bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluid-Long Fiber Interaction Based on a Second Gradient Theory
Authors: Perez Marta , Abisset-Chavanne Emmanuelle , Cueto Elías , Keunings Roland , Chinesta Francisco
Published: July 2015

Most suspension descriptions nowadays employed are based on the Jeffery's model andsome phenomenological adaptations of it that do not take into account size effects, that is, the kinematicsand stresses do not introduce a micro-mechanical characteristic length and thus, the rheologicalproperties become independent of the rod length. New models able to enrich first gradient kinematicsas well as to activate rod-bending mechanisms (needed for explaining the mild elasticity experimentallynoticed) are needed. In this paper we propose a second gradient description able to activate rods bending.
Efficient Solid–Shell Finite Elements for Quasi-Static and Dynamic Analyses and their Application to Sheet Metal Forming Simulation
Authors: Wang Peng , Chalal Hocine , Abed-Meraim Farid
Published: July 2015

Thin structures are commonly designed and employed in engineering industries to save material, reduce weight and improve the overall performance of products. The finite element (FE) simulation of such thin structural components has become a powerful and useful tool in this field. For the last few decades, much attention and effort have been paid to establish accurate and efficient FE. In this regard, the solid–shell concept proved to be very attractive due to its multiple advantages. Several treatments are additionally applied to the formulation of solid–shell elements to avoid all locking phenomena and to guarantee the accuracy and efficiency during the simulation of thin structures. The current contribution presents a family of prismatic and hexahedral assumed-strain based solid–shell elements, in which an arbitrary number of integration points are distributed along the thickness direction. Both linear and quadratic formulations of the solid–shell family elements are implemented into ABAQUS static/implicit and dynamic/explicit software to model thin 3D problems with only a single layer through the thickness. Two popular benchmark tests are first conducted, in both static and dynamic analyses, for validation purposes. Then, attention is focused on a complex sheet metal forming process involving large strain, plasticity and contact.
Characterisation of Tensile Properties Perpendicular to Fibre Direction of a Unidirectional Thermoplastic Composite Using a Dynamic Mechanical Analysis System
Authors: Margossian A. , Bel Sylvain , Avila Gray Luciano , Hinterhölzl R.
Published: July 2015

The ability of a draping simulation to accurately predict the outcome of a forming process mainly depends on the accuracy of the input parameters. For pre-impregnated composites, material must be characterised in the same conditions as forming occurs, i.e. in temperature regulated environment. Given the issues encountered while testing specimens enclosed in a thermal chamber and mounted on a tensile testing machine, new test methods have to be developed. A new approach using a Dynamic Mechanical Analysis system is presented for the investigation of tensile properties perpendicular to fibre direction of unidirectional pre-impregnated composites. Analyses are focused on a unidirectional carbon fibre thermoplastic tape reinforced polyamide 6 in its molten state. Quasi-static tests are performed at forming temperature for different loading rates with specimens of different geometries in order to assess the reproducibility of the test method.
Kinematic Drape Algorithm and Experimental Approach for the Design of Tailored Non-Crimp Fabrics
Authors: Krieger Helga , Kaufmann Dorit , Gries Thomas
Published: July 2015

In the preforming process, the textile is draped into the geometry of the structural part and afterwards consolidated with resin via injection. For preforming processes non-crimp fabrics (NCFs) have become increasingly popular for cost effective applications. For the realization of automated draping of two-dimensional textiles into three-dimensional complex geometries during the preforming process there is a high advantage for the use of tailored textiles compared to textiles with uniform material properties. Large flat surfaces require a high bending stiffness and low shear stiffness due to high structural stability of the textile and small radii of curvature require a low bending stiffness due to good drapeability of the textile. The bending and the shear stiffness of NCFs with a given layup can be influenced by the manufacturing parameters of the knitting yarn. With tailored NCFs it is possible to adapt the manufacturing parameters of the knitting yarn locally in the production direction to improve drapeability and handling of the textile in the preforming process. To use the high potential of tailored NCFs, the development of the new textile structure has to go hand in hand with the characterization and with the simulation of the draping process. An experimental approach and a modelling approach using a kinematic drape algorithm have been developed to define the local stitching parameters for tailored NCFs dependent on the geometry of the component part.
Fretting Fatigue on Thin Sheets
Authors: Gaertner Eduardo Luis , Bressan José Divo , Petry Anne Karollyne
Published: July 2015

The fretting is responsible for many failures of components in the industry. It is present in assemblies like rivet and screw fixture, dovetailjoint, shaft and hub with key, and all connections of two bodies with a contact force and a small induced relative displacement. Topic of studies for decades, the researchers perform experimental tests with some simplification in order to accelerate the phenomenon, some times using standard devices or creating dedicated machines for better representing the behavior of the desired components. There are a few studies with thin sheets, in which the fretting fatigue has more impact because a small reduction of the cross section due to the wear of crack results in a significant increase of stress and rate of crack propatation, decresing the number of cycles until failure. In this work, it wasbuild a device to generate the fretting fatigue with two different shape of contact pad. The specimen is a stainless steel sheet thickness 0.152mm, which fractures and surfaces were analyzed using the SEM and white light interferometer to understand the fractures.
Dry Forming of Aluminium Sheet Metal: Influence of Different Types of Forming Tool Microstructures on the Coefficient of Friction
Authors: Scholz Peter , Börner Richard , Kühn Ralf , Müller Roland , Schubert Andreas
Published: July 2015

