bluuebunny/crossref_metadata_2025 huggingface dataset:
Point Defect Clusters Induced by High-Speed Deformation and its Effect on Age-Hardening in 6061 Aluminum Alloys
Authors: Horikawa Keitaro , Kitani Yuki , Ogura Tomo , Hirose Akio , Takahashi Makoto , Kobayashi Hidetoshi
Published: June 2014

Effects of high-speed deformation on age hardening and microstructural evolution behavior of 6061 aluminum alloys were studied. By affecting the high-speed impact compression (about 5 GPa) to the 6061 aluminum alloy plate in the state of quenching after the solution heat treatment, the maximum hardness became twice as high as the original hardness. Even after the impact compression, age-hardening was clearly identified both at 175 °C and 100 °C. TEM observation revealed that point defect clusters were distributed densely inside grains after the impact compression, possibly due to the effect of high-speed deformation. The point defect clusters observed were assumed to be stacking fault tetrahedra on the basis of high resolution TEM analysis. The point defect clusters and precipitates were both visible even after the peak-aged condition at 175 °C. The 6061 aluminum alloy specimen after the solution heat treatment, followed by the impact compression (8.0 GPa) and the peak-aged condition showed the highest hardness value (154 Hv) among the testing conditions selected in the present study.
Upgrading Property of A-Fe Alloys through the Microstructure Refinement by Compressive Torsion Processing
Authors: Kume Yuji , Ota Shinichiro , Kobashi Makoto , Kanetake Naoyuki
Published: June 2014

Cast AlFe alloys containing several percent iron have low ductility because of their brittle precipitates. Therefore, precipitate refinement is very important for improving their mechanical properties. In recent decades, severe plastic deformation processes have been developed to achieve this grain refinement. For example, our previously proposed severe plastic deformation process, called compressive torsion, is quite effective for not only grain refinement but also precipitate refinement even in brittle materials. In the present work, precipitate refinement of cast Al—Fe alloys by compressive torsion and the resulting improvements in their tensile properties were investigated. Compressive torsion with various numbers of revolutions was applied to Al—Fe alloys at 373 K. Then, the alloys were subjected to tensile testing at room temperature, 473 K, and 573 K. The obtained experimental results indicated that the initial eutectic microstructure of the alloys disappeared after the compressive torsion processing. All large precipitates with sizes of more than 200 μm were refined, and their sizes were reduced to several tens of micrometers. Furthermore, these refined precipitates were dispersed homogenously in the alloy microstructure. In result, the tensile properties of the alloys, namely, their strength and elongation, were improved remarkably. In particular, the elongation reached more than 30% at room temperature.
TEM Observation of HPT-Processed Cu-Added Excess Mg-Type Al-Mg-Si Alloys
Authors: Maruno Shun , Watanabe Katsumi , Matsuda Kenji , Saikawa Seiji , Shoichi Hirosawa , Horita Zen Ji , Lee Seungwon , Terada Daisuke
Published: June 2014

Severe plastic deformation (SPD) techniques, such as equal channel angular pressing (ECAP), accumulative roll bonding (ARB) and high pressure torsion (HPT) have been extensively investigated to achieve. SPD techniques make use of plastic deformation process where no change in the cross-sectional dimension of a work piece occurs during straining. In this work, the effect of HPT on the aging behavior and microstructure in excess Mg-type Al-Mg-Si alloys including Cu are investigated. These alloys were investigated by hardness test and transmission electron microscopy (TEM) observation.The results show that processing by HPT leads to significant grain refinement with a grain size of 200-250nm.An age-hardening phenomenon is observed at 343K and 373K for the Al-Mg-Si alloys with HPT. Some precipitates were observed on grain boundaries.
Heat Treatment of Aluminum-Titanium-Compounds Made by Co-Extrusion and Friction Welding
Authors: Striewe Barbara , von Hehl Axel , Grittner Norbert , Schaper Mirko , Nürnberger Florian
Published: June 2014

The combination of aluminum and titanium alloys allows for designing lightweight structures with tailor-made properties at the macroscopic global as well as at the microscopic scale. In this context both co-extrusion and friction welding offer a great potential for advanced solutions for products with material combinations of aluminum and titanium. While titanium alloys show particular high mechanical strength and good corrosion resistance, aluminum alloys provide a considerable high specific bending stiffness along with low materials costs. Since the mechanical properties of metallic composites highly depend on the existence and formation of the intermetallic layer in the bonding zone compounds were processed by co-extrusion and friction welding and subsequent heat treatment to investigate the strength and the composition of the bonding zone. The results of friction welded samples concerning the intermetallic layer that was formed during heat treatment were compared with those directly after the co-extrusion. In this layer an enrichment of elements which origin from the aluminum alloy, particularly silicon, was observed. The layer was characterized by optical microscopy, scanning electron microscopy as well as electron probe micro analysis. The mechanical properties were determined by tensile tests.
Effect of Liquid Hot Isostatic Pressing on Structure and Mechanical Properties of an Aluminum Alloy
Authors: Tagirov Damir , Kulitskiy Vladislav , Belov Nikolay , Kaibyshev Rustam
Published: June 2014

