bluuebunny/crossref_metadata_2025 huggingface dataset:
Fabrication of Bulk Metallic Glass Composites at Low Processing Temperatures
Authors: Shamlaye Karl F. , Laws Kevin J. , Ferry Michael
Published: November 2013

Bulk metallic glasses (BMGs) are amorphous alloys that exhibit unique mechanical properties such as high strength due to their liquid-like structure in the vitreous solid state. While they usually exhibit low ductility, they can be toughened by incorporating secondary phase particles within the amorphous matrix via composite fabrication to generate amorphous metal matrix composites (MMCs). Traditional MMCs are fabricated at high temperature in the liquid state with tedious blending processes. This high temperature processing route often leads to unwanted reactions at the reinforcement/matrix interface, creating brittle intermetallic by-products and damaging the reinforcement. In the present work, novel bulk metallic glass composites (BMGCs) were fabricated at low processing temperatures via thermoplastic forming (TPF) above the glass transition temperature of the amorphous matrix. Here, the unique thermophysical features of the matrix material allow for TPF of composites in non-sacrificial moulds incorporating various types of reinforcement, via processing in the solid state at low temperatures (less than 200 °C), within a short timeframe (less than 10 minutes); this avoids the formation of brittle phases at the reinforcement/matrix interface leading to efficient bonding between particles and matrix, thereby creating a tough, low density composite material.
In Situ Detection of Forging Defects without Sensors in the Forging Tool
Authors: Krause Andreas , Kache Hanns , Ullmann Georg
Published: November 2013

The early detection of defects in forged parts offers economical advantages due to the possibility of sorting them out of the process chain betimes. Hence, no further production costs are occurred by those parts. However, the detection of defects during forging processes is not state of the art. Usually defects of forged parts which are often not obvious and therefore cannot be identified by the press operator are detected by measurements after cooling or later by the customer. In both cases costs occur. Due to the rough conditions in forging shop floors (e. g. high temperatures and forces) the integration of sensors monitoring the forging process is hardly viable. Within the presented research project an in-situ forging process monitoring system is developed which works without sensors in the forging tool and shows results on the process quality directly after forging. A system consisting of two independent concepts (defect-identification and filling-identification) is developed to detect typical forging process failures. On the one hand the defect-identification is able to detect e.g. wrong press energy or insert-position. On the other hand the filling-identification aims to detect, if the cavity is completely filled by the work-piece. Both concepts work in real-time with the help of a computer and a screen visualising the results. One the one hand this paper presents the results of forging trials using the defect-identification and evaluates its capability. On the other hand the concept for the filling identification is presented.
Modeling of the Behavior of an Aluminum Metallic Foam by Both FEM and Experimental Results
Authors: Fuertes Juan Pablo , Luri Rodrigo , León Javier , Salcedo Daniel , Puertas Ignacio , Luis Carmelo J.
Published: November 2013

Aluminum foams are porous metallic materials which possess an outstanding combination of physical and mechanical properties such as: a high rigidity with a very low density. In this present research work, a study on the upsetting of an aluminum foam (with a density = 0.73 g/cm3) is carried out by employing different compression velocity values. From the results obtained, it is possible to determine the material flow stress for its subsequent use in finite element simulations (FEM). Once the material flow stress has been determined, it will be employed in order to analyze the conformability of several parts by FEM.
Investigation of the Deformation Behaviour of a Thermoplastic Fibre Metal Laminate
Authors: Sexton Anthony , Cantwell Wesley , Doolan Matthew , Kalyanasundaram Shankar
Published: November 2013

Fibre metal laminates are sandwich materials comprised of a fibre-reinforced composite and a metal alloy. These advanced materials offer superior properties compared to the monolithic constituents; primarily, improved specific strength and stiffness compared to metals and improved impact and fatigue resistance when compared to composite materials. The use of these advanced materials is currently restricted to specialised applications where the superior properties justify the high cost of manufacturing. The formability of a fibre metal laminate based on a glass fibre reinforced polypropylene and an aluminium alloy is investigated in this study using techniques developed for the evaluation of metallic materials. Specimens of varying geometry were stretched over a hemispherical punch and an open die configuration was used to facilitate the acquisition of the strain using a using an optical measurement system. The experimental results were used to determine a forming limit diagram and to elucidate the safe forming limits of the material. In addition, the effect of specimen geometry on deformation behaviour was investigated by analysing the evolution of strain on the surface of the specimens. A significant finding of this study is that advanced materials such as fibre metal laminates can be formed in a similar manner to monolithic metals.
The Effect of Molecular Structure on the Adsorption of PPO-PEO-PPO Triblock Copolymers on Solid Surfaces
Authors: Lin Bing Jing , Zhu Hong Tao , Tieu A. Kiet , Kosasih Bu Yung , Triani Gerry
Published: November 2013

