bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Grinding Speed on Energy Partition for Grinding of Inconel 718 with Vitrified CBN Wheels
Authors: Ping Bo , Fu Yu Can , Zhang Zhi Wei , Zhao Zheng Cai
Published: October 2013

An investigation is reported of the effect of grinding speed on energy partition for grinding of Inconel 718 with virtrified CBN wheels. Temperature was measured in the ground surface of Inconel 718 with semi-natural thermalcouple. The energy partition and heat flux distribution within the grinding zone were estimated and analyzed. The result indicates that low energy partitions were found to be convected into the workpiece and wheel, both were lower than 10%, and the energy partition into the coolant decreases greatly from 75% to 25% while the one into the grinding chips increases from 15% to 70% with the increasing speed.
Micro-Displacement, Stain and Stress Measurement Based on Electronic Speckle Pattern Interferometry
Authors: Wan Yun , Zhao Ping , Cui Sheng Fu , Yang Yin Fei , Li Liang
Published: October 2013

A micro-displacement, strain and stress measurement method based on electronic speckle pattern interferometry (ESPI) technique is proposed, and the measuring device is designed. Two symmetric laser beams are illuminated on the optical rough surface of a steel cantilever beam, and then speckle images are photographed by CCD. A series of filtering processing is carried out for subtracted images and FEM analysis is performed. Using the speckle fringe patterns finally achieved, displacement, strain and stress can be calculated. By comparing displacement, strain and stress measured by this method with simulation results, feasibility and engineering application value of this method have been proved.
Research on Cutting Force Characteristics of Laser and Ultrasonic Assisted Cutting of Sintered Tungsten Carbide with FEA Method
Authors: Jiao Feng , Li Feng Bian , Duan Peng
Published: October 2013

Based on the application of elliptical vibration cutting method to precision machining of hard and brittle materials and material softening technology through laser heating, a novel composite cutting technique, laser heating and ultrasonic elliptical vibration assisted cutting, is applied to process sintered tungsten carbide. The simulation of the orthogonal cutting process and the effect of frequency and amplitude of vibration and laser heating temperature on cutting force are discussed by using FEA method. Research results have revealed that the main peak of the transient force components increase with the increase of vibration frequency, decrease with the increase of vibration amplitude and laser heating temperature. Moreover, the friction reversal phenomenon is improved with the increase of vibration frequency and amplitude, resulting in the decrease of average cutting force. Compared to common cutting and traditional one-dimensional ultrasonic vibration cutting, the composite cutting technology put forward in this paper has unique cutting force characteristics for such super hard material because of combined action of friction reversal and intermittence cutting for ultrasonic elliptical vibration and material softening for laser heating. The research in the paper has provided a practical reference for the further experiments of laser and ultrasonic assisted cutting.
Experimental Study of Tool Wear in Milling Multidirectional CFRP Laminates
Authors: Han Sheng Chao , Chen Yan , Xu Jiu Hua , Zhou Jing Wen
Published: October 2013

This study aims to investigate the wear of coated end mills when milling Carbon fiber reinforced polymer (CFRP) composites. Four different types of end mills are used in the milling experiments to identify the influence of tool geometry and material on tool wear. Cutting forces and wear mechanisms of coated mills are also discussed. Through the contrast experiment, diamond coated multitooth router shows the best performance with the smallest cutting force and the least wear extent under the same cutting parameter. The major failure mechanisms of coated tools are breakthrough of coating, coating flaking and abrasive wear of substrate.
Research on Maintenance Strategy of Large-Scale Grab Ship Unloader Based on Reliability
Authors: Liu Guang Jun , Han Bang Xin , Tan Guang Yu , Li Guang Hui , Sun Yuan Tao
Published: October 2013

t is hard to acquire the failure data of ship unloader and the mean time to failure is not independent identically distributed, and there are many defects existed in the maintenance method such as high cost and bad effect. In this work, we propose a method based on Weibull Distribution model to deal with the failure data of a large-scale grab ship unloader, build up the model of MTBF (Mean Time Between Failure) and preventive maintenance time, and show the example with failure data, which provides references to maintenance of the ship unloader. Finally, we present the decision process of the reliability-centered maintenance strategy, maintenance type of the grab ship unloader and the maintenance of the key parts, which provides scientific decision support for the maintenance of the ship unloader equipments.
Finite Element Simulation of Electromagnetic Properties of Ferrite Material
Authors: Peng Wen Zhen , Wan Shu Min , Lin Bin , Sun Li Peng , Yang Mei Ning
Published: October 2013

As the inductance of magnetic cores is the most important parameter for their service performance. Four coupling models of EE-type ferrite cores are established to analyze the relationship between surface quality and the inductance of ferrite cores. Besides, 3D FEM simulation of different models is made by ANSOFT MAXWELL software. The results show that the surface quality has a direct influence on the service performance of ferrite devices.
The Dynamic Characteristics of Concrete Sawing Based on Wavelet Multi-Scale Analysis
Authors: Hu Shan Shan , Hu Ying Ning , Chen Bang Dao , Wang Yan , Lai Xiao Dong
Published: October 2013