The effect of liquid hot isostatic pressing (LHIP) on microstructure and mechanical properties of a high-strength cast Al-6Zn-2Mg-0.5Fe-0.7Ni alloy was examined. LHIP eliminates shrinkage porosity that highly improves strength and fatigue limit. Yield stress (YS) and ultimate tensile strength (UTS) in T6 condition increased from 135 to 470 MPa and from 410 to 510 MPa, respectively. Endurance limit on the base of 107 cycles increased from 95 to 140 MPa. However, a small number of gas pores with an average size less than 2 μm retains. LHIP suppresses the crack initiation on coarse cavities. However, brittle intergranular fracture occurs in the hipped alloy through the breaking of eutectic phase Al9FeNi. As a result, elongation-to-failure was of 1.2% and the fatigue strength is equal to one of AA356.02 alloy subjected to LHIP.
Improvement of Mechanical Properties by Two-Step Aging in Ultrafine Grained Al-Ag-Sc Alloy
Authors: Terada Daisuke , Zeng Yan , Tsuji Nobuhiro
Published: June 2014

In order to improve limited ductility of ultrafine grained (UFG) Al alloys, mechanical properties of an UFG Al alloy having fine precipitates within grains were investigated. An Al-0.2wt%Sc-4.2wt%Ag alloy was severely deformed by the ARB process at room temperature and subsequently heat-treated by a two-step aging. After the first aging in the two-step aging, fine Al3Sc precipitates were formed. In the specimen ARB processed by 4cycles, the fine Al3Sc precipitates were homogeneously dispersed within the grains. On the other hand, in the specimen ARB processed by 8 cycles, Al3Sc precipitates were linearly-aligned on the grain boundaries that had moved during the heat treatment. After the second aging, fine G.P. zones of Ag as well as Ag2Al precipitates were observed within the grains in the specimen ARB processed by 4 cycles. Coarse precipitates of Ag2Al at grain boundaries were observed in the specimen ARB processed by 8 cycles. The difference in the distribution of precipitates was considered to be due to the difference in fraction of high angle grain boundaries in the matrix microstructures. The strength of the solution treated specimen increased by the two-step aging while the tensile elongation decreased. On the other hand, both of the strength and elongation of the specimen ARB processed by 4 cycles increased after the two-step aging. In case of the specimen ARB processed by 8 cycles, the strength decreased slightly and the elongation increased by the two-step aging, and the aged specimen exhibited a good balance between strength and elongation.
Influence of PVD Target Power on the Age Hardening Behaviour of Al-4Zr Micro Sheets
Authors: von Bargen Roland , Kovac Julien , von Hehl Axel , Mehner Andreas , Zoch Hans Werner
Published: June 2014

High strength aluminium alloys with improved stability at elevated temperatures for micro components, which are needed e.g. in the automotive or the micro electronics industry, require new alloys and advanced production processes regarding primary shaping, heat treatment and cold forming. Their development is part of the Collaborative Research Centre 747 Micro Cold Forming of the German Research Foundation. Especially heat treatment is a necessary step in the manufacturing process chain to adjust the mechanical properties of semi-finished micro components to cold forming and finally the usage properties of aluminium micro components by precipitation hardening to increase the strength above the strain hardened level. Conventional casting techniques limit the dissolvable zirconium content in alloys to 0.28 mass-% due to Al3Zr precipitation of higher contents during slow cooling. With physical vapour deposition (PVD) by magnetron sputtering at temperatures below 50 °C it is possible to achieve alloys with a highly oversaturated solid solution and up to 3.6 mass-% of zirconium. The target power of the plasma during the magnetron sputtering process has considerable impact on the mechanical properties of the deposited Al-Zr alloys. Therefore the age hardening response of different micro sheets is evaluated by ultra micro hardness measurements (UMH), transmission electron microscopy (TEM) and differential power scanning calorimetry (DPSC).
Complementarity of Atom Probe, Small Angle Scattering and Differential Scanning Calorimetry for the Study of Precipitation in Aluminium Alloys
Authors: de Geuser Frédéric , Dorin Thomas , Lefebvre Williams , Gault Baptiste , Deschamps Alexis
Published: June 2014

Two examples of precipitation studies (in Al-Li-Cu and Al-Li-Mg alloys) are shown to demonstrate the complementarity of atom probe tomography, small-angle-scattering and differential scanning calorimetry for precipitation studies. It will be used to unravel an unexpected two-step precipitation behavior of T1 in Al-Li-Cu and to ascertain precipitates size in Al-Li-Mg. through a model free comparison between atom probe and SAXS.
Tensile Properties and Hot-Tearing Tendencies of 3xxx Alloys
Authors: Nordmark Arne , Ellingsen Kjerstin , Johansson Anders U. , M'Hamdi Mohammed , Kvithyld Anne , Marson Andrew , Azar Amin
Published: June 2014

A set-up for tensile testing in the mushy zone allowing for studies of semi-solid mechanical behavior is available at SINTEF. A hot-tearing experimental set-up has recently been developed allowing for investigation of the hot-tearing susceptibility of industrial aluminium alloys and effects of e.g. alloying composition and grain-refiner. Load and temperature are registered during constrained solidification giving information on the mechanical behavior of the alloy during solidification. Two crack-prone alloys in the 3xxx-series (A and B) have been investigated using both techniques and the results analyzed using information about solidification path from a thermo-physical model. Alloy B is found to be mechanically weaker in the interval most susceptible to hot-tearing in agreement with cast-house experience. This study shows that the experimental techniques combined with thermo-physical modeling and characterization allow for a better understanding of the hot-tearing sensitivity of the alloys.
The Life-Time of Structural Vacancies in the Presence of Solute Trapping
Authors: Lang Peter , Shan Yao V. , Kozeschnik Ernst
Published: June 2014