This paper investigates the adsorption behavior of triblock copolymer Poly (propylene oxide)-poly (ethylene oxide)-poly (propylene oxide), PPO-PEO-PPO on silicon and iron surfaces by using the contact angle goniometer, spectroscopic ellipsometer and atomic force microscopy (AFM). After adsorption, the decrease of water contact angle was observed on each surface; and a larger reduction of water contact angle occurred on the surface covered by the copolymer film with longer and higher weight percent of hydrophilic PEO block. This means that the PEO block may be on the top of the adsorbed copolymer film. The film thickness measurement shows that the copolymer with longer and higher weight percent of PPO block forms a thicker film on the hydrophobic surface, which suggests that the hydrophobic PPO block of the copolymer in the aqueous solution plays the main role during the adsorption of PPO-PEO-PPO onto the hydrophobic surface. It has been found from the AFM results that the roughness of the surface decreased after adsorption and the smoother topography was observed on the surface adsorbed by a thicker adsorbed film.
A Study on Welding Quality of Robotic Arc Welding Process Using Mahalanobis Distance Method
Authors: Chand Reenal Ritesh , Kim Ill Soo , Lee Ji Hye , Lee Jong Pyo , Shim Ji Yeon , Kim Young Su
Published: November 2013

In robotic GMA (Gas Metal Arc) welding process, heat and mass inputs are coupled and transferred by the weld arc and molten base material to the weld pool. The amount and distribution of the input energy are basically controlled by the obvious and careful choices of welding process parameters in order to accomplish the optimal bead geometry and the desired mechanical properties of the quality weldment. To make effective use of automated and robotic GMA welding, it is imperative to predict online faults for bead geometry and welding quality with respect to welding parameters, applicable to all welding positions and covering a wide range of material thickness. To successfully accomplish this objective, two sets of experiment were performed with different welding parameters; the welded samples from SM 490A steel flats adopting the bead-on-plate technique were employed in the experiment. The experimental results of current and voltage waveforms were used to predict the magnitude of bead geometry and welding quality, and to establish the relationships between weld process parameters and online welding faults. MD (Mahalanobis Distance) technique is employed for investigating and modeling of GMA welding process and significance test techniques were applied for the interpretation of the experimental data. Statistical models developed from experimental results which can be used to control the welding process parameters in order to achieve the desired bead geometry based on weld quality criteria.
Rheological Properties Analysis of WC-Co Injection Feedstock
Authors: Amin Sri Yulis M. , Muhamad Norhamidi , Jamaludin Khairur Rijal
Published: November 2013

In order to produce a defect-free component, the feedstock composition plays as a critical factor. The feedstock needs to meet the following criteria; high solid loading with excellent flowability. The flowability of the feedstock is greatly determined by the rheological response. Therefore, the aim of this paper is to investigate the rheological behaviour of MIM feedstock comprising of WC-Co powder, with a binder system of Palm Stearin (PS) and Polyethylene (PE), by means of a capillary rheometry. The viscosity and shear rate of various feedstocks at powder loading ranging from 59, 61 and 63% were measured at L/D = 10 die. The rheological properties such as flow behaviour index, activation energy and moldability parameter of each feedstock were calculated and from the analysis, it was concluded that they show a good pseudo-plastic behaviour within acceptable ranges in MIM.
Surface Quality and Chip Formation in Turning of LM6 Aluminium Alloy and Particulate Reinforced Metal Matrix Composite
Authors: Yusuf Muhammad , Ariffin M.K.A. , Ismail N. , Sulaiman S.
Published: November 2013

Majority of the components of aerospace and automotive vehicles need different machining operations, mainly for the assembly requirements. The components have to present both high dimensional precision and surface quality. This present work is concerned with the effect of cutting parameters (cutting speed, feed rate and depth of cut) on the surface roughness and the chip formation in turning process. The machining results are compared with LM6 aluminium alloy and TiC reinforced metal matrix composite under the same cutting conditions and tool geometry. The cutting condition models designed based on the Design of Experiments Response Surface Methodology. The objective of this research is to obtaining the optimum cutting parameters to get a better surface quality and also the chip formation and furthermore does not hazardous to the worker and the machined products quality. Results shows that Surface roughness values of LM6-TiC composite are higher as compared LM6 alloy at similar cutting condition. With increasing in cutting speed improves the surface quality. The surface quality increases with decrease of the feed rate and the depth of cut. There are difference chip forms for LM6 aluminium alloy and Al-TiC composite for a similar of cutting condition. Generally, chip formations of both materials are acceptable and favourable for the worker as well as the products and the tools.
Development of Piercing Technology for CVJ Cage with Thick and Uneven Piercing Holes
Authors: Kim Dong Hwan , Park Se Je
Published: November 2013

In this paper, to design the piercing punch for thick and uneven steel in piercing process, FE simulation technique has been proposed to predict the deformation behavior of CVJ cage through the simulation of the piercing process. In this research, an optimizing technique based on artificial neural network has been applied for the thick and uneven steel in piercing processes to construct database of the dimension precision depending on the shape of punch. It is indicated that shape of punch plays a significant role to keep the dimension precision and to increase the tool life in the uneven piercing process.
Dielectric Properties of Pure and Strontium Doped Nano-Hydroxyapatite
Authors: Tank Kashmira P. , Jogiya Bhoomika V. , Kanchan Dinesh K. , Joshi Mihir J.
Published: November 2013

