bluuebunny/crossref_metadata_2025 huggingface dataset:
Research and Application of Dynamic Substitution Control of Actuators in Flatness Control of Cold Rolling Mill
Authors: Peng‐fei Wang , Dian‐hua Zhang , Xu Li , Wen‐xue Zhang
Published: December 2010

The work roll bending control has a strong ability to eliminate the symmetrical flatness defects of strip. However, if the incoming strip is coming with severe symmetrical flatness defects, it happens that the position limit of work roll bending is prone to be reached or exceeded during the execution of the displacement, resulting in the residual symmetrical flatness defects without further elimination, as well as a limited flatness control process. Abilities of work roll bending and intermediate roll bending / shifting for flatness control have been analyzed based on the actuator efficiencies for the purpose of solving the problem of work roll bending control reaching threshold. Meanwhile, a self‐learning determination model of actuator efficiency factors, which can be utilized to determine the actuator efficiency factors online accurately, was developed from the measurement data extracted from the rolling mill. Models of intermediate roll bending and intermediate roll shifting substitution control in case of work roll bending control over‐limitation have been developed, in accordance with the practical conditions and the degree of work roll bending over‐limitation. Applications show that the substitution control can play an important role in the residual symmetrical flatness deviation control, which should have been removed completely by the work roll bending control.
Evaluation of the Austenite Recrystallization by Multideformation and Double Deformation Tests
Authors: Vervynckt S. , Verbeken K. , Thibaux P. , Houbaert Y.
Published: December 2010

A high amount of deformation below the non‐recrystallization temperature (Tnr) is a common industrial practice to achieve a good combination of toughness and strength in microalloyed steels. To combine the industrially relevant optimum combination of high productivity and product quality, an accurate knowledge of Tnr and the recrystallization kinetics is required. Although a lot of literature data is available on the recrystallization behaviour of microalloyed steels, correlations are often difficult to be made due to the effect of different experimental set‐ups and test schedules used to obtain this data. Although it would significantly improve the knowledge about these steels, so far, no systematic comparison has been presented in literature to correlate the different techniques one to another. In this study, different hot rolling simulation techniques and testing schedules were compared, within the experimental constraints of the used equipment, to determine the Tnr temperature of two microalloyed steels. Good agreement was found between the results from different test equipment. Furthermore, the results from the multideformation tests under continuous cooling conditions could be correlated with the results from isothermal double deformation tests.
Cementitious Phases in Ladle Slag
Authors: Adolfsson Daniel , Engström Fredrik , Robinson Ryan , Björkman Bo
Published: December 2010

Ladle slag is an internal by‐product generated within the steelmaking industry during the refining of steel. The realisation of beneficial inherent properties of ladle slag as a binder supplement or substitute material is believed to be advantageous with respect to both economy and environment for steelmakers. For this reason, the current study has focused on highlighting the properties of ladle slag that are pertinent to the formation of calcium aluminate hydrates. Three fractions of ladle slag, two of which were based on different slag formers, have been characterised using XRF, XRD and calorimetric analysis. Commonly known hydraulic minerals such as mayenite, tricalcium aluminate and dicalcium silicate were detected during analysis. An important aspect in the utilisation of ladle slag is the slag handling methodology. Therefore, this study also highlights and discusses the need to reconsider slag handling procedures concerning unnecessary exposure to weathering and the possible need for further processing of the slag in order to better employ the inherent hydraulic properties of this material.
The Numerical Prediction of the Titanium Carbide Distribution in the Blast Furnace During Tapping Process: A Preliminary Study
Authors: Lin Chung Hao , Cheng Wen Tung , Du Shan Wen
Published: December 2010

To prolong the campaign life of the furnace hearth for high demand in the steel market, the theme of preventing the hearth wall from erosion phenomenon is worthily studied for steel industry. The titanium carbide (TiC) concentration distributions in the blast furnace hearth can be used to suppress the erosion phenomenon of the hearth wall. In this work, we solve the momentum and the thermal‐energy‐balance equations, as well as the mass transfer equation with chemical reaction effects to investigate the TiC concentration profiles in the hearth of Port Kembla no. 5 blast furnace (PKBF5) by means of a computational fluid dynamics (CFD) package, Fluent (version 6.2). As shown in the results, the elephant foot erosion and pot‐like erosion in the hearth may be restrained based on the calculated TiC concentration distributions. Additionally, this work illustrates that deadman type may be inferred based on the calculated TiC concentration profiles when the blast furnace is revamped.
The Effect of Solid Particles on Liquid Viscosity
Authors: Wu Liushun , Ek Mattias , Song Minho , Sichen Du
Published: December 2010

