545 research outputs found
The SiC/SiO Nanostructured Core-Shell as Anode Material for Lithium Ion Batteries: Synthesis and HRTEM Characterization
The SiC/SiO nanocmposite was synthesized by a sol-gel method with a following heat-treatment
process. The SiC nanoparticles were coated with SiO, as a result, a core-shell nanostructured was formed.
The processed material was characterized using X-ray energy dispersive spectroscopy (XEDS), high
resolution transmission electron microscopy(HRTEM), fourier-transform IR spectroscopy (FTIR). Data
obtained in this research showed that core-shell nanoparticles of SiC/SiO with an average range size of 20-
40 (nm) may be produced through sol-gel processing. The SiC/SiO core-shell nanocomposite can act as
regarded candidate for high performance anode materials for lithium ion battery applications.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3525
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Application of NDT thermographic imaging of aerospace structures
This work aims to address the effectiveness and challenges of Non-Destructive Testing (NDT) inspection and improve the detection of defects without causing damage to the material or operator. It focuses on two types of NDT methods; pulsed thermography and vibrothermography. The paper also explores the possibility of performing automated aerial inspection using an unmanned aerial vehicle (UAV) provided with a thermographic imaging system. The concept of active thermography is discussed for inspecting aircraft CFRP panels along with the proposal for performing aerial inspection using the UAV for real time inspection. Static NDT results and the further UAV research indicate that the UAV inspection approach could significantly reduce the inspection time, cost, and workload, whilst potentially increasing the probability of detection
A primary offshore wind farm site assessment using reanalysis data: a case study for Samothraki island
The correct strategy for monitoring and assessing marine Renewable Energy Sources (RESs) is of great importance for local/national sustainable development. To achieve this goal, it is necessary to measure in the most precise possible manner the local/regional RESs potential. This is especially true for Offshore Wind (OW) energy potential, since the most precise techniques are long and expensive, and are not able to assess the RESs potential of large areas. Today, Remote Sensing (RS) satellites can be considered the most important land and marine observation tools. The RS tools can be used to identify the interested areas for future OW energy converters installations in large and small-scale areas. In this study, the OW energy potential has been analysed by means of a 40 years wind speed data from the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis dataset of the Samothraki island surrounding area in the Mediterranean Sea. The OW speed potential has been analysed by means of monthly data from ECMWF Interim reanalysis (ERA-Interim) datasets using the Network Common Data Form (NetCDF) format. Automatically, analyses have been carried out using the Region Of Interest (ROI) tool and Geographical Information System (GIS) software in order to extract information about the OW speed assessment of the Samothraki island area. The primary results of this study show that the southwest area of Samothraki island has good potential for future OW farms installation (bottom fixed and floating version) in near and offshore areas. This study shows the OW energy potential per location, as well as the trend of OW speed, which has changed over the past 40 years in the Mediterranean Sea
Suspended nanocrystalline diamond ridge waveguides designed for the mid-infrared
A comprehensive study and design of air-clad suspended ridge diamond waveguides for operation across the 2.5–16 µm spectral range is presented, specifically targeting nanocrystalline diamond (NCD) thin films directly grown on silicon substrates. Three film thicknesses of 520, 1000 and 2000 nm are considered, to cover overlapping sub-bands of 2.5–5, 4–9 and 8–16 µm, respectively. Within each sub-band, the waveguide dimensions for single mode quasi-TE operation are found and the waveguide material losses and bending losses are estimated at each design point. In addition, in each case the minimum required undercut depth and etch hole placement for optical isolation of the waveguide mode from the silicon substrate is also quantified. We also estimate the losses associated with scattering from surface roughness, which is an unavoidable byproduct of the NCD thin film growth process. Our results indicate that despite the relatively low film thickness-to-wavelength ratio, mechanically stable waveguides with good optical confinement and low material and bending losses can be realised to cover the full 2.5–16 µm range. In addition, scattering loss estimations predict a drastic drop in roughness-induced scattering losses above 6 µm, even for relatively rough films. In addition to highlighting the utility of suspended NCD as a versatile platform for mid-infrared integrated photonics, the approaches and results presented here can be used to inform the design of suspended air-clad waveguides in other material platforms