Hydroxyapatite (Ca10(PO4)6(OH)2-HAp), is an excellent inorganic biomaterial and finds various applications. As it is similar to inorganic matrix of human bone and dental enamel, pure and doped HAps are widely studied. In the present study, pure nano-HAp and Strontium doped nano-HAp (Sr-HAp) with different concentrations were synthesized by surfactant mediated approach. The doping of strontium was confirmed by EDAX. The powder XRD study was carried out and it suggested nano-crystalline nature of the sample and the extra peaks observed other than HAp were due to the presence of brushite phase for higher concentration of Sr. TEM study revealed the needle type morphology for all the samples with size ranging from 23 nm to 78 nm. The dielectric study was carried out at room temperature within the frequency range from 102 Hz to 107 Hz and the variations of dielectric constant with frequency of applied field as well as with the concentration of strontium were studied. The results are discussed.
Effect of Substrate on Memristive Switching of Pr0.7Ca0.3MnO3
Authors: Bhavsar Komal H. , Joshi Utpal S.
Published: November 2013

. Perovskite manganite Pr0.7Ca0.3MnO3 (PCMO) thin film nanostructures were grown on different substrates by chemical solution deposition to investigate its electrical switching properties. Planar structures consisting of Ag/Pr0.7Ca0.3MnO3/Ag grown on SiO2, Si (100), LaAlO3 (100) and MgO (100) were characterized by grazing incidence X-ray diffraction, atomic force microscopy and electrical measurements. In each case, single PCMO phase formation and smooth surface morphology was confirmed by XRD and AFM, respectively. Four terminal current voltage characteristics of Ag/PCMO/Ag planar geometry exhibited a sharp transition from a low resistance state (LRS) to a high resistance state (HRS) with a high resistance switching ratios of the order of 950 for PCMO films grown on quartz was estimated at room temperature. High resistance switching ratios were found to depend on the substrate, suggesting a role of lattice mismatch for resistance switching. We have observed that higher mismatch lead to better resistance switching in this compound. The observed conduction characteristics provide direct evidence of substrate strain induce resistance switching in the Pr0.7Ca0.3MnO3.
Biology of the European oak borer in Michigan, United States of America, with comparisons to the native twolined chestnut borer
Authors: Petrice Toby R. , Haack Robert A.
Published: November 2013

In 2010–2011, we studied the European oak borer (EOB),Agrilus sulcicollisLacordaire (Coleoptera: Buprestidae), in Michigan, United States of America, and made comparisons with the native twolined chestnut borer (TLCB),Agrilus bilineatus(Weber). EOB adult flight began and peaked before TLCB. More EOB females were captured on purple and white compared with yellow and green sticky traps. More TLCB females were captured on purple, followed by yellow, green, and white, respectively. Male EOB and TLCB did not show a significant colour preference. EOB completed development primarily from areas of artificially girdled trees where the phloem had died soon after trees were girdled, while TLCB usually developed in areas of girdled trees that had some live phloem present. Both EOB and TLCB successfully attacked and emerged from girdledQuercus albaLinnaeus,Quercus roburLinnaeus, andQuercus rubraLinnaeus (Fagaceae) trees. No live EOB or TLCB were found in two ungirdled and apparently healthyQ. roburtrees that were dissected. EOB attacked and emerged fromQ. alba,Q. robur,Q. rubra, andQuercus velutinaLamarck trap logs. Differences in the pronotal groove and terminal processes can be used to distinguish EOB from TLCB larvae. Five species of parasitoids were reared from EOB and four from TLCB.
Exploiting Apoptosis for Therapeutic Tolerance Induction
Authors: Getts Daniel R. , McCarthy Derrick P. , Miller Stephen D.
Published: November 2013

Immune tolerance remains the most promising yet elusive strategy for treating immune-mediated diseases. An experimental strategy showing promise in phase 1 clinical studies is the delivery of Ag cross-linked to apoptotic leukocytes using ethylene carbodiimide. This approach originated from demonstration of the profound tolerance-inducing ability of i.v. administered Ag-coupled splenocytes (Ag-SP) in mice, which has been demonstrated to treat T cell–mediated disorders including autoimmunity, allergy, and transplant rejection. Recent studies have defined the intricate interplay between the innate and adaptive immune systems in Ag-SP tolerance induction. Innate mechanisms include scavenger receptor–mediated uptake of Ag-SP by host APCs, Ag representation, and the required upregulation of PD-L1 expression and IL-10 production by splenic marginal zone macrophages leading to Ag-specific T cell regulation via the combined effects of cell-intrinsic anergy and regulatory T cell induction. In this paper, we discuss the history, advantages, current mechanistic understanding, and clinical potential of tolerance induction using apoptotic Ag-coupled apoptotic leukocytes.
A confident call to faith: Rediscovering the relevance of Christian catechisms
Authors: Potgieter Raymond
Published: November 2013