The viscosities of solid‐liquid mixtures were experimentally determined for silicon oil‐paraffin system at room temperature and solid‐liquid oxide mixture at steelmaking temperature. The use of oil‐paraffin systems was to confirm the results of high temperature measurements, the experimental conditions being very difficult to control. The silicon oil‐ paraffin mixtures behaved Newtonian until the particle fraction reached 0.15. At this fraction, the mixture started deviate from Newtonian flow; though some average values could still be collected with very high uncertainty. Liquid‐2CaO.SiO2 mixtures and liquid‐MgO mixtures were studied at steelmaking temperature with carefully prepared particle fractions and well controlled conditions. Liquid‐2CaO.SiO2 mixture behaved Newtonian even when the particle fraction reached 0.1. The results of both room temperature measurements and steelmaking temperature measurements were used to examine the applicability of the existing models. Einstein‐Roscoe equation was found to be the only model applicably for the systems studied. No modification of the model parameter was found necessary, though the particles were not spherical.
Induction Hardening of Spur Gearwheels Made from 42CrMo4 Hardening and Tempering Steel by Employing Spray Cooling
Authors: Rodman Dmytro , Krause Christian , Nürnberger Florian , Bach Friedrich‐Wilhelm , Haskamp Klaus , Kästner Markus , Reithmeier Eduard
Published: December 2010

As a rule, induction surface hardening is carried out industrially by employing polymer solutions since these ensure a more homogeneous quench than immersion cooling in water. Besides reproducing the quenching process, the intention here is to minimise the hardening defects and the distortions arising from the heat treatment. Polymer solutions also have a few disadvantages which include, among others, poor environmental compatibility and handleability. Quenching by means of spray cooling provides an effective alternative. The purpose of the current investigation is to substitute the polymer solution by a water‐air spray in induction hardening equipment for surface hardening spur gearwheels made of 42CrMo4 hardening and tempering steel. The suitability of spray cooling was assessed by means of hardness measurements, residual stress conditions, distortion measurements and by metallographic examinations. Based on the analyses currently carried out, it was possible to show that the two‐phase spray cooling represents an alternative quenching method which produces comparable component properties.
Microstructural Changes after Control Rolling and Interrupted Accelerated Cooling Simulations in Pipeline Steel
Authors: Sanchez‐Mouriño Nuria , Petrov Roumen , Bae Jin‐Ho , Kim Kisoo , Kestens Leo A.I.
Published: December 2010

The γ‐α transformation and final microstructure in pipeline steel was studied by carrying out a number of physical simulations of industrial hot rolling schedules. Particularly, the effect of the reheating temperature, deformation and cooling parameters on the transformation temperatures and final grain size were considered with a goal to obtain an appropriate thermo‐mechanical processing route which will generate appropriate microstructures for pipeline applications. The CCT diagram of the steel was derived experimentally by means of dilatometric tests. Hot torsion experiments were applied in a multi‐deformation cycle at various temperatures in the austenite region to simulate industrial rolling schedules. By variation of the reheating temperature, equivalent strain, and accelerated cooling, different types of microstructures were obtained. It was found that the deformation increases the transformation temperatures whereas the higher cooling rates after deformation decrease them. Post‐deformation microstructure consists of fine bainitic‐ferrite grains with dispersed carbides and small amount of dispersed martensite/austenite islands which can be controlled by varying the reheating temperature, deformation and post‐deformation cooling. The detailed microstructure characteristics obtained from the present work could be used to optimize the mechanical properties, strength and toughness of pipeline steel grades by an appropriate control of the thermo‐mechanical processing.
Computational Fluid Dynamic (CFD) Simulations of Liquid Steel Infiltration in Ceramic Foam Structures. Part I: Fundamentals and Validation
Authors: Schwarze R. , Klostermann J. , Brücker Ch.
Published: December 2010

The infiltration of liquid TRIP steel into a porous zirconium dioxide foam ceramics is a possible production line for a new composite material. This composite is currently under investigation in a joint research project, which should explore the basic features and possible designs of the new material. The paper presents a pore‐scale model for the numerical simulation of the infiltration process. Such simulations should help to develop optimised production processes for the composite. The qualitative and quantitative performance of the model is evaluated by comparison of simulation results with data from corresponding water model experiments. Good agreement between the numerical and the experimental results is found.
The effects of annealing and acid hydrolysis on resistant starch level and the properties of cross‐linked RS4 rice starch
Authors: Song Ji‐Young , Park Jin‐Hee , Shin Malshick
Published: December 2010

The effects of ANN prior to cross‐linking of non‐wx rice starches on a RS level and granular shape were investigated to apply them for a fat replacer with RS in a liquid food system. Acid hydrolysis and sonication were also evaluated to improve RS quality. The RS level was also compared with AOAC and P/G methods. The RS levels of CRS analyzed with the AOAC method were higher than those analyzed with the P/G method, but the differences in the RS level of CRS affected an ANN condition and starch content during cross‐linking. When ANN was conducted at 50°C for 12 h using the AOAC method, and starch content (40%) used in cross‐linking was at 45°C for 3 h, the highest RS level of CRS treated with ANN was 69.4% compared to 38.3% RS level of CRS without ANN. The 1 h acid hydrolysis (pH 4.0) of CRS treated ANN increased 114.5% of the RS level (79.4% compared to 69.4% in CRS treated ANN), regardless of which analytical methods were used. CRS granules remained the same as native ones with a polygonal shape and A type crystallinity even after being treated with ANN, and acid hydrolysis. The sonication before cross‐linking reaction increased the RS level and prevented increase in size from aggregating CRS granules.
Desizing of untreated cotton fabric with the conventional and ultrasonic bath procedures by immobilized and native α‐amylase
Authors: Şahinbaşkan Burcu Yılmaz , Kahraman Memet Vezir
Published: December 2010