Vacancies are the simplest type of lattice defect. However, they play a major role in the kinetics of diffusional processes, such as solid-state precipitation, where mass transport is directly proportional to the concentration of vacancies. We present a physical modelling framework, where we simulate the evolution of excess vacancies on the example of Al-alloys during simplified time-temperature treatments. Interaction energies between solute atoms and vacancies are evaluated by first-principle analysis. Assuming that the escape of vacancies from existing traps is dependent on temperature and binding energies, we explore the life-time of non-equilibrium vacancies and the natural and artificial aging response of Al alloys. The predictions of the model are finally compared to experimental data.
TEM Observation of Precipitates in Excess Mg-Type Al-Mg-Si Alloys Aged at 473K after Deformation
Authors: Ogawa Yurie , Ikeno Susumu , Yoshimura Yasuharu , Kita Kazuhiko , Matsuda Kenji
Published: June 2014

It has been known that transition metals improve the mechanical property of Al-Mg-Si alloy. The thermo-mechanical treatment is also effective to improve the strength of Al-Mg-Si alloy. In this work, the aging behavior of deformed excess Mg-type Al-Mg-Si alloy including Ag and Cu was investigated by hardness test and TEM observation. The needle-shaped precipitates were aligned in the <001> directions of the matrix in Cu addition alloy at 473K for 3.84ks. The contrast of dislocation was observed in 10% rolled specimens, which increased with amount of deformation. The precipitates were observed on dislocations but not in the matrix for 0.24ks. The precipitates were observed in the matrix with increasing aging time.
Report on the 42nd International Symposium: Actual Tasks on Agricultural Engineering, 25-28 February 2014, Opatija, Croatia
Authors: Kosutic Silvio , De Wrachien Daniele
Published: June 2014

The 42nd International Symposium Actual Tasks on Agricultural Engineering was held on 25th-28th February 2014 in Grand Hotel Adriatic Opatija, Republic of Croatia. The principal Organiser - the Agricultural Engineering Department, Faculty of Agriculture, University of Zagreb - was supported by the following frameworks: Department of Agricultural Engineering, Faculty of Agriculture, University J.J. Strossmayer, Osijek, Department of Bio-systems Engineering, Faculty of Agriculture, University of Maribor (Slovenia), Agricultural Institute of Slovenia, Hungarian Institute of Agricultural Engineering Gödöllö and Croatian Agricultural Engineering Society. In addition, CIGR, EurAgEng, AAAE bestowed their support and endorsement on the Event.
Body imaging: Diagnosis
Authors: Misser Shalendra K. , Steer Dion B. , Purcell Stephen
Published: June 2014

No abstract.
On the link between Amazonian forest properties and shallow cumulus cloud fields
Authors: Heiblum R. H. , Koren I. , Feingold G.
Published: June 2014

Abstract. During the dry season the Amazon forest is frequently covered by shallow cumulus clouds fields, referred to here as forest cumulus (FCu). These clouds are shown to be sensitive to land cover and exhibit a high level of spatial organization. In this study we use satellite data to perform a morphological classification and examine the link between FCu cloud field occurrence and the enhanced vegetation index (EVI), which is commonly used as a measure for forest density and productivity. Although weaker than first-order effects of meteorology, a clear positive linear relation between EVI (i.e., surface properties) and FCu field occurrence is seen over forest land cover, implying a strong coupling between forest surface fluxes and the cloud organization above. Over non-forest land cover the relationship between EVI and FCu occurrence is nonlinear, showing a reduction of FCu for high EVI values. We find that forest to non-forest transition zones display a superposition of the two different land cover dependencies.
Stratospheric winds: longitudinal distribution and long-term trends
Authors: Kozubek M. , Krizan P. , Lastovicka J.
Published: June 2014

Abstract. The wind is very important parameter of the stratospheric dynamics which can be affected by many factors like tropospheric North Atlantic Oscillation (NAO) or El Nino Southern Oscillation (ENSO), stratospheric Quasi-biennial Oscillation (QBO) or Sudden Stratospheric Warming (SSW) and solar activity. Due to lack of direct observations we have to use reanalysis data, here NCEP/NCAR reanalysis. The behaviour and trends of wind and its meridional component is analysed in this paper. The influence of NAO on trend in wind is significant in the lower stratosphere (100 hPa) in Atlantic sector; the trend is also affected by QBO, whereas influence of SSW is rather minor and observable only in the middle stratosphere (10 hPa). The most interesting result seems to be the longitudinal distribution of the meridional wind component. We identify two-core structure of strong but opposite winds, one at each hemisphere at 10 hPa, and a four-core structure at 100 hPa. These structures are not associated with tides. However, they appear to be related to the well-pronounced Aleutian pressure high at the 10 hPa level.
Atmospheric amines and ammonia measured with a Chemical Ionization Mass Spectrometer (CIMS)
Authors: You Y. , Kanawade V. P. , de Gouw J. A. , Guenther A. B. , Madronich S. , Sierra-Hernández M. R. , Lawler M. , Smith J. N. , Takahama S. , Ruggeri G. , Koss A. , Olson K. , Baumann K. , Weber R. J. , Nenes A. , Guo H. , Edgerton E. S. , Porcelli L. , Brune W. H. , Goldstein A. H. , Lee S.-H.
Published: June 2014

