenza transmission risk. Using the transmission risk contours and equations, transmission risk for each country's locations was compared with influenza reports from the countries. Higher risk enclosed locations in the tropics included new automobile transport, luxury buses, luxury hotels, and bank branches. Most temperate locations were high risk. Conclusion Environmental control is recommended for public health mitigation focused on higher risk enclosed locations. Public health can make use of the methods developed to track potential vulnerability to aerosol influenza. The methods presented can also be used in influenza modeling. Accounting for differential aerosol transmission using T and RH can potentially explain anomalies of influenza epidemiology in addition to seasonality in temperate climates.

Borup Birthe

2010-05-01

2

Long range transport of caesium isotopes from temperate latitudes to the equatorial zone during the winter monsoon period  

International Nuclear Information System (INIS)

An air radioactivity monitoring study carried out at Dalat, Viet Nam, since 1986 has revealed distinct peaks of caesium isotope concentrations in air and fallout during the period of December and January when the monthly average air temperature was lowest and dry fallout dominated. These peaks provide evidence of the intrusion of more radioactive cold air masses from temperate northern latitudes during the development of large scale anticyclones, frequently observed in the most active winter monsoon period. The high dry fallout velocity (about 10 cm/s), determined from the measured concentrations, clearly demonstrates one of the most relevant features of cold air masses: behind the cold front, vertical air motion is descending. The role of other processes such as injection of radioactive air from the stratosphere and local resuspension of soil dust has been shown to be insignificant. The interpretation of the experimental results was based on the analysis of environmental-meteorological factors as well as the behaviour of other naturally occurring radionuclides. (author). 7 refs, 2 figs

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Recurrent winter warming pulses enhance nitrogen cycling and soil biotic activity in temperate heathland and grassland mesocosms  

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Full Text Available Winter air temperatures are projected to increase in the temperate zone, whereas snow cover is projected to decrease, leading to more extreme soil temperature variability, and potentially to changes in nutrient cycling. Therefore, we applied six winter warming pulses by infra-red heating lamps and surface heating wires in a field experiment over one winter in temperate heathland and grassland mesocosms. The experiment was replicated at two sites, a colder mountainous upland site with high snow accumulation and a warmer and dryer lowland site. Winter warming pulses enhanced soil biotic activity for both sites during winter, as indicated by 35% higher nitrogen (N availability in the soil solution, 40% higher belowground decomposition and a 25% increase in the activity of the enzyme cellobiohydrolase. The mobilization of N differed between sites, and the incorporation of 15N into leaves was reduced by 31% in response to winter warming pulses, but only at the cold site, with significant reductions occurring for three of four tested plant species at this site. Furthermore, there was a trend of increased N leaching in response to the recurrent winter warming pulses. Overall, projected winter climate change in the temperate zone, with less snow and more variable soil temperatures, appears important for shifts in ecosystem functioning (i.e. nutrient cycling. While the effects of warming pulses on plant N mobilization did not differ among sites, reduced plant 15N incorporation at the colder temperate site suggests that frost damage may reduce plant performance in a warmer world, with important implications for nitrogen cycling and nitrogen losses from ecosystems.

J. Schuerings

2014-06-01

4

Plasmodium vivax malaria : a re-emerging threat for temperate climate zones?  

DEFF Research Database (Denmark)

Plasmodium vivax was endemic in temperate areas in historic times up to the middle of last century. Temperate climate P. vivax has a long incubation time of up to 8-10 months, which partly explain how it can be endemic in temperate areas with a could winter. P. vivax disappeared from Europe within the last 40-60 years, and this change was not related to climatic changes. The surge of P. vivax in Northern Europe after the second world war was related to displacement of refugees and large movement of military personnel exposed to malaria. Lately P. vivax has been seen along the demilitarized zone in South Korea replication a high endemicity in North Korea. The potential of transmission of P. vivax still exist in temperate zones, but reintroduction in a larger scale of P. vivax to areas without present transmission require large population movements of P. vivax infected people. The highest threat at present is refugees from P. vivax endemic North Korea entering China and South Korea in large numbers.

Petersen, Eskild; Severini, Carlo

2013-01-01

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Forecasting temperate alpine glacier survival from accumulation zone observations  

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Full Text Available Temperate alpine glacier survival is dependent on the consistent presence of an accumulation zone. Frequent low accumulation area ratio values, below 30%, indicate the lack of a consistent accumulation zone, which leads to substantial thinning of the glacier in the accumulation zone. This thinning is often evident from substantial marginal recession, emergence of new rock outcrops and surface elevation decline in the accumulation zone. In the North Cascades 9 of the 12 examined glaciers exhibit characteristics of substantial accumulation zone thinning; marginal recession or emergent bedrock areas in the accumulation zone. The longitudinal profile thinning factor, f, which is a measure of the ratio of thinning in the accumulation zone to that at the terminus, is above 0.6 for all glaciers exhibiting accumulation zone thinning characteristics. The ratio of accumulation zone thinning to cumulative mass balance is above 0.5 for glacier experiencing substantial accumulation zone thinning. Without a consistent accumulation zone these glaciers are forecast not to survive the current climate or future additional warming. The results vary considerably with adjacent glaciers having a different survival forecast. This emphasizes the danger of extrapolating survival from one glacier to the next.

M. S. Pelto

2010-01-01

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Controls on winter ecosystem respiration in temperate and boreal ecosystems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal patterns of winter ecosystem respiration (Reco) of northern ecosystems are poorly under...

2011-01-01

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Indoor air quality in typical temperate zone Australian dwellings  

Science.gov (United States)

We report the results of a comprehensive study of indoor air quality in typical temperate zone Australian dwellings. Forty dwellings located over an 800 km2 area in the south-east of Melbourne with a range of ages, materials and structures representative of Australian dwellings were selected. A range of indoor air quality pollutants were sampled both inside and outside for one week each in Winter/Spring 2008 and Summer/Autumn 2009. Information was collected on house characteristics, the surrounding areas and occupant activities during the sampling. Weekly indoor averaged CO2 (536 ± 121 ppm), CO (0.3 ± 0.2 ppm), PM2.5 (8.4 ± 4.0 ?g m-3), temperatures (21.2 ± 2.0 °C), water vapour mixing ratios (7.9 ± 1.3 g kg-1), benzene (1.3 ± 1.1 ?g m-3), toluene (8.8 ± 7.9 ?g m-3) and xylenes (6.2 ± 6.7 ?g m-3) varied from 1.1 to approximately three times higher compared to the equivalent outdoors concentrations. Formaldehyde (12.2 ± 4.7 ppb), other carbonyls (7.9 ± 2.6 ppb) and total volatile organic compounds (181.1 ± 89.5 ?g m-3) had indoor concentrations of factors between eight and 12 times higher compared to outdoor concentrations. Weekly averaged indoor ozone (0.7 ± 0.7 ppb), NO2 (8.4 ± 3.9 ppb) and PM10 (20.4 ± 8.1 ?g m-3) were significantly lower than outdoors. Correlations and factor analysis showed the major influences on this indoor air quality were (a) dwelling age, whereby dwellings constructed in recent decades compared to older buildings were found to have increased concentrations of the highly elevated species formaldehyde, other carbonyls and total volatile organic compounds, and (b) combustion and cooking activities that increased the concentrations of multiple species including CO, CO2, NO2, H2O and particles. The indoor pollutant concentrations from this study were in general comparable with or lower than other Australian or overseas studies.

Molloy, S. B.; Cheng, M.; Galbally, I. E.; Keywood, M. D.; Lawson, S. J.; Powell, J. C.; Gillett, R.; Dunne, E.; Selleck, P. W.

2012-07-01

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Forecasting temperate alpine glacier survival from accumulation zone observations  

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Full Text Available For temperate alpine glaciers survival is dependent on the consistent presence of an accumulation zone. The lack of a consistent and persistent accumulation zone leads to substantial thinning of the glacier in the accumulation zone. Accumulation zone thinning is evident in satellite imagery or field observation based the emergence of new rock outcrops or the recession of the margin of the glacier in the accumulation zone along a substantial portion of its perimeter. In either case the accumulation zone is no longer functioning as an accumulation zone and survival is unlikely. In both the North Cascades and Wind River Range nine of the fifteen glaciers examined are forecast not to survive the current climate or future additional warming. The results vary considerably with adjacent glaciers having a different survival forecast. This emphasizes the danger of extrapolating survival from one glacier to the next. This trait also emphasizes the value of a simple forecasting tool that can be applied to all glaciers. The automated remote sensing based glacier classification schemes developed offer the potential for automating this process based on the changes in the glacier outline.

M. S. Pelto

2009-05-01

9

Controls on winter ecosystem respiration in temperate and boreal ecosystems  

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Full Text Available Winter CO2 fluxes represent an important component of the annual carbon budget in northern ecosystems. Understanding winter respiration processes and their responses to climate change is also central to our ability to assess terrestrial carbon cycle and climate feedbacks in the future. However, the factors influencing the spatial and temporal patterns of winter ecosystem respiration (Reco of northern ecosystems are poorly understood. For this reason, we analyzed eddy covariance flux data from 57 ecosystem sites ranging from ~35° N to ~70° N. Deciduous forests were characterized by the highest winter Reco rates (0.90 ± 0.39 g C m?2 d?1, when winter is defined as the period during which daily air temperature remains below 0 °C. By contrast, arctic wetlands had the lowest winter Reco rates (0.02 ± 0.02 g C m?2 d?1. Mixed forests, evergreen needle-leaved forests, grasslands, croplands and boreal wetlands were characterized by intermediate winter Reco rates (g C m?2 d?1 of 0.70(±0.33, 0.60(±0.38, 0.62(±0.43, 0.49(±0.22 and 0.27(±0.08, respectively. Our cross site analysis showed that winter air (Tair and soil (Tsoil temperature played a dominating role in determining the spatial patterns of winter Reco in both forest and managed ecosystems (grasslands and croplands. Besides temperature, the seasonal amplitude of the leaf area index (LAI, inferred from satellite observation, or growing season gross primary productivity, which we use here as a proxy for the amount of recent carbon available for Reco in the subsequent winter, played a marginal role in winter CO2 emissions from forest ecosystems. We found that winter Reco sensitivity to temperature variation across space (QS was higher than the one over time (interannual, QT. This can be expected because QS not only accounts for climate gradients across sites but also for (positively correlated the spatial variability of substrate quantity. Thus, if the models estimate future warming impacts on Reco based on QS rather than QT, this could overestimate the impact of temperature changes.

T. Wang

2011-07-01

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Dams release methane even in temperate zoned; Les barrages emettent aussi du methane en zones temperees  

Energy Technology Data Exchange (ETDEWEB)

The Wohlen lake (near Bern) is a retaining dam built 90 years ago that has undergone a campaign to measure the quantity of methane released. The campaign lasted 1 year and the result was unexpected: 0.15 g/m{sup 2}*day which one of the highest release rates in temperate zones. This result is all the more stunning since water stays only 2 days in average in the reservoir and that the drowned area is not important. In fact the river Aar that feeds the lake is loaded with organic matter coming from humane activities: agriculture and 3 sewage plants. This organic matter decays in the lake releasing methane. (A.C.)

Lemarchand, F.

2010-12-15

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Establishing the breeding provenance of a temperate-wintering North American passerine, the Golden-crowned Sparrow, using light-level geolocation.  

Science.gov (United States)

The migratory biology and connectivity of passerines remains poorly known, even for those that move primarily within the temperate zone. We used light-level geolocators to describe the migratory geography of a North American temperate migrant passerine. From February to March of 2010, we attached geolocator tags to 33 Golden-crowned Sparrows (Zonotrichia atricapilla) wintering on the central coast of California, USA, and recovered four tags the following winter (October to December 2010). We used a bayesian state-space model to estimate the most likely breeding locations. All four birds spent the breeding season on the coast of the Gulf of Alaska. These locations spanned approximately 1200 kilometers, and none of the individuals bred in the same location. Speed of migration was nearly twice as fast during spring than fall. The return rate of birds tagged the previous season (33%) was similar to that of control birds (39%), but comparing return rates was complicated because 7 of 11 returning birds had lost their tags. For birds that we recaptured before spring migration, we found no significant difference in mass change between tagged and control birds. Our results provide insight into the previously-unknown breeding provenance of a wintering population of Golden-crowned Sparrows and provide more evidence of the contributions that light-level geolocation can make to our understanding of the migratory geography of small passerines. PMID:22506055

Seavy, Nathaniel E; Humple, Diana L; Cormier, Renée L; Gardali, Thomas

2012-01-01

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Winter photosynthetic activity of twenty temperate semi-desert sand grassland species.  

Science.gov (United States)

The winter photosynthetic activity (quantified by net CO(2) assimilation rates and chlorophyll (Chl) a fluorescence parameters) of 20 plant species (including two lichens and two mosses) of a Hungarian temperate semi-desert sand grassland was determined on one occasion per year in 1984, 1989 and 1994. Throughout winter, the overwintering green shoots, leaves or thalli were regularly exposed to below zero temperatures at night and daytime temperatures of 0-5 degrees C. In situ tissue temperature varied between -2.1 and +6.9 degrees C and the photosynthetic photon flux density (PPFD) between 137 and 351 micromol m(-2)s(-1). Under these conditions 18 of the grassland species exhibited photosynthetic CO(2) uptake (range: vascular plants ca. 0.2-3.8 micromol m(-2)s(-1), cryptogams 0.3-2.79 micromol kg(-1)s(-1)) and values of 0.9-5.1 of the Chl fluorescence decrease ratio R(Fd). In 1984, Festuca vaginata and Sedum sexangulare had net CO(2) assimilation at leaf temperatures of -0.85 to -1.2 degrees C. In 1989, all species except Cladonia furcata showed net CO(2) assimilation at tissue temperatures of 0 to +3.3 degrees C, with the highest rates observed in Poa bulbosa and F. vaginata. The latter showed a net CO(2) assimilation saturation at a PPFD of 600 micromol m(-2)s(-1) and a temperature optimum between +5 and +18 degrees C. At the 1994 measurements, the photosynthetic rates were higher at higher tissue water contents. The two mosses and lichens had a net photosynthesis (range: 1.1-2.79 micromol CO(2)kg(-1)s(-1)) at 2 degrees C tissue temperature and at 4-5 degrees C air temperature. Ca. 80% of the vascular grassland plant species maintained a positive C-balance during the coldest periods of winter, with photosynthetic rates of 1.5-3.8 micromol CO(2)m(-2)s(-1). In an extremely warm beginning March of the relatively warm winter of 2006/2007, the dicotyledonous plants had much higher CO(2) assimilation rates on a Chl (range 6-14.9 micromol g(-1)Chl s(-1)) and on a dry weight basis (9-48 micromol kg(-1)dw s(-1)) than in the cold winter of 1994. However, the assimilation rates of the three investigated cryptogams (Tortula and two Cladonia) and the two grasses Festuca and Poa were not affected by this increase. The results indicate that the photosynthetic activity of temperate semi-desert sand grassland species can help somewhat in slowing the general CO(2) rise in winter and function as a potential carbon sink of the investigated semi-desert Hungarian grassland species. PMID:18346813

Tuba, Zoltán; Csintalan, Zsolt; Szente, Kálmán; Nagy, Zoltán; Fekete, Gábor; Larcher, Walter; Lichtenthaler, Hartmut K

2008-09-29

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Salinity-linked growth in anguillid eels and the paradox of temperate-zone catadromy.  

Science.gov (United States)

Temperate-zone anguillid eels use both saline (marine or brackish) and fresh waters during their continental phase, but use of fresh waters is paradoxical because on average these fishes grow more rapidly in saline than in fresh waters. Based on data from anguillid eels whose habitat-residency histories had been determined by Sr:Ca otolithometry, superiority of growth rates in saline water is much greater in American eels Anguilla rostrata in north-eastern North America (mean saline:fresh growth rate ratio 2.07) than in European Anguilla anguilla, Japanese Anguilla japonica and shortfinned Anguilla australis eels (range of mean ratios 1.12-1.14). Data from A. rostrata in the Hudson Estuary, U.S.A., and Prince Edward Island, Canada, were used to test adaptive explanations of catadromous migrations. The hypothesis that lower mortality in fresh water offsets faster growth in saline water was not supported because loss (mortality + emigration ) rates did not vary between saline and fresh zones of the Hudson Estuary. Hypotheses that anguillid eels move to fresh water to escape from larger anguillid eels in saline water or to evaluate habitat quality were not supported by size and age distributions. Catadromy in temperate-zone anguillid eels increases the diversity of occupied habitats and therefore lowers fitness variance caused by environmental fluctuations. Catadromy in temperate-zone anguillid eels could be due to natural selection for maximum geometric mean fitness which is sensitive to fitness variance. Temperate-zone catadromy might also be maladaptive, at least in local areas, due to shifts over time in selective pressures or to inability of panmictic genetic systems to adapt to local conditions. PMID:20735690

Cairns, D K; Secor, D A; Morrison, W E; Hallett, J A

2009-06-01

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Dynamics of low-temperature acclimation in temperate and boreal conifer foliage in a mild winter climate.  

Science.gov (United States)

To provide baseline data for physiological studies of extreme low-temperature (LT) tolerance in boreal conifers, we profiled LT stress responses, liquid nitrogen (LN(2))-quench tolerance, and sugar concentrations in foliage of boreal-temperate species pairs in the genera Abies, Picea and Pinus, growing in an arboretum in a temperate oceanic climate from August 2006 through April 2007. The boreal species acclimated more rapidly and deeply than the temperate species, acquiring LN(2)-quench tolerance by late November, despite unusually warm conditions throughout the autumn and early winter. Maximum LT tolerance in the temperate species was in the -25 to -35 degrees C range, and was reached only after a period of freezing temperatures in late January and February. During LT acclimation in the temperate species, sigmoid temperature-relative electrolyte leakage (REL) curves shifted toward lower temperatures, whereas in boreal species there was both a temperature shift and a lowering of the maximum REL until it fell below a threshold associated with irreversible injury. These differences may reflect differences in mechanisms of LT acclimation and LT tolerance. The concentrations of total and individual sugars did not show a clear pattern that could differentiate the boreal and temperate groups. Raffinose and, in three of the six species, stachyose showed the closest association with LT tolerance. Sugar concentrations, principally sucrose, decreased during mild weather, perhaps because of respiratory losses or phloem export, and increased after periods of freezing temperatures. Low-temperature acclimation in boreal species appears to follow a rigid program that may affect their ability to avoid excessive respiratory losses in the event of continued climate warming in boreal regions. PMID:18595849

Strimbeck, G Richard; Kjellsen, Trygve D; Schaberg, Paul G; Murakami, Paula F

2008-09-01

15

Use of the Dynamic Model for the Assessment of Winter Chilling in a Temperate and a Subtropical Climatic Zone of Chile / Utilización del Modelo Dinámico para Evaluar el Frío Invernal en una Localidad de Clima Templado y otra Subtropical de Chile  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Se evaluó el frío invernal acumulado en Santiago (33°34´ lat. Sur; 625 m.s.n.m.; Región Metropolitana) y Vicuña (30°02´ lat. Sur; 643 m.s.n.m.; Región de Coquimbo) durante las temporadas 2005 y 2006 aplicando tres diferentes modelos. El modelo de horas-frío (CH), actualmente empleado como indicador [...] agroclimático en Chile, resultó de poca utilidad para contrastar efectivamente la condición subtropical de Vicuña con la condición templada de Santiago. Al utilizar el modelo de Utah se obtuvieron valores negativos de marzo a mayo e incluso hasta el mes de junio en Vicuña, ya que, precisamente, con este modelo el efecto del frío es anulado por las altas temperaturas. Sin embargo, una modificación de este modelo, denominado Unidades de Frío Positivas (UPF), en que los valores negativos se omiten, mostró diferencias en el frío acumulado entre ambas regiones, pero las diferencias fueron pequeñas y se expresaron sólo a partir del mes de julio en adelante. La aplicación del Modelo Dinámico, que considera que el frío se acumula en forma irreversible, como quantum o Porciones de Frío (PF), mostró que el frío invernal acumulado en la Región Metropolitana es el doble que en la Región de Coquimbo, y que las diferencias se expresan desde los inicios del otoño, haciéndolo así particularmente aplicable para zonas subtropicales. En este trabajo se discuten las ventajas del modelo dinámico por sobre los otros modelos utilizados. Abstract in english Accumulated chilling was estimated by applying three different models to the hourly autumn-winter temperature records from Santiago (33°34 S lat; 625 m.a.s.l.) and Vicuña (30°02´ S lat; 643 m.a.s.l.) for the years 2005 and 2006. The model of chilling hours, currently used in Chile as an agroclimatic [...] indicator, was of limited use for effectively contrasting a subtropical condition (Vicuña) with a temperate area such as Santiago. The application of the Utah model gave negative values from March to May, and even up to June in Vicuña, since in this model the chilling effect is “negated” by warmer temperatures. However, a modified version of the Utah model named Positive Chilling Units (PCU), in which negative values are omitted, showed differences in the accumulated chilling between both regions, although these differences were of small magnitude and were noted only from July onwards. The Dynamic Model, which considers that chilling is irreversibly accumulated as quantum or Chill Portions (CP), showed that chilling in Santiago doubled that of Vicuña, and that these differences in location were already expressed at the beginning of autumn, confirming, thus, the suitability of the model for subtropical conditions. In this work the advantages of the dynamic model over other models are discussed.

Francisco J, Pérez; Juan, Ormeño N; Bryan, Reynaert; Sebastián, Rubio.

2008-06-01

16

Partially melted zone in Al-Mg-Si alloy gas tungsten arc welds: effect of techniques and prior thermal temper  

Energy Technology Data Exchange (ETDEWEB)

Influence of prior thermal temper and welding techniques on microstructure changes in the partially melted zone (PMZ) of AA6061 alloy gas tungsten arc (GTA) welds was investigated. Welds of AA6061 in naturally aged (T4) and artificially aged (T6) thermal tempers were made by continuous current (CC) and pulsed current (PC) techniques of GTA welding. Optical, scanning electron microscopy and microhardness testing were carried out to study the PMZ in welds. Susceptibility to liquation was high in the T6 temper as compared to the T4 temper and was attributed to a greater amount of silicon rich eutectic at the grain boundaries of PMZ. The PC technique was found to improve the resistance to susceptibility to liquation in the PMZ of AA6061 alloy GTA welds and was due to the possible reduction in the peak temperature. (author)

Srinivasa Rao, K.; Prasad Rao, K.

2005-09-15

17

Phenological responses of Ulmus pumila (Siberian Elm) to climate change in the temperate zone of China.  

Science.gov (United States)

Using Ulmus pumila (Siberian Elm) leaf unfolding and leaf fall phenological data from 46 stations in the temperate zone of China for the period 1986-2005, we detected linear trends in both start and end dates and length of the growing season. Moreover, we defined the optimum length period during which daily mean temperature affects the growing season start and end dates most markedly at each station in order to more precisely and rationally identify responses of the growing season to temperature. On average, the growing season start date advanced significantly at a rate of -4.0 days per decade, whereas the growing season end date was delayed significantly at a rate of 2.2 days per decade and the growing season length was prolonged significantly at a rate of 6.5 days per decade across the temperate zone of China. Thus, the growing season extension was induced mainly by the advancement of the start date. At individual stations, linear trends of the start date correlate negatively with linear trends of spring temperature during the optimum length period, namely, the quicker the spring temperature increased at a station, the quicker the start date advanced. With respect to growing season response to interannual temperature variation, a 1°C increase in spring temperature during the optimum length period may induce an advancement of 2.8 days in the start date of the growing season, whereas a 1°C increase in autumn temperature during the optimum length period may cause a delay of 2.1 days in the end date of the growing season, and a 1°C increase in annual mean temperature may result in a lengthening of the growing season of 9 days across the temperate zone of China. Therefore, the response of the start date to temperature is more sensitive than the response of the end date. At individual stations, the sensitivity of growing season response to temperature depends obviously on local thermal conditions, namely, either the negative response of the start date or the positive response of the end date and growing season length to temperature was stronger at warmer locations than at colder locations. Thus, future regional climate warming may enhance the sensitivity of plant phenological response to temperature, especially in colder regions. PMID:21805230

Chen, Xiaoqiu; Xu, Lin

2012-07-01

18

Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies  

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Full Text Available The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward retreat of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been limited to South America and New Zealand, are not fully consistent with each other and may be complicated by influences from other climatic factors. Here we present the first high-resolution diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation in the equatorward margin of the westerly wind belt during the last 1400 yr. Inferred rainfall was relatively high ?1400–1200 cal yr BP, decreased until ?950 cal yr BP, and rose notably through the Little Ice Age with pulses centred on ?600, 530, 470, 330, 200, 90, and 20 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations were linked to changes in the westerlies. Equatorward drift of the westerlies during the wet periods may have influenced Atlantic meridional overturning circulation by restricting marine flow around the tip of Africa. Apparent inconsistencies among some aspects of records from South America, New Zealand and South Africa warn against the simplistic application of single records to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in the austral winter rainfall zones with future warming.

J. C. Stager

2012-05-01

19

Precipitation variability in the winter rainfall zone of South Africa during the last 1400 yr linked to the austral westerlies  

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Full Text Available The austral westerlies strongly influence precipitation and ocean circulation in the southern temperate zone, with important consequences for cultures and ecosystems. Global climate models anticipate poleward contraction of the austral westerlies with future warming, but the available paleoclimate records that might test these models have been largely limited to South America, are not fully consistent with each other, and may be complicated by influences from other climatic factors. Here we present the first fine-interval diatom and sedimentological records from the winter rainfall region of South Africa, representing precipitation during the last 1400 yr. Inferred rainfall increased ~1400–1200 cal yr BP and most notably during the Little Ice Age with pulses centered on ~600, 530, 470, 330, 200, and 90 cal yr BP. Synchronous fluctuations in Antarctic ice core chemistry strongly suggest that these variations are linked to changes in the westerlies. Partial inconsistencies among South African and South American records warn against the simplistic application of local-scale histories to the Southern Hemisphere as a whole. Nonetheless, these findings in general do support model projections of increasing aridity in austral winter rainfall zones with future warming.

J. C. Stager

2011-12-01

20

Long term CO2 enrichment in a temperate grassland increases soil respiration during late autumn and winter  

Science.gov (United States)

Soil respiration of terrestrial ecosystems, a major component in the global carbon cycle may comprise a potential positive feedback to elevated atmospheric CO2 concentrations. However, analyses reflecting seasonal variability of soil CO2 fluxes under long term CO2 enrichment including winter soil respiration are rare. At the Giessen free-air CO2 enrichment in a temperate grassland (Gi-FACE), adding +20% to the ambient CO2 concentration since 1998, we analyzed the seasonal dynamics of soil respiration including dormant seasons. We defined five seasons, with respect to management practices and phenological cycles. For a period of three years (2008-2010), we performed weekly measurements of soil respiration with an LI-8100 soil CO2 efflux survey chamber from four vegetation-free subplots per FACE or control plot and tested for a CO2 effect within the defined seasons. The results revealed a pronounced and repeated increase of soil respiration during winter dormancy. However, during spring and summer season, characterized by strong above- and below-ground plant growth, no significant change in soil respiration was observed at the Gi-FACE under elevated CO2. This suggests (i) that measuring soil respiration only during the vegetative growth period in CO2 enrichment experiments may underestimate the true soil-respiratory CO2 loss (i.e. overestimate the C sequestered), (ii) that additional C assimilated by plants during the growing period, getting transferred below-ground until autumn, will quickly be lost again via enhanced heterotrophic respiration during the off-season, driving the increased winter soil respiration under elevated CO2.

Keidel, Lisa; Moser, Gerald; Kammann, Claudia; Grünhage, Ludger; Müller, Christoph

2014-05-01

 
 
 
 
21

Sensitivity of Winter/Spring Hydrologic Processes to Climate Change in a Temperate Climate  

Science.gov (United States)

Wisconsin's hydrology is dominated by winter/spring processes. While winter precipitation totals are lower than during the summer months, the accumulation of water in snowpack and its subsequent release onto frozen soils during the spring melt event make temperature-related processes responsible for many of the largest floods in the state, and the majority of annual groundwater recharge. We developed warming scenarios based on the downscaled GCM data available from the North American Regional Climate Change Assessment Program, which were then applied to a one-dimensional physical-process hydrologic and thermal model, Simultaneous Heat and Water (SHAW). SHAW was selected as one of the few hydrologic models capable of modeling soil frost formation and melting, and its impacts on infiltration and runoff. Preliminary results suggest that reduced snowpack and frost formation will lead to a significant reduction in surface runoff and a commensurate increase in groundwater recharge. This could have profound impacts on the hydrology and ecology of the region, increasing baseflows, decreasing the variability of streamflows, and raising groundwater levels. Understanding these impacts will be We intend to apply our modeled outputs to the statistics defined in the Indicators of Hydrologic Alteration package developed by the Nature Conservancy as a way to quantify the impacts of air temperature changes on hydrology in the region. As we move forward we will be looking for tipping points and threshold behavior that can help scientists understand the changing system and help guide conservation and development planning.

Murdock, E.; Potter, K. W.

2012-12-01

22

Tropical Agroecosystems: These habitats are misunderstood by the temperate zones, mismanaged by the tropics.  

Science.gov (United States)

I have listed some of the ways in which the lowland tropics are not such a warm and wonderful place for the farmer, some of the reasons why it may be unreasonable to expect him to cope with the problems, and some of the ways in which the temperate zones make his task more difficult. The tropics are very close to being a tragedy of the commons on a global scale (69, 103), and it is the temperate zone's shepherds and sheep who are among the greatest offenders (31). Given that the temperate zones have some limited amount of resources with which they are willing to repay the tropics, how can these resources best be spent? The first answer, without doubt, is education, and the incorporation of what is already known about the tropics into that education. Second should be the generation of secure psychological and physical resources for governments that show they are enthusiastic about the development of an SYTA. Third should be support of intensive research needed to generate the set of site-specific rules for specific, clearly identified SYTA's. The subject matter of youths' cultural programming is presumably determined by what they will need during the rest of their lives. A major component of this programming should be the teaching of the socioeconomic rules of a sustained-yield, nonexpanding economy, tuned to the concept of living within the carrying capacity of the country's or region's resources. Incorporating such a process into tropical school systems will cause a major upheaval, if for no other reason than that it will involve an evaluation of the country's resources, what standard of living is to be accepted by those living on them, and who is presently harvesting them. Of even greater impact, it will have to evaluate resources in terms of their ability to raise the standard of living by Y amount for X proportion of the people in the region, rather than in terms of their cash value on the world market. For such a change to be technologically successful, it will require a great deal of pantropical information exchange. This information exchange will cost a great deal of resource, not only in travel funds and support of on-site study, but in insurance policies for the countries that are willing to take the risk of trying to change from an exploitative agroecosystem to an SYTA. For such an experiment to be sociologically successful, it will require a complete change in tropical educational systems, from emphasizing descriptions of events as they now stand, to emphasizing analysis of why things happen the way they do. This will also be very expensive, not only in retreading the technology and mind-sets of current teaching programs, but in gathering the facts on why the tropics have met their current fate. There is a surfeit of biological and agricultural reports dealing with ecological experiments and generalities which suggest that such and such will be the outcome if such and such form of resource harvest is attempted. It is clear that human desiderata regarding a particular site are often radically different from the needs of the "average" wild animals and plants that formed the basis for such experiments and generalities. A finely tuned SYTA will come close to providing a unique solution for each region. The generalities that will rule it are highly stochastic. The more tropical the region, the more evenly weighted the suboutcomes will be, and thus the more likely each region will be to have a unique overall outcome. For example, it is easy to imagine four different parts of the tropics, each with the same kind of soil and the same climate, with four different, successful SYTA's, one based on paddy rice, one on shelterwood forestry, one on tourism, and one on shifting maize culture. A regional experiment station working holistically toward an SYTA is potentially one of the best solutions available. As currently structured, however, almost all tropical experiment stations are inadequate for such a mission. Most commonly they are structured around a single export crop such as coffee, sugar, rubber, cotton, ca

Janzen, D H

1973-12-21

23

Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper  

International Nuclear Information System (INIS)

Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ

24

Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper  

Energy Technology Data Exchange (ETDEWEB)

Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ.

Rao, K. Srinivasa [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)]. E-mail: arunaraok@yahoo.com; Reddy, G. Madhusudan [Defense Metallurgical Research Laboratory, Hyderabad 500258 (India); Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)

2005-08-25

25

Larval fish dynamics in the Nxaxo-Ngqusi Estuary Complex in the warm temperate–subtropical transition zone of South Africa  

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Full Text Available The larval fish assemblage was investigated in the permanently open Nxaxo-Ngqusi Estuary Complex, situated in the subtropical–warm temperate biogeographic boundary zone of South Africa. Larval and early juvenile fishes were collected in summer and winter of 2007 and 2008 using a mixed method approach by boat-based plankton tows in mid-channel waters and seine net hauls along the margins. In total, 20 455 fishes were collected representing 21 families and 40 taxa, of which 13 900 fishes were from mid-channel sites (15 families and 21 taxa. Seine net hauls along the estuary margins produced 6550 fishes representing 18 families and 33 taxa. Gobiidae was the dominant fish family in the mid-channel waters followed by the Clupeidae whereas the opposite was found in marginal waters. Estuary-resident larvae were the dominant group in the estuary complex. The catches typically reflected a more warmtemperate community, although subtropical-associated species were present. Fish density in mid-channel waters was higher in the Ngqusi arm than that of the Nxaxo arm, whereas along the marginal waters, CPUE was higher in the latter. Fish densities in mid-channel waters and PUE along the margins were typically higher in summer.

T.H. Wooldridge

2011-10-01

26

Radiocarbon and stable carbon isotope compositions of chemically fractionated soil organic matter in a temperate-zone forest  

International Nuclear Information System (INIS)

To better understand the role of soil organic matter in terrestrial carbon cycle, carbon isotope compositions in soil samples from a temperate-zone forest were measured for bulk, acid-insoluble and base-insoluble organic matter fractions separated by a chemical fractionation method. The measurements also made it possible to estimate indirectly radiocarbon (14C) abundances of acid- and base-soluble organic matter fractions, through a mass balance of carbon among the fractions. The depth profiles of 14C abundances showed that (1) bomb-derived 14C has penetrated the first 16 cm mineral soil at least; (2) ?14C values of acid-soluble organic matter fraction are considerably higher than those of other fractions; and (3) a significant amount of the bomb-derived 14C has been preserved as the base-soluble organic matter around litter-mineral soil boundary. In contrast, no or little bomb-derived 14C was observed for the base-insoluble fraction in all sampling depths, indicating that this recalcitrant fraction, accounting for approximately 15% of total carbon in this temperate-zone forest soil, plays a role as a long-term sink in the carbon cycle. These results suggest that bulk soil organic matter cannot provide a representative indicator as a source or a sink of carbon in soil, particularly on annual to decadal timescales

27

Benthic assemblages of a temperate estuarine system in South America: Transition from a freshwater to an estuarine zone  

Science.gov (United States)

The objectives of the present study were to describe the species composition, diversity and distribution of the zoobenthic assemblages, to estimate the abundance and biomass of the dominant species, and to identify the main environmental factors determining the distribution patterns of the invertebrates from a freshwater to an estuarine zone in a temperate estuary of South America. The Río de la Plata estuary is a microtidal system characterized by a high concentration of suspended solids. Fifty-three taxa of meso- and macro-invertebrates were identified in the samples collected during November and December 2001. Molluscs, annelids, crustaceans and nematodes were found at 90% of the sampling sites. Molluscs comprised up to about 90% of the total zoobenthos biomass: the remaining percentage corresponded mainly to annelids and less to nematodes and crustaceans. An ecocline along the salinity gradient could be observed for the benthic assemblages from the freshwater to the estuarine zone in Rio de la Plata. A Canonical Correspondence Analysis shows that results from sampling sites in the outer zone were strongly related to salinity, depth and pH and less to oxygen and percentage of clay. The results from stations in the inner zone, and part of the middle zone, were mainly related to the occurrence of sand and contents of NH 4+-N, NO 3--N, and PO 43--P.

Cortelezzi, Agustina; Capítulo, Alberto Rodrigues; Boccardi, Lucía; Arocena, Rafael

2007-12-01

28

Effect of low winter temperatures on milk production of dairy cows grazed on farms in a warm temperate climate (Australia)  

Science.gov (United States)

Two-day milk production figures for dairymen at Armidale (31° S Lat.) and Goulburn (35° S Lat.), Australia, were compared with minimum daily temperatures. Comparisons were made between production levels on days with temperatures above and below 0°C, and between days with varying intensities of cold: differences in production were minor. The infrequent, more prolonged periods of cold weather (“cold” being days on which the minimum temperature was below 0°C) were also associated with only very slight reductions in milk output; and the most pronounced decline in production was not attributable to low temperatures. Although short-term fluctuations in output were not related to low temperature events or low temperatures in combination with rain, thermal stress on plant growth during winter contributed to a seasonal downturn in production and below-average annual milk yields in areas with low winter temperatures.

Dragovich, D.

1980-06-01

29

Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil  

Science.gov (United States)

Soil moisture strongly controls the uptake of atmospheric methane by limiting the diffusion of methane into the soil, resulting in a negative correlation between soil moisture and methane uptake rates under most non-drought conditions. However, little is known about the effect of water stress on methane uptake in temperate forests during severe droughts. We simulated extreme summer droughts by exclusion of 168 mm (2001) and 344 mm (2002) throughfall using three translucent roofs in a mixed deciduous forest at the Harvard Forest, Massachusetts, USA. The treatment significantly increased CH4 uptake during the first weeks of throughfall exclusion in 2001 and during most of the 2002 treatment period. Low summertime CH4 uptake rates were found only briefly in both control and exclusion plots during a natural late summer drought, when water contents below 0.15 g cm-3 may have caused water stress of methanotrophs in the A horizon. Because these soils are well drained, the exclusion treatment had little effect on A horizon water content between wetting events, and the effect of water stress was smaller and more brief than was the overall treatment effect on methane diffusion. Methane consumption rates were highest in the A horizon and showed a parabolic relationship between gravimetric water content and CH4 consumption, with maximum rate at 0.23 g H2O g-1 soil. On average, about 74% of atmospheric CH4 was consumed in the top 4-5 cm of the mineral soil. By contrast, little or no CH4 consumption occurred in the O horizon. Snow cover significantly reduced the uptake rate from December to March. Removal of snow enhanced CH4 uptake by about 700-1000%, resulting in uptake rates similar to those measured during the growing season. Soil temperatures had little effect on CH4 uptake as long as the mineral soil was not frozen, indicating strong substrate limitation of methanotrophs throughout the year. Our results suggest that the extension of snow periods may affect the annual rate of CH4 oxidation and that summer droughts may increase the soil CH4 sink of temperate forest soils. ?? 2005 Elsevier Ltd. All rights reserved.

Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

2006-01-01

30

Molecular data and ecological niche modelling reveal the phylogeographic pattern of Cotinus coggygria (Anacardiaceae) in China's warm-temperate zone.  

Science.gov (United States)

The phylogeography of common and widespread species helps to elucidate the history of local flora and vegetation. In this study, we selected Cotinus coggygria, a species widely distributed in China's warm-temperate zone. One chloroplast DNA (cpDNA) region and ecological niche modelling were used to examine the phylogeographic pattern of C. coggygria. The cpDNA data revealed two phylogeographic groups (Southern and Northern) corresponding to the geographic regions. Divergence time analyses revealed that divergence of the two groups occurred at approximately 147,000 years before the present (BP), which coincided with the formation of the downstream area of the Yellow River, indicating that the Yellow River was a weak phylogeographic divide for C. coggygria. The molecular data and ecological niche modelling also indicated that C. coggyria did not experience population expansion after glaciations. This study thus supports the fact that Pleistocene glacial cycles only slightly affected C. coggygria, which survived in situ and occupied multiple localised glacial refugia during glaciations. This finding is contrary to the hypothesis of large-scale range habitat contraction and retreat into a few main refugia. PMID:24494998

Wang, W; Tian, C Y; Li, Y H; Li, Y

2014-11-01

31

Tidal and spatial variations of DI13C and aquatic chemistry in a temperate tidal basin during winter time  

Science.gov (United States)

Here, the pelagic carbonate system and the ?13C signature of dissolved inorganic carbonate (DIC) were investigated in a tidal basin of the southern North Sea, the Jade Bay, with respect to tidal cycles and a transect towards the North Sea in winter time (January and November, 2010). Physical parameters, major and trace elements, and nutrient concentrations were considered, too. Primary production and pelagic organic matter respiration were negligible during winter time. Both, the compositional variations on the transects as well as during the tidal cycles indicate the mixing of North Sea with fresh water. The combined spatial co-variations of different parameters indicate an introduction of fresh water that was enriched in DI12C, metabolites (e.g., ammonia), protons, and dissolved redox-sensitive elements (e.g., Mn2 +). During the January campaign, the discharge via the flood gates was limited due to ice cover of the hinterland drainage ditches, allowing for an observation of tidal variations without significant mixing contributions from surface water discharges. Considering a binary mixing model with North Sea and fresh water as end-members, the extrapolated fresh water end-member composition for this campaign is estimated to contain about 3.8 mmol/kg DIC (?13C ? - 10 ± 1‰ vs. VPDB), and enhanced concentrations of NH4+, Mn2 +, and protons compared to North Sea water. The fast temporal response of dissolved geochemical tracers on tidal variations in the Jade Bay indicates a continuous supply of a fresh water component. The measured composition of fresh waters entering the Jade Bay via flood gates (end of October, 2010) did not match the values estimated by the binary mixing model. Therefore, the overall fresh water component likely is a mixture between sources originating from flood gates and (in January) dominating submarine groundwater discharge entering the Jade Bay. This model is consistent with the results obtained during the November campaign, when a more important contribution from flood gates is expected and a more variable fresh water end-member is estimated. The co-variations of the concentrations and the stable carbon isotope composition of DIC are applied to evaluate possible superimposed sink-source-transformation processes in the coastal waters and a general co-variation scheme is suggested.

Winde, V.; Böttcher, M. E.; Escher, P.; Böning, P.; Beck, M.; Liebezeit, G.; Schneider, B.

2014-01-01

32

Biological soil crusts are the main contributor to winter soil respiration in a temperate desert ecosystem of China  

Science.gov (United States)

Aims Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. However, most studies carried out to date on carbon (fluxes) in these ecosystems, such as soil respiration (RS), have neglected them. Also, winter RS is reported to be a significant component of annual carbon budget in other ecosystems, however, we have less knowledge about winter RS of BSCs in winter and its contribution to carbon cycle in desert regions. Therefore, the specific objectives of this study were to: (i) quantify the effects of different BSCs types (moss crust, algae crust, physical crust) on the winter RS; (ii) explore relationships of RS against soil temperature and water content for different BSCs, and (iii) assess the relative contribution of BSCs to the annual amount of C released by RS at desert ecosystem level. Methods Site Description The study sites are located at the southeast fringe of the Tengger Desert in the Shapotou region of the Ningxia Hui Autonomous Region [37°32'N and 105°02'E, at 1340 m above mean sea level (a.m.s.l.)], western China. The mean daily temperature in January is -6.9°C , while it is 24.3°C in July. The mean annual precipitation is 186 mm, approximately 80% of which falls between May and September. The annual potential evaporation is 2800 mm. The landscape of the Shapotou region is characterized by large and dense reticulate barchans chains of sand dunes that migrate south-eastward at a velocity of 3-6 m per year. The soil is loose, infertile and mobile and can thus be classified as orthic sierozem and Aeolian sandy soil. Additionally, the soil has a consistent gravimetric water content that ranges from 3 to 4%. The groundwater in the study area is too deep (>60 m) to support large areas of the native vegetation cover; therefore, precipitation is usually the only source of freshwater. The predominant native plants are Hedysarum scoparium Fisch. and Agriophyllum squarrosum Moq., Psammochloa cillosa Bor, which scattered distribute with cover about 1% of the entire study area. Prior to revegetation, straw-checkerboards approximately 1×1 m2 in area were constructed using wheat or rice straw to stabilize the dune surface and allow time for the planted xerophytic shrubs to adapt to the new environment. In 1956, the following 2-year-old xerophytic shrub seedlings were planted within the checkerboard at a density of 16 individuals per 100 m2 and grown without irrigation: Artemisia ordosica Krasch, H. scoparium Fisch, Calligonum mongolicum Turc'z, Caragana microphylla Lam., Caragana korshinskii Kom, Salix gordejevii and Atraphaxis bracteata A.Los. The stabilized area was then expanded to parallel areas in 1964 and 1982 using the same method and species. As a result, the initial stages of change that have occurred at these sites were similar. After more than fifties years succession, the predominant plants are semi-shrubs, shrubs, forbs, and grasses at present and BSCs formed. The common BSCs in the region may be dominated by cyanobacteria, algae, lichens and mosses, or any combination of these organisms. Cyanobacteria species include Microcolous vaginatus Gom., Hydrocoleus violacens Gom., Lyngbya crytoraginatus Schk., Phormidium amblgum Gom., P. autumnale (Ag.) Gom., P. foveolarum (Mont.) Gom. and Phormidium luridum (Kutz) Gom. etc; algal species mainly include Anabaena azotica Ley, Euglena sp., Hantzschia amphioxys var capitata Grum, Oscillatoria obscura Gom., O. pseudogeminate G. Schm. And Scytonema javanicum (Kutz) Bornet Flash etc; lichen species include Collema tenax (Sw.) Ach., Endocarpon pusillum Hedw.; and moss species are dominated by Bryum argenteum Hedw., Didymodon constrictus (Mitt.) Saito., Tortula bidentata Bai Xue Liang and T. desertorum Broth.. Experimental Design and Rs measurements On October 2010, We selected the moss-dominated BSCs at four revegetation sites and natural vegetation sites, in which 3 replicated plots were selected randomly. In each plot, olyvinyl chloride (PVC) collar (lenth 10 cm, internal diameter 10cm ) were inserted 7 cm into the soil. During the

He, M. Z.

2012-04-01

33

Prediction of gas/particle partition quotients of Polybrominated Diphenyl Ethers (PBDEs) in north temperate zone air: an empirical approach.  

Science.gov (United States)

Gas/particle (G/P) partitioning process is an important factor governing the transport and fate of chemicals in the atmosphere. Based on a large dataset of more than 700 pairs of air samples in gaseous and particulate phases with a wide ambient temperature range of 60°C from -22°C to +38°C obtained from our Chinese POPs Soil and Air Monitoring Program, Phase 2 (China-SAMP-II), we investigated G/P partitioning behavior of polybrominated diphenyl ether (PBDEs) in Chinese air. We derived for the first time empirical equations to predict the values of slopes and intercepts for both subcooled-liquid-vapor-pressure (PL)-based and octanol-air-partition-coefficient (KOA)-based models as functions of temperature, and thus predicted partition quotient (KP) without assuming an equilibrium status and free of artifacts. These equations have been successfully applied to predict the values of KP for PBDEs in air of China and other countries in the north temperate zone (NTZ) and also at an Arctic site in East Greenland, and our results matched the monitoring data well at background, rural, urban, and suburban sites, but not at e-waste sites due to the unpredictable PBDE emissions at these sites. Our equations predicted that the ranges of slopes were 0.02-0.82 for logKP-logKOA plots and -0.82 to -0.02 for logKP-logPL plots at temperatures ranged of 60°C from -22°C to +38°C. Our new KOA-based equation was compared with the Harner-Bidleman equation that was derived at a condition of equilibrium, and the results indicated that our new equation has a better performance than the Harner-Bidleman equation in describing G/P partitioning behavior of PBDEs in air as functions of logKOA. We also found for the first time that the G/P partitioning of PBDE congeners would become saturated in the particulate phase respect to the gas phase if the ambient temperature is low enough. A criterion to classify the equilibrium and nonequilibrium status for PBDEs was also established using logKOA. The study presented in this paper provides a useful tool for environmental scientists in both monitoring and modeling research on G/P partitioning behavior for PBDEs in air. PMID:25042246

Li, Yi-Fan; Jia, Hong-Liang

2014-10-01

34

Holocene climate variability in the winter rainfall zone of South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the winter rainfall zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 cal years BP most likely in response to a northward shift of the austral westerlies. Wet phases and strengthened coastal water upwellings are companied by a decrease of Agulhas water leakage into the South Atlantic and a reduced dust incursion over Antarctica, as indicated in previous studies. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS between 9000 and 5500 cal years BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the eastern South Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in the South Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation.

S. Weldeab

2013-10-01

35

Holocene climate variability in the winter rainfall zone of South Africa  

Science.gov (United States)

We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral) from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the winter rainfall zone (WRZ) of South Africa occurred during the "Little Ice Age" (700-100 cal years BP) most likely in response to a northward shift of the austral westerlies. Wet phases and strengthened coastal water upwellings are companied by a decrease of Agulhas water leakage into the South Atlantic and a reduced dust incursion over Antarctica, as indicated in previous studies. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS) between 9000 and 5500 cal years BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the eastern South Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in the South Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation.

Weldeab, S.; Stuut, J.-B. W.; Schneider, R. R.; Siebel, W.

2013-10-01

36

Holocene climate variability in the Winter Rainfall Zone of South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes and grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with increase of dust deposition over Antarctica and an enhanced leakage of warm Agulhas water into the southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and leakage of warm water in southern Atlantic, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.

S. Weldeab

2013-05-01

37

Selection on a eumelanic ornament is stronger in the tropics than in temperate zones in the worldwide-distributed barn owl.  

Science.gov (United States)

Spatial variation in the pattern of natural selection can promote local adaptation and genetic differentiation between populations. Because heritable melanin-based ornaments can signal resistance to environmentally mediated elevation in glucocorticoids, to oxidative stress and parasites, populations may vary in the mean degree of melanic coloration if selection on these phenotypic aspects varies geographically. Within a population of Swiss barn owls (Tyto alba), the size of eumelanic spots is positively associated with survival, immunity and resistance to stress, but it is yet unknown whether Tyto species that face stressful environments evolved towards a darker eumelanic plumage. Because selection regimes vary along environmental gradients, we examined whether melanin-based traits vary clinally and are expressed to a larger extent in the tropics where parasites are more abundant than in temperate zones. To this end, we considered 39 barn owl species distributed worldwide. Barn owl species living in the tropics displayed larger eumelanic spots than those found in temperate zones. This was, however, verified in the northern hemisphere only. Parasites being particularly abundant in the tropics, they may promote the evolution of darker eumelanic ornaments. PMID:19032496

Roulin, A; Wink, M; Salamin, N

2009-02-01

38

Holocene climate variability in the winter rainfall zone of South Africa  

Directory of Open Access Journals (Sweden)

Full Text Available We established a multi-proxy time series comprising analyses of major elements in bulk sediments, Sr and Nd isotopes, grain size of terrigenous fraction, and ?18O and ?13C in tests of Neogloboquadrina pachyderma (sinistral from a marine sediment sequence recovered off the Orange River. The records reveal coherent patterns of variability that reflect changes in wind strength, precipitation over the river catchments, and upwelling of cold and nutrient-rich coastal waters off Western South Africa. The wettest episode of the Holocene in the Winter Rainfall Zone (WRZ of South Africa occurred during the "Little Ice Age" (700–100 yr BP. Wet phases were accompanied by strengthened coastal water upwellings, a decrease of Agulhas water leakage into the Southern Atlantic, and a reduced dust incursion over Antarctica. A continuous aridification trend in the WRZ and a weakening of the Southern Benguela Upwelling System (BUS between 9000 and 5500 yr BP parallel with evidence of a poleward shift of the austral mid-latitude westerlies and an enhanced leakage of warm Agulhas water into the Southeastern Atlantic. The temporal relationship between precipitation changes in the WRZ, the thermal state of the coastal surface water, and variation of dust incursion over Antarctica suggests a causal link that most likely was related to latitudinal shifts of the Southern Hemisphere westerlies and changes in the amount of Agulhas water leakage into the Southern BUS. Our results of the mid-Holocene time interval may serve as an analogue to a possible long-term consequence of the current and future southward shift of the westerlies that may result in a decline of rainfall over Southwest Africa and a weakened upwelling with implication for phytoplankton productivity and fish stocks. Furthermore, warming of the coastal surface water as a result of warm Agulhas water incursion into the Southern BUS may affect coastal fog formation that is critical as moisture source for the endemic flora of the Namaqualand.

S. Weldeab

2012-06-01

39

Winter stream temperature in the rain-on-snow zone of the Pacific northwest: influences of hillslope runoff and transient snow cover  

Directory of Open Access Journals (Sweden)

Full Text Available Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1 winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2 stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms the effects of energy exchanges at the stream surface during rain and rain-on-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that climatic warming may generate higher winter stream temperatures in the rain-on-snow zone due to both increased rain temperature and reduced cooling effect of snow cover.

J. A. Leach

2013-10-01

40

Control of Saharan mineral dust transport to Barbados in winter by the Intertropical Convergence Zone over West Africa  

Science.gov (United States)

The reasons for the inter-annual variability of dust transport from the Sahara across the Atlantic are not well-understood. Here we address this issue by defining three new climate indices that capture the position and intensity of the zone of near-surface convergence over West Africa, a part of the global Intertropical Convergence Zone (ITCZ). We then relate these indices to a 38-year record of mineral dust concentrations at Barbados focusing on the winter season. The results show that the latitudinal displacement of the ITCZ over West Africa and the dust load in Barbados are statistically significantly correlated with a correlation coefficient ofr= -0.69. A southward movement of the ITCZ corresponds to an increased dust load at Barbados. This correlation represents an improvement upon previous results, which focused on traditional teleconnection indices such as the North Atlantic Oscillation or the El-Niño-Southern Oscillation. From analyzing composites of wind and precipitation we conclude that for the winter season, the inter-annual variability of the Barbados dust load is related to changes in near-surface northeasterly winds in semi-arid regions in North Africa coincident with the movement of the ITCZ. Changes in precipitation appear to only play a minor role.

Doherty, O. M.; Riemer, N.; Hameed, S.

2012-10-01

 
 
 
 
41

Long series relationships between global interannual CO2 increment and climate: evidence for stability and change in role of the tropical and boreal-temperate zones.  