Protestant heritage is synonymous with the traditional employment of catechisms and catechetical teaching of both young and old. Many denominations have shifted from this historical approach, not least because of the challenges of so-called catechetical vacuums when facing third-millennial issues. The Heidelberg, Anglican and Westminster Catechisms allow for express distinctions peculiar to each unique Protestant faith constituency, but serve acceptably within the wider ecumenical tradition. A rediscovery of the historical contexts of these historical formulations will illustrate traditional denominational Protestant flexibility accompanying its Christian creedal fixity. This study will refer to confessional content in the main without resorting to particular content. The intention is to show how these polarities could dynamically serve the confessing church in meeting present-day challenges to the Christian faith in a manner that once again will inspire confidence in its catholic witness in the third millennium.Die protestantse erfenis is sinoniem met die tradisionele gebruik van die kategismusse en die kategetiese onderrig van oud en jonk. Baie kerkgenootskappe neig weg van hierdie historiese benadering hoofsaaklik as gevolg van die uitdagings van die sogenaamde kategetiese leemtes in die hantering van derde millenniumkwessies. Die Heidelbergse, Anglikaanse en Westminsterse Kategismusse laat ruimte vir spesifieke onderskeidings wat eie is aan elke unieke protestantse geloofsgemeenskap, maar wat nogtans binne die breër ekumeniese tradisie aanvaar word. ’n Herontdekking van die historiese konteks van hierdie tradisionele formulerings sal tradisioneel kerklik-protestantse buigsaamheid illustreer wat met konfessionele vastheid gepaard gaan. Hierdie artikel verwys na konfessionele inhoud oor die algemeen sonder om spesifieke inhoud aan te toon. Die doel is dus om aan te toon hoedanig hierdie polariteite die belydende kerk daadwerklik kan help om die daaglikse uitdagings van die Christelike geloof op so ’n wyse te hanteer dat daar weer vertroue in die algemene getuienis van die kerk in die derde millennium sal wees.
Constraints on emissions of carbon monoxide, methane, and a suite of hydrocarbons in the Colorado Front Range using observations of 14CO2
Authors: LaFranchi B. W. , Pétron G. , Miller J. B. , Lehman S. J. , Andrews A. E. , Dlugokencky E. J. , Hall B. , Miller B. R. , Montzka S. A. , Neff W. , Novelli P. C. , Sweeney C. , Turnbull J. C. , Wolfe D. E. , Tans P. P. , Gurney K. R. , Guilderson T. P.
Published: November 2013

Abstract. Atmospheric radiocarbon (14C) represents an important observational constraint on emissions of fossil-fuel derived carbon into the atmosphere due to the absence of 14C in fossil fuel reservoirs. The high sensitivity and precision that accelerator mass spectrometry (AMS) affords in atmospheric 14C analysis has greatly increased the potential for using such measurements to evaluate bottom-up emissions inventories of fossil fuel CO2 (CO2ff), as well as those for other co-emitted species. Here we use observations of 14CO2 and a series of primary hydrocarbons and combustion tracers from discrete air samples collected between June 2009 and September 2010 at the National Oceanic and Atmospheric Administration Boulder Atmospheric Observatory (BAO; Lat: 40.050° N, Lon: 105.004° W) to derive emission ratios of each species with respect to CO2ff. The BAO tower is situated at the boundary of the Denver metropolitan area to the south and a large industrial and agricultural region to the north and east, making it an ideal location to study the contrasting mix of emissions from the activities in each region. The species considered in this analysis are carbon monoxide (CO), methane (CH4), acetylene (C2H2), benzene (C6H6), and C3–C5 alkanes. We estimate emissions for a subset of these species by using the Vulcan high resolution CO2ff emission data product as a reference. We find that CO is overestimated in the 2008 National Emissions Inventory (NEI08) by a factor of ~2. A close evaluation of the inventory suggests that the ratio of CO emitted per unit fuel burned from on-road gasoline vehicles is likely over-estimated by a factor of 2.5. Using a wind-directional analysis of the data, we find enhanced concentrations of CH4, relative to CO2ff, in air influenced by emissions to the north and east of the BAO tower when compared to air influenced by emissions in the Denver metro region to the south. Along with enhanced CH4, the strongest enhancements of the C3–C5 alkanes are also found in the north and east wind sector, suggesting that both the alkane and CH4 enhancements are sourced from oil and gas fields located to the northeast, though it was not possible to rule out the contribution of non oil and gas CH4 sources.
A naming convention for atmospheric organic aerosol
Authors: Murphy B. N. , Donahue N. M. , Robinson A. L. , Pandis S. N.
Published: November 2013

Abstract. We present a naming convention for classifying organic aerosol (OA) components relevant to laboratory studies, ambient observations and models. The challenge of developing a unified, systematic naming system is formidable, due to the wealth of chemical species involved in atmospheric OA, the distribution of these species between multiple simultaneously occurring phases, the large number of possible formation pathways, the growing diversity of measurement techniques available, and the numerous contexts in which OA is discussed. We propose such a system based on the volatility basis set approach that lumps organic compounds by similar effective saturation concentration. The volatility classes included in this convention (extremely low volatility, low volatility, semivolatile, intermediate volatility, and volatile), combined with more commonly used terms (e.g. primary and secondary OA, biomass burning OA, etc.) are able to describe and distinguish between several different routes of OA formation in the atmosphere, making them useful for communicating model, laboratory, and field results. Also useful is the addition of a suffix representing the volatility of the OA mass or its precursor during emission. This helps connect the current, dynamic view of OA phenomenology with the traditional, static one. Connections between the terms proposed here and observational techniques in the field, including dilution sampling, aerosol mass spectrometry, etc., are also discussed.
On the link between the Amazonian forest properties and shallow cumulus cloud fields
Authors: Heiblum R. H. , Koren I. , Feingold G.
Published: November 2013