In this work, starch‐sized, untreated 100% cotton plain woven fabric was treated with native and immobilized α‐amylase enzyme in two different system (conventional and ultrasonic bath procedures) and time (15 and 30 min). Weight loss, the amount of removed starch, tensile properties, contact angle, and scanning electron micrograph morphology were investigated. Sonification and treatment time enhance the desizing performance. Free enzyme, treatment time, and ultrasound brings about a significant increase in the starch‐size removal along with a decrease in the retained strength values, regardless of the used fabric. Immobilized enzyme can be use many times which enables to improve environment friendly pretreatment processes for the textile industry.
Wnt Signaling Regulates Symmetry of Division of Neural Stem Cells in the Adult Brain and in Response to Injury
Authors: Piccin David , Morshead Cindi M.
Published: December 2010

Neural stem cells comprise a small population of subependymal cells in the adult brain that divide asymmetrically under baseline conditions to maintain the stem cell pool and divide symmetrically in response to injury to increase their numbers. Using in vivo and in vitro models, we demonstrate that Wnt signaling plays a role in regulating the symmetric divisions of adult neural stem cells with no change in the proliferation kinetics of the progenitor population. Using BAT-gal transgenic reporter mice to identify cells with active Wnt signaling, we demonstrate that Wnt signaling is absent in stem cells in conditions where they are dividing asymmetrically and that it is upregulated when stem cells are dividing symmetrically, such as (a) during subependymal regeneration in vivo, (b) in response to stroke, and (c) during colony formation in vitro. Moreover, we demonstrate that blocking Wnt signaling in conditions where neural stem cells are dividing symmetrically inhibits neural stem cell expansion both in vivo and in vitro. Together, these findings reveal that the mechanism by which Wnt signaling modulates the size of the stem cell pool is by regulating the symmetry of stem cell division.
A momentum explanation for the unsatisfactory Betz model prediction in highly loaded wind turbines
Authors: Georgiou D. P. , Theodoropoulos N. G.
Published: December 2010

The present study attempts to provide a direct explanation for the strong deviation between the predictions of the well‐known Betz model and the actual results for the performance of highly loaded wind turbines. The new model accounts for the inner and outer stream interaction (momentum and energy transfers) by reformulating the relevant one‐dimensional flow equations. This results in a very good prediction of the experimentally measured CT = f(a) relationship in ‘windmilling propeller’ tests. It is shown that although the maximum power coefficient is near that predicted by Betz, for rotor loadings beyond the ‘optimum’ point, this drops sharply (instead of remaining steady, near the CP = 0.5 value). Further analysis shows that the main contributor for this ‘efficiency’ degradation is the reduction in the mass flux through the turbine rotor, apparently because of the wake vortices that block its passage in the inner section. Copyright © 2010 John Wiley & Sons, Ltd.
Hydrothermal In Situ Synthesis of a Novel Three‐dimensional Tetrazole Coordination Polymer with Manganese Ions
Authors: Wang Wei , Fu Da‐Wei , Xu Xiong‐Bin , Ye Qiong
Published: December 2010

The hydrothermal reaction of benzotriazol‐1‐yl‐acetonitrile and Mn(ClO4)2·6H2O in the presence of NaN3 yielded almost colorless block‐shaped crystals of a novel three‐dimensional manganese coordination compound with benzotriazol‐1‐yl‐acetic acid and 1‐(1H‐tetrazol‐5‐ylmethyl)‐1H‐benzotriazole ligands, which were obtained by in situ hydrolysis and 2+3 cyclo‐additional reactions of the cyano group in Pyrex tube at 150 °C. In this compound azide, benzotriazol‐1‐yl‐acetic acid, and 1‐(1H‐tetrazol‐5‐ylmethyl)‐1H‐benzotriazole as multi‐dentate ligands coordinate to three crystallographically independent manganese atoms to form a novel three‐dimensional coordination polymer. Dielectric measurements show no dielectric anomaly within the temperature range of 120 K to 300 K.
Phenylimido Complexes of Technetium and Rhenium with Maleonitriledithiolate
Authors: Kuhn Bernd , Abram Ulrich
Published: December 2010

[Tc(NPh)Cl3(PPh3)2] or [Re(NPh)Cl3(PPh3)2] react with two equivalents of Na2mnt (mnt2– = 1,2‐dicyanoethene‐1,2‐dithiolate) with formation of anionic complexes of the composition [M(NPh)(mnt)2]–. The products can be isolated as large red blocks of their AsPh4+ salts. The complex anions contain square‐pyramidal coordinated metal atoms with the phenylimido ligands in apical positions. The M–N–C bonds are almost linear. A similar phenylimido complex with an additional amino group was synthesized from [Re(NC6H4‐4‐NH2)Cl3(PPh3)2]. The presence of such substituents may allow coupling of the metal complexes to biomolecules such as peptides, proteins, or sugars, provided the M=N bonds are sufficiently stable against hydrolysis.
Three New cpt‐Metal Complexes Displaying 0D, 1D, and 3D Topology Structures
Authors: Song Jiang‐Feng , Zhou Rui‐Sha , Zhang Jia , Xu Chun‐Yan , Li Yan‐Bing , Wang Biao‐Bing
Published: December 2010