In the sheet metal forming industry lubricants are applied in forming processes to expand the technological boundaries by reducing friction and wear. The friction between tool and sheet metal is crucial to the deep drawing process. Due to economic and ecological reasons the aim of the manufacturers is to reduce or even avoid the use of lubricants. Consequently, this approach enables both a shortening of the process chains and an essential saving of resources. The advantages of structured forming tools in lubricated processes concerning the reduction of the coefficient of friction by the appearance of lubricating micro pockets are well-known. However, without using any lubricant this effect does not work. In this case the contact area is reduced by structuring the forming tool which affects the tribological system.In this paper the influence of microstructures with different geometries and surface treatments (uncoated / a-C:H:Si-coating) on the coefficient of friction in dry metal forming of the alloy AA5182 is compared to the frictional behaviour of unstructured forming tools using lubricant as reference. Before coating, the forming tools are machined by milling to generate tribologically effective microstructures. With the use of a strip drawing plant the effects of different surface microstructures and materials on the coefficient of friction are investigated.
Microstructure in Unbent and As-Hot Bent Segments of Thick-Walled P92 Steel Pipe
Authors: Král Petr , Sklenička Vaclav , Kuchařová Květa , Kvapilová Marie , Svobodová Marie , Horvath Ladislav
Published: July 2015

The microstructure of P92 steel pipe processed by hot bending was evaluated in order to characterize the influence of hot bending on microstructure changes in extrados and intrados of bend. The straight pipes, with an outer diameter 350 mm and wall thickness of 39 mm (Productos Tubulares, s.a.u. Spain), were normalized at 1050°C/60min/air and tempered at 740°C/140min/air.The thick-walled P92 pipe was hot bended at 920-960 °C using bending rate 7 mm/min. The bends were normalized at 1050°C/60min/air and tempered at 775°C/140min/air after hot bending. The selected specimens, machined from different locations of pipe, were additionally thermal ageing at 650 °C to simulate microstructure degradation typical for long-term service conditions.Microstructure was investigated by scanning electron microscope Tescan Lyra 3 equipped with NordlysNano EBSD detector operating at an accelerating voltage of 20 kV with specimen tilted at 70° and by transmission el. microscope JEM-2100F.Microstructure investigation revealed that different processing history influenced distribution and size of secondary phases and caused changes in interboundary spacing in straight pipe and bends. It was found that microstructure changes induced during hot bending and subsequent post-bending heat treatment caused deterioration in creep properties of bends in comparison with those of straight pipe.
Multiscale Simulation of Polymer Nanocomposites in Processing: Challenges and Outlooks
Authors: Gooneie Ali , Mattausch Hannelore , Witschnigg Andreas , Schuschnigg Stephan , Holzer Clemens
Published: July 2015

This paper attempts to address current possibilities in the multiscale simulation of polymer nanocomposites (PNCs) in processing. To provide a comprehensive perspective, a number of PNCs were produced by the incorporation of nanoclays in different polymer matrices. The microstructure evolutions of the simulated counterparts of such systems were studied with and without shear flows in a dissipative particle dynamics (DPD) framework spanning from several nanometers up to a few microns. Transmission electron microscopy (TEM) was utilized to contrast the simulations against the actual nanocomposites. A satisfactory precision was achieved in the build-up of the simulated structures. A significant characteristic of anisometric particles was studied, namely the orientation of the particles due to the imposed flows. It was shown that the orientation of such particles could be well described. Finally, opportunities were addressed for the simulations to carry on to the higher scales.
Microstructure and Mechanical Properties of Ti-6Al-4V Manufactured by SLM
Authors: Popovich Anatoliy , Sufiiarov Vadim , Borisov Evgenii , Polozov Igor A.
Published: July 2015

The article presents results of a study of phase composition and microstructure of initial material and samples obtained by selective laser melting of titanium-based alloy, as well as samples after heat treatment. The effect of heat treatment on microstructure and mechanical properties of specimens was shown. It was studied mechanical behavior of manufactured specimens before and after heat treatment at room and elevated temperatures as well. The heat treatment allows obtaining sufficient mechanical properties of material at room and elevated temperatures such as increase in ductility of material. The fractography of samples showed that they feature ductile fracture with brittle elements.
Material Loadings during Electrochemical Machining (ECM) - A First Step for Process Signatures
Authors: Klocke Fritz , Harst Simon , Ehle Lisa , Zeis Markus , Klink Andreas
Published: July 2015