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 landcover 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 secondary to the higher order effects of meteorology and biomass burning, a clear positive linear relation between EVI (i.e. surface properties) and FCu field occurrence is seen over forest landcover, implying a strong coupling between forest surface fluxes and the cloud organization above. Over non-forest landcover the relation between EVI and FCu occurrence is non-linear, 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 landcover dependencies.
Assessment of cloud supersaturation by aerosol particle and cloud condensation nuclei (CCN) measurements
Authors: Krüger M. L. , Mertes S. , Klimach T. , Cheng Y. , Su H. , Schneider J. , Andreae M. O. , Pöschl U. , Rose D.
Published: November 2013

Abstract. In this study we show how size-resolved measurements of aerosol particles and cloud condensation nuclei (CCN) can be used to characterize the supersaturation of water vapor in a cloud. The method was developed and applied for the investigation of a cloud event during the ACRIDICON-Zugspitze campaign (17 September to 4 October 2012) at the high-alpine research station Schneefernerhaus (German Alps, 2650 m a.s.l.). Number size distributions of total and interstitial aerosol particles were measured with a scanning mobility particle sizer (SMPS), and size-resolved CCN efficiency spectra were recorded with a CCN counter system operated at different supersaturation levels. During the evolution of a cloud, aerosol particles are exposed to different supersaturation levels. We outline and compare different estimates for the lower and upper bounds (Slow, Shigh) and the average value (Savg) of peak supersaturation encountered by the particles in the cloud. For the investigated cloud event, we derived Slow ≈ 0.19–0.25%, Shigh ≈ 0.90–1.64% and Savg ≈ 0.38–0.84%. Estimates of Slow, Shigh and Savg based on aerosol size distribution data require specific knowledge or assumptions of aerosol hygroscopicity, which are not required for the derivation of Slow and Savg from the size-resolved CCN efficiency spectra.
Picoplankton community structure before, during and after convection event in the offshore waters of the southern Adriatic Sea
Authors: Najdek M. , Paliaga P. , Šilović T. , Batistić M. , Garić R. , Supić N. , Ivančić I. , Ljubimir S. , Korlević M. , Jasprica N. , Hrustić E. , Dupčić-Radić I. , Blažina M. , Orlić S.
Published: November 2013

Abstract. This paper documents the picoplankton community's response to changes in oceanographic conditions in the period between October 2011 and September 2012 at two stations belonging to South Adriatic Pit (SAP). The recorded data include the community's abundance, composition, prokaryotic production rates and bacterial metabolic capacity. The aforementioned interval included an intense sea cooling with formation of exceptionally, record-breaking dense water. We documented an especially intense winter convection episode that completely diluted the core of Levantine intermediate waters (LIW) in a large area encompassing the SAP's center and its margin. During this convection event the whole picoplankton community had significantly higher abundances with a recorded picoeukaryotic peak at the SAP margin. In the post-convection phase in March prokaryotic heterotrophic production strongly increased in the entire SAP area (up to 50 times; 456.8 nM C day−1). The autotrophic biomass increase (up to 5 times; 4.86 μg L−1) and a disruption of a close correspondence between prokaryotic heterotrophic biomass production and cell replication rates were observed only in the center of the SAP, which was not under the influence of LIW. At the SAP's margin such an effect was attenuated by LIW, since the waters affected by LIW were characterized by decreased concentrations of dissolved inorganic nitrogen, decreased autotrophic biomasses and by increased bacterial biomass production balanced with cell replication rates as well as by the domination of Synechococcus among autotrophic picoplankton. Metabolic capacity was the lowest in spring when autotrophic biomass largely increased, while the highest levels found in the pre-convection phase (October 2011) suggests that the system was more oligotrophic before than after the convection event. Furthermore, we showed that metabolic capacity is a trait of bacterial community independent of environmental conditions and tightly linked to cell replication and substrate availability. On the other hand the bacterial community composition appears to be strongly influenced by physico-chemical characteristics of waters (e.g. temperature and nutrients) and environmental forcing (e.g. convection and LIW).
Peak glacial 14C ventilation ages suggest major draw-down of carbon into the abyssal ocean
Authors: Sarnthein M. , Schneider B. , Grootes P. M.
Published: November 2013