Science.gov (United States)

Interannual variability in global CO2 increment (averaged from the Mauna Loa and South Pole Stations) shows certain strong spatial relationships to both tropical and temperate temperatures. There is a fairly strong positive year-round correlation between tropical mean annual temperatures (leading by 4 months) and annual CO2 throughout the time series since 1960, agreeing with the generally held view that the tropics play a major role in determining inter-annual variability in CO2 increment, with a major CO2 pulse following a warm year in the tropics. This 'almost no lag' climatic response is very strong during winter and relatively stable in time. However, the correlation with tropical temperature appears to have weakened in the first years of the 1990s in correspondence of the Pinatubo eruption and the positive phase of the AO/NAO. A secondary concurrent temperature signal is linked to summer variations of north temperate belt. Northern summer temperatures in the region 30-60 degrees N-and especially in the land area corresponding to the central east USA-have become relatively more closely correlated with CO2 increment. This trend has become increasingly stronger in recent years, suggesting an increasing role for growing season processes in the northern midlatitudes in affecting global CO2 increment. Once non-lagged annual tropical temperature variations are accounted for, terrestrial ecosystems, especially the temperate-boreal biomes, also show a coherent large scale lagged response. This involves an inverse response to annual temperature of preceding years centered at around 2 years before. This lagged response is most likely linked to internal biogeochemical cycles, in particular N cycling. During the study period north boreal ecosystems show a strengthening of the lagged correlation with temperature in recent years, while the lagged correlation with areas of tropical ecosystems has weakened. Residuals from a multiple correlations based on these climatic signals are directly correlated with SO, confirming an additional important role of upwelling in interannual variability of CO2 increment. Cooler summers following the Pinatubo eruption and the possible influence of the North Atlantic Oscillation (NAO/AO) are discussed as factors responsible for the shift in the relative importance of different regions over time during the series of data. PMID:15878607

Adams, Jonathan M; Piovesan, Gianluca

2005-06-01

42

Uptake of and follow-up supply with [benzene ring-U-14C]triademinol via the caryopsis and from dressed zones after seed treatment of winter barley and winter wheat using a dry dressing formula  

International Nuclear Information System (INIS)

The paper on hand studies the following issues: 1) What is the course of uptake of the agent and/or its metabolites into the plant following dry seed treatment of winter barley and winter wheat with [benzene ring-U-14C] triadimenol and sowing in the top-soil of a loess-based grey-brown podzolic soil. 2) What is the relevance of uptake and follow-up supply from the dressed zones of plants in neighbouring rows. 3) What is the extent of uptake and follow-up supply via the roots from dressed zones of neighbouring plants within the same row. 4) What is the course of dressed-zone formation following dry treatment of winter barley and winter wheat and sowing in the top-soil of a loess-based grey-brown podzolic soil. 5) What is the quantitative distribution of the agent on the pericarp of winter wheat caryopses following dry seed treatment. 6) Will the 14C-labelled agent be taken up, too, via the caryopsis and be translocated in scion and root. 7) What are the pathways of the agent from the caryopsis into the embryo. 8) How long will follow-up supply via the scutellum continue. The results concerning issues 1 to 4 were taken from tests with field lysimeters. Experiments concerning issues 6-8 were performed without soil in an climatic chamber. (orig./MG)

43

``Winter'' aggregations, colony cycle, and seasonal phenotypic change in the paper wasp Polistes versicolor in subtropical Brazil  

Science.gov (United States)

Social wasps from temperate zones have clear annual colony cycles, and the young queens hibernate during winter. In the subtropics, the only previously reported evidence for the existence of “hibernation” is the facultative winter aggregations of females during harsh climate conditions. As in temperate-zone species analyzed so far, we show in this study that in the paper wasp, Polistes versicolor, a subtropical species, body size increases as an unfavorable season approaches. Our morphological studies indicate that larger females come from winter aggregations—that is, they are new queens. Multivariate analyses indicate that size is the only variable analyzed that shows a relationship to the differences. Given the absence of a harsh climate, we suggest that the occurrence of winter aggregations in tropical P. versicolor functions to allow some females to wait for better environmental conditions to start a new nest, rather than all being obliged to start a new nest as soon as they emerge.

Gobbi, Nivar; Noll, Fernando B.; Penna, Marcelo A. H.

2006-10-01

44

Temporal dynamics of soil organic carbon after land-use change in the temperate zone – carbon response functions as a model approach  

DEFF Research Database (Denmark)

Land-use change (LUC) is a major driving factor for the balance of soil organic carbon (SOC) stocks and the global carbon cycle. The temporal dynamic of SOC after LUC is especially important in temperate systems with a long reaction time. On the basis of 95 compiled studies covering 322 sites in the temperate zone, carbon response functions (CRFs) were derived to model the temporal dynamic of SOC after five different LUC types (mean soil depth of 30±6 cm). Grassland establishment caused a long lasting carbon sink with a relative stock change of 128±23% and afforestation on former cropland a sink of 116±54%, 100 years after LUC (mean±95% confidence interval). No new equilibrium was reached within 120 years. In contrast, there was no SOC sink following afforestation of grasslands and 75% of all observations showed SOC losses, even after 100 years. Only in the forest floor, there was carbon accumulation of 0.38±0.04 Mg ha-1 yr-1 in afforestations adding up to 38±4 Mg ha-1 labile carbon after 100 years. Carbon loss after deforestation (-32±20%) and grassland conversion to cropland (-36±5%), was rapid with a new SOC equilibrium being reached after 23 and 17 years, respectively. The change rate of SOC increased with temperature and precipitation but decreased with soil depth and clay content. Subsoil SOC changes followed the trend of the topsoil SOC changes but were smaller (25±5% of the total SOC changes) and with a high uncertainty due to a limited number of datasets. As a simple and robust model approach, the developed CRFs provide an easily applicable tool to estimate SOC stock changes after LUC to improve greenhouse gas reporting in the framework of UNFCCC.

Poeplau, Christopher; Don, Axel

2011-01-01

45

Field observations of climbing behavior and seed predation by adult ground beetles (Coleoptera: Carabidae) in a lowland area of the temperate zone.  

Science.gov (United States)

Granivory is a specialized food habit in the predominantly carnivorous beetle family Carabidae. Most studies of carabid granivory have been conducted under laboratory conditions; thus, our knowledge of the feeding ecology of granivorous carabids in the field is insufficient. I conducted field observations of climbing behavior and seed predation by adult carabids in a lowland area of eastern Japan, from early October to late November in 2008. This is the first systematic field observation of the feeding ecology of granivorous carabids in the temperate zone. In total, 176 carabid individuals of 11 species were observed, with 108 individuals feeding on plant seeds/flowers. Each carabid species was primarily observed feeding on a particular plant species. Frequently observed combinations were: Amara gigantea Motschulsky on Humulus scandens (Loureiro) Merrill (Moraceae) seed, Amara lucens Baliani on Artemisia indica Willdenow (Asteraceae) flower, and Amara macronota (Solsky) and Harpalus (Pseudoophonus) spp. on Digitaria ciliaris (Retzius) Koeler (Poaceae) seed. In all but one species, the sex ratio of individuals observed feeding was female-biased. In Am. gigantea and Am. macronota, a larger proportion of females than males ate seeds. In the three Amara species, copulations on plants, with the female feeding on its seeds/flowers, were often observed. These observations may indicate that, whereas females climb onto plants to feed on seeds, males climb to seek females for copulation rather than forage. Because granivorous carabids play important roles as weed-control agents in temperate agro-ecosystems, the present results would provide valuable basic information for future studies on this subject. PMID:22546452

Sasakawa, Kôji

2010-10-01

46

Evaluation on energy and thermal performance for residential envelopes in hot summer and cold winter zone of China  

International Nuclear Information System (INIS)

As a result of rapid economic growth in the last several decades, energy issue is becoming more and more important in today's world because of a possible energy shortage in the future; the usage of residential electricity has increased rapidly in China and building energy efficiency is included as one of the 10 key programs targeting energy efficiency improvement in the 11th Five-Year Plan. In response to the growing concerns about energy conservation in residential buildings and its implications for the environment, systematic evaluation on energy and thermal Performance for residential envelops (EETP) is put forward to assess the energy efficiency of envelop designs and to calculate the energy consumption of cooling and heating systems. Hot summer and cold winter zone of China was selected for EETP analysis because of its rigorous climatic and huge energy consumption. The correlations between EETPs and electricity consumptions in cooling season, heating season, and the whole year were built in Shanghai, Changsha, Shaoguan and Chengdu, which represent A, B, C and D subzone of hot summer and cold winter zone in China, respectively. Illustrations indicate that the algorithm is simple and effective, energy and thermal performance of residential envelopes can be evaluated easily. The maximum allowable values of EETPs were determined when just meeting the compulsory indices of Standard JGJ134-2001, the corresponding allowable EETPs were also gained when achieving different energy-saving degrees on basis of it. EETP method can suggest possible ways to improve the energy efficiency for envelope designs of new building and retrofits of existing buildings and provide governments some useful information for the establishment of new policy on energy efficiency buildings. It has important meanings to carry out sustainable residential building designs with high thermal comfort and low energy consumption.

47

Taming Tempers  

Science.gov (United States)

... temper troubles often have an active, strong-willed style and extra energy that needs to be discharged. ... you see positive behaviors. Try to be flexible. Parenting can be a tiring experience, but try not ...

48

Disease in the dark: molecular characterization of Polychromophilus murinus in temperate zone bats revealed a worldwide distribution of this malaria-like disease.  

Science.gov (United States)

For a better understanding of the complex coevolutionary processes between hosts and parasites, accurate identification of the actors involved in the interaction is of fundamental importance. Blood parasites of the Order Haemosporidia, responsible for malaria, have become the focus of a broad range of studies in evolutionary biology. Interestingly, molecular-based studies on avian malaria have revealed much higher species diversity than previously inferred with morphology. Meanwhile, studies on bat haemosporidian have been largely neglected. In Europe, only one genus (Polychromophilus) and two species have been morphologically described. To evaluate the presence of potential cryptic species and parasite prevalence, we undertook a molecular characterization of Polychromophilus in temperate zone bats. We used a nested-PCR approach on the cytochrome b mitochondrial gene to detect the presence of parasites in 237 bats belonging to four different species and in the dipteran bat fly Nycteribia kolenatii, previously described as being the vector of Polychromophilus. Polychromophilus murinus was found in the four bat species and in the insect vector with prevalence ranging from 4% for Myotis myotis to 51% for M. daubentoni. By sequencing 682 bp, we then investigated the phylogenetic relationships of Polychromophilus to other published malarial lineages. Seven haplotypes were found, all very closely related, suggesting the presence of a single species in our samples. These haplotypes formed a well-defined clade together with Haemosporidia of tropical bats, revealing a worldwide distribution of this parasite mostly neglected by malarial studies since the 1980s. PMID:21073585

Megali, A; Yannic, G; Christe, P

2011-03-01

49

Winter stream temperature in the rain-on-snow zone of the Pacific Northwest: influences of hillslope runoff and transient snow cover  

Directory of Open Access Journals (Sweden)

Full Text Available Stream temperature dynamics during winter are less well studied than summer thermal regimes, but the winter season thermal regime can be critical for fish growth and development in coastal catchments. The winter thermal regimes of Pacific Northwest headwater streams, which provide vital winter habitat for salmonids and their food sources, may be particularly sensitive to changes in climate because they can remain ice-free throughout the year and are often located in rain-on-snow zones. This study examined winter stream temperature patterns and controls in small headwater catchments within the rain-on-snow zone at the Malcolm Knapp Research Forest, near Vancouver, British Columbia, Canada. Two hypotheses were addressed by this study: (1 winter stream temperatures are primarily controlled by advective fluxes associated with runoff processes and (2 stream temperatures should be depressed during rain-on-snow events, compared to rain-on-bare-ground events, due to the cooling effect of rain passing through the snowpack prior to infiltrating the soil or being delivered to the stream as saturation-excess overland flow. A reach-scale energy budget analysis of two winter seasons revealed that the advective energy input associated with hillslope runoff overwhelms vertical energy exchanges (net radiation, sensible and latent heat fluxes, bed heat conduction, and stream friction and hyporheic energy fluxes during rain and rain-on-snow events. Historical stream temperature data and modelled snowpack dynamics were used to explore the influence of transient snow cover on stream temperature over 13 winters. When snow was not present, daily stream temperature during winter rain events tended to increase with increasing air temperature. However, when snow was present, stream temperature was capped at about 5 °C, regardless of air temperature. The stream energy budget modelling and historical analysis support both of our hypotheses. A key implication is that climatic warming may generate higher winter stream temperatures in the rain-on-snow zone due to both increased rain temperature and reduced cooling effect of snow cover.

J. A. Leach

2014-02-01

50

Weed infestation of crops in different soils in the protective zone of Roztocze National Park. Part I. Winter and spring cereals  

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Full Text Available The study on weed infestation of crops in different soils in the protective zone of RPN was conducted in the years 1991-1995. The characterization of weed infestation of winter and spring cereals was based on 306 phytosociological records. made with the use of Braun-Blanquet method. The degree of weed infestation in the fields in the protective zone of RPN depended on environment conditions. Both winter and spring cereals in majority of soils were most infested by: Cenaturea cyanus, Apera spica-venti and Vicia hirsta. In the lightest podsolic soils, made of loose sand and slightly loamy sand. winter and spring cereals were additionally infested by Equisetum arvense and two acidophylic species: Seleranthus annuus and Spergula arvensis. The crops in brown loess soil were infested by Matricaria maritima subsp. inodora. The most difficult weed species in brown soil formed from gaizes and limestone soil were: Convolvulus arvensis, Papaver rhoeas and Galium aparine. Moreover winter cercals in limestone soil showed high or medium infestation with Consolida regalis, Aethusa cynapium, Lathyrus tuberosus and low infestation with Apera spica-venti and Centaurea cyanus. Spring cereals were less infested than winter cereals. Apera spica-venti and Centaurea cyanus were less common with spring cereals than with winter cereals. Also, spring cereals showed high or medium infestation with Convolvulus arvensis. Spring cereals in some soil units were infested by Chenopodium album and Stellaria media. There was also higher infestation of spring cereals in limestone soils with Avena fatua, Veronica persica, Sinapis arvensis and Sonchus arvensis, compared to winter cereals in limestone soils.

Marta Ziemi?ska-Smyk

2004-12-01

51

Winter plankton assemblage in the ice edge zone of the Weddell and scotia seas: composition, biomass and spatial distributions  

Science.gov (United States)

As part of the Antarctic Marine Ecosystem Research in the Ice Edge Zone (AMERIEZ) program, we examined the biomass and distribution of phytoplankton and protozooplankton at an advancing ice edge in the Weddell and Scotia Seas during the early austral winter. The advance of ice cover, local melting of sea ice and advection of water masses, possibly from lower latitude regions, were the main sources of variability in the physical regime of the ice-edge zone. Analysis of the plankton assemblage showed phytoplankton biomass (PPC) in the upper 100 m ranging from 100 to 272 mg C m -2 and protozooplankton biomass (PZC) ranging from 177 to 410 mg C m -2. Autotrophic dinoflagellates dominated phytoplankton stocks, followed by other autotrophic nanoflagellates and diatoms in decreasing biomass. Heterotrophic flagellates dominated protozooplankton biomass followed by ciliates and sarcodines. The biomass of major groups comprising the planktonic assemblage was similar at most stations with the exception of one station where diatoms predominated. Integrated PPC and PZC showed no relationship to water column stability. Integrated autotrophic flagellate biomass was higher at open water stations than at ice-covered stations, but none of the other integrated group biomasses showed variations that could be related to ice cover or water mass characteristics. Analysis of discrete-depth samples indicated that all groups (except the sarcodines) showed near surface maxima, that total PPC, diatoms and autotrophic flagellates showed higher biomasses at ice-edge and open water stations than at ice-covered stations and that none of the heterotrophs showed variations related to ice cover. Some groups, however, showed differences that could be related to water mass characteristics, but this was less evident than was the effect of depth or ice cover. Comparison of species assemblages of diatoms and choanoflagellates among water column stations indicated variations that could be related to the differing cruise legs and water mass characteristics. Similar diatom assemblages were found in both ice and water, but higher concentrations occured in the ice assemblages. A few diatom species were found to be indicator species for ice versus water assemblages and to distinguish among the varying hydrographic regimes. Although phytoplankton stocks were higher at non ice-covered than at ice-covered stations, we were not able to see distinct differences between ice-edge stations and those north of the furthest ice extent. We hypothesize that advection of sea ice into water above the freezing point and subsequent melting of ice probably affected much of our study area, so that any effects of "enhanced production" in the ice-edge zone would have been difficult to resolve. Moreover, absolute primary production was very low, and based on the trophic composition of the planktonic assemblage and production estimates from our AMERIEZ colleagues, we concluded that neither algal nor bacterial production was sufficient to produce an enrichment of protozooplankton stocks in the ice-edge zone. Calculations of a carbon budget suggested bacterial production was a significant proportion of total production and that the nano- and microheterotrophs must predominate in the utilization of both phyto- and bacterioplankton production at the winter ice edge. An analysis of species assemblages suggested little advection of populations from lower latitude regions and supports the contention that material was apparently released from sea ice during localized melting events. This input of carbon biomass and detritus from ice may supply the carbon needed to support the high concentrations of heterotrophs observed in our study, but this interpretation is confounded because ice-edge heterotrophic plankton populations also may be enriched by seeding from sea ice.

Garrison, David L.; Buck, Kurt R.; Gowing, Marcia M.

1993-02-01

52

A study of energy performance and audit of commercial mall in hot-summer/warm-winter climate zone in China  

Energy Technology Data Exchange (ETDEWEB)

The building energy performance improvement of large-scale public buildings is very important to release China's energy shortage pressure. The aim of the study is to find out the building energy saving potentials of large-scale public and commercial buildings by energy audit. In this paper, the energy consumption, energy performance, and audit were carried out for a typical commercial mall, the so-called largest mall in Asia, located in a hot-summer and warm-winter climate zone. The total annual energy consumption reaches 210.01 kWh/m{sup 2}, of which lighting energy consumption accounts for 30.03 kWh/m{sup 2} and the lift and elevator energy consumption accounts for 40.46 kWh/m{sup 2}. It is by far higher than that of the average building energy consumption in the same category. However, the annual heating, ventilation, and air-conditioning (HVAC) energy consumption is only 87.19 kWh/m{sup 2} even though they run 24/7. It proves that the energy performance of the HVAC system is good. Therefore, the building energy savings potential mainly relies on reducing the excessive usage of lighting, lifts, and elevators.

Zhisheng, Li; Jiawen, Liao; Xiaoxia, Wang [School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, Guangdong, 510006 (China); Lin, Yaolin [Building Energy Solutions and Technologies, Inc, San Jose Office, San Jose, CA 95134 (United States); Xuhong, Liu [School of Architecture and Urban Planning, Guangdong University of Technology, Guangzhou, Guangdong, 510643 (China)

2013-08-15

53

Induction of photosynthesis and importance of limitations during the induction phase in sun and shade leaves of five ecologically contrasting tree species from the temperate zone.  

Science.gov (United States)

We examined the principal differences in photosynthetic characteristics between sun and shade foliage and determined the relative importance of biochemical and stomatal limitations during photosynthetic induction. Temperate-zone broadleaf and conifer tree species, ranging widely in shade tolerance, were investigated from one locality in the Czech Republic. The study species included strongly shade-tolerant Abies alba Mill. and Tilia cordata Mill., less shade-tolerant Fagus sylvatica L. and Acer pseudoplatanus L. and sun-demanding Picea abies (L.) Karst. In the fully activated photosynthetic state, sun foliage of all species had significantly higher maximum CO(2) assimilation rates, maximum stomatal conductance and maximum rates of carboxylation than shade foliage. Compared with shade leaves, sun leaves had significantly higher nocturnal stomatal conductances. In all species, shade foliage tended to have higher induction states 60 s after leaf illumination than sun foliage. Sun and shade foliage did not differ in the rate of disappearance of the transient biochemical limitation during the induction phase. Longer time periods were required to reach 90% photosynthetic induction and 90% stomatal induction in sun foliage than in shade foliage of the less shade-tolerant F. sylvatica and A. pseudoplatanus and in sun-demanding P. abies; however, in sun foliage of the strongly shade-tolerant species T. cordata and A. alba, the time needed for photosynthetic induction was similar to, or less than, that for shade foliage. Shade but not sun needles of P. abies and A. alba had significantly slower induction kinetics than the broadleaf tree species. Among species, the sun-demanding P. abies exhibited the shortest stomatal induction times in both sun and shade leaves. Independently of shade tolerance ranking, the transient stomatal and total limitations that characterize photosynthetic induction were relieved significantly earlier in shade foliage than in sun foliage. Sun foliage generally exhibited a hyperbolic photosynthetic induction response, whereas a sigmoidal induction response was more frequent in shade foliage. The different relative proportions of transient biochemical and stomatal limitations during photosynthetic induction in sun and shade foliage indicate an essential role of stomata in photosynthetic limitation during induction, mainly in shade foliage, with a consequent influence on the shape of the photosynthetic induction curve. PMID:17472946

Urban, Otmar; Kosvancová, Martina; Marek, Michal V; Lichtenthaler, Hartmut K

2007-08-01

54

Austral winter distributions of large tintinnid and large sarcodinid protozooplankton in the ice-edge zone of the Weddell/Scotia Seas  

Science.gov (United States)

Seasonal distribution and abundance data for large sarcodinid protozooplankton (Radiolaria, Foraminifera, Acantharia and the heliozoan Sticholonche spp.) and larger tintinnid ciliates (e.g., Laackmaniella spp.) are necessary for evaluating their roles in food webs and particle fluxes. As part of the Antarctic Marine Ecosystem Research in the Ice Edge Zone (AMERIEZ) project, we sampled these large (? 50 ?m) protozooplankton in the winter ice edge zone of the Scotia/Weddell Seas. Organisms alive at the time of capture were counted in large volume (60 1) water samples from 5 paired depths in the upper 210 m from 17 stations. Relationships between abundances and environmental factors in ice-covered, ice edge, and open waters were assessed with correlation, cluster, and multidimensional scaling analyses. Mean abundances of large tintinnids were less than 3150 per m 3, and mean abundances of the individual sarcodine groups were generally less than 1000 per m 3. The most pronounced distributional patterns were related to depth. In general, large tintinnids were more abundant in the colder waters from 0-85 m, a zone encompassed by the mixed layer and the euphotic zone. Acantharians were more abundant in this upper zone only in ice-covered waters. Radiolaria (predominantly phaeodarians) and the heliozoan Sticholonche spp. were more abundant from 115 to 210 m, a zone of warmer, more saline water. Foraminiferan distributions showed little pattern with depth. Results of the cluster analyses also suggested that depth was the most significant effect determining similarity among assemblages of large protozooplankton at the 17 stations. The few correlations between abundances of the groups and chlorophyll a probably reflect relationships more complex than grazing. Abundances of large tintinnids were higher in surface waters under the ice than at the ice edge or in open water. This could result from their feeding on algal cells released from the base of the ice or it may be a result of higher populations in the outflow of Weddell Sea water. There were no consistent abundance patterns among large sarcodines that could be related to ice cover. It is suggested that the combination of low winter productivity, a dynamic environment, and slower growth rates of these large protozoans may prevent them from responding to local enhanced production with increased abundances in the winter ice edge zone. Furthermore, although there is enhanced productivity at the ice edge, this signal may not reach the protozooplankton groups most abundant in the water layer below the euphotic zone.

Gowing, Marcia M.; Garrison, David L.

1991-07-01

55

The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain  

Energy Technology Data Exchange (ETDEWEB)

In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of {sup 15}N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. - Deep-rooted wheat can recycle nitrate leached from maize root zone in winter wheat-summer maize rotation system.

Zhou Shunli [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China)], E-mail: zhoushl@cau.edu.cn; Wu Yongcheng [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); College of Agronomy, Si Chuan Agricultural University, Yaan 625014 (China); Wang Zhimin [Key Laboratory of Crop Cultivation and Farming System, Ministry of Agriculture, College of Agronomy and Biotechnology, China Agricultural University, 2 West Yuanmingyuan Road, Beijing 100094 (China); Lu Laiqing; Wang Runzheng [Wuqiao Experimental Station, China Agricultural University, Hebei 061802 (China)

2008-04-15

56

The nitrate leached below maize root zone is available for deep-rooted wheat in winter wheat-summer maize rotation in the North China Plain  

International Nuclear Information System (INIS)

In winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation system in the North China Plain, maize roots do not extend beyond 1.2 m in the vertical soil profile, but wheat roots can reach up to 2.0 m. Increases in soil nitrate content at maize harvest and significant reductions after winter wheat harvest were observed in the 1.4-2.0 m depth under field conditions. The recovery of 15N isotope (calcium nitrate) from various (1.0, 1.2, 1.4, 1.6, 1.8 and 2.0 m) soil depths showed that deep-rooting winter wheat could use soil nitrate up to the 2.0 m depth. This accounted partially, for the reduced nitrate in the 1.4-2.0 m depth of the soil after harvest of wheat in the rotation system. - Deep-rooted wheat can recycle nitrate leached from maize root zone in winter wheat-summer maize rotation system

57

Potential effects of climate change on the temperate zones of North and South America Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur  

Directory of Open Access Journals (Sweden)

Full Text Available Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the summer. Our objective here was to evaluate how predictions of climate change from global circulation models will influence climatic patterns and by inference the distribution of temperate zone ecosystems in North and South America. Calculations of annual water deficits suggest that the area affected by very dry conditions will double as a result of climate change. This expansion will take place in the vicinity of the currently dry areas. Monthly water deficit calculations suggest that approximately half of the temperate zone on each continent is affected by at least one month of deficit. Under a doubled CO2 climate, these areas would expand to cover up to 77 % of the temperate zone of North America and up to 80 % of South America. The resulting changes to the current distribution of ecosystems will likely be an expansion of deserts at the expense of grasslands in North and South America and an expansion of grasslands at the expense of deciduous and boreal forest in North America. Our analyses assumed that future climatic changes will be encompassed by the predictions of our three doubled CO2 scenarios. The most likely situation is that actual changes, if they occur, will be different from our scenarios. Therefore, our analyses should be interpreted as indications of the sensitivity of portions of the North and South American temperate zones to increases in temperature. The key conclusion from our analyses is that any increase in temperature caused by climate change will result in expansion of the driest portions of both continentsBajo condiciones actuales, extensas áreas de las zonas templadas del oeste de América del Norte y del sur de América del Sur tienen regímenes climáticos áridos a subhúmedos, que son vulnerables a cambios climáticos inducidos por actividades humanas. Predicciones obtenidas a partir de modelos de circulación global bajo una duplicación del CO2 atmosférico sugieren grandes cambios en temperatura media anual, y cambios pequeños o nulos en la precipitación media anual y la proporción de precipitación estival. Nuestro objetivo fue evaluar cómo las predicciones de cambio climático obtenidas de modelos de circulación global influirán sobre los patrones climáticos, e inferir a partir de ello la distribución de los ecosistemas de las zonas templadas de América del Norte y del Sur. Cálculos de déficit hídrico anual sugieren que, debido al cambio climático, se duplicará el área afectada por condiciones muy secas. Esta expansión ocurrirá en las cercanías de las zonas áridas actuales. Cálculos mensuales de déficit hídrico sugieren que aproximadamente la mitad de la zona templada de cada continente se ve afectada por al menos un mes de déficit. Bajo un clima con doble CO2, estas áreas se expandirían y cubrirían hasta 77 % de las áreas templadas de América del Norte y hasta 80 % de América del Sur. Los cambios en la distribución de ecosistemas resultantes probablemente serán debidos a la expansión de los desiertos a expensas de los pastizales en América del Norte y del Sur, y la expansión de los pastizales a expensas de los bosques deciduos y boreales en América del Norte. Nuestros análisis asumen que los cambios climáticos futuros estarán abarcados por las predicciones de los tres escenarios de duplicación de CO2 que utilizamos. La situación más probable es que los cambios reales, si es que ocurren, serán distintos a nuestros escenarios. Por lo tanto, nuestros análisis deberán interpretarse como indicaciones de la sensibilidad de partes de las zonas

W.K. LAUENROTH

2004-09-01

58

Potential effects of climate change on the temperate zones of North and South America / Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Bajo condiciones actuales, extensas áreas de las zonas templadas del oeste de América del Norte y del sur de América del Sur tienen regímenes climáticos áridos a subhúmedos, que son vulnerables a cambios climáticos inducidos por actividades humanas. Predicciones obtenidas a partir de modelos de circ [...] ulación global bajo una duplicación del CO2 atmosférico sugieren grandes cambios en temperatura media anual, y cambios pequeños o nulos en la precipitación media anual y la proporción de precipitación estival. Nuestro objetivo fue evaluar cómo las predicciones de cambio climático obtenidas de modelos de circulación global influirán sobre los patrones climáticos, e inferir a partir de ello la distribución de los ecosistemas de las zonas templadas de América del Norte y del Sur. Cálculos de déficit hídrico anual sugieren que, debido al cambio climático, se duplicará el área afectada por condiciones muy secas. Esta expansión ocurrirá en las cercanías de las zonas áridas actuales. Cálculos mensuales de déficit hídrico sugieren que aproximadamente la mitad de la zona templada de cada continente se ve afectada por al menos un mes de déficit. Bajo un clima con doble CO2, estas áreas se expandirían y cubrirían hasta 77 % de las áreas templadas de América del Norte y hasta 80 % de América del Sur. Los cambios en la distribución de ecosistemas resultantes probablemente serán debidos a la expansión de los desiertos a expensas de los pastizales en América del Norte y del Sur, y la expansión de los pastizales a expensas de los bosques deciduos y boreales en América del Norte. Nuestros análisis asumen que los cambios climáticos futuros estarán abarcados por las predicciones de los tres escenarios de duplicación de CO2 que utilizamos. La situación más probable es que los cambios reales, si es que ocurren, serán distintos a nuestros escenarios. Por lo tanto, nuestros análisis deberán interpretarse como indicaciones de la sensibilidad de partes de las zonas templadas de América del Norte y del Sur a aumentos de temperatura. La principal conclusión de nuestros análisis es que cualquier aumento de temperatura debido a cambios climáticos resultará en una expansión de las porciones más áridas de ambos continentes Abstract in english Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling [...] of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the summer. Our objective here was to evaluate how predictions of climate change from global circulation models will influence climatic patterns and by inference the distribution of temperate zone ecosystems in North and South America. Calculations of annual water deficits suggest that the area affected by very dry conditions will double as a result of climate change. This expansion will take place in the vicinity of the currently dry areas. Monthly water deficit calculations suggest that approximately half of the temperate zone on each continent is affected by at least one month of deficit. Under a doubled CO2 climate, these areas would expand to cover up to 77 % of the temperate zone of North America and up to 80 % of South America. The resulting changes to the current distribution of ecosystems will likely be an expansion of deserts at the expense of grasslands in North and South America and an expansion of grasslands at the expense of deciduous and boreal forest in North America. Our analyses assumed that future climatic changes will be encompassed by the predictions of our three doubled CO2 scenarios. The most likely situation is that actual changes, if they occur, will be different f

W.K., LAUENROTH; H.E., EPSTEIN; J.M., PARUELO; I.C., BURKE; M.R., AGUIAR; O.E., SALA.

59

Potential effects of climate change on the temperate zones of North and South America / Potenciales efectos del cambio climático en zonas templadas de América del Norte y del Sur  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Bajo condiciones actuales, extensas áreas de las zonas templadas del oeste de América del Norte y del sur de América del Sur tienen regímenes climáticos áridos a subhúmedos, que son vulnerables a cambios climáticos inducidos por actividades humanas. Predicciones obtenidas a partir de modelos de circ [...] ulación global bajo una duplicación del CO2 atmosférico sugieren grandes cambios en temperatura media anual, y cambios pequeños o nulos en la precipitación media anual y la proporción de precipitación estival. Nuestro objetivo fue evaluar cómo las predicciones de cambio climático obtenidas de modelos de circulación global influirán sobre los patrones climáticos, e inferir a partir de ello la distribución de los ecosistemas de las zonas templadas de América del Norte y del Sur. Cálculos de déficit hídrico anual sugieren que, debido al cambio climático, se duplicará el área afectada por condiciones muy secas. Esta expansión ocurrirá en las cercanías de las zonas áridas actuales. Cálculos mensuales de déficit hídrico sugieren que aproximadamente la mitad de la zona templada de cada continente se ve afectada por al menos un mes de déficit. Bajo un clima con doble CO2, estas áreas se expandirían y cubrirían hasta 77 % de las áreas templadas de América del Norte y hasta 80 % de América del Sur. Los cambios en la distribución de ecosistemas resultantes probablemente serán debidos a la expansión de los desiertos a expensas de los pastizales en América del Norte y del Sur, y la expansión de los pastizales a expensas de los bosques deciduos y boreales en América del Norte. Nuestros análisis asumen que los cambios climáticos futuros estarán abarcados por las predicciones de los tres escenarios de duplicación de CO2 que utilizamos. La situación más probable es que los cambios reales, si es que ocurren, serán distintos a nuestros escenarios. Por lo tanto, nuestros análisis deberán interpretarse como indicaciones de la sensibilidad de partes de las zonas templadas de América del Norte y del Sur a aumentos de temperatura. La principal conclusión de nuestros análisis es que cualquier aumento de temperatura debido a cambios climáticos resultará en una expansión de las porciones más áridas de ambos continentes Abstract in english Under current conditions, large areas of temperate western North America and temperate southern South America have arid to subhumid climates that make them vulnerable to changes as a result of human-induced climate change. Predictions of climate change from global circulation models with a doubling [...] of present atmospheric levels of CO2 suggest large changes in mean annual temperature and small to no changes in mean annual precipitation and the proportion of precipitation received during the summer. Our objective here was to evaluate how predictions of climate change from global circulation models will influence climatic patterns and by inference the distribution of temperate zone ecosystems in North and South America. Calculations of annual water deficits suggest that the area affected by very dry conditions will double as a result of climate change. This expansion will take place in the vicinity of the currently dry areas. Monthly water deficit calculations suggest that approximately half of the temperate zone on each continent is affected by at least one month of deficit. Under a doubled CO2 climate, these areas would expand to cover up to 77 % of the temperate zone of North America and up to 80 % of South America. The resulting changes to the current distribution of ecosystems will likely be an expansion of deserts at the expense of grasslands in North and South America and an expansion of grasslands at the expense of deciduous and boreal forest in North America. Our analyses assumed that future climatic changes will be encompassed by the predictions of our three doubled CO2 scenarios. The most likely situation is that actual changes, if they occur, will be different f

W.K., LAUENROTH; H.E., EPSTEIN; J.M., PARUELO; I.C., BURKE; M.R., AGUIAR; O.E., SALA.

2004-09-01

60

Elemental contents determination in two different zones of Mexico City on the 1987-88 and 1994-95 winters  

International Nuclear Information System (INIS)

During the 1987-1988 and 1994-1995 winters, there were taken samples of aerosols in Mexico City, in two different places, using an integral type of sampler which determines the total amount of suspended particulates; these samples were analyzed by the multi-element analysis technique called PIXE (Proton Induced X-ray Emission). One of the sites corresponds to the Alvaro Obregon area and the other to the Azcapotzalco area (a place near to the18 de Marzo Refinery). There were determined 16 elements, heavy metals, whose concentrations show differences for both sites and periods, standing out for this study the behavior of S, V and Pb. (Author)

 
 
 
 
61

Seasonal dynamics of arboreal spider diversity in a temperate forest.  

Science.gov (United States)

Measuring and estimating biodiversity patterns is a fundamental task of the scientist working to support conservation and inform management decisions. Most biodiversity studies in temperate regions were often carried out over a very short period of time (e.g., a single season) and it is often-at least tacitly-assumed that these short-term findings are representative of long-term general patterns. However, should the studied biodiversity pattern in fact contain significant temporal dynamics, perhaps leading to contradictory conclusions. Here, we studied the seasonal diversity dynamics of arboreal spider communities dwelling in 216 European beeches (Fagus sylvatica L.) to assess the spider community composition in the following seasons: two cold seasons (I: November 2005-January 2006; II: February-April) and two warm seasons (III: May-July; IV: August-October). We show that the usually measured diversity of the warm season community (IV: 58 estimated species) alone did not deliver a reliable image of the overall diversity present in these trees, and therefore, we recommend it should not be used for sampling protocols aimed at providing a full picture of a forest's biodiversity in the temperate zones. In particular, when the additional samplings of other seasons (I, II, III) were included, the estimated species richness nearly doubled (108). Community I possessed the lowest diversity and evenness due to the harsh winter conditions: this community was comprised of one dominant species together with several species low in abundance. Similarity was lowest (38.6%) between seasonal communities I and III, indicating a significant species turnover due to recolonization, so that community III had the highest diversity. Finally, using nonparametric estimators, we found that further sampling in late winter (February-April) is most needed to complete our inventory. Our study clearly demonstrates that seasonal dynamics of communities should be taken into account when studying biodiversity patterns of spiders, and probably forest arthropods in general. PMID:22837825

Hsieh, Yu-Lung; Linsenmair, Karl Eduard

2012-04-01

62

Biological evidence of a winter convection event in the South Adriatic: A phytoplankton maximum in the aphotic zone  

Science.gov (United States)

An unusual phenomenon was recorded in the deep South Adriatic in February 2008: phytoplankton reached their maximum abundance in the aphotic zone. This was associated with strong downward flow induced by (1) surface cooling during bura (the region's cold, dry north wind) events and (2) ingression of more saline Eastern Mediterranean Water. Maximum abundance of microphytoplankton (MICRO) and nanophytoplankton (NANO), 1.4×104 and 6.8×105 cells L-1, respectively, was at 400 m in the South Adriatic Pit. Diatoms dominated deep microphytoplankton samples. Atypically, autotrophic picoflagellates were found throughout the water column, with high abundance in the aphotic layers. Zooplankton did not show such dramatic deviations from their usual vertical distribution, but the abundance and relative contribution of some species between 200 and 800 m layer were markedly different.

Batisti?, Mirna; Jasprica, Nenad; Cari?, Marina; ?ali?, Marijeta; Kova?evi?, Vedrana; Gari?, Rade; Njire, Jakica; Mikuš, Josip; Bobanovi?-?oli?, Svjetlana

2012-08-01

63

Temperature characteristics of winter roost-sites for birds and mammals: tree cavities and anthropogenic alternatives  

Science.gov (United States)

The microclimate of potential roost-sites is likely to be a crucial determinant in the optimal roost-site selection of endotherms, in particular during the winter season of temperate zones. Available roost-sites for birds and mammals in European high trunk orchards are mainly tree cavities, wood stacks and artificial nest boxes. However, little is known about the microclimatic patterns inside cavities and thermal advantages of using these winter roost-sites. Here, we simultaneously investigate the thermal patterns of winter roost-sites in relation to winter ambient temperature and their insulation capacity. While tree cavities and wood stacks strongly buffered the daily cycle of temperature changes, nest boxes showed low buffering capacity. The buffering effect of tree cavities was stronger at extreme ambient temperatures compared to temperatures around zero. Heat sources inside roosts amplified ? T (i.e., the difference between inside and outside temperatures), particularly in the closed roosts of nest boxes and tree cavities, and less in the open wood stacks with stronger circulation of air. Positive ? T due to the installation of a heat source increased in cold ambient temperatures. These results suggest that orchard habitats in winter show a spatiotemporal mosaic of sites providing different thermal benefits varying over time and in relation to ambient temperatures. At cold temperatures tree cavities provide significantly higher thermal benefits than nest boxes or wood stacks. Thus, in winter ecology of hole-using endotherms, the availability of tree cavities may be an important characteristic of winter habitat quality.

Grüebler, Martin U.; Widmer, Silv; Korner-Nievergelt, Fränzi; Naef-Daenzer, Beat

2014-07-01

64

The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone  

Science.gov (United States)

Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas (GHG) flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a 2-year study of the net ecosystem carbon balance (NECB) of two such sites. We determined GHG fluxes and waterborne carbon (C) emissions in a nutrient-rich grassland and compared it with values measured from two nutrient-poor organic soils: a deep-drained and a shallow-drained site. Carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) fluxes were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient-rich site was an annual source of CO2 (233 g C m-2 yr-1), CH4 neutral, and a small source of N2O (0.16 g N2O-N m-2 yr-1). Net ecosystem exchange (NEE) at the shallow-drained nutrient-poor site was -89 and -99 g C m-2 yr-1 in Years 1 and 2 respectively, and NEE at the deep-drained nutrient-poor site was 85 and -26 g C m-2 yr-1 respectively. Low CH4 emissions (1.3 g C m-2 yr-1) were recorded at the shallow-drained nutrient-poor site. Fluvial exports from the nutrient-rich site totalled 69.8 g C m-2 yr-1 with 54% as dissolved organic C. Waterborne C losses from the nutrient-poor site reflected differences in annual runoff totalling 44 g C m-2 yr-1 in Year 1 and 30.8 g C m-2 yr-1 in Year 2. The NECB of the nutrient-rich grassland was 663 g C m-2 yr-1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient-poor deep-drained site was less than half of the nutrient-rich site (2-year mean 267 g C m-2 yr-1). Although NEE at the nutrient-poor shallow-drained site was negative in both years, high biomass export meant it was a net C source (2-year mean NECB 103 g C m-2 yr-1). While the impacts of the nutrient and drainage status on NEE, biomass exports and fluvial C losses were confirmed, inter-regional differences in management practice and climate were also significant factors which impacted on the overall NECB of these ecosystems. Contrary to expectation, the NECB of nutrient-poor drained organic soils under grasslands is not necessarily a large C source and this has implications for Ireland's choice of national GHG inventory reporting methodologies. This study can also aid the development of strategies to deliver reduced emissions tailored to local grassland types.

Renou-Wilson, F.; Barry, C.; Müller, C.; Wilson, D.

2014-08-01

65

The impacts of drainage, nutrient status and management practice on the full carbon balance of grasslands on organic soils in a maritime temperate zone  

Directory of Open Access Journals (Sweden)

Full Text Available Temperate grasslands on organic soils are diverse due to edaphic properties but also to regional management practices and this heterogeneity is reflected in the wide range of greenhouse gas flux values reported in the literature. In Ireland, most grasslands on organic soils were drained several decades ago and are managed as extensive pastures with little or no fertilisation. This study describes a two-year study of the net ecosystem carbon balance (NECB of two such sites. We determined greenhouse gas (GHG fluxes and waterborne carbon emissions in a nutrient rich grassland and compared it with values measured from two nutrient poor organic soils: a deep drained and a shallow drained site. GHG fluxes (CO2, CH4 and N2O were determined using the chamber technique, and fluvial C fluxes were estimated by combining drainage water concentrations and flows. The nutrient rich site was an annual source of CO2 (NEE 233 g C m?2yr?1, CH4 neutral, and a small source of nitrous oxide (1.6 kg N2O-N ha?1yr?1. NEE at the shallow drained site was ?89 and ?99 g C m?2yr?1 in Years 1 and 2 respectively, and NEE at the deep drained site was +85 and ?26 g C m?2yr?1 respectively. Low CH4 emissions (1.3 g C m?2yr?1 were recorded at the shallow drained nutrient poor site. Fluvial exports from the nutrient rich site totalled 69.8 g C m?2yr?1 with 54% as dissolved organic C (DOC. Waterborne C losses from the nutrient poor site reflected differences in annual runoff totalling 44 g C m?2yr?1 in Year 1 and 30.8 g C m?2yr?1 in Year 2. The NECB of the nutrient rich grassland was 663 g C m?2yr?1 with biomass exports being the major component accounting for 53%. The NECB of the nutrient poor deep drained site was less than half of the nutrient rich site (2 year mean 267 g C m?2yr?1. Although NEE at the nutrient poor shallow drained site was negative in both years, high biomass export meant it was a net C source (2 year mean NECB 103 g C m?2yr?1. While the impacts of the nutrient and drainage status on NEE, biomass exports and fluvial C losses were confirmed, inter-regional differences in management practice and climate are also significant factors which impact on the overall NECB of these ecosystems. Contrary to expectation, the NECB of nutrient poor drained organic soils under grasslands is not necessarily a large C source and this has implications for Ireland's choice of national GHG inventory reporting methodologies. This study can also aid the development of strategies to deliver reduced emissions tailored to local grassland types.

F. Renou-Wilson

2014-04-01

66

Microstructure of tempered AISI 403 stainless steel  

Energy Technology Data Exchange (ETDEWEB)

The microstructure of AISI 403 martensitic stainless steel (AISI 403 MSS) tempered at various temperatures for various times was investigated by transmission electron microscopy (TEM). The microstructure consisted of tempered martensite laths together with carbides and a small amount of [delta]-ferrite. At lower tempering temperatures of 480 and 540 C, two types of carbides, Cr[sub 23]C[sub 6] and Cr[sub 7]C[sub 3], were present. The majority of the Cr[sub 23]C[sub 6] carbides were in the martensitic matrix and a chain of Cr[sub 23]C[sub 6] carbide was seen at and in the vicinity of grain boundaries. Upon tempering at 600 or 660 C, Cr[sub 23]C[sub 6] became the predominant carbide and was mainly distributed at the boundaries of the martensitic laths. The results showed that secondary hardening in AISI 403 MSS, produced by tempering at lower temperatures, especially 480 C, resulted from Cr[sub 23]C[sub 6] carbides heterogeneously precipitated in the martensitic matrix. For specimens tempered at 600 C and above, severe sensitization and loss of corrosion resistance of the steel occurred owing to large Cr[sub 23]C[sub 6] precipitates which were concentrated at the grain boundaries, forming a zone of reduced chromium content adjacent to the carbides in the grain boundaries. (orig.)

Miao Baihe (Dept. of Mechanical Engineering, Univ. of Windsor, Ontario, ON (Canada)); Northwood, D.O. (Dept. of Mechanical Engineering, Univ. of Windsor, Ontario, ON (Canada)); Lim, L.C. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (Singapore)); Lai, M.O. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (Singapore))

1993-11-01

67

Climate warming will not decrease winter mortality  

Science.gov (United States)

It is widely assumed by policymakers and health professionals that the harmful health impacts of anthropogenic climate change will be partially offset by a decline in excess winter deaths (EWDs) in temperate countries, as winters warm. Recent UK government reports state that winter warming will decrease EWDs. Over the past few decades, however, the UK and other temperate countries have simultaneously experienced better housing, improved health care, higher incomes and greater awareness of the risks of cold. The link between winter temperatures and EWDs may therefore no longer be as strong as before. Here we report on the key drivers that underlie year-to-year variations in EWDs. We found that the association of year-to-year variation in EWDs with the number of cold days in winter ( health adaptation policies.

Staddon, Philip L.; Montgomery, Hugh E.; Depledge, Michael H.

2014-03-01

68

Off-season uptake of nitrogen in temperate heath vegetation.  

Science.gov (United States)

In this field study we show that temperate coastal heath vegetation has a significant off-season uptake potential for nitrogen, both in the form of ammonium and as glycine, throughout winter. We injected 15N-ammonium and 15N 2x(13C)-glycine into the soil twice during winter and once at spring. The winter temperatures were similar to those of an average winter in the northern temperate region of Europe, with only few days of soil temperatures below zero or above 5 degrees C. The vegetation, consisting of the evergreen dwarf shrub Calluna vulgaris, the deciduous dwarf shrub Salix arenaria, and the graminoids Carex arenaria and Deschampsia flexuosa, showed high root uptake of both forms of nitrogen, both 1 day after labelling and after a month, in species specific temporal patterns. Plant uptake of 13C was not significant, providing no further evidence of intact uptake of glycine. Translocation of the labelled nitrogen to shoots was generally evident after 1 month and increased as spring approached, with different translocation strategies in the three plant functional types. Furthermore, only the graminoids showed shoot growth during winter. Increasing plant nitrogen concentration from fall to spring at temperate heaths may, hence, be due to nitrogen uptake. Our results suggest that the potential for nitrogen uptake in plants at winter is of the same order of magnitude as at summer. Hence, winter nitrogen uptake in ecosystems in the temperate/boreal region should be considered when making annual nitrogen budgets of heath ecosystems, and the view of plant nutrient uptake as low in this climatic region during winter should be revised. PMID:15868162

Andresen, Louise C; Michelsen, Anders

2005-08-01

69

Hot wire TIG temper bead welding for nuclear repairs  

International Nuclear Information System (INIS)

A preliminary assessment has been carried out to determine the suitability of the hot wire tungsten inert gas (TIG) welding process for the repair of thick section, ferritic steel nuclear pressure vessels. The objective has been to identify a hot wire TIG temper bead procedure, suitable for repairs without post weld heat treatment. This procedure involves depositing two weld layers with carefully selected welding parameters such that overlapping thermal cycles produce a refined and tempered heat affected zone, HAZ, microstructure. (author)

70

Alcohol, Temperance & Prohibition  

Science.gov (United States)

The temperance movement in the United States gained steam in the late 19th century, and by the early 20th century, many political candidates would be asked "Are you 'dry' or 'wet?'" This single issue led to the creation of the 18th Amendment in 1919, which effectively prohibited the manufacturing, sale or transportation of intoxicating liquors. After fourteen years, the 21st Amendment was passed, and the country went back to imbibing beer and spirits (legally, anyway). This fine collection from the Brown University Library Center for Digital Scholarship brings together over 1,600 pieces of ephemera, such as broadsides and pamphlets, that document the quest to make prohibition a reality during this period in American history. First-time visitors may wish to start by reading the narrative essay titled "Temperance and Prohibition Era Propaganda: A Study in Rhetoric." Moving on, visitors can browse and search their way through this remarkable collection. Items of note include a 1913 informational handout titled "Abstainers have less sickness" and the 1928 Women's Christian Temperance Union publication "American Youth Under Prohibition."

2012-06-01

71

Off-season uptake of nitrogen in temperate heath vegetation  

DEFF Research Database (Denmark)

Off-season ecosystem processes is becoming an area of increasing interest, being important when considering annual nitrogen and carbon budgets. The general assumption that physiological activity in soil microorganisms as well as vegetation is low during winter may not be justified. In this field study we show that northern temperate coastal heath vegetation has a significant uptake potential for nitrogen, both in the form of ammonium and as glycine, throughout the non-growing season. We used 15N ammonium and 2*(13C)15N glycine as nutrient tracer. This was injected into the soil two times during winter and once at spring. The winter temperatures were similar to those of average winter in the northern temperate region of Europe, with only few days of soil temperatures below zero and a winter mean of 2.4 °C. The vegetation, consisting of the evergreen dwarf shrub Calluna vulgaris (L.), the deciduous dwarf shrub Salix arenaria (L.) and the graminoids Carex arenaria (L.) and Deschampsia flexuosa (L.), showed root uptake of both forms of nitrogen, both one day after labelling and after a month. Translocation of the labelled nitrogen to shoots was generally evident after one month and increased as spring approached, with different translocation strategies in the three plant functional types. Furthermore, shoot total nitrogen concentration increased in all plant types, but only the graminoids and, eventually, S. arenaria showed shoot growth during winter. Our study suggests that plant nitrogen uptake can cause increasing nitrogen concentration in shoot tissue from fall to spring. To our knowledge this is one of the first studies of plant nitrogen uptake during nongrowing season at a temperate heath. Our results show that the nitrogen uptake is in the same order of magnitude as summer uptake in other types of ecosystems in the temperate/boreal region. These results suggest that plant nitrogen uptake during winter should be included in the annual nitrogen budgets of heath ecosystems, and that the view of plant nutrient uptake as low in this climatic region during winter should be revised. Furthermore, these results should be taken into account when ecosystem responses to climatic changes such as warming are evaluated.

Andresen, Louise Christoffersen; Michelsen, Anders

2004-01-01

72

Nuclear Winter Revisited  

Science.gov (United States)

A “major nuclear exchange” between the United States and the Soviet Union could inject enough smoke and dust into the atmosphere to cause significant temperature drops over the northern temperate zone that could last from weeks to months, according to a new study by the National Research Council (NRC).The results of the NRC study are “consistent with the results that came out of the TTAPS study” released late in 1983, according to George Carrier, chairman of the NRC study committee. The TTAPS study—named for authors R. P. Turco, O. B. Toon, T. P. Ackerman, J. B. Pollack, and Carl Sagan—investigated the potential global atmospheric and climatic consequences of nuclear war.

Robb, David W.

73

Carbon sinks in temperate forests  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In addition to being scientifically exciting, commercially important, and environmentally essential, temperate forests have also become a key diplomatic item in international climate negotiations as potential sinks for carbon. This review presents the methods used to estimate carbon sequestration, identifies the constraints and opportunities for carbon sequestration in temperate forests, addresses the issues raised by the monitoring of carbon sequestration, and analyzes uncertainties pertaini...

Martin, P. H.; Nabuurs, G. J.; Aubinet, M.; Karjalainen, T.; Vine, E. L.; Kinsman, J.; Heath, L. S.

2001-01-01

74

Considerations about tempered martensite embrittlement  

International Nuclear Information System (INIS)

There have been many quite meritorious studies made about the present subject. However, there are still some open questions: whether the mechanism of plastic deformation is the same in the Charpy test and in the slow static test, and what is the effect of the rate of work-hardening. The material selected for the tests was a common Cr-Mo steel. The long time tempering was carried out in a salt bath. A welding simulator was applied for the very short tempering. The stress-strain curves at some interesting tempering temperatures were determined by torsion tests. The Charpy impact tests were accomplished using V and U shaped specimens. The deformation and fracture of the specimen were studied with optical and scanning electron microscopes. There was no tempered martensite embrittlement in the specimens in the very short tempering time. (orig.)

75

Winter Storm  

Science.gov (United States)

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the ...