Properties of workpieces, like residual stress in the rim zone, cannot be predicted for manufacturing technologies reproducible in advance. This lack of predictability shall be solved by a new approach, called Process Signatures. These Process Signatures will combine the material loadings forced by the manufacturing process with the change of state variables, e. g. the variation of residual stress in the surface layer. As the Process Signatures shall achieve comparability for different processes with same physical working principle, it is necessary to describe the transition from material loadings to the change of material properties in a uniform way. Consequently an energy based approach is chosen that considers these transitions by the dissipation of the several kinds of energy brought into the manufacturing process and especially in the respective working area.A first step for the development of such Process Signatures is the identification of all process specific material loadings. This paper presents several material loadings generated during the electrochemical sinking process. In a further step the contribution of the individual material loadings to the material removal process are estimated. Finally first approaches for the combination of the main material loadings and the change of material properties are presented.
Modeling, Identification and Simulation of the Sintering Stage for Micro-Bi-Material Components
Authors: Ou Hui Bin , Sahli Mohamed , Barrière Thierry , Gelin Jean Claude
Published: July 2015

This paper investigates the numerical simulation of the sintering stage by solid state diffusion during the metal injection molding process for micro-bi-material component based on a thermo-elasto-viscoplastic model. The physical parameters concerning very fine 316L stainless steel and copper powders with high volume loading contents involved in the sintering model have been identified in order to set up finite element simulations. The experimental tests have been carried out in a vertical dilatometer and the identification of the material parameters have been carried out with Matlab® platform software. Then in order to predict the shrinkage and relative density after densification, a solid state diffusion model for the sintering has been implemented in finite element software to perform the simulation of the sintering stage.
Microstructure Evolution and Hardness Distribution in Al Wires Subjected to Simultaneous Tension-Torsion Deformation
Authors: Pourbashiri Mojtaba , Sedighi Mohammad , Poletti Cecilia , Sommitsch Christof
Published: July 2015

Commercially pure Al wires are drawn through equal channel angular dies with simultaneous torsion. The wires are deformed up to an equivalent strain of 1 to 4 at room temperature after several passes. The microstructure evolution of the wires is investigated using optical microscopy at both longitudinal and transverse cross sections. A grain refinement to a mean grain size of 10 to 15 μm is achieved by using this process. Finer grain structure is observed at the edge area of the wires due to the non-uniform strain distribution. The micro-hardness measurement indicates that the hardness distribution is inhomogeneous and increasing from a minimum value at the wire centre to a maximum value at the wire edge. Finite element (FE) results show that by using a channel angel of 160° and an initial wire diameter of 4 mm during one pass, an equivalent plastic strain of about 0.4 at the wire centre and 0.9 at the wire edge can be achieved. The most important advantage of this process is the ability to impose continuous severe plastic deformation to wires. This new hybrid process could be used as an industrial method for continuous grain refinement of wires.
Injection Blow Moulding Single Stage Process – Approach of the Material Behaviour in Process Conditions and Numerical Simulation
Authors: Biglione Jordan , Bereaux Yves , Charmeau J.Y. , Rinaldi Renaud G. , Balcaen Jean , Chhay Sambor
Published: July 2015

Single stage injection blow moulding process, without preform storage and reheat, could be run on a standard injection moulding machine, with the aim of producing short series of specific hollow parts. In this process, the preform is being blow moulded after a short cooling time. Polypropylene (Random copolymer) is a suitable material for this type of process. The preform has to remain sufficiently melted to be blown. This single stage process introduces temperature gradients, molecular orientation, high stretch rates and high cooling rates. These constraints lead to a small processing window, and in practice, the process takes place between the melting temperature and the crystallization temperature. To investigates the mechanical behaviour in conditions as close to the process as possible, we ran a series of experiments: First, Dynamical Mechanical Analysis was performed starting from the solid state at room temperature and ending in the vicinity of the melting temperature. Conversely, oscillatory rheometry was also performed starting this time from the molten state at 200°C and decreasing the temperature down to the vicinity of the crystallization temperature. The influence of the shear rate and of the cooling kinetics on the enhancement of the mechanical properties when starting from the melt is discussed. This enhancement is attributed to the crystallization of the material. The question of the crystallization occurring at such high stretch rates and high cooling rates is open. A viscous Cross model has been proved to be relevant to the problem. Thermal dependence is assumed by an Arrhenius law. The process is simulated through a finite element code (POLYFLOW software) in the Ansys Workbench framework. Thickness measurements using image analysis are performed and comparison with the simulation results is satisfactory.
Experimental and Numerical Analysis of Liquid-Forming
Authors: Zimmer Johannes , Klein Daniel , Stommel Markus
Published: July 2015