Three new cpt‐metal complexes of different topology structures were synthesized by solvothermal methods [Hcpt = 4‐(4‐carboxyphenyl)‐1,2,4‐triazole]. The structure of [Mn(cpt)2·2H2O] (1) is essentially 0D monomeric, but extended into a 2D supramolecular network through cross‐linking hydrogen bonds. In [Cu(cpt)(OH)·2H2O]·2H2O (2), the hydroxo groups as well as cpt ligands join the copper ions into an infinite polymeric [Cu(μ‐cpt)(μ‐OH)] chain, which is interconnected into a 3D supramolecular network with different oriented channels by 1D water chains. The complex [Zn(cpt)2]·0.5DMF·CH3CH2OH (3), which crystallizes in a 3D open framework with fourfold interpenetrated diamondoid network topology, represents the first 3D structure based on cpt anions. The structure differences demonstrate that the reaction metal ions have an important effect on the structures of these complexes.
Structure and Magnetic Properties of A μ‐Phenoxido‐bridged Dinuclear Cobalt(II) Complex
Authors: Lin Shuang‐Yan , Xu Gong‐Feng , Zhao Lang , Tang Jinkui , Liu Gui‐Xia
Published: December 2010

A new dinuclear cobalt(II) complex [Co2L2Cl2(CH3OH)2] (1), where HL = 3‐[(furan‐2‐ylmethylimino)methyl]‐2‐hydroxy‐5‐methylbenzaldehyde, derived from the in situ condensation of 2,6‐diformyl‐4‐methylphenol with furfurylamine, was prepared and structurally and magnetically characterized. Single crystal X‐ray structural determination reveals that the structure consists of centrosymmetric dinuclear units with each CoII ion in a slightly distorted octahedral environment. Lines’ model, which in principle can theoretically separate in spin‐only and orbital contribution, was used to fit the variable temperature susceptibility (2–300 K), suggesting an intramolecular antiferromagnetic interaction between the cobalt(II) ions.
Phenotypic responses of Spartina anglica to duration of tidal immersion
Authors: Li Hongli , Lei Guangchun , Zhi Yingbiao , Bridgewater Peter , Zhao Lei , Wang Yu , Deng Zifa , Liu Yuhong , Liu Fude , An Shuqing
Published: December 2010

Although Spartina anglica C.E. Hubbard continues to be invasive in many countries, this species has experienced a drastic decline in coastal China over the last decade. We hypothesize that changes in the duration of tidal immersion were responsible for this decline because the elevation of the S. anglica‐dominated area in coastal China has increased greatly over the last decade. We examined the effects of the duration of simulated tidal immersion and plant material provenance on growth, asexual reproduction, biomass accumulation, and allocation (percent of above‐ground biomass to total biomass) of S. anglica in a greenhouse experiment. The provenance of S. anglica did not significantly affect any traits measured except for height, stalk diameter, and leaf area. However, all traits were affected by the duration of immersion. Plants grown under 6 h of immersion were taller and had more leaves, more roots, and larger leaf area than those under 2, 4, 8, and 10 h of immersion. Asexual traits and biomass of the plants grown under 6 h of immersion were significantly larger than those under other immersion durations. The results suggested that S. anglica benefits from tidal immersion and decreasing duration of tidal immersion may have resulted in the decline of the S. anglica populations in coastal China. Thus, controlling the duration of tidal immersion may be an effective way of controlling invasiveness of this species elsewhere in the world.
Jatropha Diterpenes: a Review
Authors: Devappa Rakshit K. , Makkar Harinder P. S. , Becker Klaus
Published: December 2010

Terpenes are the largest group of phytochemicals that exhibit diverse functions in mediating antagonistic and beneficial interactions in, and among, organisms. For many years the abundance and distribution of terpenoid compounds in plants have benefitted both nature and human civilization. Jatropha species, belonging to the family Euphorbiaceae, are a rich source of terpenoid compounds. Among the terpenes, diterpenoid compounds have dominated the research area in Jatropha species with respect to their novel chemical structures and medicinal values. The present review describes the chemistry and biological activities of an array of Jatropha diterpenes. The diterpenes isolated from Jatropha species belongs to rhamnofolane, daphnane, lathyrane, tigliane, dinorditerpene, deoxy preussomerin and pimarane skeletal structures. Among the 68 diterpenes collated in this review, the biological activity of compounds varied distinctly—the majority of the diterpenes exhibited cytotoxic, antitumor and antimicrobial activities in vitro. To name a few, jatrophone, spruceanol and jatrophatrione exhibited antitumor properties against P338 lymphocytic leukemia and japodagrol against KB carcinoma cells. Whereas, curcusone B exhibited anti‐invasive effects against cholangiocarcinoma cells. The phorbol esters (Jatropha factor C1–C6) and Jatropherol exhibited insect deterrent/cytotoxic properties. Many diterpenes (jatrophalactam, faveline derivatives, multifolone, curcusone, jatrophone derivatives etc.) showed in‐vitro cytotoxic activity, while japodagrin, jatrogrossidione derivatives and jatropholone derivatives exhibited antimicrobial activities. Jatropha diterpenoids having a wide spectrum of bioactivity could form lead compounds or could be used as templates for the synthesis of new compounds with better biological activity for utilization in the pharmaceutical industries.
The Biodegradabilities of Different Oil‐Based Fatliquors
Authors: Luo Zhaoyang , Xia Chunchun , Fan Haojun , Chen Xin , Peng Biyu
Published: December 2010