Schilling, Ashley

2010-05-26

76

Late Quaternary environmental change along the temperate-tropical interface in southern Africa. (Invited)  

Science.gov (United States)

As a relatively low-relief landscape stretching from the equator to the mid-latitudes, the African sector of the Southern Hemisphere provides an excellent opportunity to study long-term interactions between tropical, subtropical and temperate climate systems. This potential, however, has remained largely unrealised as funding has generally been focussed on the large lakes of Eastern Africa and the analysis of marine cores from the continental margin. The result is a spatially and temporally disjunct regional dataset, and the dominance of broad conceptual models to contextualise the limited available data and explain palaeoenvironmental dynamics. The dominant hypotheses to explain long-term climate change in southern Africa are: 1) changes in temperate systems result from expansions and contractions of Antarctic sea-ice that vary with trends in polar/global temperatures; 2) tropical change is primarily a function of shifts in the mean position of the Intertropical Convergence Zone (ITCZ) as a result of orbitally-induced changes in direct insolation forcing, and/or as a response to Northern Hemisphere cooling. In both cases, some evidence exists to support these hypotheses, but the proxies and interpretations are not unambiguous, and in some cases the interpretations of the data have been primarily developed to conform to the dominant conceptual paradigm. This paper will discuss the interplay between temperate and tropical systems in southern Africa, and the implications for hemispheric and global climate dynamics. New data, particularly high-resolution records from fossilised rock hyrax middens (Chase et al., 2012, Quaternary Science Reviews; www.hyrax.univ-montp2.fr), is providing a robust framework into which lower resolution or more poorly understood proxies can better understood. Findings from a subcontinental-scale initiative funded by the European Research Council so far indicate that shifts of the Subtropical Front and the westerly storm tracks did bring increased moisture to SW Africa during phases of the last glacial period, and that the so-called winter rainfall zone (sensu Chase and Meadows, 2007, Earth-Science Reviews) extended at least as far north as central Namibia. It cannot, however, be said that all cold periods resulted in increased westerly influence in the region, as changes in the position and intensity of the South Atlantic Anticyclone have at times modified their impact. New evidence also clearly indicates that shifts in the mean position of the ITCZ, either as a result of direct insolation forcing or Northern Hemisphere cooling, did not determine patterns of long-term climate change in southern Africa, and that both the northern and southern tropics experienced synchronous patterns of climate change since the Last Glacial Maximum (Chase et al., 2009, Geology; Truc et al., 2013, Palaeogeography, Palaeoclimatology, Palaeoecology).

Chase, B. M.

2013-12-01

77

Transfer parameter values in temperate forest ecosystems: a review  

Energy Technology Data Exchange (ETDEWEB)

Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (T{sub ag} in m{sup 2} kg{sup -1}) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean T{sub ag} values was 10{sup -3} m{sup 2} kg{sup -1} (dry weight). Tree foliage was usually 2-12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of T{sub ag}, from 10{sup -3} to 10{sup 1} m{sup 2} kg{sup -1} (dry weight). For berries, typical values are around 0.01-0.1 m{sup 2} kg{sup -1} (dry weight). Transfer of radioactive caesium to game animals and reindeer and the rate of activity reduction, quantified as an ecological half-life, reflect the soil and pasture conditions at individual locations. Forests in temperate and boreal regions differ with respect to soil type and vegetation, and a faster decline of muscle activity concentrations in deer occurs in the temperate zone. However, in wild boar the caesium activity concentration shows no decline because of its special feeding habits. In the late phase, i.e. at least a few months since the external radionuclide contamination on feed plants has been removed, a T{sub ag} value of 0.01 m{sup 2} kg{sup -1} (fresh weight) is common for {sup 137}Cs in the muscles of adult moose and terrestrial birds living in boreal forests, and 0.03 m{sup 2} kg{sup -1} (fresh weight) for arctic hare. Radiocaesium concentrations in reindeer muscle in winter may exceed the summer content by a factor of more than two, the mean T{sub ag} values for winter ranging from 0.02 to 0.8 m{sup 2} kg{sup -1} (fresh weight), and in summer from 0.04 to 0.4 m{sup 2} kg{sup -1}. The highest values are found in the year of initial contamination, followed by a gradual reduction. In waterfowl a relatively fast decline in uptake of {sup 137}Cs has been found, with T{sub ag} values changing from 0.01 to 0.002 m{sup 2} kg{sup -1} (fresh weight) in the three years after the contaminating event, the rate being determined by the dynamics of {sup 137}Cs in aquatic ecosystems.

Calmon, Philippe [Department of Radioecology, Institute of Radioprotection and Nuclear Safety, CE Cadarache, BP 3, 13115 Saint Paul-les-Durance Cedex (France)], E-mail: philippe.calmon@irsn.fr; Thiry, Yves [Biosphere Impact Studies, Belgian Nuclear Research Center (SCK.CEN, Foundation of Public Utility), 2400 Mol (Belgium); Zibold, Gregor [Hochschule Ravensburg-Weingarten, University of Applied Sciences, 88250 Weingarten (Germany); Rantavaara, Aino [Research and Environmental Surveillance, Radiation and Nuclear Safety Authority (STUK), BP 14, FIN-00881 Helsinki (Finland); Fesenko, Sergei [International Atomic Energy Agency (IAEA), 1400 Vienna (Austria)

2009-09-15

78

Spatial variation of biomass of seaweed assemblages in the temperate-tropical transition zone of Baja California Peninsula, Mexico / Variación espacial de la biomasa de macroalgas en una zona de transición templado-tropical en la Península de Baja California, México  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Se analizaron los cambios en la biomasa de las asociaciones de macroalgas en una zona de transición templado-tropical entre octubre de 1996 y agosto de 1997 en cuatro localidades. Las localidades con la temperatura más baja, alto índice de surgencias y mayor dominancia de sustrato duro presentaron l [...] os mayores valores de biomasa de macroalgas (El Cardoncito (7.2 kg m-2) y Las Boyitas (6.2 kg m-2)) y la mayor cantidad de especies de afinidad templada. Por el contrario El Datilito (0.366 kg m-2) en donde la temperatura fue más alta, no hay evidencia de surgencias, el sustrato es arenoso, es un área más somera y protegida, presentó el menor valor de biomasa de macroalgas y la menor proporción de algas de afinidad templada. Los análisis de componentes principales y similaridad mostraron una estrecha relación entre El Cardoncito y Las Boyitas. El Datilito se mantuvo como una localidad independiente, mientras que Chester Rock (4.3 kg m-2) tuvo características intermedias de biomasa de algas. La estrecha relación entre las dos primeras localidades puede explicarse por la similaridad en términos de su alta biomasa aunado con las características fisiográficas y ambientales que presentaron. El Datilito presentó características fisiográficas y ambientales muy diferentes a las demás localidades, además de tener muy poca biomasa de macroalgas. Abstract in english Biomass changes of seaweed assemblages in four locations in a temperate-tropical transition zone were analyzed between October 1996 and August 1997. Locations with lower temperature, a high index of upwelling, and high quantities of hard substrate presented the largest values of biomass of seaweed ( [...] El Cardoncito (7.2 kg m-2), and Las Boyitas (6.2 kg m-2)) and the biggest quantity of species of temperate affinity. Conversely, El Datilito (0.366 kg m-2), with a higher temperature, no evidence of upwelling, sandy substrate, and located in protected shallow waters, presented the lowest values of biomass and the lowest proportion of temperate affinity seaweed. The PCA and similarity analysis showed a close relationship between El Cardoncito and Las Boyitas. El Datilito was categorized as independent location, while Chester Rock (4.3 kg m-2) displayed intermediate characteristics. The close relationship observed between the first two locations can be explained by the similarity of their high biomass and physiographic and environmental characteristics. El Datilito has very different physiographic and environmental characteristics and a very low biomass.

Margarita, Casas Valdez; Ruth Noemí, Aguila Ramírez.

2008-08-01

79

Solar ventilation and tempering  

Science.gov (United States)

The paper presents basic information about solar panels, designed, realized and used for solar ventilation of rooms. Used method of numerical flow simulation gives good overview about warming and flowing of the air in several kinds of realized panels (window, facade, chimney). Yearlong measurements give a good base for calculations of economic return of invested capital. The operation of the system in transient period (spring, autumn) prolongs the period without classical heating of the room or building, in winter the classical heating is supported. In the summer period the system, furnished with chimney, can exhaust inner warm air together with necessary cooling of the system by gravity circulation, only. System needs not any invoiced energy source; it is supplied entirely by solar energy. Large building systems are supported by classical electric fan respectively.

Adámek, Karel; Pavlů, Miloš; Bandouch, Milan

2014-08-01

80

Time-temperature equivalence in Martensite tempering  

Energy Technology Data Exchange (ETDEWEB)

The relationship between time and temperature is of great consequence in many materials-related processes including the tempering of martensite. In 1945, Hollomon and Jaffe quantified the 'degree of tempering' as a function of both tempering time, t, and tempering temperature, T, using the expression, T(log t + c). Here, c is thought to be a material constant and appears to decrease linearly with increasing carbon content. The Hollomon-Jaffe tempering parameter is frequently cited in the literature. This work reviews the original derivation of the tempering parameter concept, and presents the use of the characteristics diffusion distance as an alternative time-temperature relationship during martensite tempering. During the tempering of martensite, interstitial carbon atoms diffuse to form carbides. In addition, austenite decomposes, dislocations and grain boundaries rearrange, associated with iron self diffusion. Since these are all diffusional processes, it is reasonable to expect the degree of tempering to relate to the extent of diffusion.

Hachenberg, Robert, E. [Los Alamos National Laboratory; Thomas, Grant, A. [CSM; Speer, John, G. [CSM; Matlock, David, K. [CSM; Krauss, George [CSM

2008-01-01

 
 
 
 
81

Internal strains after recovery of hardness in tempered martensitic steels for fusion reactors  

International Nuclear Information System (INIS)

After tempering, with recovery of hardness, MANET steels present internal strains; these residual strains increase with quenching rate prior to tempering, and they remain after prolonged tempering times. On account of their persistence, after thermal treatments which lead to low dislocation and sub-boundary densities, the possibility has been considered that the high swelling resistance of MANET is connected with these centres of strain, probably connected with the formation, in ferrite, of Cr-enriched and contiguous Cr-depleted zones which may act as sinks for interstitials. Comparative observations on the internal strain behaviour of cold worked 316 L stainless steel appear consistent with this possibility. (orig.)

82

Tempering effect on the properties of welded joints of 15Kh2NMFA  

Energy Technology Data Exchange (ETDEWEB)

A study was made on the effect of post welding tempering on mechanical properties of the basic metal, weld and heat affected zone, their resistance to softening during the following technological heatings and to brittle failure, as well as on phase composition and the state of basic phase components of 15Kh2NMFA steel. It was shown that the optimal combination of strength and resistance to embrittlement of the basic metal and weld is reached at tempering temperature of 650 deg C.

Sandomirskij, M.M.; Kovalev, V.A.; Stepanov, E.Z.

1982-10-01

83

Tempering effect on the properties of welded joints of 15Kh2NMFA  

International Nuclear Information System (INIS)

A study was made on the effect of post welding tempering on mechanical properties of the basic metal, weld and heat affected zone, their resistance to softening during the following technological heatings and to brittle failure, as well as on phase composition and the state of basic phase components of 15Kh2NMFA steel. It was shown that the optimal combination of strength and resistance to embrittlement of the basic metal and weld is reached at tempering temperature of 650 deg C

84

Diversity and abundance of photosynthetic sponges in temperate Western Australia  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Photosynthetic sponges are important components of reef ecosystems around the world, but are poorly understood. It is often assumed that temperate regions have low diversity and abundance of photosynthetic sponges, but to date no studies have investigated this question. The aim of this study was to compare the percentages of photosynthetic sponges in temperate Western Australia (WA with previously published data on tropical regions, and to determine the abundance and diversity of these associations in a range of temperate environments. Results We sampled sponges on 5 m belt transects to determine the percentage of photosynthetic sponges and identified at least one representative of each group of symbionts using 16S rDNA sequencing together with microscopy techniques. Our results demonstrate that photosynthetic sponges are abundant in temperate WA, with an average of 63% of sponge individuals hosting high levels of photosynthetic symbionts and 11% with low to medium levels. These percentages of photosynthetic sponges are comparable to those found on tropical reefs and may have important implications for ecosystem function on temperate reefs in other areas of the world. A diverse range of symbionts sometimes occurred within a small geographic area, including the three "big" cyanobacterial clades, Oscillatoria spongeliae, "Candidatus Synechococcus spongiarum" and Synechocystis species, and it appears that these clades all occur in a wide range of sponges. Additionally, spongin-permeating red algae occurred in at least 7 sponge species. This study provides the first investigation of the molecular phylogeny of rhodophyte symbionts in sponges. Conclusion Photosynthetic sponges are abundant and diverse in temperate WA, with comparable percentages of photosynthetic to non-photosynthetic sponges to tropical zones. It appears that there are three common generalist clades of cyanobacterial symbionts of sponges which occur in a wide range of sponges in a wide range of environmental conditions.

Brümmer Franz

2009-02-01

85

Responses of plankton and fish from temperate zones to UVR and temperature in a context of global change / Respuestas del plancton y peces de zonas templadas a la RUV y la temperatura en un contexto de cambio global  

Scientific Electronic Library Online (English)

Full Text Available SciELO Argentina | Language: English Abstract in spanish En las últimas décadas, tanto la temperatura como la radiación UVB (280-315 nm) en la superficie del planeta han aumentado a velocidades crecientes como resultado de las actividades humanas. Muchos estudios han evaluado ya los efectos de la temperatura en ecosistemas acuáticos, pero ahora el campo d [...] e estudio se amplía a medida que cobra importancia la combinación de dichos factores. En el presente estudio, intentamos rever una parte de lo que sabemos acerca de los efectos de la RUV y la temperatura en el plancton marino y dulceacuícola y peces de latitudes medias (definidas como aquellas comprendidas entre 30 y 60º), especialmente en la región Patagónica, debido a las características particulares de estas regiones. La RUV afecta (en general, negativamente) casi todos los procesos, desde la fijación de carbono hasta el comportamiento y ciertamente todos los niveles tróficos dentro del plancton, desde virus hasta larvas de peces. El mayor efecto negativo de la RUV es probablemente la acción mutagénica de la UVB, la cual afecta un número de procesos tales como fotosíntesis, crecimiento y división celular, entre muchos otros. En los metazoos, la RUV puede ser un factor de estrés que afecta la supervivencia, o bien puede mostrar efectos subletales tales como en el comportamiento y alimentación. Es difícil extraer un patrón general en cuanto a las respuestas, aun dentro de un grupo de organismos, ya que éstas son generalmente especie-específicas y están fuertemente influenciadas por condiciones locales (e.g., penetración de la RUV, relación PAR/RUV y aclimatación). A pesar de que en muchos casos se han determinado efectos significativos, muchos organismos también disponen de mecanismos para evitar o minimizar el daño producido por la RUV. Sin embargo, este puede no ser el caso si consideramos los cambios en la temperatura. En peces por ejemplo, la temperatura es probablemente el factor más importante que determina la distribución del hábitat, y por lo tanto la biogeografía debe ser considerada para considerar las posibles consecuencias de los cambios de temperatura y de la RUV. Aun en los diferentes escenarios predichos por los modelos climáticos (incluyendo la recuperación de la capa de ozono y el aumento de la temperatura durante las próximas décadas) serán necesarias más investigaciones combinando RUV y temperatura para entender las respuestas de los ecosistemas acuáticos en el contexto del cambio global. Abstract in english In the last decades, both temperature and UVB (280-315 nm) radiation on the surface of the Earth increased at growing rates as a result of human activities. Many studies had evaluated the effects of temperature on aquatic ecosystems, but now the field broadens as the combination and variations of te [...] mperature and radiation gains especial importance. In this work we attempt to revisit some of our knowledge about the effects of UVR and temperature on marine and freshwater plankton and fish from temperate regions (defined here as latitudes between 30-60º), especially from the Patagonia area, due to the special characteristics found in these sites. UVR affects (often negatively) almost all processes, from carbon fixation to behavior; and certainly all trophic levels in plankton, from virus to fish larvae. The most prominent UVR danger is probably the mutagenic action of UVB, which will affect a number of processes such as photosynthesis, growth and cell division, among many others. In metazoans, UVR may cause stress upon survival or show sublethal effects such as those in behavior and feeding. It is difficult to extract a general pattern, even in a group of organisms, as responses to UVR appear to be species-specific and strongly influenced by local conditions (e.g., UVR penetration, PAR/UVR ratios, and acclimation). While in many cases significant effects have been determined, a number of mechanisms are available to avoid and / or minimize the damage produced by UVR. However,

Rodrigo J, Gonçalves; María Sol, Souza; Juana, Aigo; Beatriz, Modenutti; Esteban, Balseiro; Virginia E, Villafañe; Víctor, Cussac; E Walter, Helbling.

2010-08-01

86

Intraspecific Variation in Leaf Life Span for the Semi-evergreen Liana Akebia trifoliata is Caused by Both Seasonal and Aseasonal Factors in a Temperate Forest  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperateforest in Japan. Akebia is semi-evergreen: some leaves are shed before winter, while others remain through thewinter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variationin the timing of leaf emergence. Leaves that appeared just before winter over-wintered, while leaves appearingearlier were shed. However, it is unclear whether leaves of the sam...

Koyama, Kohei; Kihachiro Kikuzawa

2008-01-01

87

Transformation and tempering behavior of 12Cr-1Mo-0.3V martensitic stainless steel weldments  

International Nuclear Information System (INIS)

Autogeneous, bead-on-plate gas tungsten-arc (GTA) and laser welds in a 12Cr-1Mo-0.3V (HT9) martensitic stainless steel were evaluated using both optical metallography and microhardness techniques. The as-welded fusion zone microstructures consisted of a mixture of untempered martensite and metastable delta ferrite and exhibited a hardness in the range of Rsub(c) 48-55. Four distinct microstructural regions were identified in the heat-affected zone (HAZ) of the GTA welds and could be related to specific phase regions on the equilibrium phase diagram. The tempering behavior of the GTA and laser welds was similar. The tempering response was relatively sluggish at temperatures below 6000C (11100F). Tempering for 1 hour at 8000C (14700F) reduced the hardness of both the fusion zone and HAZ to the level of the quenched and tempered base metal. (orig.)

88

Chilling and heat requirements for flowering in temperate fruit trees.  

Science.gov (United States)

Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut (Castanea mollissima Blume) and jujube (Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing’s cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics. PMID:23958788

Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

2014-08-01

89

Chilling and heat requirements for flowering in temperate fruit trees  

Science.gov (United States)

Climate change has affected the rates of chilling and heat accumulation, which are vital for flowering and production, in temperate fruit trees, but few studies have been conducted in the cold-winter climates of East Asia. To evaluate tree responses to variation in chill and heat accumulation rates, partial least squares regression was used to correlate first flowering dates of chestnut ( Castanea mollissima Blume) and jujube ( Zizyphus jujube Mill.) in Beijing, China, with daily chill and heat accumulation between 1963 and 2008. The Dynamic Model and the Growing Degree Hour Model were used to convert daily records of minimum and maximum temperature into horticulturally meaningful metrics. Regression analyses identified the chilling and forcing periods for chestnut and jujube. The forcing periods started when half the chilling requirements were fulfilled. Over the past 50 years, heat accumulation during tree dormancy increased significantly, while chill accumulation remained relatively stable for both species. Heat accumulation was the main driver of bloom timing, with effects of variation in chill accumulation negligible in Beijing's cold-winter climate. It does not seem likely that reductions in chill will have a major effect on the studied species in Beijing in the near future. Such problems are much more likely for trees grown in locations that are substantially warmer than their native habitats, such as temperate species in the subtropics and tropics.

Guo, Liang; Dai, Junhu; Ranjitkar, Sailesh; Yu, Haiying; Xu, Jianchu; Luedeling, Eike

2014-08-01

90

Protective coating of austenitic steel using robotized GMAW temper-bead technique; Rechargement d'inox austenitique en MAG temperbead robotise  

Energy Technology Data Exchange (ETDEWEB)

This paper summarises experimental results obtained in a study of GMAW temper-bead on low alloyed steel with austenitic consumables. Temper-bead on low alloyed steel with austenitic consumables is mainly used for repairing operations of heavy components such as vessel reactor of nuclear power plants. Experimental work aims at showing the performance of GMAW compared to GTAW and the consequences of GMAW temper-bead on 2OMND5 heat affected zones. (authors)

Carpreau, J.M. [Electricite de France (EDF/R and D), Recherche et Developpement, 92 - Chatou (France); Dainelli, P. [Institut de Soudure, 57 - Yutz (France)

2009-07-15

91

Mechanical properties and residual stresses in temper bead welded specimens  

Energy Technology Data Exchange (ETDEWEB)

Welding is the principal joining technology used in the fabrication of metallic structures. One of the alternative techniques for post-welded heat treatment(PWHT) is bead tempering during the welding process, where this technique is usually called temper bead welding(TBW). Welding of mild steels and low alloy ferritic steels often requires stress relieving by using PWHT. These heat treatments can be carried out easily during initial fabrication processes. However, PWHT is almost impossible when there are mechanical loads on the structure since it can cause deformation of the structure. In actual effect, the HAZ created by former of three successive beads is tempered by controlling the heat input ratio between three beads(which may also form three weld layers). Also, in recent years considerable effort has been devoted to the development of procedures for incorporating residual stresses in to structural integrity assessments for power plant infrastructure. However, systematic understandings of microstructural changes and mechanical properties as a result of varying in welding sequences and the resulting properties have not been established. The paper particularly investigates the role of the deposition sequence and the spatial deposition of the welding beads in microstructural variation in the critical zones of the resulting weldments such as HAZ, characterising the metallurgical properties, residual stresses, micro hardnesses of such zones.

Kim, Kyeong Ho; Kim, Hong Eun; Lee, Ho Jin; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2009-05-15

92

Citril finches during the winter: patterns of distribution, the role of pines and implications for the conservation of the species.  

Directory of Open Access Journals (Sweden)

Full Text Available The Citril finch Serinus citrinella is a Paleartic endemic species that breeds in the subalpine mountain zones of western temperate Europe. The species seems to be suffering a serious decline in its northern range, mainly in the Black Forest and the NE of the Alps. Numerous reasons have been provided for this decline, but all of them have been related to breeding habitats. Given that the species undergoes an altitu¬dinal migration and that during winter it may use very different habitats, a sound knowledge of the distribution patterns and habitats used outside the breeding period is needed to conduct adequate conservation policies and management. This information, however, is largely lacking. The aim of this paper was to determine the current habitat used by Citril finches in north–eastern Spain during the winter, to analyse habitat suitability and to study movements, by investigating the origin of birds that overwinter in Catalonia. Citril finch distribution was modelled using both discriminant analysis and maximum entropy modelling, on the basis of species occurrences during winter in Catalonia (data from 1972–2009. Results showed that the presence of two tree species, Black pine (Pinus nigra subsp. salzmanii and Scots pine (Pinus sylvestris, both as part of mixed open forests, and the presence of abundant farmland and arvensic plants —the two vegetation units located in a typical sub¬mediterranean context, where the warm temperatures (sunny days in late winter permit the cones to open—, were the ecological and bioclimatic variables that explain the distribution model. All these variables in tandem seem to be the key for the current potential distribution of the Citril finch in winter (AUCscores: training data AUC= 0.955; test data AUC = 0.953. We analyzed recoveries (N = 238 of 2,368birds ringed at wintering grounds and 12,648 birds ringed at subalpine localities in the adjacent Pyrenees from 1977–2004. We found that in the study area, we recovered ringed birds from many different locations from across the distributional range of the species, including trans–Pyrenean birds from the Alps. This stresses the high mobility of Citril finch populations to reach wintering areas. From a conservation point of view, the high importance of pines (mainly Black pine for the wintering distribution of the species stresses that any threat on pines, especially forest fires, will have acute detrimental effects for Citril finch populations.

X. Colomé

2010-01-01

93

The well-tempered neutralino  

Energy Technology Data Exchange (ETDEWEB)

The dark-matter prediction is usually considered as one of the successes of low-energy supersymmetry. We argue that, after LEP constraints are taken into account, the correct prediction for the dark-matter density, at a quantitative level, is no longer a natural consequence of supersymmetry, but it requires special relations among parameters, highly sensitive to small variations. This is analogous to the problem of electroweak-symmetry breaking, where the correct value of the Z mass is obtained only with a certain degree of fine tuning. In the general parameter space of low-energy supersymmetry, one of the most plausible solution to reproduce the correct value of the dark-matter density is the well-tempered neutralino, which corresponds to the boundary between a pure bino and a pure higgsino or wino. We study the properties of well-tempered neutralinos and we propose a simple limit of split supersymmetry that realizes this situation.

Arkani-Hamed, N. [Jefferson Laboratory of Physics, Harvard University, Cambridge, MA 02138 (United States); Delgado, A. [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)]. E-mail: antonio.delgado@cern.ch; Giudice, G.F. [CERN, Theory Division, CH-1211 Geneva 23 (Switzerland)

2006-05-01

94

Winter Storm Fire Safety  

Science.gov (United States)

... with the Media Fire Protection Technology Winter fire safety outreach materials These free materials are yours to ... messages from the U.S. Fire Administration Winter fire safety infographic Download the infographic PDF 1.9 MB ...

95

Concussion in Winter Sports  

Science.gov (United States)

... this? Submit Button CDC Features Concussion in Winter Sports Share Compartir Get prepared for concussions on and ... to enjoy, practice, and compete in various winter sports. There's no doubt that these sports are a ...

96

Tempering of AISI 403 stainless steel  

Energy Technology Data Exchange (ETDEWEB)

The tempering behaviour of AISI 403 martensitic stainless steel over the temperature range from 480 to 720 C has been investigated, with particular attention being paid to the secondary hardening and sensitization effects produced by the formation of alloy carbides during tempering. The secondary hardening effect was determined by means of a standard hardness test. The extent of sensitization and its effect on the mechanical properties of the tempered steel were assessed by means of a modified Strauss test and a low speed tensile test in brine respectively. The results show that the following four distinctive processes occurred during tempering of AISI 403 martensitic stainless steel: annealing, secondary hardening, sensitization and healing. The tempering conditions over which each of these four processes dominates are presented in the form of a tempering map for easy reference. (orig.)

Lim, L.C. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (Singapore)); Lai, M.O. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (Singapore)); Ma, J. (Dept. of Mechanical and Production Engineering, National Univ. of Singapore (Singapore)); Northwood, D.O. (Dept. of Mechanical Engineering, Univ. of Windsor, Windsor, Ontario, ON (Canada)); Miao Baihe (Dept. of Mechanical Engineering, Univ. of Windsor, Windsor, Ontario, ON (Canada))

1993-11-01

97

PERMEABILITY, WETNESS AND CREEP OF TEMPERATE ICE  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Ice is said to be temperate when it is in local equilibrium with water veins and water inclusions (1,2). Temperate ice remains a poorly understood material offering a large field for investigation. Pressure solution of air in percolating water explains why, in temperate glaciers, ice becomes progressively bubble-free between 100 and 200 m in depth (3). Emptying of large air bubbles (formed by coalescence of several hundred of small ones) through capillary veins is not excluded, however. Perme...

Lliboutry, L.

1987-01-01

98

Stress effect on martensite tempering process  

International Nuclear Information System (INIS)

Influence has been studied of uxial tensile stress at 200 deg C on structure and mechanical behaviour of martensite in steels 20KhG and 40 ZGS. Under the influence of stresses exceeding (0.4 - 0.5)X sigmasub(0.2) applied during tempering elastic strain becomes partly plastic. Consequently, the residual micro stresses decrease, the X-ray line thus becoming narrower and resistance to minor plastic deformations increasing. Stresses applied during tempering (> 0.5 sigmasub(0.2)) accelerate the relaxation of residual microstresses with comparison to common tempering. No influence of stressed tempering on decomposition processes has been observed under the above conditions

99

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber [...] laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding speed and 1200 W laser power. However, both welded materials and heat-affected zones presented high hardness and negligible plastic deformation. In order to produce useful engineering parts, it was suggested a tempering treatment for 2 hours at temperatures of 200 or 400ºC. Tensile mechanical testing has shown that welded and tempered coupons presented both yield and maximum strengths comparable to the unwelded material. On the other hand, a maximum elongation of about 4% was obtained, in comparison with 12% from the bulk sample.

Sheila Medeiros de, Carvalho; Milton Sérgio Fernandes de, Lima.

2012-03-01

100

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber [...] laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding speed and 1200 W laser power. However, both welded materials and heat-affected zones presented high hardness and negligible plastic deformation. In order to produce useful engineering parts, it was suggested a tempering treatment for 2 hours at temperatures of 200 or 400ºC. Tensile mechanical testing has shown that welded and tempered coupons presented both yield and maximum strengths comparable to the unwelded material. On the other hand, a maximum elongation of about 4% was obtained, in comparison with 12% from the bulk sample.

Sheila Medeiros de, Carvalho; Milton Sérgio Fernandes de, Lima.

 
 
 
 
101

Mechanism of Secondary Hardening in Rapid Tempering of Dual-Phase Steel  

Science.gov (United States)

Dual-phase steel with ferrite-martensite-bainite microstructure exhibited secondary hardening in the subcritical heat affected zone during fiber laser welding. Rapid isothermal tempering conducted in a Gleeble simulator also indicated occurrence of secondary hardening at 773 K (500 °C), as confirmed by plotting the tempered hardness against the Holloman-Jaffe parameter. Isothermally tempered specimens were characterized by analytic transmission electron microscopy and high-angle annular dark-field imaging. The cementite (Fe3C) and TiC located in the bainite phase of DP steel decomposed upon rapid tempering to form needle-shaped Mo2C (aspect ratio ranging from 10 to 25) and plate-shaped M4C3 carbides giving rise to secondary hardening. Precipitation of these thermodynamically stable and coherent carbides promoted the hardening phenomenon. However, complex carbides were only seen in the tempered bainite and were not detected in the tempered martensite. The martensite phase decomposed into ferrite and spherical Fe3C, and interlath-retained austenite decomposed into ferrite and elongated carbide.

Saha, Dulal Chandra; Nayak, Sashank S.; Biro, Elliot; Gerlich, Adrian P.; Zhou, Y.

2014-12-01

102

Preventive maintenance technique by temper bead welding for reactor vessel  

International Nuclear Information System (INIS)

Pressurized Water Reactor (PWR) plant has some dissimilar weld joint between main components which are made of Low Alloy Steel and piping which is made of Stainless Steel. Previous plants' dissimilar weld joints are made of Alloy 600 which is low resistance to Primary Water Stress Corrosion Cracking (PWSCC). It is reported that PWSCC is occurred in some plants. The preventive maintenance technique against PWSCC is needed immediately. One solution is the improvement of the material, for example, the inner surface of Alloy 600 is replaced by welding Alloy 690 which is high resistance to PWSCC. Generally, Heat Affected Zone (HAZ) of low alloy steel after welding is required Post Weld Heat Treatment (PWHT), but it is so hard that this operation has to be accomplished in site. So it is necessary to attempt the improvement of HAZ by temper bead welding which isn't needed PWHT. Temper bead welding is that HAZ of 1st weld layer is appropriately covered with heat of after 2nd weld layer, then the mechanical performance of HAZ is improved as well as PWHT. Conventional temper bead welding is required pre-heat and post-heat treatment. However it is impossible to set up the heater due to environment around the dissimilar weld joint in some plants, the development of ambient temperature temper bead welding technique which isn't needed pre-heat and post-heat treatment is expected. It is confirmed that the mechanical performance and the material texture are improved by setting the appropriate welding condition with many welding test pieces. Then, the preventive maintenances called INLAY method are completed in some actual plants. (author)

103

Difficult Student. A Tale of Temper Tantrums.  

Science.gov (United States)

An elementary teacher discusses her methods of dealing with a fourth grader who threw temper tantrums when he could not do his work. She offered to bring her dog to school if he showed self-control for a week. He worked hard, avoided temper tantrums, and his positive behavior was rewarded. (SM)

Roedell, Carlyn Hove

1991-01-01

104

Parallel tempering for the traveling salesman problem  

Energy Technology Data Exchange (ETDEWEB)

We explore the potential of parallel tempering as a combinatorial optimization method, applying it to the traveling salesman problem. We compare simulation results of parallel tempering with a benchmark implementation of simulated annealing, and study how different choices of parameters affect the relative performance of the two methods. We find that a straightforward implementation of parallel tempering can outperform simulated annealing in several crucial respects. When parameters are chosen appropriately, both methods yield close approximation to the actual minimum distance for an instance with 200 nodes. However, parallel tempering yields more consistently accurate results when a series of independent simulations are performed. Our results suggest that parallel tempering might offer a simple but powerful alternative to simulated annealing for combinatorial optimization problems.

Percus, Allon [Los Alamos National Laboratory; Wang, Richard [UCLA MATH DEPT; Hyman, Jeffrey [UCLA MATH DEPT; Caflisch, Russel [UCLA MATH DEPT

2008-01-01

105

Development of temper bead technique applied to dissimilar weld joints of nuclear pressure vessels  

International Nuclear Information System (INIS)

The temper bead technique was developed for the replacement of dissimilar welded joints between stainless steel pipes and low alloy steel nozzles overlaid by nickel base alloy. The heat affected zone of the base metal produced by the first layer weld was refined and tempered by the heat input of the following weld layers with adequate welding conditions. The hardness distributions were equivalent and the Charpy impact properties were superior to those of the postweld heat treated weld after conventional welding. The distributions of residual stresses were also equivalent to those of postweld heat treatment because the materials were dissimilar. This method has passed the verification test of the JAPEIC. (author)

106

Tempered relaxation with clustering patterns  

International Nuclear Information System (INIS)

This work is motivated by the relaxation data for materials which exhibit a change of the relationship between the fractional power-law exponents when different relaxation peaks in their dielectric susceptibility are observed. Within the proposed framework we derive a frequency-domain relaxation function fitting the whole range of the two-power-law dielectric spectroscopy data with independent low- and high-frequency fractional exponents ? and ??, respectively. We show that this effect results from a contribution of different processes. For high frequencies it is determined by random stops and movement of relaxing components, and the low-frequency slope is caused by clustering in their temporal changes. -- Highlights: ? Further development in the theory of tempered relaxation. ? Based on the subordination of random processes with finite moments. ? Derived the relaxation function fitting the whole range of two-power-law data. ? Independence of low- and high-frequency fractional exponents in susceptibility.

107

Mapping Forest Fire Susceptibility in Temperate Mountain Areas with Expert Knowledge. A Case Study from Iezer Mountains, Romanian Carpathians  

Science.gov (United States)

Forest fires in Romanian Carpathians became a frequent phenomenon during the last decade, although local climate and other environmental features did not create typical conditions. From 2004, forest fires affect in Romania more than 100 hectares/year of different forest types (deciduous and coniferous). Their magnitude and frequency are not known, since a historical forest fire inventory does not exist (only press papers and local witness for some selected events). Forest fires features the summer dry periods but there are dry autumns and early winter periods with events of different magnitudes. The application we propose is based on an empirical modeling of forest fire susceptibility in a typical mountain area from the Southern Carpathians, the Iezer Mountains (2462 m). The study area features almost all the altitudinal vegetation zones of the European temperate mountains, from the beech zone, to the coniferous zone, the subalpine and the alpine zones (Mihai et al., 2007). The analysis combines GIS and remote sensing models (Chuvieco et al., 2012), starting from the ideas that forest fires are featured by the ignition zones and then by the fire propagation zones. The first data layer (ignition zones) is the result of the crossing between the ignition factors: lightning - points of multitemporal occurence and anthropogenic activities (grazing, tourism and traffic) and the ignition zones (forest fuel zonation - forest stands, soil cover and topoclimatic factor zonation). This data is modelled from different sources: the MODIS imagery fire product (Hantson et al., 2012), detailed topographic maps, multitemporal orthophotos at 0.5 m resolution, Landsat multispectral imagery, forestry cadastre maps, detailed soil maps, meteorological data (the WorldClim digital database) as well as the field survey (mapping using GPS and local observation). The second data layer (fire propagation zones) is the result of the crossing between the forest fuel zonation, obtained with the help of forestry data, the wind regime data and the topographic features of the mountain area (elevation, slope declivity, slope aspect). The analysis also consider the insolation degree of mountain slopes, that creates favourable conditions for fire propagation between different canopies. These data layers are integrated within a simple GIS analysis in order to intersect the ignition zones with the fire propagation zones in order to obtain the potential areas to be affected by fire. The digital map show three levels of forest fire susceptibility, differenced on the basis of expert knowledge. The map can be validated from the statistical point of view with the polygons of the forest fire affected areas mapped from Landsat TM, ETM+ and OLI satellite imagery. The mapping results could be integrated within the forest management strategies and especially within the forest cadastre and development maps (updated every ten years). The result can confirm that the data gap in terms of forest fire events can be filled with expert knowledge. References Chuvieco, E, Aguado, I., Jurdao, S., Pettinari, M., Yebra, M., Salas, J., Hantson, S., de la Riva, J., Ibarra, P., Rodrigues, M., Echeverria, M., Azqueta, D., Roman, M., Bastarrika, A., Martinez, S., Recondo, C., Zapico, E., Martinez-Vega F.J. (2012) Integrating geospatial information into fire risk assessment, International Journal of Wildland Fire, 2,2, 69-86. Hantson, S., Padilla, M., Corti., D, Chuvieco, E. (2013) Strenghts and weaknesses of MODIS hotspots to characterize Global fire occurence, Remote Sensing of Environment, 131, 1, 152-159. Mihai, B., Savulescu, I.,Sandric, I. (2007) Change detection analysis (1986/2002) for the alpine, subalpine and forest landscape in Iezer Mountains (Southern Carpathians, Romania), Mountain Research and Development, 27, 250-258.

Mihai, Bogdan; Savulescu, Ionut

2014-05-01

108

Winter Olympic Sports  

Science.gov (United States)

Exploring Winter Olympic Sports Let's take a look at some of the different winter olympic sports Alpine Skiing Biathalon Bobsleigh Cross country Curling Figure Skating Freestyle skiing Ice Hockey Luge Nordic Combined Short track speed skating Skeleton Ski Jumping Snowboard Speed Skating ...

Keller, Mrs.

2010-01-23

109

Winters fuels report  

International Nuclear Information System (INIS)

The outlook for distillate fuel oil this winter is for increased demand and a return to normal inventory patterns, assuming a resumption of normal, cooler weather than last winter. With industrial production expected to grow slightly from last winter's pace, overall consumption is projected to increase 3 percent from last winter, to 3.4 million barrels per day during the heating season (October 1, 1995-March 31, 1996). Much of the supply win come from stock drawdowns and refinery production. Estimates for the winter are from the Energy Information Administration's (EIA) 4th Quarter 1995 Short-Tenn Energy Outlook (STEO) Mid-World Oil Price Case forecast. Inventories in place on September 30, 1995, of 132 million barrels were 9 percent below the unusually high year-earlier level. Inventories of high-sulfur distillate fuel oil, the principal type used for heating, were 13 percent lower than a year earlier. Supply problems are not anticipated because refinery production and the ready availability of imports should be adequate to meet demand. Residential heating off prices are expected to be somewhat higher than last winter's, as the effects of lower crude oil prices are offset by lower distillate inventories. Heating oil is forecast to average $0.92 per gallon, the highest price since the winter of 1992-93. Diesel fuel (including tax) is predicted to be slightly higher than last year at $1.13 per gallon. This article focuses on the winter assessment for distillate fuel oil, how well last year's STEO winter outlook compared to actual events, and expectations for the coming winter. Additional analyses include regional low-sulfur and high-sulfur distillate supply, demand, and prices, and recent trends in distillate fuel oil inventories

110

Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel  

Energy Technology Data Exchange (ETDEWEB)

Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

Mizuno, R.; Matsuda, F. [NDE Center, Japan Power Engineering and Inspection Corp. (Japan); Brziak, P. [Welding Research Inst. - Industrial Inst. of Slovak Republic (Slovakia); Lomozik, M. [Inst. of Welding (Poland)

2004-07-01

111

Appropriate welding conditions of temper bead weld repair for SQV2A pressure vessel steel  

International Nuclear Information System (INIS)

Temper bead welding technique is one of the most important repair welding methods for large structures for which it is difficult to perform the specified post weld heat treatment. In this study, appropriate temper bead welding conditions to improve the characteristics of heat affected zone (HAZ) are studied using pressure vessel steel SQV2A corresponding to ASTM A533 Type B Class 1. Thermal/mechanical simulator is employed to give specimens welding thermal cycles from single to quadruple cycle. Charpy absorbed energy and hardness of simulated CGHAZ by first cycle were degraded as compared with base metal. Improvability of these degradations by subsequent cycles is discussed and appropriate temper bead thermal cycles are clarified. When the peak temperature lower than Ac1 and near Ac1 in the second thermal cycle is applied to CGAHZ by first thermal cycle, the characteristics of CGHAZ improve enough. When the other peak temperatures (that is, higher than Ac1) in the second thermal cycle are applied to the CGHAZ, third or more thermal cycle temper bead process should be applied to improve the properties. Appropriate weld condition ranges are selected based on the above results. The validity of the selected ranges is verified by the temper bead welding test. (orig.)

112

Drilling in tempered glass – modelling and experiments  

DEFF Research Database (Denmark)

The present paper reports experimentally and numerically obtained results for the process of drilling in tempered glass. The experimental results are drilling depths on the edge in 19mm tempered glass with a known residual stress state measured by a scattered light polariscope. The experiments have been modelled using a state-of-the-art model and compared with satisfying result to the performed experiments. The numerical model has been used for a parametric study, investigating the redistribution of residual stresses during the process of drilling. This is done for investigating the possibility of applying forces in such holes and thereby being able to mechanically assemble tempered glass without the need of drilling holes before the tempering process. The paper is the result of currently ongoing research and the results should be treated as so.

Nielsen, Jens Henrik

113

Deoxidation procedure and tempered martensite embrittlement  

International Nuclear Information System (INIS)

Tendency to tempered martensite embrittlement of the silicon-killed and the silicon-free deoxidized 40Kh steel and the 20KhG steel contained deliberate additions of silica was investigated. The silicon-free 40Kh steel and 20KhG steel without the introduction of SiO2 do not show such a tendency. The hardening temperature decrease intensifies the effects connected with tempered martensite embrittlement

114

Tempering resistance of martensite strain hardening  

International Nuclear Information System (INIS)

The volumetric, the resistometric, X-ray and internal friction methods are employed to investigate the mechanical and the physical properties of 28Kh3SNMVFA steel in heating after deformation from 0 to 20 % in martensitic state (hardening and tempering at 200 deg C), and the effect is determined of the subsequent tempering at 200-600 deg C. It has been shown that the strength of the deformed steel after deformation and tempering at temperatures of 500 deg C and over is higher than that of a non-deformed one. This difference is the greater, the higher the degree of deformation. A special carbide M7C3 has been found after tempering at 500-550 deg C in a steel deformed by 20%. No special carbides have been detected at lesser degrees of deformation. The best complex of mechanical properties of 28Kh3SNMVFA steel is obtained after the following treatment: hardening, tempering at 200 deg C, rolling with a 20% degree of deformation, tempering at 200 deg C. The strength of the deformed steel in short-time tests at elevated temperatures (up to 500 deg C) is found to be higher than that of the hardened steel

115

Woodland communities in the Chilean cold-temperate zone (Baker and Pascua basins): Floristic composition and morpho-ecological transition / Comunidades leñosas en la zona chilena frío-templada (cuencas de los ríos Baker y Pascua): Composición florística y transición morfo-ecológica  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: English Abstract in spanish Este estudio describe la composición florística y la transición morfo-ecológica de las comunidades leñosas ocurriendo a través de un gradiente climático en la zona templada fría de la Patagonia chilena. Se establecieron un total de 256 relevamientos fitosociológicos a través de un transecto NE-SO de [...] 150 km para registrar las especies de plantas vasculares. Técnicas de clasificación (análisis de conglomerados) y ordenación (análisis de componentes principales) fueron usadas para segregar y examinar comunidades. Se computaron indicadores de biodiversidad incluyendo riqueza y abundancia de especies nativas y exóticas, valores de importancia, formas de vida de Raunkiaer, índices de diversidad y especies indicadoras para describir atributos comunitarios. La diversidad Beta fue analizada usando el coeficiente de Jaccard. Se discuten también las perturbaciones antropogénicas que actualmente afectan a la vegetación. En total se segregaron 11 comunidades pertenecientes a tres grupos ecológicos: a) comunidades leñosas meso-higromórficas pertenecientes a la cuenca del Baker, conformada principalmente de bosques caducifolios conteniendo valores relativos intermedios de riqueza y diversidad, pero las mayores riquezas de exóticas; b) comunidades leñosas higromórficas pertenecientes al segmento sur de la cuenca del río Baker y a través de toda la cuenca del río Pascua, compuesta de bosques siempreverdes conteniendo los mayores valores de riqueza y diversidad y muy baja riqueza de exóticas, y c) comunidades leñosas achaparradas alto-andinas, distribuidas en lugares de alta elevación en ambas cuencas, compuestas de krummholz conteniendo la menor riqueza y diversidad, sin presencia de especies introducidas. El reemplazo de comunidades caduficolias por siempreverdes en sentido norte-sur sucede alrededor de la latitud 48°S. Perturbaciones antrópicas como la tala de madera por propietarios rurales, sobrepastoreo por ganado doméstico y ampliaciones en los caminos, están provocando invasiones biológicas en los bosques de la cuenca del río Baker, mientras que los bosques de la cuenca del río Pascua, donde no ocurre poblamiento humano, permanecen prístinos Abstract in english This study describes the floristic composition and morpho-ecological transition of woodlands along a climatic gradient in the southern cold temperate zone of Chilean Patagonia. A total of 256 phytosociological relevés were performed across a 150 km NE-SW transect to record vascular plant species. Cl [...] assification (cluster analysis) and ordination (principal component analysis) techniques were used to segregate and examine the communities. Biodiversity indicators including richness and abundances of species natives and exotics, importance values, Raunkiaer plant life-forms, diversity indices and indicator species were calculated to describe community attributes. Beta diversity was analysed using the Jaccard index. Additionally, the current anthropogenic disturbances affecting this vegetation are discussed. In total, 11 woodland communities belonging to 3 morpho-ecological groups were segregated: a) meso-hygromorphic woodlands belonging to the Baker basin, mostly composed of deciduous forests containing relatively moderate values of richness and diversity but high richness of exotics, b) hygromorphic woodlands belonging to the southern segment of the Baker basin and along the Pascua basin, composed of evergreen forest containing the relatively highest values of richness and diversity and very low richness of exotics and c) high-Andean dwarf woodlands distributed at high elevations in both basins, composed of deciduous krummholz containing the lowest richness and diversity and no exotics. The replacement of deciduous by evergreen communities at low elevations occurs around the latitude 48°S. Anthropogenic disturbances like logging by rural landowners, overgrazing by livestock and road construction are promoting biological invasions in the Baker basin fo

OSVALDO J, VIDAL; JAN R, BANNISTER; VÍCTOR, SANDOVAL; YESSICA, PÉREZ; CARLOS, RAMÍREZ.

116

Woodland communities in the Chilean cold-temperate zone (Baker and Pascua basins: Floristic composition and morpho-ecological transition Comunidades leñosas en la zona chilena frío-templada (cuencas de los ríos Baker y Pascua: Composición florística y transición morfo-ecológica  

Directory of Open Access Journals (Sweden)

Full Text Available This study describes the floristic composition and morpho-ecological transition of woodlands along a climatic gradient in the southern cold temperate zone of Chilean Patagonia. A total of 256 phytosociological relevés were performed across a 150 km NE-SW transect to record vascular plant species. Classification (cluster analysis and ordination (principal component analysis techniques were used to segregate and examine the communities. Biodiversity indicators including richness and abundances of species natives and exotics, importance values, Raunkiaer plant life-forms, diversity indices and indicator species were calculated to describe community attributes. Beta diversity was analysed using the Jaccard index. Additionally, the current anthropogenic disturbances affecting this vegetation are discussed. In total, 11 woodland communities belonging to 3 morpho-ecological groups were segregated: a meso-hygromorphic woodlands belonging to the Baker basin, mostly composed of deciduous forests containing relatively moderate values of richness and diversity but high richness of exotics, b hygromorphic woodlands belonging to the southern segment of the Baker basin and along the Pascua basin, composed of evergreen forest containing the relatively highest values of richness and diversity and very low richness of exotics and c high-Andean dwarf woodlands distributed at high elevations in both basins, composed of deciduous krummholz containing the lowest richness and diversity and no exotics. The replacement of deciduous by evergreen communities at low elevations occurs around the latitude 48°S. Anthropogenic disturbances like logging by rural landowners, overgrazing by livestock and road construction are promoting biological invasions in the Baker basin forests, while the forests in the Pascua basin remain pristine since no human population occurs thereEste estudio describe la composición florística y la transición morfo-ecológica de las comunidades leñosas ocurriendo a través de un gradiente climático en la zona templada fría de la Patagonia chilena. Se establecieron un total de 256 relevamientos fitosociológicos a través de un transecto NE-SO de 150 km para registrar las especies de plantas vasculares. Técnicas de clasificación (análisis de conglomerados y ordenación (análisis de componentes principales fueron usadas para segregar y examinar comunidades. Se computaron indicadores de biodiversidad incluyendo riqueza y abundancia de especies nativas y exóticas, valores de importancia, formas de vida de Raunkiaer, índices de diversidad y especies indicadoras para describir atributos comunitarios. La diversidad Beta fue analizada usando el coeficiente de Jaccard. Se discuten también las perturbaciones antropogénicas que actualmente afectan a la vegetación. En total se segregaron 11 comunidades pertenecientes a tres grupos ecológicos: a comunidades leñosas meso-higromórficas pertenecientes a la cuenca del Baker, conformada principalmente de bosques caducifolios conteniendo valores relativos intermedios de riqueza y diversidad, pero las mayores riquezas de exóticas; b comunidades leñosas higromórficas pertenecientes al segmento sur de la cuenca del río Baker y a través de toda la cuenca del río Pascua, compuesta de bosques siempreverdes conteniendo los mayores valores de riqueza y diversidad y muy baja riqueza de exóticas, y c comunidades leñosas achaparradas alto-andinas, distribuidas en lugares de alta elevación en ambas cuencas, compuestas de krummholz conteniendo la menor riqueza y diversidad, sin presencia de especies introducidas. El reemplazo de comunidades caduficolias por siempreverdes en sentido norte-sur sucede alrededor de la latitud 48°S. Perturbaciones antrópicas como la tala de madera por propietarios rurales, sobrepastoreo por ganado doméstico y ampliaciones en los caminos, están provocando invasiones biológicas en los bosques de la cuenca del río Baker, mientras que los bosques de la cuenca del río Pascua, donde no ocurre poblamiento humano, permanecen prístin

OSVALDO J VIDAL

2011-01-01

117

Winter Weather: Hypothermia  

Science.gov (United States)

... and Cleanup Workers Hurricanes PSAs ASL Videos: Hurricanes Landslides & Mudslides Lightning Lightning Safety Tips First Aid Recommendations ... Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis Volcanoes Wildfires Winter Weather Hypothermia Language: ...

118

First Temperate Exoplanet Sized Up  

Science.gov (United States)

Combining observations from the CoRoT satellite and the ESO HARPS instrument, astronomers have discovered the first "normal" exoplanet that can be studied in great detail. Designated Corot-9b, the planet regularly passes in front of a star similar to the Sun located 1500 light-years away from Earth towards the constellation of Serpens (the Snake). "This is a normal, temperate exoplanet just like dozens we already know, but this is the first whose properties we can study in depth," says Claire Moutou, who is part of the international team of 60 astronomers that made the discovery. "It is bound to become a Rosetta stone in exoplanet research." "Corot-9b is the first exoplanet that really does resemble planets in our solar system," adds lead author Hans Deeg. "It has the size of Jupiter and an orbit similar to that of Mercury." "Like our own giant planets, Jupiter and Saturn, the planet is mostly made of hydrogen and helium," says team member Tristan Guillot, "and it may contain up to 20 Earth masses of other elements, including water and rock at high temperatures and pressures." Corot-9b passes in front of its host star every 95 days, as seen from Earth [1]. This "transit" lasts for about 8 hours, and provides astronomers with much additional information on the planet. This is fortunate as the gas giant shares many features with the majority of exoplanets discovered so far [2]. "Our analysis has provided more information on Corot-9b than for other exoplanets of the same type," says co-author Didier Queloz. "It may open up a new field of research to understand the atmospheres of moderate- and low-temperature planets, and in particular a completely new window in our understanding of low-temperature chemistry." More than 400 exoplanets have been discovered so far, 70 of them through the transit method. Corot-9b is special in that its distance from its host star is about ten times larger than that of any planet previously discovered by this method. And unlike all such exoplanets, the planet has a temperate climate. The temperature of its gaseous surface is expected to be between 160 degrees and minus twenty degrees Celsius, with minimal variations between day and night. The exact value depends on the possible presence of a layer of highly reflective clouds. The CoRoT satellite, operated by the French space agency CNES [3], identified the planet after 145 days of observations during the summer of 2008. Observations with the very successful ESO exoplanet hunter - the HARPS instrument attached to the 3.6-metre ESO telescope at La Silla in Chile - allowed the astronomers to measure its mass, confirming that Corot-9b is indeed an exoplanet, with a mass about 80% the mass of Jupiter. This finding is being published in this week's edition of the journal Nature. Notes [1] A planetary transit occurs when a celestial body passes in front of its host star and blocks some of the star's light. This type of eclipse causes changes in the apparent brightness of the star and enables the planet's diameter to be measured. Combined with radial velocity measurements made by the HARPS spectrograph, it is also possible to deduce the mass and, hence, the density of the planet. It is this combination that allows astronomers to study this object in great detail. The fact that it is transiting - but nevertheless not so close to its star to be a "hot Jupiter" - is what makes this object uniquely well suited for further studies. [2] Temperate gas giants are, so far, the largest known group of exoplanets discovered. [3] The CoRoT (Convection, Rotation and Transits) space telescope was constructed by CNES, with contributions from Austria, Germany, Spain, Belgium, Brazil and the European Space Agency (ESA). It was specifically designed to detect transiting exoplanets and carry out seismological studies of stars. Its results are supplemented by observations with several ground-based telescopes, among them the IAC-80 (Teide Observatory), the Canada Fra

2010-03-01

119

Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México / Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: Spanish Abstract in spanish El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la col [...] umna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificación el resto del año. La presencia de turbulencia y nutrimentos durante el periodo de circulación favorecen el desarrollo de un florecimiento de diatomeas compuesto por especies de talla grande (p. e., Cyclotella alchichicana), las cuales se sedimentan al no ser consumidas en su totalidad. La zona bentónica profunda del lago responde a la sedimentación del florecimiento invernal de diatomeas con el desarrollo y permanencia por un periodo prolongado de anoxia hipolimnética, lo que a su vez, impide el establecimiento y desarrollo de fauna bentónica en el Lago Alchichica, favorece la pérdida interna de nitrógeno por desnitrificación y consecuentemente, conlleva a que el nitrógeno sea el elemento que más frecuentemente límite el crecimiento fitoplanctónico. Abstract in english The aim of this study is to recognize the existence of a pelagic-benthic coupling in the oligotrophic, tropical Lake Alchichica through analysis of the response of the deep benthic zone to the winter diatom bloom deposition. The water column phytoplankton biomass and the sedimentary chlorophyll a we [...] re analyzed along an annual cycle. Alchichica is a warm monomictic lake circulating in winter and stratified over the rest of the year. The presence of turbulence and nutrient availability during the mixing period, favor the development of a diatom bloom composed by large species (e. g., Cyclotella alchichicana) which are not totally consumed and settle down. The deep benthic zone responds to the sinking of the winter diatom bloom with the prompt development -and permanence for an extended period- of hypolimnetic anoxia, which in turns prevents the establishment and development of the benthic fauna in Lake Alchichica, and favors the internal loss of nitrogen through denitrification, and accordingly, promotes nitrogen to be the limiting nutrient for phytoplankton growth.