The packaging of liquid products is conventionally realized by using two production stages, which are the stretch blow molding and the filling. In the stretch blow molding process, hot polyethylene terephthalate (PET) preforms are inflated by pressurized air into a cavity to form plastic bottles. In a follow-up process, these packages are filled by a separate machine with the desired liquid product. In contrast to that, liquid-forming combines the blowing and filling stages by directly using the liquid product to form a plastic bottle. Through this substitution, two main challenges arise. Firstly, there are significant inertia effects through the liquid mass, leading to additional reaction forces and a spatially inhomogeneous pressure distribution inside the preform. Secondly, the heat transfer between preform and fluid is drastically increased. Because of this cooling effect, a specific combination of forming speed as well as initial preform and liquid temperatures is necessary to avoid thermally induced preform rupture. This is based on the fact that the formability of PET rapidly declines below its glass transition temperature (Tg). Consequently, a process control requires the knowledge of how the process parameters influence the preform cooling. In this paper, a numerical simulation of the liquid-forming process (LF) is introduced including the preform cooling during forming. In addition, the strain-dependent self-heating effect of PET is implemented. Process experiments under different parameter combinations are conducted using simplified bottle geometry. Through a comparison of the results from experiments and from simulation, the influence of process parameters on the temperature drop and thus on thermally induced failure is determined. In this way, process understanding and control are increased.
Influence of the Variothermal Process Control on Thermoforming of Micro-Structures
Authors: Hopmann Christian , Martens Jonathan
Published: July 2015

Functional surface effects on plastic components are a matter of current research activities. To make these surface effects usable on an industrial scale, new processes have to be developed. Forming processes such as injection moulding are currently used to produce functional surfaces, but machine and tool costs are considerably high. Therefore, it is of high importance to analyse to what extent the thermoforming process can be applied to manufacture micro-structures.The so called In-Mould-Graining (IMG) process is a promising variant of the thermoforming enabling the manufacture of micro-structures. The advantage of the IMG process is, that the structure is formed to the final shape of the part. If the structure on the film surface is set before the forming, the conversion may cause a deformation of the structure. However, the forming accuracy of the IMG process is limited by the rapid cooling of the film at the cold mould surface. A significant time interval between the heating and the forming leads to a cooling of the film, especially at its surface and thereby reduces the forming accuracy in the area of the grains.In this paper it is investigated to what extent the moulding accuracy of the IMG can be increased by the use of a variothermal mould heating. To achieve the required forming accuracy, only the surface layer of the micro-structured region of the cavity is heated by induction before the contact between film and cavity occurs. At the same time, the entire mould is cooled with a conventional water cooling system. The analysis of the process and formed parts shows, that especially the mould temperature during the forming process has a significant impact on the forming accuracy. A forming accuracy of a 50 µm high micro-structure of more than 95 % can be achieved. Furthermore, the contact of angle of a water droplet on a micro structured thermoformed surface can be increased up to + 145°.
Diffusion Effects Induced by Dislocations in Crystalline Materials Subjected to Large Strains
Authors: Paşcan Raisa , Cleja-Ţigoiu Sanda
Published: July 2015

Abstract. We reconsider here the FEM-algorithm for solving the initial and boundary value problems performed within the viscoplastic constitutive framework and proposed in our paper [1]. The problems concerning the deformation of a sheet composed of a single fcc-crystal, generated by different slip systems simultaneously activated, are solved numerically for an in-plane stress state. The variational formulation is associated to the incremental equilibrium equations and is coupled with an update procedure for the state variables, which are described by the differential type equations, as well as for the non-local evolution equations of the dislocation densities. The length scale parameter is introduced into the model through the diffusion-like parameter which enters the evolution equations for dislocation densities. For more accuracy of the simulation, the shape functions have been chosen polynomials with higher than one degree. We do not consider that once a slip system was activated it remains active for the rest of simulation. The activation condition is a key point in the numerical algorithm. As a numerical example, we perform a tensile test of a rectangular and non-rectangular metallic sheet, comparring the results of the simulation when two, respectively eight slip systems are considered.
An Innovative Method to Produce Metal Foam Using Cold Gas Dynamic Spray Process Assisted by Fluidized Bed Mixing of Precursors
Authors: Rubino Felice , Ammendola Paola , Astarita Antonello , Raganati Federica , Squillace Antonino , Viscusi Antonio , Chirone Riccardo , Carrino Luigi
Published: July 2015

Metallic foams are known for their interesting physical and mechanical properties such as high stiffness, very low specific weight, high compression strength, unusual acoustic and thermal properties and good energy absorption characteristics. These materials are currently manufactured by means of several different processes. The limit of these conventional technologies is the impossibility to produce foams with complex geometry.This paper deals with the study of an innovative method to produce complex shaped precursors for aluminum foams through cold gas dynamic spray deposition process (CGDS). Aluminum alloy (Al-Si) fine powders were previously mixed with the blowing agent (titanium-hydride, TiH2). The mixing process was carried out by means of sound-assisted fluidized bed apparatus that allows to obtain an homogeneous mixture of the two elements. The mixed particles were then sprayed by means of the CGDS process on a stainless steel sheet that simulates the real component to be reinforced with the foam. Subsequently the obtained precursor was heated up in a furnace The produced metal foam was characterized using optical and electron microscopy in order to study the cell morphology and distribution.The obtained results showed the effectiveness of this method to produce aluminum foams with complex shape.
Measuring Plasticity in Confined Cu Thin Films at Different Geometries
Authors: Mu Yang , Meng Wen Jin
Published: July 2015