An Experimental study of the initial volumetric strain rate effect on the creep behaviour of reconstituted clays
Clayey soils tend to undergo continuous compression with time, even after excess pore pressures have substantially dissipated. The effect of time on deformation and mechanical response of these soft soils has been the subject of numerous studies. Based on these studies, the observed time-dependent behaviour of clays is mainly related to the evolution of soil volume and strength characteristics with time, which are classified as creep and/or relaxation properties of the soil. Apart from many empirical relationships that have been proposed in the literature to capture the rheological behaviour of clays, a number of viscid constitutive relationships have also been developed which have more attractive theoretical attributes. A particular feature of these viscid models is that their creep parameters often have clear physical meaning (e.g. coefficient of secondary compression, Cα). Sometimes with these models, a parameter referred to as initial/reference volumetric strain rate, has also been alluded as a model parameter. However, unlike Cα, the determination of and its variations with stress level is not properly documented in the literature. In an attempt to better understand , this paper presents an experimental investigation of the reference volumetric strain rate in reconstituted clay specimens. A long-term triaxial creep test, at different shear stress levels and different strain rates, was performed on clay specimen whereby the volumetric strain rate was measured. The obtained results indicated the stress-level dependency and non-linear variation of with time
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Mechanical Strain Tailoring via Magnetic Field Assisted 3D Printing of Iron Particles Embedded Polymer Nanocomposites
The development of efficient, energy saving, eco-friendly and automated manufacturing of free-form variable-thickness polymer composite components has created a step-change and enabling technology for the composites industry seeking geometry tailoring during a mouldless and/or additive manufacturing such as that in 3D printing. The current article presents ongoing research on the 3D printing of polymer nanocomposites embedded with ferromagnetic iron particles. This research involves exposing the nanocomposite to a magnetic field remotely during the fabrication process. The magnetic field is applied unidirectionally by using constant-strength magnets placed on a fused deposition method (FDM) based 3D printing platform. The magnets are symmetrically fixed on both sides of the printed nanocomposite. A high-performance polylactic acid (PLA) grade polymer was selected, which is commonly used for rigid structures. The setup utilised Neodymium magnets with a constant strength below 1T. The printing process maintained a consistent temperature of 220°C for the nozzle and 40°C for the bed. Observations have shown that the nanocomposites being printed undergo permanent macro-scale deformations caused by the extrinsic strains induced by the surrounding iron particles in response to the relatively low magnetic field (<1T). To provide a theoretical understanding of these induced strains, a Multiphysics constitutive equation has been developed. This equation aims to describe the micromechanics of the field-induced strains and study the evolution of magnetisation within a relatively thick nanocomposite (5mm thickness). Experimental measurements have quantified the macro-scale geometric variations achieved during printing, and a correlation has been established between these variations and the extrinsic strains derived from the theoretical solution, i.e. induced 1.3 mm. The theoretical solution accurately provides the description of the actual field induced strains during the 3D printing process provided that precise temperature values for the layers are accounted for. The theory also predicts a high sensitivity of field induced deformation to such temperatures and interconnects the Multiphysics parameters in explicit expressions for the phenomenon occurring. The results demonstrate a viable and disruptive magnetic field equipped fabrication approach with ability to extend to geometry control during its process
A Decision Support Tool for the Selection of Promoting Actions to Encourage Collaboration in Projects for the Agriculture Sector