Javier, Alcocer; Elva, Escobar; Luis A., Oseguera.

120

Acoplamiento pelágico-bentónico: respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas en el lago oligotrófico Alchichica, Puebla, México Pelagic-benthic coupling: deep benthic zone response to winter diatom bloom sinking in oligotrophic Lake Alchichica, Puebla, Mexico  

Directory of Open Access Journals (Sweden)

Full Text Available El objetivo del presente estudio es reconocer la existencia de un acoplamiento pelágico-bentónico en el lago oligotrófico tropical Alchichica evaluando la respuesta de la zona bentónica profunda a la sedimentación del florecimiento invernal de diatomeas. Se midió la biomasa fitoplanctónica en la columna de agua a lo largo de un ciclo anual, al igual que la concentración de clorofila a sedimentaria. Alchichica es un lago monomíctico cálido con un periodo de circulación invernal y estratificación el resto del año. La presencia de turbulencia y nutrimentos durante el periodo de circulación favorecen el desarrollo de un florecimiento de diatomeas compuesto por especies de talla grande (p. e., Cyclotella alchichicana, las cuales se sedimentan al no ser consumidas en su totalidad. La zona bentónica profunda del lago responde a la sedimentación del florecimiento invernal de diatomeas con el desarrollo y permanencia por un periodo prolongado de anoxia hipolimnética, lo que a su vez, impide el establecimiento y desarrollo de fauna bentónica en el Lago Alchichica, favorece la pérdida interna de nitrógeno por desnitrificación y consecuentemente, conlleva a que el nitrógeno sea el elemento que más frecuentemente límite el crecimiento fitoplanctónico.The aim of this study is to recognize the existence of a pelagic-benthic coupling in the oligotrophic, tropical Lake Alchichica through analysis of the response of the deep benthic zone to the winter diatom bloom deposition. The water column phytoplankton biomass and the sedimentary chlorophyll a were analyzed along an annual cycle. Alchichica is a warm monomictic lake circulating in winter and stratified over the rest of the year. The presence of turbulence and nutrient availability during the mixing period, favor the development of a diatom bloom composed by large species (e. g., Cyclotella alchichicana which are not totally consumed and settle down. The deep benthic zone responds to the sinking of the winter diatom bloom with the prompt development -and permanence for an extended period- of hypolimnetic anoxia, which in turns prevents the establishment and development of the benthic fauna in Lake Alchichica, and favors the internal loss of nitrogen through denitrification, and accordingly, promotes nitrogen to be the limiting nutrient for phytoplankton growth.

Javier Alcocer

2008-08-01

 
 
 
 
121

Temperate origins of long-distance seasonal migration in New World songbirds.  

Science.gov (United States)

Migratory species exhibit seasonal variation in their geographic ranges, often inhabiting geographically and ecologically distinct breeding and nonbreeding areas. The complicated geography of seasonal migration has long posed a challenge for inferring the geographic origins of migratory species as well as evolutionary sequences of change in migratory behavior. To address this challenge, we developed a phylogenetic model of the joint evolution of breeding and nonbreeding (winter) ranges and applied it to the inference of biogeographic history in the emberizoid passerine birds. We found that seasonal migration between breeding ranges in North America and winter ranges in the Neotropics evolved primarily via shifts of winter ranges toward the tropics from ancestral ranges in North America. This result contrasts with a dominant paradigm that hypothesized migration evolving out of the tropics via shifts of the breeding ranges. We also show that major lineages of tropical, sedentary emberizoids are derived from northern, migratory ancestors. In these lineages, the winter ranges served as a biogeographic conduit for temperate-to-tropical colonization: winter-range shifts toward the tropics during the evolution of long-distance migration often preceded southward shifts of breeding ranges, the loss of migration, and in situ tropical diversification. Meanwhile, the evolution of long-distance migration enabled the persistence of old lineages in North America. These results illuminate how the evolution of seasonal migration has contributed to greater niche conservatism among tropical members of this diverse avian radiation. PMID:25092321

Winger, Benjamin M; Barker, F Keith; Ree, Richard H

2014-08-19

122

Seasonal variation in light, mixing depth and primary productivity in temperate northern hemisphere waters  

Science.gov (United States)

In this exercise students work with light, temperature, and phytoplankton biomass proxy (chlorophyll a concentration) data to; Become more skilled in reading and interpreting semi log graphs, temperature profiles, and time series plots. Practice unit conversions. Gain an understanding of k, the attenuation coefficient for nondirectional light. See how the depth of the photic zone and the surface mixed layer varies seasonally at temperate latitudes and how this relates to seasonal phytoplankton productivity dynamics.

Sahl, Lauren

123

Hydrogen embrittlement susceptibility of tempered 9%Cr-1% Mo steel  

International Nuclear Information System (INIS)

The influence of the subsurface hydrogen activity on the hydrogen embrittlement (HE) susceptibility of a tempered 9%Cr-1%Mo ferritic-martensitic steel (T91) has been studied by constant extension rate tests (CERT) performed under cathodic charging during straining at 20 degrees C. changes in the hydrogen activity on the surface were obtained by varying the cathodic current density imposed during a tensile test completed to fracture. The broken samples were observed by scanning electron microscopy (SEM). The results show a strong dependence of the extent of the brittle zone with the subsurface hydrogen activity. This effect could be attributed to an enhancement of the apparent diffusion coefficient of hydrogen when increasing H activity. Increasing H activity could enhance both the trapping rate on pre-existing and strain-induced traps and H dragging by moving traps such as dislocations. (authors)

124

Plasmodium vivax populations revisited: mitochondrial genomes of temperate strains in Asia suggest ancient population expansion  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Plasmodium vivax is the most widely distributed human malaria parasite outside of Africa, and its range extends well into the temperate zones. Previous studies provided evidence for vivax population differentiation, but temperate vivax parasites were not well represented in these analyses. Here we address this deficit by using complete mitochondrial (mt genome sequences to elucidate the broad genetic diversity and population structure of P. vivax from temperate regions in East and Southeast Asia. Results From the complete mtDNA sequences of 99 clinical samples collected in China, Myanmar and Korea, a total of 30 different haplotypes were identified from 26 polymorphic sites. Significant differentiation between different East and Southeast Asian parasite populations was observed except for the comparison between populations from Korea and southern China. Haplotype patterns and structure diversity analysis showed coexistence of two different groups in East Asia, which were genetically related to the Southeast Asian population and Myanmar population, respectively. The demographic history of P. vivax, examined using neutrality tests and mismatch distribution analyses, revealed population expansion events across the entire P. vivax range and the Myanmar population. Bayesian skyline analysis further supported the occurrence of ancient P. vivax population expansion. Conclusions This study provided further resolution of the population structure and evolution of P. vivax, especially in temperate/warm-temperate endemic areas of Asia. The results revealed divergence of the P. vivax populations in temperate regions of China and Korea from other populations. Multiple analyses confirmed ancient population expansion of this parasite. The extensive genetic diversity of the P. vivax populations is consistent with phenotypic plasticity of the parasites, which has implications for malaria control.

Miao Miao

2012-02-01

125

Well-Tempered Metadynamics Converges Asymptotically  

Science.gov (United States)

Metadynamics is a versatile and capable enhanced sampling method for the computational study of soft matter materials and biomolecular systems. However, over a decade of application and several attempts to give this adaptive umbrella sampling method a firm theoretical grounding prove that a rigorous convergence analysis is elusive. This Letter describes such an analysis, demonstrating that well-tempered metadynamics converges to the final state it was designed to reach and, therefore, that the simple formulas currently used to interpret the final converged state of tempered metadynamics are correct and exact. The results do not rely on any assumption that the collective variable dynamics are effectively Brownian or any idealizations of the hill deposition function; instead, they suggest new, more permissive criteria for the method to be well behaved. The results apply to tempered metadynamics with or without adaptive Gaussians or boundary corrections and whether the bias is stored approximately on a grid or exactly.

Dama, James F.; Parrinello, Michele; Voth, Gregory A.

2014-06-01

126

A Transnational Temperance Discourse? William Wells Brown, Creole Civilization, and Temperate Manners  

Directory of Open Access Journals (Sweden)

Full Text Available

In the nineteenth century, temperance movements provided the occasion for a transnational discourse. These conversations possessed an intensity throughout Britain and the United States. In America temperance often became associated with strongly nationalistic Euro-American forms of identity and internal purity. Nonetheless, African American reformers and abolitionists bound themselves to temperance ideals in forming civil societies that would heal persons and provide communal modes of democratic freedom in the aftermath and recovery from chattel slavery. This paper explores the possibilities of temperance as a transnational discourse by considering its meaning in the life and work of the African American author and activist, William Wells Brown. Brown expressed a “creole civilization” that employed the stylistics of the trickster as a unique mode of restraint that revealed a peculiar power of passivity that was able to claim efficacy over one’s life and community. This meaning of temperance diverges from and dovetails with certain European meanings of civilization that were being forged in the nineteenth century. Brown was in conversation with temperance reformers in America, Britain, and Europe. He imagined the possible meaning of temperance in African, Egyptian, Christian, and Islamic civilizations. He speculated upon the possibility of temperance as a defining characteristic of a transnational civilization and culture that would provide spaces for the expression of democratic freedom. Brown reimagined temperance as a form of corporeal restraint that offered a direct and sacred relation to the land, space, people that appeared in between an ethnic nationalist ethos and the European imperialistic civilization.

Carole Lynn Stewart

2011-03-01

127

Arithmetic Brownian motion subordinated by tempered stable and inverse tempered stable processes  

CERN Document Server

In the last decade the subordinated processes have become popular and found many practical applications. Therefore in this paper we examine two processes related to time-changed (subordinated) classical Brownian motion with drift (called arithmetic Brownian motion). The first one, so called normal tempered stable, is related to the tempered stable subordinator, while the second one - to the inverse tempered stable process. We compare the main properties (such as probability density functions, Laplace transforms, ensemble averaged mean squared displacements) of such two subordinated processes and propose the parameters' estimation procedures. Moreover we calibrate the analyzed systems to real data related to indoor air quality.

Wy?oma?ska, Agnieszka

2012-01-01

128

Titan's Emergence from Winter  

Science.gov (United States)

We summarize the changes in Titans thermal structure derived from Cassini CIRS and radio-occultation data during the transition from winter to early spring. Titan's surface, and middle atmosphere show noticeable seasonal change, whereas that in most of the troposphere is mated. This can be understood in terms of the relatively small radiative relaxation time in the middle atmosphere and much larger time scale in the troposphere. The surface exhibits seasonal change because the heat capacity in an annual skin depth is much smaller than that in the lowest scale height of the troposphere. Surface temperatures rise 1 K at raid and high latitudes in the winter northern hemisphere and cool in the southern hemisphere. Changes in in the middle atmosphere are more complicated. Temperatures in the middle stratosphere (approximately 1 mbar) increase by a few kelvin at mid northern latitudes, but those at high latitudes first increase as that region moves out of winter shadow, and then decrease. This probably results from the combined effect of increased solar heating as the suit moves higher in the sky and the decreased adiabatic warming as the sinking motions associated with the cross-equatorial meridional cell weaken. Consistent with this interpretation, the warm temperatures observed higher up at the winter polar stratopause cool significantly.

Flasar, F. Michael; Achterberg, Richard; Jennings, Donald; Schinder, Paul

2011-01-01

129

The physiology of diving in a north-temperate and three tropical turtle species.  

Science.gov (United States)

We examined changes in blood gases, plasma ions, and acid-base status during prolonged submergence (6 h) of four aquatic turtle species in aerated water at 20 degrees C. Our objective was to determine whether the temperate species, Chrysemys picta bellii, exhibits greater tolerance to submergence apnea than the tropical species, Pelomedusa subrufa, Elseya novaeguineae, and Emydura subglobosa. Blood was sampled from indwelling arterial catheters for measurements of blood PO2, PCO2, pH, and hematocrit and for plasma concentrations of lactate, glucose, Na+, K+, Cl-, total Ca, and total Mg. The pattern of change was similar in all species: a combined respiratory and metabolic acidosis associated with a marked decrease of blood PO2. The severity of the acidosis developed in the temperate species, however, was significantly less than that of the tropical turtles. Lactate rose significantly and HCO3- fell proportionately in all turtles; changes in other plasma ion concentrations were small but were generally in the directions consistent with compensatory exchanges with other body compartments; i.e., cations (K+, Ca, and Mg increased) and anions (Cl- decreased). The results indicate that hypoxia tolerance is a conserved trait in turtles, even in those that do not experience enforced winter submergence, and that the temperate species may be superior in this capacity because of reduced metabolic rate. PMID:10466218

Crocker, C E; Ultsch, G R; Jackson, D C

1999-07-01

130

Mercury emission from a temperate lake during autumn turnover  

International Nuclear Information System (INIS)

Lakes in temperate regions stratify during summer and winter months, creating distinct layers of water differentiated by their physical and chemical characteristics. When lakes mix in autumn and spring, mercury cycling may be affected by the chemical changes that occur during mixing. Sampling was conducted in Lake Lacawac, Eastern Pennsylvania, USA, throughout the autumn of 2007 to characterize changes in emission of gaseous elemental mercury (Hg0) from the lake surface and dissolved mercury profiles in the water column during mixing. Water chemistry and weather parameters were also measured, including dissolved organic carbon (DOC), iron, and solar radiation which have been shown to interact with mercury species. Results indicate that emission of Hg0 from the lake to the atmosphere during turnover was controlled both by solar radiation and by surface water mercury concentration. As autumn turnover progressed through the months of October and November, higher mercury concentration water from the hypolimnion mixed with epilimnetic water, increasing mercury concentration in epilimnetic waters. Dissolved absorbance was significantly correlated with mercury concentrations and with iron, but DOC concentrations were essentially constant throughout the study period and did not exhibit a relationship with either dissolved mercury concentrations or emission rates. Positive correlations between dissolved mercury and iron and manganese also suggest a role for these elements in mercury transport within the lake, but iron and manganese did not demonstrate a relationship with emission rates. This research indicates that consideration of seasonal processes in lakes is important when evaluating mercury cycling in aquatic systems

131

Development of temper-bead technique applied to dissimilar welded joints of nuclear pressure vessels  

International Nuclear Information System (INIS)

When nuclear pressure vessels made of low-alloy steel (P-3 Group 3) need repair or modification, technical standards for welding of electrical structures should be applied, and then postweld heat treatment (PWHT) should be done. However, cases in which PWHT is impractical are theoretically possible due to a variety of restrictions. To deal with such a problem, there is a regulation for repair weld technique, without PWHT, in accordance with ASME B and PV Code. This method is called temper-bead technique, which gives the weldments sufficient toughness by tempering the hardened zone of the heat-affected zone on the first layer of the base metal using the heat of the following weld beads. Because there is no regulation in Japan covering this method, a procedure is required to perform it under a special license, after a verification test has been passed. An attempt has been made to develop a method, on the supposition that the temper-bead technique is adopted for replacement of what is called dissimilar welded joints, so that a nickel base alloy is buildup welded at the tip of the nozzle of the low-alloy steel pressure vessel, and a stainless steel pipe is butt welded

132

Petrogenesis of cenozoic temperate water carbonates, South Australia  

Energy Technology Data Exchange (ETDEWEB)

The Gambier Limestone is one of several extensive, shallow water, shelf carbonates of Eocene to Miocene age exposed along the southern margin of Australia. It is muddy to grainy bryozoan calcarenite, with accessory benthonic foraminifers and echinoids. The sediments, originally composed almost entirely of calcite or Mg-calcite, have been in vadose and phreatic environments for over 10 m.y., yet are virtually unlithified. The only cements of any consequence are epitaxial on echinoids. Numerous karst features, dolines, caves, speleothems, and surface karren attest to prolonged residence in the meteoric zone. The Gambier is presently one of the best freshwater aquifiers in Australia, with most flow intergranular and through sediments with over 30% porosity. Cementation is by minor intergranular pressure solution, which has developed under overburden of less than 100 m. The overlying Naracoorte Limestone (Miocene), a calcarenite of warmer water aspect, contains numerous aragonite molds and is cemented marblehard. The authors propose that such temperate-water calcite limestones are a better model for the meteoric diagenesis of calcite sediments of all ages than aragonite-rich tropical sediments. It is probable that many similar early and middle Paleozoic calcite limestones may have been in the meteoric zone for prolonged periods, yet contain little or no petrographic or geochemical record of such exposure.

Noel, J.P.; Bone, Y.

1988-01-01

133

Initiation of winter phytoplankton blooms within the Gironde plume waters in the Bay of Biscay  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thermostratification and seasonal Light increase are generally considered the first causes of phytoplankton spring blooms in temperate waters. The objective of this study is to confirm the existence of winter phytoplankton blooms, responsible for the early exhaustion of phosphate, within the Gironde plume waters (southeast Bay of Biscay), and to understand what may initiate them so early. Two cruises, BIOMET 2 and BIOMET 3, were carried out respectively in early (8 to 21 January) and late win...

Labry, Claire; Herbland, Alain; Delmas, Daniel; Laborde, P.; Lazure, Pascal; Froidefond, J.; Jegou, Anne-marie; Sautour, B.

2001-01-01

134

Comportamiento de vacas Holstein mantenidas en un sistema de estabulación libre, en invierno, en zona árida, México / Behaviour of Holstein cows under a free housing system, in winter, in an arid zone, México  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish El objetivo de esta investigación fue evaluar el comportamiento individual y social de vacas lecheras bajo un sistema de estabulación libre durante el invierno y entre períodos de alimentación. El estudio se realizó durante 60 días en un hato productor de leche en el Estado de Aguascalientes, México [...] , con 40 vacas Holstein en producción de entre 2 a 4 años de edad. Las vacas estaban en un solo corral y con un espacio de 40 m²/vaca. Los resultados mostraron que las vacas destinaron 51% del tiempo en descansar echadas, 29% para rumiar, 10% para comer, 4% para caminar, 4% permanecieron paradas, y 2% para colear; no hubo conductas de sacudidas (movimiento costal), orejear, cabecear y patear. Para conductas sociales se observó una frecuencia de interacciones afiliativas de 6,1/hora, y 0,95/hora de interacciones agresivas; dentro de las conductas afiliativas emitidas a otras vacas se identificó una frecuencia para lamer de 4,9/hora, oler de 0,61/hora, recargarse de 0,24/ hora, montar de 0,18/hora y rascarse de 0,12/hora; dentro de las conductas agresivas se identificaron las de seguir, amenazar y topetear a otras vacas con valores de 0,63/hora, 0,10/hora y 0,22/hora, respectivamente. Las vacas presentaron conductas de mantenimiento y sociales que sugieren un estado de bienestar, atribuible a la temperatura ambiente predominante en la época de estudio, el espacio individual asignado a cada animal y al horario en que se registraron las conductas. Abstract in english The objective of this trial was to assess the social and individual behaviour of dairy cows under free housing conditions, during a winter season and between feeding periods. The study considered 60 days of observations using 40 Holstein cows (2-4 years old) from a dairy herd in the state of Aguasca [...] lientes. The cows were all kept in one pen with a space allowance of 40m²/cow. Individual behaviour data showed that cows spent 51% of their time resting in a lying position, 29% ruminating, 10% eating, 4% walking, 4% standing and 2% tail switching. No evidence of body quivering, ear twitching, head tossing or kicking was found. Social behaviour data showed that affiliation interactions occurred 6.1 times per hour and aggressive interactions 0.95 times per hour. Regarding affiliation behaviour it was found that licking, smelling, replenishing, mounting and scratching other cows occurred 4.9/hour, 0.61/hour, 0.24/hour, 0.18/hour and 0.12/hour respectively. Regarding aggressive behaviour the following was recorded: cows following, threatening and butting other cows occurred 0.63/hour, 0.10/hour and 0.22/hour respectively. The cows showed maintenance and social behaviours that suggest a welfare state attributable to the environmental temperature that was predominant during the season of study, the individual space assigned per cow and the time schedule in which the observations were made.

I., Vitela; C., Cruz-Vázquez; J., Solano.

135

Titan's Winter Polar Vortex  

Science.gov (United States)

Titan's atmosphere has provided an interesting study in contrasts and similarities with Earth's. While both have N$_2$ as the dominant constituent and comparable surface pressures $\\sim1$ bar, Titan's next most abundant molecule is CH$_4$, not O$_2$, and the dissociative breakup of CH$_4$ and N$_2$ by sunlight and electron impact leads to a suite of hydrocarbons and nitriles, and ultimately the photochemical smog that enshrouds the moon. In addition, with a 15.95-day period, Titan is a slow rotator compared to Earth. While the mean zonal terrestrial winds are geostrophic, Titan's are mostly cyclostrophic, whipping around the moon in as little as 1 day. Despite the different dynamical regime, Titan's winter stratosphere exhibits several characteristics that should be familiar to terrestrial meteorologists. The cold winter pole near the 1 -mbar level is circumscribed by strong winds (up to 190 m/s) that act as a barrier to mixing with airmasses at lower latitudes. There is evidence of enhancement of several organic species over the winter pole, indicating subsidence. The adiabatic heating associated with this subsidence gives rise to a warm anomaly at the 0.01-mbar level, raising the stratopause two scale heights above its location at equatorial latitudes. Condensate ices have been detected in Titan's lower stratosphere within the winter polar vortex from infrared spectra. Although not always unambiguously identified, their spatial distribution exhibits a sharp gradient, decreasing precipitously across the vortex away from the winter pole. The interesting question of whether there is important heterogeneous chemistry occurring within the polar vortex, analogous to that occurring in the terrestrial polar stratospheric clouds in the ozone holes, has not been addressed. The breakup of Titan's winter polar vortex has not yet been observed. On Earth, the polar vortex is nonlinearly disrupted by interaction with large-amplitude planetary waves. Large-scale waves have not been identified in Titan's atmosphere, so the decay of its polar vortex may be more gradual than on Earth. Observations from an extended Cassini mission into late northern spring should provide critical data indicating whether the vortex goes away with a bang or just fades away.

Flasar, F.M.; Achterberg, R.K.; Schinder, P.J.

2008-01-01

136

Editorial - The winter Atomiades  

CERN Document Server

As we wrote in our previous editorial, the Staff Association gives direct support to sports events, such as the Atomiades, a section of the Association of Sports Communities of European Research Institutes, which brings together sportsmen and women from 38 European research centres in 13 countries (Austria, Belgium, Czech Republic, United Kingdom, Finland, France, Germany, Hungary, Italy, Luxemburg, the Netherlands, Russia, and Switzerland). The summer Atomiades take place between the months of June and September every three years. Thirteen such events have taken place since 1973, the last one in June 2009 in Berlin. As far as the winter Atomiades are concerned, also organized every three years, and alternating with the summer Atomiades, there have been eleven since 1981, the last one at the end of January this year in neighbouring France. The following article tells the wonderful adventure of the CERN staff who took part in this event. A positive outcome for CERN skiers at the winter Atomiades The 11t...

Staff Association

2011-01-01

137

Winter Storm Activity  

Science.gov (United States)

This project explores factors that help create severe winter weather. An interactive simulation provides hands-on experience, followed by guiding questions and resource exploration. Form groups of three. Explore the following simulation: Weather Maker Simulator Use the simulation to answer the following questions on paper. 1. In general, when are winds formed? 2. When winds are blowing, how can you get them to stop? 3. What usually happens when there is a large difference between the temperatures? 4. What happens when there ...

Barbieri, Mikel

2012-02-13

138

[Suitability evaluation of great bustard (Otis tarda)'s wintering habitat in Baiyangdian basin].  

Science.gov (United States)

Based on the related researches of great bustard's wintering habitat selection as well as the advices of related experts and the distribution records of great bustard in Baiyangdian basin, 3 first class indices and 13 second indices were chosen to characterize the key factors affecting the wintering habitat selection of great bustard, and a habitat quality evaluation model was built to assess the quality of wintering habitat selection of great bustard in Baiyangdian basin. In 2005, the suitable wintering habitats of great bustard in the basin had an area of 11907.25 km2, accounting for 34.1% of the total. Of the suitable wintering habitats, the most suitable habitats had an area of 4596.25 km2, only 13.2% of the total and comparatively concentrated in two zones, i.e., Baiyangdian Wetland Natural Reserve and its peripheral area (zone I) in the east of Baiyangdian basin, and Xingtang and Quyang counties (zone II) in the southwest of Baiyangdian basin. The total area of the most suitable habitats in zone I and zone II was 2803.55 km2, accounting for 61.0% of the most suitable habitats in the basin. To protect the wintering habitat of great bustard in the basin, proper measures should be taken according to the environmental features of the two zones. PMID:22007472

Zhao, Zhi-xuan; Yan, Deng-hua; Weng, Bai-sha; Zhang, Biao

2011-07-01

139

Effects of temper condition and corrosion on the fatigue performance of a laser-welded Al-Cu-Mg-Ag (2139) alloy  

International Nuclear Information System (INIS)

The effects of temper condition and corrosion on the fatigue behavior of a laser beam welded Al-Cu-Mg-Ag alloy (2139) have been investigated. Natural aging (T3 temper) and artificial aging (T8 temper) have been applied prior to welding. Corrosion testing has been performed by exposing the welded specimens to a salt spray medium for 720 h. Aging influences the corrosion behavior of laser welds. In the T3 temper, corrosion attack is in the form of pitting in the weld area, while in the T8 temper corrosion is in the form of pitting and intergranular corrosion in the base metal. In the latter case corrosion is attributed to the presence of grain boundary precipitates. Corrosion degrades the fatigue behavior of 2139 welds. The degradation is equal for both the T3 and T8 tempers and for the corrosion exposure selected in this study corresponds to a 52% reduction in fatigue limit. In both cases fatigue crack initiation is associated with corrosion pits, which act as stress raisers. In the T3 temper, the fatigue crack initiation site is at the weld metal/heat affected zone interface, while for the T8 temper the initiation site is at the base metal. Fatigue crack initiation in uncorroded 2139 welds occurs at the weld toe at the root side, the weld reinforcement playing a principal role as stress concentration site. The fatigue crack propagates through the partially melted zone and the weld metal in all cases. The findings in this paper present useful information for the selection of appropriate heat treatment conditions, to facilitate control of the corrosion behavior in aluminium welds, which is of great significance for their fatigue performance.

140

AGEING AND TEMPERING OF FERROUS MARTENSITES  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The low temperature ageing of a Fe-15wt%Ni-1wt%C martensite (Ms temperature -35 C) has been investigated using field - ion microscopy and atom probe microanalytical techniques. It is demonstrated that both the amplitude and the wavelength of the carbon composition fluctuations observed during room-temperature ageing increase with time, indicating that the alloy decomposes by a spinodal process. The carbon-rich regions approach a limiting composition of Fe8C during this reaction. The tempering...

Chang, Li; Smith, G.; Olson, G.

1986-01-01

 
 
 
 
141

Grazing Management of Temperate Grasslands and Fallows  

Directory of Open Access Journals (Sweden)

Full Text Available The paper provides a general overview of fodder resources andtheir management in temperate Bhutan (altitude range of1500-3000m. The terms are used as defined by RC-Jakar(RNR-RC-Jakar, 1996. As per these definitions, temperatepasture can include any kind of land used for grazing. Whenreferring to registered grassland or tsamdro, only the termtsamdrog is used. Where possible, the term pasture isreplaced with more specific or more appropriate terms.

Walter Roder

2002-01-01

142

Leaf out phenology in temperate forests  

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Full Text Available Monitoring phenology, the study of the timing of natural events, is an ancient practice that has experienced renewed relevance for scientific research interest in the wake of awareness of anthropogenic climate change. Spring onset has been occurring significantly earlier in temperate regions worldwide. Leaf out phenology has become particularly well studied is of particular interest because the emergence of leaves in the spring is extremely sensitive to temperature, and the leaf out timing of leaf out in temperate ecosystems marks the onset of the growing season and controls many essential ecosystem processes. This article reviews the current literature concerning the different methods used to study leaf out phenology, the controls on leaf out in temperate woody plants, and the effects of climate change on leaf out phenology. In addition to the traditional method of on-the-ground leaf out monitoring, new methods using remote sensing and dedicated cameras have been developed which allow scientists to track spring onset at a much larger scale than hadpreviously been possible. Further work is needed on how leaf phenology will respond to future climate change, and the implications of this for animals and other species interactions among trophic levels.

Caroline A. Polgar

2013-01-01

143

Hydrology and morphology of two river mouth regions (temperate Vistula Delta and subtropical Red River Delta  

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Full Text Available The paper presents a comparative analysis of two different river mouths from two different geographical zones (subtropical and temperate climatic regions. One is the multi-branch and multi-spit mouth of the Red River on the Gulf of Tonkin (Vietnam, the other is the smaller delta of the river Vistula on a bay of the Baltic Sea (Poland. The analysis focuses on the similarities and differences in the hydrodynamics between these estuaries and the adjacent coastal zones, the features of sediment transport, and the long-term morphodynamics of the river outlets. Salinity and water level are also discussed, the latter also in the context of the anticipated global effect of accelerated sea level rise. The analysis shows that the climatic and environmental conditions associated with geographical zones give rise to fundamental differences in the generation and dynamic evolution of the river mouths.

Zbigniew Pruszak

2005-09-01

144

Temperature Dependency of Photosynthesis of Sphagnum spp. Distributed in the Warm-Temperate and the Cool-Temperate Mires of Japan  

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Full Text Available We investigated the temperature dependency of photosynthetic rates for five Sphagnum species: Sphagnum palustre, S. fimbriatum in the Tadewara mire (south-western Japan in a warm-temperate zone and S. papillosum, S. fuscum, S. fallax in the East Ochiishi mire (north-eastern Japan in a cool-temperate zone measuring photosynthetic light response within a temperature range between 5 and 40?C. The maximum photosynthetic rate was obtained at T = 35?C for S. palustre, S. fuscum and S. papillosum, and at T = 30?C for S. fimbriatum and S. fallax. Photosynthetic rates of all these species showed a maximum at 300 - 500 ?mol·m-2·s-1 of PPFD and it decreased at higher PPFD (>500 ?mol·m-2·s-1 under low temperature (5?C - 10?C. These results imply that Sphagnum species are not fully physiologically adapted to low temperature environments, although Sphagnum species distribute mostly in the circumpolar region.

Akira Haraguchi

2011-11-01

145

Soil respiration under snowpack in a temperate forest in Massachusetts: steady state vs. transient state  

Science.gov (United States)

Soil respiration plays a major role in global carbon cycling. However, the magnitude and process of soil respiration under snowpack is not well understood due to the difficulty in measuring soil respiration in temperate forests under snowpack through the winter. As a result, when the annual cumulative flux of soil respiration is estimated, soil respiration during the winter is either neglected or modeled solely from a temperature function that is derived from the growing season respiration measurement. The traditional chamber method does not work well on snowpack. The eddy covariance method in winter covers total ecosystem respiration that includes both aboveground plant respiration and belowground soil respiration. Here we used a belowground soil CO2 profile system to measure soil respiration under snowpack. The measurement system functioned when the forest floor was covered by snow. Three CO2 sensors were buried vertically, at different depths, in the soil to obtain a CO2 profile. The surface CO2 efflux was calculated based on Fick’s law of diffusion. The snowpack depth was also measured with an automated sonic ranging sensor. Under the steady state, the snowpack did not physically change the soil CO2 efflux, but it increased soil temperature and thus indirectly increased soil CO2 efflux. During the transient period (snowfall or melting), the snowpack changed soil CO2 efflux. The temperature sensitivity, Q10, was higher in the low temperature range than in the high temperature range in winter. Our results suggest that winter soil respiration is more complicated than non-snow covered seasons and should not be neglected in estimating the annual carbon budget.

Tang, J.

2010-12-01

146

Fallback foods of temperate-living primates: a case study on snub-nosed monkeys.  

Science.gov (United States)

Only a few primate species thrive in temperate regions characterized by relatively low temperature, low rainfall, low species diversity, high elevation, and especially an extended season of food scarcity during which they suffer from dietary stress. We present data of a case study of dietary strategies and fallback foods in snub-nosed monkeys (Rhinopithecus bieti) in the Samage Forest, Northwest Yunnan, PRC. The snub-nosed monkeys adjusted intake of plant food items corresponding with changes in the phenology of deciduous trees in the forest and specifically showed a strong preference for young leaves in spring. A non-plant food, lichens (Parmeliaceae), featured prominently in the diet throughout the year (annual representation in the diet was about 67%) and became the dominant food item in winter when palatable plant resources were scarce. Additional highly sought winter foods were frost-resistant fruits and winter buds of deciduous hardwoods. The snub-nosed monkeys' choice of lichens as a staple fallback food is likely because of their spatiotemporal consistency in occurrence, nutritional and energetic properties, and the ease with which they can be harvested. Using lichens is a way to mediate effects of seasonal dearth in palatable plant foods and ultimately a key survival strategy. The snub-nosed monkeys' fallback strategy affects various aspects of their biology, e.g., two- and three-dimensional range use and social organization. The higher abundance of lichens at higher altitudes explains the monkeys' tendency to occupy relatively high altitudes in winter despite the prevailing cold. As to social organization, the wide temporal and spatial availability of lichens strongly reduces the ecological costs of grouping, thus allowing for the formation of "super-groups." Usnea lichens, the snub-nosed monkeys' primary dietary component, are known to be highly susceptible to human-induced environmental changes such as air pollution, and a decline of this critical resource base could have devastating effects on the last remaining populations. Within the order Primates, lichenivory is a rare strategy and only found in a few species or populations inhabiting montane areas, i.e., Macaca sylvanus, Colobus angolensis, and Rhinopithecus roxellana. Other temperate-dwelling primates rely mainly on buds and bark as winter fallback foods. PMID:19890849

Grueter, Cyril C; Li, Dayong; Ren, Baoping; Wei, Fuwen; Xiang, Zuofu; van Schaik, Carel P

2009-12-01

147

The macroalgal carbonate factory at a cool-to-warm temperate marine transition, Southern Australia  

Science.gov (United States)

The shallow neritic seafloor to depths of ~ 30 m along the coast of southwestern Victoria Australia, is the site of rocky reefs on volcanic and aeolianite bathymetric highs. The region, located near the warm- to cool-temperate environmental transition, is a site of prolific macroalgae (kelp) growth. Kelps are most prolific and diverse in high-energy, open-ocean environments whereas broad-leafed seagrasses, at their cold-water eastern limit, are restricted to local protected embayments. The seagrasses are reduced to one species of Amphibolis whereas the kelps are diverse and include the large intertidal bull kelp (Durvillaea), not present in warmer waters. The macroalgal forest extends from the intertidal to ~ 30 mwd (metres water depth) as a series of distinct biomes; 1) the Peritidal, 2) the Phaeophyte Forest (0-17 mwd), 3) the Rhodophyte Thicket (17-15 mwd), and 4) the Invertebrate Coppice (> 25 mwd). The Phaeophyte Forest is partitioned into a Durvillaea zone (0-2 mwd), a Phyllospora zone (2-10 mwd) and an Ecklonia zone (10-17mwd). The two major habitats within each biome comprise 1) an upward facing illuminated surface that supports a macroalgal canopy over an understorey of coralline algae and herbivorous gastropods, and 2) a separate, cryptic, shaded habitat dominated by a diverse community of filter-feeding invertebrates. These communities produce two different sediments; 1) geniculate and encrusting corallines and diverse gastropods from the upper surface, and 2) bryozoans, molluscs, barnacles, chitons, serpulids, and benthic foraminifers from the shaded, cryptic habitats. These particles are blended together with the latter becoming proportionally more abundant with increasing depth. Results of this study, when integrated with recent investigations in warm-temperate (South Australia) and cool-temperate (New Zealand) environments now define carbonate sedimentology of the macroalgal reef depositional system in this part of the northern Southern Ocean.

James, Noel P.; Reid, Catherine M.; Bone, Yvonne; Levings, Andrew; Malcolm, Isabelle

2013-06-01

148

Seasonal ovulatory activity exists in tropical Creole female goats and Black Belly ewes subjected to a temperate photoperiod  

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Full Text Available Abstract Background Seasonality of ovulatory activity is observed in European sheep and goat breeds, whereas tropical breeds show almost continuous ovulatory activity. It is not known if these tropical breeds are sensitive or not to temperate photoperiod. This study was therefore designed to determine whether tropical Creole goats and Black-Belly ewes are sensitive to temperate photoperiod. Two groups of adult females in each species, either progeny or directly born from imported embryos, were used and maintained in light-proof rooms under simulated temperate (8 to 16 h of light per day or tropical (11 – 13 h photoperiods. Ovulatory activity was determined by blood progesterone assays for more than two years. The experiment lasted 33 months in goats and 25 months in ewes. Results Marked seasonality of ovulatory activity appeared in the temperate group of Creole female goats. The percentage of female goats experiencing at least one ovulation per month dramatically decreased from May to September for the three years (0%, 27% and 0%, respectively. Tropical female goats demonstrated much less seasonality, as the percentage of goats experiencing at least one ovulation per month never went below 56%. These differences were significant. Both groups of temperate and tropical Black-Belly ewes experienced a marked seasonality in their ovulatory activity, with only a slightly significant difference between groups. The percentage of ewes experiencing at least one ovulation per month dropped dramatically in April and rose again in August (tropical ewes or September (temperate ewes. The percentage of ewes experiencing at least one ovulation per month never went below 8% and 17% (for tropical and temperate ewes respectively during the spring and summer months. Conclusions An important seasonality in ovulatory activity of tropical Creole goats was observed when females were exposed to a simulated temperate photoperiod. An unexpected finding was that Black-Belly ewes and, to a lesser extent, Creole goats exposed to a simulated tropical photoperiod also showed seasonality in their ovulatory activity. Such results indicate that both species are capable of showing seasonality under the photoperiodic changes of the temperate zone even though they do not originate from these regions.

Aumont Gilles

2004-08-01

149

Control of weldability : Research leading to the development of two new quenched and tempered tool steels  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The understanding of the hardenability is important in steel development with respect to weldability of steels as well as to the design of quenched and tempered steels.The common way to judge if steel is suitability to welding is the use of a carbon equivalent, which reflects the alloy content to the hardenability of the heat affected zone (HAZ). Most common of these equivalent is the IIW carbon equivalent wich has been in use for decades. However, this is an empirical equivalent, developed f...

Hansson, Per

2004-01-01

150

Some Properties of Saturn'ian Equatorialand Temperate Belts at the 2009 Equinox  

Science.gov (United States)

The special processing was made for more than 600 zonal spectra obtained by scanning of Saturn’s disk during the equinox-2009. A comparative study of the optical characteristics of the southern and northern temperate latitudes and equatorial belt have shown some hemispheric differences in the methane absorption behavior. In the equatorial zone we have usually observed decrease in the intensity of the methane absorption compared to temperate latitudes. But the correct estimation of this difference may be done only at the equinox when the ting influence is minimal. In 2009 the methane absorption on equator leas 21-24 per cent less than on temperate latitudes and it may considered as true value of that difference. The CH4 absorption bands variations at middle latitudes show some of the specific features. In particular, the absorption band of 725 nm in the southern hemisphere is not different from that in the northern hemisphere. However, other bands, centered at 619, 678, 702 and 787 nm, ate some less in the S- hemisphere than in the N-hemisphere. This difference grows with the bands weakening. During the preceding equinox in 1995 similar asymmetry was expressed more strongly and also with the absorption depression at southern hemisphere. These differences are considered as related to the vertical inhomogeneity of the cloud layer, increased the upper boundary of the clouds in the equatorial belt, and seasonal changes in the radiation regime hemispheres of Saturn. The results of this work will be published in «Solar System Research».

Tejfel, Victor G.; Karimov, Alibek M.; Kharitonova, Galina A.

2014-11-01

151

Robust Parameter Selection for Parallel Tempering  

CERN Document Server

This paper describes an algorithm for selecting parameter values (e.g. temperature values) at which to measure equilibrium properties with Parallel Tempering Monte Carlo simulation. Simple approaches to choosing parameter values can lead to poor equilibration of the simulation, especially for Ising spin systems that undergo $1^st$-order phase transitions. However, starting from an initial set of parameter values, the careful, iterative respacing of these values based on results with the previous set of values greatly improves equilibration. Example spin systems presented here appear in the context of Quantum Monte Carlo.

Hamze, Firas; Karimi, Kamran

2010-01-01

152

Asymptotic hyperfunctions, tempered hyperfunctions, and asymptotic expansions  

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Full Text Available We introduce new subclasses of Fourier hyperfunctions of mixed type, satisfying polynomial growth conditions at infinity, and develop their sheaf and duality theory. We use Fourier transformation and duality to examine relations of these asymptotic and tempered hyperfunctions to known classes of test functions and distributions, especially the Gel'fand-Shilov spaces. Further it is shown that the asymptotic hyperfunctions, which decay faster than any negative power, are precisely the class that allows asymptotic expansions at infinity. These asymptotic expansions are carried over to the higher-dimensional case by applying the Radon transformation for hyperfunctions.

Andreas U. Schmidt

2005-05-01

153

A Winter's Tale  

Science.gov (United States)

This resource explores winter weather and frozen precipitation. The page on precipitation points out that snow and rain are both water and explains how the different forms of frozen precipitation (snow, sleet, freezing rain) occur. There is a page on cirrus clouds that explains their characterstics and how they may affect climate by reflecting solar radiation or reducing outgoing infrared energy from Earth. The Jet Stream page explains the characteristics of these high-speed rivers of air, including what causes them and their effect on weather and climate. There is also a feature on the esthetic wonders of frozen water, including halos produced by ice crystals in the air, sparkling of snowflakes, why fresh snow squeaks when stepped on, and why it is silent during a snowfall. A bibliography is also provided.

154

Winter fuels report  

International Nuclear Information System (INIS)

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and State and local governments on the following topics: distillate fuel oil net production, imports and stocks on a US level and for all Petroleum Administration for Defense Districts (PADD) and product supplied on a US level; propane net production, imports and stocks on a US level and for PADD's I, II, and III; natural gas supply and disposition and underground storage for the US and consumption for all PADD's, as well as selected National average prices; residential and wholesale pricing data for heating oil and propane for those States participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil and petroleum price comparisons for the US and selected cities; and a 6-10 day, 30-Day, and 90-Day outlook for temperature and precipitation and US total heating degree-days by city

155

Influenza-associated mortality in temperate and subtropical chinese cities, 2003-2008 / Mortalité associée à la grippe dans les villes des zones tempérées et subtropicales de Chine, 2003-2008 / La mortalidad asociada a la gripe en ciudades chinas con clima templado y subtropical, 2003-2008  

Scientific Electronic Library Online (English)

Full Text Available SciELO Public Health | Language: English Abstract in spanish OBJETIVO: Calcular la mortalidad asociada a la gripe en la China urbana. MÉTODOS: Se calculó el exceso de mortalidad asociado a la gripe durante el periodo comprendido entre 2003 y 2008 en tres ciudades del norte de China con clima templado y en cinco ciudades del sur del país con clima subtropical. [...] Los cálculos se obtuvieron de modelos basados en regresiones binomiales negativas, estadísticas vitales y de los resultados de la vigilancia semanal del virus de la gripe. RESULTADOS: El exceso de mortalidad anual asociado a la gripe, por todas las causas, fue de 18,0 (rango: 10,9-32,7) muertes por cada 100000 habitantes en las ciudades del norte y de 11,3 (rango: 7,3-17,8) muertes por cada 100000 habitantes en las ciudades del sur. La mayor parte de este exceso de mortalidad - 12,4 (rango: 7,4-22,2) y 8,8 (rango: 5,5-13,6) muertes por cada 100000 habitantes en las ciudades del norte y del sur, respectivamente - se atribuyeron a una enfermedad respiratoria y/o circulatoria. La mayoría de las muertes (el 86%) ocurrió en personas con una edad >65 años. El exceso de mortalidad asociado a la gripe fue superior en épocas con un virus B dominante que en épocas en las que predominaron los virus A(H3N2) o A(H1N1). Más de la mitad de la mortalidad total asociada a la gripe se asoció al virus B de la gripe. CONCLUSIÓN: Entre 2003 y 2008, la gripe estacional, particularmente la causada por el virus B de la gripe, estuvo asociada a la mortalidad sustancial en tres ciudades de China con clima templado y en cinco ciudades del sur del país con clima subtropical. Abstract in english OBJECTIVE: To estimate influenza-associated mortality in urban China. METHODS: Influenza-associated excess mortality for the period 2003-2008 was estimated in three cities in temperate northern China and five cities in the subtropical south of the country. The estimates were derived from models base [...] d on negative binomial regressions, vital statistics and the results of weekly influenza virus surveillance. FINDINGS: Annual influenza-associated excess mortality, for all causes, was 18.0 (range: 10.9-32.7) deaths per 100000 population in the northern cities and 11.3 (range: 7.3-17.8) deaths per 100000 in the southern cities. Excess mortality for respiratory and circulatory disease was 12.4 (range: 7.4-22.2) and 8.8 (range: 5.5-13.6) deaths per 100000 people in the northern and southern cities, respectively. Most (86%) deaths occurred among people aged >65 years. Influenza-associated excess mortality was higher in B-virus-dominant seasons than in seasons when A(H3N2) or A(H1N1) predominated, and more than half of all influenza-associated mortality was associated with influenza B virus. CONCLUSION: Between 2003 and 2008, seasonal influenza, particularly that caused by the influenza B virus, was associated with substantial mortality in three cities in the temperate north of China and five cities in the subtropical south of the country.

Luzhao, Feng; David K, Shay; Yong, Jiang; Hong, Zhou; Xin, Chen; Yingdong, Zheng; Lili, Jiang; Qingjun, Zhang; Hong, Lin; Shaojie, Wang; Yanyan, Ying; Yanjun, Xu; Nanda, Wang; Zijian, Feng; Cecile, Viboud; Weizhong, Yang; Hongjie, Yu.

2012-04-01

156

Adhesion and wear properties of boro-tempered ductile iron  

International Nuclear Information System (INIS)

Highlights: ? In this study, the wear and adhesion properties of BDI were investigated. ? Boro-tempering process under several heat treatment conditions was examined. ? Optical microscope, SEM and XRD analysis were carried out to investigate the microstructure. ? It was observed that boro-tempering process improves micro-hardness and wear properties of ductile irons. -- Abstract: In this study, adhesion and wear properties of boro-tempered ductile iron (BDI) were investigated. Boro-tempering was carried out on two stage processes i.e. boronizing and tempering. At the first stage, ductile iron samples were boronized by using pack process at 900 oC for 1, 3, and 5 h and then, secondly tempered at 250, 300, 350, and 400 oC for 1 h. X-ray diffraction (XRD) analysis of boro-tempered samples showed that FeB and Fe2B phases were found on the surface of the samples. The Daimler-Benz Rockwell-C adhesion test was used to assess the adhesion of boride layer. Test result showed that adhesion decreased with increasing boriding time and increased with increasing tempering temperature. Dry sliding wear tests of these samples were performed against Al2O3 ball at a constant sliding speed and loads of 5 and 10 N. Wear tests indicated that boro-tempering heat treatment increased wear resistance of ductile iron. In addition, it was found that while wear rate of boro-tempered samples decreased with increasing boriding time, there is no significant affect of tempering temperature on wear rate.

157

Solar energy reflector for steel tempering  

International Nuclear Information System (INIS)

Solar energy is a vital source of energy. It attracted the attention of many nations. In fact two aspects promote the use of solar energy specially for the low temperature heat treatment of metal: 1- Environmental protection. 2- Economical issue. The search for the implementation of solar energy as a source remains a key issue in widening the scope of solar energy application and use in industry. This paper is an attempt to explore the feasibility and efficiency of using solar reflector in the tempering treatment of steel. A solar reflector in constructed, basically by a rolled steel plate with glass mirror strips glued to the rolled steel plate. A heating chamber is constructed at the focal site of the parabola in which small steel specimens were placed and then under the effect of solar sun shine the temperature of the specimens raise and for a period of time they were subjected to tempering. The temperature in the chamber was monitored and it was found that it reaches 110 degree centigrade in the months July and August just past middy 12:35.(Author)

158

A case of congenital plasmodium vivax malaria from a temperate region in central china  

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Full Text Available Abstract In February 2011, a rare case of congenital Plasmodium vivax malaria was diagnosed in a temperate region of Central China. An infant developed intermittent fever 20?days after delivery. Since this occurred during the non-transmission winter season in a low malaria endemic region and the infant’s mother did not have a clear malaria history or showed malaria symptoms at the time of the delivery, malaria infection was not suspected at the beginning. Later, on suspicion of potential malignant haematological illness due to persistence of the fever, bone marrow smear was examined, which revealed infection by P. vivax parasite. This rare case of congenital vivax malaria underlines that malaria diagnosis might need to be included in the healthcare of neonates born in vivax-endemic areas.

Liu Xue

2012-06-01

159

Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere  

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Full Text Available Dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH cartridges and high performance liquid chromatography (HPLC, optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in late summer (February–March over the Chatham Rise in the South West Pacific Ocean during the Surface Ocean Aerosol Production (SOAP voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in late winter (August–September 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim, and 24 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 12 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent MAX-DOAS observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but 14 molecules cm?2 at both sites. This discrepancy may be due to the incorrect assumption that all glyoxal observed by satellite is within the boundary layer, or may be due to challenges retrieving low VCDs of glyoxal over the oceans due to interferences by liquid water absorption, or use of an inappropriate normalisation reference value in the retrieval algorithm. This study provides much needed data to verify the presence of these short lived gases over the remote ocean and provide further evidence of an as yet unidentified source of both glyoxal and also methylglyoxal over the remote oceans.

S. J. Lawson

2014-08-01

160

High order schemes for the tempered fractional diffusion equations  

CERN Document Server

L\\'{e}vy flight models whose jumps have infinite moments are mathematically used to describe the superdiffusion in complex systems. Exponentially tempering the probability of large jumps of L\\'{e}vy flights leads to the tempered stable L\\'{e}vy processes which combine both the $\\alpha$-stable and Gaussian trends; and the very large jumps are unlikely and all their moments exist. The probability density functions of the tempered stable L\\'{e}vy processes solve the tempered fractional diffusion equation. This paper focuses on designing the high order difference schemes for the tempered fractional diffusion equation on bounded domain. The high order difference approximations, called the tempered and weighted and shifted Gr\\"{u}nwald difference (tempered-WSGD) operators, in space are obtained by using the properties of the tempered fractional calculus and weighting and shifting their first order Gr\\"{u}nwald type difference approximations. And the Crank-Nicolson discretization is used in the time direction. The s...

Li, Can

2014-01-01

 
 
 
 
161

Tempering characteristics of a vanadium containing dual phase steel  

Science.gov (United States)

Dual phase steels are characterized by a microstructure consisting of ferrite, martensite, retained austenite, and/or lower bainite. This microstructure can be altered by tempering with accompanying changes in mechanical properties. This paper examines such changes produced in a vanadium bearing dual phase steel upon tempering below 500 °C. The steel mechanical properties were minimally affected on tempering below 200 °C; however, a simultaneous reduction in uniform elongation and tensile strength occurred upon tempering above 400 °C. The large amount of retained austenite (?10 vol pct) observed in the as-received steel was found to be essentially stable to tempering below 300 °C. On tempering above 400 °C, most of the retained austenite decomposed to either upper bainite (at 400 °C) or a mixture of upper bainite and ferrite-carbide aggregate formed by an interphase precipitation mechanism (at 500 °C). In addition, tempering at 400 °C led to fine precipitation in the retained ferrite. The observed mechanical properties were correlated with these microstructural changes. It was concluded that the observed decrease in uniform elongation upon tempering above 400 °C is primarily the consequence of the decomposition of retained austenite and the resulting loss of transformation induced plasticity (TRIP) as a contributing mechanism to the strain hardening of the steel.

Rashid, M. S.; Rao, B. V. N.

1982-10-01

162

Simulated-tempering approach to spin-glass simulations  

Digital Repository Infrastructure Vision for European Research (DRIVER)

After developing an appropriate iteration procedure for the determination of the parameters, the method of simulated tempering has been successfully applied to the 2D Ising spin glass. The reduction of the slowing down is comparable to that of the multicanonical algorithm. Simulated tempering has, however, the advantages to allow full vectorization of the programs and to provide the canonical ensemble directly.