Abstract. Ice core records demonstrate a glacial–interglacial atmospheric CO2 increase of ~ 100 ppm, while 14C calibration efforts document a strong decrease in atmospheric 14C concentration during this period. A calculated transfer of ~ 530 Gt of 14C-depleted carbon is required to produce the deglacial coeval rise of carbon in the atmosphere and terrestrial biosphere. This amount is usually ascribed to oceanic carbon release, although the actual mechanisms remained elusive, since an adequately old and carbon-enriched deep-ocean reservoir seemed unlikely. Here we present a new, though still fragmentary, ocean-wide Δ14C data set showing that during the Last Glacial Maximum (LGM) and Heinrich Stadial 1 (HS-1) the maximum 14C age difference between ocean deep waters and the atmosphere exceeded the modern values by up to 1500 14C yr, in the extreme reaching 5100 14C yr. Below 2000 m depth the 14C ventilation age of modern ocean waters is directly linked to the concentration of dissolved inorganic carbon (DIC). We propose as a working hypothesis that the modern regression of DIC vs. Δ14C also applies for LGM times, which implies that a mean LGM aging of ~ 600 14C yr corresponded to a global rise of ~ 85–115 μmol DIC kg−1 in the deep ocean. Thus, the prolonged residence time of ocean deep waters may indeed have made it possible to absorb an additional ~ 730–980 Gt DIC, one third of which possibly originated from intermediate waters. We also infer that LGM deep-water O2 dropped to suboxic values of < 10 μmol kg−1 in the Atlantic sector of the Southern Ocean, possibly also in the subpolar North Pacific. The deglacial transfer of the extra-aged, deep-ocean carbon to the atmosphere via the dynamic ocean–atmosphere carbon exchange would be sufficient to account for two trends observed, (1) for the increase in atmospheric CO2 and (2) for the 190‰ drop in atmospheric Δ14C during the so-called HS-1 "Mystery Interval", when atmospheric 14C production rates were largely constant.
Seismic constraints on dynamic links between geomorphic processes and routing of sediment in a steep mountain catchment
Authors: Burtin A. , Hovius N. , McArdell B. W. , Turowski J. M. , Vergne J.
Published: November 2013

Abstract. Landscape dynamics are determined by interactions amongst geomorphic processes. These interactions allow the effects of tectonic, climatic and seismic perturbations to propagate across topographic domains, and permit the impacts of geomorphic process events to radiate from their point of origin. Visual remote sensing and in situ observations do not fully resolve the spatiotemporal patterns of surface processes in a landscape. As a result, the mechanisms and scales of geomorphic connectivity are poorly understood. Because many surface processes emit seismic signals, seismology can determine their type, location and timing with a resolution that reveals the operation of integral landscapes. Using seismic records, we show how hillslopes and channels in an Alpine catchment are interconnected to produce evolving, sediment-laden flows. This is done for a convective storm, which triggered a sequence of hillslope processes and debris flows. We observe the evolution of these process events and explore the operation of two-way links between mass wasting and channel processes that are fundamental to the dynamics of most erosional landscapes. We also track the characteristics and propagation of flows along the debris flow channel, relating changes of observed energy to the deposition/mobilization of sediments, and using the spectral content of debris flow seismic signals to qualitatively infer sediment characteristics and channel abrasion potential. This seismological approach can help to test theoretical concepts of landscape dynamics, and yield understanding of the nature and efficiency of links between individual geomorphic processes that is required to accurately model landscape dynamics under changing tectonic or climatic conditions, and to anticipate the natural hazard risk associated with specific meteorological events.
Resolving conflicts over trans-boundary rivers using bankruptcy methods
Authors: Zarezadeh M. , Madani K. , Morid S.
Published: November 2013

Abstract. A bankruptcy approach is proposed for resolving trans-boundary rivers conflicts in which the total water demand or claim of the riparian parties is more than the available water. Bankruptcy solution methods can allocate the available water to the conflicting parties with respect to their claims. Four bankruptcy rules are used here to allocate the available water to the riparian parties. Given the non-uniform spatial and temporal distribution of water across river basins, bankruptcy optimization models are proposed to allocate water based on these rules with respect to time sensitivity of water deliveries during the planning horizon. Once allocation solutions are developed, their acceptability and stability must be evaluated. Thus, a new stability index method is developed for evaluating the acceptability of bankruptcy solutions. To show how the bankruptcy framework can be helpful in practice, the suggested methods are applied to a real-world tarns-boundary river system with eight riparians under various hydrologic regimes. Stability analysis based on the proposed stability index method suggests that the acceptability of allocation rules is sensitive to hydrologic conditions and demand values. This finding has an important policy implication suggesting that fixed allocation rules and trans-boundary treaties may not be reliable for securing cooperation over trans-boundary water resources as they are vulnerable to changing socio-economic and climatic conditions as well as hydrologic non-stationarity.
Comment on "A hybrid model of self organizing maps and least square support vector machine for river flow forecasting" by Ismail et al. (2012)
Authors: Fahimi F. , El-Shafie A. H.
Published: November 2013

Abstract. Without a doubt, river flow forecasting is one of the most important issues in water engineering field. There are lots of forecasting techniques, which have successfully been utilized by previously conducted studies in water resource management and water engineering. The study of Ismail et al. (2012) which has been published in Journal of Hydrology and Earth System Sciences in 2012 was a valuable research that investigated the combination of two effective methods (self-organizing map and least squares support vector machine) for river flow forecasting. The goal was to make a comparison between the performances of SOM-LSSVM, autoregressive integrated moving average (ARIMA), artificial neural network (ANN) and least squares support vector machine (LSSVM) models for river flow prediction. This comment attempts to focus on some parts of the original paper that need more discussion. The emphasis here is to provide more information about the accuracy of the observed river flow data and the optimum map size for SOM mode as well.
Calibration and validation of SWAT model and estimation of water balance components of Shaya mountainous watershed, Southeastern Ethiopia
Authors: Shawul A. A. , Alamirew T. , Dinka M. O.
Published: November 2013