Experiments of diamond sawblade sawing plain concrete are conducted with different sawing parameters. Real time signals of sawing force, vibration, acoustic emission and noise are collected, and Multi-scale wavelet analysis is adopted to analyze the interrelationship and interrelation of real time signals. Supervision and distinction of processing can achieved after Multi-scale wavelet analysis.
Constitutive Relationship and Parameters Optimization of 6181 H18 Aluminum Alloy Hot Forming Process with Synchronous Cooling
Authors: Wang Ning , Chen Guo Liang , Chen Ming He
Published: October 2013

Hot forming process with synchronous cooling is implied to improve the formability of lightweight materials with poor forming performance at room temperature. Its applicability for 6181 H18 aluminum alloy was investigated in this paper, inspired by ultrahigh strength steel hot stamping method. Uniaxial tensile test at elevated temperature with various strain rates were carried out to obtain the constitutive model for simulation and determine the parameters for further orthogonal test. The influence of temperature, holding time and cooling rate on formability and mechanical properties in the hot forming process with synchronous cooling was discussed. An optimized combination of process parameters was obtained which increased its tensile strength and elongation remarkably.
Exceeded Slender Micro-Shaft Machined by Micro-EDM Process
Authors: Zhang Kai Zhen , Zhu Bo , Wang Yu Kui , Wang Zhen Long
Published: October 2013

In this study, a micro-EDM process of exceeded slender micro-shaft is proposed. It could be divided into two parts, rough machining and finish processing. In rough machining procedure, the micro-shaft feeds along the radial and motions periodically along axial direction. High machining voltage is adopted to improve machining efficiency. In finish machining procedure, the micro-shaft feeds along radial and motions along tangential direction. Low open voltage is adopted to improve surface quality and reduce explosive force. By combining rough machining and finish machining, a high surface-quality micro-shaft with a diameter of 25μm and high aspect ratio of 120:1 was fabricated.
Structure Design and Research of Heat Pipe Cooled Hot Forging Die
Authors: Cheng Wei , Liang Ping
Published: October 2013

This paper describes the structure of heat pipe cooled hot forging die. A computational method was used to predict the temperature field of the die structure model. The research results show that the heat pipe can be effective cooled hot forging die, the temperature values of around heat pipe have a declining greater, thus significantly reducing the thermal load of the hot forging die, to further extend the life of the die.
Study on Tool Life and Tool Wear Mechanisms in Dry Cutting Pure Iron
Authors: Kong Jin Xing , Li Liang , Xu Dong Ming , He Ning
Published: October 2013

Pure iron is a kind of high plasticity and toughness material. In the process of cutting pure iron, the tool wear is very serious. In this paper, three kinds of cutting tools KC5010, K313 and 1105 are used in the cutting pure iron process and the tool wear tests in dry cutting condition with different cutting parameters have been carried out. According to the results, the tool wear mechanisms and tool life of three kinds of cutting tools have been compared and analyzed. It is concluded that the tool life of K313 is better than KC5010 and 1105 and the three kinds of tool mechanisms are primarily adhesion wear, diffusion wear and oxidation wear.
Proterozoic Stratigraphy of northeastern British Columbia
Authors: Bell R T
Published: October 2013

Proterozoic rocks of northeastern British Columbia are divisible into three successions. The lower and oldest, of probable Helikian age and consisting dominantly of quartzites and carbonate rocks, is at least 11,000 feet thick and is divided into the Chischa,
Tetsa, George, Henry Creek, and Tuchodi Formations. The middle succession, also of probable Helikian age, consists of atleast 8,000 feet of shaly flysch and is divided into the Aida and Gataga Formations. The uppermost succession of phyllites, slates, and greenstones is at least 5,000 feet thick and
is probably of Hadrynian age but may be as young as Early Cambrian. The Gataga Formation and older units are cut by diabase dykes and underwent gentle deformation in the Late Proterozoic.
Quaternary geology of western Melville Island, Northwest Territories
Authors: Hodgson D A
Published: October 2013

The western peninsula of Melville Island includes the highest elevations in the western Arctic Archipel­ago. At the centre are the Blue Hills plateaus, lying 400-750 m a.s.l., which are dissected on the margins and eut radially by cliffed sea inlets. The longes!
of several transecting scarps forms the border with northern lowlands. Sorne important morphological elements date/rom the Paleozoic; planation swfaces are likely Tertiary peneplains, but the origin of other such elements as the inlets, linear coastlines, and adjacentflatfloored channels, is
equivocal. Most of the peninsula is mantled by up to several metres of frost disaggregated bedrock. This weathered rock, derivedfrom a variety of clastic and calcareous sediments, includes discrete areas of fines, sand, mixed fines and rubble, and rubble. These materials bear no clear
ùulicators of glaciation, other than marginal meltwater channels on coarse mate rials tracing retreat of local ice from some coasts to the interior. Scattered patches of till, ice contact deposits, and undated raised glaciomarine deposits were left by a partial caver of local glacial ice, which
was at least 300 m thick in places. Circumstantial evidence suggests a Late Wisconsinan age for this event; however, the highest evidence of marine overlap does not conform to the uplift pattern expected from an island ice cap. Rare erratics of southern provenance at al! elevations indicate
inwulation by continental ice, probably in early Quaternary time. The M' Cl ure glacier, at the northwest li mit of the Late Wisconsinan Laurentide ce Sheet, pushed onto the south coast earlier than 11.7 ka. Modern and inactive fluvial sediments are the most widespread Quaternary deposits. Emergent
shoreline deposits are rare. Static plateau glaciers are not relictsfrom the Pleistocene, but datefrom post-Hypsithermal cooling, when even more extensive areas were intermittent/y blanketed by perennial snow caver.
Ressources en gaz dévonien dans le bassin sédimentaire de l'ouest canadien
Authors:   Geological Survey of Canada
Published: October 2013