Kerler, Werner; Rehberg, Peter

1994-01-01

163

On the transgranular type of tempered martensite embrittlement  

International Nuclear Information System (INIS)

Martensitic alloy steels are subject to tempering because of their low toughness in the as-quenched state. When tempered in the range of 250--400 C, however, the toughness drops in spite of the decrease in strength with increasing the tempering temperature. This phenomenon is referred to as tempered martensite embrittlement (TME). TME can be classified into two types according to the fracture mode; intergranular and transgranular TME. The transgranular type was suggested to be caused by the formation of coarse carbides at the lath boundaries following the decomposition of retained austenite. In this study, the transgranular type of TME has been analyzed in terms of impact toughness, fracture behavior and microstructure on isothermal tempering. The experimental alloy systems chosen are the Mo and MoW steels in which alloying elements, Mo and W, may decrease the intrinsic toughness and thus produce easy transgranular brittle fracture

164

Estimativa de horas de frio abaixo de 7 e de 13°C para regionalização da fruticultura de clima temperado no estado de São Paulo Temperate fruit crop zoning in the State of São Paulo - Brazil based upon estimated number of hours with temperature below 7 and 13°C  

Directory of Open Access Journals (Sweden)

Full Text Available Estimativa e mapeamento do número de horas com temperaturas abaixo de 7 e 13°C no Estado de São Paulo e análise comparativa do comportamento de fruteiras de clima temperado constituem os objetivos do presente trabalho. Foi cotado o número de horas com temperaturas inferiores a 7 e 13°C, índices considerados limites necessários à dormência dessas plantas. Foram selecionados termogramas de doze postos agrometeorológicos do Instituto Agronômico, situados em altitudes variáveis entre 25 e 1.000m, correspondentes ao per?odo 1964-1973. Estabeleceram-se equações para estimativa do número de horas com temperaturas inferiores a 7°C (HF-7 e 13°C (HF-13 em função da temperatura m?dia do mês de julho, cujos coeficientes de correlação foram de -0,88 e -0,93, respectivamente. Com base nessas equações foram mapeadas as isolinhas de HF-7 e HF-13 para o Estado de São Paulo, encontrando-se desde valores médios anuais de HF-7 inferiores a 20 horas, característicos das regiões de transi??o de clima mesotérmico a megatérmico do Planalto Ocidental e das regiões mais baixas do norte e oeste do Estado, at? valores anuais de HF-7 superiores a 200 horas, característicos das áreas acima de 1.500 metros de altitude no Sul do Estado, na serra da Mantiqueira, limítrofe com Minas Gerais, e na serra do Mar, limítrofe com o Rio de Janeiro. Com base na introdu??o de diferentes frutíferas de clima temperado no Estado de São Paulo, verificou-se uma relação muito grande entre os índices HF-7 e HF-13 mapeados com o comportamento e potencialidade de exploração comercial.The behavior of temperate climate fruit crops in the State of São Paulo - Brazil as function of "dormancy units" (DAMARIO, 1969 was analysed with the object of providing a simple method for mapping areas with aptitude for commercial development of the crop trees. Thermographs from 12 agrometeorological stations located at altitudes varying from 25 to 1000 meters above sea level and corresponding to the period 1964-1973 were analysed. The number of hours with temperatures below 7 and 13°C, obtained from the diagrams, were correlated with the mean temperature of July, the coldest month, with correlation coeficients equal to -0.88 and -0.93, respectively. Regression equations, were used for mapping the isolines of "dormancy units" for both base temperatures. It was shown that the total period with temperature below 7°C is variable from 20 to more than 200 hours as the altitude increases. A good agreement between commercial exploitation of the crops and the chilling period was also observed.

Mário J. Pedro Júnior

1979-01-01

165

Estimativa de horas de frio abaixo de 7 e de 13°C para regionalização da fruticultura de clima temperado no estado de São Paulo / Temperate fruit crop zoning in the State of São Paulo - Brazil based upon estimated number of hours with temperature below 7 and 13°C  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Estimativa e mapeamento do número de horas com temperaturas abaixo de 7 e 13°C no Estado de São Paulo e análise comparativa do comportamento de fruteiras de clima temperado constituem os objetivos do presente trabalho. Foi cotado o número de horas com temperaturas inferiores a 7 e 13°C, índices cons [...] iderados limites necessários à dormência dessas plantas. Foram selecionados termogramas de doze postos agrometeorológicos do Instituto Agronômico, situados em altitudes variáveis entre 25 e 1.000m, correspondentes ao período 1964-1973. Estabeleceram-se equações para estimativa do número de horas com temperaturas inferiores a 7°C (HF-7) e 13°C (HF-13) em função da temperatura média do mês de julho, cujos coeficientes de correlação foram de -0,88 e -0,93, respectivamente. Com base nessas equações foram mapeadas as isolinhas de HF-7 e HF-13 para o Estado de São Paulo, encontrando-se desde valores médios anuais de HF-7 inferiores a 20 horas, característicos das regiões de transição de clima mesotérmico a megatérmico do Planalto Ocidental e das regiões mais baixas do norte e oeste do Estado, até valores anuais de HF-7 superiores a 200 horas, característicos das áreas acima de 1.500 metros de altitude no Sul do Estado, na serra da Mantiqueira, limítrofe com Minas Gerais, e na serra do Mar, limítrofe com o Rio de Janeiro. Com base na introdução de diferentes frutíferas de clima temperado no Estado de São Paulo, verificou-se uma relação muito grande entre os índices HF-7 e HF-13 mapeados com o comportamento e potencialidade de exploração comercial. Abstract in english The behavior of temperate climate fruit crops in the State of São Paulo - Brazil as function of "dormancy units" (DAMARIO, 1969) was analysed with the object of providing a simple method for mapping areas with aptitude for commercial development of the crop trees. Thermographs from 12 agrometeorolog [...] ical stations located at altitudes varying from 25 to 1000 meters above sea level and corresponding to the period 1964-1973 were analysed. The number of hours with temperatures below 7 and 13°C, obtained from the diagrams, were correlated with the mean temperature of July, the coldest month, with correlation coeficients equal to -0.88 and -0.93, respectively. Regression equations, were used for mapping the isolines of "dormancy units" for both base temperatures. It was shown that the total period with temperature below 7°C is variable from 20 to more than 200 hours as the altitude increases. A good agreement between commercial exploitation of the crops and the chilling period was also observed.

Mário J., Pedro Júnior; Altino Aldo, Ortolani; Orlando, Rigitano; Rogério Remo, Alfonsi; Hilton Silveira, Pinto; Orivaldo, Brunini.

166

Effect of cohesive energy on thermal expansion behavior of T6 tempered 7A09 aluminum alloy  

International Nuclear Information System (INIS)

Highlights: ? Transformation related to ?’ and ? can cause cohesive energy and volume changes. ? These changes can influence the variation trend of CTE for 7A09 alloy. ? Cohesive energy change becomes a main factor influencing CTE from Ostwald ripening stage. - Abstract: The dynamic effect of cohesive energy on the CTE of T6 (the highest strength temper) tempered 7A09 aluminum alloy was studied in this paper. Transmission electron microscopy (TEM) was combined with differential scanning calorimetry (DSC) to analyze the phase transitions of T6 tempered 7A09 aluminum alloy taking place in a heating process. The corresponding CTE curve was recorded by a thermal dilatometer. The ion-bonding model was utilized to estimate the variation of cohesive energy caused by the phase transitions. Results indicate that GPII zones and ?? phase are main precipitates in T6 tempered 7A09 alloy. During the heating process, the cohesive energy of alloy system increases with the transition from ?? to ? phase and the precipitation of ? phase. The dissolution of ? phase leads to a decrease of cohesive energy. Although volume changes of alloy system have effects on the CTE, the effect of the cohesive energy change is more obvious than that of volume change after the precipitation of ? phase begins in the Ostwald ripening stage. Effects of cohesive energy and volume changes can be expressed in the nonlinearity of CTE curve.

167

Climatic records over the past 30 ka from temperate Australia - a synthesis from the Oz-INTIMATE workgroup  

Science.gov (United States)

Temperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30 ka. During the early glacial period (˜30-22 ka) and the Last Glacial Maximum (˜22-18 ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important Murray-Darling Basin. The temperate region at this time appears to be dominated by expanded sea ice in the Southern Ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast (including Tasmania) and southwest Australian coasts. The deglacial period (˜18-12 ka) was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records, while there is some evidence for climatic reversals (e.g. the Antarctic Cold Reversal) in high resolution marine sediment cores through this period. The high spatial density of Holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after ˜12 ka, presumably in response to increasing temperature, while hydrological records reveal spatially heterogeneous hydro-climatic trends. Patterns after ˜6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the El Niño/Southern Oscillation.

Petherick, L.; Bostock, H.; Cohen, T. J.; Fitzsimmons, K.; Tibby, J.; Fletcher, M.-S.; Moss, P.; Reeves, J.; Mooney, S.; Barrows, T.; Kemp, J.; Jansen, J.; Nanson, G.; Dosseto, A.

2013-08-01

168

Migration ecology of juvenile temperate seabass Lateolabrax japonicus: a carbon stable-isotope approach.  

Science.gov (United States)

The migration pattern of juvenile temperate seabass Lateolabrax japonicus in the stratified estuary of the Yura River was examined using carbon stable-isotope ratios (?(13)C). ?(13)C values of mysids, which are the most important prey items for this species, were consistently enriched in the lower estuary and surf zone (LES), while depleted in the freshwater zone (FW). ?(13)C values of juveniles in LES were enriched, while those in FW were depleted, consistent with the ?(13)C difference in prey items. The results of ?(13)C showed that many juveniles migrated upstream from April to June and most of them stayed in FW until at least July. Juveniles that stayed in FW and LES for a relatively longer period (> c. 20 days) showed higher condition factors than those that stayed in FW for a short period (several days). This indicates that residence in FW enabled juveniles to achieve as good a body condition as residence in LES. PMID:21651547

Fuji, T; Kasai, A; Suzuki, K W; Ueno, M; Yamashita, Y

2011-06-01

169

Winter fuels report  

Energy Technology Data Exchange (ETDEWEB)

The Winter Fuels Report is intended to provide concise, timely information to the industry, the press, policymakers, consumers, analysts, and state and local governments on the following topics: distillate fuel oil net production, imports and stocks for all PADD's and product supplied on a US level; propane net production, imports and stocks for Petroleum Administration for Defense Districts (PADD) I, II, and III; natural gas supply and disposition, underground storage, and consumption for all PADD's; residential and wholesale pricing data for propane and heating oil for those states participating in the joint Energy Information Administration (EIA)/State Heating Oil and Propane Program; crude oil price comparisons for the United States and selected cities; and US total heating degree-days by city. This report will be published weekly by the EIA starting the first week in October 1990 and will continue until the first week in April 1991. The data will also be available electronically after 5:00 p.m. on Thursday during the heating season through the EIA Electronic Publication System (EPUB). 12 tabs.

1990-10-04

170

Four-year measurement of methane flux over a temperate forest with a relaxed eddy accumulation method  

Science.gov (United States)

Forests are generally assumed to be an atmospheric methane (CH4) sink (Le Mer and Roger, 2001). However, under Asian monsoon climate, forests are subject to wide spatiotemporal range in soil water status, where forest soils often became water-saturated condition heterogeneously. In such warm and humid conditions, forests may act as a CH4 source and/or sink with considerable spatiotemporal variations. Micrometeorological methods such as eddy covariance (EC) method continuously measure spatially-representative flux at a canopy scale without artificial disturbance. In this study, we measured CH4 fluxes over a temperate forest during four-year period using a CH4 analyzer based on tunable diode laser spectroscopy detection with a relaxed eddy accumulation (REA) method (Hamotani et al., 1996, 2001). We revealed the amplitude and seasonal variations of canopy-scale CH4 fluxes. The REA method is the attractive alternative to the EC method to measure trace-gas flux because it allows the use of analyzers with an optimal integration time. We also conducted continuous chamber measurements on forest floor to reveal spatial variations in soil CH4 fluxes and its controlling processes. The observations were made in an evergreen coniferous forest in central Japan. The site has a warm temperate monsoon climate with wet summer. Some wetlands were located in riparian zones along streams within the flux footprint area. For the REA method, the sonic anemometer (SAT-550, Kaijo) was mounted on top of the 29-m-tall tower and air was sampled from just below the sonic anemometer to reservoirs according to the direction of vertical wind velocity (w). After accumulating air for 30 minutes, the air in the reservoirs was pulled into a CO2/H2O gas analyzer (LI-840, Li-Cor) and a CH4 analyzer (FMA-200, Los Gatos Research). Before entering the analyzers, the sampled air was dried using a gas dryer (PD-50 T-48; Perma Pure Inc.). The REA flux is obtained from the difference in the mean concentrations of the reservoirs. In the chamber method, automated dynamic-closed chambers were located at three points of water-unsaturated forest floor. Soil CO2 and CH4 fluxes were measured using the same analyzers with the REA method. CH4 fluxes showed seasonal variations at both canopy and plot scales. Based on the chamber measurements, water-unsaturated forest floor mostly consumed CH4 throughout a year. In contrast, canopy-scale CH4 fluxes by the REA method seasonally fluctuated between emission and absorption. The seasonal variation of canopy-scale CH4 fluxes varied at years to years. Every year, no notable emission nor absorption was observed during winter when daily average air temperature was less than about 10°C. In this forest, the canopy-scale CH4 fluxes could be determined by a balance between sources by methanogens and sinks by methanotrophs. Since these two processes were influenced by soil conditions (e.g., soil temperature and soil moisture), canopy-scale CH4 fluxes were influenced by CH4 fluxes from wetlands within the forest, because magnitude of wetland emission was a few order larger than those of absorption. We will discuss the factors of interannual variation of the canopy- and plot-scale CH4 fluxes in terms of precipitation patterns.

Sakabe, A.; Kosugi, Y.; Ueyama, M.; Hamotani, K.; Takahashi, K.; Iwata, H.; Itoh, M.

2013-12-01

171

Parallel tempering Monte Carlo in LAMMPS.  

Energy Technology Data Exchange (ETDEWEB)

We present here the details of the implementation of the parallel tempering Monte Carlo technique into a LAMMPS, a heavily used massively parallel molecular dynamics code at Sandia. This technique allows for many replicas of a system to be run at different simulation temperatures. At various points in the simulation, configurations can be swapped between different temperature environments and then continued. This allows for large regions of energy space to be sampled very quickly, and allows for minimum energy configurations to emerge in very complex systems, such as large biomolecular systems. By including this algorithm into an existing code, we immediately gain all of the previous work that had been put into LAMMPS, and allow this technique to quickly be available to the entire Sandia and international LAMMPS community. Finally, we present an example of this code applied to folding a small protein.

Rintoul, Mark Daniel; Plimpton, Steven James; Sears, Mark P.

2003-11-01

172

Temperate Ice Depth-Sounding Radar  

Science.gov (United States)

Glaciers in several parts of the world are reported to be retreating and thinning rapidly over the last decade. Radar instruments can be used to provide a wealth of information regarding the internal and basal conditions of large and small ice masses. These instruments typically operate in the VHF and UHF regions of the electromagnetic spectrum. For temperate-ice sounding, however, the high water content produces scattering and attenuation in propagating radar waves at VHF and UHF frequencies, which significantly reduce the penetration depths. Radars operating in the HF band are better suited for systematic surveys of the thickness and sub-glacial topography of temperate-ice regions. We are developing a dual-frequency Temperate-Ice-Depth Sounding Radar (TIDSoR) that can penetrate through water pockets, thus providing more accurate measurements of temperate ice properties such as thickness and basal conditions. The radar is a light-weight, low power consumption portable system for surface-based observations in mountainous terrain or aerial surveys. TIDSoR operates at two different center frequencies: 7.7 MHz and 14 MHz, with a maximum output peak power of 20 W. The transmit waveform is a digitally generated linear frequency-modulated chirp with 1 MHz bandwidth. The radar can be installed on aircrafts such as the CReSIS UAV [1], DCH-6 (Twin Otter), or P-3 Orion for aerial surveys, where it could be supported by the airplane power system. For surface based experiments, TIDSoR can operate in a backpack configuration powered by a compact battery system. The system can also be installed on a sled towed by a motorized vehicle, in which case the power supply can be replaced by a diesel generator. The radar consists of three functional blocks: the digital section, the radio-frequency (RF) section, and the antenna, and is designed to weigh less than 2 kg, excluding the power supply. The digital section generates the transmit waveforms as well as timing and control signals. It also digitizes the output signal from the receiver and stores the data in binary format using a portable computer. The RF-section consists of a high- power transmitter and a low-noise receiver with digitally controlled variable gain. The antenna is time-shared between the transmitter and receiver by means of a transmit/receive (T/R) switch. In regards to the antenna, we have made a survey study of various electrically small antennas (ESA) to choose the most suitable radiating structure for this application. Among the different alternatives that provide a good trade-off between electrical performance and small size, we have adopted an ESA dipole configuration for airborne platforms and a half-wavelength radiator for the surface-based version. The airborne antenna solution is given after studying the geometry of the aerial vehicle and its fuselage contribution to the antenna radiation pattern. Dipoles are made of 11.6 mm diameter cables (AWG 0000) or printed patches embedded into the aircraft fuselage, wings, or both. The system is currently being integrated and tested. TIDSoR is expected to be deployed during the spring 2008 either in Alaska or Greenland for surface based observations. In this paper, we will discuss our design considerations and current progress towards the development of this radar system. [1] Center for Remote Sensing of Ice Sheets (Cresis), Sept 2008, [Online]. Available: http://www.cresis.ku.edu

Jara-Olivares, V. A.; Player, K.; Rodriguez-Morales, F.; Gogineni, P.

2008-12-01

173

77 FR 60649 - Fisheries of the Exclusive Economic Zone Off Alaska; Pollock in the Herring Savings Areas of the...  

Science.gov (United States)

...Zone Off Alaska; Pollock in the Herring Savings Areas of the Bering Sea and Aleutian Islands...using trawl gear in the Winter Herring Savings Area of the Bering Sea and Aleutian Islands...using trawl gear in the Winter Herring Savings Areas of the BSAI. The Winter...

2012-10-04

174

Numerical investigation of a novel connection in tempered glass using holes drilled after tempering  

DEFF Research Database (Denmark)

This paper is a continuation of a previous paper [Nielsen, 2012] where the influ-ence on the temper stresses by drilling into tempered glass was investigated. In [Nielsen, 2012] it was shown that partly drilled holes in tempered glass would lead to higher compressive resid-ual hoop stresses at the hole increasing the apparent strength. Utilizing this for joints, raises new questions like the concentration of stresses arising at the hole for external loading of the pin and the glass. The present paper numerically investigates the shear load transfer for a specific configuration of the pin, the hole and the adhesive. In the paper a short discussion of the change in residual stresses due to the drilling and a FE-model for the loading of the pin in the hole is developed. From this model, the stress state occurring in such joints is investigated assuming both elastic and ideal plastic behaviour of the adhesive. Based on the numerical results, a proposal for an op-timal configuration using multiple pins is given.

Nielsen, Jens Henrik

2013-01-01

175

Seasonal in situ observations of glyoxal and methylglyoxal over the temperate oceans of the Southern Hemisphere  

Science.gov (United States)

Dicarbonyls glyoxal and methylglyoxal have been measured with 2,4-dinitrophenylhydrazine (2,4-DNPH) cartridges and high performance liquid chromatography (HPLC), optimised for dicarbonyl detection, in clean marine air over the temperate Southern Hemisphere (SH) oceans. Measurements of a range of dicarbonyl precursors (volatile organic compounds, VOCs) were made in parallel. These are the first in situ measurements of glyoxal and methylglyoxal over the remote temperate oceans. Six 24 h samples were collected in late summer (February-March) over the Chatham Rise in the South West Pacific Ocean during the Surface Ocean Aerosol Production (SOAP) voyage in 2012, while 34 24 h samples were collected at Cape Grim Baseline Air Pollution Station in late winter (August-September) 2011. Average glyoxal mixing ratios in clean marine air were 7 ppt at Cape Grim, and 24 ppt over Chatham Rise. Average methylglyoxal mixing ratios in clean marine air were 28 ppt at Cape Grim and 12 ppt over Chatham Rise. The mixing ratios of glyoxal at Cape Grim are the lowest observed over the remote oceans, while mixing ratios over Chatham Rise are in good agreement with other temperate and tropical observations, including concurrent MAX-DOAS observations. Methylglyoxal mixing ratios at both sites are comparable to the only other marine methylglyoxal observations available over the tropical Northern Hemisphere (NH) ocean. Ratios of glyoxal : methylglyoxal > 1 over Chatham Rise but site. Dicarbonyl precursor VOCs, including isoprene and monoterpenes, are used to calculate an upper estimate yield of glyoxal and methylglyoxal in the remote marine boundary layer and explain at most 1-3 ppt of dicarbonyls observed, corresponding to 11 and 17% of the observed glyoxal and 28 and 10% of the methylglyoxal at Chatham Rise and Cape Grim, respectively, highlighting a significant but as yet unknown production mechanism. Glyoxal surface observations from both sites were converted to vertical columns and compared to average vertical column densities (VCDs) from GOME-2 satellite retrievals. Both satellite columns and in situ observations are higher in summer than winter, however satellite vertical column densities exceeded the surface observations by more than 1.5 × 1014 molecules cm-2 at both sites. This discrepancy may be due to the incorrect assumption that all glyoxal observed by satellite is within the boundary layer, or may be due to challenges retrieving low VCDs of glyoxal over the oceans due to interferences by liquid water absorption, or use of an inappropriate normalisation reference value in the retrieval algorithm. This study provides much needed data to verify the presence of these short lived gases over the remote ocean and provide further evidence of an as yet unidentified source of both glyoxal and also methylglyoxal over the remote oceans.

Lawson, S. J.; Selleck, P. W.; Galbally, I. E.; Keywood, M. D.; Harvey, M. J.; Lerot, C.; Helmig, D.; Ristovski, Z.

2014-08-01

176

Winter, Your Car, and You  

Science.gov (United States)

... channel, or forecasts in the daily papers. Your Car Prepare your car for winter. Start with a checkup that includes: • ... Checking antifreeze level and the freeze line. Your car should have a tune-up (check the owner's ...

177

Winter in Hellas Basin  

Science.gov (United States)

[figure removed for brevity, see original site] Right now on Mars it is winter in the southern hemisphere. This means that the usually cloudy Hellas Basin is relatively free from clouds. Even though there is little cloud cover, the atmosphere is still much thicker due to the deeper basin compared to elsewhere on Mars, making image details not as crisp as when viewed through thinner atmosphere. In the center of the image are several dark streaks which originate from the side of a higher standing butte. The dark material is likely being eroded from a single layer within the cliff face. Wind has moved some of the eroded dark material to form the streaks.Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

2002-01-01

178

ACHIEVEMENTS IF WINTER PEA BREEDING ?????????? ? ???????? ????????? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available Winter pea is being bred at Krasnodar in the Research Institute of Agriculture of the Russian Academy of Agricultural Sciences. An alternative pea variety Legion has been bred and included into the National List of Varieties. The article presents the description of the first winter leafless pea varieties - Zimus and Fokus, which have been passed to the National Variety Testing System in 2011

Brezhneva V. I.

2012-04-01

179

Magnetic nondestructive technology for detection of tempered martensite embrittlement  

International Nuclear Information System (INIS)

A nondestructive eddy current technique is used to evaluate tempered martensite embrittlement in 4340 AISI steels after quench and tempering in the range 240–550 °C. A relation between the responses of the magnetic induction (normalized impedance of the coil) and destructive Charpy impact test results has been established. The study shows that the eddy current method could be used to separate brittle parts due to the microstructure changes. - Highlights: ? Occurrence of tempered martensite embrittlement in 4340 AISI steels was evaluated. ? A reliable relation between EC output and Charpy impact test results was obtained. ? EC technique was used to separate brittle parts due to the microstructure changes.

180

Non destructive evaluation of temper embrittlement of martensitic stainless steel  

International Nuclear Information System (INIS)

Martensitic stainless steel SS403, a sub set of SS410, is widely used as fuel-channel end-fitting material in Pressurized Heavy Water Reactor (PHWR). This material is selected because of its high corrosion resistance (the design utilizes several critical seal faces), good mechanical properties (optimum combination of strength, toughness and hardness for leak- tight roll joint), matching thermal coefficient of expansion with zirconium alloys (to minimize thermal stresses at rolled joint) and resistance to irradiation induced damages .The steel is produced by the electric arc furnace process and is subjected to vacuum degassing and electro-slag refining (ESR). The material is used in quenched and tempered condition. The end product should have at least 27 J minimum (Longitudinal) Charpy V-Notch (CVN) impact value at 21 deg C and 20J minimum (Transverse) CVN impact value at 65 deg C. In Martensitic Stainless Steel, a wide range of mechanical properties can be obtained by varying the tempering temperature and time . As tempering temperature is increased or time at particular temperature is prolonged, tensile strength, yield strength and hardness decrease; and impact strength, elongation, and reduction in area increase. The most uniform hardness is attained by close control of temperature, especially when tempering at lower temperatures. The tempering temperature depends primarily on the properties desired. Like most alloy steels, the hardenable stainless steels also develthe hardenable stainless steels also develop lower impact strength when tempered in the range from about 250 deg C to 550 deg C. Tempering at lower side of the range results in tempered martensite embrittlement (TME) whereas aging at temperature near 450-550 deg C results in temper embrittlement (TE). Temper embrittlement is caused by segregation of impurity elements mainly S, P. Si, Sn, As, Sb, and P at prior austenite grain boundaries. Under loading it causes de-cohesion along the grain boundaries leading to intergranular failure. Whereas TME is not related to the segregation phenomena and failure is transgranular with respect to prior austenite grain boundary. Magnitude of embrittlement is significantly greater in material which contain higher amount of retained austenite. Explanations of TME are linked to the coarsening of inter-lath cementite formed from decomposition of retained austenite during tempering. The embrittlement manifests as degradation in CVN impact properties namely viz, reduction in upper shelf energy (USE) or increase in ductile-brittle transition temperature (DBTT). As a result, tempering of this steel is generally confined to the range of 590 deg C to 750 deg C. (author)

 
 
 
 
181

Uptake and resource allocation of ammonium and nitrate in temperate seagrasses Posidonia and Amphibolis  

International Nuclear Information System (INIS)

Ecologically relevant estimates of seasonal variability in nitrogen uptake and allocation in two species of temperate seagrasses were obtained using in situ isotope-labelling approach. Significantly higher uptake rates of ammonium by leaves, roots and epiphytes of Amphibolis than Posidonia were observed. Overall, root uptake rates were lower than other components. Effect of season was not significant for leaves, roots or epiphytes of the two species. However, plankton uptake varied seasonally with higher rates in winter (0.98 mg N g-1 DW h-1). In contrast, nitrate uptake rates for various components were significantly affected by seasons. Uptake rates by plankton were highest ranging from 0.003 mg N g-1 DW h-1 (summer, Amphibolis) to 0.69 mg N g-1 DW h-1 (winter, Posidonia). Uptake of nitrate by roots was negligible. Biotic uptake rates for nitrate were an order of magnitude slower than ammonium, demonstrating an affinity for ammonium over nitrate as a preferred inorganic nitrogen source. Adelaide coastal waters have lost over 5000 ha of seagrasses, much of this attributed to nutrient inputs from wastewater, industrial and stormwater. Managing these inputs into future requires better understanding of the fate of nutrients, particularly biological uptake. This study attempts to quantify uptake rates of nitrogen by seagrasses.

182

Ductile-Brittle Transition Behavior in Tempered Martensitic SA508 Gr. 4N Ni-Mo-Cr Low Alloy Steels for Reactor Pressure Vessels  

International Nuclear Information System (INIS)

Reactor pressure vessels (RPVs) operate under severe conditions of elevated temperature, high pressure, and irradiation. Therefore, a combination of sufficient strength, toughness, good weldability, and high irradiation resistance are required for RPV materials. SA508 Gr.4N low alloy steel, which has higher Ni and Cr contents than those of commercial RPV steel, Gr.3 steel, is considered as a candidate material due to its excellent mechanical properties from tempered martensitic microstructure. The ferritic steels such as Gr.3 and Gr.4N low alloy steels reveal a ductile-brittle transition and large scatters in the fracture toughness within a small temperature range. Recently, there are some observations of the steeper transition behavior in the tempered martensitic steels, such as Eurofer97 than the transition behavior of commercial RPV steels. It was also reported that the fracture toughness increased discontinuously when the phase fraction of the tempered martensite was over a critical fraction in the heat affected zones of SA508 Gr.3. Therefore, it may be necessary to evaluate the changes of transition behavior with a microstructure for the tempered martensitic SA508 Gr.4N low alloy steel. In this study, the fracture toughness for SA508 Gr.4N low alloy steels was evaluated from a view point of the temperature dependency with phase fraction of tempered martensite controlled by cooling rate. Additionally, a possible modification of the fracture toughness master curve on of the fracture toughness master curve was proposed and discussed

183

Heading for Next Winter Haven  

Science.gov (United States)

Approaching its 47th month of a Mars surface mission originally planned to last three months, NASA's Spirit rover was also approaching the northern edge of a low plateau called 'Home Plate.' The rover's operators selected an area with north-facing slope there as a destination where Spirit would have its best chance of surviving low-solar-energy conditions of oncoming Martian winter. The yellow line on this map of the Home Plate area indicates Spirit's route from early February 2006, entering the mapped area from the north (top), to late November 2007, on the western edge of the bright-toned Home Plate plateau. The map covers an area about 160 meters (525 feet) across from west to east. Labels indicate the area intended for Spirit to spend many months spanning the rover's third Martian winter, the site where it spent about seven months (April to November 2006) spanning its second winter, and the site where it lost use of the drive motor for one of its six wheels. A north-facing slope helps Spirit maximizes electric output from its solar panels during winter months because Spirit is in the southern hemisphere of Mars, so the sun appears only in the northern sky during winter. For the third winter, which will reach its minimum solar-energy days in early June 2008, Spirit faces the challenge of having more dust on its solar panels than it had during its second winter. The base image for this map is a portion of a color image taken on Jan. 9, 2007, by the High Resolution Imaging Science Experiment camera on NASA's Mars Reconnaissance Orbiter.

2007-01-01

184

Enhanced Sampling in the Well-Tempered Ensemble  

CERN Document Server

We introduce the well-tempered ensemble (WTE) which is the biased ensemble sampled by well-tempered metadynamics when the energy is used as collective variable. WTE can be designed so as to have approximately the same average energy as the canonical ensemble but much larger fluctuations. These two properties lead to an extremely fast exploration of phase space. An even greater efficiency is obtained when WTE is combined with parallel tempering. Unbiased Boltzmann averages are computed on the fly by a recently developed reweighting method [M. Bonomi et al. J. Comput. Chem. 30, 1615 (2009)]. We apply WTE and its parallel tempering variant to the 2d Ising model and to a Go-model of HIV protease, demonstrating in these two representative cases that convergence is accelerated by orders of magnitude.

Bonomi, M

2009-01-01

185

Tempered-martensite embrittlement in a 12% Cr steel  

International Nuclear Information System (INIS)

The nature of tempered martensite embrittlement in a 12% Cr steel was investigated using notched bar impact testing and Auger Electron Spectroscopy (AES). A minimum in the room temperature impact energy and a maximum in the ductile-brittle transition temperature occurred on tempering at 5000C (2 hours) and were associated with a low temperature cleavage fracture mode. The temperature of maximum embrittlement coincided with the tempering treatment producing the Cr7C3/M2X ? M23C6 carbide transformation. Tempering at temperatures > 5000C produced a progressive reduction in hardness, a decrease in the ductile-brittle transition and a change in the fracture mechanism in the lower shelf energy regime to a total or partial intergranular mode. AES measurements on the intergranular facets revealed segregation of phosphorus and a concomitant chromium enrichment, which could be tentatively explained in terms of a phosphorus segregation process controlled by the grain boundary precipitation of M23C6. (author)

186

Significance of rate of work hardening in tempered martensite embrittlement  

International Nuclear Information System (INIS)

The main explanations for tempered martensite embrittlement are based on the effects of impurities and cementite precipitation on the prior austenite grain boundaries. There are some studies where the rate of work hardening is proposed as a potential reason for the brittleness. One steel was studied by means of a specially developed precision torsional testing device. The test steel had a high Si and Ni content so ? carbide and Fe3C appear in quite different tempering temperature ranges. The MS temperature is low enough so that self tempering does not occur. With the testing device it was possible to obtain the true stress - true strain curves to very high deformations. The minimum toughness was always associated with the minimum of rate of work hardening. The change of deformed steel volume before the loss of mechanical stability is proposed as at least one reason for tempered martensite embrittlement. The reasons for the minimum of the rate of work hardening are considered. (orig.)

187

Treatment of incarceration of the penis by tempered steel bushings.  

Science.gov (United States)

A case of penile incarceration secondary to a tempered steel ball bearing compromising the penile vascular supply is presented. The management of this case is described and guidelines for the management of similar cases reviewed. PMID:3584917

Klein, F A; Smith, M J

1987-01-01

188

Tempering and Annealing in a Verdier-Stockmayer Polymer  

Directory of Open Access Journals (Sweden)

Full Text Available Two Monte Carlo methods, simulated annealing and parallel tempering, were applied to a Verdier-Stockmayer polymer. The efficiency of the two algorithms in exploring the lowest energy state possible for the model polymers was measured by the number of energy-degenerate configurations (configurations that have the same energy but are structurally different. Parallel tempering consistently explored more energy-degenerate configurations as compared with simulated annealing.

E. R. Obias

2004-12-01

189

Computer simulation of quenched and tempered steel properties  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The algorithm of estimation of mechanical properties based on steel hardness has been established.Design/methodology/approach: Numerical modelling of hardness distribution in as-quenched steel specimen was performed by involving the results of simple experimental test, i.e., Jominy-test. Hardness of quenched and tempered steel has been expressed as function of maximal hardness of actual steel and hardness of actual steel with 50% of martensite in microstructure, according to the time and temperature of tempering. After that distribution of other relevant mechanical properties was predicted based on predicted as-quenched and tempered hardness of steel. Experimental investigation has been performed on low alloy steel. The established procedure for estimation of quenched and tempered properties of steel has been applied in computer simulation of mechanical properties of quenched and tempered steel workpiece of complex form.Findings: Algorithm of estimation of hardness of quenched and tempered steel was improved. It can be concluded that working stress of quenched and tempered shaft can be successfully predicted by proposed method. The proposed computer simulation method could be applied in failure prevention.Research limitations/implications: The research was focused only on carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of mechanical properties in heat treating practice. Estimation of as-quenched hardness distribution is based on time, relevant for structure transformation, i.e., time of cooling from 800 to 500°C (t8/5. The hardness in the quenched and tempered state is estimated from the as-quenched hardness. The prediction of yield strength and toughness of steel is based on steel hardness.Originality/value: Hardness distribution is predicted by involving the results of simple experimental test, i.e., Jominy-test in numerical modelling of steel quenching.

B. Smoljan

2011-06-01

190

Magnetic nondestructive technology for detection of tempered martensite embrittlement  

Science.gov (United States)

A nondestructive eddy current technique is used to evaluate tempered martensite embrittlement in 4340 AISI steels after quench and tempering in the range 240-550 °C. A relation between the responses of the magnetic induction (normalized impedance of the coil) and destructive Charpy impact test results has been established. The study shows that the eddy current method could be used to separate brittle parts due to the microstructure changes.

Kashefi, Mehrdad; Rafsanjani, Ali; Kahrobaee, Saeed; Alaee, Moeen

2012-11-01

191

Transformations of Carbides During Tempering of D3 Tool Steel  

Science.gov (United States)

The studies were performed on D3 tool steel hardened after austenitizing at 1050 °C during 30 min and tempering at 200-700 °C. Based on the diffraction studies performed from the extraction replicas, using electron microscopy, it was found that after 120-min tempering in the consecutive temperatures, the following types of carbides occur: Apart from higher mentioned carbides, there are also big primary carbides and fine secondary M7C3 carbides occurring, which did not dissolve during austenitizing.

Nykiel, Tadeusz; Hryniewicz, Tadeusz

2014-06-01

192

Effect of climate change on temperate forest ecosystems  

Digital Repository Infrastructure Vision for European Research (DRIVER)

In temperate climates groundwater can have a strong effect on vegetation, because it can influence the spatio-temporal distribution of soil moisture and therefore water and oxygen stress of vegetation. Current IPCC climate projections based on CO2 emission scenarios show a global temperature rise and change in precipitation regime, which will affect hydrological and vegetation systems. This thesis provides a quantitative framework for studying eco-hydrology in groundwater influenced temperate...

Brolsma, R. J.

2010-01-01

193

Contribution to the modelling of chocolate tempering process.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The tempering of chocolate, i.e. the process of crystallization of the desired morph; is a key step in its manufacturing by professional chocolatiers. In this work, a model of a tempering process based on seeding with solid chocolate grains is developed to enhance understanding and control of the system. The model aims to predict temperature field during melting and crystallization of the product. Therefore a mechanical stirrer is designed to simulate the manual mixing. Resulting flow field i...

Debaste, Fre?de?ric; Kegelaers, Yves; Ben Amor, Hatem; Halloin, Ve?ronique

2007-01-01

194

Method for heating, forming and tempering a glass sheet  

Science.gov (United States)

A method for heating, forming and tempering a glass sheet including the steps of heating at least one glass sheet to at least a first predetermined temperature, applying microwave energy to the glass sheet to heat the glass sheet to at least a second predetermined temperature, forming the glass sheet to a predetermined configuration, and cooling an outer surface of the glass sheet to at least a third predetermined temperature to temper the glass sheet.

Boaz, Premakaran Tucker (Livonia, MI); Sitzman, Gary W. (Walled Lake, MI)

1998-01-01

195

A comparison of air particulate matter and associated polycyclic aromatic hydrocarbons in some tropical and temperate urban environments  

Science.gov (United States)

A 12 month study of urban concentrations of total suspended particulates (TSP) and 20 polycyclic aromatic hydrocarbons (PAH) was carried out in Seoul (South Korea), Hong Kong, Bangkok (Thailand), Jakarta (Indonesia) and Melbourne (Australia). Concentrations of particulate matter in the atmosphere varied widely between the cities over the course of the study, ranging from a low of 24.1 ?g m -3 in Melbourne during the winter to a high of 376.2 ?g m -3 in Jakarta during the dry season. Seasonal variations in both TSP and PAH were observed in the tropical cities in the study with higher concentrations during the dry season and lower concentrations during the wet season. TSP and PAH concentrations are correlated with each other in these cities, suggesting that they have related sources and sinks for these cities. In the temperate cities of Melbourne and Seoul, PAH concentrations were higher during the cold winter season and lower during the warm summer. However, TSP was quite variable over the years in these latter cities and no clear seasonal trend was observed. A number of factors have been investigated which could be contributing to seasonal variations in pollutant levels. In the temperate climates, increased emissions due to the use of fossil fuels for heating in the winter is evident. However, an interrogation of the database with respect to the other factors such as (1) increased photolytic degradation during the summer, (2) transport of pollutants from other sources, (3) removal of PAH via wet deposition and in-cloud scavenging mechanisms and (4) volatilisation of lower molecular weight species during periods of high temperature indicates the importance of multiple processes. Even though there are clearly much lower levels of both particulates and PAH in the wet season of the tropical climates, no statistically significant correlations have been observed between rainfall levels and pollutant concentrations.

Panther, B. C.; Hooper, M. A.; Tapper, N. J.

196

TEMPER: an acronym for ankle sprain rehabilitation.  

Science.gov (United States)

As has been previously discussed, the incidence and resultant associated disabilities of ankle sprains have been well documented in the literature. The staggering statistics on long-term disability show that there is no such thing as a simple ankle sprain. The degree of disability is related to the extent of the initial injury as well as the follow-up medical care provided. It is this fact that requires a complete understanding of the injury as well as a proper treatment and rehabilitation program. One of the reasons cited for the long-term disability or lack of consistently good results in treating ankle sprains is the lack of uniformity in treatment. One possible reason is the lack of agreement in diagnostic techniques as well as the end diagnosis of a particular grade of ankle sprain. If a sprain is managed correctly, resultant disability will be kept to a minimum. A proper rehabilitation program may be the most important factor in preventing chronic instability. The acronym RICE falls short of complete ankle management. RICE primarily addresses the ankle edema. Thus, the patient's ankle is only partially rehabilitated. A rational approach to the management of ankle sprains is given. Upon reviewing a complete protocol for ankle sprain rehabilitation, the acronym TEMPER can be used judiciously to remember the key steps in the treatment plan. Through the use of this acronym, one can institute a complete rehabilitation program. PMID:3293757

Rzonca, E C; Lue, B Y

1988-07-01

197

Retained austenite and tempered martensite embrittlement in medium carbon steels  

International Nuclear Information System (INIS)

Electron microscopy, diffraction and microanalysis, X-ray diffraction, and auger spectroscopy have been used to study quenched and quenched and tempered 0.3 pct carbon low alloy steels. Some in sit fracture studies were also carried out in a high voltage electron microscope. Tempered martensite embrittlement (TME) is shown to arise primarily as a microstructural constraint associated with decomposition of interlath retained austenite into M3C films upon tempering in the range of 2500C to 4000C. In addition, intralath Widmanstatten Fe3C forms from epsilon carbide. The fracture is transgranular with respect to prior austenite. The situation is analogous to that in upper bainite This TME failure is different from temper embrittlement (TE) which occurs at higher tempering temperatures (approximately 5000C), and is not a microstructural effect but rather due to impurity segregation (principally sulfur in the present work) to prior austenite grain boundaries leading t intergranular fracture along those boundaries. Both failures can occur in the same steels, depending on the tempering conditions

198

Dung beetle communities: a neotropical-north temperate comparison  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Dung beetle communities have been compared across north temperate latitudes. Tropical dung beetle communities appear to be more diverse based on studies using different methodologies. Here, we present results from a standardized sampling protocol used to compare dung beetle communities across five n [...] eotropical forests in Brazil and Ecuador and two warm, north temperate forests in Mississippi and Louisiana. Species richness in the tropical forests was three to seven times higher than the temperate forests, as would be expected by studies of other taxa across tropical and temperate latitudes. Average body size in the temperate forests was larger than the tropical forests, as predicted by Bergmann's rule. Dung beetle abundance and volume per trap-day were generally higher in Ecuador than Brazil, and higher in Mississippi than Louisiana, but there were no tropical-temperate differences. Species rank-abundance curves were similar within countries and between countries. Rank-volume distributions indicated a smaller range of beetle body sizes in Ecuador versus Brazil or the USA. Community similarity was high within countries and low between countries. Community differences between Brazil and Ecuador sites may be explained by differences in productivity based on geological age of the soils.

Meghan G, Radtke; Cláudio R V da, Fonseca; G Bruce, Williamson.

2010-02-01

199

Influence of tempering temperature on mechanical properties of cast steels  

Directory of Open Access Journals (Sweden)

Full Text Available The paper presents results of research on the influence of tempering temperature on structure and mechanical properties of bainite hardened cast steel: G21CrMoV4 – 6 (L21HMF and G17CrMoV5 – 10 (L17HMF. Investigated cast steels were taken out from internal frames of steam turbines serviced for long time at elevated temperatures. Tempering of the investigated cast steel was carried out within the temperature range of 690 ÷ 730 C (G21CrMoV4 – 6 and 700 ÷ 740 C (G17CrMoV5 – 10. After tempering the cast steels were characterized by a structure of tempered lower bainite with numerous precipitations of carbides. Performed research of mechanical properties has shown that high temperatures of tempering of bainitic structure do not cause decrease of mechanical properties beneath the required minimum.oo It has also been proved that high-temperature tempering (>720 oC ensures high impact energy at the 20% decrease of mechanical properties.

G. Gola?ski

2008-12-01

200

Dung beetle communities: a neotropical-north temperate comparison  

Scientific Electronic Library Online (English)

Full Text Available SciELO Brazil | Language: English Abstract in english Dung beetle communities have been compared across north temperate latitudes. Tropical dung beetle communities appear to be more diverse based on studies using different methodologies. Here, we present results from a standardized sampling protocol used to compare dung beetle communities across five n [...] eotropical forests in Brazil and Ecuador and two warm, north temperate forests in Mississippi and Louisiana. Species richness in the tropical forests was three to seven times higher than the temperate forests, as would be expected by studies of other taxa across tropical and temperate latitudes. Average body size in the temperate forests was larger than the tropical forests, as predicted by Bergmann's rule. Dung beetle abundance and volume per trap-day were generally higher in Ecuador than Brazil, and higher in Mississippi than Louisiana, but there were no tropical-temperate differences. Species rank-abundance curves were similar within countries and between countries. Rank-volume distributions indicated a smaller range of beetle body sizes in Ecuador versus Brazil or the USA. Community similarity was high within countries and low between countries. Community differences between Brazil and Ecuador sites may be explained by differences in productivity based on geological age of the soils.

Meghan G, Radtke; Cláudio R V da, Fonseca; G Bruce, Williamson.

 
 
 
 
201

Strong seasonal effect of moderate experimental warming on plankton respiration in a temperate estuarine plankton community  

Science.gov (United States)

Climate change projections forecast a 1.1-6.4 °C global increase in surface water temperature and a 3 °C increase for the Baltic Sea. This study examined the short-term interactive effects of a realistic future temperature increase (3 °C) on pelagic respiration and bacterioplankton growth and phytoplankton photosynthesis in situ. This study was undertaken throughout a full seasonal cycle in the northern Baltic Sea. We found marked positive short-term effects of temperature on plankton respiration but no significant effect on bacterioplankton growth or phytoplankton photosynthesis. Absolute respiration rates remained similar to other comparable environments at the in situ temperature. With the 3 °C temperature increase, respiration rates in situ increased up to 5-fold during the winter and 2-fold during the summer. A maximum seasonal Q10 value of 332 was observed for respiration during the cold winter months (twater ? 0 °C), and summer Q10 values were comparatively high (9.1). Q10 values exhibited a significant inverse relationship to water temperature during winter. Our results thereby suggest that plankton respiration in this coastal zone is more temperature sensitive than previously reported. In addition, field data indicated that plankton respiration switched from being temperature limited to being limited by dissolved organic carbon (DOC) after the simulated temperature increase. Assuming that our observations are relevant over longer time scales, climate change may worsen hypoxia, increase CO2 emissions and create a more heterotrophic food web in coastal zones with a high load of riverine DOC.

Panigrahi, Satya; Nydahl, Anna; Anton, Peter; Wikner, Johan

2013-12-01

202

Thermal dependence of locomotor performance in two cool-temperate lizards.  

Science.gov (United States)

Temperate-zone ectotherms experience varying or very low ambient temperatures and may have difficulty in attaining preferred body temperatures. Thus, adaptations to reduce the thermal dependence of physiological processes may be present. We measured the optimal temperature range for sprint speed and compared it with the selected body temperatures (T (sel)) of two sympatric, cool-temperate lizards: the diurnal skink Oligosoma maccanni and the primarily nocturnal gecko Woodworthia (previously Hoplodactylus) "Otago/Southland". We also investigated whether time-of-day influenced sprint speed. Contrary to results for other reptiles, we found that time-of-day did not influence speed in either species. For each species, the optimal temperature range for sprinting and T (sel) overlapped, supporting the 'thermal coadaptation' hypothesis. However, the optimal range of temperatures for speed is not always attainable during activity by either species, which have limited opportunities to attain T (sel) in the field. The thermal sensitivity of sprint speed in these two species does not appear to have evolved to fully match their current thermal environment. More data on cold-adapted species are needed to fully understand physiological adaptation in ectotherms. PMID:21547573

Gaby, Mya J; Besson, Anne A; Bezzina, Chalene N; Caldwell, Amanda J; Cosgrove, Sarai; Cree, Alison; Haresnape, Steff; Hare, Kelly M

2011-09-01

203

Coastal zone  

International Nuclear Information System (INIS)

The report entitled Climate Change Impacts and Adaptation : A Canadian Perspective, presents a summary of research regarding the impacts of climate change on key sectors over the past five years as it relates to Canada. This chapter on the coastal zone focuses on the impact of climate change on Canada's marine and Great Lakes coasts with tips on how to deal with the impacts associated with climate change in sensitive environments. This report is aimed at the sectors that will be most affected by adaptation decisions in the coastal zone, including fisheries, tourism, transportation and water resources. The impact of climate change in the coastal zone may include changes in water levels, wave patterns, storm surges, and thickness of seasonal ice cover. The Intergovernmental Panel on Climate Change projects global average sea level will rise between 9 and 88 centimetres between 1990 to 2100, but not all areas of Canada will experience the same rate of future sea level change. The main physical impact would be shoreline change that could result in a range of biophysical and socio-economic impacts, some beneficial, some negative. The report focuses on issues related to infrastructure and communities in coastal regions. It is noted that appropriate human adaptation will play a vital role in reducing the extent of potential impacts by decreasing the vulnerability of average zone to climate change. The 3 main trends in coastal adaptation include: (1) increase in soft protection, retreat and accommodation, (2) reliance on technology such as geographic information systems to manage information, and (3) awareness of the need for coastal adaptation that is appropriate for local conditions. 61 refs., 7 figs

204

Effects of temper level on the dependence of fatigue crack growth threshold and crack closure on the prior austenitic grain size  

Science.gov (United States)

An attempt has been made to systematically investigate the effects of microstructural parameters, such as the prior austenite grain size (PAGS), in influencing the resistance to fatigue crack growth (FCG) in the near-threshold region under three different temper levels in a quenched and tempered high-strength steel. By austenitizing at various temperatures, the PAGS was varied from about 0.7 to 96 ?m. The microstructures with these grain sizes were tempered at 200 °C, 400 °C, and 530 °C and tested for fatigue thresholds and crack closure. It has been found that, in general, three different trends in the dependence of both the total threshold stress intensity range, ? K th , and the intrinsic threshold stress intensity range, ? K eff, th , on the PAGS are observable. By considering in detail the factors such as cyclic stress-strain behavior, environmental effects on FCG, and embrittlement during tempering, the present observations could be rationalized. The strong dependence of ? K th and ? K eff, th on PAGS in microstructures tempered at 530 °C has been primarily attributed to cyclic softening and thereby the strong interaction of the crack tip deformation field with the grain boundary. On the other hand, a less strong dependence of ? K th and ? K eff, th on PAGS is suggested to be caused by the cyclic hardening behavior of lightly tempered microstructures occurring in 200 °C temper. In both microstructures, crack closure influenced near-threshold FCG (NTFCG) to a significant extent, and its magnitude was large at large grain sizes. Microstructures tempered at the intermediate temperatures failed to show a systematic variation of ?Kth and ?Keff, th with PAGS. The mechanisms of intergranular fracture vary between grain sizes in this temper. A transition from “microstructure-sensitive” to “microstructure-insensitive” crack growth has been found to occur when the zone of cyclic deformation at the crack tip becomes more or less equal to PAGS. Detailed observations on fracture morphology and crack paths corroborate the grain size effects on fatigue thresholds and crack closure.

Ravichandran, K. S.; Dwarakadasa, E. S.

1990-12-01

205

Development of passive design zones in China using bioclimatic approach  

International Nuclear Information System (INIS)

This paper presents the work on development of passive design zones for different climates in China. A total of 18 cities representing the five major climatic types, namely severe cold, cold, hot summer and cold winter, mild and hot summer and warm winter were selected for climatic analysis. Measured weather data were gathered and analysed. A bioclimatic approach was adopted in which the comfort zone and 12 monthly climatic lines were determined and plotted on the psychrometric chart for each city. From these bioclimatic charts, the potential use of passive design strategies such as solar heating, natural ventilation, thermal mass with/without night ventilation and evaporative cooling was assessed. A total of nine passive design strategy zones were identified, and appropriate design strategies suggested for both summer and winter consideration

206

Development of passive design zones in China using bioclimatic approach  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the work on development of passive design zones for different climates in China. A total of 18 cities representing the five major climatic types, namely severe cold, cold, hot summer and cold winter, mild and hot summer and warm winter were selected for climatic analysis. Measured weather data were gathered and analysed. A bioclimatic approach was adopted in which the comfort zone and 12 monthly climatic lines were determined and plotted on the psychrometric chart for each city. From these bioclimatic charts, the potential use of passive design strategies such as solar heating, natural ventilation, thermal mass with/without night ventilation and evaporative cooling was assessed. A total of nine passive design strategy zones were identified, and appropriate design strategies suggested for both summer and winter consideration. (author)

Lam, Joseph C. [Building Energy Research Group, Department of Building and Construction, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong (China); Yang, Liu; Liu, Jiaping [School of Architecture, Xi' an University of Architecture and Technology, Shaanxi (China)

2006-04-15

207

Variation in leaf flushing date influences autumnal senescence and next year's flushing date in two temperate tree species.  

Science.gov (United States)

Recent temperature increases have elicited strong phenological shifts in temperate tree species, with subsequent effects on photosynthesis. Here, we assess the impact of advanced leaf flushing in a winter warming experiment on the current year's senescence and next year's leaf flushing dates in two common tree species: Quercus robur L. and Fagus sylvatica L. Results suggest that earlier leaf flushing translated into earlier senescence, thereby partially offsetting the lengthening of the growing season. Moreover, saplings that were warmed in winter-spring 2009-2010 still exhibited earlier leaf flushing in 2011, even though the saplings had been exposed to similar ambient conditions for almost 1 y. Interestingly, for both species similar trends were found in mature trees using a long-term series of phenological records gathered from various locations in Europe. We hypothesize that this long-term legacy effect is related to an advancement of the endormancy phase (chilling phase) in response to the earlier autumnal senescence. Given the importance of phenology in plant and ecosystem functioning, and the prediction of more frequent extremely warm winters, our observations and postulated underlying mechanisms should be tested in other species. PMID:24799708

Fu, Yongshuo S H; Campioli, Matteo; Vitasse, Yann; De Boeck, Hans J; Van den Berge, Joke; AbdElgawad, Hamada; Asard, Han; Piao, Shilong; Deckmyn, Gaby; Janssens, Ivan A

2014-05-20

208

Variation in leaf flushing date influences autumnal senescence and next year's flushing date in two temperate tree species  

Science.gov (United States)

Recent temperature increases have elicited strong phenological shifts in temperate tree species, with subsequent effects on photosynthesis. Here, we assess the impact of advanced leaf flushing in a winter warming experiment on the current year’s senescence and next year’s leaf flushing dates in two common tree species: Quercus robur L. and Fagus sylvatica L. Results suggest that earlier leaf flushing translated into earlier senescence, thereby partially offsetting the lengthening of the growing season. Moreover, saplings that were warmed in winter–spring 2009–2010 still exhibited earlier leaf flushing in 2011, even though the saplings had been exposed to similar ambient conditions for almost 1 y. Interestingly, for both species similar trends were found in mature trees using a long-term series of phenological records gathered from various locations in Europe. We hypothesize that this long-term legacy effect is related to an advancement of the endormancy phase (chilling phase) in response to the earlier autumnal senescence. Given the importance of phenology in plant and ecosystem functioning, and the prediction of more frequent extremely warm winters, our observations and postulated underlying mechanisms should be tested in other species. PMID:24799708

Fu, Yongshuo S. H.; Campioli, Matteo; Vitasse, Yann; De Boeck, Hans J.; Van den Berge, Joke; AbdElgawad, Hamada; Asard, Han; Piao, Shilong; Deckmyn, Gaby; Janssens, Ivan A.