Abstract. We report ambient measurements of amines and ammonia with a~fast response chemical ionization mass spectrometer (CIMS) in a southeastern US forest in Alabama and a~moderately polluted Midwestern site during the summer. In the Alabama forest, mostly C3-amines (from pptv to tens of pptv) and ammonia (up to 2 ppbv) were detected on a daily basis. C3-amines and ammonia showed similar diurnal trends and temperature and wind direction dependences, and were not associated with transported CO and SO2 plumes. Consistent with temperature dependences, amine and ammonia in the gas and aerosol phases showed opposite diurnal trends, indicating gas-to-particle partitioning of amines and ammonia. Temperature dependences also imply reversible processes of amines and ammonia evaporation from soil surfaces in daytime and deposition of amines and ammonia to soil surfaces at nighttime. Various amines (C1–C6) at the pptv level were observed in the transported biomass burning plumes, showing that biomass burning can be a substantial source of amines in the Southeast US. At the moderately polluted Kent site, higher concentrations of amines (C1–C6, from pptv to tens of pptv) and ammonia (up to 6 ppbv) were detected. Diurnal variations of C1- to C3-amines and ammonia were correlated with the ambient temperature. C4- to C6-amines showed abrupt increases during the nighttime, suggesting that they were emitted from local sources. These abundant amines and ammonia may in part explain the frequent new particle formation events reported from Kent. Lower amine concentrations at the rural forested site highlight the importance of constraining anthropogenic sources of amines.
Competition between water uptake and ice nucleation by glassy organic aerosol particles
Authors: Berkemeier T. , Shiraiwa M. , Pöschl U. , Koop T.
Published: June 2014

Abstract. Organic aerosol particles play a key role in climate by serving as nuclei for clouds and precipitation. Their sources and composition are highly variable, and their phase state ranges from liquid to solid under atmospheric conditions, affecting the pathway of activation to cloud droplets and ice crystals. Due to slow diffusion of water in the particle phase, organic particles may deviate in phase and morphology from their thermodynamic equilibrium state, hampering the prediction of their influence on cloud formation. We overcome this problem by combining a novel semi-empirical method for estimation of water diffusivity with a kinetic flux model that explicitly treats water diffusion. We estimate timescales for particle deliquescence as well as various ice nucleation pathways for a wide variety of organic substances, including secondary organic aerosol (SOA) from the oxidation of isoprene, α-pinene, naphthalene, and dodecane. The simulations show that in typical atmospheric updrafts, glassy states and solid/liquid core-shell morphologies can persist for long enough that heterogeneous ice nucleation in the deposition and immersion mode can dominate over homogeneous ice nucleation. Such competition depends strongly on ambient temperature and relative humidity as well as humidification rates and particle sizes. Due to relatively high glass transition temperature and low hygroscopicity, naphthalene SOA particles have a higher potential to act as heterogeneous ice nuclei than the other investigated substances. Our findings demonstrate that kinetic limitations of water diffusion into organic aerosol particles strongly affect their ice nucleation pathways and require advanced formalisms for the description of ice cloud formation in atmospheric models.
Measurements of hydrogen sulfide (H2S) using PTR-MS: calibration, humidity dependence, inter-comparison and results from field studies in an oil and gas production region
Authors: Li R. , Warneke C. , Graus M. , Field R. , Geiger F. , Veres P. R. , Soltis J. , Li S.-M. , Murphy S. M. , Sweeney C. , Pétron G. , Roberts J. M. , de Gouw J.
Published: June 2014

Abstract. Natural gas production is associated with emissions of several trace gases, some of them classified as air toxics. While volatile organic compounds (VOCs) have received much attention, hydrogen sulfide (H2S) can also be of concern due to the known health impacts of exposure to this hazardous air pollutant. Here, we present quantitative, fast time-response measurements of H2S using Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS) instruments. An Ultra-Light-Weight PTR-MS (ULW-PTR-MS) in a mobile laboratory was operated for measurements of VOCs and H2S in a gas and oil field during the Uintah Basin Winter Ozone Study (UBWOS) 2012 campaign. Measurements of VOCs and H2S by a PTR-MS were also made at the Horse Pool ground site in the Uintah Basin during UBWOS 2013. The H2S measurement by PTR-MS is strongly humidity dependent because the proton affinity of H2S is only slightly higher than that of water. The H2S sensitivity of PTR-MS ranged between 0.6–1.4 ncps ppbv−1 (normalized counts per second/parts per billion by volume) during UBWOS 2013. We compare the humidity dependence determined in the laboratory with in-field calibrations and determine the H2S mixing ratios for the mobile and ground measurements. The PTR-MS measurements at Horse Pool are evaluated by comparison with simultaneous H2S measurements using a PTR Time-of-Flight MS (PTR-ToF-MS) and a Picarro cavity ring down spectroscopy (CRDS) instrument for H2S/CH4. On average 0.6 ± 0.3 ppbv H2S was present at Horse Pool during UBWOS 2013. The correlation between H2S and methane enhancements suggests that the source of H2S is associated with oil and gas extraction in the basin. Significant H2S mixing ratios of up to 9 ppmv downwind of storage tanks were observed during the mobile measurements. This study suggests that H2S emissions associated with oil and gas production can lead to short-term high levels close to point sources, and elevated background levels away from those sources. In addition, our work has demonstrated that PTR-MS can make reliable measurements of H2S at levels below 1 ppbv.
Composition changes of eroded carbon at different spatial scales in a tropical watershed suggest enrichment of degraded material during transport
Authors: Rumpel C. , Chaplot V. , Ciais P. , Chabbi A. , Bouahom B. , Valentin C.
Published: June 2014