The assessment of Devonian gas potential in the Western Canada Sedimentary Basin involved geological delineation and statistical evaluation of the established mature plays, and statistical evaluation of conceptual plays using the 25 identified established mature
plays as a representative population of all Devonian gas plays. Results of the assessment suggest that the total Devonian gas resource in the Basin is in the order of 3 528 000 x 106m3 (126 TCF). Fifty-six per cent of this gas volume remains to be discovered; 40 per cent is contained in conceptual
plays and 16 per cent in established mature plays. The estimate of potential of the established mature plays is not overly optimistic; nonetheless some 17 gas pools, larger than 3 000 x 106m3, are predicted to be present in the mature plays. This indicates that several of the mature plays still have
a significant upside potential with respect to undiscovered gas volumes, particularly the Slave Point reef complexes and platform carbonates in northeast British Columbia and northwest Alberta, the Leduc/Nisku reef complexes in the Alberta ``Deep Basin'', and the Swan Hills shelf margin play in
west-central Alberta. Economic analysis of the Devonian gas potential estimates indicate that 16 per cent of the volume of recoverable gas is economic at a price of $1.25 per MCF ($44.13 per 103m3), and 43 per cent at a price of $2.50 per MCF ($88.25 per 103m3). Sensitivity analysis indicates that
the economic potential of undiscovered gas is not greatly affected by cost changes, but can be very sensitive to exploration success rates and distance of discoveries to gathering systems. Estimates of the volume of economic gas potential for the entire Devonian (established and conceptual plays)
are 240 000 x 106m3 (8.5 TCF) at a price of $1.25 per MCF ($44.13 per 103m3) and 634 000 x 106m3 (22.4 TCF) at a price of $2.50 per MCF ($88.25 per 103m3). These last numbers suggest that less than 32 per cent of estimated in-place potential (1 960 000 x 106m3/70 TCF) will be economic unless gas
prices rise above $88.25 per 103m3 ($2.50 per MCF).
Application of case discussions to improve anatomy learning in Syria
Authors: Sabbagh Mohammad Ayman
Published: October 2013

Aims: Designing a new approach for learning gross anatomy to improve students′ motivation to study anatomy and to enable them to learn independently through case discussion. Materials and Methods: The study included newly registered students in the first academic year. The total number of students was 165, who were divided by alphabetical order into 15 groups of 11 students. Each group was led by one faculty member and each faculty member lead 3 groups. Each group met twice a week for 2 weeks to discuss one case related to the upper limb anatomy. Students took pre- and posttests and completed an opinion questionnaire about the case discussions. Results: The pretest score shows that 20% of the students received grades of 60% or above and that 80% received grades less than 60%. The posttest showed that 45% of the students received grades of 60% or above and that 55% received grades less than 60%. There was a significant difference between the pre- and posttest for grades <60% (P = 0.0000) and less significant for grades >60% (P = 0.0023). In addition, 17% of students achieved the same results (less than 60%) in both the pre- and posttests. The questionnaire revealed that all students stated that the discussion method was useful in their learning process, helped them to increase their motivation to study anatomy (85%), know the usefulness of studying anatomy (84%), and understand the problems (91%). Conclusions: The implementation of the case discussion in teaching anatomy can increase the students′ understanding and motivate them to learn.
Frequency, risk factors, and antibiogram of Acinetobacter species isolated from various clinical samples in a tertiary care hospital in Odisha, India
Authors: Dash Muktikesh , Padhi Sanghamitra , Pattnaik Swetlana , Mohanty Indrani , Misra Pooja
Published: October 2013