2014-01-01

209

Peculiarities of Over-Wintering of Linear and Hybrid Winter Rape in Warming-Up Autumn-Winter period  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The experiment carried out in the Experimental Station of Lithuanian University of Agriculture in 2009 – 2010. The soil is shallow calcareous Luvisols (Calc(ar)i-Epihypogleyic Luvisol). The aim of our investigation was to determine the effect of sowing time of winter oilseed rape on autumn rosette chemical composition and over-wintering. Chemical composition of rossete of winter rape sown at different time influenced crop over-wintering – significant correlation between this indicators wa...

Dunauskaite?, Rimante?

2011-01-01

210

Photoperiod and temperature responses of bud swelling and bud burst in four temperate forest tree species.  

Science.gov (United States)

Spring phenology of temperate forest trees is optimized to maximize the length of the growing season while minimizing the risk of freezing damage. The release from winter dormancy is environmentally mediated by species-specific responses to temperature and photoperiod. We investigated the response of early spring phenology to temperature and photoperiod at different stages of dormancy release in cuttings from four temperate tree species in controlled environments. By tracking bud development, we were able to identify the onset of bud swelling and bud growth in Acer pseudoplatanus L., Fagus sylvatica L., Quercus petraea (Mattuschka) Liebl. and Picea abies (L.) H. Karst. At a given early stage of dormancy release, the onset and duration of the bud swelling prior to bud burst are driven by concurrent temperature and photoperiod, while the maximum growth rate is temperature dependent only, except for Fagus, where long photoperiods also increased bud growth rates. Similarly, the later bud burst was controlled by temperature and photoperiod (in the photoperiod sensitive species Fagus, Quercus and Picea). We conclude that photoperiod is involved in the release of dormancy during the ecodormancy phase and may influence bud burst in trees that have experienced sufficient chilling. This study explored and documented the early bud swelling period that precedes and defines later phenological stages such as canopy greening in conventional phenological works. It is the early bud growth resumption that needs to be understood in order to arrive at a causal interpretation and modelling of tree phenology at a large scale. Classic spring phenology events mark visible endpoints of a cascade of processes as evidenced here. PMID:24713858

Basler, David; Körner, Christian

2014-04-01

211

Structure and properties of the tool steel after electron beam treatment and following tempering  

International Nuclear Information System (INIS)

The possibility of changing the surface structure of chromium tool steel has been considered. The given properties were reached through the surface remelting by electron beam with following tempering of strengthened layer. The found distinguished zones with different structure and properties are formed as the result of this treatment. It is shown that for hipereutectoid steel the thermal furnace annealing at 300 deg C is necessary for strengthened surface layer forming after electron beam remelting. The same result can be had by means of short-term heating with electronic beam up to higher temperatures, but is not higher A1. The evaluation of temperature fields was carried out by numerical solution of nonstationary heat conductivity equation

212

Low-frequency radar sounding of temperate ice masses in Southern Alaska  

Science.gov (United States)

We present the Warm Ice Sounding Explorer (WISE), a low-frequency (2.5 MHz) radar for the sounding of temperate ice. WISE deployment in southern Alaska in 2008 and 2012 provides comprehensive measurements of glacier thickness, reveals deep valleys beneath glaciers and the full extent of zones grounded below sea level. The east branch of Columbia Glacier is deeper that its main branch and remains below sea level 20 km farther inland. Ice is 1000 m deep on Tazlina Glacier. On Bering glacier, two sills separate three deep bed depressions (>1200 m) that coincide with the dynamic balance lines during surges. The piedmont lobe of Malaspina Glacier and the lower reaches of Hubbard Glacier are entirely grounded below sea level 40 and 10 km, respectively, from their termini. Knowledge of ice thickness in these regions helps better understand their glacier dynamics, mass balance, and impact on sea level.

Rignot, E.; Mouginot, J.; Larsen, C. F.; Gim, Y.; Kirchner, D.

2013-10-01

213

Fatigue crack initiation and propagation in a quenched and tempered niobium bearing HSLA steel  

Science.gov (United States)

The fatigue crack initiation and propagation behavior of a niobium bearing HSLA steel heat treated to give two tempered martensitic microstructures presumably with and without fine niobium carbides has been studied by light microscopy, electron microscopy, and strain gage measurements of plastic zone deformation. The high cycle, stress controlled fatigue life of the steel in both heat treated conditions was quite similar with the steel presumably containing the fine niobium carbides having slightly better resistance at low stress amplitudes. This slightly better high cycle resistance is associated with better resistance to fatigue crack initiation for this heat treatment. The fatigue crack propagation behavior of the steel was the opposite. The steel presumably containing the fine niobium carbides exhibited a much faster fatigue crack growth rate than that without them. The difference in growth rates is explained in terms of the plastic work expended during the propagation of the fatigue crack.

Kwun, S. I.; Fournelle, R. A.

1982-03-01

214

Why Do Some Evergreen Species Keep Their Leaves for a Second Winter, While Others Lose Them?  

Directory of Open Access Journals (Sweden)

Full Text Available In subtropical montane semi-moist forest in SW China (SMSF, a large majority of evergreen tree and tall shrub species was found to have only one cohort of old leaves in early spring. In contrast, almost all species of evergreen tree and tall shrub in warm temperate rain forest (WTRF in Japan and sclerophylls in Mediterranean-climate forest (MSF of the Mediterranean Basin have two or more cohorts of old leaves in early spring; they drop their oldest cohort during or soon after leaf outgrowth in spring. Japanese WTRF has no dry season and MSF a dry summer. SMSF has a dry winter. On four evergreen Rhododendron species from SW China with only one cohort of old leaves in spring when in cultivation in Scotland, the majority of leaves in the senescing cohort fell by the end of December. We hypothesize that with dry winters, there is an advantage to dropping older leaves in autumn, because there is a low chance of appreciable positive assimilation in winter and a high chance of desiccation, reducing the resorption of dry mass and mineral nutrients from ageing leaves. Our hypothesis may be extended to cover evergreens at high altitude or high latitude that experience cold soils in winter.

Peter J. Grubb

2014-10-01

215

36 CFR 1002.19 - Winter activities.  

Science.gov (United States)

...AND RECREATION § 1002.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding, innertubing, tobogganing and similar winter sports are prohibited on Presidio Trust roads and in parking areas open to motor vehicle traffic,...

2010-07-01

216

36 CFR 2.19 - Winter activities.  

Science.gov (United States)

...USE AND RECREATION § 2.19 Winter activities. (a) Skiing, snowshoeing, ice skating, sledding, innertubing, tobogganing and similar winter sports are prohibited on park roads and in parking areas open to motor vehicle traffic, except as...

2010-07-01

217

Essential Outdoor Sun Safety Tips for Winter  

Science.gov (United States)

Essential Outdoor Sun Safety Tips for Winter Winter sports enthusiasts are at increased risk for overexposure to the sun's ultraviolet (UV) ... skiing! Be Mindful of Time Spent in the Sun, Regardless of the Season If possible, ski early ...

218

Evolution of microsatellite Loci of tropical and temperate anguilla eels.  

Science.gov (United States)

Anguilla eels are divided into temperate and tropical eels, based on their major distributions. The present study collected two temperate eels, Anguilla japonica and Anguilla anguilla, and two tropical eels, Anguilla marmorata and Anguilla bicolor pacifica, to examine two questions: do temperate and tropical Anguilla eels have different genetic polymorphic patterns?; and do temperate Anguilla japonica and Anguilla anguilla have a closer relationship to each other than to tropical eels? In total, 274 sequences were cloned and sequenced from six conserved microsatellite loci to examine polymorphic patterns of these four catadromous eels. Different mutational events, including substitutions, and repeat-unit deletions and insertions, appeared in major regions, while different point mutations were observed in flanking regions. The results implied that parallel patterns of microsatellite sequences occurred within both tropical and temperate freshwater eels. Consensus flanking sequences of six homologous loci from each of the four species were constructed. Genetic distances ranged from 0.044 (Anguilla bicolor pacifica vs. Anguilla marmorata) to 0.061 (Anguilla marmorata vs. Anguilla anguilla). The tree topology suggests the hypothesis of Anguilla japonica and Anguilla anguilla being a sister group must be rejected. PMID:22605978

Tseng, Mei-Chen

2012-01-01

219

Evolution of Microsatellite Loci of Tropical and Temperate Anguilla Eels  

Directory of Open Access Journals (Sweden)

Full Text Available Anguilla eels are divided into temperate and tropical eels, based on their major distributions. The present study collected two temperate eels, Anguilla japonica and Anguilla anguilla, and two tropical eels, Anguilla marmorata and Anguilla bicolor pacifica, to examine two questions: do temperate and tropical Anguilla eels have different genetic polymorphic patterns?; and do temperate Anguilla japonica and Anguilla anguilla have a closer relationship to each other than to tropical eels? In total, 274 sequences were cloned and sequenced from six conserved microsatellite loci to examine polymorphic patterns of these four catadromous eels. Different mutational events, including substitutions, and repeat-unit deletions and insertions, appeared in major regions, while different point mutations were observed in flanking regions. The results implied that parallel patterns of microsatellite sequences occurred within both tropical and temperate freshwater eels. Consensus flanking sequences of six homologous loci from each of the four species were constructed. Genetic distances ranged from 0.044 (Anguilla bicolor pacifica vs. Anguilla marmorata to 0.061 (Anguilla marmorata vs. Anguilla anguilla. The tree topology suggests the hypothesis of Anguilla japonica and Anguilla anguilla being a sister group must be rejected.

Mei-Chen Tseng

2012-04-01

220

Effects of tempering on internal friction of carbon steels  

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} Time tempering dependent microstructure of two steels is studied by internal friction. {yields} Internal friction indicates the interactions of dislocations with carbon and carbides. {yields} Internal friction detects the first stage of tempering. {yields} Precipitation hardening is detected by the decrease in the background. - Abstract: Two steels containing 0.626 and 0.71 wt.% carbon have been studied to determine the effects of tempering on the microstructure and the internal friction. The steels were annealed at 1093 K, quenched into water and tempered for 60 min at 423 K, 573 K and 723 K. The increase of the tempering time diminishes the martensite tetragonality due to the redistribution of carbon atoms from octahedrical interstitial sites to dislocations. Internal friction spectrum is decomposed into five peaks and an exponential background, which are attributed to the carbide precipitation and the dislocation relaxation process. Simultaneous presence of peaks P1 and P2 indicates the interaction of dislocations with the segregated carbon and carbide precipitate.

Hoyos, J.J., E-mail: jjhoyos@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Ghilarducci, A.A., E-mail: friccion@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Salva, H.R., E-mail: salva@cab.cnea.gov.ar [Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Instituto Balseiro-Universidad Nacional de Cuyo, Consejo Nacional de Investigaciones Cientificas y Tecnologicas, Av. Bustillo 9500, 8400 Bariloche RN (Argentina); Chaves, C.A., E-mail: cachaves@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia); Velez, J.M., E-mail: jmvelez@unal.edu.co [Grupo de Ciencia y Tecnologia de los Materiales, Universidad Nacional de Colombia, Sede Medellin, Carrera 80 Numero 65-223, Medellin (Colombia)

2011-04-15

 
 
 
 
221

TEM studies of tempered structural steels with Ni  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: The reason for writing this paper was to describe the influence of Ni addition on the microstructure of structural steels after tempering. In this investigation, four model alloys of the variable concentration of Ni and constant concentration of carbon and other elements were used.Design/methodology/approach: The alloys were melted in air and hot forged into bars 20×35 mm. The samples for investigations were machined after normalizing. All samples for TEM investigations were used in quenched and tempered conditions. Quenching was performed in oil at room temperature. After quenching samples were tempered at 200°C for 2 h. The microstructure of the investigated steels were investigated using JEM200CX transmission electron microscope.Findings: An increase of Ni content in investigated structural steels causes a decrease of ? carbide concentration in their microstructure after tempering at 200°C for 2 hours. Cementite precipitates in these steels independently on the boundaries of martensite needles boundaries and on the twin boundaries in the areas in which the precipitates of ? carbide dissolved. Research limitations/implications: Presented results may be used to design new technologies of tempering of structural steels with nickel addition.Originality/value: Morphology of ? carbides precipitates.

J. Pacyna

2007-03-01

222

A note on the water budget of temperate glaciers  

Directory of Open Access Journals (Sweden)

Full Text Available In this note, the total dissipative melting in temperate glaciers is studied. The analysis is based on the notion that the dissipation is determined by the loss of potential energy due to the downward motion of mass (ice, snow, meltwater and rain. A mathematical formulation of the dissipation is developed and applied to a simple glacier geometry. In the next step, meltwater production resulting from enhanced ice motion during a glacier surge is calculated. The amount of melt energy available follows directly from the lowering of the centre of gravity of the glacier. To illustrate the concept, schematic calculations are presented for a number of glaciers with different geometric characteristics. Typical dissipative melt rates, expressed as water-layer depth averaged over the glacier, range from a few centimetres per year for smaller glaciers to half a metre per year for Franz Josef Glacier, one of the most active glaciers in the world (in terms of mass turnover. The total generation of meltwater during a surge is typically half a metre. For Variegated Glacier a value of 70 cm is found, for Kongsvegen 20 cm. These values refer to water layer depth averaged over the entire glacier. The melt extit{rate} depends on the duration of the surge. It is generally an order of magnitude greater than water production by `normal' dissipation. On the other hand, the additional basal melt rate during a surge is comparable in magnitude with the water input from meltwater and precipitation. This suggests that enhanced melting during a surge does not grossly change the total water budget of a glacier. Basal water generated by enhanced sliding is an important ingredient in many theories of glacier surges. It provides a positive feedback mechanism that actually makes the surge happen. The results found here suggest that this can only work if water generated by enhanced sliding accumulates in a part of the glacier base where surface meltwater and rain have no or very limited access. This finding seems compatible with the fact that, on many glaciers, surges are initiated in the lower accumulation zone.

J. Oerlemans

2013-09-01

223

A note on the water budget of temperate glaciers  

Directory of Open Access Journals (Sweden)

Full Text Available In this note the total dissipative melting in temperate glaciers is studied. The analysis is based on the notion that the dissipation is determined by the loss of potential energy, due to the downward motion of mass (ice, snow, meltwater and rain. A mathematical formulation of the dissipation is developed and applied to a simple glacier geometry. In a next step, meltwater production resulting from enhanced ice motion during a glacier surge is calculated. The amount of melt energy available follows directly from the lowering of the centre of gravity of the glacier. To illustrate the concept, schematic calculations are presented for a number of glaciers with different geometric characteristics. Typical dissipative melt rates, expressed as water-layer depth averaged over the glacier, range from a few cm per year for smaller glaciers to half a meter per year for Franz-Josef Glacier, one of the most active glaciers in the world (in terms of mass turnover. The total generation of meltwater during a surge is typically half a meter. For Variegated Glacier a value of 70 cm is found, for Kongsvegen 20 cm. These values refer to water layer depth averaged over the entire glacier. The melt rate depends on the duration of the surge. It is generally an order of magnitude larger than the water production by "normal" dissipation. On the other hand, the additional basal melt rate during a surge is comparable in magnitude to the water input from meltwater and precipitation. This suggests that enhanced melting during a surge does not grossly change the total water budget of a glacier. Basal water generated by enhanced sliding is an important ingredient of many theories of glacier surges. It provides a positive feedback mechanism that actually makes the surge happen. The results found here suggest that this can only work if water generated by enhanced sliding is accumulating in a part of the glacier base where surface meltwater and rain has no or very limited access. This finding seems compatible with the fact that on many glaciers surges are initiated in the lower accumulation zone.

J. Oerlemans

2013-06-01

224

Britannica Sporting Record: The Winter Games  

Science.gov (United States)

Encyclopaedia Britannica's Olympic Winter Games site offers detailed Olympic information and history. Offerings include an overview of the Olympic movement, histories of each of the past seventeen Olympic Winter Games, articles about the events included in the Winter Games, biographies of past competitors, and a searchable Olympic Record database. This well-researched site provides an interesting backdrop for this year's Winter Games in Nagano, Japan.

Encyclopaedia Britannica, Inc.

1998-01-01

225

Water-vapor content in the atmosphere of arid zone  

Science.gov (United States)

The variation in water-vapor content W in the atmosphere of the arid zone is studied. The seasonal oscillations in W for the arid zone are characterized by changes in the moisture content from 2.3 to 3.6 times during the transition from winter to summer. The summer-fall period is characterized by a well-expressed midday minimum of moisture content. In winter the moisture content monotonically decreases during the day. In spring the water-vapor content has a wide maximum in midday. The water-vapor content in the atmosphere during dust haze increases up to two times.

Abdullaev, S. F.; Maslov, V. A.; Nazarov, B. I.; Salikhov, T. Kh.

2014-03-01

226

WINTER WHEAT CULTIVATION METHODS INFLUENCE ON VOLGOGRAD REGION CHESTNUT SOILS FERTILITY ??????? ??????? ???????????? ?????? ??????? ?? ?????????? ?????????? ???? ????????????? ???????  

Directory of Open Access Journals (Sweden)

Full Text Available The authors of the work offer to apply the new productive kinds of winter wheat: Rosinka Tarasovskaya and Donskoy surprise, and also the use of growth regulators Albit and Novosil, influencing on chestnut soils fertility and wheat crop productivity in dry steppe zone in Volgograd region

Kalmykova E. V.

2012-01-01

227

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.  

Science.gov (United States)

...Winter Harbor Lobster Boat Race, Winter Harbor, ME...Winter Harbor Lobster Boat Race, Winter Harbor, ME...modify, or cancel the race as conditions or circumstances...of this regulation and other applicable laws. ...this section will be in effect the second Sunday...

2010-07-01

228

Resistance to small plastic strains during martensite tempering under tension  

Energy Technology Data Exchange (ETDEWEB)

The mechanism of plastic deformation of martensite of a series of hardened steels (N18, 20KhG, 50KhFA and others) during tempering under tension and the role of residual internal microstresses and phase transformations are studied. It is shown that martensite low resistance to small plastic deformations during tempering under tension which is usually associated with phase transformations depends as well on the level of residual internal microstresses in the martensite structure. The decrease of resistance to deformation in the course of the decomposition of a solid solution is due to weakening of martensitic matrix because of carbon departure from the solid solution and carbide coarsening. An assumption is made that martensite plastic deformation during tempering under tension is realized at the expense of the directed microplastic deformation in the regions of higher concentration of internal stresses.

Zabil' skij, V.V.; Sarrak, V.I. (AN SSSR, Sverdlovsk. Inst. Fiziki Metallov)

1982-11-01

229

Resistance to small plastic strains during martensite tempering under tension  

International Nuclear Information System (INIS)

The mechanism of plastic deformation of martensite of a series of hardened steels (N18, 20KhG, 50KhFA and others) during tempering under tension and the role of residual internal microstresses and phase transformations are studied. It is shown that martensite low resistance to small plastic deformations during tempering under tension which is usually associated with phase transformations depends as well on the level of residual internal microstresses in the martensite structure. The decrease of resistance to deformation in the course of the decomposition of a solid solution is due to weakening of martensitic matrix because of carbon departure from the solid solution and carbide coarsening. An assumption is made that martensite plastic deformation during tempering under tension is realized at the expense of the directed microplastic deformation in the regions of higher concentration of internal stresses

230

Magnetic nondestructive technology for detection of tempered martensite embrittlement  

Energy Technology Data Exchange (ETDEWEB)

A nondestructive eddy current technique is used to evaluate tempered martensite embrittlement in 4340 AISI steels after quench and tempering in the range 240-550 Degree-Sign C. A relation between the responses of the magnetic induction (normalized impedance of the coil) and destructive Charpy impact test results has been established. The study shows that the eddy current method could be used to separate brittle parts due to the microstructure changes. - Highlights: Black-Right-Pointing-Pointer Occurrence of tempered martensite embrittlement in 4340 AISI steels was evaluated. Black-Right-Pointing-Pointer A reliable relation between EC output and Charpy impact test results was obtained. Black-Right-Pointing-Pointer EC technique was used to separate brittle parts due to the microstructure changes.

Kashefi, Mehrdad; Rafsanjani, Ali [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Kahrobaee, Saeed, E-mail: Saeed_kahrobaee@yahoo.com [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of); Alaee, Moeen [Department of Materials Science and Metallurgical Engineering, Engineering Faculty, Ferdowsi University of Mashhad, Mashhad (Iran, Islamic Republic of)

2012-11-15

231

Moessbauer spectroscopy analysis on a tempered martensitic 9% Cr steel  

International Nuclear Information System (INIS)

We report an analysis by means of Moessbauer spectroscopy, on a 9% Cr steel submitted to a tempering process at 780 deg. C. Spectra of several samples with different tempering times obtained at room temperature are fitted, and a study on existent phases is made. From the former analysis, we infer the existence of different neighbors of the Fe atom governed by the concentration of alloying elements. In particular, we analyze the behavior of Cr, as the main substitutional atom. An additional measurement of samples at low velocities is made, aiming to reveal the existence of precipitated carbides. Finally a comparison between samples is performed, in order to obtain a detailed study of the effect of tempering time on hyperfine parameters.

232

Resistance to softening during tempering of pearlitic and martensitic steels  

International Nuclear Information System (INIS)

Investigated are 40Kh4MBF, 40Kh4M1V3F, 50KhGSVF, 50KhGVF, and 15KhNMFA commercial steels. It is shown that the influence character of transformations taking place in carbide phase and in a solid solution of different steels (medium-alloy martensitic, low-alloy medium-carbon pearlitic and low-carbon low-alloy pearlitic) on their resistance to softening at tempering is the same (when process kinetics differs greatly). Steel softening at tempering is braked in such cases when, resulting from thermal treatment preceding long-term tempering, such carbide phase (type, distribution, dimensions) and such character of its interaction with solid solution are obtained which will be more stable under the following long-term heating

233

Radiation processing of temperate fruits of Kashmir valley  

International Nuclear Information System (INIS)

Kashmir valley is famous for its temperate horticulture. Main temperate fruits grown commercially in the valley include apple, pear, peach, plum, cherry, strawberry and apricot. These fruits being perishable and susceptible to microbial spoilage, have a short shelf-life. The short shelf-life in an impediment in their transportation and marketing and results in huge losses. Study was carried out at NRL, Srinagar to investigate the effect of gamma irradiation on the keeping quality of most of these fruits. The effect of gamma irradiation alone and in combination with other techniques like controlled low temperature storage, edible polysaccharide coating and calcium chloride treatment was studied in detail. The results revealed that there is a great potential for the use of radiation in extending the storage life of most of the temperate fruits produced in the valley of Kashmir. (author)

234

The Combinatorial Game Theory of Well-Tempered Scoring Games  

CERN Document Server

We consider the class of "well-tempered" integer-valued scoring games, which have the property that the parity of the length of the game is independent of the line of play. We consider disjunctive sums of these games, and develop a theory for them analogous to the standard theory of disjunctive sums of normal-play partizan games. We show that the monoid of well-tempered scoring games modulo indistinguishability is cancellative but not a group, and we describe its structure in terms of the group of normal-play partizan games. We also classify Boolean-valued well-tempered scoring games, showing that there are exactly seventy, up to equivalence.

Johnson, Will

2011-01-01

235

Genetic structure of Leptopilina boulardi populations from different climatic zones of Iran  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Abstract Background The genetic structure of populations can be influenced by geographic isolation (including physical distance) and ecology. We examined these effects in Leptopilina boulardi, a parasitoid of Drosophila of African origin and widely distributed over temperate and (sub) tropical climates. Results We sampled 11 populations of L. boulardi from five climatic zones in Iran and measured genetic differentiation at nuclear (Amp...

Jm, Alphen Jacques; Seyahooei Majeed; Kraaijeveld Ken

2011-01-01

236

Ultra low carbon bainitic (ULCB) steels after quenching and tempering  

International Nuclear Information System (INIS)

The mechanical and Charpy V impact strength properties of new advanced ultra low carbon bainitic (ULBC) steels after water quenching and tempering (WQT) have been investigated. Their chemical compositions are given. The nine continuous cooling transformation diagrams (CCT) of the new ULCB steel grades have been established. The CCT diagrams for ULCBNi steels containing 9% Ni - grade 10N9 and 5% Ni - grade HN5MVNb are given. The comparison between CCT diagrams of 3.5%Ni + 1.5%Cu containing steels grade HSLA 100 and HN3MCu is shown. The effect of the increase in carbon and titanium contents in the chemical composition of ULCBMn steels 04G3Ti, 06G3Ti and 09G3Ti on the kinetics of phase transformations during continuous cooling is presented by the shifting CCT diagrams. The Charpy V impact strength and brittle fracture occurence curves are shown. The effect of tempering temperature on tensile properties of WQT HN3MCu steel is shown and Charpy V impact strength curves after different tempering conditions are shown. The optimum tempering temperatures region of HN3MCu steel for high Charpy V impact toughness at law temperatures - 80oC(193 K) and -120oC(153 K) is estimated. The effect of tempering temperature on mechanical properties of HN5MVNb steel is given. The low temperature impact Charpy V toughness of HN5MVNb steel is shown. The optimum range of tempering temperature during 1 hour for high toughness of WQT HN5MVNb steel is gi high toughness of WQT HN5MVNb steel is given. HN3MCu and HN5MVNb steels after WQT have high yield strength YS?690 MPa and high Charpy V impact toughness KV?80 J at -100oC (173K) and KCV?50 J/cm2 at - 120oC (153K) so they may be used for cryogenic applications

237

Temperate Ice Under Jakobshavn Isbrae and Other Greenland Glaciers  

Science.gov (United States)

Jakobshavn Isbrae, western Greenland's largest outlet glacier, drains 6.5% of the ice sheet's area and therefore may be poised to make rapid contributions to global sea level rise. Indeed, in the late 1990s the glacier doubled in speed as its floating ice tongue disintegrated. Driving stresses up to 300 kPa suggest that a considerable amount of ice deformation combines with basal sliding to produce Jakobshavn's fast speed. Boreholes and overturned icebergs have indicated the existence of a soft, temperate layer at the bottom of the ice, where shear deformation would be concentrated. The thickness and water content of the temperate ice layer determine how much of the motion it can provide. While we focus on Jakobshavn, we also apply our analysis to other Greenland outlet glaciers. This project uses an implicit finite-difference model to compute the temperate ice thickness and water content along multiple flowlines feeding Jakobshavn Isbrae and other Greenland glaciers, in an effort to identify the mechanisms for their rapid movement. In contrast to previous modeling studies, which chose ice velocities in order to match partial temperature profiles measured in boreholes, our model is constrained by satellite-observed surface velocities. The model calculates the temperature field and determines the sliding and internal deformation velocities, constrained by the velocity measurements, to make a self-consistent balance. Feedbacks between temperature, water content, and viscosity allow the temperate shear layer to evolve. Our model results for temperate ice thickness under Jakobshavn (150-300 meters) agree with previous estimates (100-700 meters) and recent observations (30 and 200-250 meters). This model is well suited for glaciers with deeply eroded bedrock troughs. Forthcoming observational campaigns such as NASA's IceBridge program will produce detailed basal topography data for other Greenland outlet glaciers. As these data come online, we will model the temperate ice thickness under Greenland glaciers where field studies of deep ice temperature have not been done.

Poinar, K. E.; Joughin, I. R.

2010-12-01

238

Tempering effects on a martensitic high carbon steel  

International Nuclear Information System (INIS)

We study the effect of tempering on a martensitic steel containing 1.23 wt.% carbon, in the temperature range 300-800 K, correlating the results obtained by measurements of thermoelectric power (TEP), Young's modulus, calorimetry, nanoindentation, and the observations by transmission electron microscopy (TEM). Two tempering stages are observed, one between 350 and 430 K, and the other between 470 and 550 K. They are attributed to two stages of carbon precipitation. The evolution of Young's modulus, TEP, and hardness is mainly attributed to the change of the amount of interstitial carbon in iron

239

The Combinatorial Game Theory of Well-Tempered Scoring Games  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We consider the class of "well-tempered" integer-valued scoring games, which have the property that the parity of the length of the game is independent of the line of play. We consider disjunctive sums of these games, and develop a theory for them analogous to the standard theory of disjunctive sums of normal-play partizan games. We show that the monoid of well-tempered scoring games modulo indistinguishability is cancellative but not a group, and we describe its structure i...

Johnson, Will

2011-01-01

240

Winter Survival of Pratylenchus scribneri.  

Science.gov (United States)

Population densities of Pratylenchus scribneri in a Plainfield loamy sand soil were sampled from 1 October to 1 May for 4 years. From May to October of each year, the site was planted to Russet Burbank potato and Wis 4763 corn. Percentages of change in population densities of nematodes were computed on the basis of number of nematodes present on 1 October. The decline of P. scribneri between growing seasons was nonlinear, with most mortality occurring in the autumn before the soil froze. Winter survival, defined as the percentage of change in population densities from 1 October to 1 May the following year, ranged from 50 to 136% for nematodes in corn plots and from 15 to 86% for nematodes in potato plots. There was no difference in survival of nematodes of different life stages or among root and soil habitats. Winter survival of nematodes was density-dependent in 3 of 4 years in corn plots and in 1 of 4 years in potato plots. Although predators were present, their abundance was not correlated with the winter survival of nematodes. Cumulative and average snow cover was correlated with the survival of nematodes associated with corn but not with potato. No relationships between other climatic factors and survivorship were detected. PMID:19283113

Macguidwin, A E; Forge, T A

1991-04-01

 
 
 
 
241

46 CFR 54.25-25 - Welding of quenched and tempered steels (modifies UHT-82).  

Science.gov (United States)

... false Welding of quenched and tempered steels (modifies UHT-82). 54.25-25 Section 54.25-25 Shipping ...25-25 Welding of quenched and tempered steels (modifies UHT-82). (a) The qualification of welding...

2010-10-01

242

Snow surface energy and mass balance in a warm temperate climate mountain  

Science.gov (United States)

In warm temperate mountain regions where water is often scarce vapor losses from the snow-surface can substantially limit snowmelt. Therefore, understanding the key snow dynamic processes that affect water availability in these mountains is essential. We studied the snowpack energy and mass balance in Mt. Hermon, Israel using a comprehensive field campaign during 2010/11. We analyzed the snowpack energy and mass balance during the winter of 2010/11 in a Deep Snow Patch (DSP), and in the Bulan valley experiment area (BVEA), where both windswept locations and lee-side (deep snowpack) locations were examined. We applied for this analysis an energy and mass balance snow model that was forced by input from two meteorological stations. The calibration of the model for the DSP and BVEA was based on surveyed snow water equivalent data, and melting cycles that were measured with time-lapse cameras, respectively. Using a step function to describe wind speed over the DSP we showed that the turbulent fluxes were influenced by changes in snowpack height. The turbulent fluxes were found as the dominant energy fluxes at the snow-surface. During winter, vapor losses varied between 46% and 82% of the total ablation. Consequently, latent heat flux consumed much of the available energy at the snow-surface, greatly limiting melting rate to 1 mm day-1. During spring, vapor flux was positive which enhanced condensation, resulting in an average melting flux of 86 mm day-1. The spatial variation in the vapor flux at the BVEA due to terrain orientation yield variation in space of the available water at the bottom of the snowpack.

Sade, Rotem; Rimmer, Alon; Litaor, M. Iggy; Shamir, Eylon; Furman, Alex

2014-11-01

243

CO2 flux in a cool-temperate deciduous forest (Quercus mongolica of Mt. Nam in Seoul, Korea  

Directory of Open Access Journals (Sweden)

Full Text Available The Namsan Ecological Tower Site based on a flux tower was equipped with eddy covariance and automatic opening/closing chamber systems to collect long-term continuous measurements of CO2 flux, such as the net ecosystem exchange(NEE and soil CO2 efflux in a cool-temperate Quercus mongolica forest. The mean concentrations of atmosphericCO2 (705 mg/m3 during the summer were smaller than those measured (770 mg/m3 during the winter. The mean CO2flux during the summer period was negative (-0.34 mg m-2 s-1, while that during the winter period was positive (0.14 mgm-2 s-1. CO2 was deposited from the atmosphere to the surface in the summer. The daily mean value of soil CO2 effluxincreased from spring to summer. The seasonal pattern in the rate of soil CO2 efflux tightly followed the seasonal patternin soil temperatures. The Q10 values for soil CO2 efflux varied in a range from 2.12 to 3.26, and increased with increasingsoil depth. The maximum value of total carbon uptake (i.e., NEE during the growing season was -8 g CO2 m-2 day-1. At thesame time, the rate of soil CO2 efflux was 6.9 g CO2 m-2 day-1. The amplitude of flux variations in NEE was approximately14% larger than those in soil CO2 efflux. These results suggest that in cool-temperate regions of the Korean peninsula,the forest ecosystem of Q. mongolica may have a larger atmospheric CO2 uptake, due primarily to its high photosyntheticcapacity and low ecosystem respiration.

Seung Jin Joo

2011-03-01

244

Brooding in a temperate zone land snail: seasonal and regional patterns  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The goal of this study is to assess if the reproductive strategy of a brooding land snail shifts along a climatic gradient. We focused on the following traits: timing and length of the reproductive season, brood size, ontogenetic dynamics of embryos, and reproductive mode (viviparity versus egg-laying). We dissected the central European door snail Alinda biplicata, collected monthly from eight populations covering the oceaniccontinental climatic gradient within the species’ distribution ran...

Sulikowska-drozd, A.; Maltz, T. K.; Kappes, H.

2013-01-01

245

[Actinomycete complexes in the rhizosphere of winter rye on soddy podzolic soil].  

Science.gov (United States)

The structure of actinomycete complexes in the rhizosphere of winter rye (Secale cereale L.) varieties originating from different ecosystems and geographical zones was studied in field experiments on soddy podzolic soil. In addition to streptomycetes, the complexes studied contained actinomycetes of the genera Micromonospora and Streptosporangium, represented at high occurrence and comparable abundance rates. The rhizosphere of most of the studied rye varieties was dominated by micromonosporas. The antifungal potential of mycelial prokaryotes associated with winter rye was assessed. The taxonomic and functional structure of actinomycete complexes was shown to be similar in rye varieties originating from the nonchernozem zone of Russia. However, the actinomycete complex proved to be much different in the rye variety that developed in the steppe zone of the lower Volga region. PMID:15938405

Shirokikh, I G; Merzaeva, O V

2005-01-01

246

Temper Tantrums: A Developmental Perspective from a Clinical Psychologist.  

Science.gov (United States)

Addresses questions such as why children have temper tantrums, how teachers and parents should respond to a demanding child, and how behavioral outbursts can be used to help children deal constructively with powerful emotions. Distinguishes between normal and severe tantrums, and conceptualizes and suggests intervention techniques. (BAC)

Proffer, Andrew A.

1995-01-01

247

Microstructure properties of tempered D6ac steel  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer We evaluated microstructure properties of tempered D6ac steel. Black-Right-Pointing-Pointer The forming process has a high microhardness of martensite phase at surface layer. Black-Right-Pointing-Pointer XRD spectra observed that the residual austenite and/or mixed structures of ferrite with the precipitation of carbides. Black-Right-Pointing-Pointer Ferrite decreased and that of carbon and chromium elements increased upon increasing the tempering temperature. - Abstract: The aim of this study was to determine the microstructure and surface mechanical properties of tempered D6ac. The obtained microstructures exhibited a number of misfit dislocations from work hardening, with the degree of disorder dislocation decreasing gradually upon increasing the temperature at 650 Degree-Sign C. XRD spectra observed that the residual austenite and/or mixed structures of ferrite with the precipitation of carbides at 650 Degree-Sign C will result in a softer state than that of the room temperature specimen. In addition, the forming process has a high microhardness of martensite phase at surface layer, subjected to heat treatment until a stable state is achieved. The content of ferrite atoms decreased and that of carbon and chromium elements increased upon increasing the tempering temperature.

Lian Derming, E-mail: lianderming@gmail.com [Department of Mechanical Engineering, Chin-Yi University of Technology, Taichung 411, Taiwan (China)

2013-01-01

248

Growth, flowering, and population dynamics of temperate Western Australian seagrasses  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Quantification of module size, leaf, rhizome and clonal growth, flowering intensity and shoot population dynamics of 7 temperate Western Australian seagrasses (Amphibolis antarctica, A. griffithii, Posidonia australis, P. sinuosa, P. angustifolia, Heterozostera tasmanica, Thalassodendron pachyrhizum) developing 8 monospecific stands reveals that these plants have different plant morphologies, display a wide repertoire of growth patterns, and exhibit substantial variability in their capacity t...

Marba?, Nu?ria; Walker, Diana I.

1999-01-01

249

Management strategy and options for the Tweedsmuir-Entiako Caribou winter range. Land management report No. 83  

Energy Technology Data Exchange (ETDEWEB)

Proposed logging on the winter ranges of woodland caribou in west-central British Columbia precipitated the need for a timber harvesting strategy that is compatible with caribou winter habitat requirements. This report describes the methods used in developing the management strategy for the Tweedsmuir-Entiako caribou winter range; describes each caribou management zone and summarizes the caribou habitat and current timber supply characteristics of each; and discusses the six management options and their implications to woodland caribou and to the timber supply.

Cichowski, D.B.; Banner, A.

1993-01-01

250

Synoptic influence on winter temperature and precipitation in western Montana  

Science.gov (United States)

In this dissertation, synoptic climatology is used to investigate the spatial variability of winter temperature and precipitation over western Montana. Statistical description of winter precipitation in the region shows significant variability in both spatial and temporal characteristics. Using rotated principal component analysis (RCPA) four distinct regions, that are physically reasonable, reveal the effect of the dominant airmasses and topography over the region. These regions are the northwestern part which show mainly the influence of northwesterly flow from the Pacific and of the topography of the rocky mountains; the mostly dry eastern part influenced mainly by the rain-shadow zone of the Rockies, the area between the rain-shadow zone and the moist western area where the precipitation pattern can be explained by storms which occur from the edge of fronts that move from Alberta down into the high plains; and the southern part region which has very high elevations but and for the most part characterized by the effect of the mountain ranges in northern Wyoming on the southerly flow from the gulf. From a 4 x 5 array of self organizing maps of daily winter 700mb geopotential height, patterns to winter precipitation show a strong influence of the westerly airmasses as main contributor of precipitation. The spatial analysis of precipitation for each of the synoptic types also shows the effect of topography. This makes the northwestern part of the region the major source of snowpack for the region. Using the results from the circulation patterns, the influence of synoptic types on winter temperature and precipitation are discussed by analyzing the variability of lapse rate and orographic rate with synoptic types. The results show that lapse rates and orographic rates vary significantly with synoptic types over western Montana. Estimates of temperature and precipitation using MTCLIM shows that synoptic types have significant influence on our ability to predict these elements in mountain regions. More precise values of lapse rates and orographic rates would predict temperature and precipitation better than long term averages of lapse rates and generalized isohyetal values.

Goshit, Sunday Damina

251

Moderate warming in microcosm experiment does not affect microbial communities in temperate vineyard soils.  

Science.gov (United States)

Changes in the soil microbial community structure can lead to dramatic changes in the soil ecosystem. Temperature, which is projected to increase with climate change, is commonly assumed to affect microbial communities, but its effects on agricultural soils are not fully understood. We collected soil samples from six vineyards characterised by a difference of about 2 °C in daily soil temperature over the year and simulated in a microcosm experiment different temperature regimes over a period of 1 year: seasonal fluctuations in soil temperature based on the average daily soil temperature measured in the field; soil temperature warming (2 °C above the normal seasonal temperatures); and constant temperatures normally registered in these temperate soils in winter (3 °C) and in summer (20 °C). Changes in the soil bacterial and fungal community structures were analysed by automated ribosomal intergenic spacer analysis (ARISA). We did not find any effect of warming on soil bacterial and fungal communities, while stable temperatures affected the fungal more than the bacterial communities, although this effect was soil dependent. The soil bacterial community exhibited soil-dependent seasonal fluctuations, while the fungal community was mainly stable. Each soil harbours different microbial communities that respond differently to seasonal temperature fluctuations; therefore, any generalization regarding the effect of climate change on soil communities should be made carefully. PMID:24435544

Corneo, Paola Elisa; Pellegrini, Alberto; Cappellin, Luca; Gessler, Cesare; Pertot, Ilaria

2014-04-01

252

Experimental evaluation of thermal and energy performance of temperate green roofs: a case study in Beijing  

Science.gov (United States)

An experimental evaluation of thermal and energy performance of temperate green roofs was carried out by thermal and meteorological observation and energy budget modeling using a setup of green roof in Beijing urban area. From both the yearly and daily temperature trends, the green roof could effectively damp down the undulation of roof surface temperature comparing with the conventional one. As an insulating screen, the green roof abated the amplitude of temperature by 9.0 in winter and 9.1 °C in summer, respectively. Under different cloud conditions, the green roof in summer time resulted in decreases in sensible heat and heat flux by 125.3W m-2 and 32.0 W m-2, respectively, on daily average comparing with the conventional one. Based on the energy budget analyses, under an assumptive scenario of 50% roof-greening in Beijing, a total of 34.1 PJ of sensible heat and 8.7 PJ of heat flux would be decreased for a summer period of 90 days. This study demonstrated that green roof, serving as an insulating screen to building top in comparison with the conventional roof, proved thermal improving effect in building scale and high energy saving potential for urban development.

Sun, T.; Institute of Hydrology; Water Resources

2011-12-01

253

Groundwater flow modelling of periods with temperate climate conditions - Forsmark  

International Nuclear Information System (INIS)

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Forsmark site during temperate conditions; i.e. from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 12,000 AD. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a hydrogeological base case (reference case conceptualisation) and then in an examination of various areas of uncertainty within the current understanding by a series of model variants. The hydrogeological base case models at three different scales, 'repository', 'site' and 'regional', make use of continuous porous medium (CPM), equivalent continuous porous medium (ECPM) and discrete fracture network (DFN) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

254

Groundwater flow modelling of periods with temperate climate conditions - Forsmark  

Energy Technology Data Exchange (ETDEWEB)

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different climate conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Forsmark site during temperate conditions; i.e. from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 12,000 AD. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a hydrogeological base case (reference case conceptualisation) and then in an examination of various areas of uncertainty within the current understanding by a series of model variants. The hydrogeological base case models at three different scales, 'repository', 'site' and 'regional', make use of continuous porous medium (CPM), equivalent continuous porous medium (ECPM) and discrete fracture network (DFN) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Swan, David (Serco Technical Consulting Services (United Kingdom)); Marsic, Niko (Kemakta Konsult AB (Sweden)); Follin, Sven (SF GeoLogic AB (Sweden))

2010-11-15

255

Southern ocean winter mixed layer  

Science.gov (United States)

Austral winter 1986 observations from the Polarstern along the Greenwich meridian from the ice edge to the Antarctic margin show the mixed layer beneath the winter sea ice cover to be significantly depressed in oxygen saturation. Incorporation of Weddell Deep Water (WDW) into the winter mixed layer, responsible for this undersaturation, also introduces heat and salinity into the surface layer which strongly influences the mixed layer, sea-air exchanges and sea ice formation processes. The total WDW transfer into the mixed layer averages 45 myr-1, implying a residence time for the surface water of 2.5 years. The associated winter heat flux is 41 W m-2, which limits ice thickness to about 0.55 m, agreeing quite well with observations. The air temperatures during the cruise are just sufficient to remove the WDW heat input in the presence of observed ice thickness and concentration. This suggests that the sea ice cover and WDW heat input into the mixed layer are in approximate balance by midwinter. The annual heat flux from WDW to the surface layer, and hence into the atmosphere, is estimated as 16 W m-2. Extrapolation of the Greenwich meridian WDW entrainment value to the full circumpolar 60°-70°S belt yields total up welling of 24×106 m3 s-1. Similar extrapolation of the heat flux value gives a circumpolar total of 2.8 × 1014 W. As a consequence of circulation/topography interaction, the Maud Rise water column stands out as an anomaly relative to the surrounding region, with a significantly more saline and dense mixed layer. Below the mixed layer the water column over the crest of the rise is identical to that over the flanks if the latter water column is upwelled by 400 m. This uplifting is believed to be a response of the upstream flow encountering the rise. Increased upstream flow would be expected to increase Maud Rise upwelling and the dependent salinity (density) of the mixed layer. Slight increases in the mixed layer density could trigger a convective mode and generation of a polynya. It is hypothesized that spin-up of the Weddell Gyre's barotropic circulation induced by an increase of the regional wind stress curl would enhance the probability of polynya development over Maud Rise.

Gordon, Arnold L.; Huber, Bruce A.

1990-07-01

256

Effect of temper on environmental fatigue crack propagation in 7000-series aluminum alloys  

Energy Technology Data Exchange (ETDEWEB)

In contrast to stress corrosion, the effect of overaging temper on environmental fatigue crack propagation rate in the 7000-series aluminum alloy/aqueous-chloride solution system is nil, moderately beneficial, or detrimental depending on loading frequency. For both peak and overaged AA7075 plate, Paris regime fatigue crack growth rates are accelerated up to 10-fold by cyclic loading in 3.5% NaCl solution compared to fatigue in moist air for the SL-crack orientation. Crack growth is intersubgranular for the T6 microstructure, but transgranular-brittle for the T7 case. Cracking at low f is dominated by corrosion product induced crack closure that is enhanced by overaging. At intermediate to high f, environmental fatigue is due to hydrogen embrittlement and rate limited by H diffusion over a crack tip process zone distance established by local stress. The relationship between plateau crack growth rate and critical frequency for f-dependent EFCP is predicted by a H diffusion model. Plateau regime transgranular-brittle EFCP in overaged AA7075 is slower than intersubgranular cracking in the T6 microstructure, but persists to higher f{sub CRIT}, requiring either rapid H diffusion or reduced crack tip H for process zone embrittlement of the overaged case. (orig.)

Gasem, Z.M.; Gangloff, R.P. [Virginia Univ., Charlottesville, VA (United States). Dept. of Mater. Sci. and Eng.

2000-07-01

257

Late winter temperature response to large tropical volcanic eruptions in temperate western North America: Relationship to ENSO phases  

Science.gov (United States)

February-March temperature reconstructions in western North America from 1500-1980 in the Common Era (CE) are used to evaluate, from a regional perspective, the hypothesis that radiative forcing by large tropical volcanic eruptions induces a tendency in the climate system towards an early post-event El Niño (EN) response followed by a delayed La Niña (LN) response. Post-event spatial composites using superposed epoch analysis (SEA) detect indications for an EN-like pattern in post-event Years 1-2; this result, however, is sensitive to the set of eruptions evaluated. Highly significant LN-like patterns are also observed for two eruptions during Year 1. In contrast, a clear and unique LN-like response is found in both evaluated eruption sets during Years 3-5; Year 3 in particular represents the time of strongest post-event response. No significant EN-like patterns occur during these years. The relative homogeneity of the SEA response for each post-event year is evaluated in terms of the ratio of the amplitude of the SEA composite to its standard deviation across the eruption events. In relation to the same metric determined from random-event-year SEAs, these signal-to-noise ratios are most highly significant in the portions of the domain with the strongest anomalies in Years 1-5, especially Year 3. The signal-to-noise ratios tend towards uniformly low and insignificant values beyond the first half-decade after the eruption, indicating generally reduced coherence across events. In relation to the larger-scale circulation, post-eruption 500mb February-March geopotential height composites from the 20th Century Reanalysis show ENSO-type features that are largely consistent with the SEA results from the primary eruption set during Year 1, but are inconsistent with the EN-like pattern exhibited by the second eruption set during Years 1-2. In Year 3, the pressure composite over North America and the adjacent Pacific and Atlantic is strongly LN-like, consistent with all SEA results; similarly, weakening coherence across events as time progresses beyond Year 3 is also consistent with more variable pressure composites noted after that time. The relatively robust character of the delayed LN-like response is evaluated in terms of the dynamic rebound of the climate system towards its initial energy balance as the radiative impact of immediate post-eruption aerosol cooling dissipates. The LN-like SEA temperature response in Years 3-5 exhibits a slight shift of its southern warm anomaly to the north and west relative to pure composite LN conditions, which is detected as a specifically post-eruption feature in the region.

Wahl, Eugene R.; Diaz, Henry F.; Smerdon, Jason E.; Ammann, Caspar M.

2014-11-01

258

Phytoclimate of winter rye stands  

Energy Technology Data Exchange (ETDEWEB)

The present study describes the microclimate within a winter rye (Secale cereale) stand compared to that above a bare soil at the same height. It is focused on air temperature and humidity. The study is based on long-term measurements (1981-1999) at 0.2 m above ground in the agrometeorological field experiment at Berlin-Dahlem (Humboldt-University of Berlin). The microclimate within a winter rye stand differs significantly from that above a bare soil. Temperature and actual vapour pressure differences between both locations depend on the developmental stage of the plants as well as the time of the day. Their influence is so strong that a detailed analysis of the microclimate makes it necessary to break down the growing time of crop into several developmental periods. So, it was possible to describe and explain the characteristics of the phytoclimate in a relatively detailed and comprehensive manner. Thereby the assessment of potential damages caused by pests and diseases within crop stands becomes more precise. (orig.)

Wittchen, U. [Federal Biological Research Centre for Agriculture and Forestry, Kleinmachnow (Germany); Chmielewski, F.M. [Humboldt-Univ. of Berlin, Faculty of Agriculture and Horticulture, Berlin (Germany)

2005-04-01

259

Second generation sequencing and morphological faecal analysis reveal unexpected foraging behaviour by Myotis nattereri (Chiroptera, Vespertilionidae) in winter  

DEFF Research Database (Denmark)

BACKGROUND: Temperate winters produce extreme energetic challenges for small insectivorous mammals. Some bat species inhabiting locations with mild temperate winters forage during brief inter-torpor normothermic periods of activity. However, the winter diet of bats in mild temperate locations is studied infrequently. Although microscopic analyses of faeces have traditionally been used to characterise bat diet, recently the coupling of PCR with second generation sequencing has offered the potential to further advance our understanding of animal dietary composition and foraging behaviour by allowing identification of a much greater proportion of prey items often with increased taxonomic resolution. We used morphological analysis and Illumina-based second generation sequencing to study the winter diet of Natterer's bat (Myotis nattereri) and compared the results obtained from these two approaches. For the first time, we demonstrate the applicability of the Illumina MiSeq platform as a data generation source for bat dietary analyses. RESULTS: Faecal pellets collected from a hibernation site in southern England during two winters (December-March 2009-10 and 2010-11), indicated that M. nattereri forages throughout winter at least in a location with a mild winter climate. Through morphological analysis, arthropod fragments from seven taxonomic orders were identified. A high proportion of these was non-volant (67.9% of faecal pellets) and unexpectedly included many lepidopteran larvae. Molecular analysis identified 43 prey species from six taxonomic orders and confirmed the frequent presence of lepidopteran species that overwinter as larvae. CONCLUSIONS: The winter diet of M. nattereri is substantially different from other times of the year confirming that this species has a wide and adaptable dietary niche. Comparison of DNA derived from the prey to an extensive reference dataset of potential prey barcode sequences permitted fine scale taxonomic resolution of prey species. The high occurrence of non-volant prey suggests that gleaning allows prey capture at low ambient temperatures when the abundance of flying insects may be substantially reduced. Interesting questions arise as to how M. nattereri might successfully locate and capture some of the non-volant prey species encountered in its faeces. The consumption of lepidopteran larvae such as cutworms suggests that M. nattereri eats agricultural pest species.

Hope, Paul R; Bohmann, Kristine

2014-01-01

260

Isotopic variation across the Audubon's-myrtle warbler hybrid zone.  

Science.gov (United States)

Differences in seasonal migratory behaviours are thought to be an important component of reproductive isolation in many organisms. Stable isotopes have been used with success in estimating the location and qualities of disjunct breeding and wintering areas. However, few studies have used isotopic data to estimate the movements of hybrid offspring in species that form hybrid zones. Here, we use stable hydrogen to estimate the wintering locations and migratory patterns of two common and widespread migratory birds, Audubon's (Setophaga auduboni) and myrtle (S. coronata) warblers, as well as their hybrids. These two species form a narrow hybrid zone with extensive interbreeding in the Rocky Mountains of British Columbia and Alberta, Canada, which has been studied for over four decades. Isotopes in feathers grown on the wintering grounds or early on migration reveal three important patterns: (1) Audubon's and myrtle warblers from allopatric breeding populations winter in isotopically different environments, consistent with band recovery data and suggesting that there is a narrow migratory transition between the two species, (2) most hybrids appear to overwinter in the south-eastern USA, similar to where myrtle warblers are known to winter, and (3) some hybrid individuals, particularly those along the western edge of the hybrid zone, show Audubon's-like isotopic patterns. These data suggest there is a migratory divide between these two species, but that it is not directly coincident with the centre of the hybrid zone in the breeding range. We interpret these findings and discuss them within the context of previous research on hybrid zones, speciation and migratory divides. PMID:24779396

Toews, D P L; Brelsford, A; Irwin, D E

2014-06-01

 
 
 
 
261

Temper outbursts in paediatric obsessive-compulsive disorder and their association with depressed mood and treatment outcome.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Temper outbursts in youth with obsessive-compulsive disorder (OCD) are a common source of concern, but remain poorly understood. This study examined a set of hypotheses related to: (a) the prevalence of temper outbursts in paediatric OCD, (b) the associations of temper outbursts with OCD severity and depressive symptoms; and (c) the influence of temper outbursts on treatment response.