Abstract. To utilize water resources in a sustainable manner, it is necessary to understand the quantity and quality in space and time. This study was initiated to evaluate the performance and applicability of the physically based Soil and Water Assessment Tool (SWAT) model in analyzing the influence of hydrologic parameters on the streamflow variability and estimation of monthly and seasonal water yield at the outlet of Shaya mountainous watershed. The calibrated SWAT model performed well for simulation of monthly streamflow. Statistical model performance measures, coefficient of determination (r2) of 0.71, the Nash–Sutcliffe simulation efficiency (ENS) of 0.71 and percent difference (D) of 3.69, for calibration and 0.76, 0.75 and 3.30, respectively for validation, indicated good performance of the model simulation on monthly time step. Mean monthly and annual water yield simulated with the calibrated model were found to be 25.8 mm and 309.0 mm, respectively. Overall, the model demonstrated good performance in capturing the patterns and trend of the observed flow series, which confirmed the appropriateness of the model for future scenario simulation. Therefore, SWAT model can be taken as a potential tool for simulation of the hydrology of unguaged watershed in mountainous areas, which behave hydro-meteorologically similar with Shaya watershed. Future studies on Shaya watershed modeling should address the issues related to water quality and evaluate best management practices.
Origami-like creases in sheet materials for compliant mechanism design
Authors: Francis K. C. , Blanch J. E. , Magleby S. P. , Howell L. L.
Published: November 2013

Abstract. The purpose of this research is to evaluate the creasing of non-paper sheet materials, such as plastics and metals, to facilitate origami-based compliant mechanism design. Although it is anticipated that most origami-based design will result from surrogate folds (indirect methods of replacing the crease), it is valuable to provide information that may help in more direct approaches for origami-based design in materials other than paper. Planar sheets of homogeneous material are considered as they maintain the principles fundamental to origami (flat initial state, low cost, readily available). The reduced stiffness along the axis of the crease is an enabling characteristic of origami. Hence a metric based on the deformation of the crease compared to the deformation of the panels enables engineering materials to be evaluated based on their ability to achieve the "hinge-like" behavior observed in folded paper. Advantages of both high and low values of this metric are given. Testing results (hinge indexes, residual angles, localized hinge behavior and cyclic creasing to failure) are presented for various metals and polymers. This methodology and subsequent findings are provided to enable origami-based design of compliant mechanisms.
Pre-, co-, and post- rockslide analysis with ALOS/PALSAR imagery: a case study of the Jiweishan rockslide, China
Authors: Zhao C. , Zhang Q. , Yin Y. , Lu Z. , Yang C. , Zhu W. , Li B.
Published: November 2013

Abstract. On 5 June 2009, a catastrophic rockslide debris flow occurred at the crest of the Jiweishan range, Chongqing Municipality, China, killing 74 people and injuring an additional eight. We use L-band ALOS/PALSAR imagery to address landslide processes before, during and after the slide. We employ three different SAR methods, i.e., short baseline subsets (SBAS) interferometric SAR (InSAR), SAR backscattering intensity change, and InSAR stacking algorithm, to study any ground deformation before the rockslide, investigate the affected area, and calculate the topographic change by this slide, respectively. First, continuous deformation has been observed based on the available ALOS/PALSAR InSAR imagery during June and December 2007. Second, the area affected by the landslide can be inferred based on changes in SAR backscattering intensity as well as surface topography, with an estimated area of 0.47 million m2. Last, an InSAR-derived post-slide digital elevation model has allowed us to estimate surface height changes due to the slide, reaching about −80 m at the source region and about 60 m in the deposit region, respectively. Our InSAR-derived estimates have been validated using in situ data and 3-D lidar measurements.
On the behavior of site effects in Central Mexico (the Mexican Volcanic Belt – MVB), based on records of shallow earthquakes that occurred in the zone between 1998 and 2011
Authors: Clemente-Chavez A. , Zúñiga F. R. , Lermo J. , Figueroa-Soto A. , Valdés C. , Montiel M. , Chavez O. , Arroyo M.
Published: November 2013