Background: For the past two decades, Acinetobacter spp. have emerged as an important pathogen globally in various infections. Objectives: This study was conducted to determine the frequency, risk factors, and antibiotic resistance pattern of Acinetobacter spp. from various clinical samples. Materials and Methods: This retrospective, hospital record-based, cross-sectional study included a total of 8749 clinical samples collected from patients at a tertiary care hospital in Odisha, India from July 2010 to December 2012. The samples were processed and identified by standard protocol. The Acinetobacter isolates were tested for antibiotic resistance by Kirby-Bauer disk diffusion method [according to the Clinical and Laboratory Standards Institute (CLSI) guidelines]. Results: From 8749 clinical samples, 4589 (52.5%) yielded significant growth and only 137 (3%, 137/4589) Acinetobacter spp. were isolated. Maximum (56.9%) isolates were obtained from pus/swab, followed by blood (13.1%) and urine (12.4%). Elderly age, being inpatients, longer duration of stay in the hospital, associated co-morbidity, and invasive procedure were found to be significant risk factors in the setup investigated (P is less than 0.05). Out of 137 isolates, 75 (54.7%) were resistant to more than three classes of antibiotics (multidrug resistant) and 8 (5.8%) were resistant to all commonly used antibiotics (pan-drug resistant). Majority of the isolates were sensitive to imipenem, meropenem, and piperacillin/tazobactam, and showed resistance rates of 19%, 22%, and 23%, respectively. All eight pan-drug resistant isolates were 100% sensitive to colistin. Conclusion: This hospital-based epidemiological data will help to implement better infection control strategies and improve the knowledge of antibiotic resistance patterns in our region.
Las empresas en Facebook y Twitter. Situación actual y estrategias comunicativas
Authors: Pérez Dasilva Jesús Ángel , Genaut Arratibel Aingeru , Meso Aierdi Koldo , Mendiguren Galdospin Terese , Marauri Castillo Iñigo , Iturregui Mardaras Leire , Rodríguez González María del Mar , Rivero Santamarina Diana
Published: October 2013

Dada su influencia, las empresas se están viendo obligadas a integrar las redes sociales en sus estrategias de comunicación. Objetivos.  Pretendemos ofrecer una visión general sobre el uso de Facebook y Twitter en las principales marcas comerciales en España y analizamos la actividad de las cuentas más sensibles a las críticas para conocer la estrategia comunicativa de sus responsables. Método. Se han seleccionado las cuentas de las tres marcas con mayor inversión publicitaria en 15 sectores, recopilando y procesando 5.433 tweets y 3.000 posts en una tabla analítica. Conclusiones. Queda demostrada la presencia masiva de estas compañías en las redes sociales, al tiempo que se constata la variabilidad extrema del número de seguidores, el tráfico y la naturaleza de la información. Sin embargo, se ha podido demostrar que el uso que se le da a las distintas redes y las estrategias comunicativas requeridas en unas y en otras son distinguibles e identificables.
Reduced efficacy of marine cloud brightening geoengineering due to in-plume aerosol coagulation: parameterization and global implications
Authors: Stuart G. S. , Stevens R. G. , Partanen A.-I. , Jenkins A. K. L. , Korhonen H. , Forster P. M. , Spracklen D. V. , Pierce J. R.
Published: October 2013

Abstract. The intentional enhancement of cloud albedo via controlled sea-spray injection from ships (marine cloud brightening) has been proposed as a possible method to control anthropogenic global warming; however, there remains significant uncertainty in the efficacy of this method due to, amongst other factors, uncertainties in aerosol and cloud microphysics. A major assumption used in recent cloud- and climate-modeling studies is that all sea spray was emitted uniformly into some oceanic grid boxes, and thus these studies did not account for subgrid aerosol coagulation within the sea-spray plumes. We explore the evolution of these sea-salt plumes using a multi-shelled Gaussian plume model with size-resolved aerosol coagulation. We determine how the final number of particles depends on meteorological conditions, including wind speed and boundary-layer stability, as well as the emission rate and size distribution of aerosol emitted. Under previously proposed injection rates and typical marine conditions, we find that the number of aerosol particles is reduced by over 50%, but this reduction varies from under 10% to over 90% depending on the conditions. We provide a computationally efficient parameterization for cloud-resolving and global-scale models to account for subgrid-scale coagulation, and we implement this parameterization in a global-scale aerosol-climate model. While designed to address subgrid-scale coagulation of sea-salt particles, the parameterization is generally applicable for coagulation of subgrid-scale aerosol from point sources. We find that accounting for this subgrid-scale coagulation reduces cloud droplet number concentrations by 46% over emission regions, and reduces the global mean radiative flux perturbation from −1.5 W m−2 to −0.8 W m−2.
Error budget analysis of SCIAMACHY limb ozone profile retrievals using the SCIATRAN model
Authors: Rahpoe N. , von Savigny C. , Weber M. , Rozanov A.V. , Bovensmann H. , Burrows J. P.
Published: October 2013

Abstract. A comprehensive error characterization of SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric CHartographY) limb ozone profiles has been established based upon SCIATRAN transfer model simulations. The study was carried out in order to evaluate the possible impact of parameter uncertainties, e.g. in albedo, stratospheric aerosol optical extinction, temperature, pressure, pointing, and ozone absorption cross section on the limb ozone retrieval. Together with the a posteriori covariance matrix available from the retrieval, total random and systematic errors are defined for SCIAMACHY ozone profiles. Main error sources are the pointing errors, errors in the knowledge of stratospheric aerosol parameters, and cloud interference. Systematic errors are of the order of 7%, while the random error amounts to 10–15% for most of the stratosphere. These numbers can be used for the interpretation of instrument intercomparison and validation of the SCIAMACHY V 2.5 limb ozone profiles in a rigorous manner.
Online determination of levoglucosan in ambient aerosols with particle-into-liquid sampler – high-performance anion-exchange chromatography – mass spectrometry (PILS–HPAEC–MS)
Authors: Saarnio K. , Teinilä K. , Saarikoski S. , Carbone S. , Gilardoni S. , Timonen H. , Aurela M. , Hillamo R.
Published: October 2013