The biodegradabilities of different oil‐based fatliquors derived from rape oil, fish oil, castor oil or mineral oil variants were investigated by evaluating the respiration curves, BOD5/COD values, COD (chemical oxygen demand) and TOC (total organic carbon) removal ratios. Simultaneously, degradation kinetics of the fatliquors were also studied. The results indicated that the BOD5/COD values and the COD and TOC removal ratios of all the natural oil based products are higher than 0.45 and 85%, respectively, implying that all of them are biodegradable. The mineral oil based fatliquors have lower than 0.2 and 10% values, showing unbiodegradable characteristics and were used as the control. The biodegradability order is castor oil > fish oil > rape oil > mineral oil product. Further study indicated that the differences in biodegradability result from the varying fatty acid composition (such as ricinoleic acid and polyunsaturated fatty acids). The higher the active group content, the more beneficial for modification reactions and result in a higher biodegradation rate. The degradation kinetics studies revealed that the degradation rate constants (k) of castor oil, fish oil and rape oil products are 0.87, 0.84 and 0.81 d−1 for the sulfated fatliquor, and 0.95, 0.93, 0.85 d−1 for the oxidized–sulfited fatliquors, respectively; indicating that the overall degradation rate followed the same trend as the biodegradability order where castor oil > fish oil > rape oil, whether the fatliquors underwent modification as sulfated or oxidized–sulfited.
Die Einschätzung des Gefährdungspotentials von Glücksspielen
Authors: Meyer Gerhard , Häfeli Jörg , Mörsen Chantal , Fiebig Marisa
Published: December 2010

Fragestellung: Die vorliegende Studie verfolgt das Ziel, basierend auf den Veranstaltungsmerkmalen von Glücksspielen Beurteilungsmerkmale zu generieren und empirisch zu validieren, die eine Einschätzung des Gefährdungspotentials der verschiedenen, in deutschsprachigen Ländern angebotenen Spielformen sowie neuer, geplanter Produkte ermöglichen. Methodik: In der ersten Stufe erfolgte im Rahmen einer Delphi-Studie die Befragung von 26 Experten, die zu einer Auswahl relevanter Merkmale und Merkmalsausprägungen führte. Die darauf aufbauende zweite Stufe der standardisierten Datenerhebung von Normalspielern sowie problematischen und pathologischen Spielern (Merkmale: N = 363; Ausprägungen: N = 356) diente der empirischen Validierung. Ergebnisse: Es wurden 10 Merkmale ermittelt, die mit unterschiedlichen Gewichten und differenzierten Merkmalsausprägungen in die Berechnung des Gefährdungspotentials eingehen. Die testtheoretische Überprüfung deutet darauf hin, dass es sich um ein zuverlässiges (Cronbachs α = 0.91; Inter-Item-Korrelation = 0.50; Item-Trennschärfe = 0.33–0.80) und valides Messinstrument handelt, wie Zusammenhangsmaße mit externen Kriterien wie Daten einer epidemiologischen Studie und aus der Versorgungsforschung belegen. Schlussfolgerungen: Ein derartiges, testtheoretisch abgesichertes Bewertungsinstrument kann zukünftig dem Gesetzgeber und der Rechtsprechung, den Glücksspielanbietern und Konsumenten als Grundlage bei der Risikoabschätzung von Glücksspielformen dienen.
Ecohydrological responses to multifactor global change in a tallgrass prairie: A modeling analysis
Authors: Bell Jesse Eugene , Weng Ensheng , Luo Yiqi
Published: December 2010

Relative impacts of multiple global change factors on ecohydrological processes in terrestrial ecosystems have not been carefully studied. In this study, we used a terrestrial ecosystem (TECO) model to examine effects of three global change factors (i.e., climate warming, elevated CO2, and altered precipitation) individually and in combination on runoff, evaporation, transpiration, rooting zone soil moisture content, water use efficiency (WUE), and rain use efficiency (RUE) in a North American tallgrass prairie. We conducted a total of 200 different scenarios with gradual changes of the three factors for 100 years. Our modeling results show strong responses of runoff, evaporation, transpiration, and rooting zone soil moisture to changes in temperature and precipitation, while effects of CO2 changes were relatively minor. For example, runoff decreased by 50% with a 10°C increase in temperature and increased by 250% with doubled precipitation. Ecosystem‐level RUE increased with CO2, decreased with precipitation, and optimized at 4–6°C of warming. In contrast, plant‐level WUE was highest at doubled CO2, doubled precipitation, and ambient temperature. The different response patterns of RUE and WUE signify that processes at different scales responded uniquely to climate change. Combinations of temperature, CO2, and precipitation anomalies interactively affected response magnitude and/or patterns of ecohydrological processes. Our results suggest that ecohydrological processes were considerably affected by global change factors and then likely regulate other ecosystem processes, such as carbon and nitrogen cycling. In particular, substantial changes in runoff to different climate change scenarios could have policy implications because it is a major component to replenishing freshwater. These modeling results should be tested by and could influence design of field experiments on ecohydrological processes.
Response of the Mediterranean and Dead Sea coastal aquifers to sea level variations
Authors: Yechieli Y. , Shalev E. , Wollman S. , Kiro Y. , Kafri U.
Published: December 2010