Abstract. In order to assess whether eroded carbon is a net source or sink of atmospheric CO2, characterisation of the chemical composition and residence time of eroded organic matter (EOM) at the landscape level is needed. This information is crucial to evaluate (1) how fast EOM can be decomposed by soil microbes during its lateral transport and (2) its impact at deposition sites. This study considers a continuum of scales to measure the composition of EOM across a steep hillslope landscape of the Mekong basin with intense erosion. We sampled suspended sediments eroded during rainfall events from runoff plots (1 and 2.5 m2) and the outlets of four nested watersheds (0.6 × 104 to 1 × 107 m2). Here we show that changes in the chemical composition of EOM (measured by nuclear magnetic resonance spectroscopy) and in its 13C and 15N isotope composition from plot scale through to landscape scale provide consistent evidence for enrichment of more decomposed EOM across distances of 10 km. Between individual soil units (1 m2) to a small watershed (107 m2), the observed 28% decrease of the C/N ratio, the enrichment of 13C and 15N isotopes as well as O-alkyl C in EOM is of similar magnitude as changes recorded with depth in soil profiles due to soil organic matter "vertical" decomposition. Radiocarbon measurements indicated ageing of EOM from the plot to the watershed scale. Therefore transport of EOM may lead to enrichment of stabilised soil organic matter compounds, eventually being subject to export from the watershed.
A virtual water network of the Roman world
Authors: Dermody B. J. , van Beek R. P. H. , Meeks E. , Klein Goldewijk K. , Scheidel W. , van der Velde Y. , Bierkens M. F. P. , Wassen M. J. , Dekker S. C.
Published: June 2014

Abstract. The Romans were perhaps the most impressive exponents of water resource management in preindustrial times with irrigation and virtual water trade facilitating unprecedented urbanisation and socioeconomic stability for hundreds of years in a region of highly variable climate. To understand Roman water resource management in response to urbanisation and climate variability, a Virtual Water Network of the Roman World was developed. Using this network we find that irrigation and virtual water trade increased Roman resilience to climate variability in the short term. However, urbanisation arising from virtual water trade likely pushed the Empire closer to the boundary of its water resources, led to an increase in import costs, and reduced its resilience to climate variability in the long-term. In addition to improving our understanding of Roman water resource management, our cost-distance based analysis illuminates how increases in import costs arising from climatic and population pressures are likely to be distributed in the future global virtual water network.
Modelling survival and connectivity of Mnemiopsis leidyi in the southern North Sea and Scheldt estuaries
Authors: van der Molen J. , van Beek J. , Augustine S. , Vansteenbrugge L. , van Walraven L. , Langenberg V. , van der Veer H. W. , Hostens K. , Pitois S. , Robbens J.
Published: June 2014

Abstract. Three different models were applied to study the reproduction, survival and dispersal of Mnemiopsis leidyi in the Scheldt estuaries and the southern North Sea: a high-resolution particle tracking model with passive particles, a low resolution particle tracking model with a reproduction model coupled to a biogeochemical model, and a dynamic energy budget (DEB) model. The results of the models, each with its strengths and weaknesses, suggest the following conceptual situation: (i) the estuaries possess enough retention capability to keep an overwintering population, and enough exchange with coastal waters of the North Sea to seed offshore populations; (ii) M. leidyi can survive in the North Sea, and be transported over considerable distances, thus facilitating connectivity between coastal embayments; (iii) under current climatic conditions, M. leidyi may not be able to reproduce in large numbers in coastal and offshore waters of the North Sea, but this may change with global warming – however this result is subject to substantial uncertainty. Further quantitative observational work is needed on the effects of temperature, salinity and food availability on reproduction and on mortality at different life stages to improve models such as used here.
Quantifying soil and critical zone variability in a forested catchment through digital soil mapping
Authors: Holleran M. , Levi M. , Rasmussen C.
Published: June 2014