Abstract. Biomass burning, such as domestic heating, agricultural, and wild open-land fires, has a significant influence on the atmosphere at the global and, especially, at the local scale. Levoglucosan has been shown to be a good tracer for biomass burning emissions in atmospheric particulate matter, and several analytical techniques have been presented for the determination of levoglucosan from filter samples. In this paper, a novel combination of a particle-into-liquid sampler (PILS) to a high-performance anion-exchange chromatograph (HPAEC) with the detection by a mass spectrometer (MS) is presented for the online analysis of levoglucosan in ambient particles. The PILS–HPAEC–MS technique enables a fast online analysis of levoglucosan from the particulate samples. The method was tested at an urban background station in Helsinki, Finland, in winter 2011. A comparison with simultaneous levoglucosan measurements from filter samples by the HPAEC–MS was performed and it showed a good agreement between the online and offline methods. Additionally, the online levoglucosan data were compared with the biomass burning tracer fragments measured by a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). As there were no local biomass burning sources close to the measurement station, online levoglucosan measurements revealed that most of the particles from biomass burning were either regionally distributed or long-range transported in the urban background of Helsinki. The average levoglucosan concentrations were relatively low (average 0.083 μg m−3) during the measurement campaign. The highest concentration peak measured for levoglucosan (1.4 μg m−3) seemed to originate from biomass burning in the Baltic countries, likely in Estonia, that was transported to Helsinki.
A satellite data driven biophysical modeling approach for estimating northern peatland and tundra CO2 and CH4 fluxes
Authors: Watts J. D. , Kimball J. S. , Parmentier F.-J. W. , Sachs T. , Rinne J. , Zona D. , Oechel W. , Tagesson T. , Jackowicz-Korczyński M. , Aurela M.
Published: October 2013

Abstract. The northern terrestrial net ecosystem carbon balance (NECB) is contingent on inputs from vegetation gross primary productivity (GPP) to offset ecosystem respiration (Reco) of carbon dioxide (CO2) and methane (CH4) emissions, but an effective framework to monitor the regional Arctic NECB is lacking. We modified a terrestrial carbon flux (TCF) model developed for satellite remote sensing applications to estimate peatland and tundra CO2 and CH4 fluxes over a pan-Arctic network of eddy covariance (EC) flux tower sites. The TCF model estimates GPP, CO2 and CH4 emissions using either in-situ or remote sensing based climate data as input. TCF simulations driven using in-situ data explained >70% of the r2 variability in 8 day cumulative EC measured fluxes. Model simulations using coarser satellite (MODIS) and reanalysis (MERRA) data as inputs also reproduced the variability in the EC measured fluxes relatively well for GPP (r2 = 0.75), Reco (r2 = 0.71), net ecosystem CO2 exchange (NEE, r2 = 0.62) and CH4 emissions (r2 = 0.75). Although the estimated annual CH4 emissions were small (<18 g C m−2 yr−1) relative to Reco (>180 g C m−2 yr−1), they reduced the across-site NECB by 23% and contributed to a global warming potential of approximately 165 ± 128 g CO2eq m−2 yr−1 when considered over a 100 yr time span. This model evaluation indicates a strong potential for using the TCF model approach to document landscape scale variability in CO2 and CH4 fluxes, and to estimate the NECB for northern peatland and tundra ecosystems.
Pliocene to Pleistocene climate and environmental history of Lake El'gygytgyn, Far East Russian Arctic, based on high-resolution inorganic geochemistry data
Authors: Wennrich V. , Minyuk P. S. , Borkhodoev V. Ya. , Francke A. , Ritter B. , Nowaczyk N. , Sauerbrey M. A. , Brigham-Grette J. , Melles M.
Published: October 2013

Abstract. The 3.6 Ma sediment record of Lake El'gygytgyn, Far East Russian Arctic, represents the longest continuous climate archive of the terrestrial Arctic. Its elemental composition monitored by X-ray fluorescence scanning exhibits significant changes since the Mid-Pliocene caused by climate driven variations in the primary production, postsedimentary diagenetic processes, and current activity in the lake as well as weathering processes in its catchment. During the Mid to Late Pliocene, warmer and wetter climatic conditions are reflected by elevated Si / Ti ratios, indicating enhanced diatom production in the lake. Prior to 3.3 Ma, this signal is highly masked by intensified detrital input from the catchment, visible in maxima of clastic-related proxies such as the K concentration. In addition, calcite formation in the early lake history points to enhanced nutrient flux into the lake caused by intensified weathering in its catchment. Its termination at ca. 3.3 Ma is supposed to be linked to the development of permafrost in the region triggered by a first cooling in the Mid-Pliocene. After ca. 3.0 Ma the elemental data suggest a gradual transition to Quaternary-style glacial / interglacial cyclicity. In the early Pleistocene, the cyclicity was first dominated by variations on the 41 ka obliquity band but experienced a change to a 100 ka eccentricity dominance after the Middle Pleistocene Transition at ca. 1.2 to 0.7 Ma. This clearly demonstrates the sensitivity of the Lake El'gygytgyn record to orbital forcing. A successive decrease of the baseline-levels of the redox-sensitive Mn / Fe ratio and magnetic susceptibility between 2.3 to 1.8 Ma reflects an overall change in the bottom water oxygenation due to an intensified occurrence of pervasive glacial episodes in the early Quaternary. The coincidence with major changes in the North Pacific and Bering Sea paleoceanography at ca. 1.8 Ma implies that the change in lake hydrology was caused by regional cooling and/or changes in the ocean-land moisture transport. Further rising TOC and TN values after ca. 1.6 Ma are attributed to a progressive intensification of the glacial intensity. In the course of the Quaternary glacial/interglacial sequence eight so-called "super-interglacials" occur. Their exceptional warm conditions are reflected by extreme Si / Ti peaks accompanied by lows in Ti, K, and Fe, thus indicating an extraordinary high lake productivity.
Analysis of the drainage density of experimental and modelled tidal networks
Authors: Zhou Z. , Stefanon L. , Olabarrieta M. , D'Alpaos A. , Carniello L. , Coco G.
Published: October 2013