We report quantitative measurement of plasticity in confined Cu thin films with a new micro-pillar testing protocol. Polycrystalline Cu and CrN thin films were sequentially sputter deposited onto Si (100) substrates, forming thin film assemblies in which polycrystalline Cu thin films of various thicknesses were confined between non-deforming Si and CrN. Cylindrical micro-pillars of CrN/Cu/Si were fabricated through scripted focused Ga+ ion beam milling, with the interfaces either normal to the axial direction or at a 45° inclination. The CrN/Cu/Si micro-pillars were compression loaded in the axial direction with a flat diamond punch on an instrumented nanoindenter. The axial compression loading caused extensive plasticity within the thin Cu interlayers with the interfaces in both the normal and inclined orientations, but with distinctly different responses. We show that significant plastic flow occurs within the confined Cu thin films in both normal compression and shear loading. The flow stress of the confined Cu films is dependent on the Cu layer thickness and the deformation geometry. The presently described micro-pillar testing protocol offers quantitative evaluation of the plastic response of thin metal films under different deformation geometries. The present results offer new experimental examples of scale-dependent plasticity in thin metal films, and new experimental test cases for non-local plasticity theories.
The Parametric RSM Model with Higher Order Terms for the Meat Tumbler Machine Process
Authors: Pietraszek Jacek , Seńcio Mariusz , Diakun Jarosław , Gądek-Moszczak Aneta , Stojek Małgorzata
Published: July 2015

Typical design of experiments (DoE) approach to the response surface problem applies the polynomials with at most the second order terms. It is correct due to the Taylor’s theorem when the variability of input variables is sufficiently small. Unfortunately, the variability bound of a designed experiment is planned with high uncertainty about the investigated object’s behavior. If the response of the object has a large curvature then model quality indicators (residuals normality, lack of fit, significance of terms) appear to be unacceptable. In such a case, polynomial terms with the order higher than second should be applied. The paper describes the RSM model with the fourth order terms identified for relationship between settings of a meat tumbler machine (input variables) and the Warner-Bratzler shear force (output variable).
The Impact of Detection Methods on the Results of Quantitative Analysis of the Surface Layer WC-CoAl2O3
Authors: Gądek-Moszczak Aneta , Radek Norbert , Pliszka Izabela
Published: July 2015

In the article authors presented digital measurement problem of the object on the 3D images of the microstructures. As a research material were used the micro tomography image of the probe C45 steel with WC-Co-Al2O3surface layer. Due to relatively low contrast between the surface layer and the root material, and lack of sharp edges, some of the methods for automatic threshold indication may give biased results. Following the initial selection of the many methods of automatic binarization two of them and interactive method was selected to carry out comparative studies. The analysis included assessment of the layer thickness, number of detected objects and total volume of all detected objects.
Seasonal changes in the infestation parameters of the sucking louse, Linognathoides laeviusculus (Phthiraptera: Anoplura: Polyplacidae), infesting Richardson’s ground squirrel (Rodentia: Sciuridae) in Manitoba, Canada
Authors: Yunik Matthew E.M. , Waterman Jane M. , Galloway Terry D.
Published: July 2015

Linognathoides laeviusculus (Grube) (Phthiraptera: Anoplura: Polyplacidae) is a louse found on holarctic ground squirrels but little is known about how the life history, physiology, and hibernation of the host influence its population dynamics. Two hundred and fourteen Richardson’s ground squirrels (Urocitellus richardsonii (Sabine); Rodentia: Sciuridae) were trapped over the summer of 2010, and the age, sex, and mass of all euthanised squirrels were recorded. Squirrels were hand-washed to remove lice, which were then identified to species, stage of development, and sex. Linognathoides laeviusculus was the only louse collected. In total, 5057 lice were collected with 63.6% of the squirrels infested at a mean intensity of 37.2 (90% confidence interval=29.98–48.66). Two peaks in prevalence of L. laeviusculus infestations occurred (April and mid-June), and one peak in intensity (June). Juvenile squirrels had higher prevalence and mean intensity when compared to adults. Adult male squirrels had higher mean intensity compared to adult females. Adult lice comprised most of the population infesting emerging adult squirrels in the spring but nymphs predominated for most of the active season of the host. Infestations were highly aggregated with k=0.203 and index of discrepancy D=0.813. The seasonal dynamics of L. laeviusculus appear to be strongly correlated with the annual cycle of the squirrel host.
Monitoring of insects with public participation (MIPP; EU LIFE project 11 NAT/IT/000252): overview on a citizen science initiative and a monitoring programme (Insecta: Coleoptera; Lepidoptera; Orthoptera)
Authors: Mason Franco , Roversi Pio Federico , Audisio Paolo , Bologna Marco Alberto , Carpaneto Giuseppe Maria , Antonini Gloria , Mancini Emiliano , Sabbatini Peverieri Giuseppino , Mosconi Fabio , Solano Emanuela , Maurizi Emanuela , Maura Michela , Chiari Stefano , Sabatelli Simone , Bardiani Marco , Toni Ilaria , Redolfi De Zan Lara , Rossi De Gasperis Sarah , Tini Massimiliano , Cini Alessandro , Zauli Agnese , Nigro Giulio , Bottacci Alessandro , Hardersen Sönke , Campanaro Alessandro
Published: July 2015