Abstract. Quantifying catchment scale soil property variation yields insights into critical zone evolution and function. The objective of this study was to quantify and predict the spatial distribution of soil properties within a high elevation forested catchment in southern AZ, USA using a combined set of digital soil mapping (DSM) and sampling design techniques to quantify catchment scale soil spatial variability. The study focused on a 6 ha catchment on granitic parent materials under mixed-conifer forest, with a mean elevation of 2400 m a.s.l., mean annual temperature of 10 °C and mean annual precipitation of ~ 85 cm yr−1. The sample design was developed using a unique combination of iterative principal component analysis (iPCA) of environmental covariates derived from remotely sensed imagery and topography, and a conditioned Latin Hypercube Sampling (cLHS) scheme. Samples were collected by genetic horizon from 24 soil profiles excavated to the depth of refusal and characterized for soil mineral assemblage, geochemical composition, and general soil physical and chemical properties. Soil properties were extrapolated across the entire catchment using a combination of least squares linear regression between soil properties and selected environmental covariates, and spatial interpolation or regression residual using inverse distance weighting (IDW). Model results indicated that convergent portions of the landscape contained deeper soils, higher clay and carbon content, and greater Na mass loss relative to adjacent slopes and divergent ridgelines. The results of this study indicated that: (i) the coupled application of iPCA and cLHS produced a sampling scheme that captured the majority of catchment scale soil variability; (ii) application of relatively simple regression models and IDW interpolation of residuals described well the variance in measured soil properties and predicted spatial correlation of soil properties to landscape structure; and (iii) at this scaleof observation, 6 ha catchment, topographic covariates explained more variation in soil properties than vegetation covariates. The DSM techniques applied here provide a framework for interpreting catchment scale variation in critical zone process and evolution. Future work will focus on coupling results from this coupled empirical-statistical approach to output from mechanistic, process-based numerical models of critical process and evolution.
Coupled cellular automata for frozen soil processes
Authors: Nagare R. M. , Bhattacharya P. , Khanna J. , Schincariol R. A.
Published: June 2014

Abstract. Heat and water movement in variably saturated freezing soils is a tightly coupled phenomenon. Strong coupling of water and heat movement in frozen soils moves considerable amounts of water from warmer to colder zones. The coupling is a result of effects of sub-zero temperature on soil water potential, heat carried by water moving under pressure gradients, and dependency of soil thermal and hydraulic properties on soil water content. This makes water and heat movement in variably saturated soils a highly non-linear process in mathematical terms. This study presents a one-dimensional cellular automata (direct solving) model to simulate coupled heat and water transport with phase change in variably saturated soils. The model is based on first order mass and energy conservation principles. The water and energy fluxes are calculated using first order empirical forms of Buckingham–Darcy's law and Fourier's heat law, respectively. The water-ice phase change is handled by integrating along experimentally determined soil freezing curve (unfrozen water content and temperature relationship) obviating the use of apparent heat capacity term. This approach highlights a further subtle form of coupling one in which heat carried by water perturbs the water content – temperature equilibrium and exchange energy flux is used to maintain the equilibrium rather than affect temperature change. The model is successfully tested against analytical and experimental solutions. Setting up a highly non-linear coupled soil physics problem with a physically based approach provides intuitive insights into an otherwise complex phenomenon.
Carbon nanomaterials in clean and contaminated soils: environmental implications and applications
Authors: Riding M. J. , Martin F. L. , Jones K. C. , Semple K. T.
Published: June 2014

Abstract. The exceptional sorptive ability of carbon nanomaterials (CNMs) for hydrophobic organic contaminants (HOCs) is driven by their characteristically large reactive surface areas and highly hydrophobic nature. Given these properties, it is possible for CNMs to impact on the persistence, mobility and bioavailability of contaminants within soils, either favourably through sorption and sequestration, hence reducing their bioavailability, or unfavourably through increasing contaminant dispersal. This review considers the complex and dynamic nature of both soil and CNM physicochemical properties to determine their fate and behaviour, together with their interaction with contaminants and the soil micro-flora. It is argued that assessment of CNMs within soil should be conducted on a case-by-case basis, and further work to assess the long-term stability of sorbed contaminants and the toxicity of CNMs is required before their sorptive abilities can be applied to remedy environmental issues.
Self-Reliance and the Portability of Pragmatism
Authors: Neville Robert Cummings
Published: June 2014

Flush with the juices of adolescence, American philosophy declared independence from its European parentage in the work of Ralph Waldo Emerson and his generation. In 1837, Emerson addressed the Harvard Phi Beta Kappa Society on the occasion of its inaugural meeting for the year, which he called a "holiday." Emerson began: I greet you on the recommencement of our literary year. Our anniversary is one of hope, and, perhaps, not enough of labor. We do not meet for games of strength or skill, for the recitation of histories, tragedies, and odes, like the ancient Greeks; for parliaments of love and poesy, like the Troubadours; nor for the advancement of science, like our contemporaries in the British and European capitals. Thus far, our holiday has been simply a friendly sign of the survival of the love of letters amongst a people too busy to give letters any more. Perhaps the time is already come when it ought to be, and will be something else; when the sluggard intellect of this continent will look from under its iron lids and fill the postponed expectations of the world with something better than the expectations of mechanical skill. Our day of dependence, our long apprenticeship to the learning of other lands, draws to a close. The millions that around us are rushing into life, cannot always be fed on the sere remains of foreign harvests. Events, actions arise, that must be sung, that will sing themselves.
George Santayana and the Problem of Petitionary Prayer
Authors: Clanton J. Caleb
Published: June 2014

Scholars of the classical American philosophical tradition have not written much about prayer, despite the fact that almost every single one of the major figures of this tradition acknowledged its significance. The gap in the literature is notable in the case of George Santayana, who discusses prayer in several of his major works. And of all the classical American philosophers, Santayana may have the most fully developed treatment of prayer, particularly as it relates to the problem of petitionary prayer. Yet his account of payer has not received much attention. This is surprising since, on the one hand, many of Santayana’s other views on religion and spirituality have been widely commented on, and, on the other hand, prayer has been a prominent topic in philosophy of religion in recent decades. And it makes sense for scholars of the classical American tradition nowadays to consider Santayana’s views about prayer, at the least because this tradition concerns itself with the problems of ordinary people, and to most Americans–and even to some atheist Americans–prayer seems to matter a great deal. Santayana’s treatment of prayer can be organized into two phases. First, he offers a twofold case against the common view that petitionary prayer is materially efficacious–that is, the view that petitionary prayer can do something to affect whether God brings about a desired state of affairs that would not have otherwise obtained had the request for it not been made.
Taxonomic uncertainty of Stachytarpheta (Verbenaceae) in the Asia-Pacific and implications for invasive weed recognition and management
Authors: Chandler Gregory Thomas , Westaway John O , Conn Barry John
Published: June 2014