Abstract. Based on a controlled laboratory experiment, numerical simulations of micro-tidal and meso-tidal conditions simulate the initiation and long-term evolution of back-barrier tidal networks. The simulated pattern formation is comparable to the morphological growth observed in the laboratory which is characterised by relatively rapid initiation and slower adjustment towards an equilibrium state. The simulated velocity field is in agreement with natural reference systems such as the micro-tidal Venice Lagoon and the meso-tidal Wadden Sea. Special attention is given to the concept of drainage density which is measured on the basis of the exceedance probability distribution of the unchannelled flow lengths. Model results indicate that the exceedance probability distribution is characterised by an approximately exponential trend, similar to the results of laboratory experiments and observations in natural systems. The drainage density increases greatly during the initial phase of tidal network development while it slows down when the system approaches equilibrium. Due to the larger tidal prism, the tidal basin has a larger drainage density for the meso-tidal condition (after the same amount of time) than the micro-tidal case. In both micro-tidal and meso-tidal simulations, it is found that there is an initial rapid increase of the tidal prism which soon reaches a relatively steady value (after approximately 40 yr) while the drainage density adjusts more slowly. In agreement with the laboratory experiments, the initial bottom perturbations play an important role in determining the morphological development and hence the exceedance probability distribution of the unchannelled flow lengths. Overall, our study indicates an agreement between the numerical and experimental tidal networks on the geometric characteristics.
Autonomous thermal camera system for monitoring the active lava lake at Erebus volcano, Antarctica
Authors: Peters N. , Oppenheimer C. , Kyle P.
Published: October 2013

Abstract. In December 2012, the Mount Erebus Volcano Observatory installed a thermal infrared camera system to monitor the volcano's active lava lake. The new system is designed to be autonomous, and capable of capturing images of the lava lake continuously throughout the year. This represents a significant improvement over previous systems which required the frequent attention of observatory researchers and could therefore only be operated during a few weeks of the annual field campaigns. The extreme environmental conditions at the summit of Erebus pose significant challenges for continuous monitoring equipment, and a custom made system was the only viable solution. Here we describe the hardware and software of the new system in detail and report on a publicly-available online repository where data will be archived. Aspects of the technical solutions we had to find in order to overcome the challenges of automating this equipment may be relevant in other environmental science domains where remote instrument operation is involved.
Informal uncertainty analysis (GLUE) of continuous flow simulation in a hybrid sewer system with infiltration inflow – consistency of containment ratios in calibration and validation?
Authors: Breinholt A. , Grum M. , Madsen H. , Örn Thordarson F. , Mikkelsen P. S.
Published: October 2013

Abstract. Monitoring of flows in sewer systems is increasingly applied to calibrate urban drainage models used for long-term simulation. However, most often models are calibrated without considering the uncertainties. The generalized likelihood uncertainty estimation (GLUE) methodology is here applied to assess parameter and flow simulation uncertainty using a simplified lumped sewer model that accounts for three separate flow contributions: wastewater, fast runoff from paved areas, and slow infiltrating water from permeable areas. Recently GLUE methodology has been critisised for generating prediction limits without statistical coherence and consistency and for the subjectivity in the choice of a threshold value to distinguish "behavioural" from "non-behavioural" parameter sets. In this paper we examine how well the GLUE methodology performs when the behavioural parameter sets deduced from a calibration period are applied to generate prediction bounds in validation periods. By retaining an increasing number of parameter sets we aim at obtaining consistency between the GLUE generated 90% prediction limits and the actual containment ratio (CR) in calibration. Due to the large uncertainties related to spatio-temporal rain variability during heavy convective rain events, flow measurement errors, possible model deficiencies as well as epistemic uncertainties, it was not possible to obtain an overall CR of more than 80%. However, the GLUE generated prediction limits still proved rather consistent, since the overall CRs obtained in calibration corresponded well with the overall CRs obtained in validation periods for all proportions of retained parameter sets evaluated. When focusing on wet and dry weather periods separately, some inconsistencies were however found between calibration and validation and we address here some of the reasons why we should not expect the coverage of the prediction limits to be identical in calibration and validation periods in real-world applications. The large uncertainties result in wide posterior parameter limits, that cannot be used for interpretation of, for example, the relative size of paved area vs. the size of infiltrating area. We should therefore try to learn from the significant discrepancies between model and observations from this study, possibly by using some form of non-stationary error correction procedure, but it seems crucial to obtain more representative rain inputs and more accurate flow observations to reduce parameter and model simulation uncertainty.
A new technique using the aero-infiltrometer to characterise the natural soils based on the measurements of infiltration rate and soil moisture content
Authors: Fulazzaky M. A. , Yusop Z. , Ibrahim I. , Kassim A. H. M.
Published: October 2013