The LIFE project “MIPP” - Monitoring of Insects with Public Participation (11 NAT/IT/000252) is focused on selected insect species (five Coleoptera, three Lepidoptera, one Orthoptera), all included in the annexes II and IV of the Habitats Directive (HD) 92/43/EEC. One important aim is a citizen science initiative where every person may become a citizen scientist and collect faunistic data on the above species throughout Italy. Another objective of the project MIPP is the development of standard methods for monitoring the conserva- tion status of the five target beetle species. One innovative method employed is a sniffer-dog (“Osmodog”), trained to find the rare and endangered hermit beetle, Osmoderma eremita, which lives in veteran, hollow trees. The dog detects the strong smell of mature peach produced by adult males and an odor produced by the larvae. Another objective of the project MIPP is the dissemination of topics such as HD, Natura 2000, importance of dead-wood, Life projects, insect monitoring and conservation.
Total Quality Management implementation in Greek businesses: Comparative assessment 2009-2013
Authors: Vranaki Martha , Vranakis Stergios , Sarigiannidis Lazaros
Published: July 2015

The competition in the Greek manufacturing sector has become very intense and the need for businesses to survive, under these very difficult conditions, forces them to find new ways to increase their profits, but also to attract new customers and to retain old.  A necessary condition for long-term business survival is to maintain a high product quality level. The implementation of Total Quality Management (TQM) approach is a key factor to achieve this goal.The main objective of this research is to identify the current situation as far as the implementation of TQM by Greek manufacturing firms, and finally to compare the results between the current research and the previous research of 2009 (Vranaki et al., 2010). The research model that has been developed incorporates nine factors which are found in literature to influence Total Quality Management. A structured questionnaire has been developed and distributed to executives of 61 companies. Descriptive statistics as well as Structure Equation Modeling (SEM) techniques were used to analyze the data.
Which of DEA or AHP can best be employed to measure efficiency of projects?
Authors: Sánchez Marisa Analia
Published: July 2015

This paper compares Analytic Hierarchy Process (AHP) and Data Envelopment Analysis (DEA) approaches for monitoring projects, in order to determine their performance in terms of economic, environmental and social organizational goals. This work is founded on an existing methodology to select and monitor projects based on DEA, and discusses modifications and additions arising from using AHP. The proposal is applied to a real case. The results indicate that AHP constitutes an insightful approach in situations requiring a modelling of managerial preferences regarding the relative importance of organizational goals.
A robust evaluation of sustainability initiatives with analytic network process (ANP)
Authors: Ocampo Lanndon , Ocampo Christine Omela
Published: July 2015

This paper presents a methodology on evaluating sustainable manufacturing initiatives using analytic network process (ANP) as its base.The evaluation method is anchored on the comprehensive sustainable manufacturing framework proposed recently in literature. A numerical example that involves an evaluation of five sustainable manufacturing initiatives is shown in this work. Results show that sustainable manufacturing implies enhancing customer and community well-being by means of addressing environmental issues related to pollution due to toxic substances, greenhouse gas emissions and air emissions. To test the robustness of the results, two approaches are introduced in this work: (1) using Monte Carlo simulation and (2) introducing structural changes on the evaluation model. It suggests that the results are robust to random variations and to marginal changes of the network structure. The contribution of this work lies on presenting a sustainable manufacturing evaluation approach that addresses complexity and robustness in decision-making. 
Modulation of Saharan dust export by the North African dipole
Authors: Rodríguez S. , Cuevas E. , Prospero J. M. , Alastuey A. , Querol X. , López-Solano J. , García M. I. , Alonso-Pérez S.
Published: July 2015