[EN] Development and innovation agencies promote consortiums of agricultural stakeholders to collaborate in the proposal of projects for public calls. To achieve this partnerships, these agencies should select between different promoting actions to be performed with two objectives: maximize the number of project proposals presented and minimize the resources invested. To support agencies with these decisions, a computer tool based on a multi-objective integer linear programming model is proposed. To deal with the two objectives the weighting sum method is implemented. The model is validated in different scenarios by means a realistic case of an agency in Brittany (France). The results show the conflict between the two objectives considered and the dependency of the solutions on the scenarios defined. As a conclusion it can be stated that: 1) decision-makers should be careful in defining the weights of each objective and 2) the impact of the different promoting actions on the level of stakeholders¿ participation should be precisely estimated.The authors acknowledge the support of the project 691249, RUCAPS: "Enhancing and implementing knowledge based ICT solutions within high risk and uncertain conditions for agriculture production systems", funded by the European Union¿s research and innovation programme under the H2020 Marie Sk¿odowska-Curie Actions.Alemany Díaz, MDM.; Alarcón Valero, F.; Pérez Perales, D.; Guyon, C. (2020). A Decision Support Tool for the Selection of Promoting Actions to Encourage Collaboration in Projects for the Agriculture Sector. IFIP Advances in Information and Communication Technology. 598:534-545. https://doi.org/10.1007/978-3-030-62412-5_44S534545598European Comission Funded Programs. https://ec.europa.eu/programmes/horizon2020Zoie, C., Radulescu, M.: Decision analysis for the project selection problem under risk. IFAC Proc. 34(8), 445–450 (2001)Sadi-Nezhad, S.: A state-of-art survey on project selection using MCDM techniques. J. Project Manage. 2, 1–10 (2017)Caballero, H.C., Chopra, S., Schmidt, E.K.: Project portfolio selection using mathematical programming and optimization methods. In: Paper presented at PMI® Global Congress 2012–North America, Vancouver, British Columbia, Canada, Newtown Square, PA, Project Management Institute (2012)Ahmad, B., Haq, I.: Project selection techniques, relevance and applications in Pakistan. Int. J. Technol. Res. 4, 52–60 (2016)Inuiguchi, M., Ramı́k, J.: Possibilistic linear programming: a brief review of fuzzy mathematical programming and a comparison with stochastic programming in portfolio selection problem. Fuzzy Sets Syst. 111(1), 3–28 (2000)Stewart, R., Mohamed, S.: IT/IS projects selection using multi-criteria utility theory. Log. Inf. Manage. 15(4), 254–270 (2002)Alzober, W., Yaakub, A.R.: Integrated model for MCDM: selection contractor in Malaysian construction industry. In: Applied Mechanics and Materials 548, pp. 1587–1595. Trans Tech Publications (2014)Adhikary, P., Roy, P.K., Mazumdar, A.: Optimal renewable energy project selection: a multi-criteria optimization technique approach. Global J. Pure Appl. Math. 11(5), 3319–3329 (2015)Strang, K.D.: Portfolio selection methodology for a nuclear project. Project Manage. J. 42(2), 81–93 (2011)Benjamin, C.O.: A linear goal-programming model for public-sector project selection. J. Oper. Res. Soc. 36(1), 13–23 (1985)Coronado, J.R., Pardo-Mora, E.M., Valero, M.: A multi-objective model for selection of projects to finance new enterprise SMEs in Colombia. J. Ind. Eng. Manage. 4(3), 407–417 (2011)Mat, N.A.C., Cheung, Y.: Partner selection: criteria for successful collaborative network. In: 20th Australian Conference on Information Systems, pp. 631–641 (2009)Camarinha-Matos, L.M., Afsarmanesh, H.: Collaborative Networks. In: Wang, K., Kovacs, G.L., Wozny, M., Fang, M. (eds.) PROLAMAT 2006. IIFIP, vol. 207, pp. 26–40. Springer, Boston, MA (2006). https://doi.org/10.1007/0-387-34403-9_4Paixão, M., Sbragia, R., Kruglianskas, I.: Factors for selecting partners in innovation projects–evidences from alliances in the Brazilian petrochemical leader. Rev. Admin. Innov. São Paulo 11(2), 241–272 (2014)Duisters, D., Duysters, G., de Man, A.P.: The partner selection process: steps, effectiveness, governance. Ann. Hematol. 2, 7–25 (2011)Zhang, X.: Criteria for selecting the private-sector partner in public-private partnerships. J. Constr. Eng. Manage. 131(6), 631–644 (2005
PVP2011-57695 STUDY OF CREEP RELAXATION BEHAVIOUR OF 316H AUSTENITIC STEELS UNDER MECHANICALLY INDUCED RESIDUAL STRESS
ABSTRACT Compact tension 316H austenitic steel specimens, extracted from an as-received ex-service pressure vessel header, have been pre-compresse
The burden of diabetes mellitus during pregnancy in low- and middle-income countries : a systematic review
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