Abstract. Infiltration rate (f) and soil moisture content (θ) are the important factors for water resources management. Accurate measurements of these factors are not so readily available in most farmlands since present measuring equipments are not really suitable. This paper proposes the measuring device that uses a simple method to measure the rate of water infiltration into the ground and to determine the percentage of water contained in the soil. The two empirical equations which formulated on the basis of power regression models of plotting f vs. air pressure dropping rate (P) and θ vs. P are proposed to evaluate the dynamic properties of soil-water and soil–air interface from a three-phase system. All the parameters in equations have physical meanings, and experimental data validation shows that the equations are sufficiently accurate. Aero-infiltrometer was used to measure both the variations of f and θ at three natural soil sites to contribute to operational water management issues and soil texture identification. In the future, new research opportunities on basic knowledge of air diffusion into the ground will contribute to more versatile techniques in measurement of water infiltration.
A new method for deriving glacier centerlines applied to glaciers in Alaska and northwest Canada
Authors: Kienholz C. , Rich J. L. , Arendt A. A. , Hock R.
Published: October 2013

Abstract. This study presents a new method to derive centerlines for the main branches and major tributaries of a set of glaciers, requiring glacier outlines and a digital elevation model (DEM) as input. The method relies on a "cost grid – least cost route approach" that comprises three main steps. First, termini and heads are identified for every glacier. Second, centerlines are derived by calculating the least cost route on a previously established cost grid. Third, the centerlines are split into branches and a branch order is allocated. Application to 21 720 glaciers in Alaska and northwest Canada (Yukon, British Columbia) yields 41 860 centerlines. The algorithm performs robustly, requiring no manual adjustments for 87.8% of the glaciers. Manual adjustments are required primarily to correct the locations of glacier heads (5.5% corrected) and termini (3.5% corrected). With corrected heads and termini, only 1.4% of the derived centerlines need edits. A comparison of the lengths from a hydrological approach to the lengths from our longest centerlines reveals considerable variation. Although the average length ratio is close to unity, only ~ 50% of the 21 720 glaciers have the two lengths within 10% of each other. A second comparison shows that our centerline lengths between lowest and highest glacier elevations compare well to our longest centerline lengths. For > 70% of the 4350 glaciers with two or more branches, the two lengths are within 5% of each other. Our final product can be used for calculating glacier length, conducting length change analyses, topological analyses, or flowline modeling.
El concepto de poder en las relaciones internacionales y la necesidad de incorporar nuevos enfoques
Authors: Creus Nicolás
Published: October 2013

El propósito de este artículo es analizar las diferentes concepciones del poder presentes en la disciplina de las Relaciones Internacionales, poniendo de manifiesto la insuficiencia de los abordajes tradicionales y la necesidad de ampliar la perspectiva teórica. De este modo, se espera avanzar hacia una comprensión más profunda y acabada del concepto. Tal como lo advierten muchos autores, es menester romper con la tentación simplificadora de definir el poder exclusivamente en términos de la posesión de recursos. Un avance fundamental radica en reconocer su carácter relacional y explorar las diferentes dimensiones en que opera. La ampliación del horizonte teórico resulta tan necesaria como inevitable.
Motion Control of a Quadrotor Aircraft via Singular Perturbations
Authors: González-Vázquez Salvador , Moreno-Valenzuela Javier
Published: October 2013

In this paper, a new motion controller for a quadrotor aircraft is introduced. A reformulation of the control inputs of the dynamic model is discussed and then the control algorithm is given in a constructive form. The stability proof of the state space origin of the overall closed-loop system relies on the theory of singularly perturbed systems. Numerical simulations corroborate the viability of the proposed control scheme and the conclusions concerning stability. A set of simulations under practical conditions is also presented, where the system is affected by different types of disturbances and nonlinearities such as noise and actuator saturation.
A Passive Dynamic Walking Model Based on Knee-Bend Behaviour: Stability and Adaptability for Walking down Steep Slopes
Authors: An Kang , Chen Qijun
Published: October 2013

This paper presents a passive dynamic walking model based on knee-bend behaviour, which is inspired by the way human beings walk. The length and mass parameters of human beings are used in the walking model. The knee-bend mechanism of the stance leg is designed in the phase between knee-strike and heel-strike. q* which is the angular difference of the stance leg between the two events, knee-strike and knee-bend, is adjusted in order to find a stable walking motion. The results show that the stable periodic walking motion on a slope of r <0.4 can be found by adjusting q*. Furthermore, with a particular q* in the range of 0.12< q*<0.18, the walker can walk down more steps before falling down on an arbitrary slope. The walking motion is more stable and adaptable than the conventional walking motion, especially for steep slopes.
Experimental Investigation of Radio Signal Propagation in Scientific Facilities for Telerobotic Applications
Authors: Parasuraman Ramviyas , Kershaw Keith , Ferre Manuel
Published: October 2013