Krebs, G.; Bolhuis, K.; Heyman, I.; Mataix-cols, D.; Turner, C.; Stringaris, A

2013-01-01

262

[Distribution characteristics of benthic algae in intertidal zone of Ma' an Archipelago of Zhejiang Province].  

Science.gov (United States)

Based on the survey of benthic algae in the intertidal zone of Ma' an Archipelago from March to July 2007, the algal species composition, distribution, and temperature feature were studied. The dominant algal species in the study area were preliminarily analyzed by using similarity indices (S(c)) and index of relative importance (IRI(c)). A total of 31 species sampled in sublittoral area were identified, among which, 7 species of 5 genera belonged to Chlorophyta, 8 species of 5 genera belonged to Phaeophyta, and 16 species of 14 genera belonged to Rhodophyta. Topical and selective distribution species influenced by wave and tide were identified in the intertidal zone. Ulva pertusa and Sargassum thunbergii were found in all survey area. Rhodophyta was the dominant species, with the occurring frequency being up to 61.1%, and Chlorophyta showed quite uniformed horizontal distribution. In addition, 81% of sampled species were from low-tide zone, and some were extended from mid-tide zone to low-tide zone. The composition comparability between mid-tide and low-tide species was 0.47, and the convergence effect in mid-tide and low-tide zone was higher than that in high-tide and mid-tide zone. The sublittoral area of Ma' an Archipelago showed obvious vertical zoning character, with temperate species being absolute abundant, and the warm-water species dominant. The marine floral texture of Ma' an Archipelago belongs to warm temperate-subtropical transitional marine flora. PMID:19123370

Zhang, Shou-Yu; Liang, Jun; Wang, Zhen-Hua; Wang, Kai

2008-10-01

263

Temperature responses of tropical to warm temperate Cladophora species in relation to their distribution in the North Atlantic Ocean  

Science.gov (United States)

The relationship between distribution boundaries and temperature responses of some North Atlantic Cladophora species (Chlorophyta) was experimentally examined under various regimes of temperature, light and daylength. Experimentally determined critical temperature intervals, in which survival, growth or reproduction was limited, were compared with annual temperature regimes (monthly means and extremes) at sites inside and outside distribution boundaries. The species tested belonged to two phytogeographic groups: (1) the tropical West Atlantic group ( C. submarina: isolate from Curaçao) and (2) the amphiatlantic tropical to warm temperate group ( C. prolifera: isolate from Corsica; C. coelothrix: isolates from Brittany and Curaçao; and C. laetevirens: isolates from deep and shallow water in Corsica and from Brittany). In accordance with distribution from tropical to warm temperate regions, each of the species grew well between 20 30°C and reproduction and growth were limited at and below 15°C. The upper survival limit in long days was <35°C in all species but high or maximum growth rates occurred at 30°C. C. prolifera, restricted to the tropical margins, had the most limited survival at 35°C. Experimental evidence suggests that C. submarina is restricted to the Caribbean and excluded from the more northerly American mainland and Gulf of Mexico coasts by sporadic low winter temperatures in the nearshore waters, when cold northerly weather penetrates far south every few years. Experimental evidence suggests that C. prolifera, C. coelothrix and C. laetevirens are restricted to their northern European boundaries by summer temperatures too low for sufficient growth and/or reproduction. Their progressively more northerly located boundaries were accounted for by differences in growth rates over the critical 10 15°C interval. C. prolifera and C. coelothrix are excluded or restricted in distribution on North Sea coasts by lethal winter temperatures, again differences in cold tolerance accounting for differences in their distribution patterns. On the American coast, species were probably restricted by lethal winter temperatures in the nearshore and, in some cases, by the absence of suitable hard substrates in the more equable offshore waters. Isolates from two points along the European coast (Brittany, Corsica) of C. laetevirens showed no marked differences in their temperature tolerance but the Caribbean and European isolates of C. coelothrix differed markedly in their tolerance to low temperatures, the lethal limit of the Caribbean isolate lying more than 5°C higher (at ca 5°C).

Cambridge, M. L.; Breeman, A. M.; Kraak, S.; van den Hoek, C.

1987-09-01

264

Oxygenated polycyclic aromatic hydrocarbons and azaarenes in urban soils: a comparison of a tropical city (Bangkok) with two temperate cities (Bratislava and Gothenburg).  

Science.gov (United States)

Environmental conditions in the tropics favor the formation of polar polycyclic aromatic compound (polar PACs, such as oxygenated PAHs [OPAHs] and azaarenes [AZAs]), but little is known about these hazardous compounds in tropical soils. The objectives of this work were to determine (i) the level of contamination of soils (0-5 and 5-10 cm layers) from the tropical metropolis of Bangkok (Thailand) with OPAHs and AZAs and (ii) the influence of urban emission sources and soil properties on the distribution of PACs. We hypothesized that the higher solar insolation and microbial activity in the tropics than in the temperate zone will lead to enhanced secondary formation of OPAHs. Hence, OPAH to related parent-PAH ratios will be higher in the tropical soils of Bangkok than in temperate soils of Bratislava and Gothenburg. The concentrations of ?15OPAHs (range: 12-269 ng g(-1)) and ?4AZAs (0.1-31 ng g(-1)) measured in soils of Bangkok were lower than those in several cities of the industrialized temperate zone. The ?15OPAHs (r=0.86, ppartition coefficient did not explain the transport to the subsoil, indicating soil mixing as the reason for the polar PAC load of the lower soil layer. Data on PAC concentrations in soils of Bratislava and Gothenburg were taken from published literature. The individual OPAH to parent-PAH ratios in soils of Bangkok were mostly higher than those of Bratislava and Gothenburg (e.g. 9-fluorenone/fluorene concentration ratio was 12.2 ± 6.7, 5.6 ± 2.4, and 0.7 ± 02 in Bangkok, Bratislava and Gothenburg soils, respectively) supporting the view that tropical environmental conditions and higher microbial activity likely lead to higher OPAH to parent-PAH ratios in tropical than in temperate soils. PMID:24529396

Bandowe, Benjamin A Musa; Lueso, María Gómez; Wilcke, Wolfgang

2014-07-01

265

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.  

Science.gov (United States)

...Harbor Lobster Boat Race, Winter Harbor, ME. 100.109 Section 100.109 Navigation...Harbor Lobster Boat Race, Winter Harbor, ME. (a) Regulated area. The regulated area includes all waters of Winter Harbor, ME, within the following points (NAD...

2010-07-01

266

Geometric Brownian Motion with Tempered Stable Waiting Times  

Science.gov (United States)

One of the earliest system that was used to asset prices description is Black-Scholes model. It is based on geometric Brownian motion and was used as a tool for pricing various financial instruments. However, when it comes to data description, geometric Brownian motion is not capable to capture many properties of present financial markets. One can name here for instance periods of constant values. Therefore we propose an alternative approach based on subordinated tempered stable geometric Brownian motion which is a combination of the popular geometric Brownian motion and inverse tempered stable subordinator. In this paper we introduce the mentioned process and present its main properties. We propose also the estimation procedure and calibrate the analyzed system to real data.

Gajda, Janusz; Wy?oma?ska, Agnieszka

2012-08-01

267

Heavy tempering of large steel castings and forgings  

International Nuclear Information System (INIS)

When standard grade Cr-Mo-Ni low-alloy steels of high hardenability are employed for manufacture of large castings and forgings of high integrity, their composition can be modified by certain additions. In this article the various effects of Cr, Mo and V are dealt with on the basis of their influence on the properties of the steel grade BS 826M31. The effects of modification, to this steel by increasing the molybdenum content to 1,0% or additions of 0,2% and 0,4% vanadium, on stress relaxation, hardenability, reversible temper embrittlement (RTE), tempering resistance, embrittlement, chemical composition and charpy impact energy are illustrated. 11 refs., 13 figs., 2 tabs

268

Microstructure properties of tempered D6ac steel  

Science.gov (United States)

The aim of this study was to determine the microstructure and surface mechanical properties of tempered D6ac. The obtained microstructures exhibited a number of misfit dislocations from work hardening, with the degree of disorder dislocation decreasing gradually upon increasing the temperature at 650 °C. XRD spectra observed that the residual austenite and/or mixed structures of ferrite with the precipitation of carbides at 650 °C will result in a softer state than that of the room temperature specimen. In addition, the forming process has a high microhardness of martensite phase at surface layer, subjected to heat treatment until a stable state is achieved. The content of ferrite atoms decreased and that of carbon and chromium elements increased upon increasing the tempering temperature.

Lian, Derming

2013-01-01

269

Reversible temper brittleness on tensile tests at room temperature  

International Nuclear Information System (INIS)

Tensile tests were carried out on unnotched test pieces at room temperature and three strain rates: 2,5x10-4, 2,5x10-3 and 1,0x10-2 s-1 in a low alloy No-Cr-Mo steel to observe the variation in its mechanical properties with the occurrence of reversible temper brittleness. The brittle samples showed a sensitivity of 500C in a 48 hour heat treatment at 5000C. The tests showed that at the strain rate of 2,5x10-4 s-1 there are statistically significant differences between the elongations of the material in the brittle and the nonbrittle and regenerated states. A short review of reversible temper brittleness is given and a theory suggested for the mechanism

270

Simulation of Residual Stresses at Holes in Tempered Glass  

DEFF Research Database (Denmark)

This work presents a full 3D numerical study of the residual stresses in tempered (toughened) glass near holes using Narayanaswamy’s model for the tempering process. It is the objective of the paper to elucidate the influence on the minimal residual compressive stresses at holes from variations in: the far-field stress, plate thickness, hole diameter and the interaction between holes and edges and corners. The work presents novel results for the sensitivity of the residual stresses to geometric features and provides a design tool for estimating residual stresses at holes for different geometries. An example of how to extrapolate the results in terms of far-field stresses is given.

Nielsen, Jens Henrik; Olesen, John Forbes

2010-01-01

271

Production of methyl bromide in a temperate forest soil  

Science.gov (United States)

Field enclosure measurements of a temperate forest soil show net uptake of ambient methyl bromide (CH3Br), an important trace gas in both tropospheric and stratospheric ozone cycling. The net flux for 1999 was estimated to be -168 +/- 72 ?g CH3Br m-2 (negative indicates loss from the atmosphere). Individual enclosure flux measurements ranged from -4.0 to +3.3 ?g CH3Br m-2 d-1. Soil consumption of CH3Br was estimated from laboratory soil incubations. Production of CH3Br was calculated as the difference between net flux and predicted consumption. Fungi could be responsible for the production of CH3Br in this temperate forest soil.

Varner, Ruth K.; White, Marguerite L.; Mosedale, Cindy H.; Crill, Patrick M.

2003-05-01

272

Winter Olympics Physics and Biomechanics  

Science.gov (United States)

Many Winter Olympic sports are greatly dependent on technique, engineering, and/or gravity. For example, during luge, while gravity is accelerating the sled up to 80 mph down the track, the slider must use good technique to steer the sled and minimize air resistance. To excel in these type of sports, it is helpful to have a full appreciation of physics and biomechanics. Physics is a broad field which includes mechanics, electricity, magnetism, optics, etc., and biomechanics is the study of the mechanics of living systems. In the module we will use the sports of luge and figure skating to teach you four basic mechanical concepts: linear kinematics, linear dynamics, projectile motion, and conservation of angular momentum. In addition, we have developed a glossary which defines and illustrates all the physics terminology you will need to complete this module.

273

An empirical exploration of the world oil price under the target zone model  

International Nuclear Information System (INIS)

This paper investigates the behavior of the world oil price based on the first-generation target zone model. Using anecdotal data during the period of 1988-1999, we found that OPEC has tried to maintain a weak target zone regime for the oil price. Our econometric tests suggest that the movement of the oil price is not only manipulated by actual and substantial interventions by OPEC but also tempered by market participants' expectations of interventions. As a consequence, the non-linear model based on the target zone theory has very good forecasting ability when the oil price approaches the upper or lower limit of the band

274

An empirical exploration of the world oil price under the target zone model  

International Nuclear Information System (INIS)

This paper investigates the behavior of the world oil price based on the first-generation target zone model. Using anecdotal data during the period of 1988-1999, we found that OPEC has tried to maintain a weak target zone regime for the oil price. Our econometric tests suggest that the movement of the oil price is not only manipulated by actual and substantial interventions by OPEC but also tempered by market participants' expectations of interventions. As a consequence, the non-linear model based on the target zone theory has very good forecasting ability when the oil price approaches the upper or lower limit of the band. (author)

275

Recent observations of Jupiter's North North Temperate Belt Current B.  

Science.gov (United States)

An outbreak of thirteen spots in Jupiter's North North Temperate Belt Current B was observed in 1972. These have been measured and compared with measures of the two most previous outbreaks. The drift in longitude of a hypothetical source supports both Reese's original hypothesis of a subsurface source, and Solberg's observation that its period is close to that of System III. There is some evidence that long-enduring atmospheric features exist at lower, unobservable depths.

Minton, R. B.

1973-01-01

276

Radioecology of temperate coastal sand dunes: A synthesis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Temperate coastal sand dunes are amongst the most dynamic landscapes on earth, their evolution being mediated by both climatic and environmental conditions. Formed at the interface between terrestrial and aquatic environments, these biodiversity-rich ecosystems are a valuable resource that deliver a range ecosystem services (the benefits people derive from ecosystems). Sand dune ecosystem services include agricultural products, storm protection through coastal defence, river water purificat...

Wood, M. D.; Beresford, N. A.; Barnett, C. L.; Copplestone, D.

2011-01-01

277

Nanostructure of a cold drawn tempered martensitic steel  

International Nuclear Information System (INIS)

The carbon atom distribution in a tempered martensitic steel processed by cold drawing was investigated with a three-dimensional atom probe. Data clearly show that cementite starts to decompose at an early stage of deformation. This indicates that the driving force of cementite decomposition during plastic deformation is not related to a strong increase of the interfacial energy. Carbon atmospheres were also analysed. They probably result from pipe diffusion of carbon atoms along dislocations pinned by Fe3C carbides

278

Structural strength of steels with tempered martensite structure  

International Nuclear Information System (INIS)

Diagram of structural strength for structural steels, plotted in Ksub(IC)-?sub(0.2) coordinates, is presented. It is shown that steels with martensite structure possess low structural strength. Possible methods of increasing structural strength of hardened and low-tempered steels, based on change of real austenite grain composition, size and boundary configuration, are considered. Results of experiments for 40Kh and 45KhN2MFA steels are given

279

Parallel Tempering Algorithm for Conformational Studies of Biological Molecules  

CERN Document Server

The effectiveness of a new algorithm, parallel tempering, is studied for numerical simulations of biological molecules. These molecules suffer from a rough energy landscape. The resulting slowing down in numerical simulations is overcome by the new method. This is demonstrated by performing simulations with high statistics for one of the simplest peptides, Met-enkephalin. The numerical effectiveness of the new technique was found to be much better than traditional methods and is comparable to sophisticated methods like generalized ensemble techniques.

Hansmann, Uwe H E

1997-01-01

280

Efficient assignment of the temperature set for Parallel Tempering  

International Nuclear Information System (INIS)

We propose a simple algorithm able to identify a set of temperatures for a Parallel Tempering Monte Carlo simulation, that maximizes the probability that the configurations drift across all temperature values, from the coldest to the hottest ones, and vice versa. The proposed algorithm starts from data gathered from relatively short Monte Carlo simulations and is straightforward to implement. We assess its effectiveness on a test case simulation of an Edwards–Anderson spin glass on a lattice of 123 sites.

 
 
 
 
281

Increase in forest growth: new evidences from temperate forests  

Directory of Open Access Journals (Sweden)

Full Text Available A paper recently published on PNAS provides a new evidence for an increase in forest growth in temperate forests. The possible causes of this process are discussed. The results show a relation between this change in tree growth with the increase in atmospheric CO2 concentration, temperature, and length of growth season. A better understanding of the specific mechanisms involved and the assessment of the consequences on the current and future global changes are needed.

Lingua E

2010-07-01

282

Nanostructure of a cold drawn tempered martensitic steel  

CERN Document Server

The carbon atom distribution in a tempered martensitic steel processed by cold drawing was investigated with a three-dimensional atom probe. Data clearly show that cementite starts to decompose at the early stage of deformation. This indicates that the driving force of cementite decomposition during plastic deformation is not related to a strong increase of the interfacial energy. Carbon atmospheres were also analysed. They probably result from pipe diffusion of carbon atoms along dislocations pined by Fe3C carbides.

Sauvage, X; Malandain, J J; Pareige, P; Sauvage, Xavier; Quelennec, Xavier; Malandain, Jean-Jacques; Pareige, Philippe

2006-01-01

283

TEM studies of tempered structural steels with Ni  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Purpose: The reason for writing this paper was to describe the influence of Ni addition on the microstructure of structural steels after tempering. In this investigation, four model alloys of the variable concentration of Ni and constant concentration of carbon and other elements were used.Design/methodology/approach: The alloys were melted in air and hot forged into bars 20×35 mm. The samples for investigations were machined after normalizing. All samples for TEM investigations were used in...

Pacyna, J.; Ba?a, P.; Krawczyk, J.

2007-01-01

284

Groundwater flow modelling of periods with temperate climate conditions - Laxemar  

Energy Technology Data Exchange (ETDEWEB)

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

Joyce, Steven; Simpson, Trevor; Hartley, Lee; Applegate, David; Hoek, Jaap; Jackson, Peter; Roberts, David; Swan, David (Serco Technical Consulting Services (United Kingdom)); Gylling, Bjoern; Marsic, Niko (Kemakta Konsult AB, Stockholm (Sweden)); Rhen, Ingvar (SWECO Environment AB, Falun (Sweden))

2010-12-15

285

Groundwater flow modelling of periods with temperate climate conditions - Laxemar  

International Nuclear Information System (INIS)

As a part of the license application for a final repository for spent nuclear fuel at Forsmark, the Swedish Nuclear Fuel and Waste Management Company (SKB) has undertaken a series of groundwater flow modelling studies. These represent time periods with different hydraulic conditions and the simulations carried out contribute to the overall evaluation of the repository design and long-term radiological safety. This report concerns the modelling of a repository at the Laxemar-Simpevarp site during temperate climate conditions as a comparison to corresponding modelling carried out for Forsmark /Joyce et al. 2010/. The collation and implementation of onsite hydrogeological and hydrogeochemical data from previous reports are used in the construction of a Hydrogeological base case (reference case conceptualisation) and then an examination of various areas of uncertainty within the current understanding by a series of model variants. The Hydrogeological base case models at three different scales, 'repository', 'site' and 'regional' make use of a discrete fracture network (DFN) and equivalent continuous porous medium (ECPM) models. The use of hydrogeological models allow for the investigation of the groundwater flow from a deep disposal facility to the biosphere and for the calculation of performance measures that will provide an input to the site performance assessment. The focus of the study described in this report has been to perform numerical simulations of the hydrogeological system from post-closure and throughout the temperate period up until the receding shoreline leaves the modelling domain at around 15,000 AD. Besides providing quantitative results for the immediate temperate period following post-closure, these results are also intended to give a qualitative indication of the evolution of the groundwater system during future temperate periods within an ongoing cycle of glacial/inter-glacial events

286

Environmental Controls and Management Effects on Ecosystem Carbon Exchange in Two Grazed Temperate Grasslands  

Science.gov (United States)

Temperate grasslands constitute over 30% of the Earth's naturally-occurring biomes and make an important contribution towards the partial mitigation of anthropogenic greenhouse gas emissions by terrestrial ecosystems. Accumulation of carbon (C) in grassland systems predominantly takes place in below-ground repositories, enhanced by the presence of a stable soil environment with low carbon turnover rates, active rhizodeposition and high levels of residue and organic inputs. However, this C sequestration is strongly influenced by soil characteristics and climatic variables. Furthermore, in managed pasture systems, carbon exchange across the soil-atmosphere boundary is additionally affected by management activities, such as biomass removal, grazing events and the deposition or application of organic amendments. These biotic and abiotic factors contribute greatly towards the large uncertainty associated with the carbon balance of grassland ecosystems and demand further analysis. In the present study, the controls and drivers of carbon dynamics in two rotationally-grazed grasslands in Ireland were examined. The sites experience similar temperate climatic regimes but differ in soil texture classification and stocking rate. Eddy covariance measurements of net ecosystem exchange of carbon were complemented by regular assessment of standing biomass, leaf cover, harvest exports and organic amendment inputs. Our study showed that mild weather conditions and an extended growing season sustained net C accumulation at both sites for at least ten months of the year. Despite differing soil drainage characteristics, winter fluxes of net carbon exchange and its component fluxes, gross photosynthesis and ecosystem respiration, were highly comparable between the two sites. Management practices during the active growing season exerted a strong influence on both the direction and the rate of C exchange in the grassland systems, with a strong dependence, however, on the timing and intensity of the management effect. Harvest-induced reductions in productivity and net C uptake were generally greater than grazing-induced shifts, however the effects were at times mediated by environmental conditions. Our research highlighted the complex nature of the investigated grasslands resulting from the heterogeneous footprint induced by rotational grazing, grass harvesting and intensive management practices. Further work will focus on the applicability of different gap-filling methodologies for capturing the temporal and spatial variability observed. The potential of vegetation indices as a means of tracking sward development will also be investigated, with the aim of improving our understanding of the impact of vegetation dynamics on measured ecosystem carbon fluxes.

Ni Choncubhair, O.; Humphreys, J.; Lanigan, G.

2013-12-01

287

Nuclear Winter: Scientists in the Political Arena  

Science.gov (United States)

The nuclear winter phenomenon is used to illustrate the many paths by which scientific advice reaches decision makers in the United States government. Because the Reagan administration was hostile to the strategic policy that the scientific discovery seemed to demand, the leading proponent of nuclear winter, Carl Sagan, used his formidable talent for popularization to reach a larger audience.

Badash, Lawrence

2001-03-01

288

Miocene drowning of temperate (Foramol) carbonate platform: upper Miami Terrace  

Energy Technology Data Exchange (ETDEWEB)

Oligocene neritic rocks dredged from 350 m on the upper Miami Terrace exhibit repeated phosphatization as well as a filled void system containing post-Burdigalian foraminifera. During drowning, a neritic hardground was subjected to both pelagic deposition (infills) and repeated marine exposure (borings, P-coatings, etc). The neritic grainstone-packstone contains large benthic foraminifera, red algae, bryozoans, pelecypods, ahermatypic corals, echinoids, and some planktonic foraminifera. This composition association is the Foramol type characteristic of temperate to subtropical neritic environments such as the present Mediterranean, Brazilian, and New Zealand shelves. These temperate sediments derive from the local biocoenose, and accumulate slowly in deep sheets of loose skeletal debris. They become relict seaward where they are often bored, corroded, stained, glauconitized, and cemented into hardgrounds. Locally, hemipelagic cover might produce a palimpsest sequence. Recent Foramol-type platforms are undergoing drowning. The Miami Terrace is compared to very similar Miocene Foramol-type platforms now exposed in the southern Apennines. Both are characterized by neritic sequences passing upward into hemipelagics, via a palimpsest interval marked by glauconitic, phosphatic, iron-stained grains often mineralized into hardgrounds. The drowning of the Miami Terrace hence coincided with and, the authors suppose, was a result of the shift from a rapid, oligotrophic, tropical accumulation to a slow, temperate, eutrophic carbonate accumulation caused in turn by a temporary paleo-oceanographic shift to cooler, richer, neritic conditions within the history of this now subtropical setting.

Carannante, G.; Simone, L.; Neumann, C.

1986-05-01

289

INDUCTION OF TEMPERATE CYANOPHAGES USING HEAVY METAL - COPPER  

Directory of Open Access Journals (Sweden)

Full Text Available Presence of prophages in cells of three isolates of Anabaena sp. (Anabaena sp.1, sp.2 and sp.3, Anabaena cylindrica, Nostoc muscorum and Oscillatoria sp. was investigated. Copper sulfate at concentration of 3.1x10-4 M was successfully used for induction of temperate cyanophages. Among the cyanobacterial isolates tested Anabaena cylindrica was found to contain a prophage. A temperate phage was induced from Anabaena cylindrica by copper sulfate treatment and designated Ac-1. The induced phage isolate formed hazy circular plaques of 5 mm in diameter. The thermal inactivation point and longevity in vitro of the induced phage isolate (Ac-1 were found to be 70°C and 36 hrs., respectively. The induced cyanophage particles were examined by transmission electron microscopy. The phage particles were of head and tail type. The head diameter, tail length and tail width were found to be 50 nm, 116.6 nm and 8.3 nm, respectively.Ultrathin sections of infected A. cylindrica cells with temperate cyanophage and healthy ones were examined by electron microscopy. Marked changes in protoplasm and cell membrane, i.e. coagulation of protoplasm, formation of vesicles and vacuoles were observed in the infected cells as compared to the healthy ones. Phage particles were detected inside the infected A. cylindrica cells. Moreover, lysis of cell wall and release of the induced phage particles were also observed.

MAREI E.M.

2013-09-01

290

The possibility of tribopair lifetime extending by welding of quenched and tempered stainless steel with quenched and tempered carbon steel  

Directory of Open Access Journals (Sweden)

Full Text Available In the conditions of tribocorrosion wear, extending of parts lifetime could be achieved by using stainless steel,which is hardened to sufficiently high hardness. In the tribosystem bolt/ bushing shell/link plate of the bucket elevator transporter conveyor machine, the previously quenched and tempered martensitic stainless steel for bolts is hardened at ?47 HRC and welded with the quenched and tempered high yield carbon steel for bolts. Additional material, based on Cr-Ni-Mo (18/8/6 is used. The microstructure and hardness of welded samples are tested. On the tensile tester, resistance of the welded joint is tested with a simulated experiment. Dimensional control of worn tribosystem elements was performed after six months of service.

V. Maruši?

2015-04-01

291

Spent nuclear fuel project cold vacuum drying facility tempered water and tempered water cooling system design description  

Energy Technology Data Exchange (ETDEWEB)

This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Tempered Water (TW) and Tempered Water Cooling (TWC) System . The SDD was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), The HNF-SD-SNF-DRD-O02, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the TW and TWC equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SOD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved.

IRWIN, J.J.

1998-11-30

292

Spent nuclear fuel project cold vacuum drying facility tempered water and tempered water cooling system design description  

International Nuclear Information System (INIS)

This document provides the System Design Description (SDD) for the Cold Vacuum Drying Facility (CVDF) Tempered Water (TW) and Tempered Water Cooling (TWC) System . The SDD was developed in conjunction with HNF-SD-SNF-SAR-002, Safety Analysis Report for the Cold Vacuum Drying Facility, Phase 2, Supporting Installation of Processing Systems (Garvin 1998), The HNF-SD-SNF-DRD-O02, 1998, Cold Vacuum Drying Facility Design Requirements, and the CVDF Design Summary Report. The SDD contains general descriptions of the TW and TWC equipment, the system functions, requirements and interfaces. The SDD provides references for design and fabrication details, operation sequences and maintenance. This SOD has been developed for the SNFP Operations Organization and shall be updated, expanded, and revised in accordance with future design, construction and startup phases of the CVDF until the CVDF final ORR is approved

293

Prediction of hardness in pieces of quenched and tempered steel  

International Nuclear Information System (INIS)

This presentation describes the first stage of a work plan to obtain a simple software, for predicting properties at certain points of a quenched and tempered piece. In this first stage, this prediction is limited to cylindrical pieces made with steels whose chemical composition is within a certain range. The methodology basically consists of obtaining , from experimental data, a mathematical tool able to predict the hardness value, for Jominy test piece ends made with this type of steel. This meant beginning with the analysis of the usual forms of theoretical calculation of Jominy curves of quenched samples, which resulted in a proposal to modify the Just equation. Two different mathematical methods were then developed, that could predict hardness values in tempered Jominy test pieces. One, based on the determination of polynomic equations, that reproduces the loss of hardness at points along the test piece, base on the quenching value and as a function of the tempering temperature. The other one, which uses the lineal multidimensional interpolation method, because of its ease of application, has been selected as the mathematical tool to use in the software under development. At this stage of the work, the relationship between the points on the piece and those on the Jominy test pieces is carried out by the Lamont method and the representative variable of the temperature/time combination for the tempering process itself, is obtained with software based on the Hollomon and Jaffe expression. Data is needed to define: a) chemical composition and grain size of the steel used, b) diameter of the piece, c) 'HG' severity of the quenching medium d) temperature and time of the tempering. The work's second stage continued with the addition of hardness values measured in Jominy test pieces made with other steels. The chemical composition and grain size data of each steel introduced are converted by the software into one more variable, using the concept of ideal critical diameter. The result from the computer process should be the 'U curve of hardnesses', based on the prediction of the hardness value that the material will have, at points along the radius of a circular piece. So the engineer now has an easy, quick design tool with acceptable margins of error. When selecting the steel to use in producing the mechanical piece, he/she can make a better comparison of the possible offers of treated material, with respect to the data provided by the calculation of requests (CW)

294

Properties of heat affected zones in repair welds of pressure vessel steels  

International Nuclear Information System (INIS)

This study has revealed that the trempering of the HAZ of a repair weld will remain inadequate both with the half-bead and temper-bead technique. In the case of the half-bead-technique, the temperature penetration is too extensive causing reaustenitization of the HAZ and almost no tempering. The temper-bead method seems on the average to be better but due to the fluctuation and the narrow benefical temperature range the HAZ will not be completely tempered. The results of weld thermal simulations have shown that the ductility of the HAZ can be properly restored only when due to the second weld layer the peak temperature in the HAZ falls between 5700C and 7200C. The depth of this temperature zone is less than 2 mm and thus too small for the perfect realization of the ideas of the half-bead or temper-bead methods. However, the impact ductility of the HAZ is fairly good for both methods because the the HAZ contains frequent tough obstacles which prevent the cracks to run along the HAZ. (orig.)

295

Northward migrating trees establish in treefall gaps at the northern limit of the temperate-boreal ecotone, Ontario, Canada.  

Science.gov (United States)

Climate change is expected to promote migration of species. In ecotones, areas of ecological tension, disturbances may provide opportunities for some migrating species to establish in otherwise competitive environments. The size of and time since disturbance may determine the establishment ability of these species. We investigated gap dynamics of an old-growth red pine (Pinus resinosa Sol. ex Aiton) forest in the Great Lakes-St. Lawrence forest in northern Ontario, Canada, a transition zone between temperate and boreal forest. We investigated the effects of gaps of different sizes and ages on tree species abundance and basal area. Our results show that tree species from the temperate forest further south, such as red maple (Acer rubrum L.), red oak (Quercus rubra L.), and white pine (Pinus strobus L.), establish more often in large, old gaps; however, tree species that have more northern distributions, such as black spruce (Picea mariana Mill.), paper birch (Betula papyrifera Marsh.), and red pine show no difference in establishment ability with gap size or age. These differences in composition could not be attributed to autogenic succession. We conclude that treefall gaps in this forest facilitate the establishment of northward migrating species, potentially providing a pathway for future forest migration in response to recent changes in climate. PMID:20859751

Leithead, Mark D; Anand, Madhur; Silva, Lucas C R

2010-12-01

296

Dilatometric and hardness analysis of C45 steel tempering with different heating-up rates  

Directory of Open Access Journals (Sweden)

Full Text Available Modelling of technological processes of heat treatment or welding, involving multiple heat source transitions, requires considering the phenomenon of tempering. In work have been presented results of dilatometric research of hardened C45 steel subjected to tempering. The analysis of the influence of heating rate at the kinetic determined from dilatometric curves has been made. There have also been estimated quantities of transformation expansions and thermal expansion coefficients of hardening and tempering structures (austenite, ferrite, pearlite, martensite and sorbite. The analysis of tempering time influence on the hardness of tempered steel has been made. Functions associating hardness with tempering time (rate of heating-up in technological processes based on short-timed action of a heat source (eg. laser treatment have been suggested.

A. Kulawik

2012-01-01

297

The tropicalization of temperate marine ecosystems: climate-mediated changes in herbivory and community phase shifts.  

Science.gov (United States)

Climate-driven changes in biotic interactions can profoundly alter ecological communities, particularly when they impact foundation species. In marine systems, changes in herbivory and the consequent loss of dominant habitat forming species can result in dramatic community phase shifts, such as from coral to macroalgal dominance when tropical fish herbivory decreases, and from algal forests to 'barrens' when temperate urchin grazing increases. Here, we propose a novel phase-shift away from macroalgal dominance caused by tropical herbivores extending their range into temperate regions. We argue that this phase shift is facilitated by poleward-flowing boundary currents that are creating ocean warming hotspots around the globe, enabling the range expansion of tropical species and increasing their grazing rates in temperate areas. Overgrazing of temperate macroalgae by tropical herbivorous fishes has already occurred in Japan and the Mediterranean. Emerging evidence suggests similar phenomena are occurring in other temperate regions, with increasing occurrence of tropical fishes on temperate reefs. PMID:25009065

Vergés, Adriana; Steinberg, Peter D; Hay, Mark E; Poore, Alistair G B; Campbell, Alexandra H; Ballesteros, Enric; Heck, Kenneth L; Booth, David J; Coleman, Melinda A; Feary, David A; Figueira, Will; Langlois, Tim; Marzinelli, Ezequiel M; Mizerek, Toni; Mumby, Peter J; Nakamura, Yohei; Roughan, Moninya; van Sebille, Erik; Gupta, Alex Sen; Smale, Dan A; Tomas, Fiona; Wernberg, Thomas; Wilson, Shaun K

2014-08-22

298

Anatomical structure of the annual shoots axis of introduced Pterostyrax species due to their winter hardiness  

Directory of Open Access Journals (Sweden)

Full Text Available The similarity of the anatomical structure of the axis of annual shoots of Pterostyrax hispida (Sieb. et Zucc. and P. c o r y m b o s a (Sieb. et Zucc. has established. One of the possible reasons for high winter hardiness of these plants in the introduction is a thick layer of cuticle, sclerenchyma on the periphery of the stem, and intense lignifications of histological elements of bark, wood and perymedulyar zone.

Y.V. Kosar

2012-03-01

299

Effect of surface HFC tempering on notch sensitivity of quenched 40KhN steel  

International Nuclear Information System (INIS)

Surface HFC tempering is studied for its effect on the notch sensitivity of 40KhN steel. Impact bending, tensile and bolt tensile-cross-threading tests are carried out for specimens with a ring-notch. It is shown that the presence of plastic surface layer produced by the HFC tempering essentially decreases notch sensitivity of hardened 40KhN steel, optimal depth of tempering depending on the notch and specimen diameter as well as on the type of loading

300

Intraspecific Variation in Leaf Life Span for the Semi-evergreen Liana Akebia trifoliata is Caused by Both Seasonal and Aseasonal Factors in a Temperate Forest  

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Full Text Available We investigated the leaf demography of a temperate woody liana, Akebia trifoliata, in a temperateforest in Japan. Akebia is semi-evergreen: some leaves are shed before winter, while others remain through thewinter. Previous studies of semi-evergreen species found that variation in leaf life span was caused by variationin the timing of leaf emergence. Leaves that appeared just before winter over-wintered, while leaves appearingearlier were shed. However, it is unclear whether leaves of the same cohort (i.e., leaves that appear at the sametime within a single site show variation in life span under the effect of strong seasonality. To separate variationin life span among the leaves in each cohort from variation among cohorts, we propose a new method - thesingle leaf diagram, which shows the emergence and death of each leaf. Using single leaf diagrams, our studyrevealed that Akebia leaves within a cohort showed substantial variation in life span, with some over-winteringand some not. In addition, leaves on small ramets in the understory showed great variation in life span, whileleaves on large ramets, which typically reach higher positions in the forest canopy, have shorter lives. As a result,small ramets were semi-evergreen, whereas large ramets were deciduous. The longer lives of leaves on smallramets can be interpreted as a shade-adaptive strategy in understory plants.

Koyama, Kohei

2008-08-01

 
 
 
 
301

Half a Century of Schladming Winter Schools  

International Nuclear Information System (INIS)

The Schladming Winter Schools have started as early as in 1962. Over the times the yearly Schools have closely followed the actual developments in nuclear, particle, or more generally, in theoretical physics. Several new achievements have first been dealt with in length in the lectures at the Schladming Winter School. It has seen very prominent lecturers, among them a series of Nobel laureates (some of them reporting on their works even before they got their Nobel prizes). I will try to highlight the role of the Schladming Winter Schools in pro- mulgating new developments of theoretical physics in depth at the lectures given over the past 50 years. (author)

302

Phase transformation and impact properties in the experimentally simulated weld heat-affected zone of a reduced activation ferritic/martensitic steel  

Science.gov (United States)

In this work, the phase transformation and impact properties in the weld heat-affected zone (HAZ) of a reduced activation ferritic/martensitic (RAFM) steel are investigated. The HAZs were experimentally simulated using a Gleeble simulator. The base steel consisted of tempered martensite through normalizing at 1000 °C and tempering at 750 °C, while the HAZs consisted of martensite, ?-ferrite and a small volume of autotempered martensite. The impact properties using a Charpy V-notch impact test revealed that the HAZs showed poor impact properties due to the formation of martensite and ?-ferrite as compared with the base steel. In addition, the impact properties of the HAZs further deteriorated with an increase in the ?-ferrite fraction caused by increasing the peak temperature. The impact properties of the HAZs could be improved through the formation of tempered martensite after post weld heat treatment (PWHT), but they remained lower than that of the base steel because the ?-ferrite remained in the tempered HAZs.

Moon, Joonoh; Lee, Chang-Hoon; Lee, Tae-Ho; Jang, Min-Ho; Park, Min-Gu; Han, Heung Nam

2014-12-01

303

Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland  

Science.gov (United States)

Land-atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits marked seasonal and inter-annual variability, which subsequently affects the carbon sink strength of catchments across multiple temporal scales. Long-term studies are needed to fully capture the natural variability and therefore identify the key hydrometeorological drivers in the net ecosystem exchange (NEE) of CO2. NEE has been measured continuously by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in central Scotland, since 2002. Hence this is one of the longest peatland NEE studies to date. For 11 yr, the site was a consistent, yet variable, atmospheric CO2 sink ranging from -5.2 to -135.9 g CO2-C m-2 yr-1 (mean of -64.1 ± 33.6 g CO2-C m-2 yr-1). Inter-annual variability in NEE was positively correlated to the length of the growing season. Mean winter air temperature explained 87% of the inter-annual variability in the sink strength of the following summer, indicating a phenological memory-effect. Plant productivity exhibited a marked hysteresis with respect to photosynthetically active radiation (PAR) over the growing season, indicative of two separate growth regimes. Ecosystem respiration (Reco) and gross primary productivity (GPP) were closely correlated (ratio 0.74), suggesting that autotrophic processes were dominant. Whilst the site was wet most of the year (water table depth <5 cm) there were indications that heterotrophic respiration was enhanced by drought, which also depressed GPP. NEE was compared to 5 other peatland sites which have published long-term NEE records. The CO2 uptake rate during the growing season was comparable to 3 other European sites, however the emission rate during the dormant season was significantly higher.

Helfter, C.; Campbell, C.; Dinsmore, K. J.; Drewer, J.; Coyle, M.; Anderson, M.; Skiba, U.; Nemitz, E.; Billett, M. F.; Sutton, M. A.

2014-10-01

304

Experimental warming does not enhance soil respiration in a semiarid temperate forest-steppe ecosystem  

DEFF Research Database (Denmark)

The influence of simulated climate change on soil respiration was studied in a field experiment on 4 m x 5 m plots in the semiarid temperate Pannonian sand forest-steppe. This ecosystem type has low productivity and soil organic matter content, and covers large areas, yet data on soil carbon fluxes are still limited. Soil respiration rate-measured monthly between April and November from 2003 to 2006-remained very low (0.09 - 1.53 mu mol CO2 m(-2) s(-1))in accordance with the moderate biological activity and low humus content of the nutrient poor, coarse sandy soil. Specific soil respiration rate ( calculated for unit soil organic matter content), however, was relatively high (0.36 - 7.92 mu mol CO g(-1) C(org)h(-1)) suggesting substrate limitation for soil biological activity. During the day, soil respiration rate was significantly lower at dawn than at midday, while seasonally clear temperature limitation in winter and water limitation in summer were detected. Between years, annual precipitation appeared to be important in determining soil carbon efflux intensity. Nocturnal warming increased soil temperature in 1 cm depth at dawn by 1.6 degrees C on the average, and decreased topsoil (0-11 cm) moisture content by 0.45 vol%. Drought treatment decreased soil moisture content by an average of 0.81 vol%. Soil respiration rate tended to decrease by 7-15% and 13-15% in response to heat and drought treatment, respectively, although the changes were not statistically significant. Nocturnal warming usually prevented dew formation, and that probably also influenced soil respiration. Based on these results, we expect a reduction in the volume and rate of organic matter turnover in this ecosystem in response to the anticipated climate change in the region.

Lellei-Kovacs, E.; Kovacs-Lang, E.

2008-01-01

305

Spring molybdenum enrichment in scallop shells: a potential tracer of diatom productivity in temperate coastal environments (Brittany, NW France)  

Science.gov (United States)

Skeletal molybdenum/calcium ([Mo]/[Ca])shell ratios were examined in shells of the Great Scallop Pecten maximus collected in temperate coastal environments of Western Europe (42 to 49° N). These ratios were determined by quantitative LA-ICP-MS analyses of daily striae taken every third day (i.e. a temporal resolution of 3 days) in 36 flat valves (2-years old; 3 shells/year). Variations of ([Mo]/[Ca])shell ratios were significant and reproducible for scallops from the same population, from different years (1998-2004) and temperate coastal locations (NW France). The [Mo]/[Ca])shell ratios exhibit typical profiles characterized by a background content, below the detection limit for this method (Brest (France) was investigated in particular because of its long term observations on scallop communities, environmental variables, and high resolution analyses of dissolved Mo in bottom seawater in 2000. In 2000, dissolved Mo exhibited a significant increase in concentration just preceding the maximum ([Mo]/[Ca])shell ratio. Both the intense monitoring survey in 2000 and over the 7-year period indicates that the ([Mo]/[Ca])shell maximum is directly influenced by spring changes of environmental conditions at the sediment water interface (SWI), occurring subsequent to the intense and periodic spring bloom. Spring maxima of ([Mo]/[Ca])shell ratios are closely correlated to the extent of silicic acid and nitrate depletion in seawater between winter and late spring (r2=0.878 and 0.780, pBrest. The Mo inputs in bottom waters and subsequent shell enrichment are thus suggested to be directly or indirectly influenced by such biogenic material input at the SWI. The [Mo]/[Ca])shell records thus reveal unexpected biogeochemical cycles of Mo influenced by coastal spring productivity, faithfully recorded in scallop shells.

Barats, A.; Amouroux, D.; Pécheyran, C.; Chauvaud, L.; Thébault, J.; Donard, O. F. X.

2010-01-01

306

Development of Roller Ends Forced-Contact Model and Cambering Technology for UCM Temper Mill (II——Development of cambering technology for UCM temper mill  

Directory of Open Access Journals (Sweden)

Full Text Available Roller ends forced-contact and overmuch roll consumption are the widespread problems in temper rolling process of thin strip for two-stand UCM temper mill. Fully thinking the equipment and technology characteristics of UCM temper mill, we took the newly-built 1220 UCM temper mill of Baosteel as the research object in this paper. A model of roller ends forced-contact and a calculation model of flatness for UCM temper mill are established after a great deal of site tracing and theoretical researches. On this basis, an optimal mathematical model of roll shape which is suited for UCM temper mill is developed. Working roll curve is the combination of cosine curve and high order curve. The cosine subentry is used to control edge wave, the high order curve subentry is used to control roller ends forced-contact. Furthermore, the chamfering curve of middle roller end is optimized. Those are the innovations. Through the above-mentioned technology, pressure distribution between rollers caused by the shift of middle roll becomes more homogeneous, pressure peak disappeared, working life of roll is improved effectively as well. Relevant technologies have been used to the practice of 1220 UCM temper mill of Baosteel and have achieved good use effects, which is of further extending application value.

Zhenhua Bai

2011-07-01

307

Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya  

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Full Text Available Abstract Background The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC. However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known. Results This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora and subtropical (Pinus roxburghii forests, respectively. Conclusion The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation

Kumar Munesh

2009-08-01

308

Bead temperature effects on FCAW heat-affected zone hardness  

Energy Technology Data Exchange (ETDEWEB)

Hardness limits for welding procedure qualification are often imposed to lessen the chances of delayed hydrogen cracking during production fabrication. Temper bead techniques have been used by fabricators during these qualifications to improve their chances of success. This practice involves using the heat of additional weld beads to soften the heat-affected zone (HAZ) hardness in the base metal next to the weld where the hardness is the greatest. The technique works under controlled conditions, but the consistency for field use was questionable. This report describes an investigate of the effect of welding parameters, base metal chemical composition, and weld bead placement on HAZ softening. An empirical formula developed from base plate chemical composition, weld cooling time, and temper bead placement can be used to estimate the amount of HAZ tempering. Combined with an appropriate hardness prediction formula, it can help find the welding procedure needed to achieve a desired maximum HAZ hardness, or predict the HAZ hardness of existing welds. Based on the results of the study, bead temperature is not recommended for HAZ hardness control on large scale fabrications.

Kiefer, J.H. [Conoco, Inc., Houston, TX (United States)

1995-11-01

309

Winter emissions of carbon dioxide, methane and nitrous oxide from a minerotrophic fen under nature conservation management in north-east Germany  

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Full Text Available Drained peatlands are known to be important sources of carbon dioxide (CO2 and nitrous oxide (N2O. While CO2 emissions occur mainly during the growing season, large N2O emissions may occur during the non-growing season as well. Peatland re-wetting may be an effective measure to prevent those emissions. However, recent research shows that re-wetted peatlands may release large amounts of methane (CH4 during the years immediately after re-wetting whereas abandonment of intensive grassland on drained peat soils possibly leads to low nutrient supply and thus to small greenhouse gas (GHG emissions. Here we examine the role of extensification practices (such as abandonment of mineral fertilisation, reduced cutting frequency and a cattle-free winter period on GHG emissions from a temperate peatland during winter. From November 2009 to March 2010 GHG measurements were made on a minerotrophic fen five years after intensive grassland use was abandoned. During the measurement period CO2 and N2O emissions amounted to 4.4 t ha-1 and 2.6 t ha-1 CO2-equivalent, whilst CH4 emissions were negligible. Altogether the site emitted 7 t ha-1 CO2-equivalent, of which 37 % was N2O, even though the winter 2009/2010 was extraordinarily cold. Thus, extensification of grassland use alone may not be sufficient to reduce GHG emissions from temperate peatlands.

V. Huth

2012-04-01

310

Apparent climatically induced increase of tree mortality rates in a temperate forest  

Science.gov (United States)

We provide a first detailed analysis of long-term, annual-resolution demographic trends in a temperate forest. After tracking the fates of 21 338 trees in a network of old-growth forest plots in the Sierra Nevada of California, we found that mortality rate, but not the recruitment rate, increased significantly over the 22 years of measurement (1983-2004). Mortality rates increased in both of two dominant taxonomic groups (Abies and Pinus) and in different forest types (different elevational zones). The increase in overall mortality rate resulted from an increase in tree deaths attributed to stress and biotic causes, and coincided with a temperature-driven increase in an index of drought. Our findings suggest that these forests (and by implication, other water-limited forests) may be sensitive to temperature-driven drought stress, and may be poised for die-back if future climates continue to feature rising temperatures without compensating increases in precipitation. ?? 2007 Blackwell Publishing Ltd/CNRS.

van Mantgem, P.J.; Stephenson, N.L.

2007-01-01

311

Effects of wave exposure on circulation in a temperate reef environment  

Science.gov (United States)

Observations of waves and currents in a temperate reef environment off southwestern Western Australia over a period of 1 year reveal the relative importance of wind and wave forcing. During periods of low waves, linear regression analysis shows alongshore currents seaward and shoreward of the reef line are reasonably well predicted using 1% and 0.5% of the wind speed, respectively. However, shoreward of the reef line anomalously strong currents were often observed during periods of light or even opposing winds and the mean sea surface was elevated relative to offshore of the reefs. These anomalous currents and elevated sea level occur during periods of high waves and both are correlated with the root-mean-square wave height seaward of the reefs, similar to what has been observed in coral reef environments. The observations were simulated with the numerical model XBeach which includes radiation stress forcing due to the presence of the waves. The model was also used to examine the dynamics of the wave-driven flow in terms of the momentum balance. As on a coral reef, through the surf zone over the reef bottom, friction is balanced by the sum of the radiation stress gradient and pressure gradient. Away from the reefs the radiation stress gradients are small and the momentum balance is between bottom friction and pressure gradient.

Symonds, Graham; Zhong, Liejun; Mortimer, Nick A.

2011-09-01

312

Hydrogen induced cold cracking studies on armour grade high strength, quenched and tempered steel weldments  

Energy Technology Data Exchange (ETDEWEB)

Quenched and tempered (Q and T) steels are prone to hydrogen induced cracking (HIC) in the heat affected zone after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy because of higher solubility for hydrogen in austenitic phase. The use of stainless steel consumables for a non-stainless steel base metal is not economical. Hence, alternate consumables for welding Q and T steels and their vulnerability to HIC need to be explored. Recent studies proved that low hydrogen ferritic (LHF) steel consumables can be used to weld Q and T steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the influence of welding consumables and welding processes on hydrogen induced cold cracking of armour grade Q and T steel welds by implant testing. Shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes were used for making welds using ASS and LHF welding consumables. ASS welds made using FCAW process offered a higher resistance to HIC than all other welds considered in this investigation. (author)

Magudeeswaran, G.; Balasubramanian, V. [Centre for Materials Joining Research (CEMAJOR), Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar 608 002, Tamil Nadu (India); Madhusudhan Reddy, G. [Metal Joining Section, Defence Metallurgical Research Laboratory (DMRL), Kanchanbagh (P.O.) Hyderabad 560 058 Andhra Pradesh (India)

2008-04-15

313

Simulating the carbon balance of a temperate larch forest under various meteorological conditions  

Directory of Open Access Journals (Sweden)

Full Text Available Abstract Background Changes in the timing of phenological events may cause the annual carbon budget of deciduous forests to change. Therefore, one should take such events into account when evaluating the effects of global warming on deciduous forests. In this article, we report on the results of numerical experiments done with a model that includes a phenological module simulating the timing of bud burst and other phenological events and estimating maximum leaf area index. Results This study suggests that the negative effects of warming on tree productivity (net primary production outweigh the positive effects of a prolonged growing season. An increase in air temperature by 3°C (5°C reduces cumulative net primary production by 21.3% (34.2%. Similarly, cumulative net ecosystem production (the difference between cumulative net primary production and heterotrophic respiration decreases by 43.5% (64.5% when temperatures are increased by 3°C (5°C. However, the positive effects of CO2 enrichment (2 × CO2 outweigh the negative effects of warming ( Conclusion Although the model was calibrated and validated for a specific forest ecosystem, the implications of the study may be extrapolated to deciduous forests in cool-temperate zones. These forests share common features, and it can be conjectured that carbon stocks would increase in such forests in the face of doubled CO2 and increased temperatures as long as the increase in temperature does not exceed 5°C.

Watanabe Tsutomu

2007-05-01

314

Pure stands of temperate forest tree species modify soil respiration and N turnover  

Science.gov (United States)

The effects of five different tree species common in the temperate zone, i.e. beech (Fagus sylvatica L.), pedunculate oak (Quercus robur L.), Norway spruce (Picea abies [L.] Karst), Japanese larch (Larix leptolepis [Sichold and Zucc.] Gordon) and mountain pine (Pinus mugo Turra), on soil respiration, gross N mineralization and gross nitrification rates were investigated. Soils were sampled in spring and summer 2002 at a forest trial in Western Jutland, Denmark, where pure stands of the five tree species of the same age were growing on the same soil. Soil respiration, gross rates of N mineralization and nitrification were significantly higher in the organic layers than in the Ah horizons for all tree species and both sampling dates. In summer (July), the highest rates of soil respiration, gross N mineralization and gross nitrification were found in the organic layer under spruce, followed by beech > larch > oak > pine. In spring (April), these rates were also higher under spruce compared to the other tree species, but were significantly lower than in summer. For the Ah horizons no clear seasonal trend was observed for any of the processes examined. A linear relationship between soil respiration and gross N mineralization (r2=0.77), gross N mineralization and gross nitrification rates (r2=0.72), and between soil respiration and gross nitrification (r2=0.81) was found. The results obtained underline the importance of considering the effect of forest type on soil C and N transformations.

Brüggemann, N.; Rosenkranz, P.; Papen, H.; Pilegaard, K.; Butterbach-Bahl, K.

2005-04-01

315

Determining efficient temperature sets for the simulated tempering method  

Science.gov (United States)

In statistical physics, the efficiency of tempering approaches strongly depends on ingredients such as the number of replicas R, reliable determination of weight factors and the set of used temperatures, TR={T1,T2,…,TR}. For the simulated tempering (ST) in particular-useful due to its generality and conceptual simplicity-the latter aspect (closely related to the actual R) may be a key issue in problems displaying metastability and trapping in certain regions of the phase space. To determine TR’s leading to accurate thermodynamics estimates and still trying to minimize the simulation computational time, here a fixed exchange frequency scheme is considered for the ST. From the temperature of interest T1, successive T’s are chosen so that the exchange frequency between any adjacent pair Tr and Tr+1 has a same value f. By varying the f’s and analyzing the TR’s through relatively inexpensive tests (e.g., time decay towards the steady regime), an optimal situation in which the simulations visit much faster and more uniformly the relevant portions of the phase space is determined. As illustrations, the proposal is applied to three lattice models, BEG, Bell-Lavis, and Potts, in the hard case of extreme first-order phase transitions, always giving very good results, even for R=3. Also, comparisons with other protocols (constant entropy and arithmetic progression) to choose the set TR are undertaken. The fixed exchange frequency method is found to be consistently superior, specially for small R’s. Finally, distinct instances where the prescription could be helpful (in second-order transitions and for the parallel tempering approach) are briefly discussed.

Valentim, A.; da Luz, M. G. E.; Fiore, Carlos E.