Abstract. We have studied the relationship between the long-term interannual variability in large-scale meteorology in western North Africa – the largest and most active dust source worldwide – and Saharan dust export in summer, when enhanced dust mobilization in the hyper-arid Sahara results in maximum dust impacts throughout the North Atlantic. We address this issue by analyzing 28 years (1987–2014) of summer averaged dust concentrations at the high-altitude Izaña observatory (~ 2400 m a.s.l.) on Tenerife, and satellite and meteorological reanalysis data. The summer meteorological scenario in North Africa (aloft 850 hPa) is characterized by a high over the the subtropical Sahara and a low over the tropics linked to the monsoon. We measured the variability of this high–low dipole-like pattern in terms of the North African dipole intensity (NAFDI): the difference of geopotential height anomalies averaged over the subtropics (30–32° N, Morocco) and the tropics (10–13° N, Bamako region) close to the Atlantic coast (at 5–8° W). We focused on the 700 hPa standard level due to dust export off the coast of North Africa tending to occur between 1 and 5 km a.s.l. Variability in the NAFDI is associated with displacements of the North African anticyclone over the Sahara and this has implications for wind and dust export. The correlations we found between the 1987–2014 summer mean of NAFDI with dust at Izaña, satellite dust observations and meteorological re-analysis data indicate that increases in the NAFDI (i) result in higher wind speeds at the north of the Inter-Tropical Convergence Zone that are associated with enhanced dust export over the subtropical North Atlantic, (ii) influence the long-term variability of the size distribution of exported dust particles (increasing the load of coarse dust) and (iii) are associated with enhanced rains in the tropical and northern shifts of the tropical rain band that may affect the southern Sahel. Interannual variability in NAFDI is also connected to spatial distribution of dust over the North Atlantic; high NAFDI summers are associated with major dust export (linked to winds) in the subtropics and minor dust loads in the tropics (linked to higher rainfall), and vice versa. The evolution of the summer NAFDI values since 1950 to the present day shows connections to climatic variability (through the Sahelian drought, ENSO (El Niño–Southern Oscillation) and winds) that have implications for dust export paths. Efforts to anticipate how dust export may evolve in future decades will require a better understanding of how the large-scale meteorological systems represented by the NAFD will evolve.
Constraints on methane emissions in North America from future geostationary remote sensing measurements
Authors: Bousserez N. , Henze D. K. , Rooney B. , Perkins A. , Wecht K. J. , Turner A. J. , Natraj V. , Worden J. R.
Published: July 2015

Abstract. The success of future geostationary (GEO) satellite observation missions depends on our ability to design instruments that address their key scientific objectives. In this study, an Observation System Simulation Experiment (OSSE) is performed to quantify the constraints on methane (CH4) emissions in North America obtained from Short Wave Infrared (SWIR), Thermal Infrared (TIR) and multi-spectral measurements in geostationary orbit compared to existing SWIR low earth (LEO) measurements. A stochastic algorithm is used to compute the information content of a variational inversion at high spatial resolution (0.5° × 0.7°) using the GEOS-Chem chemical transport model and its adjoint. Both the SWIR LEO and TIR GEO configurations generally provide poor constraints on CH4 emissions (error reduction <30 %), with the exception of a few hotspots (e.g., Los Angeles, Toronto urban areas and Appalachian Mountains) where the error reduction is greater than 50 %. On weekly time scales and for a GEO orbit, the degree of freedom for signal (DOFs) of the inversion from multi-spectral observations (500) is a factor of two higher than that obtained from a SWIR instrument (255) due to the increase in measurement sensitivity to boundary layer concentrations in the multi-spectral case. On a monthly time scale and for a GEO orbit, a SWIR instrument would reduce error in emission estimates by more than 70 % for hotspots of CH4 sources (emissions > 4 × 105 kg day−1 grid−1) at model grid scale, while a TIR instrument would provide a relative error reduction of 25–60 % over those areas. While performing similarly for monthly inversions, a multi-spectral instrument would allow for more than 70 % error reduction for these emissions for 7 or 3 day inversions. Sensitivity of the inversions to error in boundary conditions are found to be negligible. Moreover, estimates of the model resolution matrix over significant emitting regions (CH4 emissions > 2 × 105 kg day−1 grid−1) show that for all instrument configurations in GEO orbit the inversion is able to independently constrain CH4 sources at spatial scales smaller than 200 km. These results highlight the importance of using observations sensitive to boundary layer concentrations (i.e., SWIR) to achieve significant improvements in constraining CH4 sources compared to current LEO capabilities.
Observed high-altitude warming and snow cover retreat over Tibet and the Himalayas enhanced by black carbon aerosols
Authors: Xu Y. , Ramanathan V. , Washington W. M.
Published: July 2015

Abstract. Himalayan mountain glaciers and the snowpack over the Tibetan Plateau provide the headwater of several major rivers in Asia. In-situ observations of snow cover fraction since the 1960s suggest that the snow pack in the region have retreated significantly, accompanied by a surface warming of 2–2.5 °C observed over the peak altitudes (5000 m). Using a high-resolution ocean–atmosphere global climate model and an observationally constrained black carbon (BC) aerosol forcing, we attribute the observed altitude dependence of the warming trends as well as the spatial pattern of reductions in snow depths and snow cover fraction to various anthropogenic factors. At the Tibetan Plateau altitudes, the increase of atmospheric CO2 concentration exerted a warming of 1.7 °C, BC 1.3 °C where as cooling aerosols cause about 0.7 °C cooling, bringing the net simulated warming consistent with the anomalously large observed warming. We therefore conclude that BC together with CO2 has contributed to the snow retreat trends. Especially, BC increase is the major factor in the strong elevation dependence of the observed surface warming. The atmospheric warming by BC as well as its surface darkening of snow are coupled with the positive snow albedo feedbacks to account for the disproportionately large role of BC in high-elevation regions. These findings reveal that BC impact needs to be properly accounted for in future regional climate projections, in particular on high-altitude cryosphere.
Grain sorting in the morphological active layer of a braided river physical model
Authors: Leduc P. , Ashmore P. , Gardner J. T.
Published: July 2015