The present study examines the response of groundwater systems to expected changes in the Mediterranean Sea (rise of <1cm/yr) and Dead Sea levels (decline of ∼1 m/yr). A fast response is observed in the Dead Sea coastal aquifer, exhibited both in the drop of the water levels and in the location of the fresh‐saline water interface. No such effect is yet observed in the Mediterranean coastal aquifer, as expected. Numerical simulations, using the FeFlow software, show that the effect of global sea level rise depends on the coastal topography next to the shoreline. A slope of 2.5‰ is expected to yield a shift of the interface by 400 m, after a rise of 1m (∼100 years), whereas a vertical slope will yield no shift. Reduced recharge due to climate change or overexploitation of groundwater also enhances the inland shift of the interface.
Seagrass community metabolism: Assessing the carbon sink capacity of seagrass meadows
Authors: Duarte Carlos M. , Marbà Núria , Gacia Esperança , Fourqurean James W. , Beggins Jeff , Barrón Cristina , Apostolaki Eugenia T.
Published: December 2010

The metabolic rates of seagrass communities were synthesized on the basis of a data set on seagrass community metabolism containing 403 individual estimates derived from a total of 155 different sites. Gross primary production (GPP) rates (mean ± SE = 224.9 ± 11.1 mmol O2 m−2 d−1) tended to be significantly higher than the corresponding respiration (R) rates (mean ± SE = 187.6 ± 10.1 mmol O2 m−2 d−1), indicating that seagrass meadows tend to be autotrophic ecosystems, reflected in a positive mean net community production (NCP 27.2 ± 5.8 mmol O2 m−2 d−1) and a mean P/R ratio above 1 (1.55 ± 0.13). Tropical seagrass meadows tended to support higher metabolic rates and somewhat lower NCP than temperate ones. The P/R ratio tended to increase with increasing GPP, exceeding, on average, the value of 1 indicative of metabolic balance for communities supporting a GPP greater than 186 mmol O2 m−2 d−1, on average. The global NCP of seagrass meadows ranged (95% confidence limits of mean values) from 20.73 to 50.69 Tg C yr−1 considering a low global seagrass area of 300,000 km2 and 41.47 to 101.39 Tg C yr−1 when a high estimate of global seagrass area of 600,000 km2 was considered. The global loss of 29% of the seagrass area represents, therefore, a major loss of intense natural carbon sinks in the biosphere.
Potential climate impact of black carbon emitted by rockets
Authors: Ross Martin , Mills Michael , Toohey Darin
Published: December 2010

A new type of hydrocarbon rocket engine is expected to power a fleet of suborbital rockets for commercial and scientific purposes in coming decades. A global climate model predicts that emissions from a fleet of 1000 launches per year of suborbital rockets would create a persistent layer of black carbon particles in the northern stratosphere that could cause potentially significant changes in the global atmospheric circulation and distributions of ozone and temperature. Tropical stratospheric ozone abundances are predicted to change as much as 1%, while polar ozone changes by up to 6%. Polar surface temperatures change as much as one degree K regionally with significant impacts on polar sea ice fractions. After one decade of continuous launches, globally averaged radiative forcing from the black carbon would exceed the forcing from the emitted CO2 by a factor of about 105 and would be comparable to the radiative forcing estimated from current subsonic aviation.
Strong vertical mixing of deep water of a stratified reservoir during the Maule earthquake, central Chile (Mw 8.8)
Authors: de la Fuente Alberto , Meruane Carolina , Contreras Manuel , Ulloa Hugo , Niño Yarko
Published: December 2010

Vertical profiles of water temperature in Rapel reservoir (central Chile, 34° 2′ 23″ S, 71° 35′ 23″ W, 110 m.a.s.l.), recorded the hydrodynamic response of the stratified water column of the reservoir produced by the 8.8 magnitude Maule earthquake (epicentre located in 36°15′36″S, 73°14′ 20″W), showing an intense vertical mixing of deep water. The vertical mixing was characterized by changes in the potential energy of the water column and the eddy diffusivity of the mixing, and these values were used to estimate the mixing efficiency of the event. It is hypothesized that the turbulent flow that mixed the water column was mainly induced by the oscillation of the bed, although surface gravitational waves could also have contributed to the vertical mixing. So far, this is the first time that the hydrodynamic response of a reservoir during a mega‐earthquake is measured and described.
Statistical study of O+ transport from the cusp to the lobes with Cluster CODIF data
Authors: Liao J. , Kistler L. M. , Mouikis C. G. , Klecker B. , Dandouras I. , Zhang J.‐C.
Published: December 2010