2014-07-01

316

Effect of plants on methane emissions from a temperate marsh in different seasons  

Science.gov (United States)

Plants play an important role in CH4 emissions from wetlands. Vascular plants transport CH4 from the anaerobic zone to the atmosphere through their aerenchyma, thereby bypassing the aerobic zone and strongly increasing CH4 emission rates. However, most studies of the effect of plants on wetland CH4 emissions are based on observations made during the growing seasons. The effects in non-growing seasons are still unclear. In this study, we conducted a clipping experiment to investigate the effects of plants on CH4 emissions from a temperate marsh in the growing and non-growing seasons. The results show that the influence of plants on CH4 emissions from the wetland varied among different seasons. Plant-mediated CH4 accounted for 38% of the total fluxes in the plant-growing season. After the growing season, whether the plants transported CH4 from the soil to the atmosphere in situ was determined by the involved environmental conditions. In autumn, the plants did not transport CH4. This is because the CH4 diffused easily in the soil and water, rather than via the plants' organs. In the surface soil freezing period, CH4 diffusion was blocked and accumulated under the frozen surface. The highly concentrated CH4 in the pore water was compelled to enter the organs of the plants and diffused by them. The 'passive diffusion' via plants transported 84% of the total CH4 emissions during this period. Nonetheless, the plants did not transport CH4 again in the deep soil freezing season. By synthesizing our data together with previous studies, we suggested that this is because the frozen soil layer was deep enough in this period to exceed the depth horizon of the plants' roots and the CH4 in free water could not enter the plants' organs.

Sun, Xiaoxin; Song, Changchun; Guo, Yuedong; Wang, Xianwei; Yang, Guisheng; Li, Yingchen; Mao, Rong; Lu, Yongzheng

2012-12-01

317

Recent carbonate sedimentation on Balearic platform: model for temperate-climate carbonate shelves  

Energy Technology Data Exchange (ETDEWEB)

Existing models for carbonate sedimentation on continental platforms are derived from the study of modern carbonate platforms in tropical climates. The Balearic platform in the western Mediterranean provides a new model for carbonate sedimentation in a temperature, semiarid climate. On most of the continental shelf around the Balearic Islands, modern sediments are exclusively bioclastic carbonates. Shoreline carbonate sediments are bioclastic sands and muds accumulating in beach-dune systems without significant tidal influence (there are no astronomical tides in the western Mediterranean ). From the upper shoreface to 35 m deep, the sandy bottom is extensively colonized by sea grass (Posidonia oceanica), the rhizomes and roots of which form a rigid entrapment that retains the sediment derived from calcareous organisms living within the sea grass and from calcareous epiphytes living on the stems and leaves. Archeological dating establishes a rate of vertical accretion in this zone of 10/sup 3/ Bubnoff units (1 Bubnoff unit = 1 mm/1000 years). Between depths of 40 and 60 m, carbonate sands are composed predominantly or red-algal fragments. Intensely bioturbated wave ripples occur in environments dominated by laminar red algae (Lithothamnium and Phymatolithon). Below depths of 60 m, coarse sediment produced by rhodolitic and ramose red algae is deposited in areas of tens to hundreds of meters in size. Biogenic buildups up to 2 m high occur in sandy areas as well as in deeper muddy areas. At the same depth in open-platform zones, the bottom topography is characterized by large hummocks several hundred meters across. From the horizontal distribution of facies, it is possible to construct the probable vertical sequence of lithofacies which would characterize carbonates accumulating on a temperate-climate carbonate shelf. Many of these lithofacies are recognized in upper Miocene limestones on the Balearic Islands.

Fornos, J.; Rodriguez-Perea, A.; Massuti, C.; Pomar, L.; Acosta, J.; Herranz, P.; Sanz, J.L.

1989-03-01

318

Bacterial and Phytoplankton Dynamics along a Trophic Gradient in a Shallow Temperate Estuary  

Science.gov (United States)

Heterotrophic bacterial and phytoplankton biomass, production, specific growth rates and growth efficiencies were studied from June to October in 1996 and from February to May in 1997 along the longitudinal axis of the Urdaibai Estuary, a shallow temperate tidal estuary. Both phytoplankton and bacterial biomass showed a distinct lower to upper estuary increasing gradient. Longitudinal variations of phytoplankton biomass were controlled mainly by inorganic nutrient availability and tidal flushing. Longitudinal variations of bacterial biomass were further influenced by allochthonous inputs of organic carbon from a wastewater treatment plant located at the upper estuary. On a temporal scale, the dilution and washout effect of river discharge was a major controlling factor of both bacterial and phytoplankton biomass in the upper estuary. In this zone there were no indications that bacteria were resource limited, and temperature was the variable that explained most of the variability in bacterial specific growth rates. In the lower estuary, however, data suggested bacteria were nitrogen limited. Likewise, phytoplankton growth rates also showed a positive correlation with inorganic nutrients in this area. Free-living bacteria were generally more abundant than attached ones all along the estuary. However, following the longitudinal gradient of turbidity, the proportion of attached bacteria increased from the lower to the upper estuary. Rates of thymidine incorporation per cell were generally higher for particle-attached bacteria than for free-living bacteria. On average, bacteria contributed only 23% of the phytoplankton plus bacterial carbon biomass. Bacterial contribution to total (bacterial plus phytoplankton) net production of organic carbon was on average 17% for surface samples and 39% for bottom samples. Average phytoplankton growth efficiency in the euphotic zone was estimated to be higher (85%) than bacterial growth efficiency (46%).

Revilla, M.; Iriarte, A.; Madariaga, I.; Orive, E.

2000-03-01

319

Transport in the spatially tempered, fractional Fokker-Planck equation  

Energy Technology Data Exchange (ETDEWEB)

A study of truncated Levy flights in super-diffusive transport in the presence of an external potential is presented. The study is based on the spatially tempered, fractional Fokker-Planck (TFFP) equation in which the fractional diffusion operator is replaced by a tempered fractional diffusion (TFD) operator. We focus on harmonic (quadratic) potentials and periodic potentials with broken spatial symmetry. The main objective is to study the dependence of the steady-state probability density function (PDF), and the current (in the case of periodic potentials) on the level of tempering, lambda, and on the order of the fractional derivative in space, alpha. An expansion of the TFD operator for large lambda is presented, and the corresponding equation for the coarse grained PDF is obtained. The steady-state PDF solution of the TFFP equation for a harmonic potential is computed numerically. In the limit lambda -> infinity, the PDF approaches the expected Boltzmann distribution. However, nontrivial departures from this distribution are observed for finite (lambda > 0) truncations, and alpha not equal 2. In the study of periodic potentials, we use two complementary numerical methods: a finite-difference scheme based on the Grunwald-Letnikov discretization of the truncated fractional derivatives and a Fourier-based spectral method. In the limit lambda -> infinity, the PDFs converges to the Boltzmann distribution and the current vanishes. However, for alpha not equal 2, the PDF deviates from the Boltzmann distribution and a finite non-equilibrium ratchet current appears for any lambda > 0. The current is observed to converge exponentially in time to the steady-state value. The steady-state current exhibits algebraical decay with lambda, as J similar to lambda(-zeta), for alpha >= 1.75. However, for alpha <= 1.5, the steady-state current decays exponentially with lambda, as J similar to e(-xi lambda). In the presence of an asymmetry in the TFD operator, the tempering can lead to a current reversal. A detailed numerical study is presented on the dependence of the current on lambda and the physical parameters of the system.

Kullberg, A. [University of California, Los Angeles; Del-Castillo-Negrete, Diego B [ORNL

2012-01-01

320

Laser beam welding tempered 300M ultrahigh mechanical strength steel  

Digital Repository Infrastructure Vision for European Research (DRIVER)

AISI 300M ultrahigh strength steel has been used in a number of high demanding applications, such as the VLS Brazilian rocket project. This work intends to propose laser beam welding, with subsequent tempering, as a possible route for the fabrication of engineering pieces of this steel. A 2 kW fiber laser was used to produce welded coupons for metallographic, hardness and tensile strength tests. It has been shown that convenient laser parameters for a 3 mm thick plate are 50 mm/s welding spee...

Sheila Medeiros de Carvalho; Milton Sérgio Fernandes de Lima

2012-01-01

 
 
 
 
321

The Research and Application of Webpage Temper-proofing System  

Directory of Open Access Journals (Sweden)

Full Text Available With the sharp increase of hacking attacks over the last couple of years, web application security has become a key concern. The attack to websites, especially the explosion of webpage interpolating incidents has becomeone of the most serious problems of it. In this paper, the system adopts Web server core embedded technology to imbed tamper detection module and application protection module into the Web server, define correspondingstrategies for temper-proofing, and realize the real-time monitoring and protection of web pages and the dynamic content in databases.

Wang Yongquan

2012-06-01

322

Joints in Tempered Glass Using Glass Dowel Discs  

DEFF Research Database (Denmark)

One of the major reasons for using glass in structures is its transparency; however, traditional mechanical joints such as friction joints and steel dowel pinned connections are compromising the transparency. The present paper describes a novel joint which is practically maintaining the complete transparency of the glass. This is achieved by using a dowel disc made entirely of tempered glass. The concept of the joint is proved by pilot tests and numerical models. From the work it is seen that the load-carrying capacity of such a connection is similar to what is found for traditionally in-plane loaded steel dowel pinned joints.

Nielsen, Jens Henrik; Poulsen, Peter Noe

323

Tempering chamber for preparation of atomically pure surfaces  

International Nuclear Information System (INIS)

The chamber consists of two telescopically arranged tubes. The fixed tube is provided with a piezoelectric resonator for evaporated particle display. A thermocouple is flexibly attached to the movable tube which, when the tube is slipped on a rotary manipulator with the sample, is in flexible contact with the sample surface. The movable tube is supported with an arm operated through a rotary bushing in the wall of the vacuum chamber recipient. The axes of analysis systems (coaxial Auger analyzer, LEED optics) and the tempering chamber axis lie in the plane of the sample to be studied. (H.S.)

324

ROV Survey of Winter Quarters Bay  

Science.gov (United States)

Title : ROV Survey of Winter Quarters Bay Type : Antarctic EAM NSF Org: OD / OPP Date : January 24 ... ice pier; (2) the ROV can go deeper than a person in SCUBA gear; (3) the ROV with a mapping device ...

325

Effects of Pre-tempering on Intercritical Annealing in Fe-2Mn-0.3C Alloy  

Science.gov (United States)

As-quenched martensite was pre-tempered at 623 K and 923 K (350 °C and 650 °C), and then it reverted to austenite by intercritical annealing at 998 K (725 °C) in a Fe-2Mn-0.3C alloy. Pre-tempering at 623 K (350 °C) accelerates austenite formation, while pre-tempering at 923 K (650 °C) significantly retards it. It is proposed that austenite nucleation is accelerated by increasing the number density and particle size of cementite during tempering, whereas austenite growth is retarded by Mn enrichment in cementite during tempering at high temperature, leading to opposite effects of pre-tempering on reversion kinetics.

Liu, Zhen-Qing; Miyamoto, Goro; Yang, Zhi-Gang; Zhang, Chi; Furuhara, Tadashi

2014-11-01

326

Nitrogen dynamics in crop sequences with winter oilseed rape and winter wheat  

Digital Repository Infrastructure Vision for European Research (DRIVER)

With the aim of improving fertiliser nitrogen (N) strategies and reducing N leaching, seasonal changes in soil N supply in crop sequences with winter wheat after winter oilseed rape were examined through field experiments. Break crop effects on wheat after oilseed rape, compared with after peas and oats, were determined as regards residual N, yield and optimum N rate (Opt-N). The impact of residues of the previous crops on net N mineralisation-immobilisation during autumn and winter was studi...

Engstro?m, Lena

2010-01-01

327

Marginal Zone Lymphoma  

Science.gov (United States)

... marginal zone lymphoma: Extranodal marginal zone lymphoma or mucosa-associated lymphoid tissue (MALT) is the most common ... Fludarabine (Fludara) • Radiation (low-dose) • Rituximab (Rituxan) • Surgical excision Treatment Options for Non-gastric MALT Non-gastric ...

328

Mosquito Species Associated Within Some Western Himalayas Phytogeographic Zones in the Garhwal Region of India  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Thirty four species of mosquitoes (Diptera: Culicidae) were collected across three phytogeographic zones; tropical (300 to 1000 m), sub tropical (1000 to 2000 m) and temperate (2000 to 3000 m) in the Garhwal region of India. They included 5 genera: Aedes, Anopheles, Armigeres, Culex and Uranotaenia. Of these, the immature forms of 23 species were recovered from different breeding habitats. The larval habitats were seepage pools, river beds, rice fields, tanks, forest pools, ditches, streams, ...

Pemola Devi, N.; Jauhari, R. K.

2007-01-01

329

Thermodynamic Properties of Polypeptide Chains. Parallel Tempering Monte Carlo Simulations  

International Nuclear Information System (INIS)

A coarse-grained model of polypeptide chains was designed and studied. The chains consisted of united atoms located at the position of alpha carbons and the coordinates of these atoms were restricted to a [310] type lattice. Two kinds of amino acids residues were defined: hydrophilic and hydrophobic ones. The sequence of the residues was assumed to be characteristic for ?-helical proteins (the helical septet). The force field used consisted of the long-range contact potential between residues and the local potential preferring conformational states, which were characteristic for ?-helices. In order to study the thermodynamics of our model we employed the Multi-histogram method combined with the Parallel Tempering (the Replica Exchange) Monte Carlo sampling scheme. The optimal set of temperatures for the Parallel Tempering simulations was found by an iterative procedure. The influence of the temperature and the force field on the properties of coil-to-globule transition was studied. It was shown that this method can give more precise results when compared to Metropolis and Replica Exchange methods. (author)

330

Nitrous oxide emission reduction in temperate biochar-amended soils  

Directory of Open Access Journals (Sweden)

Full Text Available Biochar, a pyrolysis product of organic residues, is an amendment for agricultural soils to improve soil fertility, sequester CO2 and reduce greenhouse gas (GHG emissions. In highly weathered tropical soils laboratory incubations of soil-biochar mixtures revealed substantial reductions for nitrous oxide (N2O and carbon dioxide (CO2. In contrast, evidence is scarce for temperate soils. In a three-factorial laboratory incubation experiment two different temperate agricultural soils were amended with green waste and coffee grounds biochar. N2O and CO2 emissions were measured at the beginning and end of a three month incubation. The experiments were conducted under three different conditions (no additional nutrients, glucose addition, and nitrate and glucose addition representing different field conditions. We found mean N2O emission reductions of 60 % compared to soils without addition of biochar. The reduction depended on biochar type and soil type as well as on the age of the samples. CO2 emissions were slightly reduced, too. NO3 but not NH4+ concentrations were significantly reduced shortly after biochar incorporation. Despite the highly significant suppression of N2O emissions biochar effects should not be transferred one-to-one to field conditions but need to be tested accordingly.

R. Felber

2012-01-01

331

Prediction of quenched and tempered steel and cast steel properties  

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Full Text Available Purpose: The influence of processing parameters, such as pouring temperature and cooling rate during the casting, as well as application of hot working and pre-heat treatment, on strength and toughness of quenched and tempered steel was investigated.Design/methodology/approach: Strength and toughness were presented by yield strength and Charpy-V notch toughness, respectively. Experimental procedure of material properties optimization was done using the 25-2 factor experiment.Findings: It was found out that yield strength is insensitive on differences between applied manufacturing processes, but by application of hot working and with appropriate pouring temperature the Charpy-V notch toughness is increased. Also, Charpy-V notch toughness is increased by interactive effect of the appropriate cooling rate during the casting and application of hot working.Research limitations/implications: The research was focused mainly on Charpy-V notch toughness of carbon and low alloyed heat treatable steels.Practical implications: The established algorithms can be used for prediction of tensile strength, yield strength and Charpy-V notch toughness in heat treating practice.Originality/value: Original relation for prediction of quenched and tempered steel and cast steel Charpy-V notch toughness are developed.

B. Smoljan

2011-12-01

332

Environmental drivers of ectomycorrhizal communities in Europe's temperate oak forests.  

Science.gov (United States)

Ectomycorrhizal fungi are major ecological players in temperate forests, but they are rarely used in measures of forest condition because large-scale, high-resolution, standardized and replicated belowground data are scarce. We carried out an analysis of ectomycorrhizas at 22 intensively monitored long-term oak plots, across nine European countries, covering complex natural and anthropogenic environmental gradients. We found that at large scales, mycorrhizal richness and evenness declined with decreasing soil pH and root density, and with increasing atmospheric nitrogen deposition. Shifts in mycorrhizas with different functional traits were detected; mycorrhizas with structures specialized for long-distance transport related differently to most environmental variables than those without. The dominant oak-specialist Lactarius quietus, with limited soil exploration abilities, responds positively to increasing nitrogen inputs and decreasing pH. In contrast, Tricholoma, Cortinarius and Piloderma species, with medium-distance soil exploration abilities, show a consistently negative response. We also determined nitrogen critical loads for moderate (9.5-13.5 kg N/ha/year) and drastic (17 kg N/ha/year) changes in belowground mycorrhizal root communities in temperate oak forests. Overall, we generated the first baseline data for ectomycorrhizal fungi in the oak forests sampled, identified nitrogen pollution as one of their major drivers at large scales and revealed fungi that individually and/or in combination with others can be used as belowground indicators of environmental characteristics. PMID:25277863

Suz, Laura M; Barsoum, Nadia; Benham, Sue; Dietrich, Hans-Peter; Fetzer, Karl Dieter; Fischer, Richard; García, Paloma; Gehrman, Joachim; Kristöfel, Ferdinand; Manninger, Miklós; Neagu, Stefan; Nicolas, Manuel; Oldenburger, Jan; Raspe, Stephan; Sánchez, Gerardo; Schröck, Hans Werner; Schubert, Alfred; Verheyen, Kris; Verstraeten, Arne; Bidartondo, Martin I

2014-11-01

333

Gravitational tempering in colloidal epitaxy to reduce defects further  

CERN Document Server

Less-defective colloidal crystals can be used as photonic crystals. To this end, colloidal epitaxy was proposed in 1997 as a method to reduce the stacking defects in the colloidal crystals. In this method, face-centered cubic (fcc) (001) stacking is forced by a template. In fcc (001) stacking, in contract to fcc {111} stacking, the stacking sequence is unique and thus the stacking fault can be avoided. Additionally, in 1997, an effect of gravity that reduces the stacking disorder in hard-sphere (HS) colloidal crystals was found. Recently, we have proposed a gravitational tempering method based on a result of Monte Carlo (MC) simulations using the HS model; after a colloidal crystal is grown in a relatively strong gravitational field, the defects can be reduced by decreasing the gravity strength and maintain for a period of time. Here, we demonstrate this method using MC simulations with a programed gravitation. The dramatic disappearance of defect structures is observed. Gravitational tempering can complement...

Mori, Atsushi; Sato, Masahide

2014-01-01

334

Type 1,1-operators on spaces of temperate distributions  

DEFF Research Database (Denmark)

This paper is a follow-up on the author’s general definition of pseudo-differential operators of type 1,1, in Hörmander’s sense. It is shown that such operators are always defined on the smooth functions that are temperate; and moreover are defined and continuous on the space of temperate distributions, whenever they fulfil the twisted diagonal condition of Hörmander, or more generally when they belong to the self-adjoint subclass. Continuity in Lp -Sobolev spaces and Hölder–Zygmund spaces, and more generally in Besov and Lizorkin–Triebel spaces, is for positive smoothness also proved on the basis of the definition. These continuity results are extended to arbitrary real smoothness indices for operators that fulfil the twisted diagonal condition or belong to the self-adjoint subclass. With systematic Littlewood–Paley analysis the well-known paradifferential decomposition is also derived for type 1,1-operators. The proofs are based on a spectral support rule for pseudo-differential operators in combination with pointwise estimates in terms of maximal functions.

Johnsen, Jon

2010-01-01

335

Connectivity within and among a network of temperate marine reserves.  

Science.gov (United States)

Networks of marine reserves are increasingly being promoted as a means of conserving marine biodiversity. One consideration in designing systems of marine reserves is the maintenance of connectivity to ensure the long-term persistence and resilience of populations. Knowledge of connectivity, however, is frequently lacking during marine reserve design and establishment. We characterise patterns of genetic connectivity of 3 key species of habitat-forming macroalgae across an established network of temperate marine reserves on the east coast of Australia and the implications for adaptive management and marine reserve design. Connectivity varied greatly among species. Connectivity was high for the subtidal macroalgae Ecklonia radiata and Phyllospora comosa and neither species showed any clear patterns of genetic structuring with geographic distance within or among marine parks. In contrast, connectivity was low for the intertidal, Hormosira banksii, and there was a strong pattern of isolation by distance. Coastal topography and latitude influenced small scale patterns of genetic structure. These results suggest that some species are well served by the current system of marine reserves in place along this temperate coast but it may be warranted to revisit protection of intertidal habitats to ensure the long-term persistence of important habitat-forming macroalgae. Adaptively managing marine reserve design to maintain connectivity may ensure the long-term persistence and resilience of marine habitats and the biodiversity they support. PMID:21625388

Coleman, Melinda A; Chambers, Justine; Knott, Nathan A; Malcolm, Hamish A; Harasti, David; Jordan, Alan; Kelaher, Brendan P

2011-01-01

336

MEJORAMIENTO DE TRIGOS HARINEROS (Triticum aestivum L. EN LA ZONA CENTRO SUR DE CHILE: CONTENIDO Y PRODUCCIÓN DE PROTEINA, Y VOLUMEN DE SEDIMENTACIÓN EN TRIGOS INVERNALES, ALTERNATIVOS Y PRIMAVERALES Genetic improvement of bread wheat (Triticum aestivum L. in the South Central zone of Chile: Protein content, production and sedimentation volume of winter, alternative and spring wheats  

Directory of Open Access Journals (Sweden)

Full Text Available Se realizaron cuatro experimentos de campo con diez variedades de trigos de invierno y hábito alternativo (grupo 1, y cuatro experimentos con once variedades de trigos de primavera (grupo 2, para evaluar el porcentaje y producción de proteína del grano, y el volumen de sedimentación. Los genotipos fueron desarrollados en el Proyecto de Mejoramiento de Trigo del Instituto de Investigaciones Agropecuarias (INIA, Centro Regional de Investigación Quilamapu. Lilifén fue la primera variedad mejorada en el grupo 1, y Mexifén en el grupo 2; por lo tanto ambas fueron usadas como referencia. Los experimentos se llevaron a cabo en suelos Andisoles del Campo Experimental Santa Rosa (INIA, Chillán, Chile, desde el año 1995 a 1998. Los porcentajes medios de proteína de las variedades de los grupos 1 y 2 fueron 9,6 %, y 10,8%, respectivamente. El promedio de producción de proteína de las variedades del grupo 1 fue 894,6 kg ha-1 mientras que en el grupo 2 este valor fue 968,4 kg ha-1. Los valores medios para sedimentación fueron 3,4 mL en el grupo 1 y 4,3 mL en el grupo 2. En relación a las variedades, los resultados demostraron que el trabajo de mejoramiento de trigo realizado entre 1968 y 1993 fue más exitoso en mejorar el contenido de proteína del grano que su calidadFour field experiments with ten winter and alternative varieties (group 1 and four experiments with eleven spring wheat varieties (group 2, were carried out to assess grain protein percentage, grain production and sedimentation volume. The tested genotypes were developed at the Quilamapu Wheat Breeding Program, Institute of Agricultural Research, INIA. Lilifen was the first breed variety improved in group 1, and Mexifen in group 2; as such both were used as references. The experiments were carried out in Andisoil soils at the Santa Rosa Experimental Field, Chillán, Chile, from 1995 to 1998. The mean protein percentage of varieties of groups 1 and 2 were 9.6 and 10.8%, respectively. The average protein production in group 1 was 894.6 kg ha-1, while in group 2 was 968.4 kg ha-1. The average sedimentation values were 3.4 mL in group 1 and 4.3 mL in group 2. With regard to varieties, results showed that breeding work carried out between 1968 and 1993 was more successful at improving protein content rather than quality.

Mario Mellado Z.

2001-04-01

337

MEJORAMIENTO DE TRIGOS HARINEROS (Triticum aestivum L.) EN LA ZONA CENTRO SUR DE CHILE: CONTENIDO Y PRODUCCIÓN DE PROTEINA, Y VOLUMEN DE SEDIMENTACIÓN EN TRIGOS INVERNALES, ALTERNATIVOS Y PRIMAVERALES / Genetic improvement of bread wheat (Triticum aestivum L.) in the South Central zone of Chile: Protein content, production and sedimentation volume of winter, alternative and spring wheats  

Scientific Electronic Library Online (English)

Full Text Available SciELO Chile | Language: Spanish Abstract in spanish Se realizaron cuatro experimentos de campo con diez variedades de trigos de invierno y hábito alternativo (grupo 1), y cuatro experimentos con once variedades de trigos de primavera (grupo 2), para evaluar el porcentaje y producción de proteína del grano, y el volumen de sedimentación. Los genotipos [...] fueron desarrollados en el Proyecto de Mejoramiento de Trigo del Instituto de Investigaciones Agropecuarias (INIA), Centro Regional de Investigación Quilamapu. Lilifén fue la primera variedad mejorada en el grupo 1, y Mexifén en el grupo 2; por lo tanto ambas fueron usadas como referencia. Los experimentos se llevaron a cabo en suelos Andisoles del Campo Experimental Santa Rosa (INIA), Chillán, Chile, desde el año 1995 a 1998. Los porcentajes medios de proteína de las variedades de los grupos 1 y 2 fueron 9,6 %, y 10,8%, respectivamente. El promedio de producción de proteína de las variedades del grupo 1 fue 894,6 kg ha-1 mientras que en el grupo 2 este valor fue 968,4 kg ha-1. Los valores medios para sedimentación fueron 3,4 mL en el grupo 1 y 4,3 mL en el grupo 2. En relación a las variedades, los resultados demostraron que el trabajo de mejoramiento de trigo realizado entre 1968 y 1993 fue más exitoso en mejorar el contenido de proteína del grano que su calidad Abstract in english Four field experiments with ten winter and alternative varieties (group 1) and four experiments with eleven spring wheat varieties (group 2), were carried out to assess grain protein percentage, grain production and sedimentation volume. The tested genotypes were developed at the Quilamapu Wheat Bre [...] eding Program, Institute of Agricultural Research, INIA. Lilifen was the first breed variety improved in group 1, and Mexifen in group 2; as such both were used as references. The experiments were carried out in Andisoil soils at the Santa Rosa Experimental Field, Chillán, Chile, from 1995 to 1998. The mean protein percentage of varieties of groups 1 and 2 were 9.6 and 10.8%, respectively. The average protein production in group 1 was 894.6 kg ha-1, while in group 2 was 968.4 kg ha-1. The average sedimentation values were 3.4 mL in group 1 and 4.3 mL in group 2. With regard to varieties, results showed that breeding work carried out between 1968 and 1993 was more successful at improving protein content rather than quality.

Mario, Mellado Z..

338

The importance of the timing of winter-spring plankton blooms to exosystem productivity  

Energy Technology Data Exchange (ETDEWEB)

The timing of winter-spring phytoplankton blooms in temperate and high latitudes varies by as much as 6 weeks among years, being tied closely to the amount of solar insolation received. One effect of this variation is that water temperature and its effect on the matabolic rate of pelagic and benthic consumers will vary accordingly. We have constructed a simulation model based on 15 years of data on water temperatures and solar insolation not only to predict the timing of the winter-spring plankton bloom in coastal waters near Boothbay Harbor, Maine, but to investigate the various processes that are important in carbon flow through the ecosystem. The model has shown that variable bloom timing results in blooms occurring over a range of relatively cold water temperatures (ca. -1 to 5[degrees]C) and that the water temperature during and following the bloom is of paramount importance to the partitioning of the primary production into higher pelagic and benthic trophic levels. Blooms occurring in waters at or near 0[degrees]C may be accompanied by very low metabolism of both pelagic and benthic consumers. These results could have significant implications for how we view oceanographic processes ranging from fisheries production to the global carbon cycle.

Cammen, L.M.; Townsend, D.W. (Bigelow Lab. for Ocean Sciences, Boothbay Harbor, ME (United States)); Campbell, D.E. (Maine Dept. of Marine Resources, W. Boothbay Harbor, ME (United States))

1990-01-09

339

An approach to the determination of winter chill requirements for different Ribes cultivars.  

Science.gov (United States)

Winter chilling is critical for flowering and fruiting of many temperate fruits, with evidence that blackcurrant (Ribes nigrum L.) cropping has been adversely affected by warm winters. Accurate models of chill accumulation in blackcurrant are required so that breeding strategies can be formulated for the generation of new cultivars with resilience to future climates. Existing models for chill accumulation have largely been derived from statistical correlation; here we report the derivation of improved models for blackcurrant using controlled environment treatments. Hardwood cuttings from a diverse set of cultivars were exposed to constant or varying chilling temperatures and the effects on bud break after transfer to a warm, permissive environment evaluated. The impact of different combinations of temperature and chilling periods were described in terms of their overall 'Effectiveness' (E). Clear genotypic differences were found, with excessive chilling often inhibiting bud break. There was a significant interaction between observed chilling response and the period of low temperature exposure. A number of chilling models to explain observed interactions between chilling temperature and time of exposure on bud break were compared; the most effective involved an optimal response to increasing chill accumulation. The effects of varying temperatures during chilling on bud break were complex, with warm temperature breaks substantially inhibiting bud development and cooler temperature breaks tending to enhance bud burst. The relevance of these models to generic studies of endodormancy is discussed, together with their potential application to the development of phenotyping screens for future breeding using diverse blackcurrant germplasm. PMID:22512943

Jones, H G; Hillis, R M; Gordon, S L; Brennan, R M

2013-01-01

340

Temperate Ice Depth Sounding Radar (TIDSoR)  

Science.gov (United States)

Glaciers in several parts of the world are reported to be retreating and thinning rapidly over the last few years. A key variable in the study of glacier dynamics is ice thickness. A few attempts have been made to develop airborne sounding radars for temperate-ice thickness measurements [Arcone et al., 2000]. There is an urgent need for compact radar for routine ice thickness measurements from ground-based and airborne platforms. Radars (Radio Detection and Ranging) have been widely used to measure ice thickness in Greenland and Antarctica. However, the radars used in these areas operate in the VHF and UHF part of the electromagnetic spectrum. Due to the composition of temperate ice, the attenuation and back-scatter from large pockets of water makes UHF and VHF ineffective in sounding of its thickness. Radars operating in lower part of the HF spectrum are required for sounding temperate ice. We are designing and developing a Temperate Ice Depth-Sounding Radar (TIDSoR) that can penetrate through the water pockets and provide a more accurate measurement of the ice thickness. TIDSoR is a light-weight system for ground-based operations in mountainous terrain or aerial surveys in which weight is an important factor, such as in an UAV. TIDSoR operates on two channels in the HF spectrum using two-linear, frequency-modulated chirp waveforms. The two chirp frequency ranges are 7 to 8 MHz and 13.5 to 14.5 MHz. The radar will operate from a 12-V battery and is designed to weigh less than 2 kg, excluding the battery. The radar consists of three main sections: Digital, RF and antenna. The digital-section generates the transmitter waveforms, timing and control signals, and digitizes processes and stores the received signal. The RF-section consists of a transmitter with a 20-W peak-power amplifier, band-pass filters, and a switching system for a shared antenna. The receiver consists of a blanking switch, a limiter, a low-noise amplifier, a band-pass filter and a data acquisition system to store the acquired data. At HF, a physically large-antenna is needed. TIDSoR takes advantage of the helix antenna concept to minimize its physical dimensions and weight. Moreover, the ability to achieve different polarizations (linear, circular and elliptical) was considered to maximize the performance of the radar system. Arcone, S. A., Lawson, D. E., Moran, M. and Delaney, A. J., 2000, 12-100-MHz profiles of ice depth and stratigraphy of three temperate glaciers. In: Proc. GPR 2000, Eighth Intl. Conf. Ground-Penetrating Radar, Gold Coast, Austral., 23-26 May, 2000.

Jara, V.; Player, K.; Gogineni, S.; Rodriguez, F.; Thompson, L.

2007-12-01

 
 
 
 
341

On microstructure and performance of tempered high-boron high-speed steel roll  

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Full Text Available Influences of the tempering temperature on the microstructure, mechanical property and wear resistance of High-Boron High Speed Steel (HBHSS roll materials were investigated by means of optical microscopy, scanning electron microscopy (SEM, X-ray diffraction, hardness measurement, impact tester, tensile tester and pin abrasion tester. The results show that the as-cast structure of HBHSS consists of a great amount of martensite and M2(B,C and a few retained austenites and M23(B,C6. After solution treated at 1,050 °C and followed by oil cooling, the amount of M23(B,C6 carbo-borides in quenched HBHSS increases obviously and the macrohardness of the quenched HBHSS is 66 HRC, which is very close to the 65.8 HRC of as-cast HBHSS. On the whole, the hardness of HBHSS alloy shows a trend of slight decrease with increasing tempering temperature when tempered below 500 °C. While when above 500 °C, the hardness increases slightly as the tempering temperature increases and reaches a peak at 525 °C and then decreases obviously. The impact toughness of HBHSS has a tendency to increase as the tempering temperature increases. Tempering can improve the tensile strength and elongation of HBHSS, but a higher tempering temperature causes a slight decrease in both tensile strength and elongation. Excellent wear resistance can be obtained by tempering at 500 to 550 °C.

Fu Hanguang

2012-08-01

342

The effects of boro-tempering heat treatment on microstructural properties of ductile iron  

International Nuclear Information System (INIS)

In this study, the effects of boro-tempering heat treatment on microstructural properties of ductile iron were investigated. Test samples with dimensions of 10 x 10 x 55 mm were boronized at 900 oC for 1, 3 and 5 h and then tempered at four different temperatures (250, 300, 350 and 450 oC) for 1 h. Both optical microscopy and scanning electron microscopy were used to reveal the microstructural details of coating and matrix of boro-tempered ductile iron. X-ray diffraction was used to determine the constituents of the coating layer. The boride layer formed on the surface of boro-tempered ductile cast iron is tooth shape form and consisted of FeB and Fe2B phases. The thickness of boride layer increases as the boronizing time increases and tempering temperature decreases. Tempering temperature is more effective than boronizing time on the matrix structure. Boro-tempering heat treatment reduces the formation of lower and upper ausferritic matrix temperature according to classical austempering. This causes formation of upper ausferritic matrix in the sample when tempered at 300 oC. This is in contrast to general case which is the formation of lower ausferritic matrix via austempering at this temperature.

343

Toughness and austenite stability of modified 9Cr-1Mo welds after tempering  

International Nuclear Information System (INIS)

The influence of tempering treatments on toughness and austenite stability was conducted on modified 9Cr-1Mo welds. Deteriorated impact toughness was noticed for the welds tempered between 450 and 610 C for 1 h, in which the peak hardness and the lowest impact energy occurred at 540 C. The impact toughness of the welds increased rapidly at tempering temperatures above 680 C, and the associated fracture surface exhibited mainly dimple fractures for 750 C/1 h tempered welds, in contrast to quasi-cleavage for 540 C/1 h welds. Retained austenite at martensite interlath boundaries was found to be mechanically stabilized by transformation stresses in the welds tempered at lower temperatures. It could also be transformed to untempered martensite upon cooling if the stresses were relieved to a certain degree by proper selection of temperature and time combinations in tempering. For welds tempered at higher temperatures, e.g. 750 C, the elimination of transformation stresses and the isothermal transformation of retained austenite to ferrite proceeded simultaneously. As a result, no martensitic transformation upon cooling could be found for such welds. The transformation of austenite to untempered martensite would certainly contribute to the minimum toughness of the weld after being tempered at 540 C/1 h. (orig.)

344

Effect of tempering temperature on microstructure and mechanical properties of high boron white cast iron  

Directory of Open Access Journals (Sweden)

Full Text Available The effect of different tempering temperatures on the microstructure and mechanical properties of air-quenched high boron white cast iron was studied. The results indicate that the high boron white cast iron comprises dendritic matrix and inter-dendritic M2B boride; and the matrix comprises martensite and pearlite. After quenching in the air, the matrix is changed into lath martensite; but only 1-?m-size second phase exists in the matrix. After tempering, another second phase of several tens of nanometers is found in the matrix, and the size and quantity increase with an increase in tempering temperature. The two kinds of second precipitation phase with different sizes in the matrix have the same chemical formula, but their forming stages are different. The precipitation phase with larger size forms during the austenitizing process, while the precipitation phase with smaller size forms during the tempering process. When tempered at different temperatures after quenching, the hardness decreases with an increase in the tempering temperature, but it increases a little at 450 ? due to the precipitation strengthening effect of the second phase, and it decreases greatly due to the martensite decomposition above 450 ?. The impact toughness increases a little when tempered below 300 ?, but it then decreases continuously owing to the increase in size and quantity of the secondary precipitate above 300 ?. Considered comprehensively, the optimum tempering temperature is suggested at 300 ? to obtain a good combination of hardness and toughness.

Liu Zhongli

2012-11-01

345

Impurity effect on tendency to temper brittleness in heat resistant Cr-Mo-V steel  

International Nuclear Information System (INIS)

Effect of sulfur-, phosphorus-, copper-, arsenic-, autimony-, tin impurities on temper brittleness in 25Kh1M1F steel of 18 compositions has beep investigated. It is concluded that only phospohorus and antimony influence noticeably on tendency to temper brittleness in fine-grained steel, at the same time influence of phosphorus is much greater

346

Surface stress meters utilising the optical waveguide effect of chemically tempered glasses  

Science.gov (United States)

Chemical tempering is increasing the areas of glass application in the wristwatch, glass and electronic industries. The optical waveguide effect in the surface layer of chemically tempered glass is a useful tool for measuring surface stress for quality and process control purposes. The theoretical basis, measuring techniques and apparatus are briefly reviewed.

Kishii, Toru

347

Winter barley mutants created in the Ukraine  

International Nuclear Information System (INIS)

Full text: Increasing fodder and protein production is one of the objectives of the development of agriculture in Ukraine. Higher productivity of fodder crops, due to new highly productive varieties, is the means to meet this aim. Winter barley is an important crop for fodder purposes. The climate of the Ukraine is favourable for growing this crop. The areas used for the growth of winter barley are however, small (500,000-550,000 ha) and there is a shortage of good quality varieties. The main aim of the work was therefore to create new varieties of highly productive winter barley, of good quality. The new varieties and mutation lines of winter barley were created under the influence of water solutions of N-nitroso-N-methylurea (NMH - 0,012, 0,005%), N-nitroso-N-ethylurea (NEH - 0,05; 0.025; 0,012%) ethyleneimine (EI - 0,02; 0,01; 0,005%) on winter barley seeds of the varieties of local and foreign selections. On the basis of many years of investigations (1984-94) the following mutations were described: hard-grained, winter-hardiness, earliness, middle-maturity, late-maturity, wide and large leaves, narrow leaves, multinodal, great number of leaves, great number of flowers, strong stem (lodging resistant), tallness, semi-dwarfness, dwarfness, and high productivity. Particularly valuable are mutants with high productivity of green bulk. Their potential yield is 70 t/ha. As a result of the work two varieties of winter barley 'Shyrokolysty' and 'Kormovy' were released into the State register of plant varieties of the Ukraine. The other valuable mutant genotypes are used in cross breeding programmes. (author)

348

Standardized precipitation index zones for Mexico  

Energy Technology Data Exchange (ETDEWEB)

Precipitation zone systems exists for Mexico based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El nino. An empirical set of seven exclusively Mexican and six shared zones was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zones edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed. [Spanish] Existen varios sistemas de zonificacion de Mexico basados en la estacionalidad, cantidad de precipitacion, climas y divisiones geograficas, pero ninguno es conveniente para el estudio de la relacion de la precipitacion con fenomenos tales como El Nino. En este trabajo se presenta un conjunto de siete zonas empiricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imagenes de SPI (Indice Estandarizado de la Precipitacion), desde 1940 a 1989: una serie de 582 imagenes mensuales (SPI-12), una series de 50 imagenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imagenes (SPI-6) de meses de verano (mayo a octubre). Al examinar imagenes de componentes principales y de clasificaciones no supervisadas, se descubrio que las tres series tenian una zonificacion similar. Un conjunto de campos de entrenamiento fue utilizado para clasificar las tres series. Despues de doce tanteos las zonas resultantes, presentadas aqui, fueron casi identicas para las tres series, con variaciones principalmente alrededor de los bordes. Un conjunto de zonas sencillas definidas por pocos vertices puede ser usado para operaciones practicas. En general, las zonas son homogeneas, casi sin mezcla de zonas y con pocos fragmentos de una zona en otra. Estas zonas se comparan con un mapa previamente publicado de zonas climaticas. Se mencionan posibles aplicaciones.

Giddings, L.; Soto, M. [Instituto de Ecologia, A.C., Xalapa, Veracruz (Mexico); Rutherford, B.M.; Maarouf, A. [Faculty of Environmental Studies, York University, Toronto, Ontario (Canada)

2005-01-01

349

Standardized Precipitation Index Zones for México  

Scientific Electronic Library Online (English)

Full Text Available SciELO Mexico | Language: English Abstract in spanish Existen varios sistemas de zonificación de México basados en la estacionalidad, cantidad de precipitación, climas y divisiones geográficas, pero ninguno es conveniente para el estudio de la relación de la precipitación con fenómenos tales como El Niño. En este trabajo se presenta un conjunto de siet [...] e zonas empíricas exclusivamente mexicanas y seis compartidas, derivadas de tres series de imágenes de SPI (Índice Estandarizado de la Precipitación), desde 1940 a 1989: una serie de 582 imágenes mensuales (SPI-12), una serie de 50 imágenes (SPI-6) de meses de invierno (noviembre a abril), y otra de 50 imágenes (SPI-6) de meses de verano (mayo a octubre). Al examinar imágenes de componentes principales y de clasificaciones no supervisadas, se descubrió que las tres series tenían una zonificación similar. Un conjunto de campos de entrenamiento fue utilizado para clasificar las tres series. Después de doce tanteos las zonas resultantes, presentadas aquí, fueron casi idénticas para las tres series, con variaciones principalmente alrededor de los bordes. Un conjunto de zonas sencillas definidas por pocos vértices puede ser usado para operaciones prácticas. En general, las zonas son homogéneas, casi sin mezcla de zonas y con pocos fragmentos de una zona en otra. Estas zonas se comparan con un mapa previamente publicado de zonas climáticas. Se mencionan posibles aplicaciones. Abstract in english Precipitation zone systems exist for México based on seasonality, quantity of precipitation, climates and geographical divisions, but none are convenient for the study of the relation of precipitation with phenomena such as El Niño. An empirical set of seven exclusively Mexican and six shared zones [...] was derived from three series of Standardized Precipitation Index (SPI) images, from 1940 through 1989: a whole-year series (SPI-12) of 582 monthly images, a six month series (SPI-6) of 50 images for winter months (November through April), and a six-month series (SPI-6) of 50 images for summer months (May through October). By examination of principal component and unsupervised classification images, it was found that all three series had similar zones. A set of basic training fields chosen from the principal component images was used to classify all three series. The resulting thirteen zones, presented in this article, were found to be approximately similar, varying principally at zone edges. A set of simple zones defined by just a few vertices can be used for practical operations. In general the SPI zones are homogeneous, with almost no mixture of zones and few outliers of one zone in the area of others. They are compared with a previously published map of climatic regions. Potential applications for SPI zones are discussed

L., GIDDINGS; M., SOTO; B. M., RUTHERFORD; A., MAAROUF.

2005-01-01

350

Effects of elevated atmospheric CO2, prolonged summer drought and temperature increase on N2O and CH4 fluxes in a temperate heathland  

DEFF Research Database (Denmark)

In temperate regions, climate change is predicted to increase annual mean temperature and intensify the duration and frequency of summer droughts, which together with elevated atmospheric carbon dioxide (CO2) concentrations, may affect the exchange of nitrous oxide (N2O) and methane (CH4) between terrestrial ecosystems and the atmosphere. We report results from the CLIMAITE experiment, where the effects of these three climate change parameters were investigated solely and in all combinations in a temperate heathland. Field measurements of N2O and CH4 fluxes took place 1–2 years after the climate change manipulations were initiated. The soil was generally a net sink for atmospheric CH4. Elevated temperature (T) increased the CH4 uptake by on average 10 ?g C m?2 h?1, corresponding to a rise in the uptake rate of about 20%. However, during winter elevated CO2 (CO2) reduced the CH4 uptake, which outweighed the positive effect of warming when analyzed across the study period. Emissions of N2O were generally low (

Carter, Mette Sustmann; Ambus, Per

2011-01-01

351

An Inventory of Terrestrial Mammals at National Parks in the Northeast Temperate Network and Sagamore Hill National Historic Site  

Science.gov (United States)

An inventory of mammals was conducted during 2004 at nine national park sites in the Northeast Temperate Network (NETN): Acadia National Park (NP), Marsh-Billings-Rockefeller National Historical Park (NHP), Minute Man NHP, Morristown NHP, Roosevelt-Vanderbilt National Historic Site (NHS), Saint-Gaudens NHS, Saugus Iron Works NHS, Saratoga NHP, and Weir Farm NHS. Sagamore Hill NHS, part of the Northeast Coastal and Barrier Network (NCBN), was also surveyed. Each park except Acadia NP was sampled twice, once in the winter/spring and again in the summer/fall. During the winter/spring visit, indirect measure (IM) sampling arrays were employed at 2 to 16 stations and included sampling by remote cameras, cubby boxes (covered trackplates), and hair traps. IM stations were established and re-used during the summer/fall sampling period. Trapping was conducted at 2 to 12 stations at all parks except Acadia NP during the summer/fall period and consisted of arrays of small-mammal traps, squirrel-sized live traps, and some fox-sized live traps. We used estimation-based procedures and probabilistic sampling techniques to design this inventory. A total of 38 species was detected by IM sampling, trapping, and field observations. Species diversity (number of species) varied among parks, ranging from 8 to 24, with Minute Man NHP having the most species detected. Raccoon (Procyon lotor), Virginia Opossum (Didelphis virginiana), Fisher (Martes pennanti), and Domestic Cat (Felis silvestris) were the most common medium-sized mammals detected in this study and White-footed Mouse (Peromyscus leucopus), Northern Short-tailed Shrew (Blarina brevicauda), Deer Mouse (P. maniculatus), and Meadow Vole (Microtus pennsylvanicus) the most common small mammals detected. All species detected are considered fairly common throughout their range including the Fisher, which has been reintroduced in several New England states. We did not detect any state or federal endangered or threatened species.

Gilbert, A.T.; O'Connell, A.F., Jr.; Annand, E.M.; Talancy, N.W.; Sauer, J.R.; Nichols, J.D.

2008-01-01

352

Carbon dioxide partial pressure and 13C content of north temperate and boreal lakes at spring ice melt  

Science.gov (United States)

Carbon dioxide (CO2) accumulates under lake ice in winter and degasses to the atmosphere after ice melt. This large springtime CO2 pulse is not typically considered in surface-atmosphere flux estimates, because most field studies have not sampled through ice during late winter. Measured CO2 partial pressure (pCO2) of lake surface water ranged from 8.6 to 4,290 Pa (85-4,230 ??atm) in 234 north temperate and boreal lakes prior to ice melt during 1998 and 1999. Only four lakes had surface pCO2 less than or equal to atmospheric pCO2, whereas 75% had pCO2 >5 times atmospheric. The ??13CDIC (DIC = ??CO2) of 142 of the lakes ranged from -26.28??? to +0.95.???. Lakes with the greatest pCO2 also had the lightest ??13CDIC, which indicates respiration as their primary CO2 source. Finnish lakes that received large amounts of dissolved organic carbon from surrounding peatlands had the greatest pCO2. Lakes set in noncarbonate till and bedrock in Minnesota and Wisconsin had the smallest pCO2 and the heaviest ??13CDIC, which indicates atmospheric and/or mineral sources of C for those lakes. Potential emissions for the period after ice melt were 2.36 ?? 1.44 mol CO2 m-2 for lakes with average pCO2 values and were as large as 13.7 ?? 8.4 mol CO2 m-2 for lakes with high pCO2 values.

Striegl, R.G.; Kortelainen, P.; Chanton, J.P.; Wickland, K.P.; Bugna, G.C.; Rantakari, M.

2001-01-01

353

Temporal and spatial heterogeneity in lacustrine ?13CDIC and ?18ODO signatures in a large mid-latitude temperate lake  

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Full Text Available Modelling limnetic carbon processes is necessary for accurate global carbon models and stable isotope analysis can provide additional insight of carbon flow pathways. This research examined the spatial and temporal complexity of carbon cycling in a large temperate lake. Dissolved inorganic carbon (DIC is utilised by photosynthetic organisms and dissolved oxygen (DO is used by heterotrophic organisms during respiration. Thus the spatial heterogeneity in the pelagic metabolic balance in Loch Lomond, Scotland was investigated using a combined natural abundance isotope technique. The isotopic signatures of dissolved inorganic carbon (?13CDIC and dissolved oxygen (?18ODO were measured concurrently on four different dates between November 2004 and September 2005. We measured isotopic variation over small and large spatial scales, both horizontal distance and depth. ?13CDIC and ?18ODO changed over a seasonal cycle, becoming concurrently more positive (negative in the summer (winter months, responding to increased photosynthetic and respiratory rates, respectively. With increasing depth, ?13CDIC became more negative and ?18ODO more positive, reflecting the shift to a respiration-dominated system. The horizontal distribution of ?13CDIC and ?18ODO in the epilimnion was heterogeneous. In general, the south basin had the most positive ?13CDIC, becoming more negative with increasing latitude, except in winter when the opposite pattern was observed. Areas of local variation were often observed near inflows. Clearly ?13CDIC and ?18ODO can show large spatial heterogeneity, as a result of varying metabolic balance coupled with inflow proximity and thus single point sampling to extrapolate whole lake metabolic patterns can result in error when modelling large lake systems Whilst we advise caution when using single point representation, we also show that this combined isotopic approach has potential to assist in constructing detailed lake carbon models.

Jane DRUMMOND

2010-08-01

354

Enhanced Mechanical Properties of a Hot-Stamped Advanced High-Strength Steel via Tempering Treatment  

Science.gov (United States)

The hot stamping process has an extensive range of applications due to its advantages over the traditionally used stamping techniques developed in the past. To enhance the mechanical properties of the indirectly hot-stamped parts, the quenching and partitioning (Q&P) process has been recently applied on boron-alloyed steel. In the current research, it was observed that the tempering treatment on the directly hot-stamped boron steel resulted in better mechanical properties and higher formability index compared with the reported results using the Q&P process. The nano-carbide formation and the dislocation annihilation during the tempering treatment were suggested as the evident reasons for the occurrence of the mentioned robust properties. The ease of the practical implementation of the tempering route together with the markedly enhanced mechanical properties of the tempered parts make the suggested method privileged. Additionally, the variations in the yield strength before and after tempering were quantitatively evaluated.

Naderi, M.; Abbasi, M.; Saeed-Akbari, A.

2013-04-01

355

Influence of tempering on microstructure and hardness of high-temperature 9%Cr-steels  

International Nuclear Information System (INIS)

The influences of temperature and duration of tempering on hardness and microstructure were investigated at high-temperature martensitic and low-carbon steels with 9% chrome and the further alloying elements molybdenium, vanadium, niobium and partially tungsten. After austenitizing and subsequent air cooling the steels were tempered at temperatures below, at and above Ac1b for different times and finally a hardness test was performed. Making use of the temperature dependence of the hardness tempering diagrams were constructed and the Hollomon-Jaffe-Parameter on the three steels was determined within its application limits. Micrographs of the structure shows the formation of the carbides and the martensite. At tempering temperatures below Ac1b a decrease of hardness occurs, above Ac1b, a hardness rise due to the partial austenitizing was obtained. While hardening below Ac1b, the tempering quality increases from P 91, NF 616 to E 911. (orig.)

356

Effect of tempering on microstructure and mechanical properties of a non-quenched bainitic steel  

Energy Technology Data Exchange (ETDEWEB)

The effect of tempering on the microstructure and mechanical properties of a non-quenched (NQ) bainitic steel was investigated by optical microscopy, X-ray diffractometry, scanning electronic microscope (SEM) and transmission electronic microscopy (TEM). The results show that the NQ steel which has been investigated is granular bainite composed of bainitic ferrite lath, retained austenite film and island of austenite and martensite (M/A island) before tempering. The amount of retained austenite decreases with the rise of tempering, slowly before 400 deg. C, sharply at 450 deg. C, and it is close to 0 at 600 deg. C. When tempered at 350 deg. C, this kind of NQ steel has the optimum mechanical properties because of M/A islands partly decomposition, especially for the martensite in the M/A islands. However, when tempered at 450 deg. C, it appears brittleness, which results from carbides distributing along prior austenite grains because M/A island is largely decomposed.

Luo Yi, E-mail: luoyileyi@163.com [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Peng Jinmin; Wang Hongbin; Wu Xiaochun [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

2010-06-15

357

33 CFR 100.109 - Winter Harbor Lobster Boat Race, Winter Harbor, ME.  

Science.gov (United States)

...Harbor Lobster Boat Race, Winter Harbor...Harbor Lobster Boat Race, Winter Harbor...modify, or cancel the race as conditions or...regulated area should contact the Coast...this regulation and other applicable laws...section will be in effect the second...

2010-07-01

358

WINTER HARDINESS AND EFFICIENCY OF THE WINTER RAPE DEPENDING ON TERMS AND NORMS OF CROPS ????????????? ? ?????????????? ??????? ????? ? ??????????? ?? ?????? ? ???? ??????  

Directory of Open Access Journals (Sweden)

Full Text Available In this article, the results of researches of the influ-ence of terms and norms of crops of a winter rape on growth and development of plants, winter hardi-ness and productivity of cultures in the changed environmental conditions of Rostov region are re-sulted

Fetyukhin I. V.

2012-01-01

359

Payment mechanisms for winter road maintenance services  

Directory of Open Access Journals (Sweden)

Full Text Available In countries with severe winters a major part of the annual budget for road maintenance is allocated on performance of winter road maintenance tasks. Finding appropriate remuneration forms to compensate entrepr