Stachytarpheta indica has been regarded as an agricultural weed occurring throughout south-east Asia. In Australia, it is classified as a prospective invasive weed by the Northern Australia Quarantine Strategy (Brown et al. 2008). After examining several papers from the 1990’s, we conclude that there is no evidence to support S. indica being in this region at all and that the name has been historically misapplied to several other species of Stachytarpheta. A table of characters is provided for four species of Stachytarpheta showing major character differences and highlights the confusion still surrounding some of the species. Additionally, Stachytarpheta cayennensis should be added to the flora of Christmas Island, while the taxonomic status of S. urticifolia needs to be examined in further detail.
Sediment and carbon fluxes along a longitudinal gradient in the lower Tana River (Kenya)
Authors: Tamooh Fredrick , Meysman Filip J. R. , Borges Alberto V. , Marwick Trent R. , Van Den Meersche Karel , Dehairs Frank , Merckx Roel , Bouillon Steven
Published: June 2014

We estimated annual fluxes of suspended matter and different carbon (C) pools at three sites along the lower Tana River (Kenya), based on monthly sampling between January 2009 and December 2011. Concentrations of total suspended matter (TSM), particulate organic carbon (POC), dissolved organic carbon (DOC), and dissolved inorganic carbon (DIC) were monitored, as was the stable isotope composition of the carbon pools. Both TSM and POC concentrations showed strong seasonality, varying over several orders of magnitude, while DOC and DIC concentrations showed no seasonal variations. A strong shift in the origin of POC was observed, which was dominated by C3‐derived C during dry conditions (low δ13CPOC between −28‰ and −25‰), but had significant C4 contributions during high‐flow events (δ13CPOC up to −19.5‰). Between Garissa and the most downstream sampling point, a clear decrease in suspended matter and organic C fluxes was observed, being most pronounced during high‐discharge conditions: on an annual basis, fluxes of TSM, POC, and DIC decreased by 34% to 65% for the 3 year study period. Our results suggest that floodplains along the lower Tana River could play an important role in regulating the transport of suspended matter and organic C. A comparison of current flux estimates with data collected prior to the construction of several hydropower dams reveals that the sediment loading is reduced during low discharge conditions.
The radiative impact of water ice clouds from a reanalysis of Mars Climate Sounder data
Authors: Steele L. J. , Lewis S. R. , Patel M. R.
Published: June 2014

The radiative impact of water ice clouds on the atmosphere of Mars is analyzed via a reanalysis of Mars Climate Sounder (MCS) temperature and ice opacity profiles. Polar hood clouds only have a small radiative impact, while tropical clouds increase diurnally averaged temperatures at the 10 Pa level by ∼10–15 K. Cloud radiative heating strengthens the meridional overturning circulation, increasing temperatures in the polar warmings by ∼6–8 K and temperatures in the tropics by ∼2 K (due to increased dust mass). The positions and wind speeds of the tropical and high‐latitude jets are also modified through changes to the meridional temperature gradients. An effective ice particle radius of reff=1.4μm produces temperatures around the aphelion cloud belt in close agreement to MCS temperature retrievals. For high‐altitude tropical clouds during northern autumn, a better agreement is found using reff=0.8μm.
Effects of Smoking and Shared Epitope on the Production of Anti–Citrullinated Peptide Antibody in a Japanese Adult Population
Authors: Terao Chikashi , Ohmura Koichiro , Ikari Katsunori , Kawaguchi Takahisa , Takahashi Meiko , Setoh Kazuya , Nakayama Takeo , Kosugi Shinji , Sekine Akihiro , Tabara Yasuharu , Taniguchi Atsuo , Momohara Shigeki , Yamanaka Hisashi , Yamada Ryo , Matsuda Fumihiko , Mimori Tsuneyo ,   on Behalf of the Nagahama Study Group
Published: June 2014

Objective

Anti–citrullinated peptide antibody (ACPA) and rheumatoid factor (RF) are markers to rheumatoid arthritis (RA). Smoking and shared epitope (SE) in HLA–DRB1 are associated with the production of these autoantibodies in RA. Detailed distribution and characterization of ACPA and RF in the general population have remained unclear. We aimed to evaluate positivity of ACPA and RF in a general Japanese population and to detect correlates, including genetic components.

Methods

ACPA and RF were quantified in 9,804 Japanese volunteers ages 30–75 years. Logistic regression analyses were performed to evaluate the effects of candidates of correlates on the autoantibody positivity. A genome‐wide association study (GWAS) was performed using 394,239 single nucleotide polymorphisms for 3,170 participants, and HLA–DRB1 alleles were imputed based on the GWAS data.