Ionospheric origin O+ accelerated in the cusp/cleft region convects over the polar cap and flows along open field lines to the tail lobes. Some O+ in the lobes enters the near‐Earth plasma sheet where it is then convected to the inner magnetosphere, while some O+ ends up in the distant tail where it is lost. In order to understand the transport of ionospheric O+ to the plasma sheet so as to understand its contribution to the formation of geomagnetic storms, we have determined the occurrence frequency of cusp source O+ over the polar caps and in the lobes to determine where and when it is observed. The results show that the probability of observing O+ along the transport path is high even during nonstorm times, although, as expected, the highest probability is found during storm times. It was also found that when interplanetary magnetic field (IMF) By is positive, O+ from the northern cusp/cleft tends to stream toward the dawnside tail lobe while O+ from the south are observed on the duskside. The transport path for negative IMF By is more symmetric, but shows some evidence for a reversed asymmetry when IMF By is strongly negative. IMF Bz has little influence on the asymmetry. The asymmetry for positive By and lack of mirror symmetry between positive and negative By most likely result from the combination of convection driven by the solar wind and coupling with the ionosphere. Similar asymmetries have been observed in the convection patterns over the polar caps, which are attributed to a day‐night ionospheric conductivity gradient adding to the IMF By effect. However, there are some disagreements between the asymmetries observed in polar cap potential patterns and the asymmetries observed in the O+ spatial distribution, indicating there may be other causes for the symmetry breaking, in addition to the day‐night conductivity gradient.
Subsidence pattern in the central Adriatic and its influence on sediment architecture during the last 400 kyr
Authors: Maselli V. , Trincardi F. , Cattaneo A. , Ridente D. , Asioli A.
Published: December 2010

The western Adriatic margin (eastern Mediterranean), part of the Apennine foreland, is characterized by a differentiated tectonic setting, showing high subsidence rates (up to 1 mm/yr) in the northern area and tectonic uplift (on the order of 0.3–0.5 mm/yr) in the southern part corresponding with the so‐called Apulia swell. The central Adriatic marks the transition between these two areas. To calculate subsidence values, the stratigraphy of the central Adriatic has been investigated through the borehole PRAD1.2 (European project Profiles across Mediterranean Sedimentary Systems), the first continuous Quaternary marine record in the Adriatic basin (71.2 m long) reaching the top of Marine Isotope Stage 11 (MIS 11). Subsidence calculations were performed first by applying the backstripping procedure to PRAD1.2, in order to investigate the contribution of sediment load and tectonic driving forces to subsidence. Despite the large error bars, mostly caused by the uncertainties in paleowater depth reconstructions, the values obtained demonstrate that tectonics is the main driver for subsidence in this area. In order to better estimate the subsidence rates, an independent approach is introduced, based on the correlation of the present‐day burial depth of past shorelines deposited during the main glacial lowstands, from MIS 2 to MIS 10. The average subsidence rate of about 0.3 mm/yr appears greater than the average sediment supply rate (0.15 mm/yr), and this fact explains the overall backstepping of the 100 kyr regressive depositional sequences on the margin. The results obtained help to improve the understanding of the regional tectonics and can be used for quantitative reconstruction of Quaternary sea level changes in the Adriatic region. In general, the paper shows that even a short (71 m) borehole across a relatively short time span (340 kyr) can be useful for subsidence calculations, provided that a high‐resolution definition of its stratigraphy is available and a correlation can be drawn with the geomorphologic proxies such as paleoshoreline deposits.
A model of the three‐dimensional evolution of Arctic melt ponds on first‐year and multiyear sea ice
Authors: Scott F. , Feltham D. L.
Published: December 2010

During winter the ocean surface in polar regions freezes over to form sea ice. In the summer the upper layers of sea ice and snow melts producing meltwater that accumulates in Arctic melt ponds on the surface of sea ice. An accurate estimate of the fraction of the sea ice surface covered in melt ponds is essential for a realistic estimate of the albedo for global climate models. We present a melt‐pond–sea‐ice model that simulates the three‐dimensional evolution of melt ponds on an Arctic sea ice surface. The advancements of this model compared to previous models are the inclusion of snow topography; meltwater transport rates are calculated from hydraulic gradients and ice permeability; and the incorporation of a detailed one‐dimensional, thermodynamic radiative balance. Results of model runs simulating first‐year and multiyear sea ice are presented. Model results show good agreement with observations, with duration of pond coverage, pond area, and ice ablation comparing well for both the first‐year ice and multiyear ice cases. We investigate the sensitivity of the melt pond cover to changes in ice topography, snow topography, and vertical ice permeability. Snow was found to have an important impact mainly at the start of the melt season, whereas initial ice topography strongly controlled pond size and pond fraction throughout the melt season. A reduction in ice permeability allowed surface flooding of relatively flat, first‐year ice but had little impact on the pond coverage of rougher, multiyear ice. We discuss our results, including model shortcomings and areas of experimental uncertainty.
Interannual variability of Arctic sea ice export into the East Greenland Current
Authors: Cox K. A. , Stanford J. D. , McVicar A. J. , Rohling E. J. , Heywood K. J. , Bacon S. , Bolshaw M. , Dodd P. A. , De la Rosa S. , Wilkinson D.
Published: December 2010