Abstract. A physical scale model of a gravel-bed braided river was used to measure vertical grain size sorting in the morphological active layer aggregated over the width of the river. This vertical sorting is important for analyzing braided river sedimentology, for numerical modeling of braided river morpho-dynamics and for measuring and predicting bed load transport rate. We define the morphological active layer as the bed material between the maximum and minimum bed elevations at a point over extended time periods sufficient for braiding processes to re-work the river bed. The vertical extent of the active layer was measured using 40 hourly high-resolution DEMs of the model river bed. An image texture algorithm was used to map bed material grain size of each DEM. Analysis of the 40 DEMs and texture maps provides data on the geometry of the morphological active layer and variation in grain size in three-dimensions. Normalizing active layer thickness and dividing into 10 sub-layers we show that all grain sizes occur with almost equal frequency in all sub-layers. Occurrence of patches and strings of coarser (or finer) material relates to preservation of particular morpho-textural features within the active layer. For numerical modeling and bed load prediction a morphological active layer that is fully mixed with respect to grain size is a reliable approximation.
Time series analysis of the long-term hydrologic impacts of afforestation in the Águeda watershed of north-central Portugal
Authors: Hawtree D. , Nunes J. P. , Keizer J. J. , Jacinto R. , Santos J. , Rial-Rivas M. E. , Boulet A.-K. , Tavares-Wahren F. , Feger K.-H.
Published: July 2015

Abstract. The north-central region of Portugal has undergone significant land cover change since the early 1900s, with large-scale replacement of natural vegetation types with plantation forests. This transition consisted of an initial conversion primarily to Pinus pinaster, followed by a secondary transition to Eucalyptus globulus. This land cover change is likely to have altered the hydrologic functioning of this region; however, these potential impacts are not fully understood. To contribute to a better understanding of the potential hydrologic impacts of this land cover change, this study examines the temporal trends in 75 years of data from the Águeda watershed (part of the Vouga Basin) over the period of 1936–2010. A number of hydrometeorological variables were analyzed using a combined Thiel–Sen/Mann–Kendall trend-testing approach, to assess the magnitude and significance of patterns in the observed data. These trend tests indicated that there have been no significant reductions in streamflow over either the entire test period, or during sub-record periods, despite the large-scale afforestation which has occurred. This lack of change in streamflow is attributed to the specific characteristics of the watershed and land cover change. By contrast, a number of significant trends were found for baseflow index, with positive trends in the early data record (primarily during Pinus pinaster afforestation), followed by negative trends later in the data record (primarily during Eucalyptus globulus afforestation). These trends are attributed to land use and vegetation impacts on streamflow generating processes, both due to species differences and to alterations in soil properties (i.e., infiltration capacity, soil water repellency). These results highlight the importance of considering both vegetation types/dynamics and watershed characteristic when assessing hydrologic impacts, in particular with respect to soil properties.
Improved singular spectrum analysis for time series with missing data
Authors: Shen Y. , Peng F. , Li B.
Published: July 2015

Abstract. Singular spectrum analysis (SSA) is a powerful technique for time series analysis. Based on the property that the original time series can be reproduced from its principal components, this contribution develops an improved SSA (ISSA) for processing the incomplete time series and the modified SSA (SSAM) of Schoellhamer (2001) is its special case. The approach is evaluated with the synthetic and real incomplete time series data of suspended-sediment concentration from San Francisco Bay. The result from the synthetic time series with missing data shows that the relative errors of the principal components reconstructed by ISSA are much smaller than those reconstructed by SSAM. Moreover, when the percentage of the missing data over the whole time series reaches 60 %, the improvements of relative errors are up to 19.64, 41.34, 23.27 and 50.30 % for the first four principal components, respectively. Both the mean absolute error and mean root mean squared error of the reconstructed time series by ISSA are also smaller than those by SSAM. The respective improvements are 34.45 and 33.91 % when the missing data accounts for 60 %. The results from real incomplete time series also show that the standard deviation (SD) derived by ISSA is 12.27 mg L−1, smaller than the 13.48 mg L−1 derived by SSAM.
Gully geometry: what are we measuring?
Authors: Casalí J. , Giménez R. , Campo-Bescós M. A.
Published: July 2015

Abstract. Much of the research on (ephemeral) gully erosion comprises the determination of the geometry of these eroded channels, especially their width and depth. This is not a simple task due to uncertainty generated by the wide range of variability in gully cross section shapes found in the field. However, in the literature, this uncertainty is not recognized so that no criteria for their measurement are indicated. The aim of this work is to make researchers aware of the ambiguity that arises when characterizing the geometry of an ephemeral gully and similar eroded channels. In addition, a measurement protocol is proposed with the ultimate goal of pooling criteria in future works. It is suggested that the geometry of a gully could be characterized through its mean equivalent width and mean equivalent depth, which, together with its length, define an "equivalent prismatic gully" (EPG). The latter would facilitate the comparison between different gullies.