Understanding the radio signal transmission characteristics in the environment where the telerobotic application is sought is a key part of achieving a reliable wireless communication link between a telerobot and a control station. In this paper, wireless communication requirements and a case study of a typical telerobotic application in an underground facility at CERN are presented. Then, the theoretical and experimental characteristics of radio propagation are investigated with respect to time, distance, location and surrounding objects. Based on analysis of the experimental findings, we show how a commercial wireless system, such as Wi-Fi, can be made suitable for a case study application at CERN.
Strategic Planning and Design of Supply Chains: A Literature Review
Authors: Lambiase Alessandro , Mastrocinque Ernesto , Miranda Salvatore , Lambiase Alfredo
Published: October 2013

In this paper, a literature review of the mathematical models for supply chain design is proposed. The research is based on the study and analysis of publications of the last twelve years from the most widespread international journal about operations management and logistics. The aim of the work lies in identifying tendencies in the literature and related open issues about the strategic decisions, economic parameters, constraints and model features considered in the strategic planning and design of supply chains. After a description of the review methodology, comparison parameters and paper exhaustiveness, some guidelines are given in order to support future works in this field.
Design and Characterization of a Novel High-Power Series Elastic Actuator for a Lower Limb Robotic Orthosis
Authors: Accoto Dino , Carpino Giorgio , Sergi Fabrizio , Tagliamonte Nevio Luigi , Zollo Loredana , Guglielmelli Eugenio
Published: October 2013

A safe interaction is crucial in wearable robotics in general, while in assistive and rehabilitation applications, robots may also be required to minimally perturb physiological movements, ideally acting as perfectly transparent machines. The actuation system plays a central role because the expected performance, in terms of torque, speed and control bandwidth, must not be achieved at the expense of lightness and compactness. Actuators embedding compliant elements, such as series elastic actuators, can be designed to meet the above-mentioned requirements in terms of high energy storing capacity and stability of torque control. A number of series elastic actuators have been proposed over the past 20 years in order to accommodate the needs arising from specific applications. This paper presents a novel series elastic actuator intended for the actuation system of a lower limb wearable robot, recently developed in our lab. The actuator is able to deliver 300 W and has a novel architecture making its centre of mass not co-located with its axis of rotation, for an easier integration into the robotic structure. A custom-made torsion spring with a stiffness of 272.25 N·m·rad–1 is directly connected to the load. The delivered torque is calculated from the measurement of the spring deflection, through two absolute encoders. Testing on torque measurement accuracy and torque/stiffness control are reported.
Separated Calibration of a Camera and a Laser Rangefinder for Robotic Heterogeneous Sensors
Authors: Yu Lingli , Peng Meng , You Zuo , Guo Ziqi , Tan Ping , Zhou Kaijun
Published: October 2013

The fusion of the heterogeneous sensors can greatly improve the environmental perception ability of mobile robots. And that the primary difficulty of heterogeneous sensors fusion is the calibration of depth scan information and plane image information for a laser rangefinder and a camera. Firstly, a coordinate transformation method from a laser rangefinder coordinates system to an optical image plane is given, and then the calibration of the camera's intrinsic parameters is achieved by “Camera Calibration Toolbox‘. Secondly, the intrinsic and extrinsic parameters are separated for calibration are proposed and compared, in which the characteristic parameters' identification is according to some characteristic points on the intersection line. Then Gaussian elimination is utilized for the initial value. Furthermore, the parameters' optimization using the non-linear least square and non-linear Gauss-Newton methods is devised for different constraints. Finally, the simulated and real experimental results demonstrate the reliability and effectiveness of extrinsic and intrinsic parameters' separated calibration, meanwhile, the real-time analysis is achieved for robotic multi-sensor fusion.
The Integration of Nanotechnology and Biology for Cell Engineering: Promises and Challenges
Authors: Krishnan Uma Maheswari , Sethuraman Swaminathan
Published: October 2013

Introduction: Successful tissue engineering strategies leading to the regeneration of a tissue depend on many factors, starting from the choice of appropriate scaffold material, tailoring the surface functionalities and topography, providing the correct amount of chemical and mechanical stimuli at the appropriate time points, and ensuring the uniform and precise localization of cells. Further challenges arise when more than one cell type has to be employed for the effective regeneration of an organ.

Importance: Though the use of nanomaterials has improved tissue engineering, many pitfalls still exist that present a roadblock in the translation of tissue engineering strategies to clinical practice. Apart from employing different materials with distinct surface functionalities and mechanical properties, various strategies have been employed to manipulate the surface topography and chemistry of scaffolds to create a biomimetic microenvironment for effective tissue regeneration.

Conclusion: This review provides information about the factors influencing tissue engineering, namely geometry, chemistry, mechanics and cells, and the emerging concepts that may well represent the future of regenerative medicine. Electrospinning techniques and their variants, self-assembly, cell-printing techniques and cell sheet engineering, have all been elaborated in detail. These novel techniques may serve to overcome the challenges currently faced in tissue engineering.