Results

A total of 1.7% and 6.4% of subjects were positive for ACPA and RF, respectively, and the 2 markers showed a significant correlation (P = 2.0 × 10−23). Old age was associated with ACPA positivity (P = 0.00062). Sex, smoking, SE, and other candidates of correlates did not have significant effects. Interaction between smoking and SE positivity was not apparent, but smoking showed a significant association with high levels of ACPA (P = 0.0019).

Conclusion

ACPA and RF could be detected in 1.7% and 6.4% of the Japanese adult population without RA, respectively. ACPA and RF were suggested to share mechanisms even in healthy populations. Old age was associated with increasing ACPA positivity. While positivity of ACPA and RF was not associated with SE and smoking, an association between high ACPA and smoking was observed.
Infrared Wavefront Control Based on Graphene Metasurfaces
Authors: Lu Feifei , Liu Baoan , Shen Sheng
Published: June 2014

Metasurfaces, a new class of planar metamaterial, are attracting intensive attention due to their exceptional abilities to mold light. In this work, novel metasurfaces based on graphene nanoribbons are developed to control the wavefront of infrared light. The results show that these metasurfaces can create phase discontinuities between incident and scattered light, covering the phase range from 0 to about π while maintaining a relatively large amplitude for the scattered light. A cylindrical flat lens and anomalous refraction based on graphene nanoribbon metasurfaces are also demonstrated, paving the way to developing graphene‐based tunable devices for infrared wavefront control.
Safety of bosutinib versus imatinib in the phase 3 BELA trial in newly diagnosed chronic phase chronic myeloid leukemia
Authors: Gambacorti‐Passerini Carlo , Cortes Jorge E. , Lipton Jeff H. , Dmoszynska Anna , Wong Raymond S. , Rossiev Victor , Pavlov Dmitri , Gogat Marchant Karin , Duvillié Ladan , Khattry Navin , Kantarjian Hagop M. , Brümmendorf Tim H.
Published: June 2014

Bosutinib, an orally active, Src/Abl tyrosine kinase inhibitor, has demonstrated clinical activity and acceptable tolerability in chronic phase chronic myeloid leukemia (CP CML). This updated analysis of the BELA trial assessed the safety profile and management of toxicities of bosutinib versus imatinib in adults with newly diagnosed (≤6 months) CP CML after >30 months from accrual completion. Among patients randomized to bosutinib 500 mg/d (n = 250) or imatinib 400 mg/d (n = 252), 248 and 251, respectively, received ≥1 dose of study treatment. Adverse events (AEs; any grade) with bosutinib versus imatinib were significantly more common for certain gastrointestinal events (diarrhea, 70% vs. 26%; P < 0.001; vomiting, 33% vs. 16%; P < 0.001), alanine aminotransferase (33% vs. 9%; P < 0.001) and aspartate aminotransferase (28% vs. 10%; P < 0.001) elevations, and pyrexia (19% vs. 12%; P = 0.046). AEs significantly less common with bosutinib included edema (periorbital, 2% vs. 14%; P < 0.001; peripheral, 5% vs. 12%; P = 0.006), musculoskeletal (myalgia, 5% vs. 12%; P = 0.010; muscle cramps, 5% vs. 22%; P < 0.001; bone pain, 4% vs. 11%; P = 0.003), increased creatine phosphokinase (8% vs. 20%; P < 0.001), neutropenia (13% vs. 30%; P < 0.001), and leukopenia (9% vs. 22%; P < 0.001). Between‐group differences in the incidence of cardiac and vascular AEs were not significant. Diarrhea was typically transient, mostly Grade 1/2, occurring early during treatment, and was manageable with antidiarrheal medication. Despite higher rates of aminotransferase elevation with bosutinib, events were managed in most patients with dose modification and/or concomitant medication. Bosutinib had a manageable safety profile distinct from that of imatinib in patients with newly diagnosed CP CML. Am. J. Hematol. 89:947–953, 2014. © 2014 The Authors. American Journal of Hematology Published by Wiley Periodicals, Inc.
Safe and successful bone marrow biopsy: An anatomical and CT‐based cadaver study
Authors: Konda Bhavana , Pathak Swati , Edwin Inga , Mishall Priti , Downie Sherry A. , Olson Todd R. , Reed Louis J. , Friedman Ellen W.
Published: June 2014

Bone marrow biopsy is generally a safe procedure. However, infrequently the procedure is associated with serious injuries that are attributed to inadvertent needle penetration of the iliac bone's inner cortex. An evidence‐based approach to needle orientation during iliac crest biopsy does not exist. In our study, the posterior to anterior path of the bone marrow needle from the posterior superior iliac spine (PSIS) was studied in human cadavers in two orientations: (1) perpendicularly to the coronal plane (the perpendicular approach) and (2) laterally toward the ipsilateral anterior superior iliac spine (ASIS) (the lateral approach). The biopsy needle was deliberately advanced through the inner ilial cortex in both approaches. Dissections and imaging studies were done to identify the relationship of the penetrating needle to internal structures. Both approaches begin with a perpendicular puncture of the outer cortex at the PSIS. The perpendicular approach proceeds anteriorly whereas in the lateral approach the needle is reoriented toward the ipsilateral ASIS before advancing. The lateral approach caused less damage to neurovascular structures and avoided the sacroiliac joint compared to the perpendicular approach. This procedure is best done in the lateral decubitus position. Proper use of the lateral approach should obviate many of the complications reported in the literature. Am. J. Hematol. 89:943–946, 2014. © 2014 Wiley Periodicals, Inc.