Abstract. The Mexican Volcanic Belt (MVB) is a seismogenic zone that transects the central part of Mexico with an east–west orientation. The risk and hazard seismic of this seismogenic zone has not been studied at detail due to the scarcity of instrumental data as well as because seismicity in the continental regimen of Central Mexico is not too frequent, however, it is known that there are precedents of large earthquakes (Mw > 6.0) that have taken place in this zone. The Valley of Mexico City (VM) is the sole zone, within the MVB, which has been studied in detail; mainly focusing on the ground amplification during large events such as the 1985 subduction earthquake that occurred in Michoacan. The purpose of this article is to analyze the behavior of site effects in the MVB zone based on records of shallow earthquakes (data not reported before) that occurred in the zone between 1998 and 2011. We present a general overview of site effects on the MVB, a classification of the stations in order to reduce the uncertainty in the data to obtain attenuation parameters in future works, and some comparisons between the information presented here and that presented in previous studies. A regional evaluation of site effects and Fourier Acceleration Spectrum (FAS) shape was estimated based on 80 records of 22 shallow earthquakes within the MVB zone. Data of 25 stations were analyzed. Site effects were estimated by using the Horizontal-to-Vertical Spectral Ratio (HVSR) methodology. The results show that seismic waves are less amplified in the northeast sites of the MVB with respect to the rest of the zone and that it is possible to classify two groups of stations: (1) stations with Negligible Site Amplification (NSA) and (2) stations with Significant Site Amplification (SSA). Most of the sites in the first group showed small (< 3) amplifications while the second group showed amplifications ranging from 4 to 6.5 at frequencies of about 0.35, 0.75, 15 and 23 Hz. With these groups of stations, average levels of amplification were contrasted for the first time with those caused by the subduction zone earthaquakes. With respect to the FAS shapes, most of them showed similarities at similar epicentral distances. Finally, some variations of site effects were found when compared to those obtained in previous studies on different seismicity regions. These variations were attributed to the location of the source. These aspects help to advance the understanding about the amplification behavior and of the expected seismic risk on the Central Mexico due to large earthquakes within the MVB seismogenic zone.
Recent extreme light sea ice years in the Canadian Arctic Archipelago: 2011 and 2012 eclipse 1998 and 2007
Authors: Howell S. E. L. , Wohlleben T. , Komarov A. , Pizzolato L. , Derksen C.
Published: November 2013

Abstract. Remarkably low mean September sea ice area in the Canadian Arctic Archipelago (CAA) was observed in 2011 (146 × 103 km2), a record-breaking level that was nearly exceeded in 2012 (150 × 103 km2). These values were lower than previous September records set in 1998 (200 × 103 km2) and 2007 (220 × 103 km2), and are ∼60% lower than the 1981–2010 mean September climatology. In this study, the processes contributing to the extreme light years of 2011 and 2012 were investigated, compared to previous extreme minima of 1998 and 2007, and contrasted against historic summer seasons with above average September ice area. The 2011 minimum was associated with positive June through September (JJAS) surface air temperature (SAT) and net solar radiation (K*) anomalies that facilitated rapid melt, coupled with atmospheric circulation that restricted multi-year ice (MYI) inflow from the Arctic Ocean into the CAA. The 2012 minimum was also associated with positive JJAS SAT and K* anomalies with coincident rapid melt, but further ice decline was temporarily mitigated by atmospheric circulation which drove Arctic Ocean MYI inflow into the CAA. Atmospheric circulation was comparable between 2011 and 1998 (impeding Arctic Ocean MYI inflow) and 2012 and 2007 (inducing Arctic Ocean MYI inflow). However, preconditioning was more apparent leading up to 2011 and 2012 than 1998 and 2007. The rapid melt process in 2011 and 2012 was more intense than observed in 1998 and 2007 because of the thinner ice cover being more susceptible to anomalous thermodynamic forcing. The thinner sea ice cover within the CAA in recent years has also helped counteract the processes that facilitate extreme heavy ice years. The recent extreme light years within the CAA are associated with a longer navigation season within the Northwest Passage.
ESA's Ice Sheets CCI: validation and inter-comparison of surface elevation changes derived from laser and radar altimetry over Jakobshavn Isbræ, Greenland – Round Robin results
Authors: Levinsen J. F. , Khvorostovsky K. , Ticconi F. , Shepherd A. , Forsberg R. , Sørensen L. S. , Muir A. , Pie N. , Felikson D. , Flament T. , Hurkmans R. , Moholdt G. , Gunter B. , Lindenbergh R. C. , Kleinherenbrink M.
Published: November 2013

Abstract. In order to increase the understanding of the changing climate, the European Space Agency has launched the Climate Change Initiative (ESA CCI), a program which joins scientists and space agencies into 13 projects either affecting or affected by the concurrent changes. This work is part of the Ice Sheets CCI and four parameters are to be determined for the Greenland Ice Sheet (GrIS), each resulting in a dataset made available to the public: Surface Elevation Changes (SEC), surface velocities, grounding line locations, and calving front locations. All CCI projects have completed a so-called Round Robin exercise in which the scientific community was asked to provide their best estimate of the sought parameters as well as a feedback sheet describing their work. By inter-comparing and validating the results, obtained from research institutions world-wide, it is possible to develop the most optimal method for determining each parameter. This work describes the SEC Round Robin and the subsequent conclusions leading to the creation of a method for determining GrIS SEC values. The participants used either Envisat radar or ICESat laser altimetry over Jakobshavn Isbræ drainage basin, and the submissions led to inter-comparisons of radar vs. altimetry as well as cross-over vs. repeat-track analyses. Due to the high accuracy of the former and the high spatial resolution of the latter, a method, which combines the two techniques will provide the most accurate SEC estimates. The data supporting the final GrIS analysis stem from the radar altimeters on-board Envisat, ERS-1 and ERS-2. The accuracy of laser data exceeds that of radar altimetry; the Round Robin analysis has, however, proven the latter equally capable of dealing with surface topography thereby making such data applicable in SEC analyses extending all the way from the interior ice sheet to margin regions. This shows good potential for a~future inclusion of ESA CryoSat-2 and Sentinel-3 radar data in the analysis, and thus for obtaining reliable SEC estimates throughout the entire GrIS.