Observations since the 1950s suggest that the Arctic climate system is changing in response to rising global air temperatures. These changes include an intensified hydrological cycle, Arctic sea ice decline, and increasing Greenland glacial melt. Here we use new δ18O data from the East Greenland Current system at Cape Farewell and Denmark Strait to determine the relative proportions of the freshwater components within the East Greenland Current and East Greenland Coastal Current. Through the comparison of these new data with historical studies, we gain insight into the changing Arctic freshwater balance. We detect three key shifts in the net freshwater component δ18O values, these are (1) a shift to lighter values in the late 1990s that possibly indicates an increased Greenland glacial melt or a reduced sea ice melt admixture and (2) a short‐term shift to a ∼10‰ heavier value in 2005 followed by (3) a shift back to the historic average value in 2008. The latter fluctuation reflects a short‐term dramatic rise and fall of sea ice meltwater addition into the East Greenland Current system. We infer that this anomalously large inclusion of sea ice meltwater resulted from a short‐term peak in Arctic sea ice export via Fram Strait. Our findings, therefore, suggest that the freshwater carried in the East Greenland Current system is susceptible to short‐term, high‐amplitude changes in the upstream freshwater balance, which may have important ramifications for the global thermohaline circulation through the suppression of deep water formation in the North Atlantic.
Wave setup over a Pacific Island fringing reef
Authors: Vetter O. , Becker J. M. , Merrifield M. A. , Pequignet A.‐C. , Aucan J. , Boc S. J. , Pollock C. E.
Published: December 2010

Measurements obtained across a shore‐attached, fringing reef on the southeast coast of the island of Guam are examined to determine the relationship between incident waves and wave‐driven setup during storm and nonstorm conditions. Wave setup on the reef flat correlates well (r > 0.95) and scales near the shore as approximately 35% of the incident root mean square wave height in 8 m water depth. Waves generated by tropical storm Man‐Yi result in a 1.3 m setup during the peak of the storm. Predictions based on traditional setup theory (steady state, inviscid cross‐shore momentum and depth‐limited wave breaking) and an idealized model of localized wave breaking at the fore reef are in agreement with the observations. The reef flat setup is used to estimate a similarity parameter at breaking that is in agreement with observations from a steeply sloping sandy beach. A weak (∼10%) increase in setup is observed across the reef flat during wave events. The inclusion of bottom stress in the cross‐shore momentum balance may account for a portion of this signal, but this assessment is inconclusive as the reef flat currents in some cases are in the wrong direction to account for the increase. An independent check of fringing reef setup dynamics is carried out for measurements at the neighboring island of Saipan with good agreement.
Production velocity of sea spray droplets
Authors: Andreas Edgar L , Jones Kathleen F. , Fairall Christopher W.
Published: December 2010

The sea spray generation function dF/dr0 predicts the rate at which droplets of initial radius r0 are produced at the sea surface. Because this function is not readily measurable in the marine environment, however, it is often inferred from measurements of the near‐surface droplet concentration, C(r0), through an assumed velocity scale, the effective spray production velocity. This paper proceeds in reverse, though: It uses a reliable estimate of dF/dr0 and 13 sets of measurements of C(r0) over the ocean to calculate the implied effective production velocity, Veff, for droplets with initial radii r0 from 5 to 300 μm. It then compares these Veff values with four candidate expressions for this production velocity: the dry‐deposition velocity, VDh; the mean wind speed at the significant wave amplitude (A1/3), the standard deviation in vertical droplet velocity, σwd; and laboratory measurements of the ejection velocity of jet droplets, Vej. The velocity scales and Vej agree best with the implied Veff values for 20 ≤ r0 ≤ 300 μm. The deposition velocity, VDh, which is the velocity most commonly used in this application, agrees worst with the Veff values. For droplets with r0 less than about 20 μm, the analysis also rejects the main hypothesis: that dF/dr0 and C(r0) can be related through a velocity scale. These smaller droplets simply have residence times that are too long for spray concentrations to be in local equilibrium with the spray production rate.
Evaluation of snow cover and depth simulated by a land surface model using detailed regional snow observations from Austria
Authors: Parajka Juraj , Dadson Simon , Lafon Thomas , Essery Richard
Published: December 2010

An evaluation is undertaken of the accuracy with which the Joint UK Land Environment Simulator (JULES) can simulate snow cover and depth when driven using data from the Hadley Centre regional climate model. The JULES model provides the facility to diagnose the thermal and hydrological state of the land surface and soil given time‐varying inputs of air temperature, wind speed, humidity, shortwave and longwave radiation, and precipitation. The observed data set used in this study consists of daily snow depths measurements at 601 climate stations with more than 15 years of observations in the period from January 1976 to December 2000. In this study, the JULES model was driven using two data sets at 25 km horizontal resolution: one produced using the U. K. Met Office Hadley Centre regional climate model HadRM3‐P (RCM), the other in which regional climate model precipitation and air temperature data were replaced with observed values (RCM+PT). The results indicate good agreement between the land surface model simulations and observations of snow cover at climate stations. The median snow cover accuracy indices for all 601 stations were 89% and 91% for the RCM and the combined RCM+PT driving data sets, respectively, with only a small interannual variation. In contrast, the differences between modeled and measured snow depth were much larger. The median values of mean snow depth bias were similar, −0.4 cm for RCM and −1.2 cm for RCM+PT; however, the RCM simulation was found to overestimate the observed snow depth at more than 25% of climate stations. The extent to which the results from RCM‐driven simulations match observed data is strongly related to the accuracy of the RCM precipitation. The large overestimation has significant impact on the snow mass simulation and the assessment of extreme values in the mountains. We note that even if snow cover can be simulated with a high degree of accuracy, this should not imply a similarly high degree of accuracy in the simulation of snow depth. Model performance was poorest in regions of significant topographic heterogeneity and our findings suggest that the most promising additional model developments should be directed toward computationally efficient representations of subgrid topography.